akshaykulkarni07
commented
4 years ago - We need to interface a GPS module to get the global coordinates of the robot. Accordingly, we bought Ublox M8N GPS module.
- There is an extra JST connector on it (with 2 pins). Ignore that when interfacing with Arduino. However, that will be used if interfacing with Pixhawk FC or similar hardware which expects 6 pins instead of 4 for GPS.
- Also, remember that most GPS modules work on 3.3V, so we can't connect Rx and Tx pins of Arduino (which are 5V) directly. It might work directly but safer to use a logic level converter (or simply a resistor divider circuit). Also, remember to use common ground for everything.
- Note that after powering on the GPS module, it takes around 30 seconds to 1 minute to get the GPS fix. So, allow that much time before labelling the module as broken.
- Tried using this library. It has good instructions. The basic code given in this produces UTC time, date and latitude, longitude, altitude, speed information as a demo. However, when using outdoors (on the road outside the Academic Block), it doesn't work correctly. It gives the UTC time and date correctly but doesn't give any position information. The location used for testing is pretty much open to the sky and time of testing was around 1:15 AM IST.
- This answer explains why time can be received even without GPS fix. If you don't want to read that, it's basically because each satellite transmits time (on it's own), whereas for position inforamtion, you need at least 3 satellites to get the GPS fix. Also, it is possible that time is received before GPS fix (same reason). So, we can conclude that GPS fix is difficult in front of Academic Block (need to experiment more of course), and also that the GPS module is not broken.
- Need to test in more places. Not done immediately since it's 1:30 AM and don't want to roam around campus alone at night (lot of wild animals around :grimacing: :joy:). Will be done in the morning/afternoon (today itself).
patilunmesh