SETDIFFCODEBIASES
Sets satellite differential code biases
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Platform: |
OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7, SMART2 |
Changing the biases may negatively affect positioning accuracy. NovAtel recommends that only advanced users modify the biases.
Use this command to set the differential code biases that correct pseudorange errors affecting the L1/L2 ionospheric corrections. Bias values are restricted to between -10 ns and +10 ns. A set of biases is included in the firmware and use of the biases is enabled by default.
The receiver uses the C/A code on L1 and the P code on L2 to calculate a dual-frequency ionospheric correction. However, the GNSS clock corrections are broadcast as if the P codes on both L1 and L2 are used to calculate this correction. The biases account for the differences between the P and C/A codes on L1 and improve the estimate of the ionospheric correction.
The biases are calculated by the International GNSS Service (IGS). Calculation details, analysis and results are available at http://aiuws.unibe.ch/spec/dcb.php. The most recent 30 day average bias values can be downloaded from http://ftp.aiub.unibe.ch/CODE/CODE_FULL.DCB.
Message ID: 687
Abbreviated ASCII Syntax:
SETDIFFCODEBIASES bias_type biases
ASCII Example:
<SETDIFFCODEBIASES COM1 2 91.0 UNKNOWN 0 0.470 02440020 365b 32768
< GPS_C1P1 1.302 -1.326 1.360 1.649 1.357 1.586 0.776 -0.079 -0.123 0.888 -0.321 0.718 0.527 -0.720 1.193 -1.331 0.828 -1.061 -2.497 -2.106 -1.979 -2.747 -0.254 1.202 -0.716 0.077 -0.180 -1.059 1.269 -0.481 0.734 1.516 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
<SETDIFFCODEBIASES COM1 1 91.0 UNKNOWN 0 0.471 02440020 365b 32768
< GLONASS_C1P1 -0.092 0.381 0.581 1.033 0.642 -0.561 0.794 0.899 0.380 -0.832 -0.358 -0.606 -2.181 0.023 1.135 0.346 0.009 0.384 -1.394 0.224 -0.022 -0.824 -0.133 -0.437 0.000 0.608 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
<SETDIFFCODEBIASES COM1 0 91.0 UNKNOWN 0 0.473 02440020 365b 32768
< GPS_C2P2 1.358 0.000 -0.381 0.000 -0.344 -0.707 0.306 -1.068 0.624 1.480 0.000 -0.401 0.000 0.000 -0.169 0.0 00 0.236 0.000 0.000 0.000 0.000 0.000 0.000 0.051 -0.711 1.082 -0.128 0.000 -0.101 -0.483 -0.630 -0.015 0.000 0.0 00 0.000 0.000 0.000 0.000 0.000 0.000
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Field |
Field Type |
ASCII Value |
Binary Value |
Description |
Format |
Binary Bytes |
Binary Offset |
|
1 |
Command header |
- |
- |
SETDIFFCODEBIASES header This field contains the command name for abbreviated ASCII or the message header for ASCII or Binary. |
- |
H |
0 |
|
2 |
bias_type |
GPS_C1P1 |
0 |
Code pair to which biases refer |
Enum |
4 |
H |
|
GPS_C2P2 |
1 |
||||||
|
GLONASS_C1P1 |
2 |
||||||
|
3 |
biases |
-10 to +10 ns |
Array of 40 biases (ns) |
Float[40] |
160 |
H+4 |
|