Group for Earth Observation

The Independent Amateur Quarterly Publication for

Number 30

Earth Observation and Weather Satellite Enthusiasts

June 2011
Inside this issue . . .
John Tellick looks at the
EUMETSAT Earth
Observation Portal
More Accurate Time on
your PC by David Taylor
Les Hamilton takes us to
Uluru
Rob Alblas New HRPT
Decoder
Ice in the Gulf ofScandinavia
USB Receiver Installation
with Geoff Morris
Francis Breame
introduces Enviham
BrowseWhy Francis Greaves
Succumbed to a Digital
Satellite Meter
The Magic of MultiSpectral Imaging withJames Brown
Enhancing Weather
Satellite Images with
GeoSatSignal by Esko
Petäjä
Record Loss of Ozone
Over Arctic
Nigel Heasman’s View
from North Cyprus
Enviham DDS using
Windows XP
Storm Dunlop looks at
the IOS app, Sattelite
Tracker
Computer Corner
Plus much more ...

v

Highlighting Vegetation
John Tellick

Following on from my Libya desert
cultivation article, a couple of vegetation
highlighted images, this time of the Middle
East.
The two images show different parameters
used to show up vegetation on a Metopand NOAA image disseminated on thesame day – 16-03-11.
They show vegetation along the eastern
Mediterranean coast, through Syria andnorthern Iraq, crop cultivation along thebanks of the Euphrates river [like Nile
cultivation] and a wide area of cultivation
between the Euphrates and Tigris rivers
between Baghdad and Basra in Iraq.
Snow covers the mountains of eastern
Turkey, NW Iran, Armenia and Georgia.

The GEO Quarterly

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England.
Tel:
01483 416 897
email: francis@geo-web.org.uk
General Information
John Tellick
email: info@geo-web.org.uk
GEO Quarterly EditorPeter Green‘Hollowtree’
Eggesford, Devon EX18 7QX, England.
email: geoeditor@geo-web.org.uk
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email: les.hamilton@tiscali.co.uk
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East Leake, Loughborough LE12 6PP
England, UK.
email: members@geo-web.org.uk
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Fax:
01509 559 015
Technical Consultant (hardware)David Simmons
email: tech@geo-web.org.uk
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e-mail: ray-geo@lescharriols.eu
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email: tech@geo-web.org.uk
International Liaison
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email: international@geo-web.org.uk
Nigel Evansemail: nigel@geo-web.org.uk

June 2011
Editorial: Peter GreenT

ime seems to have flown very quickly since the launch issue of the GEO Quarterly
in 2004, we are now welcoming you to Quarterly number 30. When you look backat the Quarterlies you can see not only how the layout of the magazine has changed
but also the leap forward in the images that we are now able to process.
e as a group don't really rely on the data we receive to make mission criticaldecisions in our everyday lives but with the software that decodes the data our
lives are enriched. We enjoy viewing ground features or the cloud formations andthen sometimes animating them. Francis Breame has made available to our members
his Enviham Viewer, he was inspired to write this program to make viewing the datafrom this satellite easier and made it available for others to enjoy it free of charge,
read about it on page 24. Likewise Rob AlBlas introduces us to his new HRPT
Decoder as previewed at the Symposium on page 13.
he GEO Symposium has just successfully finished and you will see on page 20 acollage of photographs (thanks to Clive Finnis,David Taylor and Arne van Belle)
to give you a flavour of the event and a taster for the report in Quarterly 31.
t's good to see some new names appearing in the Quarterly, this helps to give themagazine a variety of subjects that we are sure you will find interesting andhopefully inspiring. However we still need more authors to submit articles for yourmagazine. As you can see it need only be one page, it does not need to be highly
technical. Take a look at page 38, John Heath has submitted an article ' Now You See
it Now You Don't' which clearly displays the effect of the sun's angle on theappearance of ground features.
ith more of us using mobile devices, Storm Dunlop has sent us a review of anapp he uses on his iPod Touch, I know that David Painter recently used an app
on his phone to help align his dish so that he could receive Envisat, please let meknow if you are using any of these products and apps so that we can build a databasefor other GEO members to access. To make the alignment of his Envisat dish easierFrancis Greaves succumbed to a digital satellite meter, read about it on page 26.
e are looking forward to bringing you, our members the next 30 issues but wecan't do it without your support, through articles,images but also yourmembership and spreading of the word for GEO.

W

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Contents
Publisher
Published by The Group for Earth
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Company number is 4975597.
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Responsibility
Every effort is made to ensure that thetechnical and constructional articles
published in this Quarterly are correct.
However, the ultimate responsibility is withthe reader to ensure the safety of
constructions and for any interfacing withother equipment. GEO cannot accept
liability for shortcomings in any publisheddesign or any constructions carried out bymembers or other third parties.
Copyright GEO © 2011
The contents of this Quarterly remain theintellectual property of the Group for Earth
Observation Ltd. and its contributors.
Copying of text or images, either from theprinted Quarterly or from any electronicallystored source, is forbidden without
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GEO Report
EUMETSAT Earth Observation Portal
More Accurate Time on your PC
Uluru
New HRPT Decoder
Space Themed Brownie Weekend
Kepton Rally
Invitation to Submit Envi-Ham Images
GEO Symposium Photo Collage
Ice in the Gulf of Scandinavia
Feedback
GEO Shop
Helplines and Internet Discussion Groups
Copy Deadline for the next issue of GEO Quarterly
GEO Membership Renewal Form
Cloud Free Kamchatka Peninsula
USB Receiver Internal Installation
Enviham Browse
Why I Succumbed to a Digital Satellite Meter
The Magic of Multi-Spectral Imagining
Quarterly Question 30
Enhancing Weather Satellite Images with GeoSatSignal
Record Loss of Ozone Over Arctic
Now You See it Now You Don't
View From North Cyprus
Computer Corner
Enviham DDS with Windows XP
Sattelite Tracker App

Francis BellJohn Tellick
David Taylor
Les Hamilton
Rob Alblas
Francis Bell
Francis Bell
Francis BellDavid Taylor

Robert Moore
Geoff Morris
Francis Breame
Francis Greaves
James Brown
Francis Bell
Esko PetäjäJohn Tellick
John Heath
Nigel Heasman
Douglas Deans
Mike Stevens
Storm Dunlop

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22
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GEO Quarterly No 30

Group for Earth Observation

June 2011

Francis Bell
SymposiumThis report has been written just a few days after our 2011
symposium meeting at the National Space Centre, Leicester.
From my perspective and the feedback I have received fromthose who attended the day’s events were successful andenjoyed.
The day was split between presentations relating to earth
observation and workshops / demonstrations of direct
reception of satellite images. Very entertainingly in the
background there were the activities in the NSC’s exhibitionareas where for the day they were running a theme based on
the film(s) Star Wars. Some of our GEO members took
photographs which give some flavour to the relaxed nature ofthis event.

In my opening remarks to our meeting I expressed my thanks
to those members who had come from abroad to be at our
meeting: four from Holland, two from France plus GEO
Members from all parts of the UK.
I hope that a fuller report will be in our next Quarterly which
will also include a report of the AGM together with financial
reports. I will be progressing the themes which seemed toemerge from our meeting relating to cooperating with othergroups and organisations who have an overlapping interest
with GEO. We have contacts with TORRO (The TORnado andStorm Research Organisation) and RMetS (Royal
Meteorological Society. Importantly the meeting recognised
the decline in GEO membership numbers and action plans
were agreed to address this issue. In the meantime please
don’t forget to renew your own membership when it
falls due. It was also noted that our website was inneed of restructuring and again plans are in hand forthis important job.
There is an audio recording of all the day’s events andI will make these available in due course.
Having experienced a successful weekend in Leicester
the next major event within a few weeks time is GEO’s
visit to Darmstadt.
GEO’s visit to Darmstadt 7th and 8th July 2011
A notice relating to GEO’s visit to Darmstadt appearedon page 24 of our last Quarterly 29 and also details are
published on our website; these notes will bringmembers up to date with the arrangements for our
visit.
The visits to EUMETSAT HQ in Darmstadt, their
ground station at Usingen
and the tour of theEuropean Space Operations Centre (ESOC) in
Darmstadt have all been confirmed and only finedetails still have to be arranged. If you wish to registerfor this visit please do so as soon as possible because
there may have to be a cap on numbers if the demandis excessive. Use the website to register but if all else
fails email international@geo-web.rog.uk with yourdetails.. It is essential that a definitive list of delegatesis available to our hosts at EUMETSAT and ESOC
because they are both high security establishments. It
is also essential that you bring with you some form ofphoto identity to exchange for a security pass whenentering these establishments.
Our visit to ESOC may be extended beyond a routine
visit because we have a contact who works at ESOC
perhaps giving us access to view facilities not on thenormal tour route. The fine detail of this arrangement
still has to be confirmed.

GEO company secretary Nadine Bell (left) and GEO shop manageress Carol
Finnis at the NSC being escorted by storm troopers to keep them out oftrouble'. Photograph Clive Finnis

2

As indicated on previous notices there is no charge forthese visits except something to cover the shared coachhire to Usingen and the tour guides for ESOC. These
costs will depend on numbers but is likely to be about
15 or 20 Euros payable when we are together in Darmstadt.

www.geo-web.org.uk

June 2011

The programme as it stands is:Thursday 7th July 2011

Group for Earth Observation

15.15 Coffee Break
15.30 MTG

09.00 Assemble outside the EUMETSAT
HQ building.
09.30 Arrival and Registration at
EUMETSAT
09.45 Welcome address by Head ofOperations

16.00 Final Questions and Group
Photo
Friday 8th July 2011
09.00 Assemble outside EUMETSAT
HQ building for the coach to Usingen

09.50 UNS

10.00 to 12.00 noon Tour of Usingenground station

10.10 NPP

13.00 Back in Darmstadt

10.45 Coffee break
11.00 MSG METEOSAT

13.30 Tour of ESOC. Our group will be
split into two parallel groups for thistour.

11.15 METOP / EPS

3.00 pm End of visits and dispersal.

11.45 EUMETSAT Evolution

There are many hotels in Darmstadt
but delegates may wish to stay at the
low cost ETAP Hotel Kasinostrasse 4 6 64293 Darmstadt Telephone ++ 49
6151 393720

GEO Quarterly No 30

Quarterly Question 29
My thanks to those who took aninterest in Quarterly Question 29
and submitted a correct answer.
They were:Elmar Bogels Brunssum, Ruud
Jansen The Netherlands
Mike Bragg Timaru New ZealandKen Barker UK
Frank Skillington UK

12.30 Lunch
13.30 Tour of Data Centre
14.00 Tour of Control Centre

www.geo-web.org.uk
www.rmets.org

14.30 Future / 3rd. Party (?)

The question related to the nameof the river shown on an Envisat
high resolution single channel
image I had received at home on
my Envi-Ham system. The name of
the river is Ogooue and it flows
through the country of Gabon inwest Africa. The mouth of the riveras it discharge into the Atlantic isvery close to the equator. As an
aside I did ask how many words
you knew which contained fivevowels and one consonant. I did
receive several replies but they are
now buried in my archives.

www.torro.org.uk

Douglas Deans, Cecilia Taylor, Les Hamilton
One of the occasional lunch-time meetings of GEO members "North of the border". This one held on 2011 April 12, celebrating 50 years of manned space flight(the date by pure chance) Photo by David Taylor

www.geo-web.org.uk

3

GEO Quarterly No 30

Group for Earth Observation

June 2011

EUMETSAT
Earth Observation Portal
John Tellick
EUMETSAT changed the process for registration and applying
for data services in January 2011 by creating a ‘one stop shop’
the EO Portal.
This can be accessed by clicking the data access tab on
EUMETSAT’s website home page and then clicking the EO
Portal registration link from the list of services displayed.
Every new application for access to EUMETSAT’s data will firsthave to open a personal account.
Having done this you can then apply for data services, makechanges and add additional services later.
Those of us who registered for EUMETCast many years ago
have automatically been given a user account and sent anemail requesting activation of this account.
I was unsure about my account status so Debbie of User
Services kindly forwarded me this information which I hope
you will find useful.
Well – when you registered (all those years ago), you did nothave an ‘account’ with EUMETSAT.
When we created your EKU, this is what we call an EKU
account – We assign you with a username and password andwe wrote your EKU to the account and activated the data on
the account.
When we created the EO Portal, we created an EO Portal
account for all existing EKU holders and sent them information
on how to activate the account.
Quite a few still have not activated their EO Portal
account, they need to do this because this is how theyshould request extra data, extra EKU and license renewals.
If any user cannot find the email or cannot remember theirusername and password for the EO Portal, they should
contact us for help.
In January we integrated the Data Centre into the EO Portal,
there were some users who already had an EKU so the Data
Centre service was added to their subscription. Most users did
not already have an account so we did the same again, we
created accounts for them and sent them information on how
to activate the account – along with tutorials and such.
The next phase is to add the UNS to the EO Portal – so making
the portal a one stop shop for all of our services.
The product Navigator can also be accessed via the tool.
One of the things I like is that if you find the product that you
want in the Product Navigator, then go to distribution and hit
the blue EUMETSAT Data Centre link it takes you to the data
centre with the product preselected – you can either go to thetool as guest or log in and there you are.
The aim of the EO Portal is that the user is in charge of what
they receive, how they receive it, their user details and their
UNS subscriptions. It does not take us out of the loop as we

4have to follow the change requests in our systems.
The biggest advantage of the EO Portal is that it is dynamic,
when you registered, all you could tick was HRIT, IODC andprobably FSD, this form was set in stone so to speak so when
new products came online the users didn’t know they could
have access to them too. Whereas now, when a new productcomes along it isw in the EO Portal the day of release.
Give it a go - Login in to your EO Portal, go to Service
Subscriptions, EUMETCast, View/Edit and then in the data
section hit modify, you will then see tick boxes, the ones
already ticked are activated on your EKU the others are freefor you to request.
If you would like to order some archived data, all you do is hit
the data centre tab in the blue bar and the tool opens with you
already logged in.
The main point really is that all existing users alreadyhave an EO Portal account, if they cannot access it, theyshould contact us for help, rather than create a second
account.
The EO Portal page has useful wtutorials regarding how tocreate a new user account, updating your account/forgotten
passwords etc and applying for various data services here:
http://www.eumetsat.int/Home/Main/DataAccess/EOPortal/
SP_201003189442539?l=enen

The Challenge: At what altitude are the aircraft flying? From Q29

An answer?
Hello David,
I did three separate calculations for A, B and C and thealtitudes came out at 28892, 26625 and 26782 respectively. It
would be interesting to know where the aircraft took off from.
Regards Frank Skillington
Frank,
I've now had chance to look at over 200MB of data for the day
in question, and I find it impossible to resolve which theseaircraft are, and therefore what height they were flying at, atthe time of interest, and what their departure airport was. I amvery frustrated by this! However, I see aircraft today flying on
a not dissimilar route, at flight levels of FL32, FL34 and FL36
(32,000 34,000 and 36,000 feet), so your values are at least
reasonable.
Note that the true altitude will not be exactly 32,000 feet (etc.),
as that's a nominal height referred to an atmospheric pressureof 1013.25 hPa. As the actual atmospheric pressure varies,
so the true height varies, for a constant Flight Level. As it
varies for all aircraft in the same way, the intended verticalseparation is maintained!
Cheers, David Taylor

www.geo-web.org.uk

June 2011

Group for Earth Observation

GEO Quarterly No 30

David Taylor
Whether it be for the accurate tracking of weather satellites,
accurate triangulation, or comparing the timing of events on
your PC versus other PCs in your LAN or across the world,
accurate timekeeping on your computer can be important for
its correct operation.
I have previously described in GEO Quarterly how you can
use the freely available NTP software and multiple Internet
time sources to make your PC accurate to within better than
one second [1]. Now, how you can make it really accurate atvery little extra cost?
High Accuracy at Low Cost
What if you need (or want) greater accuracy—say better than
10 milliseconds, or even down to the millisecond level orbetter? To do this, you will need a local time reference, andtoday the best and most easily obtainable reference is the
GPS constellation—flying atomic clocks which are easilyreadable to the microsecond level from the ground.
In the past, extracting accurate time from GPS might haverequired a large, heavy and expensive box of electronics. But
today, devices such as the Garmin GPS 18x LVC are available
relatively cheaply (US $100, £70) although they still require
you to build a small interface to connect with your PC.

