EMWIN Transition Plan

December 17, 2003 Version

EMWIN Transition Plan

**Introduction**

Changes to the NOAA's GOES N-series satellite frequency assignments and
transponder characteristics will require corresponding upgrades to the
National Weather Service (NWS) Emergency Managers Weather Information
Network (EMWIN) broadcast from the GOES satellites. The National
Environmental Satellite, Data, and Information Service (NESDIS),
responsible for satellite and ground system design and implementation,
and the NWS are working together to plan for the implementation and
transition of the new EMWIN services within the future GOES N-series --
the GOES-N, -O, and -P. This EMWIN implementation and transition plan
identifies the related issues and actions required to achieve a
successful transition. The GOES related broadcast changes consist of a:

-   Change in the broadcast frequency ... from 1690.725 MHz to 1692.700
    MHz

-   Reduction in the power level of the broadcast ... from 51 dBmi to 43
    dBmi to meet ITU regulations.

-   Change of signal modulation ... from Frequency Shift (FSK) to Binary
    Phase Shift Key (BPSK), and

-   Introduction of Forward Error Correction Coding (FEC) ... using a
    Reed-Solomon Convolutional Code

-   Replacement of WEFAX ... by LRIT.

The EMWIN data rate will remain as it is currently at 9.6 Kbps. The
EMWIN data content will also remain the same.

A transition from current EMWIN operations (EMWIN-I) to the GOES
N-series era EMWIN operations (EMWIN-N) is required as a result of these
changes. This plan documents those required activities to develop, test,
and make available a new EMWIN receiver system to the vendor community
for the transition.

## Background

Number range CHAPTER

The EMWIN mission is the timely dissemination of NWS warnings, watches,
forecasts, and other products to the nation's emergency management
community, and many other public and private organizations. A goal of
EMWIN is low user cost access to a live stream of weather data and other
critical emergency information. One means of providing this access is
dissemination through the GOES satellites, and direct reception with a
low cost receiving system. Number range CHAPTERIn some communities, the
EMWIN signal received from GOES is then rebroadcast by the NWS and other
public and private agencies as an audio signal on a dedicated VHF or UHF
radio frequency. This rebroadcast signal can be received, by anyone
within the 40-50 mile broadcast area, using an inexpensive radio
receiver, a demodulator, and a personal computer.

When the GOES N-series becomes operational it will render current EMWIN
receiver systems unable to receive and process the EMWIN datastream and
thus will require changes to existing EMWIN receiver systems in order
for users to continue to receive and demodulate the EMWIN-N broadcast.
The new receiver systems are needed to accommodate the changes in
frequency and modulation technique and the addition of Forward Error
Correction. NOAA plans to minimize the impact of these changes on both
the receiver system vendor community and the user community by building
in a transition period in which new receiver systems are designed,
built, marketed, and become operational. During this period the existing
EMWIN-I broadcasts will continue and early coordination with the user
community conducted.

The first launch of a GOES N-series satellite is currently planned for
December 2004. A six-month checkout period is planned for January
through June 2005. If the then-current constellation has experienced no
problems (likely GOES-10 and --12), following the checkout period, the
satellite will be placed in a storage orbit until it is needed. It is
now planned to be in storage until as late as July 2008, when it will
replace the operational GOES East at its end-of-life. To summarize, the
earliest operational date of GOES-N is July 2005, while the latest date
of first GOES-N operation is July 2008; the most probable operational
date is somewhere between these two dates.

**Transition Concept**

A phased transition is planned from EMWIN-I to EMWIN-N, barring
premature satellite failures:

1.  The EMWIN transition activities began with the award of a prototype
    receiver system development contract to demonstrate a technological
    solution to meet the changed EMWIN broadcast characteristics,

2.  The second phase will be the release of the prototype and
    development information to prospective vendors; their production of
    systems; purchases by users and users installing the new systems to
    receive the existing EMWIN-I broadcasts from the GOES satellites,

3.  The third phase, which will overlap the Second Phase, will be the
    periodic broadcast of a duplicate EMWIN GOES N-type datastream from
    a normally stored satellite

4.  The fourth phase will be the broadcast of the EMWIN-N datastream
    from the GOES-N satellite, currently planned as GOES East

5.  The Fifth Phase will be the broadcast of the EMWIN-N datastream
    through the GOES West satellite.

NESDIS stores spare satellites in geosynchronous orbit over the US until
they are needed to replace operational satellites that have failed. In
the stored configuration most of the full time communications links and
all of the instrument functions are not available due to the physical
orientation of the satellite. NESDIS removes such satellites from their
stored configuration annually around the summer or winter solstice for
the purpose of verifying the health of the satellites and their
instruments, and to realign their stored configuration.

