Bookmark this page:
If you were Registered and logged in, you could reply and use other advanced thread options
Today Russia, Tomorrow the World!
System Design & Test Newsletter, June 2009
http://sidt.gpsworld.com/gpssidt/article/articleDetail.jsp?id=3D605951=
Jun 24, 2009
By: Alan Cameron
We have something for everyone except Compass devotees in this issue of t=
he newsletter.=20
GLONASS looks stronger by the minute, having reached full operational cap=
ability over=20
Russian territory. Correlatively, so also grows stronger users=E2=80=99 c=
apability worldwide to=20
fill current or impending GPS gaps with GLONASS satellites.
The European Commission appears to have Galileo matters firmly in hand, a=
warding satellite=20
contracts and advancing in due and deliberate course, although not all co=
ntractors sound=20
happy about it. And GPS operators solved one problem, moved up one launch=
, and have=20
probably held back another.
GLONASS. As a result of recent launches, the Russian Space Agency website=
lists 18=20
operational GLONASS satellites as of June 22. Under system definition, GL=
ONASS requires 18=20
satellites for continuous navigation services covering the entire territo=
ry of the Russian=20
Federation, and 24 satellites to provide services worldwide.
Two Proton-M launch vehicles are expected to lift off this year, one in S=
eptember and one=20
in December, to put between them six more GLONASS-M satellites into orbit=
=2E Unless some of=20
the current 18 go out of service =E2=80=94 which has been known to happen=
periodically with the=20
relatively short-lived GLONASS vehicles =E2=80=94 that would bring the Ru=
ssian constellation to=20
the requisite 24 for worldwide FOC.
In March, Sergey Revnivykh, deputy head of the Global Navigation Satellit=
e System=E2=80=99s=20
Mission Control Center in Moscow, told the Munich Satellite Navigation Su=
mmit audience=20
that GLONASS aims for =E2=80=9Cavailability in city jungles and mountain =
canyons=E2=80=9D with this more=20
numerous constellation. Seventeen of the satellites transmit two civil si=
gnals, in two=20
bands, L1 and L2. Revnivykh claimed 5-meter =E2=80=9Cideal receiver posit=
ioning accuracy=E2=80=9D=20
currently, compared with 2-meter accuracy for GPS.
A test flight of the new GLONASS-K satellite will take place in 2010, he =
predicted,=20
putting forth a new signal on L3. This will be a CDMA (code-division mult=
iple access)=20
signal similar to GPS and Galileo signals, rather than the FDMA format us=
ed by the=20
Russians to date. It heralds a new set of GLONASS signals to be implement=
ed for the=20
future, interoperable with other GNSS.
Revnivykh has in his sights a GLONASS performance compared with GPS and G=
alileo by 2011.
GPS World contributors have recently offered two studies showing how user=
s with=20
GPS-GLONASS equipment can improve their accuracy and availability. See Ge=
rard Lachapelle=E2=80=99s=20
and Richard Ong=E2=80=99s study and Richard Langley=E2=80=99s analysis.
In other developments, Russian announced it will launch two multipurpose =
relay satellites=20
in 2010-2011, which will carry payloads for providing GLONASS correction =
data. "They will=20
provide the opportunity to receive high-precision GLONASS signals in all =
territory of=20
Russia," stated N. Testoyedov, DG of Reshetnev Informational Satellite Sy=
stem company.
Loutch-5A will be launched in December 2010 and Loutch-5B in December 201=
1.
Previous Loutch (also called Luch) geostationary satellites have been use=
d for relaying=20
communications between the International Space Station and other space ve=
hicles and the=20
ground. They are analogous to the U.S. Tracking and Data Relay Satellites=
=2E
Thales Alenia Space, who are manufacturing some of components for the sat=
ellites, have=20
indicated that the satellites will be positioned at 16-degrees west and 9=
5-degrees east:
Galileo. On June 15 at the Paris Air Show, the European Space Agency (ESA=
) signed two=20
contracts for the procurement of so-called long-lead items required for t=
he construction=20
of the Galileo satellite constellation. Ren=C3=A9 Oosterlinck, ESA Direct=
or of the Galileo=20
Programme and Navigation-related Activities, under the vigilance of Paul =
Verhoef,=20
Programme Manager of the European Union Satellite Navigation Programme at=
the European=20
Commission, signed two separate contracts with Astrium GmbH and OHB Syste=
ms, the latter a=20
German company and the former a German-French partnership with significan=
t British=20
involvement.