Figure 1 - The Sure GPS Evaluation Board

What about a £25 (US $35) package from China, which
performs very well, and which includes not only the precise
GPS time receiver but also the magnetic puck antenna, USB
and RS-232 interfaces, and even the USB lead? Such is theSure GPS evaluation board [2] , illustrated in figure 1.
Below you can learn how to connect it to your PC, and how
to configure NTP to use this board and turn your PC into avery mean time machine, for use by itself or as the reference
clock for your network.
For more details about setting up, configuring, and testing
NTP on Windows PCs, please see my Web page at
http://www.satsignal.eu/ntp/setup.html

Patching the Board
In order to meet the PPS (pulse per second) over RS-232
requirement, additional connections (patches) must be added
to the board. The purpose of these patches is to provide an
RS-232 level PPS signal on pin 1 (DCD line) of the connector.
Whilst the PPS signal on test point TP9 could be used(figure 2), it is at CMOS level and not RS-232 level, and may
not be recognised correctly by the RS-232 receiver chip inyour PC. You can try it if you like, of course. I have provided
a Serial Port LEDs program [3] to show the status of the
RS-232 control lines. Fortunately, there is an unused CMOSto-RS-232 level converter gate available in U6, with its input
on pin 11 and its output on pin 14. However, as this is aninverting gate, and we want a positive going PPS signal, it
should be driven with a negative going PPS signal. Thatavailable at TP9 is positive going however, and it is also used
to drive the ridiculously bright blue LED through a CMOS
inverter gate in U5; so by taking the output from that
inverter on pin 8 of U5 we have the required negative-going
PPS signal to drive U6.

Figure 2 - The Sure GPS Evaluation Board showing Test Points

The patches on the upper surface of the board are shown (inred) on figure 3. All that's needed on the lower surface is the
addition of a lead from pin 14 of U6, through the board, topin 1 of the RS-232 connector.
Using the Sure Evaluation Board
My initial tests were with a Windows 2000 system running
ntpd 4.2.7p97-o, where the board worked perfectly once the
NTP serial rate had been changed from the NTP default of
4800 baud to the board default of 9600 baud. To ensure thatNTP did not select the wrong second (by interpreting one of
the trailing NMEA sentences as near the second marker), it
was also necessary to set bit 1 (decimal 2) of the 'mode'parameter. The settings I used are shown in figure 4.

www.geo-web.org.uk

5

GEO Quarterly No 30

Group for Earth Observation

June 2011

Figure 3 - The red patch wires, added by the author, to provide an RS-232 level PPS output: top of the board (left) and bottom of the board (right).

# ref-clock drivers
server 127.127.22.1 minpoll 4server 127.127.20.1 minpoll 4 mode 18 prefer# PPS - serialpps.sys - on COM1:# NMEA serial port, 16 = 9600 baud, 2 = $GPGGA

Figure 4 - NTP Settings

Previous testing with the same NTP version had
demonstrated the importance of selecting the $GPGGA
sentence where, on a Dell PC running Windows XP, it
seemed as if the NMEA was sometimes picking up on thewrong second—or at least showing a substantial offset.
In an early test, using a higher baud rate and $GPGGA
selection, the NTP jitter seen on the Windows-7 PC was thesame whether the Garmin GPS 18 puck or the Sure-GPS
board were used. The same was true on the Windows 2000
PC, even with the default 9600 baud rate and default NTP
configuration. No tests have been made to compare the PPS
signal on a more precise level but, on the basis of present
tests, I believe it to be within 10-20 microseconds, and likely
within a microsecond or better. I'd love to hear of any moreexact measurements.
I'm currently testing two of these Sure Electronics boards,
with the magnetic antenna puck indoors (on the top floor ofa two storey building), and both a Windows XP and a
Windows-7 64-bit system. The Windows-7 64-bit systemshows an averaged jitter of about 40 microseconds, and theWindows XP system 2.5 to 3.5 microseconds. Both are using
Dave Hart's kernel-mode serial driver replacement [4], andhave the NTP interpolation enabled (it has to be forced 'on'with the Windows-7 system). I've written up the Windows-7
system [5], which is of particular interest, as normally you
are not allowed to use unsigned drivers on such a system.
The Windows XP system has a similar NTP configuration.
Figures 5 and 6 show data from these two PCs, where theoffset reported by NTP is plotted against the time of day. The
difference between the XP system with its smoother, slowerchanging trace but greater offset, and the Windows-7 systemwith its smaller but more rapidly changing offset, is typical.
This may simply be due to the difference between thesoftware clock rates. I would expect a system using FreeBSD

to perform even better, and I have had a report of success on
this platform, also using 9600 baud.
Testing the Board
Before making any changes to the board, you may want totest its function. You will need to download some softwarefrom this web page
http://www.sure-electronics.net/download/
index.php?name=GP-GS010&type=0

The Items to get are:     http://www.sure-electronics.net/download/down.
php?name=MStar%20MiniCDU.zip   !% &http://www.sure-electronics.net/download/
down.php?name=GPS.zip

Start by setting up the board with USB power (no need for adata connection) and the antenna, then leave it for several
minutes until the blue LED starts flashing. The LED
sequence is blue (short flash), yellow (longer flash) then thegreen LEDs only (for about the same duration as the yellow).
This might take as long as 15 minutes on the first run, when
the whole satellite almanac may need to be downloaded.
Now find a free serial port on your PC (mine was a USB toserial adapter on COM4), and connect the device to that portwith a standard 9-pin, male to female serial cable.
Checking that the Board is Working
Unzip MStar MiniCDU.zip, to a convenient location (such as
C:\Tools\Sure\) then double-click on MiniCDU_V1.0.5a.exe
to run the utility. From the menu bar, select <Mode, Setup
COM port menu> to match your PC's COM port and ensurethat the baud rate is set to 9600, as that is what the unit
uses out-of-the-box (figure 7).

Figure 5 - Intel Pentium 4: 1.9 GHz, 1 GB, Windows XP SP3
offset μs (-) offset μs (+)

6

www.geo-web.org.uk

Figure 6 - Intel i5-760: 8 GB, Windows-7 64-bit
offset μs (-) offset μs (+)

June 2011

Group for Earth Observation

GEO Quarterly No 30

Extract the contents of the zip file GPS.zip, perhaps into thesame directory you used before. You will find several files
present, including GPS.exe and help.html, as well as three
sub-directories. Double-click on help.html if you want to read
how to change the baud rate.

The terminal window should now start to fill with groups of
NMEA sentences in one-second batches, starting with$GPGGA and finishing with $GPRMC. You should get
location details and satellite signal levels recorded as well
(figure 9).

Double-click GPS.exe to run the utility and obtain the
dialogue screen illustrated in figure 10. Here you can set theinitial port and baud rate.
On my PC the port is
COM4, and the initial baudrate is the default of 9600,
so I have two settings toalter. Once the settings arechanged, press the 'Open'button, and you should see
the program searching
through the various baudrates and COM ports. My
PC settled on 9600 bps
after just a couple ofseconds.

Setting the Board Baud Rate (not needed for NTP)
While not required for NTP use, where the default 9600 baud
works correctly provided you tell NTP to use the first
sentence ($GPGGA), here is how you could set the baud rate
for some other application.

Should you have problems
whereby this software fails
Figure 10 - The GPS.exe Dialog Screen
to recognise your GPS, it
may be that you need to
update your Java to a more recent version. Now you shouldbe able to set the baud rate to a new value. As an example,
set the baud rate to 115,200 and press the 'Set' button

Figure 7 - Matching the PC COM Port

Click on 'OK' to save the COM
port settings. You should now
be able to click on the connect
icon, the first in the toolbar at
the top (figure 8).
Figure 8 - The Connect Icon

Figure 9 - The active terminal Window

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GEO Quarterly No 30

and, in the confirmation dialogue that
follows, click 'OK'. You should now see
a 'success' message confirming thechange (figure 11). You can check thatthe baud rate has indeed changed by
re-running the MiniCDU_V1.0.5a.exe
program and setting the 115,200 baudrate there before pressing the 'Connect'
button.

Group for Earth Observation

June 2011

Configuration for the Reference PC
This PC requires to be connected to the Sure GPS unit. Ideally, a real serial port ispreferred, and COM1 is assumed in the configuration file (figure 13).
If all you have is a serial port over USB (i.e. a USB to serial cable adaptor) that's
better than nothing—provided the port emulation includes the DCD line (pin-1 ofthe 9-pin RS-232 connector).
As the serial-over-USB built into the Sure board may not include emulation of the
DCD line with the pulse-per-second signal, it is unlikely to be anything like asaccurate, and I do not recommend that you to use it.
You will want to play with using the kernel-mode serialpps.sys driver for better
performance on this reference PC, as well as trying NTPD_USE_INTERP_DANGEROUS=1 on Windows Vista or Windows-7 systems, but you will not needto alter the configuration file to test these options [6].
# Use drift filedriftfile "C:\Tools\NTP\etc\ntp.drift"# ref-clock drivers - Sure Electronics GPS board
server 127.127.22.1 minpoll 4 # PPS - serialpps.sys
server 127.127.20.1 minpoll 4 mode 18 prefer # NMEA serial port, 16 = 9600 baud, 2 = $GPGGA

Figure 11 - Successful Baud Rate Change

Configuring your Network for NTP
For readers less familiar with NTP, here
is a very brief guide to setting up thevarious Windows PCs. I assume thatyou have already installed NTP for
Windows and have a working
configuration.
In what follows, I assume that at least
the stratum-1 PC has a fixed IP addressof 192.168.0.3. If need be, you willneed to alter this to suit your own
network. Alternatively, you can use thePCs name if it's a Windows PC or you
know how to edit your HOSTS file. It isalso assumed that NTP is installed in
the C:\Tools\NTP\ folder: which you
may also have to change to suit yourown installation. The basic minimum
configuration is shown.
If you don't have a COM port on theback of your PC, don't worry as
many modern PCs do have COM port
support built into the motherboard,
although the 9- or 10-pin header is
not wired to a 9-pin male connector
on the back panel.You may be able tocannibalise an old PC for a suitableback-plate and header, or get one
from Amazon—search on '9-pin serial
header'. Choose the right size foryour PC's backplane: for example,
StarTech.com 9-Pin Serial to 10-Pin
Motherboard Header Slot Plate(figure 12).

# Use pool NTP servers as a backup
server 0.uk.pool.ntp.org minpoll 10server 1.uk.pool.ntp.org minpoll 10server 0.nl.pool.ntp.org minpoll 10server 1.nl.pool.ntp.org minpoll 10
Figure 13 - Configuration File for the Reference PC

Configuration for the Connected PCs
The aim here is to make the LAN- or wireless-connected PC talk to the stratum-1
server more frequently than normal, so that it has a better timekeeping
performance. This is achieved with the 'maxpoll 5' option, which forces polls to be
at 32-second intervals maximum (32 = 25). To make sure that the Internet backup
servers are contacted no more frequently than is absolutely necessary, they are
set to a 1024 second interval (1024 = 210).
The configuration file appear in figure 14.
# Use drift filedriftfile "C:\Tools\NTP\etc\ntp.drift"# Use local stratum-1 NTP server - you will need to alter this address
server 192.168.0.3 iburst maxpoll 5 prefer# Use pool NTP servers as a backup
server 0.uk.pool.ntp.org minpoll 10server 1.uk.pool.ntp.org minpoll 10server 0.nl.pool.ntp.org minpoll 10server 1.nl.pool.ntp.org minpoll 10
Figure 14 - Configuration File for the Connected PCs

Have fun with the Sure GPS evaluation board, and do report back to us on how
you get on. You can email me at
david-taylor@blueyonder.co.uk

References
1 Setting the correct time on your computer - GEOQ 1, page 25
2 Sure Electronics
http://www.sureelectronics.net/goods.php?id=99
3 Serial Port LEDs Program
http://www.satsignal.eu/software/net.htm#SerialPortLEDs
4 Dave Hart Serial Driver
http://www.davehart.net/ntp/refclock/serialpps-20091228.zip
5 NTP on 64-bit Windows-7 with GPS/PPS
http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html
6 Windows Serial Port GPS/PPS reference clock for NTP
http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html

Figure 128

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June 2011

Group for Earth Observation

GEO Quarterly No 30

Les Hamilton

Figure 1 - A 1-meter IKONOS satellite image from January 17, 2004 depicts Australia's famed Uluru, a massive sandstone rock formation located in the outback.
Satellite image courtesy of GeoEye (www.geoeye.com)

If there is one single feature that epitomises Australia morethan any other, it must surely be the Uluru rock formationof the island continent's Red Centre. Located in the Simpson
Desert, 450 kilometres southwest of Alice Springs, Uluru is
portrayed here, at 1-metre resolution, by the sensors aboard
GeoEye's IKONOS satellite.
Uluru is composed of red arkose sandstone and rises to849 metres above sea level, though only 348 metres above
the surrounding terrain. Possibly the largest single rock on
the planet, Uluru measures 3.6 by 2 km and 9.4 km in
circumference and extends several kilometres beneath the
Earth's surface (though its exact extent has not been
established).
Uluru is a major tourist attraction and travellers come fromall around the globe to visit it. Apart from its imposing bulk
as it rises steeply from the plains, the most captivating
aspect of Uluru is its beautiful range of colours, whichchange throughout the day. Sunrise and sunset are
particularly remarkable, when the rock glows deep rusty red.

Photographs of Uluru almost invariably show the rock to bered, although the arkose sandstone of which it is composedis actually grey in colour. The sandstone is, however, rich iniron-containing minerals, and it is oxidation of these,
resulting in the formation of iron oxides (basically rust)which is responsible for the red colour. The glowing effect atsunrise and sunset and the shimmering changes of hue
shown by Uluru arise from reflective minerals such as quartz
and mica within the sandstone which reflect and refract the
sun's rays. The reddish soils surrounding Uluru and theirlocation in the heart of the Outback have given rise to theregion’s nickname: Australia’s 'Red Centre'.
Climbing Uluru
The local Anagu Aboriginals do not climb Uluru because they
consider it sacred and they have positioned a sign at thebase of the rock requesting that visitors do not climb iteither. But many of the tourists who arrive at Uluru do sowith the specific intention of making an ascent to its
summit. Since the rock stands in one of Australia's nationalparks, there is nothing in law to prevent visitors climbing it.

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Indeed, it was made a condition that the Uluru climb should
remain open for tourists when the Anagu owners received
the title to the lands in 1985. So, although climbing is notencouraged locally, the tourist industry actually promotes
the climb. The first tourists are likely to learn of the 'no
climb' request comes if they read the details on their entry
ticket to the Uluru-Kata Tjuta National Park. And
understandably, after travelling perhaps thousands ofkilometres to reach Uluru, they are unlikely to forgo theascent, given that it is not actually illegal to do so.
The climb is not without risk, even though there is a marked
route to the summit, with, on the steeper sections, chain
hand holds. These are illustrated in figures 5 and 6 opposite,
kindly sent to us by GEO reader Ken Morgan. In hot desert
weather, the climb normally takes over an hour to complete,and prospective climbers must be fit, carry plenty drinking
water and be sensibly attired against the sun's rays. Overthe years, there have been over 30 fatalities on Uluru, mostly
due to heart attacks, and emergency radio alarms are
installed at numerous locations around the rock.

