Adding a GPS Rocket Tracker to my openSource altimeters (for Android devices)

[bdureau]

Few years ago I started logging GPS coordinates as part of the rocket flight on my stm32 Altimeter. I am now also adding GPS tracking and I am releasing it open Source
I have been looking at the previous tracker that were written by various people and unfortunately they are no longer compatible so I am re-writing from scratch. I have re-used the rocket track icon (from Kevin) because it looks cool but this is work in progress and I have not implemented all functionalities yet. This is work in progress!!!


Code for the front end is
https://github.com/bdureau/BearConsole2
backend
https://github.com/bdureau/AltiGPS

 

[billdz]

Thanks much for developing this, much needed.

 

[thzero]

Nice. I have too been rewriting from scratch. But I chose to try it with flutter (for eventual use on iOS).. but my lord, that been painful

 

[bdureau]

This is what the tracker looks like. I am testing different GPS modules to see which one is best and to find a compromise between price and reliability. So far I have bought 4 x 6M GPS modules and one was unable to acquire satellites. I have bought a couple of 7M modules and they seam to start acquiring GPS a lot faster. I gave a couple of trackers to some rocketers in my club so that they we can start flying them

 

[bdureau]

I am now testing some smaller GPS modules that can be soldered on a board. Plan is to make a small GPS tracker

 

[kenstarr]

Looks fantastic! Keep up the good work.
Ken

 

[OverTheTop]

Don't expect as much from the smaller GPS modules as they are not as sensitive as the larger ones, from what I have found. Also if you keep your telemetry transmitter further away from the GPS antenna it will lock quicker and give better position reporting. Interference from the telemetry Tx can induce receiver desensitisation and clock jitter.

BTW, GPS refers to the American Navstar system in particular. A better term to use these days is GNSS, Global Navigation Satellite System. This includes Navstar, Galileo, Beidou, GLONASS and other systems. Many of the GNSS receivers can receive more than one constellation, providing greater accuracy due to working on different frequencies and tracking more satellites.

 

[bdureau]

Don't expect as much from the smaller GPS modules as they are not as sensitive as the larger ones, from what I have found. Also if you keep your telemetry transmitter further away from the GPS antenna it will lock quicker and give better position reporting. Interference from the telemetry Tx can induce receiver desensitisation and clock jitter.

yes after testing it is less sensitive than those with larger antennas.
For the telemetry I am using various modules to see which one is best and which one less disturb the GNSS
The objective is to have something affordable ( less than 50 euros)

 

[bdureau]

Ok it has been few months and I have made some progress. I have added all the GPS functionalities to my BearConsole application
Here is a quick demo


It is currently using Google API which means it is not free and I cannot have it on the app store.
I want my code to remain open source so I am currently looking at some alternatives such as openstreetmap
https://github.com/osmdroid/osmdroid/wiki
If anybody as some suggestions for a Google Map API replacement

 

[thzero]

Yes they sorta borked that and made it harder to understand. Openmap is ok.. I've integrated it with a Flutter app.

But... Maps isn't necessarily costs, as long as not using street view or loading via mapid it seems to be zero cost for native mobile maps.
https://developers.google.com/maps/documentation/android-sdk/usage-and-billing

 

[bdureau]

What I know is that whenever I use the debug APK it works and whenever I use the release APK it does not display the map.
I have had a look at Openstreetmap and it looks easy to use. I will do a prototype

 

[Ben59]

Well done Boris

 

[bdureau]

I ended up making a smaller GPS tracker board that only track the rocket. It no longer record the flight.
Available in 433Mhz and 900Mhz


and wrote a dedicated application using OpenMap
https://github.com/bdureau/SimpleModelTracker
It is a very simple tracker and it works really well so far. I need to test it on a Rocket

 

[LithosphereRocketry]

I ended up making a smaller GPS tracker board that only track the rocket. It no longer record the flight.
Available in 433Mhz and 900Mhz
View attachment 571552

and wrote a dedicated application using OpenMap
https://github.com/bdureau/SimpleModelTracker
It is a very simple tracker and it works really well so far. I need to test it on a Rocket

Would you consider adding an Openlog pinout similar to the Eggfinder boards so that people who want logging can add their own?

 

[bdureau]

I don't think so because you can log the flight if you run it on my AltiMulti with the addition of a GPS module and a special firmware. This is really for small rockets when you just want to track.

 

[jhill9693]

Happy to help test side by side with Eggfinder products for comparison.

 

[bdureau]

Well the Android software should be compatible with GPS some other GPS tracker