NESDIS's Office of Satellite Operations (OSO) schedules a nominal 10-15
day period each year in June for the purpose of verifying the health of
the stored satellites. During these periods, the EMWIN-N datastream can
be broadcast through the satellite. OSO testing activities do not affect
or interfere with the EMWIN signal. These periods will provide users and
vendors the opportunity to test their systems in the new operational
environment.

The intention is to minimize user impact by retaining the current
frequency and modulation for all [operational]{.underline} broadcasts
from the GOES I/M satellites. [Test]{.underline} broadcasts from the I/M
satellites will retain the current frequency but the new BPSK
modulation. All broadcasts (test and operational) from the GOES N/P
satellites will use the new frequency and new modulation. When GOES N
first becomes operational, one satellite from the I/M series and one
satellite from the N/P series will be the operational CONUS
constellation. During that period, EMWIN will be broadcast at two
different frequencies and modulations.

The Fourth Phase will be the broadcast of the EMWIN-N datastream from
the GOES-N satellite, currently planned as GOES East. The Fifth, and
final, Phase will be the broadcast of the EMWIN-N datastream through the
GOES West satellite.

Initially the broadcast frequency remains the same so there should be no
change to the receiving frequency. Once switched to GOES N-series
spacecraft, the receiver will need to be "tuned" to the new frequency.
If this is not possible due to the characteristics of a specific
manufacturer's receiver, then a new receiver may be necessary. This is
highly dependant on current user hardware specifics and design details
of the receivers of various vendors.

The Transition Concept is enabled by the flexibility of the new EMWIN
receiver system. The new receiver system uses a completely different
approach than the current EMWIN receiver systems. The new EMWIN receiver
system is based on a custom software application residing in a
commercial/off-the-shelf personal computer with an analog/digital sound
card that will replace the custom hardware demodulator module of the
current EMWIN systems. The EMWIN functional schematic is shown in Figure
1 below.

Assuming the user's existing PC has a capable sound card and sufficient
computing resources, the cost implications to the user are minimized. In
the information technology world, relying on capabilities of any
existing systems, which are more than 2-3 years old, has some risk.
Processors need to be Pentium-class machines. Sound card functionality
has changed exponentially in the past 3-5 years, so the assumption
should be to upgrade the hardware. The current minimum PC available on
the commercial market is a 1.0 GHz Pentium processor with 128 MB memory
and a 20 GB hard disk operating Windows NT/2000/XP. This processor will
utilize 20 to 25% of processing to service the custom software. The
analog/digital sound card used in the development was able to
accommodate a sample rate of 96 KHz with an analog bandwidth of more
than 46 KHz. The development system used an M-Audio 2496 Audiophile
series card.

![](media/image1.png){width="5.625in" height="7.5in"}

Figure 1. EMWIN Functional Schematic

We believe the new software required for demodulation of the information
received from the sound card will not add a significant volume to the
existing software. The PC minimum requirements will be much more heavily
dependent on the EMWIN software and storage requirements than on the
changes to the system caused by the change in the demodulation and FEC.

All users will need to make a change to their front-end receive
equipment to accommodate the frequency change between EMWIN-I and
EMWIN-N, with complexity ranging from a receiver crystal change or
re-tuning, to receiver replacement, depending on the flexibility and
adaptability of their current units.

The custom software will be a variation of the software originally
created for use in the NOAA GOES Low-Rate Information Transmission
(LRIT) system. Additional information on LRIT can be found at:

<http://noaasis.noaa.gov/LRIT>

The variation is the addition of software to de-modulate the existing
Frequency Shift Keying (FSK) signal to the existing software supporting
the new EMWIN-N Binary Phase Shift Keying (BPSK) modulation. Switching
between BPSK and FSK will be by keyboard or mouse input. Both the
current LRIT system and the EMWIN-N will use the same Forward Error
Correction technique, R-S Convolutional.