Figure 3 - A typical sunset view of Uluru
Photo: Ken Morgan

Creation of Uluru
Uluru stands within the Uluru-Kata Tjuta National Park, inAustralia's Northern Territory. Kata Tjuta, meaning 'many
heads', refers to another impressive rock formation 25 km
west of Uluru, commonly known as The Olgas. Anothersandstone rock formation comprising 36 magnificently
domed and coloured shapes, Kata Tjuta covers about
35 km2. But just how were these amazing rocks formed?
900 million years ago, the region that is now Uluru-Kata
Tjuta National Park was a shallow sea known as theAmadeus Basin. For over 300 million years, rivers
transported huge quantities of sand and gravel from major
mountain ranges nearby into this basin. Among the deposits
were two particularly large alluvial fans, several kilometres
deep: one, composed primarily of sand eventually became
Uluru, the other a conglomerate of sand, gravel, pebbles andboulders became Kata Tjuta. Over the aeons, both fansbecame buried under further sediments and were subjected
to pressure, folding and uplift, so much so that the strata in
Uluru are now almost vertical. The rock masses of Uluru andKata Tjuta are much more resistant than those surrounding
them and erosion over millions of years has left themstanding proud above the neighbouring plains.

Figure 4 - Hordes of visitors setting off on the trek to the summit of Uluru
Photo: Ken Morgan

Uluru Today
Uluru is located in a semi-arid desert region which you
would anticipate to imply that it experiences a hot, dry
climate. And so it does—most of the time! Uluru is generally
photographed basking under a cloudless blue sky (figure 3),
which is probably why many who have never been there
mistakenly believe that it never receives any rain at all. But
the long-term mean annual rainfall at Uluru is 27.8 cm. It is
this rain, as it flows from the rock, that encourages thegrowth of the dark algae that highlight the rock channels in
its sides and maintains the verdant pools around its base(figure 9), with lush, green foliage and a multitude of wildlife.
Nevertheless, the majority of its visitors never see Uluru in
the rain. Also, temperatures can fluctuate wildly: from 5°C in
July to 37°C in January. So hot is it during the summer thatclimbs on Uluru must be completed by mid-morning.

10

Figure 5 - The waymarked path up Uluru
Photo: Ken Morgan

Figure 2 - Kata Tjuta, photographed by Christian Mehlführer

Figure 6 - Handrails assist as the summit of Uluru is neared

Image licensed under Wikipedia Creative Commons

Photo: Ken Morgan

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June 2011

Group for Earth Observation

GEO Quarterly No 30

Figure 7 - Uluru from the ISS on March 8, 2011

Figure 8 - Kata Tjuta from the ISS on April 30, 2010

Image: NASA/Douglas Wheelock

NASA Astronaut photograph ISS023-E-29806

Despite its harsh climate, Uluru-Kata
Tjuta National Park is home tonumerous species of animals: 21 native
mammals, 178 birds and 73 reptiles
plus thousands of invertebrates,
including ants, spiders and bugs. The
park is also home to at least sevenspecies of bat which spend the hot
daytime hours roosting in the manycaves and crevices of Uluru and Kata
Tjuta.
Uluru contains countless interesting
cracks, canyons, caves and naturalformations, all of which the Anangu
attribute to the activities of theirancestors at the Creation. Some of theshallow caves at the base of the rockcontain carvings and paintings, someancient and others contemporary.
Often, old cave drawings are painted
over with new ones, so that the rockart, which includes figures likeboomerangs, human beings, waterholes and abstract symbols, is
impossible to date with any certainty.
Views from the ISS
Uluru and Katya Tjuta have both been
imaged from the International Space
Station. Figures 7 and 8 highlight the
deep clefts in both massifs as they are
imaged from above with the sun low inthe sky.
Mythology of Uluru
Archaeological finds indicate that there
has been human settlement aroundUluru for over ten thousand years. The
Anagu believe that, in the Dreamtime,
their ancestors created the entire
landscape as well as all living things
found there. Uluru itself is considered
as a particular manifestation of thisactivity and is therefore held to behighly sacred by the Aboriginal tribesin the area: to this day they continueuse it for rituals and leave paintings in
its caves.

Magic at Uluru
The low annual rainfall around Uluru,
coupled with generally hightemperatures, means that such
precipitation as occurs rapidly dries up.
Just occasionally, however, Uluru
receives torrential rainfall, such as theovernight storm that hit it on
October 14, 2010. Given that only
15 centimetres of rain fell on the rockduring the whole of 2009, nearly half ayear's total—almost 7.5 cm—fell duringthat single overnight storm.
Landscape photographer Peter Carroll
was in the right place at the right time
when the rain came bucketing down,
and took a series of photographs inwhich Uluru is barely recognisable.
Peter was at Yulara, the township near
Uluru, when he was wakened at 3 amby the sound of torrential rain. Peter
had visited Uluru many times
previously but never in conditions suchas these, and it had been a 20-year
dream of his to eventually see the rockwith water pouring down its flanks.
Before the sun had even risen, while it
was still dark, Peter drove the
15 kilometres to Uluru, with the rain
still descending in torrents. When hearrived at the Mutitjulu water holecarpark, the road was a flowing torrent
30 cm deep, and he stood in shin deep
water for ten minutes in awe of themagic he was witnessing. Cataracts ofwhite water, roaring and tumbling
down the sides of the rock, werestarting to reveal themselves as thedawn broke. It was pretty spectacular.
The result of Peter's work is an amazingcollection of images (figures 10-15) thatshow Uluru in a whole new light.
Barely recognisable, with silver lines
snaking down the surface and eerie fog
hovering above, the images will no
doubt find a large audience. Several
have already appeared on the front
page of The Australian.

www.geo-web.org.uk

Figure 9
One of the many pools to be foundaround the base of Uluru
Photo: Ken Morgan

If you think rain over Uluru is unusual,
what about snow? Even deep in theoutback, temperatures can, very rarely,
fall low enough for snow to decorate thesummit of Uluru. The last time thisoccurred was in July 1997.
Acknowledgement
Thanks to Peter Carroll for granting
permission to reproduce his
photographs of Uluru in the rain. You
can view more of Peter's photographic
work on his website.
Peter Carroll Photography
PO Box 7915
Alice Springs, NT 0871
Australia
www.petercarroll.photoshelter.com
Further Reading
1 Fauna of Uluru
http://www.ayersrockresort.com.au/fauna/
2 Uluru-Kata Tjuta National Park
http://www.environment.gov.au/parks/uluru/
3 Peter Carroll's Blog
http://petercarroll.visualsociety.com/?p=936

4 Climate of Uluru
http://www.ayersrockresort.com.au/climate/11

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June 2011

Figure 10 - Waterfalls cascade down the face of Uluru following torrential overnight rain on October 14, 2010
Image: Peter Carroll

Figure 11
Magic at Uluru as a river of rainfall cascades into Mutijulu Waterhole

Figure 12
Streams cascade down the slopes of Uluru

Image: Peter Carroll

Image: Peter Carroll

Figure 14 - A view of Uluru in the rain, from one of its many caves.
Image: Peter Carroll

Figure 13 - Heavy cloud rests on Uluru as streams of water pour down
the flanks of the red rock into a pool at its base.
Image: Peter Carroll

12

Figure 15 - Another magical picture of cloud-shrouded Uluru in therain.

www.geo-web.org.uk

Image: Peter Carroll

June 2011

Group for Earth Observation

GEO Quarterly No 30

New HRPT Decoder
Rob Alblas
About 15 years ago, back in 1995, I
designed a decoder for HRPT (HighResolution Picture Transmission), thedigital datastream as transmitted by
the NOAA's. The decoder was built
using FPGAs (Field Programmable Gate
Arrays) instead of conventional TTL-likecomponents. The functionality of a
FPGA is determined by a bit-file, loadedat power-up. This makes the designvery flexible: the functionality can easilybe altered by just changing the bit-file.
Decoders for CHRPT (transmitted by
the Chinese Fenyung) and HRI (orPDUS, for the old Meteosat first
generation satellites) were built with thesame hardware, as well as generatorsfor each type. The six bitfiles are stored
into different segments of an EPROM.
By selecting the correct segment before
power-up the bitfile for the desired
decoder or generator is loaded into the
FPGA.
Note that an FPGA is not something
like a processor. It doesn't executecommands; it is more like a big box oflogic gates and flip-flops, connected toeach other in a programmable way. It
is comparable with PLAs
(Programmable Logical Array's), but it
can handle much more complex
designs.
Shortly after finishing these decoders/
generators I lost access to the softwareenvironment needed to convert a digital
design into a bitfile. So changes weren't
possible.
Some years ago Werkgroep Kunstmanen
decided to design a new APT/HRPT
receiver. A new decoder, using state of
the art components, was also something
we wanted.
In the meantime Russia launched a
new polar satellite, which transmits
HRPT-like data: the Meteor-M. A lot ofparameters are the same as for NOAA:
same transmission band (around
1700MHz), same bit-speed, same
bandwidth. So no changes are needed
for receiver, rotors and dish.
The digital information differs just a bitcompared to NOAA's HRPT: 6 channels
instead of 5, but resolution a bit lower(1540 pixels per line instead of 2048).
As such it looks like Seastar: thissatellite did transmit 8 channels with
1280 pixels per line. The importantparameters in these formats, to make it
decodeable, were the same for HRPT
and Seastar: amount of bits per line

and synchronisation pattern were voltages, but the module contains voltage
identical. The rest can be handled by regulators for all of them. Therefore just
one single 5V power-supply for the module
software.
is sufficient.
When the SeaStar satellite firstlaunched (1997) data was not encrypted Fig1 shows this module. It contains:
and the old decoder was indeed capable
The FPGA (in the middle)of handling the data.
Level shifters (the ICs on both sides of
the FPGA)
Alas, the digital format from Meteor
Flash memory for the bit-file, in here
differs with respect to framelength andthe functionality of the FPGA is stored
synchronisation pattern, making the
A XTAL oscillator (49.152 MHz)old HRPT-decoder unusable. Anothervoltage stablizers for all needed
reason for a new decoder! More digital
power supplies.
formats are coming or are alreadyAt the top side of the module 2
present (LRPT, LRIT). These differ a lot
connectors: one for the program cable
compared to HRPT. In the future whenand one for other functional use.
the last NOAA (and with it APT) dies, wewill have to switch to formats like thisanyway, should we wish to continue
direct reception of weather satellites.
Searching for new hardware
The requirements we had in mind for a
FPGA, to realize a new decoder were:

Unlimited access to free designenvironment, to generate the loads
for the FPGA

Easy to handle components

Easy to get, not too expensive
Available for a long time

These requirements appeared not soeasy to meet. Modern FPGAs do havelots of pins, and are SMD. So we looked
for assembled modules. The problem
with most modules is that they are
expensive because they contain LCD
displays for example. Also, they areavailable just for a short time. After ayear or so they are replaced by otherboards. These boards are meant for
prototyping and experimenting, notreally for finished products.
Fortunately we found a suitable small
FPGA-board, containing only the
hardware we really needed. The name ofthis module, GODIL, points to anotheradvantage: it stands for Good Old DIL.
The module is fully assembled, and canbe plugged into a motherboard using
connectors with DIL-spaced pins, so it
is easy to handle.
And there are more advantages. Modern
FPGAs need multiple power-voltages
and 3.3V levels on their pins. The
GODIL-module contains level-shifters,
making it possible to connect it with a
5V environment. The FPGA on themodule (a Xilinx device) needs three

www.geo-web.org.uk

Fig 1 GODIL module

The bottom side of the module contains
two 50-pin connectors (each has 2 rowsof 25 pins; see fig. 2). From these 100
pins 50 are connected to the FPGA, tointerface with the outside world. The
remaining pins are connected to VDD
and GND. (just 1 VDD and 1 GND-pin
need to be connected).
The voltage stabilizers are extremely
small switched types; they don't need
any cooling. (They are hard to find on the
PCB)

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June 2011

All in all the amount of components to connect to each otheris so small that it can easily be build on a experimental circuitboard (fig. 4). In this experimental setup the wire top-rightconnects generator output with decoder input.
Nevertheless a 'real' PCB is designed by one of the members of
our working group.
For up-to-date schematics, bit-files and other details see myweb page [1].

Fig. 2 The bottom side of the GODIL module contains two 50-pin connectors(each has 2 rows of 25 pins)

The display shown at the bottom of Fig 1 is sometimes
delivered for free, together with the GODIL. It can be plugged
directly in the connector shown in Fig. 1 at the bottom of themodule. The design loaded into the FPGA determines what
this display shows.
The new decoder.
The GODIL-module needs just a few extra components tobuild a decoder: (see Fig. 3)
A VCO, used to generate a synchronized clock signal (rightin fig. 3)
A USB-module to connect the decoder with a PC (left)
5V supply
Optional: A 3-digit LED-display, showing e.g. decoder type,synchronisation state etc.
(There are also a few monitor pins which may be connected toLEDs. In Fig. 3 a dual-LED is used to show the in-sync state.
So the LED-display is not a 'must'.)For the USB interface it's possible to use a chip (FT245, SMD)
with a few extra components, but there are also modules
containing all needed components including a USB-connector.
The VCO contains a few components (IC, varicap, trimmer
etc).

Fig. 4 Experimental setup

The FPGA
The GODIL-module is available in a few configurations and
FPGA sizes. Price doesn't differ very much between smallest
and biggest FPGA, so I bought the largest one,the XC3S500.
Although not needed at all for the current decoders (theXC3S250, with half capacity, can easily hold the same design)
it gives some space for possible future decoders and/or
extensions.
The old decoder did need two FPGAs and a RAM module tobuffer the data-stream to the PC. It could hold just 1 of thedecoders or generators. The new FPGA can easily contain all
decoders, generators and the buffer-RAM, and still there isplenty of space available for future decoders. An LRIT/LRPTdecoder, including Viterbi and reed solomon decoding, should
be feasible.
Because generator and decoder are active at the same time thedecoder can easily be tested by simply connecting thegenerator output to the decoder input. The generator uses the
XTAL oscillator present on the GODIL-module.
Software.
The decoded HRPT-data needs to be captured by a PC. The old
decoder did use the parallel port (there is a separate USB
extension, though). The new decoder uses USB only.
I did create software for the old decoder, to write the incoming
data-stream to a file. This software, wsat (NOT wxsat!), is now
adapted, so it can be used with the new decoder, supporting
several new features. With wsat you can also view the resultand do some simple processing (including mapping channels
on different colours). The generated file format is also
supported by David Taylor's HRPTReader, including the new
Meteor.
There are executables for both Linux and Windows see fig 5.

Fig 3 Decoder schematic.

14

The decoder-type (HRPT, CHRPT, MHRPT) can be set by thissoftware. But it is also possible to set the decoder-type via
input pins connected to switches or external logic like a

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June 2011

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GEO Quarterly No 30

The decoder, connected to the microprocessor,
is set to the right type. wsat polls the syncstate of the decoder, and waits. As soon as
the expected satellite is received the decoder
gets in-sync.
wsat reacts by reading the decoder-typewhich was set via-via by WXtrack.
wsat makes a new file and starts recording.
If satellite signal is lost wsat stops recording,and closes the file. This can now be examinedby e.g. HrptReader.
wsat waits for next satellite pass (relying on
Wxtrack doing the right preparations, as
described).
Results
Unfortunately I still don't have a HRPT
receiving station here so I have to do it with
reports of others. At least three people havethe decoder in use, and are very satisfied
with HRPT and MHRPT quality. For HRPT it's
better than the old decoder, CHRPT the
quality is comparable with the old decoder,but that is something I want to improve. The
new decoder has the possibility to use a VCO
at 21.2 MHz instead of 10.6 MHz, which may
increase the quality of CHRPT.

Fig 5 wsat program running Meteor-M reception

microcontroller. In that case the software can read which
decoder-type is active. So instead of software setting the
hardware the opposite is the case, hardware setting thesoftware. This is all done via the same USB-interface.
Programming the flash
The flash-memory on the GODIL-module needs to be
written once, and can be updated later if needed. At powerup the FPGA reads the content of the flash and thefunctionality is set.
To program the flash extra software needs to be installed
and a special cable is needed to connect the PC with theprogram connector on the module. There are cables forparallel-port or USB. Unfortunately the USB-cable is very
expensive (more expensive than all the components of thedecoder together!) therefore currently I use a parallelport
cable.
The programming software is freely available from Internet.
The program is called Impact, which is part of Lab Tools see[3]
The Impact software has a GUI which I don't find easy touse. I know that nowadays it is uncommon to typecommands especially into a Windows environment, but for
loading a bit-file into the flash it is really much easier to doit this way than using the Impact GUI! I have added a .bat
file on my website to make this as easy as possible.

