[time-nuts] Thunderbolt firmware differences

Magnus Danielson magnus at rubidium.dyndns.org
Mon Jul 13 06:51:55 UTC 2009


Hi Mark,

Mark Sims wrote:
> I wanted to have Heather make a RINEX file that could be submiited to OPUS-GIS to get a more precise antenna location.   The Tbolt does not support carrier phase measurements.  It does output doppler values.  
> 
> The code phase (pseudorange) values that it outputs look to be VERY difficult to translate into normal pseudoranges.  You need to calculate the satellite positions from the almanac, etc to be able to use them.

You should not use the alamanc ephemeris data but rather use the 
ephemeris data transmitted from that satellite. The difference is in the 
precission. The almanac is meant to help receivers find the birds in the 
sky, but each bird transmitt the ephimeris data that should be used for 
navigation.

> OPUS-GIS is still in alpha testing mode.  I don't know what observable you need to have it post process the data.

Code or Carrier Pseudorange, Integrated doppler
Ephimeris
GPS time

Just read GPS ICD 200 and you should understand most of it. You should 
also have one or a pair GPS books, The Kaplan book is good and classic, 
and the Enge book is more torough, but maybe a bit less practical 
oriented than the Kaplan book. The Kaplan book alongside with GPS ICD 
200 is enought to implement a GPS receiver (assuming the RF section is 
there or simple).

Cheers,
Magnus




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