Both Astrium (=E2=82=AC7 million) and OHB (=E2=82=AC10 million) contracts=
relate to parts for equipment of=20
the satellite platforms and navigation payloads. Award of the satellite c=
ontracts=20
themselves is planned to take place by the end of 2009.
On the following day, ESA and Arianespace signed a contract for the launc=
h of the first=20
four operational Galileo satellites on two Soyuz launch vehicles from Eur=
ope=E2=80=99s Spaceport=20
in French Guiana. The four IOV satellites will be placed in a circular or=
bit at an=20
altitude of 23,600 kilometers by the end of 2010.
Conversations at the Air Show seemed to indicate that ESA and the Europea=
n Commission may=20
divide the satellite construction contract into two stages to permit a la=
ter modification=20
of the design, and that they may also divide the first satellite contract=
between the two=20
bidders, Astrium and OHB. Oosterlinck characterized this possible contrac=
t split as an=20
insurance policy to reduce the possibility of further development delays,=
and as a boon to=20
design flexibility.
The CEO chief executive of Astrium Satellites publicly and sharply critic=
ized the airing=20
of this option, saying that it would increase overall program cost. The C=
EO of OHB seemed=20
more sanguine about the matter, and lauded ESA=E2=80=99s move as likely t=
o maintain a competitive=20
environment.
GPS. It appears that the difficulties with the L1 signals from the recent=
ly launched Block=20
IIR-20/M7 satellite, SVN49/PRN01, which are preventing it from being set =
healthy, may not=20
delay the planned launch of the final satellite in the Block IIR-M group,=
SVN50. The=20
previously announced launch date of 21 August for this satellite has been=
moved up to 17=20
August. SVN50, jocularly known as "wet-sat," was refurbished and moderniz=
ed after being=20
damaged by a leak in a room at Cape Canaveral during a severe storm back =
in May 1999.
Since we currently have 30 operating GPS satellites in orbit with another=
three residual=20
satellites that can be reactivated in about 10 days to two weeks, there i=
s no need to rush=20
SVN-49 into service, so a little more time testing and adjusting the corr=
ection parameters=20
is the prudent way to go. Currently the Wing expects the 2SOPS at Schriev=
er to set the=20
satellite to healthy status sometime in the September-October 2009 timefr=
ame. This is=20
around the same time that IIRM-21 should be set healthy as well, if all g=
oes according to=20
plan.
GPS contributing editor Don Jewell filed a report on SVN-49=E2=80=99s tro=
ubles and how the Air=20
Force plans to remedy the situation.
For those of you paying attention to launch schedules, this should have b=
een about the=20
same time that the first IIF satellite would have been launched, but it l=
ooks like that=20
will now not take place until the January-February timeframe in 2010.
Meanwhile the fallout continues from the GAO report stating the likelihoo=
d of a drop in=20
satellite numbers for the GPS constellation. After reading the Langley an=
alysis (mentioned=20
earlier in the GLONASS section of this article) in the CANSPACE list serv=
ice, one=20
subscriber wrote in to say, "We are using GPS for forestry related purpos=
es in British=20
Columbia. The results you are modeling here are similar to what we curren=
tly experience=20
with 30 satellites, given the mountainous terrain and forest cover (we mu=
st have 3D=20
positioning). Depending on location, there are already windows of time wh=
en work is not=20
possible. It would stand to reason that we would experience further degra=
dation from what=20
you predict here and therefore even more down time. This could be a serio=
us problem for=20
our industry."
Another reader responded to the story, "While Richard Langley's work give=
s a good reality=20
check on the more dire warnings, there will be a lot of people expecting =
their car=20
navigation systems to work 24/7 even in 20- degree elevation mask conditi=
ons. Richard's=20
findings at 20 degrees are cause for genuine concern (80 to 125 minutes o=
f total outage=20
per day at 23 to 21 satellites and significant position quality degradati=
on)."