The results from the new METEOR-HRPT satellite arestunning, see fig. 6. This satellite has channels in the visual/near-ifrared area comparable with those of MSG, and it is easy
to produce a nice coloured picture without the need for any
fancy processing. Although it is said that this satellite is apartial failure (probably because of failing calibrations) andtherefore from a professional point of view not 100% usable,for
us it's a very nice addition to the HRPT (like) weather satellites.
Summary: What's neededThis article doesn't contain all the details and schematics. You
can find these on my website, including the bit-files. Here you
can also find links to websites where to obtain the GODIL andUSB modules.
Hardware needed
GODIL50 XC3S500E including female connectors (note that
there are different variants of this module!)
USB-module, e.g. UM245R of FTD, USBMOD4 of Elexol, orArduino's breakout-board (module should contain a
FT245 USB-chip)
10.646 or 21.292 MHz VCO: 74HC04 + some small
components.
Optional OHO_DY1 3-digit display, sometimes delivered forfree with the GODIL module
Or some LED's to show in-sync state etc.
5V power-supply (500 mA)
PCB (or exp. board)

An automated HRPT-system
The new decoder makes it possible to realize a fully
automated HRPT receiving station. This includes setting
the right decoder type for the “satellite to receive next”. Oneof the methods, tried out by one of the 'early users', works
as follows: WXtrack determines when which satellite willpass. Via the serial port (RS232) it outputs info about
satellite position to a microprocessor which in turn drives
the rotor system. Wxtrack can also output pre-pass info
like receiver frequency and catalogue number (i.e., satelliteid). From this the decoder type (HRPT, CHRPT, MHRPT) is
determined.

Software needed:
wsat (Linux or Windows [2])Programming the flash, if you want or need to do this
yourself: (only 1 needed at a time, and if an update of the
bit-file is required)
GOPLCP GOP JTAG adaptor (to connect PC with GODIL
during programming)
bit-file, available from my web-site
ISE development software. Free available from internet;
only the Impact software is needed.

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Links[1] Decoder hardware: http://www.alblas.demon.nl/wsat/
hardware/hardware2.html[3] GODIL-module: http://shop.trenz-electronic.de/catalog/
product_info.php?products_id=635[2] Software: Windows: http://www.alblas.demon.nl/wsat/
software/soft_win.html(This site also contains the programming cable.)[2] Software Linux: http://www.alblas.demon.nl/wsat/software/
soft_linux.html[4] Xilinx ISE environment: http://www.xilinx.com/support/
download/index.htm

Fig. 6: MHRPT image received by Friedrich Duttke using the decoder and software mentioned above

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This image from Keith Fraser, Buffalo, NY showing the pack ice starting to move down the Davis Strait. This
Aqua/MODIS image 2011/098, was acquired on 8th 2011, 15:10 utc @250 meters/pixel. This MODIS image wasprocessed with Les Hamilton’s Smooth MODIS and David Taylor’s CorrectGeometry. Of course 99 years ago on
April 12, the Titanic sailed. Unfortunately one of these bergs got in the way. This is one of the clearest images
this year because of absence of the usual cloud and fog.

GEO Quarterly No 30

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June 2011

A ‘Space’ theme weekend with Brownies
Francis BellI have reported before that my local AmateurRadio Club
(TCARC) have a friendly
relationship with the Alton Brownies. Twicea year the brownies have special events witha sleepover in their HQ building. This spring
the theme for their weekend was ‘Space’. A
member of the local astronomy society cameand gave a well illustrated talk to thebrownies, my radio club provided world wide
amateur radio contacts with other Brownie
groups and to enrich the ‘Space’ theme I
took some GEO materials and also ran live
EUMETCast.
I have to say the Brownies took a genuineinterest in the space equipment andincoming images; plus given to opportunity
would quite sensibly and skillfully operate
the software to feature something in which
they had a particular interest.
Other GEO members may consider
supporting their local youth or adult groups
in a similar way. It is very rewarding to see
how easily young people grasp the technology
and concepts which only a few years ago wasat the frontiers of my own perception.

Four Brownies using the GEO stand at the Alton meeting March 2011. The
brownies from left to right - Phoebe, Kitty, Ffion and Rebecca.v

GEO at the Kempton Rally 2011
Francis BellThe South London Radio and Computer Rally is held twice
an year at Kempton and GEO usually have a stand at thisrally. Setting up the stand does tax your resourcefulness
because we like to run live EUMETCast signals together
with laptops running archived images. Deployment of thedish with its associatedcable run is usually the
first priority and isdependent on which
stand we have been
allocated and access to
the
sky.
The
photographs of the twodishesindicate thecontrast between two
dish location we haveused recently. It isdifficult to assess thenumber of visitors wehave to our standduring the day, perhaps
several hundred. Wetake some membershiprenewals and newmemberships on the
stand
but
as
importantly is theinterest that visitors do
expressinhome
reception of weather
satellite images that we have on display. EUMETSAT arevery supportive and send us posters and literature which isthen freely available from our stand. I always say the best18

place for such materials in on the wall of a school, bedroom,
radio shack or study: much better than such stunningposters sitting in boxes. Also our own GEO literature isavailable to visitors expressing particular interest.

My thanks to David Simmons who manned to stand withme for the whole day. I expect that GEO will attend theautumn Kempton rally on 6th November 2011.

www.geo-web.org.uk

June 2011

Group for Earth Observation

GEO Quarterly No 30

Invitation to Submit Envi-Ham Images
Francis BellAs a licence holder I have been receiving earth images fromthe Envisat satellite for about 18 months. I continue to be
impressed with the spectral range and resolution of theseimages. I have written before in GEO Quarterlies about how toapply for a Envi-Ham licence and listed the hardware andsoftware necessary for direct image reception. I have also
given illustrated talks to amateur radio groups and others
relating to direct home reception of earth images, my purpose
being to encourage others to participate in this dimension ofsatellite image reception. The reward has been that a numberof GEO members and others have applied for and been
granted their own Envi-Ham receiving licence.
The Invitation
To continue the promotion of direct reception of Envisat
images I thought it would be great to publish different
examples of images on a regular basis. This is an invitation foranyone receiving Envisat images to submit to our editor theirmost interesting image each quarter - or when you may havesomething special worth sharing with others. Any part of theworld, any spectral combination, with or without colour andany resolution will be acceptable. The only qualification will bethat it was received directly via Envi-Ham and not an image
extracted from the Internet. At the editor judgement one ormore of these could be published each quarter. Submissions
directly to the editor please.
I repeat the rationale behind this idea is to stimulate others
who I hope will be impressed with the variety and quality of
the images available via the Envi-Ham project. It may also be
worth noting that ESA may in due course release othersatellite data via the Envi-Ham project, so existing licenceholders will have a head start for accessing any new data
streams.
Below is an image I received showing Los Angeles. It is a single
channel black and white image but its high resolution is suchthat the urban sprawl of the city can be seen. Remember thisis single channel black and white image but a three channel
colour composite image is even more impressive. Carelessly I
have lost the exact date this images was received but it lookeda sunny day with snow on the mountains. Beach in themorning skiing in the afternoon.
Although Francis says above any resolution, it is important toremember that what looks good on a PC monitor (72 dpi) does
not always looks as good on the printed page (minimum of
300dpi), so please send me your images in full resolution Ed.

www.geo-web.org.uk

19

GEO Quarterly No 30

20Group for Earth Observation

www.geo-web.org.uk

June 2011

June 2011

Group for Earth Observation

GEO Quarterly No 30

Ice in the gulfs of Scandinavia - MODIS image
David Taylor
This combination of two MODIS segments from 11:05 and11:10 UTC on 2011 March 16, shows ice in three gulfs inScandinavia. In the centre of the image, between Sweden and
Finland there is considerable ice still in both the northern andsouthern parts of the Gulf of Bothnia. Coming further southand east, the Gulf of Finland shows both full and partial icing,with tracks likely formed by icebreaker activity from St.
Petersburg and other ports on the Finish, Russian, andEstonian coasts. Further south again there is icing in the Gulfof Riga, off the Estonian and Latvian coasts.
In Sweden, the North Dellen Lake and Siljan Ring meteorite
craters discussed in the GEO Quarterly no.29 by Ander Höök
are clearly visible.
The Aqua/MODIS data was acquired via EUMETCast, andprocessed with my MODIS L1 Viewer software:
http://www.satsignal.eu/software/modis-L1-viewer.html

www.geo-web.org.uk

21

GEO Quarterly No 30

Dear Pete,
Thanks again for compiling a really
excellent issue, GEO Quarterly 29,
which I thoroughly enjoyed.
However, I could hardly believe my eyes
when I read Storm Dunlop’s letter,suggesting, on the one hand, thateveryone provides satellite image dates
where the month is expressed in letters,
then, on the other, asking that we use‘the internationally recognised scientificmethod of specifying the date and time’.
These two notions are in factincompatible. I’ll explain.
The international expression of date andtime is described by International
Standard ISO 8601, and is a purely
numeric
format—hence
theincompatibility problem: this standard
does not permit the expression of any
part of the date in letters. All dates are
expressed in the familiar year/month/day (yyyy-mm-dd) format, which isreadily extended to include hours,
minutes and seconds (yyyy-mm-dd
hh:mm:ss). The advantages of thisformat are that it is language independent(even China uses it), is readily amenable
to sorting procedures and has a constantlength. It is completely wrong to expressthe ‘month’ part of this date in letters, as
Storm Dunlop’s hybrid system would
have us do. I personally value the ISOdate format, and have used it extensively
for many years in cataloguing andstoring both photographs and electronic
documents. This is also the format inwhich digital cameras embed the date
and time within the format field of each
image.
In narrative text, ‘readability’ is the key
and it is much to be preferred that dates
are expressed in the same way as one
would refer to them in casualconversation: ‘January 21, 2011’, forexample. In other words, ‘in plain
English’. This is the grammaticallycorrect format for including a date in
text or letter headings, having many
years ago superseded the form ‘January
31st, 1961’ taught to me in myschooldays, almost too long ago toremember now. In a magazine such as
GEO Quarterly, it is highly desirable
that all dates follow the same format.
This gives a unified feel to the whole.
As editor, I always tried to adopt the‘plain English’ approach to dates andtimes, using easily understandable
wording such as: ‘This NOAA-19 image
was acquired at 14.23 UT on May 25,
2008. There is absolutely no ambiguity

22

Group for Earth Observation

about this, and it is the simplest task forsuper enthusiasts like Storm Dunlop toconvert this to ‘2008-05-25’ for his own
purposes if he so wishes. Why does
Storm Dunlop expect to see dates in
GEO Quarterly expressed in thisgrotesque format, one to which hardly
anyone relates? It is simply anotherexample of over zealous Political
Correctness. I am a scientist myself, andwhile I do use and value this format fordata archiving and retrieval purposes, I
would never remotely consider using it
in descriptive text. And it certainly has
no place in the pages of GEO Quarterly.
So on with the debate. What do otherreaders think of this matter?
Les Hamilton, Aberdeen, Scotland.

Hi again,
Yes you guys are spoiled (??) withEUMETCast, out here we are lucky to
get 64kbs internet! In the islands
anyway.
There is a move to get a EUMETCast
type service over the Pacific ( a joint
NOAA / Australian Bureau of Met
project) and tentative startup is August
this year.
Present plans are for a Ku Bend service
so will be able to use small antennas
and cheap equipment.
That will assist many small island
countries to get better and more regulardata.
The installation of LRIT receivers hashelped a lot but the region is split in two
with GOES W being received in theeastern Pacific and MTSAT in the West.
Only a few countries can see both andthis presents problems with imagery
and data. GOES has lots of data otherthan imagery where MTSAT has only
imagery,so a Pacific wide data feed will
be magic.
Bit from Miami conference:  
states have noted the low availabilityof environmental and EO information tousers in the region     and communications infrastructure         GEONETCast broadcast footprint overwww.geo-web.org.uk

June 2011

the Pacific region to address this issue.
           requirements and securing funding forthe expansion of the system into thisregion.
"#&# *  <> @   
project (RAPIDCast)
So maybe we won't be so isolated in the
future!
Thanks for the interest ...
Regards
Colin Schulz Australia

Hi,
The actual "act" of receiving thesatellites was what got me into thishobby in the first place, now the vastquantities of data are actually more
complicated to process than receive. A
possible "future" maybe to follow in thefootsteps of others perhaps?
Many organisations have successfullylaunched satellites on the back of otherprogrammes, AMSAT and the highly
successful Surrey Satellite Technology
spin off from a small university
programme are some examples. Is it
possible with our resources to provide a
package to fly with another satellite?
What would be involved?, the costs,
deadlines etc are unknowns; possible
investigations may reveal it is now more
likely that the technology is there now
to provide at least a small imaging
presence on a small satellite
somewhere?
The highly successful FUNcube dongle
receiver seems to be a winner for radio
users (only 80Khz bandwidth), butshows what is achievable as a receiver
project; over 500 sold worldwide toreceive amateur satellites, put into orbit
by amateurs!
http://www.funcubedongle.com/

Why we receive these things?, we all
have our own reasons; we may not beable to put together a radiometer but
many balloon mounted cameras havemade it into orbit; and many more planto!
http://www.huffingtonpost.com/2010/10/16/
father-and-son-send-iphon_n_765369.html

Continued page 44

June 2011

Group for Earth Observation

www.geo-web.org.uk

GEO Quarterly No 30

i

GEO Quarterly No 30

EUMETCast
On-Line Registration
Guide
If you require to register as a first-time user for
any of the free EUMETCast data streams such as
MSG, NOAA AVHRR, Metop etc., or need torenew an existing subscription, this must be done
on-line.
GEO has produced a step-by-step guide to theentire process at
http://www.geo-web.org.uk/eumreg.html
This guide also contains a direct link to the official
EUMETCast on-line registration form, which canotherwise prove somewhat tricky to locate.

