[teqc] about tanslation from tirmble raw data to rinex

[Lou Estey]

Dear Mooketsi Segobye,

> I used teqc to translate trimble GPS raw data(*.dat) to RINEX 2.10 
> format. The converted RINEX file's header shows 6(L1L2C1P2P1D1) 
> observation types but the data records part only shows 5 obs types.
> 
>    6    L1    L2    C1    P2    P1    D1                  # / TYPES OF 
> OBSERV
> SNR is mapped to RINEX snr flag value [0-9]                COMMENT
>  L1 & L2: min(max(int(snr_dBHz/6), 0), 9)                  COMMENT
>  2006    10    20     3    28   15.0000000     GPS         TIME OF FIRST 
> OBS
>                                                            END OF HEADER
> 06 10 20  3 28 15.0000000  0  8G 1G 3G13G16G19G23G25G31
>    298668.72758    221794.94856  22148784.5314   22148781.3404
>     -2494.7974
>   -355126.53158   -261295.18157  20789487.6724   20789484.4064
>      2923.0784
>   -452755.05556   -334931.77754  23652536.6644   23652532.8324
>      3765.4224

The .dat record 17 (the only .dat record containing GPS data that
teqc can read at this time) is structured so that only one pseudorange
per carrier frequency can be stored.  This goes back to even the
design of the original Trimble receivers and their firmware.  Thus for
L1, you will only see C1 or P1; P1 is antispoofing is off for the SV,
otherwise C1.  Likewise for the NetRS w/ L2C tracking enabled, for L2
you will only get C2 or P2; if L2C is available for the SV (currently
only PRN 17, I think) then C2, otherwise P2.  Above, you are showing
current data and antispoofing is on for all SVs, so you only get C1
and no P1.  (If one or more of the SVs flipped to antispoofing off for
a time -- which has happened, though very rarely now -- then the receiver
would automatically switch to logging P1 for those SVs.)

Now there is some very indirect evidence that I've received that for
Trimble's new GLONASS tracking receivers, the NetR5 and R8, that the
.dat for these receivers might be different.  But this appears to rely
on a .dat structure for which I have no documentation, and therefore
teqc can't read the .dat files from these receivers; you'd have to use
Trimble software to read the raw data files from these newer receivers.

Hope this helps,
--lou