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Document Title: 35
User’s Manual for the GPS Orion-S/-HD Receiver
Document No. Issue 1.0
GTN-MAN-0110 June 22, 2003
DLR/GSOCNo part of this document shall be reproduced in any form or disclosed to third parties without prior authorization.
4.4.1.8 F42 – Pseudorange, Carrier Phase and Range Rate (Raw)
Complementary to the smoothed measurements given in the F41 message, the F42 mes-
sage provide the unprocessed, raw pseudorange, carrier phase and range rate (Doppler)
measurements for the 12 tracking channels. All measurements are given in metric units (i.e.
[m], [m/s]).
MsgID Chars. Format Description
F42 505
Pseudorange, carrier phase and range rate (raw)
1
x <STX>
3
xxx Message Id (=F42)
4
xxxx GPS week
12
xxxxxx.xxxxx GPS seconds of week [s] (GPS time of observ. using current clock model)
2
xx GPS-UTC [s]
12
xx.xxxxxxxxx Clock offset [s]
Repeated for each of 12 channels
2
xx PRN
13
xxxxxxxxxx.xx Pseudorange [m] (unsmoothed)
14
sxxxxxxxxxx.xx Integrated carrier-phase [m]
9
sxxxxx.xx Range rate [m/s]
1
x Validity flag
2
xx Checksum
1
x <ETX>
Notes:
• The time tag of the measurements is identical to that of the associated navigation
data message. It is referred to a model clock that is continuously adjusted to GPS
time as part of the navigation solution. In an S/A free environment, this model clock
usually deviates by no more than 30 (0.1 µs) from the true GPS time.
• Representative accuracies amount to 0.4 m (pseudodrange), 0.7 mm (carrier phase)
and 8 cm/s (Doppler based range rate) for the Orion-S receiver. The HD version ex-
hibits a higher noise of the code (ca. 1 m), carrier phase (ca. 1.5 mm) and Doppler
measurements (ca. 30 cm/s) due to the relaxed loop bandwidths.
• Measurements are nominally collected once full frame lock has been achieved on the
tracking channel. In addition, measurements can already be provided in carrier lock if
a valid navigation solution is available to perform the required synchronization of raw
correlator readings. To prevent bad measurements from entering the navigation solu-
tion, measurements are only tagged valid from 10 s after frame lock onwards in the
Orion-S receiver.
Example:
<STX>F421139172840.0000013 0.071561082 3 24651987.05 -307413.396 -3259.220 5
23960883.83 +105549.919 +2365.530 6 22747854.11-111711119.850 +7410.090 9 2
2493872.10 -380366.985 -4080.44121 24261196.28 -628217.740 -6951.55118 228
61450.35 -333623.542 -6709.47123 23713839.06-113242044.709 -4595.36125 23786
025.64-111954989.319 +5637.95029 22797343.88-112616306.585 +926.33114 2158937
7.48 -162108.043 -1689.34115 20050705.60-114318812.585 -3365.58117 19685814.
19-113949616.991 -1146.1614A<ETX>