Re: Demonstration payload on GPS IIR(M)-20

"Mike Jr" <n00spam@xxxxxxxxxxx> wrote in message
news:41b08601-f59f-4097-ac30-c62f2b62bca4@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Does anybody know if the L5 demonstration package will include sending
ranging data?

--Mike Jr

If by "ranging data" you mean a navigable signal fully complying with
IS-GPS-705 including navigation data, I highly doubt it. The Control Segment
software for L5 support is as far as I know not yet in operation. There is
no absolute need to get a fully compliant signal up there until you're ready
to test to reach IOC. Note that with 6 (soon 7) L2C signals up there for as
long as 3 years, that capability is still "caveat emptor."

I don't have the specifics on the demo payload, but if I were LM and ITT, I
would generate the appropriate PRN sequence (including the NH codes) and
those sections of the navigation message that are generated on the fly by
the payload (time of week, FEC). The rest is likely a fairly static dummy
fill. There may be some provision for the CS to "hand generate" and upload
custom navigation data just to prove out connectivity, but unlike the GIOVE
satellites, there is less of the system that needs proving out in this case.
This payload was a ~$6M insurance policy for the Wing in case the IIF birds
continued to have problems. Given the first IIF launch is now not planned
until fall, it was a very good thing that ITT/LM and the Wing were able to
make this happen. Things could have gotten quite dicey (e.g., confrontation
with the Chinese) if we failed to hit our ITU mandate for a signal by
August.

If I happen across some of my MITRE friends soon, I'll try to ping them
regarding how "real" this signal is. There's more focus on validating the L5
signals from the IIF's once they launch, since those payloads will
eventually become part of the real L5 system. L5 IOC is still seven or so
years from now, since you need all the IIF's and nearly all the IIIA's to
get there.

Patience....do you have an L5 receiver, or would you look at this with a
baseband recording? Talking to some of the Spirent people recently, there's
very few people who've purchased L5 simulation capability yet.

Marty


.

Relevant Pages

  • Re: Demonstration payload on GPS IIR(M)-20
    ... If by "ranging data" you mean a navigable signal fully complying with ... IS-GPS-705 including navigation data, I highly doubt it. ... I don't have the specifics on the demo payload, but if I were LM and ITT, I ... signals from the IIF's once they launch, ...
    (sci.geo.satellite-nav)
  • Re: GPS and Digital Photography
    ... can still be made for much weaker signals than this. ... coefficients, almanac coefficients, satellite health data, satellite clock ... error coefficients, atmospheric error coefficients, and so on. ... integration over periods much longer than a navigation data bit interval. ...
    (sci.geo.satellite-nav)
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