The Transition Concept is based on the expectation that industry, using
NOAA-provided technical information, will produce commercially available
receiver systems in a timely manner for the user community. The ability
of the new receiver system to operate in either the current or the new
environments makes it possible to provide a lengthy transition period
without dedicating the use of an additionalNumber range CHAPTER
satellite to emulate the GOES-N era data stream solely for test and
evaluation purposes. It is expected the new systems will be placed in
service as they are acquired which will provide an extended period of
operational use. The annual broadcast of EMWIN-N datastream from a
normally stored satellite will provide opportunities for users to verify
their systems will continue to perform normally when receiving the
broadcast from the future GOES N-series satellites.

GOES-8 and -9 are now located in the Central Pacific, at 166 East and
155 East respectively, in view of the West coast, Hawaii, and are under
the control of NOAA's Fairbanks (Alaska) Command and Data Acquisition
Station (FCDAS). Their imaging and sounding abilities are greatly
reduced, but their communications capabilities are fully functional.
These satellites can provide opportunities for vendors to test their
systems at any time of the year with a live EMWIN (-I or --N, but not
both simultaneously) datastream upon a request to the NESDIS Office of
Satellite Operations.

If requested, and if: 1) the basic attitude control functions of the
satellites continue to operate; 2) the communication functions of the
satellites continue to operate; and 3) no other higher priorities arise,
then the broadcasts from GOES-8 and 9 can continue until the lack of
fuel to support North-South maneuvers and the inevitable inclination
growth (\>3 degrees) makes them impractical for EMWIN operations ...
sometime in 2006 for GOES-8 and 2007 for GOES-9.

Assuming users install the new systems, they will be able to operate
them in either the "FSK No FEC" mode (current EMWIN-I) or in the "BPSK
with FEC" mode (GOES N EMWIN-N) by changing the configuration of the
software driver. Thus the users can use the new systems to receive the
current EMWIN-I broadcasts, testing that their systems operate
correctly. When the GOES-N broadcast is available, they can reconfigure
the software driver, change the frequency, re-point the antenna, and
receive EMWIN-N from GOES-N, verifying their systems work in the GOES-N
mode as well.

The footprints for the satellite constellation are provided in Appendix
2.

**Transition Activities**

Transition activities include:

-   Receiver system development, test, evaluation and acceptance

-   NWS dissemination of transition plan and information to customers
    and vendors

-   Vendors provide new systems to market

-   User transition to new systems

-   GOES-N operational

The receiver system test and evaluation phase commenced with the
contract award for a prototype receiver system compatible with the
planned frequency, power level, and formats required for EMWIN-N
reception. The vendor will deliver a dual demodulation (FSK and BPSK)
receiver system capable of operating in either current or planned
operational modes for EMWIN. The desired demodulation will be selected
by a simple keystroke or mouse click configuration change. The detailed
EMWIN Transition Schedule is in the Milestone Section below, and a
summary of the Technical Characteristics is found in the Users Manual.

The receiver system development and evaluation activities start with
contract award, with expected tested prototype receiver system available
by November 2003. NESDIS will provide a simulated broadcast of EMWIN-N
data streams using GOES-N power levels, modulation, and format. The
vendor will be responsible for demonstrating the proposed solution
provides a level of service consistent with the current EMWIN-I
broadcast. This activity ends with acceptance of the demonstrated
capability by NESDIS Office of Systems Development (OSD) Ground Systems
Division and NWS Chief Information Officer (CIO).

The NWS will continue to disseminate transition information as provided
by NESDIS and provide customer outreach support to the EMWIN user
community. The NWS will ensure timely EMWIN transition updates,
technical information and current FAQs are posted on the EMWIN home
page:

<http://iwin.nws.noaa.gov/emwin/index.htm>

Information messages will also be made available to the user community
and vendors through the EMWIN operational broadcast. The NWS will also
respond to the user community on all data and transition schedule
issues. NESDIS will continue to provide technical support to the NWS so
the NWS can continue its coordination with receiver system vendors.

