**101^st^ Meeting of the Satellite Telemetry Interagency Working Group
(STIWG)**

Virginia Beach, Virginia

Wednesday, March 24, 2004

**Minutes**

**[Call to Order and Welcome]{.underline}**

The STIWG meeting was called to order at 9:00 a.m. by Ernest Dryer of
the U.S.G.S., who is the Chairperson for 2004. It was announced that the
morning would by given to technical presentations and would be open to
non-STIWG members. The normal STIWG meeting was to begin after lunch.

**[Welcome from the NOAA National Ocean Service]{.underline}**

The host of the STIWG meeting, the NOAA national Ocean Service, welcomed
the STIWG members.

**Presentations of DCS Project Studies Sponsored by NOAA/NESDIS**

**[GOES DCS Backup Study]{.underline}**

Mark Bailey and Jean Pohl of AC Technologies presented the results of
their work on a viable DCS backup system concept that would ensure
continuation of data processing if Wallops should ever fail. The Power
Point presentation is included as an attachment to these minutes. Two
backup scenarios were mentioned: (1) a centralized one which would be
conceptually like Wallops only in reduced scope, and (2) a distributed
backup design that would utilize multiple users' data DRGS data sources
rather than directly acquiring the data from GOES. Data distribution
would otherwise be the same for both concepts. AC Tech. emphasized the
distributed system during the STIWG discussion. Secure Internet data
feeds would be emphasized and the Domsat link would be continuously
monitored for failures. There would also be continuous monitoring of the
LRIT link (which could be relaying DCS message data). Phil Whaley said
that the LRIT link is already backed up at the Wallops image backup site
located at the Goddard Spaceflight Facility in Greenbelt, Maryland. Test
messages will be used to verify the DCS backup link prior to data
distribution. There would be a rapid deployment of Wallops CDA staff to
the backup facility if there was a primary system failure.

A question was asked regarding the planned backup system database and
how frequently the system updates would occur, for instance to the PDTs.
It was stated that the database would never be more than 24 hours behind
the primary system. A more serious concern would be getting changes that
have been made to the database while the primary system was down back to
Wallops. Data base operations at the backup site will be scaled back
versions of that done on the primary system.

The selected site for the facility would be the new NSOF (NOAA Satellite
Operations Facility) building that is under construction in Suitland,
MD. There were opinions from users indicating that the chosen site was
too near the existing Wallops location. The guidelines that NOAA gave to
AC Tech. only specified at least 50 miles separation. It was also
pointed out that if Suitland was down, there would be no spacecraft
control anyway, and therefore no data to be processed. However, it was
stated that at least, Fairbanks could control the GOES West. AC Tech.
mentioned that the report represents the findings of a study and is not
a final design.

AC Tech. is recommending that quarterly fail-over drills be part of
backup system standard operations.

A final report from AC Tech. is due in April, 2004, and will be posted
on the DCS Internet site. AC Tech estimated a ROM backup system cost of
\$2.5 million.

**[LRIT Development Status]{.underline}**

Jeff Manning of Science and Technology Corp. presented the status of the
transition from the analog WEFAX to the digital LRIT service. LRIT has
an allocated maximum bandwidth of 256 Kb, and it currently using 128 Kb.
Plans were to begin the service with GOES N, but transition has begun
with the current GOES East satellite and will begin on the GOES West
sometime this spring (2004). Current LRIT products include charts,
imagery, and EMWIN. Beginning last October, the alternating
transmissions of WEFAX and LRIT were begun with 29 minutes of LRIT
alternating with 31 minutes of WEFAX. It is planned to continue this
schedule through October 2004. DCS data are also being inserted into the
data stream. There were questions from users about the latency and
priority level for DCS message data. He reported that no latency tests
had been performed, and that the priority level for DCS data has not yet
been determined. He said that a 1.2 meter dish was working fine there at
Virginia Beach and without accurate alignment. Volunteers are needed for
testing the DCS data stream for determining properties such as latency.