GEO Helplines
Douglas Deans
Dunblane, Perthshire, SCOTLAND
All aspects of weather satellites from APT, HRPT
to Meteosat-8 DVB/EUMETCast systems.
   |}~     > | %  !>John Tellick
Surbiton, Surrey, ENGLAND
Meteosat-8 advice - registering for the various
MSG services, hardware and software installationand troubleshooting. John will also field generalqueries about any aspect of receiving weather
satellite transmissions.
   |}~ ~~  > | &%&
Geoff Morris GW3ATZ
Shotton, Flintshire, NE WALES
Geoff has lots of experience with aerial,
co-ax,connectors, mounting hardware etc. and has
also done a lot of work with the orbiting satellites.
Geoff has been a EUMETCast Meteosat-8 user forsome time and is familiar with David Taylor’s MSG
software; he should be able to share his
experiences with newcomers to this branch of thehobby.
  *|}~    > |&% !>Mike Stevens
Portland, Dorset, England.
Advice offered on EUMETCast (MSG and Metop)and APT.
> |;  %  !>
Guy Martin G8NFU
Biggin Hill NW Kent, ENGLAND
Guy is prepared to advise anyone who wishing toreceive MSG/Metop using Windows 2000 or XP.
Can also help with networking and ADSL router
setup..
  &> !%!
Hector Cintron
San Juan, Puerto Rico, USA
Hector is prepared to field enquiries on HRPT,
APT, EMWIN and NOAAPORT   |  > |  ! 
Email contact can of course be made at any time,
but we would ask you to respect privacy by
restritricting telephone contact to the period 7.009.00 pm in the evenings.

iiGroup for Earth Observation

Internet News/
Discussion Groups

June 2011

The Copy Deadline for

GEO Quarterly No 31
is Saturday, 30th July, 2011

There are a numerous Internet-based discussion
groups available to weather satellite enthusiasts.
You can join any of these by sending an e-mail tothe appropriate address, with a request to
subscribe. Indeed, a blank e-mail containing theword ‘subscribe’ in its Subject line is all that isrequired. Some of the more useful groups andtheir contact addresses are listed below.
APT Decoder
This is a group where users of Patrik Tast’s
APTDecoder can share information and problems.
http://tech.groups.yahoo.com/
group/APTDecoder/
GEO-Subscribers
This is GEO’s own group, where members can
exchange information and post queries relating to
any aspect related to weather satellite reception(hardware, software, antennas etc), Earthobservation satellites and any GEO-related matter.
http://tech.groups.yahoo.com/
group/GEO-Subscribers/
Satsignal
An end-user self help group for users of David
Taylor's Satellite Software Tools (SatSignal,
WXtrack, GeoSatSignal, HRPT Reader,GroundMap, MSG Data Manager,
AVHRR Manager and the ATOVS Reader).
http://tech.groups.yahoo.com/group/SatSignal/
MSG-1
A forum dedicated to Meteosat Second Generation(MSG), where members share information about
the EUMETCast reception hardware and software.
http://tech.groups.yahoo.com/group/MSG-1/
METOP
A forum for users of high-resolution AHRPT datafrom the MetOp satellite, available via
EUMETCast.
http://tech.groups.yahoo.com/group/METOP/
AVHRR
A forum for users who download high-resolution
EARS-AVHRR data from the NOAA polar orbiting
weather satellites via EUMETCast.
http://tech.groups.yahoo.com/group/AVHRR/ATOVSA Group for discussions about using ATVOS data.
Data from the whole world is available from
CLASS (www.class.noaa.gov) and for an extended
Europe, via EUMETCast.
http://tech.groups.yahoo.com/group/ATOVS/
Weather Satellite Reports
This group provides weekly reports, updates andnews on operational aspects of weather satellites.
http://tech.groups.yahoo.com/
group/weather-satellite-reports/
WXtoImg
Users of the WXtoImg software package for
capturing and imaging NOAA APT can air theirproblems, discuss its features and ask questions
about it.
http://groups.yahoo.com/group/wxtoimg-l/

www.geo-web.org.uk

The Editor is always delighted to receive
articles and images for inclusion in
GEO Quarterly. These can relate to any
aspect of Earth Imaging, especially *! ! !! ! &; 
hardware and software  !  <!
   >& Z  >  !   [  >& &
stations
 ]! ;  >; ^_  %> ` {
answerContributions should of course be original and,
where possible, should be submitted to theeditor in electronic format (floppy disc, e-mailattachment, CD, DVD). But of course we will
also accept handwritten and typed copy
should the need arise.
Please note, however, that major articles
which contain large numbers of satellite
images, photographs or other illustrations
should be submitted as early as possible, sothat they can be prepared and made up into
pages in time for publication.
Images and Diagrams
Images can be accepted in any of the major
bitmap formats: JPG, BMP, GIF, TIFF etc.
Images in both monochrome and colour are
welcomed. Line drawings and diagrams are
preferred in Windows metafile and postscript
formats. We can also scan original
photographs, negatives and slides.
Gridding, Overlays and Captions
Please note that readers’ satellite images
should be provided without added grid lines,
country outlines or captions unless these areconsidered essential for illustrative purposes
within an article.
If your article submission contains embedded
images and diagrams, please note that you
must also submit the individual, original
images, in one of the formats describedabove: these are essential for page make-up
purposes.
Submission of Copy
All materials for publication should be sent to
the editor,
Peter Green‘Hollowtree’
Eggesford, Devon EX18 7QX, England.
Tel:01769 580 700
The most efficient way to do this is as email
attachments to the following address
geoeditor@geo-web.org.uk

And finally . . .
if you do have material ready for the next
issue of GEO Quarterly, please submit it assoon as it is ready—do not wait till thedeadline above: this will simply create an
editorial log-jam and delay publication.

June 2011

Group for Earth Observation

GEO Quarterly No 30

Current Subscription Rates
United Kingdom ... £20

Europe ... £24

Rest of World ... £28

You can make your annual GEO Membership payment by any of the following methods:
 PayPal - Visit the GEO Shop website at http://www.geo-web.org.uk/shop.html and add your subscription to your basket
   >%> personal cheque or Postal Order made payable to 'Group for Earth Observation' > %direct bank transfer ! % &>  ! &%&  ] Your subscription is valid for one year from your date of application and entitles you to all the privileges
>>% _%;   ! & _` that your subscription will commence with the issue of GEO Quarterly that is current at the time of your !  ! ; %>%>_

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*!>  >% *& !   {Z^  > & ]

www.geo-web.org.uk

iii

GEO Quarterly No 30

Towards the end of February 2011 there
was relatively little cloud cover over the
Kamchatka
Peninsulaandtheillumination had improved considerably
since mid-winter. I have written for
GEOQ about the peninsula before, but
the image on the 24th was especiallyinteresting and – it has to be said – very
beautiful. Many of the volcanoes arevisible in this image but it is the western
coastline that is worthy of closer
attention. The temperature on the landiv

Group for Earth Observation

around the Sea of Othotsk varied aroundabout minus 21 degrees C. It looks as if
cold air was flowing down the contours
on the west of the peninsula where it
passed over the much warmer sea, at – 2
degrees C giving rise to coastal fog. The
warmed air rose and was cooled again,
but having picked up moisture over thesea the cooling condensed out to give aband of cloud (at around -13 degrees C)
running parallel to the coast. The
general picture in the Sea of Othotsk
www.geo-web.org.uk

June 2011

was of a south easterly air-stream
flowing off the ice which can be seen
breaking up towards the north of the
Sea. It might have been this that caused
enough wind sheer to create theinteresting vortices along the westernedge of the offshore cloud. This, anyhow,
is my amateur interpretation of theimage. I could be quite wrong, so it
would be interesting to hear an
alternative interpretation from anotherreader. Robert Moore

June 2011

Group for Earth Observation

GEO Quarterly No 30

USB Receiver Installation
Geoff Morris gw3atz@btopenworld.com
When a couple of years ago, I changed from the Skystar
internal card to the DVBWorld external USB receiver, theproblem arose as to where to have it. In the end it sat on topof my main PC with its cables strapped together. This reallywas not very satisfactory, as it tended to slide around. I
suppose I could have stuck it down, but never got round to it.!
I then thought of how I could tidy the whole thing up, being
somewhat fanatical when it comes to cables being neat andtidy. It occurred to me that it would be possible to install it
inside the PC.

Skystar 2 internal card replaced by DVBWorld receiver fixed to new back plate

To that end, I first used a blank plate from the back of the PC.
The type that is used for extra serial/USB ports etc. To fix it
to the plate, I decided after taking the board out of the case,that the best way to do it would be to take the nuts off theantenna sockets, and use them to fix the plate. This worked
well, but great care must be taken when undoing the nuts andalso when replacing. Do not over tighten. However I was not
pleased with the result, as the metal of the PC plate as fairly
thin, and tended to buckle when being drilled. So I made a
new plate from thicker aluminium, and the end result can beseen in the picture. Its still not perfect, but does the job.
As the USB port on the receiver is now inside the PC case, I
then had to decide how to connect it to the PC. I could
have used the original lead, taken it out of the case andback into its original USB port. However I decided that I
could take it directly to a USB header on the PC
motherboard. To do this I had to purchase a lead thatwould go onto the header. After a web search I found a
supplier for this,(Amazon) but could only get one with thenormal flat USB plug on it, so I bought an adaptor fromthe square socket on the DVBWorld box to a USB female
socket. This can be seen in the picture of the receiverinstalled inside the PC. The USB port I used on the PC
motherboard was different from the original. On starting
the PC, it found the DVB receiver as a new device andinstalled the drivers for it.
Overall I am pleased with the result. It is fairly easy to do,but if in any doubt as to how to carry it out, or how toconnect to your PC motherboard, leave well alone. I build
all my own PC’s so am aware of the motherboard connections,but please do not try this if you are uncertain as to how toproceed. There are other ways of doing this, and I have done
what works for me. BUT……….If in doubt DON’T.

www.geo-web.org.uk

23

GEO Quarterly No 30

Group for Earth Observation

June 2011

Francis Breame - vf0123@btinternet.com
Introduction
GEO Quarterly has covered the EnviHam project [2,7] in a
number of articles in recent issues. Briefly, this project allows
non-professional users to receive a selection of Envisat image
files in a similar manner to those broadcast by EUMETCast,using the Envisat Data Dissemination System (DDS) [6].

reasonable time. Press 'Launch VISAT' to start the viewer
with those files.
Please email me at the above address with any bugs,
comments, or suggestions. I’m happy to make changes ifthey’re feasible.

Caveats
These images are of particular interest because of their high      } x 1024, otherwise theresolution. For example, figure 1 shows the area around themain window will overlap. If there is a need for smaller
Strait of Hormuz; figure 2 is an enlargement of figure 1,
resolutions, let me know.
showing the artificial islands in Dubai; figure 3 shows the
Kennedy Space Centre and locality (the pads used by the           
Apollo/space shuttle launches are the Y-shaped feature on thedeposited by the DDS download software.
coast at the top centre).
    { 
arrangement based on multiple directories (say by year/
Licence holders can use the very comprehensive VISAT
month/day), you will have to keep changing the[5]
to view the files. However, one
software provided by ESA
directory via the menu. Again let me know.
problem I found was in locating the field of view of each image
file, as they are either very small or very long and thin. VISAT
does provide a world map showing the coverage of each file
Links and References
but unfortunately, although excellent for making use of the
1 Francis Breame's Web sitedata in the files, VISAT is very slow in opening them anddisplaying their coverage areas (at least on my computer). This
http://www.vf0123.btinternet.co.uk/
seems to be because VISAT decompresses and reads each file
2 EnviHam
in its entirety, and some of the files can approach 1 GB in
http://dwlinkdvb.esrin.esa.it/DDS/docs/Public_Docs/
size.
EnviHam_abstract.pdf
Thus, I wrote a simple front-end browser, EnviHamBrowse,
3 Envisat Operations
which displays on a world map the areas covered by the
http://www.esa.int/SPECIALS/Operations/
Envisat data. Files of interest can then be selected and VISATSEMOZY8L6VE_0.html
started automatically to display them in all their glory.
4
EnvisatDocuments
EnviHamBrowse can do this very quickly as it reads justenough of the file to determine its coverage area.
http://earth.esa.int/pub/ESA_DOC/ENVISAT/
5
VISAT/BEAM
Using EnviHamBrowse
http://www.brockmann-consult.de/cms/web/beam
EnviHamBrowse can be downloaded, together with a user
guide, from my Internet site [1]. Setup and full usage details
6 DDS Operations
are given in the user guide. The program is very simple to use,
http://dwlinkdvb.esrin.esa.it/DDS/welcome.html
so I’ll just give a brief overview of it here.
7 David Taylor’s notes on setting up EnviHam reception
http://www.satsignal.eu/wxsat/EnvisatDDS/
The screen is as shown in figure 4. The file to be displayed
can be filtered by date and/or type. At the moment, EnviHamtransmits three file types, which can be selected as
Cover and Back Cover Images
 *&**&`{*   *  >&  Envisat observes Saharan dust and plankton blooms.
Radiometer) level-1 gridded brightness temperature andEnvisat captures dust and sand from the Algerian Sahara
reflectance,
Desert, located in northern Africa, blowing west across ```` &{ `     
the Atlantic Ocean.
Spectrometer) level-2 reduced resolution geophysicalproduct,
Stretching across the eastern Atlantic, strong winds carry `|`&` &  }~     
the plume over the northwestern tip of the Iberian
coverage (although in practice there are a number outside
Peninsula (bottom), the western tip of France, theEurope).
southwestern tip of England (top right) and thesouthwestern coast of Ireland (top left).
On pressing 'Display directory', the coverage outline of thechosen files will then be displayed as shown in figure 4 (inDust from the Sahara Desert – the world’s largest desert,
this example, some of the passes overlap slightly). Eachencompassing around 8.6 million sq km – can beoutline has a tag, initially green, at the start of the pass.
transported over thousands of kilometres by atmospheric
Hovering the mouse over the tag gives details of the file.
convection currents. These convection currents form
Clicking it turns the outline to red and selects that file. Any
when warm, lighter air rises and cold, heavier air sinks.
number of files may be selected, but it is advisable not toContinued on page 42
chose too many in the interests of VISAT starting within a24

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Figure 1 - An Envisat MERIS full resolution imageof the Strait of Hormuz, acquired at 06:43 UT on March 3, 2011.

Figure 2 - A zoomed section from figure 1.

Figure 3 - An Envisat MERIS full resolution image showing Kennedy Space
Center, acquired at 15:40 UT on March 2, 2011.

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25

GEO Quarterly No 30

Group for Earth Observation

June 2011

Why I Succumbed To A Digital Satellite Meter
Francis Greaves – francis@choughs.net
I have been interested in Weather since I was about 10 years
old. I am still using the Stephenson Screen I built from a kit I
received on my 12th birthday. I have been receiving weather
satellites since about 1999.

I purchased a 1.2m dish and an LNB MTI (0.2db). My dish ison a tripod with wire round the bottom to keep the sheep off(Fig 1) and I have just under 20m of cable to get it into thehouse and feed my DVBWorld USB receiver.

My location since 2007 is a very exposed one at 51° 33.3'N 9°
37.7'W at an altitude of 60 m above sea level,ideal for weather.
I live in the countryside with sheep farms all around, and theneighbour's sheep to keep the grass down. I am on the northside of the Mizen Peninsula looking out across Dunmanus Bay
to Sheeps Head and into the Atlantic. I keep manual recordsof the weather and have three automatic weather stations
accumulated over time. (Fig 1) My internet connection iswireless from a small dish pointing at a mountain top with aspeed of 1 meg. This gives me a download speed of about 2.39
Mbps and upload speed of 0.46 Mbps. The dish is on thetallest mast in the background with my wind sensors on thesame mast. The highest being at about 10 m.

My computer setup consists of two Intel Pentium M 1.7GHz
with 1G RAM computers, one to purely receive Eumetcast, theother to receive Envi-Ham data. I have an Intel Quad Core
2.4GHz with 3G RAM to process the data and run my weather
stations. (see Fig 2 of work always in progress) I have a pair of
19” screens as twin for the Quad Core machine and the left
screen switching between all the computers. My weather
station data is displayed using programs I have written in
Java, Perl and Visual Basic. Most of this data is uploaded to
my website. I have a MYSQL Database on the site to store thedata. The satellite images are displayed using David Taylor's
excellent suite of software.

I am using an 80cm dish for Eumetcast reception which was
replaced recently. Sea air does rot dishes! When I saw thearticle by Francis Bell in GEO 25 and later David Taylor's
article in GEO 26 on the Envi-Ham project, I decided to havea go, despite being well out to the west and outside the 48dbW
footprint as shown in GEO 26.

26

I was accepted onto the Envi-Ham project in the middle ofJanuary, and returned my forms by email a couple of days
later. Then I heard nothing, so no software or key to start
receiving data. This was OK, because I just could not get mydish tuned in. The DVBWorld software is not the best to try
and set up the dish. To get the dish pointing correctly I used
an analogue meter to find Eurobird at 9° E. Then with a pairwww.geo-web.org.uk

GEO Quarterly No 30

Group for Earth Observationof two way hand held radios, and my long suffering wife
looking at the signal on the computer screen, I attempted tolocate Eutelsat W2A at 10° E. No problem finding Hotbird at
13° E, but I could not find Eutelsat. I had the software set to
the ANB (Arabic News Broadcast) as per David Taylor's article
in GEO 26. Nothing! We were by now nearly into March andstill nothing from ESA about my key and software. I finallyphoned Stefan Badessi, a delightful man, who was extremely
helpful regarding my lost email (I had sent several). They were
all in the spam bin. Finally that was sorted out and I got mykey, but still no signal from my nice big dish.
Desperate measures were called for. I decided to buy a Digital
Satellite Meter with Spectrum Display. Well they can be a bit
pricey to say the least! After a bit of searching I decided to get
a Horizon Digital Satellite TV Meter Plus with USB fromsatellitetv.ie from whom I had purchased my dish and LNB. It
arrived very promptly and turned out to be just the job. I wasable to adjust the alignment of my Eumetcast dish to give
about 5% improvement on the signal. The thing that caused
me the most problem was the LNB on my Envi-Ham dish. I
nearly sent it back, but Steve at satellitetv.ie asked me if I had
skewed the LNB to about 25° or so. I thought I had, but
decided to try again. As soon as I skewed the LNB well roundto about 45° I got a signal! (Fig 3) Fine tuning the dish was so

June 2011

much easier with my new meter than trying to convey signal
readings via the two way radio I would recommend it toanyone having problems of dish alignment, especially where
the signal is weak. I now have a 96% signal strength with 59– 60% quality (Fig 5).
I am now trying to get to grips with the data from Envi-Ham.
I am not able to receive all the images. There is signal loss
often mid to late morning, but I do get a diurnal dip in the
EUMETCast data signal, so I suspect this is the same problem.
I have included an early image processed in the Vista Beamsoftware using the MERISL1b 13,4,2 RGB filter. The pass wason 2011-03-14 at 11:32:06 to 11:35:12 (Fig 6)
I really do enjoy a challenge. I also enjoy overcoming the
problems. This sort of exercise helps keeps my 'Little Grey
Cells' active.
Links:ESA Envisat Website www.envisat.esa.it
Dish, LNB and meter www.satellitetv.ie
David Taylor's Site www.satsignal.net
Authors website www.choughs.net

Fig 1 Automatic weather stations & antenna farmFig 6 Early example of processing using Vista Beam softwareFig 2 The nerve centre!