User transition activities span both the development of EMWIN-N receiver
systems and the purchase and installation of those receiver systems by
EMWIN users. NWS will continue to notify current and potential users of
the necessity to have new equipment prior to the switchover to GOES-N
operations. The method of notification is at the discretion of NWS and
is expected to include means such as direct communication with current
customers, broadcast messages via the Internet, and through NWS
publications.

The user will install a new system or reconfigure their existing system
by removing the existing demodulator, re-connecting the RF output to the
IF, if the IF is a separate component, and then to the PC sound card
input port, and configuring the new sound card driver software module
(.dll) using the PC keyboard. The user will re-point the receiving
system antenna to GOES-11 and begin to receive the EMWIN datastream: -I
or -N at the EMWIN-I frequency.

The point of contact for the arrangement of test periods using the
Pacific constellation will be in NESDIS OSD. The current Point of
Contact is: Angelo Wade, E/OSD, (301) 457 5210 x122. NESDIS OSD will
accept requests based on an oral, E-mail, or written request. A written
test plan and schedule will be required from the manufacturer, and a
minimum 2-weeks notice. There will be no costs to the manufacturer. All
requests are subject to deferral for spacecraft or National emergencies.

The vendor's design of the new receiver system will involve new
software, at least the AVTEK .dll, and probably new hardware, an IF
converter. The majority of the testing plan should be executed in the
vendor's facilities. The only need for testing using the a satellite
transmission path should be a validation that the end-to-end system
functions properly.

Vendors and customers will have the opportunity to test and validate
their new equipment using current EMWIN broadcasts and, periodically,
validate that their new equipment operates satisfactorily in the EMWIN-N
mode by ingesting the annual transmissions from the normally-stored
satellites either emulating GOES-N broadcasts or actually broadcasting
from the normally-stored GOES-N satellite following its launch and
checkout.

If vendors are able to supply the first new systems in time for the June
2004 test period, the User Transition Phase could last from June 2004 to
as late as July 2008.

**NOAA Responsibilities**

During the EMWIN transition period, the following responsibilities are
planned:

-   NESDIS/OSD

```{=html}
<!-- -->
```
-   Develop this transition plan

-   Award prototype receiver systems demonstration contract

-   Evaluate/certify demonstration system performance

-   Coordinate with NWS on activities and progress

-   Assist NWS on future receiver systems vendor coordination

-   Participate in EMWIN conferences,

-   Establishment of dates for transition and cutover in coordination
    with NWS

```{=html}
<!-- -->
```
-   NWS/CIO Office

```{=html}
<!-- -->
```
-   Notify customers and vendors of the start of transition activities

-   Issue periodic user notification messages

-   Participate in EMWIN conferences

-   Provision of communications access circuit to WCDAS

-   Coordination of dates for transition and cutover.

The Point of Contact for users and vendors is William Johnson,
NWS/OCIO1, (301) 713­­ 0863. NESDIS will designate a Technical Point of
Contact who will assist the NWS by responding to tasking by the NWS when
necessary to answer vendor inquiries that cannot be answered by the NWS.

## Contingencies

There was a single identified risk: Failure to demonstrate the
successful prototype receiver system solution by the end of October
2003. The prototype receiver system was not completed in time to meet
this milestone and is now encroaching on the time required by vendors
and EMWIN customers to implement, test, and place into operation new
equipment. NESDIS has confidence the demonstration receiver system will
meet the requirements because of prior technical coordination with the
contractor and the contractor's past experience with the similar LRIT
systems. NESDIS fully recognizes the impact of the milestone slip and is
working with the NWS to recover from the impact of the slip.

**Milestones**

Milestones for the EMWIN transition originally agreed to by NESDIS and
NWS are:

1\. June 30, 2003 Contract for demonstration version of a User
Workstation

2\. September 30, 2003 Delivery of a demonstration version of a User
Workstation

3\. October 31, 2003 Complete NESDIS test and documentation of User
Workstation with EMWIN-I

4\. November 1, 2003 Final EMWIN-I/N Transition Plan and User Guide
available for distribution

5\. November 30, 2003 Complete NESDIS test and documentation of User
Workstation with EMWIN-N

6\. December 31, 2003 Final EMWIN-N signal and front-end processor
specifications for User Workstation available to vendors

