Trying to catch GPS coordinates

Navio / Edge Hardware
1

Hello,

I’m trying to aquire GPS coordinates from APM. I tried to use some methods from the code without success, then I tried to include the Ublox library at APM to get this coordinates. I had success using it, but what I really want is to get values for X and Y displacements in meters, is it possible to get? I also would like to have the NED speeds, if its possible.

thank you,

Rafael

2

Hi Rafael,
Easiest way to get coordinates from APM is to read them from MAVLink using MAVProxy or your own code.

3

Hi mikhailavkhimenia,

Thank you for helping, but I don’t understand how to catch the mavproxy information in my code. what I saw at the documentation is that mavproxy sends information to a selected IP on network. I’m trying to catch the coordinates, put it together with another parameters and save it on a .CSV file at a directory in RPi.

what’s the best to do it? (I’m programing in C++)

4

APM (or MAVProxy) can send MAVLink on a local port, so you can read it directly on Raspberry.
You can open that port in C++, parse the MAVLink protocol and extract the coordinates from the corresponding GPS message.

5

Hello mikhailavkhimenia,

I followed this tutorial:
http://dronecode.github.io/MAVProxy/html/getting_started/download_and_installation.html#linux
and looked better in the developers enviroment:
http://dronecode.github.io/MAVProxy/html/development/mavdevenv.html

But I didn’t had success while installing mavproxy, when I type “python setup.py build install --user” I receive an error and I cannot install pymavlink and I’m not able to run MAVProxy because it cannot load the modules.

can you help me again?

6

I would make sure your raspi is up to date with upgrades and updates.

apt-get install upgrade
apt-get install update

Then try again.

7

The commands were fine, but I still cannot install the mavproxy.

I’m trying to use the functions inertial_nav.getposition() and inertial_nav.getvelocity()
I don’t receive de X and Y coordinates, only the Z. the velocities seems to be wrong too.

8

Hi!

I’ve been trying to figure out how to send MAVLink on local port and I am not sure how to do it. In particular, I would like to send MAVLink both to Mission Planner and to Raspberry Pi itself (to extract the coordinates parsing the protocol).

  • Do I need to use two telemetries when I start ArduCopter (i.e. -A for the GCS with Mission Planner and -C for the local port)?
  • Or do I need to send the MAVLink through Mission Planner?

I would really appreciate any help!!! :smile:

9

@mariagf there are numerous ways to do that, using two telemetry options may be the simplest of them. Just specify 127.0.0.1 as IP port for one of telemetries.

10

Great! I will try that then!

12

Hey! Did you managed to obtain the MAVlink data? How?