In this topic I want to introduce my project as Brian asked me to do.
In an earlier project (handheld bluetooth RTK and NTRIP base station) I used the SkyTraQ receiver NS-HP-GN2 (NS-HP-GN2 : PX1122R Multi-Band Quad-GNSS RTK Breakout Board - NavSpark Store). This is a GNSS receiver supporting
GPS L1 / L2C
Galileo E1 / E5b
Beidou B1I / B2I
GLONASS L1 / L2
QZSS L1 / L2C
with RTCM base stream input and NMEA output. It also could be configured for use as base station to output RTCM or SkyTraQRaw data or “Precisely Kinematic Base” to get high accurate heading on moving vehicles. The NS-HP-GN2 is a breakout board based on the PX1122R chip wich starts from 99$ (125$ as breakout board) and is therefor a bit cheaper than the often used simpleRTK boards.
Across this summer I’m planning to build a dual antenna setup using two of these receivers. It should be easily configured to send a RTCM stream to the first receiver, give the output to the second receiver and take the output from second receiver to AgOpenGPS. Next to the “normal” NMEA stream you get $PSTI,032,… messages wich include heading as angle between the vector of the two receivers and north, the “upProjection” wich is the difference in altitude of both receivers and the “baselineLength” wich is the distance of the receivers. I plan to mount two antennas next to each other on the roof (with distance as far as possible). You get the actual heading of the tractor with adding 90 degree to the heading from output and you could calculate the roll from upProjection and baselineLength.
What I already did is coding the parsing of the $PSTI stream in AgOpenGPS which you could find under this PullRequest and added by Brian in this Commit:
I tested the code yesterday inside AgOpenGPS (Visual Studio) with a setup of two NS-HP-GN2 receivers on my working desk to get the $PSTI,032,… output and it worked so far (I got values for roll and heading which looked properly), but I cannot say anything about accuracy and reliability yet as I have only had float RTK on that setup.
I will post the progress in this topic if you like.