7\. March 31, 2004 Integration and Test of EMWIN-N uplink equipment at

> WCDAS

8\. April-July 2004 Vendors test new workstation (from West Coast or
Hawaii) using GOES-9 or GOES-8

9\. June 20, 2004 Vendors test new workstation using normally stored
GOES-11

10\. Fall-Winter 2004 Deployment of new workstations to Users

11\. July 2005 Transition GOES-East to the EMWIN-N

12\. March 2006 Transition GOES-West to the new EMWIN-O

#### Current Status

The current status of the milestones for the EMWIN transition is as
follows:

1\. June 30, 2003 Contract for demonstration version of a User
Workstation - Completed

2\. September 30, 2003 Delivery of a demonstration version of a User
Workstation. The signal processing software for a User Workstation was
demonstrated in September

3\. October 31, 2003 Complete NESDIS test and documentation of User
Workstation with EMWIN-I. This milestone was not met because the
contractor had not completed the development. A NESDIS test was
performed on November 11. The documentation of a User Workstation using
the EMWIN-I signal will be delivered before December 31.

4\. November 1, 2003 Final EMWIN-I/N Transition Plan and User Guide
available for distribution. This milestone was not met because NWS and
NESDIS were unable to agree on a final Transition Plan before November 1
and the User Guide was not completed. The agencies have agreed on and
signed this version of the Plan. The User Guide, a presentation of the
technical issues that could affect the replacement or upgrade of
existing user receiving systems, will be completed before December 31.

5\. November 30, 2003 Complete NESDIS test and documentation of User
Workstation with EMWIN-N. A NESDIS test was performed on November 11.
The documentation of a User Workstation using the EMWIN-N signal will be
delivered before December 31. The NWS has requested some further testing
for system latency and longer term error performance.

6\. December 31, 2003 Final EMWIN-N signal and front-end processor
specifications for User Workstation available to vendors. The
specifications are expected to be available by December 31.

## Concurrence

\_\_\_\_\_\_\_\_\_\_[S/S]{.underline}\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
\_\_\_\_\_\_\_[S/S]{.underline}\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Richard G. Reynolds Larry Curran

NESDIS NWS

E/OSD W/CIO1

**Appendix 1**

**EMWIN Acronyms**

ASM Attached Synchronization Marker

BER Bit Error Rate

bps bits per second

BPSK Binary Phase Shift Key

CADU Channel Data Access Units

CCSDS Consultative Committee for Space Data Systems

dB decibel

dBmi Decibels milliwatts isotropic, meaning referenced to a zero-gain
antenna

EIRP Effective Isotropic Radiated Power

EMWIN Emergency Manager's Weather Information Network (NOAA/NWS)

EMWIN-I EMWIN as transponded through the GOES-I/M series spacecraft,
with associated frequency and modulation characteristics

EMWIN-N EMWIN as transponded through the GOES N-Series spacecraft, with
associated frequency, modulation, and coding characteristics

FCDAS Fairbanks (Alaska) Command and Data Acquisition Station (NESDIS)

FEC Forward Error-Correcting Code

FSK Frequency Shift Key

G/T gain-to-noise temperature ratio

GOES Geostationary Operational Environmental Satellite (NOAA/NESDIS)

GOES-I/M A series of GOES spacecraft launched between 1994 and 2001, and
operationally designated GOES-8/-12

GOES N-series The next generation GOES spacecraft (GOES-N, -O, and --P),
with the first launch planned in December 2004

ITU International Telecommunications Union

LRIT Low-rate Information Transmission

NESDIS National Environmental Satellite, Data, and Information Service
(NOAA)

NOAA National Oceanic and Atmospheric Administration

NWS National Weather Service (NOAA)

OSD Office of Systems Development (NOAA/NESDIS)

R-S Reed-Solomon

WCDAS Wallops (Virginia) Command and Data Acquisition Station (NESDIS)

WEFAX Weather Facsimile

**Appendix 2**

**Footprint of GOES satellite CONUS constellation**

![](media/image2.png){width="6.0in" height="4.5in"}

Pacific Constellation

![](media/image3.png){width="5.872222222222222in"
height="4.404166666666667in"}

![](media/image4.png){width="5.872222222222222in"
height="4.404166666666667in"}