Fig 3 LNB skewed to 45°

www.geo-web.org.uk

Fig 5 Readout from Horizon Digital
Satellite TV Meter

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GEO Quarterly No 30

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June 2011

The magic of multi-spectral imaging
James Brown
Many of us are by now familiar with the kind of image dataroutinely disseminated on EUMETCAST. From polar orbiters
such as METOP to the geosynchronous MSG fleet. Then there
are also the third-party relays from MODIS, which consist ofdata thinned by geographical area, resolution to an aggregateof 1km and to 18 selected channels out of the AQUA 36
channel raw data, as well as the AVHRR data from NOAA. Allof these can enable those with the right software to produce
composite images, and the often stunning near true colour
composites are the bread and butter viewing of so many of us.
But why are there so many other channels? Well the simple
answer is that the primary users ofmany of these satellites is themeteorological community, and forthem visual channels are only oneof many tools they need forsurveying the earth’s atmosphereand climatology. But here’s mychallenge to us – are you making
full use of all that great data?

The IR6.2 and 7.3 mm ones are good for water vapour
calculations and the 9.7 mm can look at ozone absorption etc.
etc.
We can then add or subtract these channels in varying
degrees, and by using the conventional RGB method of colour
combination we can assign a colour and radiance level to eachchannel to give an image which to the human eye accentuates
the aerosol content that we wish to discover. We can also
apply colour look-up tables (LUTs for short) that can assign
specific colours to desired radiance levels.

For me, although I mourn the lossof the days when soldering irons
were rarely cold, and equipment
was largely home brewed, one of
the most exciting things about ourhobby in recent years is that
thanks to the generous data access
we continue to enjoy, and thesoftware programmes that areavailable, mere amateurs likemyself can view in detail most of
the fascinating images that the
professionals use. We may nothave the depth of knowledge orunderstand all the physics behindthe use of some of this data, butwith the help of a few primers andin particular e.g. the excellent
software suite of David Taylor’s
GeosatSignal7, it is possible to get
so much more out of these multispectral imagers.
In the first place I want toconcentrate on Eumetsat’s MSG
dissemination – relevant for both theprime 0 degree longitude satellite ofMeteosat 9 (MSG-2) and the secondary Meteosat 8 (MSG-1) at
9.55 degrees east - now used e.g. for 5 minute rapid scantransmissions. Both these satellites give us access to 12channels of data, though MSG-1 is spatially limited to themore northern hemisphere. So what can be achieved?
Simply put – to get detailed information about what ishappening in the layers of the atmosphere we can need to lookat specific channels. On board each of the MSG satellites is an
optical imaging radiometer– or to give its full title - Spinning
Enhanced Visible and Infra-Red Imager. These SEVIRI
channels represent energy spectrum bands, 4 assigned to thevisible or near-infra-red bands, and 8 to Infra red channels. I
don’t want to get too technical with this article but to give you
an idea of why these channels were chosen – the NIR (nearinfra-red)1.6 mm is useful to discriminate clouds from snow,
and in combination with the two visible channels 0.6 mm and
0.8 mm, soil moisture and vegetation indices can be calculated.

28

Fig 1

Let’s give a simple example:
May 2010 went down in our recent history as the day planes
stopped flying in and out of Europe – because of the eruptionof the Icelandic volcano, Eyjafallajokull. But how did thatshow up on the MSG imaging? On the visual channels aplume of white steam was visible during the day, but as it
became mixed with cloud it was soon hard to discriminate
the ash signature. However, by using the SEVIRI channels
8.7, 10.8, and 12.0 mm in combination the ash particles,
sulphur particulates etc. could clearly be seen. (see fig1).
Clearer examples are available from the MODIS data stream,
but the great advantage of MSG-2 is the animations which
can so easily be made, and hence the strength of theemissions and their direction are easy to spot. Fig1 wastaken on May 6th 2010. But there are many more potential
eruptions due and not just from Iceland. This remarkableability to discriminate atmospheric pollutants will be there
for us follow the next one.

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But in the mean time, ourgenerally benign atmosphereinteracts with the earth surface,and occasionally a storm over the
more desert landscape will scour
the land and lift vast clouds ofdesert dust and sand high into thelower atmosphere. An intense oneon April 15th 2011 had dust
plumes extending from thewestern shore of the Persian Gulf
to the eastern shore of the CaspianSea. Shown in fig 2 the dust is
thickest over northern Saudi
Arabia, southern Iraq, andKuwait—Once again by judicious
channel selection of the samechannels, but in a different
combination we are enabled topick out the dust from otheratmospheric processes.
And once again animations canreveal the motion of the dust
cloud and track its thickness andspatial extent.
Fig 2

Then again there are so many more great possibilities withthese data channels. Fog can be particularly hard todifferentiate as it lurks in the lowest boundary layers of thecomplicate things night time fog and day time fog exhibit
different signatures to the sensors. I have been experimenting
with this just recently, and although the colour is perhaps not

Fig 3

atmosphere and is often not far in temperature terms from thesurrounding ground. It can also become freezing fog and when
the sun gets to work on it the fog may transform into low levelstratus, and again the difference between the two is extremely
hard to detect even with satellite imagery. And just to

the most suitable I could separate fog from low cloud in theimage below. The fog is the brown colour in the western Italian
Po valley and also in the SE of France. You could see it
gradually burn off as the day progressed. Why not see if you
can do better?

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June 2011

Another use is in detectionof ice and snow. Fig 4
taken from data on April
30th 2011 shows detail of
sub-zero data in pale blue
– the semi-permanentsnow and ice along thespine of Scandinavia canbe seen – as can theremnants of the Baltic
ice. Effective as theseresults are, the fullpotential is realised withimagery that has greater
resolution at the subsatellite point.
The next fig shows thesame area but viewed
with David Taylor’s L1
MODIS viewer. This has anumber of presets andone of them is for snow –set for RGB521 the snow
cover is clearly revealed-and even this image is
not at full resolution.
But practically speaking– how can we arrive atthesereallyusefulimages? Well, there is a
hard way and an easy
way. The hard way is tosavethechannels
separately and importthem into a high-end graphics package, and there manipulate
the relationship between the images. The much easier way is
to let a processing package do the hard work. I have used acouple of different image processing packages in the past
including Rob Alblas’s xrit2pic and they perform admirably.

30

Fig 4

However I am an unashamed advocate of the latest iterationof David’s GeosatSignal7 program suite for ease of use andflexibility.

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Fig 5

June 2011

Group for Earth Observation

GEO Quarterly No 30

The image shown here has theprocessing tab open, revealing accessto the various preset and user definablesettings. After selecting the RGB option
under false colour all the settings
controls become accessible and by
assigning images to the RGB channels
they can then be combined and alteredto achieve the desired display. There
are several useful primers available
courtesy of Eumetsat, (see thereferences at the end) and these canmake the learning curve a much easierproposition.
There is not the time or space to giveevery example in this rich vein ofsatellite processing, but I just wanted
to whet your appetite and if you reallywant take MSG to the max – take a lookat the air mass image of fig.7
This takes us much deeper into those atmospheric processes
which are at the heart of our weather. By careful use of thewater vapour channels in particular, whole layers of theatmosphere can be studied. For example the bright orange
detail is very dry air – here shown entrained into a depression
centred east of Italy . Another dry slot is marking the boundary
between warm moist Atlantic air and much colder Arctic air
pushing down from Newfoundland, both areas of highpotential vorticity. The green areas are warm ozone poor air,and the blue cold ozone rich air. By examining these features
meteorologists both professional and amateur can see moreclearly significant upper-level flow features including jet
streams.
There is enough material under this subject to keep us
viewing and interacting for a long time to come, and withDavid’s software RGB settings are now there as text files thatcan be edited and shared with others. With all this delving
comes an expansion of knowledge and a better understandingof what is happening in the air above us , the ground beneathus, and the oceans around us. I am hugely indebted to
EUMETSAT and others for all the help that is so freely on
offer.

Fig 6

References:
An introduction to the MSG SEVIRI instrument:
http://www.eumetsat.int/groups/ops/documents/document/pdf_ten_
msg_seviri_instrument.pdf

Many more can be found from the main Eumetsat document
web site and the ones below
Highly recommended Powerpoint primers:
http://oiswww.eumetsat.org/WEBOPS/msg_
interpretation/PowerPoints/Channels/IntroRGB.ppt
http://oiswww.eumetsat.org/WEBOPS/msg_
interpretation/PowerPoints/Channels/Channel_IR39.ppt
http://oiswww.eumetsat.int/~idds/html/doc/best_practices.pdf
http://oiswww.eumetsat.int/~idds/html/product_
description.html

Fig 7

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GEO Quarterly No 30

Group for Earth Observation

June 2011

Quarterly Question 30
Francis Bell
Regular followers of the Quarterly Question will haverecognised my interest in the area of the Indian Ocean
containing the islands of Mauritius, Madagascar and theadjacent coast of east Africa. My interest in this area was
because of my visit there in December 2010 / January 2011.
Nadine and I had booked a cruise starting in Mauritius andfinishing in Mombassa. As usual, I took my APT equipmentwith me and received some interesting NOAA 19 images, oneof which was published in GEOQ 29.

Eratosthenes had also recorded the angle of the sun at noonin Alexandria on the same day as it was shining down a wellin Aswan. With this small number of observation
Eratosthenes was able to calculate the circumference of the
Earth producing a figure very close to today’s accepted value.
The Question
If the circumference of the earth is 40,000 km and the
distance from Aswan to Alexandria is 900 km what would be
the elevation of the sun at noon in Alexandria on the same
day that the sun shone down a well in Aswan; that is, when
the sun’s elevation in Aswan was 90°?
Notes
Eratosthenes did this calculation the other way round,measuring the sun’s angle and then calculating thecircumference of the Earth.
Also, Alexandria is not exactly due north of Aswan but it isquite close; and Aswan is not exactly on the tropic ofCancer but again quite close. And for good measure theEarth is not a perfect sphere.
Answers to the nearest whole degree, please, to Francis
Bell, by email tofrancis@geoweb.org.uk

or by post.

Prior to the start of the cruise, we stayed for four days on theisland of Mauritius, and for the most part we had hot sunny
weather with clear skies. I noticed that each day at noon thesun was overhead. I became intrigued with the sun’s
elevation and recognised that, at our latitude of 22°south
and just seven or eight days after the December solstice,
the sun would be very close to overhead at noon each daywith an elevation close to 90°.

Francis standing in the sun with his shadow directly beneath. Not
necessarily an accurate measurement of sun angle because
humans can lean several degrees from the vertical and still stay
standing. A piece of string and a weight (plumb line) was judged
more accurate.

To confirm this, I tied two of my long shoelaces together
and attached a weight at one end. Hanging this in thesunshine allowed me to measure the length of the laces’
shadow and hence, by calculation, the elevation of the sun.
The shortest shadow I recorded was at 12.18 pm local timeon January 2 when the shadow from my laces (which were
one metre in length) was 14 mm long. For a solar elevationof 90°, this measurement would of course have been zero.
However, the calculation of
90 - sin (15/1000)

gave the sun's elevation as 89.2°, not quite vertical but
near enough to shine sunlight down an open well! What
has a well to do with my interest in the sun’s elevation?
The Hellanistic Dimension
I remember reading some accounts of the classical scholar
Eratosthenes (276 to 195 BC). Part of his work related tothe sun and his calculation of the Earth’s circumference.
He observed that, on one day each year, at the summer
solstice, the sun would shine directly down a well in Syene(now Aswan). But on that same day this did not happen in
Alexandria, some distance to the north. Legend has it that
Eratosthenes was so intrigued with these observations thathe sponsored someone to measure the distance between
Aswan and Alexandria. The result was a distance of 5,000Hellenic stadia which is believed in today’s units to equal
about 925 km. You can check this distance on a suitablemodern map.

32

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June 2011

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GEO Quarterly No 30

Esko Petäjä
GeoSatSignal is an excellent tool for combining weather
satellite data, and is widely used to create composite images
from two or more Meteosat channels. But the program canalso handle data from other sources. For example, it ispossible to combine satellite images with other data like ~>~   [1] ~>  
 Blitzortung.org Europe overlays [2]       #This article explains how weather satellite data can be
combined with aircraft flight position data. This interests me
because I am a Private light-aircraft pilot and need to knowthat planes will have a safe flight, and not hit bad weather.
In the first part of my article, I will concentrate oninternational flights. My project has been developed together
with David Taylor, who has extended GeoSatSignal [4] toprovide a calibration point for the Plane Plotter software [3].
This was a great help and essential to the success of thisproject. I have noticed that there are several HAM-Radio
operators within GEO and this article includes also, some
HAM radio perspective.

Figure 1 - International flight position data combinedwith a Meteosat-9 HRV (channel-12) image

Station Setup
My station consist of the following components.
 *EUMETCast receiving system
 MSG DataManager, GeoSatSignal and MapToGeo * |*  # * |` {&`}
 &``  < PC HFDL software from Charles Brain Plane Plotter software from NOAA.

Data Flow
The data flow in my system is as follows (figure 2).
 MSG DataManger notification starts GeoSatSignal usingcommand line parameters *GeoSatSignal Job provides update charts for Plane
Plotter and Chart calibration files
 *>     >Blue Marble
data using MapToGeo
 PC HFDL provides aircraft positions to Plane Plotter Plane Plotter then saves a picture every 15 minutes.

Figure 2 - System Data Flow

Station Diagram
My station consists of the following, shown schematically infigure 3.
 *EUMETCast receiving system with GeoSatSignal
providing the data for Plane Plotter * |   {  &`}`  *    PC HFDL *&   Plane Plotter.
Figure 3 - The Station Diagram

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33

GEO Quarterly No 30

Group for Earth Observation

June 2011

Position Reporting System for International Flights
The position reporting system for international flights is basedon SATCOM satellite communication or on HFDL (an HF datalink protocol). These systems are operated by AeronauticalRadio Incorporated (ARINC). HFDL coverage provides a highly
cost-effective data link capability for carriers on remote oceanicroutes, as well as the high latitude polar routes, where
SATCOM coverage is unavailable. HFDL is costs less than
SATCOM, and many carriers are using HFDL instead of satellite
services, or as a backup system.

Figure 4 - HFDL Ground Station Locations in Europe

HFDL is still the only data link technology that works over the
North Pole, and provides continuous, uninterrupted data linkcoverage on the popular polar routes between North America
and eastern Europe and Asia. There are 16 HFDL groundstations covering the globe. In Europe (figure 4), there arestations in Iceland (Reykjavik), Ireland (Shannon) and the
Canary Islands. Figures 5 and 6 illustrate a typical groundstation antenna system and the receiving antenna on an
aeroplane.
Receiving Aircraft Position Data
I use the SDR-14 software-based radio to receive signals fromground stations. This radio has excellent software, including
spectrum and spectrogram displays. Figure 7 shows thereception spectrum and the squitters sent every 32 seconds inspectrogram display.

