I am working on developing a high accuracy outdoor localization system. For tests, I have bought two SparkFun ZED-F9P u-blox modules. I have the following queries:
a) Can a single base station control multiple rovers.
b) Can the RTCM correction data (obtained from a base station) be stored and post-processed on the rover data. Please let me know if there are any tutorials on this topic.
c) Can NEO-M9N process (post-process) RTCM data as it is mentioned it supports RTCM protocols over UART or I2C interfaces
a) Yes. Any rover with a 10km baseline can use the RTCM coming from a base station.
b) I’ve never heard of anyone logging RTCM and post processing. Normally a base logs RAWX and SFRBX messages for post processing. A ZED is very capable of producing both RTCM for live Rovers and RAWX/SFRBX recorded to SD (or other) for later.
c) I don’t fully understand your question but no, that’s not really how you use RTCM. A NEO-M9N fed with old RTCM data will attempt to use it on its real-time satellite data and just output a bad fix.
Thanks a lot, Sparky; I am new in this field and my knowledge is limited. I want to achieve cm level accuracy of my nodes using NEO-M9N/ZED-F9P . However, I don’t need the cm level accuracy in real-time, so I don’t want to stream correction data from the base to the rover. My rovers are within the range of CORS networks and I can generate the correction data. So, I am asking if the positioning data of the rovers can be updated to achieve cm level accuracy in post-processing.
The NEO-M9N is not capable of high precision. It’s accuracy is limited to about 1.5m (but you may see slightly better). The ZED is a very different receiver with a lot more capabilities (hence the price difference).
Post processing is normally done with RAWX/SFRBX and only the higher end modules are capable of outputting this information. I think there was a lower cost NEO-M8N(?) module that users found would output RAWX but it was still limited to L1 band reception so it was still no-so-great.
My rovers are within the range of CORS networks and I can generate the correction data. So, I am asking if the positioning data of the rovers can be updated to achieve cm level accuracy in post-processing.
With a ZED, absolutely. You would datalog the RAWX/SFRBX messages and post process with CORS. You could even do it in real time (if your CORS output RTCM).
I have tested the ZED-F9P board in u-centre software by feeding it correction data from an NTRIP server. I was able to achieve sub cm level accuracy. Now I want to move the entire system to ESP32. I want to connect multiple rovers with the NTRIP server. Can you please suggest some basic library to start with? The NTRIP server that is available requires a username, password, lat and long.
Also, is there any option to put the GPS to deep sleep and wake it up using ESP32.