Jeff invited users to come and witness a demonstration of the system
that he had installed there in the hotel.

Interested users can find more information at
<http://noaasis.noaa.gov/LRIT> and provide comments to <lrit@noaa.gov>.
The URL for additional operational information was listed as
<http://www.osdpd.noaa.gov/cob/cob.html>.

# [CDMA Study]{.underline} 

Duane Prebel, representing Morecom International presented the status of
the investigation to determine the applicability of CDMA technology to
the DCS environment. The scope of the study covers the concept of a
coexisting CDMA system overlaying the existing 400 KHz DCS band.
Theoretical studies are completed and Morecom is working with Microcom
Design on a CDMA DCP design that will soon be ready for testing using
the Microcom DRGS. The next phase of testing is planned to be using the
Wallops CDA facility for a test which will more closely resemble true
DCS operations. The DCS RF links being studied for possible CDMA
functions consist of both the DCPI and the DCPR. Duane said that the
DCPI would only be modeled and not physically tested.

An absolute requirement of the CDMA study is that there must not be any
interference with the existing FDMA/TDMA system. Duane referenced one
study that indicated maximum RF efficiency could be achieved by using a
mixed CDMA and TDMA/FDMA system. Data rates for the CDMA system will
probably be about 100 to 200 bps. System management should be much
different from that which is currently in use. A guideline being used is
to have the data ingest phase at the Wallops CDA look just like the
current data.

Richard Schwarz of Microcom Design next presented engineering details of
the software/hardware approach that is being used on the CDMA study. He
said that they are nearing Phase 2 of the study which is prototype
implementation. They intend to utilize the latest technology chips and
subsystems that are available. Code will be primarily portable C++. Low
power chips will be utilized, some as low as 1 volt to minimize power
drain. The design will also utilize existing Microcom boards/subsystems
that can be adapted to the system. The actual software radio will be
able to implement TDMA and/or CDMA signals. The initial goal is for 50
CDMA simultaneous users at a 37 dBm power (EIRP) with a noise floor 29
dB below the 1200 bps transmitters operating at a 50 dBm level. There
will be tests to determine the CDMA limits against 1200 bps
transmissions (which are the most prone to interference).

Kay proposed use of CDMA for the random channels which would thus free
30 channels that currently have random transmission assignments. The
group adjourned for lunch at this point.

**[Afternoon Session Call to Order and Welcome]{.underline}**

The afternoon session of the STIWG was called to order by Ernest Dryer,
the Chairperson for 2004. The STIWG officers for 2004 were announced:
Ernest Dryer is the Chairperson and Alan Pilak of the NOAA/ERG is
secretary. Since Alan Pilak 2004 was absent, Jim Wydick, who was one of
the NESDIS support personnel, was doing the minutes for this meeting.
Next were introductions of supporting personnel which included Letecia
Reeves who is now officially Carol Green's replacement in NESDIS, and
Peter Woolner of Mitretek Systems who has been doing advanced DCS
telecommunications studies in support of the DCS.

**[Afternoon Session Welcome from the NOAA National Ocean
Service]{.underline}**

Mark Bushnell of the National Ocean Service, the host of the meetings,
provided a presentation explaining the various aspects of the NOS's work
that is supported by the DCS. It was interesting to learn of how the
East Coast harbors are becoming more shallow and the link between DCS
monitoring to predict draft depth clearance for ships.

Mark showed how sweeping microwave sensors are being used to monitor
water level in addition to the more traditional water level gauges.
Water level is important for determining bridge clearance. Mark
explained how six minute observations are needed for current observation
allowing timely predictions.

**[Review of Agenda]{.underline}**

The agenda was reviewed and approved. Ernest said that most of the
topics should be short and that additional topics would include a report
on DAPS II progress and a discussion of the mornings 3 technical
presentations.