Figure 5 - An HFDL Ground Station Antenna in Panama

Prediction of correct receiving frequency
HFDL uses a variety of different HF frequencies (all below
30 MHz) according to the time of day. The frequency selected
depends upon the conditions within various atmospheric layers.
Figure 8 illustrates the atmospheric layer effect oncommunication. The easiest way is to use a higher frequency
during daytime and lower one at night. I use following
procedure to check the availability and frequency of groundstations.
   VOACAP HF propagation program to selectthe correct frequency to be used (VOACAP is an HF
frequency planning system used by Voice of America intheir frequency planning)  > >{~   
special version of his web based program *        PC HFDL
reports the frequencies used by other stations. Using thisinformation, I can change to the frequency of different
stations.

Figure 6 - The HFDL Antenna on an Aeroplane

Figure 8 - How the atmosphere affects communications

Figure 7 - The Spectrogram Display

34

Decoding HFDL
Decoding of HFDL is done using the PC HFDL program whichruns on a dedicated PC and writes log files for Plane Plotter.
HFDL uses phase shift keying (PSK) at data rates of 300,
600, 1200 and 1800 bps, the rate used being dependent on
the prevailing propagation conditions. Connection between
the radio and the software in made through a sound card or
a virtual audio cable. Figure 10 shows the screen output asPC HFDL decodes flight positions, and shows the active
ground stations and their frequencies.

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June 2011

Group for Earth Observation

GEO Quarterly No 30

Making Backgrounds for GeoSatSignal
I use the MapToGeo program to develop backgrounds for
GeoSatSignal, based on 2-km/pixel Blue Marble images fromNASA. I generate three different types of background, one for
FSD, one for HRV and a third for HRV-north. Using
MapToGeo is quite easy.
From the menu bar, load a 2-km/pixel
Mercator Blue Marble image, then click on
the <Remap to> option to display a dropdown menu of mapping options. Part of thislist is illustrated in figure 9, where my threepreferences are highlighted.
MapToGeo default file names could be used.
Files are saved in same directory where
GeoSatSignal.exe is located.

Figure 9

Scripting in MSG DataManager and GeoSatSignal
Automation and scripting requires the following actions:Figure 10 - The PC HFDL Screen Output

 *       
MSG DataManager
 MsgNotify.bat will be called after each end of scan MsgNotify.bat will start the required GeoSatSignal Job inbackground mode.
Using Plane Plotter
There are multiple possibilities for using Plane Plotter but,until now, I have been working with three different user
scenarios. There is easy chart selection in Plane Plotter.
 *  GeoSatSignal to Plane
Plotter }  `  }
 Blue Marble background   #Chart Calibration
Chart calibration needs to be done so that Plane Plotter
understands coordinate systems on weather data. Plane
Plotter has manual calibration, but this is very timeconsuming, and the 'automatic calibration points' feature of
GeoSatSignal is great help. Calibration points are generated
according to the selected projection and area in the
GeoSatSignal Job.

Figure 11 - Visible Chart (HRV Channel 12)

Different Chart Types
Different chart are used for different scenarios: a visible
chart show planes in standard Wefax presentation, a Blue
Marble background is useful for showing planes during
daytime, while the cloud top option shows if planes arehitting dangerous weather. There are also many otherpossibilities but I have not yet had time to work these otherscenarios out. As soon as I have time, I plan to work for
different cloud type and fog detection. Additionally, atpresent, I work using a fixed area defined by a GeoSatSignal
Job. If I need more positional accuracy, I zoom in manually.
I have also tested the possibility of having a dynamic area,
where remapping is done according the real-time plane
position. Plane Plotter has an interface which gives the
position for a selected plane and I can use this position as
parameters for remapping. Figure 11 shows planes plottedon a Visible chart (HRV Channel 12), figure 12 on a Blue
Marble chart, while figure 13 shows planes approaching the
UK on a Cloud Top chart.
Time Based Output of Plane Plotter
Plane Plotter offers the possibility of generating an output file(GIF) or video (AVI) according to defined intervals, andincluding weather data and plane positions.

www.geo-web.org.uk

Figure 12 - Blue Marble Chart

35

GEO Quarterly No 30

Group for Earth Observation

Figure 13 - Planes approaching the UK plotted on a Cloud Top Chart

By using such an animation, the progress of aflight can be generated.
Figure 14 shows Finnair flight AY 1516 bringing
tourists back from the Canary Islands after asuccessful holiday.

References
1 Blue Marble
http://earthobservatory.nasa.gov/Features/BlueMarble/
2 Blitzortung
http://www.blitzortung.org/Webpages/index.php
3 Plane Plotter
http://www.coaa.co.uk/planeplotter.htm
4 GeoSatSignal
http://www.satsignal.eu/software/geosatsignal.htm
Figure 14 - Tracking a Finnair holiday flight36

www.geo-web.org.uk

June 2011

June 2011

Group for Earth Observation

GEO Quarterly No 30

Record loss of ozone over Arctic
John Tellick
ESA’s Envisat satellite has measured record low levels ofozone over the Euro-Atlantic sector of the northernhemisphere during March.
This record low was caused by unusually strong winds,
known as the polar vortex, which isolated the atmosphericmass over the North Pole and prevented it from mixing with
air in the mid-latitudes.
This led to very low temperatures and created conditions
similar to those that occur every southern hemisphere
winter over the Antarctic.
As March sunlight hit this cold air mass it released chlorine
and bromine atoms – ozone-destroying gases that originate
from chlorofluorocarbons (CFCs) and break ozone down into
individual oxygen molecules – predominantly in the lower
stratosphere, around 20 km above the surface
Ozone is a protective atmospheric layer found at around 25
km altitude that acts as a sunlight filter shielding life on
Earth from harmful ultraviolet rays, which can harmmarine life and increase the risk of skin cancer andcataracts.
Stratospheric temperatures in the Arctic show strong
variations from winter to winter. Last year, temperaturesand ozone above the Arctic were very high. The lastunusually low stratospheric temperatures over the North
Pole were recorded in 1997.
Scientists are investigating why the 2011 and 1997 Arctic

winters were so cold and whether these random events are
statistically linked to global climate change.
"In a changing climate, it is expected that on average
stratospheric temperatures cool, which means morechemical ozone depletion will occur," said Mark Weber fromthe University of Bremen.
"On the other hand, many studies show that the stratosphericcirculation in the northern hemisphere may be enhanced in
the future and, consequently, more ozone will be transported
from the tropics into high latitudes and reduce ozone
depletion."
Answering this question requires more research on ozone
modelling and ozone trend monitoring, which is only
possible because of the historic satellite data on record.
ESA’s Climate Change Initiative Programme has a project
dedicated to this research.
"Measurements from the Envisat’s Sciamachy, MIPAS andGOMOS instruments are providing unique ozone informationthat is important in enabling scientists to separate chemicaland dynamical changes and helping to identify the influenceof climate change on the stratosphere. It is, therefore,
essential to keep these instruments measuring for as longas possible," said Weber.
Banned under the Montreal Protocol, CFCs have still not
vanished from the air but are on the decline. Nevertheless,strong chemical ozone depletion will continue to occur inthe coming decades during unusually cold Arctic winters.

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37

GEO Quarterly No 30

Group for Earth Observation

June 2011

John Heath

Now you See it Now you Don’t
Geo readers will know that sun angle makes a significant
difference to the appearance of ground features. I had thisillustrated perfectly on a field I can see from my home.

Date: March 21st 2011 Place: Cornworthy Devon
Time GMTSun Azimuth
Sun Elevation

There is a difference in the appearance of the grass on theslope, rough and un-grazed, compared with the top where it isgrazed but the recently erected post and wire fence is invisible
at sun angles above about 30 degrees. At low sun angles it isvery prominent.

1615
245
20.4
1715
258
11.2
1747
264
6.6
1759
266
4.5
1809
268
2.8
1815
269
1.8
Sun going behind nearby hills
You will notice quite a bit of haze in the first picture which isalmost cleared an hour later. It’s not the haze that obscuresthe fence in the first picture.

I decided to take a short set of images and co-relate them with
the Suns position. (Taken from my satellite tracking software).
The digital camera was set up and left in place and I took ashot from time to time. I might try another series at precise
intervals then compare the images.

38

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June 2011

Group for Earth Observation

GEO Quarterly No 30

Nigel Heasman - www.nigelheasman.com

Fig1 Maronite fields

Winter is now almost past and we have been enjoying somelovely spring-like days, with lots of flowers appearing over thelast few weeks. As I write, in early March, we are in the 'yellow
phase', with the gorse in bloom and scenting the air wonderfully.
Although we have not had a lot of rain over the last few
months, there have been some quite dramatic thunderstorms.
Sadly, the reservoirs are still only about two thirds full—in
previous years they had been overflowing by this time. The
problem is that it has been the 'wrong sort' of rain! Most of therainstorms have been brief and heavy and a lot of the waterhas run off the surface and down to the sea instead of finding
its way to the reservoirs either via the streams or theunderground aquifers,. The sea then takes on a very muddy
look for up to a mile off shore. The amount of rainfall so far
this year has been well below average, as you can see fromfigure 2.
The coastline of North Cyprus is mostly rugged and rocky,
with only a few sandy beaches. The caves at sea level are afavourite breeding ground for the monk seal
http://en.wikipedia.org/wiki/Mediterranean_Monk_Seal

and, although their numbers are declining due to expanding
human activity, there is still a small population living here
(figure 3 and above).
A couple of miles westwards from my home there is a very
fertile area where a Maronite community live and work.
http://www.maronitesofcyprus.com/cgibin/hweb?-A=841&-V=history

These are very hard-working people and the crops growing
there are a tribute to their skill and industry. Almost every
available patch of land has been cultivated (Fig.1). By the lookof it, the crop will be ready to harvest in a couple of months(mid May) and then the area will slowly take on a brown anddried-up appearance for the long hot summer. The soil there
becomes very sticky after a rain shower but soon dries up
when the sun comes out. This is one of my favourite dog
walking areas, with only the sound of the insects and thebreeze in the crops to disturb the peace and quiet.
During early March, a deep low pressure area was centred
over this part of the world and it brought a marked drop in
temperature by drawing cold air down from Russia, the BlackSea and central Turkey. One night we had a dramatic
thunderstorm along with over 8 mm of rain in an hour.
It shows up quite well on the picture (Fig.4) which is a MSG
HRIT channel 9 image enhanced with false colour (using
GeoSatSignal and LutLandSea-r2b ) to show the cold cloud
tops. The air temperature has dropped from a respectable 15C
a couple of days ago to 4.3C last night! One advantage thoughis that the cooler air has cleared the haze and now themountains in the south of Turkey (Fig.5), approx. 50 miles
away, are clearly visible with their snow covered peaks.
Speaking of Turkey and water, I read in the local English
language newspaper (Cyprus Today) that the pipeline project,
to bring water from southern Turkey to North Cyprus, has atlong last actually started. The Prime Ministers of Turkey andNorthern Cyprus recently attended a ceremony to lay thefoundation of the new dam at Alakopru, in Anamur, southernTurkey. The pipeline, 107 km long and suspended 250 metres
under the sea, will be capable of transporting 75 million cubic
metres of drinking and irrigation water annually. Anotherinteresting fact to emerge is that the new dam will also be
used to generate electricity which will be carried to the island.

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GEO Quarterly No 30

Group for Earth Observation

The project completion date is anticipated to be in 2014.
A sure sign that spring is here is the arrival of migrating
swallows, en route to northern Europe for the summer.
There must have been dozens flying around in their gracefulfashion, catching insects on the wing. Normally arriving inearly March, they were a little late this year, delayed no doubt
by the cool weather.

June 2011

New leaves are appearing on the grape vines and the orange
tree blossom has started to show—a wonderful example of theever changing seasons.
That's about all for now, from the Turkish Republic ofNorthern Cyprus— the sky has cleared, the temperature isslowly rising and, with the sun shining all and every day, theneighbours pool will soon be warm enough to swim in.

Fig 2 - Rainfall Graph

Fig 3 Coastal view of Monk Seal areaFig 4 MSG HRIT channel 9 image enhanced with false colour (using
GeoSatSignal and LutLandSea-r2b)

Fig 5 Map showing the distribution of the Mediterranean Monk Seal

Fig 5 Mountains in the south of Turkey

40

Figure 6 - Local mountainwww.geo-web.org.uk

June 2011

Group for Earth Observation

GEO Quarterly No 30

Douglas Deans – dsdeans@btinternet.com

When it comes to plans to upgrade our computers how often
do we concentrate on improvements to the computer itself orindeed the keyboard or mouse. It surprises me how frequently
the monitor is relegated to the bottom of our list despite thefact that it is our visual link to what is going on. It is very easy
to make our eyes tired or indeed to damage them and yet
many people are still using old CRT monitors with theirdistorted and aging screens which must make the whole
computer experience a less enjoyable one. I changed to LCD
technology many years ago and as is often the case, once
done, I wished I had changed much earlier. The difference isunbelievable. Crisp clean images and every pixel perfect on
the whole of the screen. No edge distortion to strain the eyes
and the added bonus of much cheaper running costs. Old
worries, back in the early days of LCD monitors, about refresh
rates are long gone and even the issue of dead pixels has been
greatly reduced. I have had 3 LCD monitors not because ofany problems I hasten to add, but simply my desire to increase
screen size to view those high resolution images and animations
from my Eumetcast system. Incidentally I have never had aproblem with dead pixels on any of my monitors.
The life expectancy of LCD far exceeds that of the CRT monitor
although I accept that nowadays the pace of technology moredictates our updating habits.
So perhaps it is time to give your eyes a treat. LCD monitors
are now relatively cheap even for larger screen sizes and goodquality widescreen 22 inch monitors are available for wellunder £200 or just a couple of pairs of glasses !
I was asked sometime ago for an explanation of the term deadpixels. In fact there are two terms used to describe pixel
problems. Dead and Stuck Pixels. This, of course, is only
relevant to LCD monitors.
To understand how pixel problems develop in an LCD monitor,
it is important to have a basic understanding of the underlying
technology of the LCD monitor. Unlike CRTs that are actively
generating the light through phosphors, an LCD actuallytakes white light and filters it to get the desired colours. To dothis for each given pixel, three sub pixels are defined for red,green and blue light. When the sub-pixel is off, the filter will
block the specified colour of light. When the sub-pixel is on, it
will open the filter to let a desired amount of light through.
A dead pixel is defined as a pixel or set of sub-pixels that has
failed and is permanently in the off position. This conditionmeans that the pixel will not let any light through. This can beobserved as a dark or black spot on a brightly coloured or
white background (but obviously not seen when the screen isblack). Dead pixels are quite rare and are less noticeable tothe user.
A stuck pixel is defined as a pixel or sub-pixel that has failed
and is permanently in the on position. This can be either witha single or multiple sub-pixels for a given pixel and is best
observed on a dark or black background. A white pixel means
all three sub-pixels have failed while a green, red or blue pixelmeans one of the sub-pixels has failed.

