ENG-CANSAT-PICO-GPS
 | Page(s) en cours de traduction/élaboration. Page(s) under translation/construction |
Forewords
Transmitting the CanSat localisation while the parachute descent will, for sure, help you to find on the ground!
The CanSat GPS module use the GPS / GALILEO / GLONASS / QZSS satellite networks to calculate the current position.
The GPS module used a Patch Antenna made it very compact while still offering a -165 dBm sensitivity. The high sensitivity made it possible to detect the localisation signal even under bad conditions.
With the patch antenna already oriented to the sky, the module is ready to mount on the CanSat with a simple Grove cable!
Hot Start Localisation
What's make the difference of this GPS is its hot start capability.
The Hot Start requires a CR2032 coin cell to be inserted. Then the GPS module keeps an accurate time tracking making it possible to get satellite fix within 1 second!
Without the CR2032, the GPS module tries to locate the networks as it will do the very first time, this cold start may take up to 35 seconds (datasheet).
Technical details
- Supported Networks: GPS/GALILEO/GLONASS/QZSS;
- Channels: 33/99 channels
- Hardware support: MT3333
- Refresh Rate: 1-10Hz
- TTFF (Time To First Fix): 1s (hot start)/35s (cold start)
- Sensisivity: -165dBm
- Interface: UART, I2C
- Protocol: NMEA
- Voltage: 3-4.3V
- Antenna: ceramic patch antenna
- Size: 16x16mm. Height: 6.7mm
- Circular Error Probable: 3m(CEP)
- Speed accuracy: 0.1m/s
- PPS Accuracy: 20ns (PPS=Pulse Per Second)
- SBAS, EPO, EASY, always Locate, LOCUS
Installing the GPS library
The board is compatible with GPS-Ultimate MicroPython library (available on GitHub).
You can download and copy the library manually to your board from the Repository.
First, open the repository, then navigate to the file lib/adafruit_gps.py and lib/gps_config.py.
Follow the steps as describes in the "BMP280 library installation" to copy the GPS library files to your micropython board.
Once copied, you can also check the proper installation by typing from adafruit_gps import GPS .
The GPS-Ultimate library repository contains examples of usage. Do not hesitate to check them!
Connect CanSat GPS
Quite simple, just plug the grove cable to the Cansat-GPS and the other end to UART connector.
GPS code
Now we will load and executes the simpletest.py script. The script must be downloaded from the repository.
The script can be either executed from Thonny -OR- transfered to the Pico and executed directly on the microcontroler.
It will output the messages on the REPL/Shell (over the USB-serial connexion) when the GPS got a fix.
GPS test
The cansat-belgium-micropython repository contains a test-gps subfolder with demonstration script.
Wait the Fix
{{dbox-orange|GPS data will only be available when the GPS module got a fix.]]
The LED next to the GPS:
- Blinks while searching GPS network
- Lit (fixed) when synchronized with GPS Network.
Minimal test
- indiquer qu'il faut attendre le fix :::
| | Page(s) en cours de traduction/élaboration. Page(s) under translation/construction |
- showing the code and the result ::::::
Written by Meurisse D. for MCHobby