**[Approval of Previous Meeting Minutes]{.underline}**

The minutes from the last meeting were reviewed and approved. They are
available at the following web site:
<http://water.usgs.gov/datarelay/stiwg/meetings/stiwg_meetings.html>

[**Action Item Review**]{.underline}

Action items from the last meeting were reviewed and discussed:

**Action**: DOMSAT contract extension. **Status:** Complete.

**Action:** DOMSAT Funding Plan. **Status**: Incomplete.

This action generated substantial discussion regarding how the costs
would be born by various agencies. The National Ocean Service will be
added to the existing list as a major user and DOMSAT funding source. It
is estimated now that each of the nine funding agencies will be asked to
contribute from \$7,000 to \$9,000.

**New Action: Ernest Dryer will determine the exact DOMSAT payment for
each agency. Also Ernest will authorize the next payment.**

**Action:** Letter to NTIA. **Status:** Incomplete

There was a continuation of last meeting's discussion regarding
continued RF interference within the DCS band. There seems to be no easy
solution for locating and eliminating bogus RF signals. But it was felt
that the NTIA is the agency charged with handling problems like this, so
a new action was generated.

> **New Action: Ernest Dryer will work with the Wallops CDA to draft a
> letter**

**with supporting details to the NTIA which will point out the frequent
abuse of the GOES DCS RF band and specify the continuing interference in
DCS channels 65 and 66. The relationship of the DCS to homeland security
will also be emphasized.**

**[Treasurer's Report]{.underline}**

Doc Carver of the OFCM who is the treasurer was not present. However, it
was reported that the DOMSAT funding had been spent on the contract
renewal. Members expressed the need for regular STIWG treasury reports.
It was hoped to get Doc Carver to come to the meetings. No change to the
treasury was known other than about \$27,000 that was paid for DOMSAT
leaving about \$60,000 to pay the \$52,944 which will be due for the
next DOMSAT payment.

**New Action: Ernest Dryer is to contact Doc Carver to determine what
level of participation the STIWG can expect.**

**[STIWG Terms of Reference]{.underline}**

Discussion of the Terms of Reference centered on the matter of absent
members voting by email. There were pros and cons expressed by the
attendees. It was determined that the new wording that would allow email
voting had not been added to the document. It was taken as an action by
Ernest Dryer to amend the terminology and complete the action that was
generated at the previous meeting.

**New Action: Ernest Dryer to modify the Terms of Reference to allow
email voting at special meetings for viewing on the Internet and forward
the Terms of Reference to the parent organizations for review and
approval.**

The Terms of Reference may be viewed at the following URL:

<http://water.usgs.gov/datarelay/StiwgTor-new.html>

**[HDR Demod Status]{.underline}**

Kay presented the current status of the DCS HDR demodulators. She said
that there had been discussions regarding an emergency procurement for
sixty or more high data rate demods within ninety days from Microcom
Design. Al Mcmath added that these demods will use a new interface to
communicate with the current Data General DAPS. Kay remarked that she is
still limited by the number of channels that are available for
assignments. Kay reported that the random channels are preventing her
from making more assignments. She also reported that she is trying to
get permission to use the international channel allocation for random
channel assignments, but approval is required from the CGMS whose next
meeting is in May of this year in Russia.

**[HDR User Transition Subcommittee Report]{.underline}**

All requested changes have been made to the draft and the GOES High Data
Rate Transition Plan is ready for member voting. Kolleen Shelly
distributed copies of the document for review. There were no objections
to the plan so Ernest Dryer declared the plan as accepted.

Kay Metcalf requested users to transition from the higher channels first
and to start as soon as possible.

**[Transmitter Locator Status]{.underline}**

The letter complaining about the DCS interference was mentioned again,
and it was emphasized that it needed to be written. There was also some
discussion about the former TLS study and demonstration. Kay Metcalf
explained that there were no NESDIS funds that would allow the current
development of a TLS system. The timely completion of a letter to the
NTIA is covered in an above action item for Ernest Dryer.