Some people do wonder why pixel defects are allowed but it issimply unreasonable not to expect occasional occurrences.
Perhaps another way to look at it is that a guarantee of nodead or stuck pixels would make the cost prohibitive. We must
remember that LCD panels are very complicated devices to
put together. Each pixel in an LCD monitor is controlled by anumber of transistors embedded into sheets of material. For
example, a 15” LCD with a resolution of 1024x768 has
786,432 pixels comprised of 2,35,9296 sub-pixels, and that is
a lot of transistors! Monitors with higher resolutions will havean even greater number of pixels. Even a small impurity in thelayers that make up these pixels can result in a pixel defect.
If the manufacturers were to throw out every panel that evenhad a single defect, the cost to produce LCD monitors would
be so high that no consumers would be willing to purchasethem. To help them financially produce the panels, themanufacturers have defined a certain percentage of pixels thatcan be defective but still allow them to sell the panel. This
percentage is extremely small, equating to under 1/100th of apercent of the total number of pixels. With improved
technologies and techniques, the number of panels being
produced with defects is dropping and as I mentioned earlier
I have not experienced a single pixel issue on any of my three
LCD monitors or indeed any of my LCD televisions.
Manufacturers have their own replacement policies for LCD
monitors and those vary from one producer to another, so it isimportant to read their policy with regards to what number ofstuck or dead pixels are allowed before the unit can be
returned. There is a further complication because somemanufacturers not only refer to the number of dead pixels but
also their location and those parameters can vary with the size
and model of the monitor. Clearly a cluster of dead pixels will
look worse than a few scattered throughout the whole screen.
By the way just be sure that it is a pixel issue and not a fleckof dust (or worse !) on the screen. It is amazing how similar thetwo can look and it would not be the first time that I havewiped away a dead pixel !
In addition to the manufacturer warranty, look at the
replacement policy of the retailer that you are purchasing themonitor from. It is very likely that the policy of the retailer may
be better than that of the manufacturer allowing anotheravenue if the newly purchased monitor has a number ofdefective pixels.
So to summarise it is very important to be a well informed
consumer when purchasing an LCD monitor. Research thewarranty and replacement policies from the manufacturer andretailer before making a purchase. Be sure to understandwhat the terms of the different types and locations of pixel
defects mean. All of this can help alleviate frustration if themonitor that you purchase does not meet your standards ofquality.
Regular readers will know that I have been detailing channel
by channel, file and data types sent through the Eumetcast
system. So far I have looked at Channels 1, 2, 3, 4 and 5. This
quarter I want to look at one of the EPS channels, as I would

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GEO Quarterly No 30

like to concentrate initially onchannels most likely to be of interest
to amateurs. In due course I do hopeto eventually complete all channels
but it is quite an undertaking andmany of the channels have non image
data only of interest to professionals
and in particular those involved in
Nowcasting. So this quarter I will lookat channel EPS-10.
I have the usual list of latest programsfrom David Taylor and also a newprogram from the pen of Francis
Breame specifically for those involved
with the EnviSat project. So please
read on.
EPS-10Firstly some background information
about the EPS system. The Eumetsat
Polar System (EPS) is Europe’s
contribution to a joint European and
US operational polar satellite system
where Europe covers the mid-morning(AM) orbit and the US covers theafternoon (PM) orbit. Metop (although
jointly developed) is the European
satellite which delivers high resolution
sounding and imagery products inglobal coverage.
The data provided by Metop (andsome of the NOAA data) is distributed
through Eumetcast in channels
prefixed by EPS. There are currently
17 active EPS channels.
EPS-10 is one of the most fascinating
channels and provides two data types.
Probably the most interesting toamateurs is the full resolution, 5channel global HRPT data which isquite stunning. As each orbit data is
downloaded at the Svalbard receiving
station this data is about 115minutes
delayed. Do remember that this isglobal data. Of course as we havealready dealt with in previous journals
there are other Eumetcast services
which provide the European subset of
this data more timeously. By the way
at the time of writing, Eumetsat haveplans to carry out tests using anotherstation at McMurdo in the Antarctica
which should improve the timelinessof the global data to about 65 minutes.
Here is an example of the typical file
type provided for the global AVHRR
service on channel EPS 10.
AVHR_xxx_1B_M02_2011041519490
3Z_20110415195203Z_N_O_201104
15211404Z
Each file is approximately 28MB insize.
One of the great advantages of global
HRPT data is that we are able to see
fabulous images and fascinating
meteorology in parts of the world notnormally available to us. I find some42

Group for Earth Observationof the South Pole images justbreathtaking and when the sun is low
it provides the further advantage offascinating topography. As an exampleof this GDS data, I have included animage of the South Pole taken on the
31st October last year as Antarctica’s
summer approached.
The Ross Ice shelf and Murdoch Sound
predominate the image which is shownon the inside back cover.
The second data type on this channel
is the Polar Winds from Metop providing
winds at all heights below thetropopause in the polar regions(latitudes higher than 55º). This data isderived from the Metop AVHRR
instrument IR 10.8 channel and eachfile is provided in bufr format. A typicalfile takes the following form.
avhrr_20110415_222803_
metopa_23289_eps_o_amv.l2_bufr
There are approximately 150 files perday.

Program Updates.
EnviHamBrowse Version
0.1.2110326 by Francis Breame.
Many folk will have heard of the
EnviSat project which has beenreviewed and discussed in a number ofprevious quarterlies. I have not, as yet,applied to be part of the project, so I
am not able to properly test or review
any software associated with receiving
this data.

June 2011

ATOVS Reader

v 1.2.2

AVHRR Manager

v 2.0.6

BUFR Viewer

v 1.1.8

CMA Viewer

v 1.2.0

DWDSAT
Viewer

HRPT v 1.2.4

GeoSatSignal

v 7.2.2

GRIB Viewer

v 2.3.10

GroundMap

v 2.1.6

HDF Viewer

v 1.4.4

HRPT Reader

v 2.10.0

Kepler Manager

v 1.4.2

MapToGeov 1.1.8

Metop Manager

v 1.4.8

MODIS L1
Fire Viewer

v 1.0.4

andMSG Animatorv 2.5.46

MSGData
Managerv 2.5.46

PassControl

v 3.2.4

SatSignal

v 5.2.2

Sea-Ice
Viewer&

SST v 1.4.2

However I know that Francis Breame
hasrecently
writtensoftwarespecifically to speed up opening of
coverage files (see page 24). It has beenreported that VISAT which is the ESA
supplied file viewer can be rather slow
in opening files. To help alleviate thatproblem Francis has written a frontend browser (called EnviHamBrowse)
to speed things up and allow a quicker
selection of which files you wish toopen and view in VISAT. Once again
this is a free download from Francis’
pen.

Wxtrack

To learn more about the program anddownload the latest updates please go
to :-MERIS acquired this image on 8 April
at a resolution of 300 m.

http://www.vf0123.btinternet.co.uk

David Taylor’s programs (latest
releases).
Just a reminder that the list below isfor fully tested releases and does notinclude the latest beta (or alpha)versions currently on test. Those canalso be downloaded from David’s site.
http://www.satsignal.eu

www.geo-web.org.uk

v 3.8.12

Cover and Back Cover Images
Continued from page 24

In this image, plankton blooms arevisible in the Atlantic as blue andgreen swirls. (The various shades ofgreen and tan in the English Channel
and around Wales are due tosediments being transported in thewater.)

Credit ESA.
Back cover Image
New Zealand December 3rd 2010
from Metop A received via EUMETCastand using the vegetation tab of David
Taylor's HRPT Reader

Mike Stevens

You might say: 'not again'. Yet another new system to sortout. But that’s what our hobby is all about: trying to achieve
results that only professionals can aspire to—and in mostcases we can, and do.
On that basis, I felt that Envisat DDS just had to be looked
at, so my journey began. It was the publication of thepictures in GEO Quarterly that caught my eye. They werestunning and I thought that was something most amateurs
would love to achieve. So I am going to give it a try.
The first part of the process was to contact the Envisat DDSteam and apply for a licence, which I did. The response byemail was very quick indeed, enclosing several documentsthat need to be read carefully, as well as an application form
to gather information on yourself and your station. Once thatwas completed, I returned a copy by email and posted theoriginal by first class airmail. Again the response was very
quick indeed.
What followed was an email with six PDF attachments which
I would advise you to read immediately. One of the
documents (APP-ADU–0102-029 Iss3-0 RXPC Rqmts) needs
a reply about all the local details of your station andequipment, quoting IP addresses and MAC Codes for thereceiver. These are required to enable the DDS Team tosupply you with a Site Key and a DDS Key. My advice is toread and digest these documents to ensure that you give thecorrect information on the form, or it will delay the process.
The receiver I was originally going to use was the Technisat
Skystar USB 2.0, but on initial tests the signal strength wasvery poor, so I switched immediately to the DVB World
receiver. What a difference that made.
The DDS Receiver software you require will be sent to you via
email, with instructions on installation. Once DDS Receiver
has been installed on your PC there comes an important partof the process where you have to give the correct MAC Codefor your receiver. The best way to do that in Windows XP is
to click <Start - Run> and enter 'CMD' followed by the 'Enter'key to bring up the Command Box. When you see theflashing icon, type 'ipconfig/all', followed by 'Enter'. All the
hardware attached to your PC will be listed, so look down
until you find your receiver's name. What you are looking foris the Physical Address of the receiver, and mine was'00-18-BD-00-00-00', so this was the MAC Code that I sent
to the DDS Team.
There is also another way to find your MAC Code. If you
have DVB World installed, open up the program and go to
the IP Config tab. Open that and, at the lower left handcorner of that box you will see 'MAC Address Information'.
This is the code required by the DDS Team. If you are
unsure use both methods to get the right code.
A further email will be received containing the DDS Key thathas to be entered into the DDS Receiver software to enable it
to start. To do this, copy the file from the email and paste it
into the DDS Receiver file. Once that is done the receiver will
start.
So, having installed the DDS Receiver software andconnected your receiver hardware (DVB World model in mycase), the next task is to locate the satellite, a very criticalpart of the operation.
I am using a 1m satellite dish, ground mounted on astand. I am located on the south coast of England at 70
metres above sea level, with a clear takeoff to all horizons
except north, providing a clear field of vision towards theEutelsat satellite at 10°E. You might think this sounds
easy, but not so! With everything that is up there, its liketrying to find a needle in a haystack. What you must do is
to first locate Eurobird 9 with EUMETCast which, with a
1m dish gives a thumping great signal: mine was 100%.
Having located Eurobird 9 and tested the signal, it isnecessary to reprogramme the DVB World receiver for
Eutelsat W1. Page 7 of the Envisat DDS Receiver manuallists the parameters to set in order to receive Envisat DDS
Data. They are:  }}   # & | }}
 &  >& 
 |      ¡  }{ #
It is particularly important to check that the polarization
setting is correct. To do this, go into the DVB World
settings and open the 'IP Config box'. This displays twopanels: on the left 'Satellite Configuration' and on theright (below the Stop/Start IP box) it tells you which
settings you have on Eutelsat W1. Make sure you havethe correct polarization, i.e. horizontal. If it is vertical,
change it or the system will not work.
You may be thinking I have chosen the wrong satellite:
shouldn't it be Eutelsat W2A?. This depends on yourreceiver software. In my case the software listed the W2Asatellite at 16°E and the 10°E satellite as W1. Needing asatellite at 10°E, I went for Eutelsat W1. Moreover, it was
the DDS Receiver Manual that I had taken my settingsfrom so it had to be right. And it was!
This next part is not easy and has to be done carefully.
Having located Eurobird 9, I immediately marked a lineon the concrete slab in line with the LNB bracket toensure I could always return to that position and startagain. Now determine 10°E using a compass. As
described by Arne van Belle’s in GEOQ 29, the optimal
distance between 9°E and 10°E LNBs would be 17mm fora 1m standard offset dish.
I measured 17mm out from my original line, directly
below the LNB, and drew a line from that point back to
the centre line of the dish's vertical pole. When I checkedwith my compass it was one degree. When I now moved
the dish (using the LNB bracket) to line up with my new
17mm line, my satellite meter read full scale. I thenopened up my DVB World program to 'Sat Config' andclicked on 'Lock TP'. This gave really good Signal Strength
meter (72%) and Quality (60%) readings. I was now set up
and minor adjustments made very little difference to thereadings so I locked everything at that.

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GEO Quarterly No 30

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June 2011

If you have any problem locating the Eutelsat satellite you
can do a scan which will bring in all the stations on thatsatellite and also confirm you are on the correct Eutelsat
W1. Tune to a station called ANB Arabic News Broadcast,which has a much stronger signal (89% with me).
I have also gained a bonus from this as I can now receive
Eurobird 9 with the dish in that position, at 95% Strengthand 60% quality—one dish two satellites. And as I alreadyhad two cable feeds to that system, I am purchasing atwin output LNB to run both systems together from thesame dish, using a second DVB World for EUMETCast.
I had to enter my PIDs, 230 and 231(decimal). Pressing
the Scan PID button should enable you to find them: if
not, enter them manually.
There is one other very important point, the Envisat DDS
Receiver comes set with an IP Address of 10.2.0.1, so you
have to go into 'Network Places' on your PC, right click on<Properties-Locate DVB Adaptor>, right click 'Go toproperties', then highlight 'Internet Protocol (TCP/IP)' thenclick 'Properties'. Highlight 'Use Following IP'. Enter the IP
10.2.0.1 and make sure the subnet mask is set at255.255.255.0. Click 'OK' and come out of that system.
Just a note you do not have to use the above IP Address.
If you decide on a different one, the file to edit is: ddsrecv-cfg.ini. in the [transmission] section and use Notepadwhen editing the file.
A look on David Taylor’s excellent website will also give
you more information on editing and software changes.
It’s a good idea to stop all systems and restart again. ThisI did and all started working immediately. Envisat data
started to come in, success that I did not believe possible.
I felt a great sense of achievement.
My thanks to David Taylor and Arne van Belle, for their
excellent articles on Envisat DDS. The information fromthem was very helpful.

Continued from page 22
http://www.kickstarter.com/projects/dannypier/astdroid-letssend-a-smartphone-into-space

Many images are "unusable" as "scientific" users would
point out, but Sputnik was the start of a small trendthat has given us MSG and ENVISAT/METOP.
Problems would be stabilisation, longevity,cost,weightetc BUT, if successful APT transmissions could
continue with a suitable vehicle?
Perhaps we could really be THE group that does
observe the earth from space with out own payload!
http://www.sstl.co.uk/
http://www.sstl.co.uk/divisions/earth-observation-science/science-missions/strand-nanosatellite

There are "basic" satellites for earth observation in
space already, is it possible to receive them directly?, if
so how?
http://www.sstl.co.uk/Downloads/Datasheets/SSTL_100Feb-09

44

A free app, tested on an iPod touch.
This application is primarily designed to show whensatellites are above the horizon from any given location, andthus when radio signals may be received. It could, however,be used to provide information when certain satellites (suchas the International Space Station, ISS) are visible.
There is a large range of satellites available by default, and
it is easy to chose which should be displayed. The choice isvast, including categories for amateur radio, earth
resources, GPS, geostationary (an enormous list), Iridium,
ISS, science, and weather. A lot of the satellites andspaceprobes are only of interest to those who, like birdwatching twitchers, want the satisfaction of ticking them off
on a list. I can’t see that anyone can otherwise really wantto listen to the XMM-Newton astronomy satellite, forexample.
The only slight inconvenience, as far as weather satellites
are concerned, is that all the NOAA series, for example, and
METOPS-A, are listed under their SARSAT numbers. The
Satellite Selection function does display the more familiar
designations, and by selecting a particular satellite, goingto the tracking display (of which more in a moment) andthen selecting ‘Details’ one can enter the NOAA or METOPS-A
designation in a ‘Comments’ field, and this will then be
shown on the actual tracking display.
Various options are available under ‘Preferences’, including
setting the default location, the minimum elevation above
the horizon, the number of days for which future passes areshown, and the number of days before you are prompted
for Kepler updates (which happens when you open theapplication).

Happy weather watch from Portland.

David PainterStorm Dunlop

Once set for location, and for a subset of satellites, pressing‘Satellites’ shows the selected satellites, with their next AOS
or LOS with its predicted time in UTC, and the time (inhours and minutes) until the event. Selecting a specificsatellite then shows a black-and-white ‘radar-type’ plot
centred on the zenith, circles indicating elevations of 30°
and 60°, the predicted path, and times along the path at2- or 3-minute intervals. If the satellite in question is above
the horizon, it will be shown as a solid black symbol, theposition of which seems to be revised every minute. Other
data shown are: range, azimuth, elevation (all updated
every second), satellite altitude (in km) and velocity (inkm/s). Pressing ‘Details’ from the tracking screen shows alist of future passes, with AOS, LOS, and maximum
elevation. Selecting one of these will show a tracking plot,
and here the only real fault that I find is that it does notshow the date, only the time of the pass.
There is a comprehensive set of information and instructions
which are easy to follow and implement.
Satellite Tracker Plus (£1.19 from the App Store), which I
have not tried, apparently adds graphical displays of asatellite’s ground track and footprint.

www.geo-web.org.uk

© EUMETSATImage of the South Pole taken on the 31st October 2010 as Antarctica’s summer approached.
The Ross Ice shelf and Murdoch Sound predominate

Continued from Computer Corner page 41