RTK fix issue in SimpleRTK2B MR KIT

Q&A forumRTK fix issue in SimpleRTK2B MR KIT
paoloB asked 1 month ago

Hello,
I’m new in GPS world and I’m testing a SimpleRTK2B Starter Kit MR (S/N 1919) with little success.
What happens is this:
– I power up the BASE station. It is in open sky position, stable position, satellites at 40/50 DB
– The BASE begins survey and after a few seconds I see the RTCM3 messages starting to flow
on the XBEE-USB connector of the ROVER (using u-connect). ROVER is close to the BASE.
Messages look like the ones in this post:
https://www.ardusimple.com/question/many-unknown-rtcm-messages-over-xbee/?ans-page=2
– On the ROVER the Fix type then goes from 3D to 3D/DGNSS/FLOAT for a while (about 1 minute)
– But suddenly the Fix mode on ROVER goes back to 3D (and no more goes to high precision).
I checked the “Age of DGNSS Correction” value on GxGGA–GNGGA. It stays on 1/2 sec
for a while, then starts increasing and when arrives to 60 the ROVER goes back to
3D Fix loosing the correction.
– The RTCM3 messages keep flowing on the XBEE-USB and the BASE completes the Survey
and goes to TIME mode.
– Leds on both station are blinking as expected
– If I send a Coldstart command to BASE, the sequence is repeated.
Both stations have been updated to 1.12FW and then I used the configurations
taken from the Github repo.
Using NTRIP, ROVER works fine and is stable in 3D/DGNSS/FLOAT/FIXED mode
I guess it is a communication/misalignment issue: does anyone have an idea of
how can I solve it?
Kind regards.

Ardusimple Staff replied 1 month ago

Hi PaoloB,
A few questions to try to troubleshoot your case:
1. Did the system work as originally sent with FW1.11 and pre-configured?
2. Did you load the configuration files using the “8/M8” configuration file option?
3. Do you enable additional messages on base and/or rover?

paoloB replied 4 weeks ago

Ok, now it apparently works.
What i did on BASE is:
– Reverted BASE to default configuration
– Downloaded BASE configuration, taken from Github repo. In “8/M8” mode.
Then:
– Disabled GALILEO
– Increased CFG-MSGOUT-RTCM_3X_TYPE1005_UART2 1005 send rate to 5 (secs?)

After an 2 hours DGNSS is still working.

But on the XBEE-USB I still see some “Unknown” messages (see below 2 examples).
Can these reduce the performances ?

??:??:?? 0000 D3 00 59 46 40 00 0C 14 87 7C 00 00 00 18 01 C0
0010 E0 00 00 00 20 00 00 00 7F AA 27 A7 A8 A4 28 AC
0020 A8 13 0B 9F 2D 34 D4 D7 12 71 60 00 5E 28 00 2D
0030 40 BD 58 3C 2E 73 22 2F 05 C8 00 2B 76 13 F1 D8
0040 2D 7F E1 78 D4 00 E7 DD F3 C1 88 2D 56 C0 B9 AD
0050 7F FF FF F7 80 55 55 B5 DF 5C 37
??:??:?? 0000 D3 00 08 4C E0 00 8A 00 00 00 00 A8 F7 2A

This is how traffic looks:

??:??:?? [15:20:10.801] R -> RTCM3 1230, Size 14, ‘GLONASS code-phase biases’
??:??:?? [15:20:10.801] R -> RTCM3 1005, Size 25, ‘Stationary RTK reference station ARP’
??:??:?? [15:20:11.738] R -> RTCM3 1074, Size 173, ‘GPS MSM4’
??:??:?? [15:20:11.738] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’
??:??:?? [15:20:12.613] R -> UNKNOWN ???, Size 87, ‘UNKNOWN’
??:??:?? [15:20:12.613] R -> RTCM3 1074, Size 173, ‘GPS MSM4’
??:??:?? [15:20:12.675] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’
??:??:?? [15:20:12.675] R -> RTCM3 1124, Size 103, ‘BeiDou MSM4’
??:??:?? [15:20:12.675] R -> RTCM3 1230, Size 14, ‘GLONASS code-phase biases’
(…)
??:??:?? [15:20:15.675] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’
??:??:?? [15:20:15.675] R -> RTCM3 1124, Size 95, ‘BeiDou MSM4’
??:??:?? [15:20:15.675] R -> RTCM3 1230, Size 14, ‘GLONASS code-phase biases’
??:??:?? [15:20:16.674] R -> UNKNOWN ???, Size 17, ‘UNKNOWN’
??:??:?? [15:20:16.674] R -> RTCM3 1074, Size 173, ‘GPS MSM4’
??:??:?? [15:20:16.674] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’
??:??:?? [15:20:16.674] R -> RTCM3 1124, Size 95, ‘BeiDou MSM4’
??:??:?? [15:20:16.674] R -> RTCM3 1230, Size 14, ‘GLONASS code-phase biases’
??:??:?? [15:20:17.612] R -> RTCM3 1074, Size 173, ‘GPS MSM4’
??:??:?? [15:20:17.674] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’
??:??:?? [15:20:17.674] R -> RTCM3 1124, Size 95, ‘BeiDou MSM4’
??:??:?? [15:20:18.674] R -> UNKNOWN ???, Size 9, ‘UNKNOWN’
??:??:?? [15:20:18.674] R -> RTCM3 1074, Size 173, ‘GPS MSM4’
??:??:?? [15:20:18.674] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’
??:??:?? [15:20:18.674] R -> RTCM3 1124, Size 95, ‘BeiDou MSM4’
??:??:?? [15:20:18.737] R -> RTCM3 1230, Size 14, ‘GLONASS code-phase biases’
??:??:?? [15:20:19.674] R -> RTCM3 1074, Size 173, ‘GPS MSM4’
??:??:?? [15:20:19.674] R -> RTCM3 1084, Size 144, ‘GLONASS MSM4’

1005 is appearing only sometimes, not at a regular pace.

Is it ok or there is still something to improve in the XBEE communication ?

Kind regards.

0 Answers