Hello,
we recently started building an own RTK base for test purposes and
seem to have some issues with it. We want to test a simple RTK
base-RTK rover scenario.
About the setup: As hardware we use a raspberry pi 3b+ that is
connected to a ublox-M8P via USB. The antenna and the other components
are all installed ontop of the building. The raspberry has the latest
version of Raspberry Pi OS (Bullseye). I installed the latest gpsd
version (3.24.1), RTKLIB (https://github.com/tomojitakasu/RTKLIB.git)
and ntripcaster (https://github.com/roice/ntripcaster).
To get the base started I ran a few ubxtool commands:
ubxtool -e RTCM3 -P 20.30 -f /dev/ttyACM0
ubxtool -d NMEA -P 20.30 -f /dev/ttyACM0
ubxtool -p MODEL,2 -P 20.30 -f /dev/ttyACM0
ubxtool -e PPS -P 20.30 -f /dev/ttyACM0
ubxtool -e SURVEYIN3,100,2000 -P 20.30 -f /dev/ttyACM0
It takes around 7 1/2 hours to reach the accuracy of 2000 (20cm
right?). So that seems right compared to the mentions in the ubxtool
file.
However the position is far from right.
root@rtk-base ~ # ubxtool -p NAV-SVIN -P 20.30 -f /dev/ttyACM0
UBX-NAV-SVIN:
version 0 reserved1[0 0 0] iTOW 208863000 dur 27251
meanX 371818636 meanY 75095561 meanZ 511048862
meanXHP 33 meanYHP 1 meanZHP -42 reserved2 0 meanAcc 2000
obs 27247 valid 1 active 0
Using https://www.oc.nps.edu/oc2902w/coord/llhxyz.htm or any other
ECEF to LLH translator the values are far off from where we actually are.
Results from the website:
Latitude : 53.41551 deg N
Longitude : 11.41833 deg E
"Actual" Position:
Latitude: 53.59931 11.41833