RTKDOP
DOP values for the satellites used in the RTK solution
|
Platform: |
OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7 |
The RTKDOP log contains the Dilution Of Precision (DOP) values for the satellites being used in the RTK solution. Note that unlike the PSRDOP log, the RTKDOP log is synchronous. DOP values will be calculated at the requested rate, up to a maximum rate of 1 Hz.
DOP values are a measure of the solution strength. Essentially, the DOPs reflect the geometry of the satellites used in the solution. Solutions with good counts of well-distributed satellites will have low DOPs and should be accurate and reliable. Solutions with fewer or poorly-distributed satellites will have high DOPs and be less accurate and reliable. As a rough guideline, PDOP values less than 4 imply a solution with reasonable geometry.
There can be many reasons for high DOP values. The most common reason is that there are obstructions limiting satellite visibility. Even if satellites are visible and being tracked they might still not be used in the solution if, for example, they are unhealthy or there aren't corrections available for them. The RTKSATS log will inform which satellites are being tracked and explain why a tracked satellite is not used in the solution.
The DOPs do not consider that different satellites or signals will be weighted differently in the solution. Therefore, they do not completely reflect the solution quality. Ultimately, the standard deviations reported in the RTKPOS log are the best reflection of the solution accuracy.
Message ID: 952
Log Type: Synch
Recommended Input:
log rtkdopa ontime 10
ASCII Example:
#RTKDOPA,USB1,0,66.5,FINESTEERING,2211,234163.000,02000020,b42b,16809;1.3390,1.0580,0.6760,0.8610,0.5340,5.0,16,17,3,6,12,19,2,24,14,1,46,57,38,47,45,55,56*6757f996
|
Field |
Field type |
Description |
Format |
Binary Bytes |
Binary Offset |
|
1 |
Log header |
RTKDOP header For information about log headers, see ASCII, Abbreviated ASCII or Binary. |
|
H |
0 |
|
2 |
GDOP |
Geometric DOP |
Float |
4 |
H |
|
3 |
PDOP |
Position DOP |
Float |
4 |
H+4 |
|
4 |
HDOP |
Horizontal DOP |
Float |
4 |
H+8 |
|
5 |
HTDOP |
Horizontal and time DOP |
Float |
4 |
H+12 |
|
6 |
TDOP |
GPS Time DOP |
Float |
4 |
H+16 |
|
7 |
elev mask |
GPS elevation mask angle |
Float |
4 |
H+20 |
|
8 |
#sats |
Number of satellites to follow |
Ulong |
4 |
H+24 |
|
9 |
sats |
Satellites in use at time of calculation |
Ulong |
4 |
H+28 |
|
10 |
Next satellite offset = H+28+(#sats * 4) |
||||
|
11 |
xxxx |
32-bit CRC (ASCII and Binary only) |
Ulong |
4 |
H+28+(#sats * 4) |
|
12 |
[CR][LF] |
Sentence terminator (ASCII only) |
- |
- |
- |