I have an imaging board that needs to have GPS data to go along with the pictures it takes. I'd like to not have 2 GPS units on my vehicle and instead somehow output the GPS data that the APM2 has to this imaging board. Are there any available serial or other ports on the APM2 that I could add some code to send the GPS data out?
GPS data is included with the normal telemetry data coming out of the serial port for connection to the Xbee or other radio modem. All you need to do is grab the code from any of the OSD (on screen display) boards which will decode the format you need. The OSD boards are based on 328s, so just about any arduino could be loaded with the code as a go between. You really don't want to go mucking with the code on the APM, just use the OSD code, and have it connect to your other equipment and/or inlcude that code in you other device.
I could be wrong but I think stock APM code is using binary gps anyway, thus even if you messed with the APM code, you have to flash the gps so it uses nema text codes, then modify the APM code to use nema codes and then either port nema out gps out a serial or your right back at the solution I listed above using OSD firmware on a arduino to translate binary telem data to nema you are expecting.
I might be wrong about some of those details/names/codes, but that info was in some threads about guys having gps problems or trying to use other gps modules.
It's main components are an ATmega328P 8 bit microcontroller with an Arduino bootloader, and a MAX7456 monochrome on-screen display. Programming is done through an FTDI-compatible 6-pin cable.
The code is here:http://code.google.com/p/arducam-osd/wiki/minimosd
Actual firmware stuff here http://code.google.com/p/arducam-osd/wiki/Update_Firmware
So again, the best setup is just grab the mavlink data coming from either end of the xbee radios (ground or the air side at the APM). Either use an arduino or use this code in your display setup.
For stability and update purposes, leave the APM code stock and do the translation you need externally.
I have the same problem, and I think the OSD solution could be the easyest but isn´t the best.
Maybe we can use some APM out to duplicate GPS data and send it to the payload.
I was thinking.... If I conect the payload in parallel to the GPS port on the APM........?
It could work. Lets Try.!