Connecting a GPS module

[W7DGP]

Reading through the Full Test of APRS, this statement really caught my attention:
"If an optional GPS module is wired to J12 on the Main board and has a GPS lock, the GPS coordinates from the module will be listed in the payload string and also the APRS coordinates."
My questions: Is there a recommended GPS module? Is there info on how to implement this? Maybe just connect it up and the APRS packet will use the GPS module rather than the coordinates entered using config.

[alanbjohnston]

Hi Larry,

Fully documenting this is on my ToDo list but I haven't done it yet.

Here's some info for you until I write up the Wiki page:

The CubeSatSim v2 software supports a GPS sensor. It just needs to be added to the Main board.

First, you need to purchase a serial GPS module. For example, these ones work:

https://www.amazon.com/HiLetgo-GY-NEO6MV2-Controller-Ceramic-Antenna/dp/B01D1D0F5M

https://www.amazon.com/dp/B09LQDG1HY

Three wires are needed to be wired to J12 on the Main PCB.

3.3V <-> supplies power to the GPS module on Vcc pin.
GND <-> ground for the power to the GPS module on GND pin.
RXD <-> connected to the Transmit data TX pin of the GPS module.

Once you wire it up, the best way to test the GPS sensor is to connect a micro USB cable to the Raspberry Pi Pico and use the Arduino IDE Serial Monitor to see the GPS messages.

Alternatively, you can log into the Pi Zero 2 and type the command CubeSatSim/config -p to see the coordinates listed after “GPS”

The GPS antenna will need to either be outdoors with a good view of the sky or near a window. It can take up to 10 minutes for a GPS module to get a location lock. Many GPS modules have a “lock” LED which illuminates or blinks when it has a good location lock.

You will see GPS messages and eventually the three numbers after GPS will be non-zero.

The GPS coordinates will then be used in APRS packets.

An APRS application that graphs packets can be used, such as the APRS decoder in the WebSDR OpenWebRX. Alternatively, you can copy the latitude and longitude from the Direwolf or SoundModem output and graph it using an online tool.

Good luck!

Alan

[W7DGP]

Thank you Alan for the quick reply. This seems all the info I need to give this a shot. I have some experience with GPS modules on two other projects and I'm looking forward to adding GPS to the cubesatsim. My underlying interest is in APRS. I started from zero this summer to getting my Anytone HT to "squak" packets and receive and decode them. I'm beginning to understand APRS and I'm excited to continue investigating.