Import of GPS Ephemerides and pseudoranges from precise GPS+GLONASS to Espruino devices- new project

[espruino-discuss3]

Posted at 2023-09-14 by bart

Hi!
I have started a new project: to Import GPS Ephemerides and pseudoranges from precise GPS+GLONASS to Espruino devices. Goal of the project: to make SPP iterative positioning algorithm in espruino device by using a least squares method (single point positioning - SPP).
1 step. we are going to get raw ephemerides and computed satellite coordinates of GPS and GLONASS satellites from precise GPS+GLONASS receiver (Novatel Flexpak6). We worked out synchronisation problem of measured distances (pseudoranges) and calcullation of satellite coordinates for a moment when signal was sent by the satellites. also SBAS data (corrections for L1 frequencies for both GPS+GLONASS can be used in project too). We worked out how to synchronise all data even with centimeter level of accuracy by using a Spirent signal generator and Novatel Flexpak6 for GPS+GLONASS. Thus we achieved ultimate control over GPS+GLONASS+Galileo+BeiDou+SBAS data by using other 4-constellation receivers equipped with SBAS too.

2. Navigation GPS+GLONASS messages (ephemerides and almanac) will be sent to Espruino devices such as Bangle1, Bangle2, Pixls.js by using Raspberry PI. We have our good data logger made and working perfectly in Raspberry Pi4 for ephemerides and pseudoranges and it was written in Python.

3. after we transfer ephemerides and pseudoranges from Novatel to Espruino devices, we will make iterative single point positioning algorithm in Espruino. we have our great working codes written in Matlab and Python so we have good reference starting point.

4. i am not sure that we want to compare bangle's GPS to novatel GPS because I dont see any reason to do that. . we know how to operate Gps in Espruino but it is only nmea data (novatel uses both raw and nmea)

we don't want Gps raw data from espruino watches because we don't rely on it and we don't have control over gps +glonass data in espruino and we don't have good documentation how to synchronise all data -> check no.1 we worked out this problem but in novatel GNSS

ADDITIONAL GOAL:
5. After we transfer a Navigation Message and Pseudorange values to Espruino devices, we are going to program our own Cubic positioning algorithm, invented in 2012.
Cubic algorithm is UNPUBLISHED and what I can only say it is the only algorithm in the World among about 50 existing positioning algorithms and Cubic algorithm can use additional cubic units [m^3] to correct pseudoranges. In result better accuracy is achieved. We will make it working on Bangle1, Bangle2, and Pixl.js (but GNSS data is taken mostly from Novatel GNSS)

[gfwilliams]

Posted at 2023-09-15 by @gfwilliams

This sounds really interesting - thanks for sharing!

From my point of view, Bangle.js 2 would be very interesting as the receiver doesn't appear to do quite as well as Bangle.js 1 or standalone ones.

Not sure if you saw it but we have some info on communicating with the GPS at https://www.espruino.com/Bangle.js2+Technical#gps and you can turn on the output of extra GPS data that might be interesting with the $PCAS03 command