# [DAPS II STATUS]{.underline} 

Kay reported on the question of whether the contractor (ISI) will
upgrade DAPS II to the latest Oracle version or not, and who will pay
for it. The DAPS II PAT (acceptance test) had been delayed from December
2003 to allow the Oracle upgrade. It was also mentioned that the
contractor's view of the acceptance test was that no users would be
allowed on the system during the test period. STIWG members said that
they needed to see some DAPS II documentation and Kay Metcalf replied
that the documentation that has been received from ISI was not
acceptable and she did not want to distribute it. To answer a question,
she said that the backup system was scheduled to follow DAPS II and not
precede it. She also answered an Oracle question saying the current
Oracle version on the system is 9Ias release 1. She estimated a DAPS II
transition preparation by sometime in FY 2005.

# [Backup System Status]{.underline} 

# The location chosen for the DCS Backup System (Suitland, MD) concerns the STIWG members. Ernest Dryer explained that if command and control is lost at Suitland due to a Suitland catastrophe, it does not matter where the backup system is since there will be no satellite services. It was pointed out that the critical DCS functions (command and control, data reception, and pilot reference signal) needed to be separated. Users voiced a special need for a pilot reference signal backup in case of a failure at Wallops. In response to a question about electrical power backup at Wallops, Al Mcmath reported that Wallops has backup diesel power generation that will go for an extended time. Additionally, the buildings at Wallops have also been reinforced. It was emphasized that NESDIS had followed a NOAA directive which states that recovery sites must be at least 50 miles from the primary site which is being backed-up. It was also established that the backup system will be a hot backup. The proximity to the Wallops CDA staff was also an important factor in choosing the Suitland site.

> **New Action: The STIWG will generate a letter to the OFCM and/or
> Hydrology** **Working Group detailing their GOES DCS Backup System
> concerns.**

# [LRIT Status]{.underline} 

The STIWG is still looking at the LRIT stream as a backup to the DOMSAT.
However DCS is not considered primary within the LRIT data stream at
this time. Data latency, complexity, and capacity are all concerns to
the STIWG. The STIWG will continue to monitor the development of the
LRIT service.

**[CDMA]{.underline}**

Ernest Dryer expressed the concern about safeguards for the DCS system
during the CDMA development. Peter Woolner expressed doubts about the
level of interference that can be expected within the DCS by CDMA
transmissions. Random channels with low power CDMA DCPs were advocated.
The STIWG will continue to watch this issue as it develops.

**[Manufacturers' Meetings Review]{.underline}**

Ernest Dryer reviewed the previous two days' manufacturers meetings for
the group. The meetings had been held to discuss proposed changes to the
DCS DCP certification standards in the GOES-R era which should begin in
2012. It is being proposed that the channel spacing would be halved from
1.5 KHz to 0.75 KHz for the 300 bps service. That change would result in
a doubling of the 300 bps channel capacity. A similar band reduction
would be applied to the 1200 bps service which now utilizes two
channels, or 3.0 KHz band width.

The next topic reported on was the DCPI service. It was revealed that if
the DCS community does not start using the interrogate DCS band, there
is a probability that it will be not be included in the GOES R
generation of spacecraft. Ernest Dryer asked the STIWG members if there
was justification to keep the DCPI. There were suggestions for using the
DCPI to potentially control DCP power and control, for instance to stop
the transmission of an errant DCP. It could also be used for accurate
timing functions. Ernest requested user input for support of the DCPI
service. It was pointed out that the DCPI frequencies can only be used
in the interrogate direction and not the reverse. There are currently 3
DCPI channels (47 KHz) available. There was enough spontaneous support
for the service that Peter Woolner said that he would report back to
NESDIS that the DCPI service should be continued on GOES R.

**New Action: DCS members are requested to determine future uses of the
DCPI that would justify the continued existence of the service. Peter
will tell Dave Maginnis, who represents NESDIS in RF matters, that he
attended the meeting and that the STIWG supports the continuation of the
DCPI. Member input on this action is to sent to: <ptippett@usgs.gov>**

**Next meeting:** The next meeting is planned to be in conjunction with
another manufacturers conference dealing with the certification
standards during the first week of August in Seattle, Washington.