Weird GPS problems

Posted by Anton Khrapov on January 3, 2015 at 4:45am

Hi all,

I'm experiencing some weird problem with GPS.

I have used my APM on a plane with no problems. GPS (MTK one, from Adafruit) is hard-wired (soldered to the board directly).

Now I want to use this APM with GPS on my hexa. Nothing was changed but firmware on APM board. It sits next to my laptop with only GPS and RX connected. Power is supplied from USB. The problem is, there is no GPS lock AT ALL. If I flash arduplane back, GPS comes back ok. Arducopter - no GPS.

Any idea on what that might be?

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Replies

  • Artem January 3, 2015 at 10:06am

    If you are running AC3.2 NMEA support was dropped to make enoegh space for the main code. If you are using MTK GPS you need to get AC code from github and manually compile it with enabled nmea and disabled ublox disabled, or flash AC 3.1.5 ...... For APM there is no critical difference between that and 3.2. But I would get a pixhawk EKF is too much of a food thing to miss :) 

    • Anton Khrapov > Artem January 3, 2015 at 4:58pm
      I suspected something like that, but my confusion was caused by gps working on latest version of arduplane. I did not think they are THAT MUCH different.
    • Artem > Anton Khrapov January 3, 2015 at 11:04pm

      Прошивка для крыла занимает немного меньше места. 

    • Anton Khrapov > Artem January 4, 2015 at 5:22am

      Что-то делаю всё по инструкции, но, что бы я ни делал, IDE ругается, что код слишком большой :(

    • Artem > Anton Khrapov January 5, 2015 at 11:18am

      Ты не забыл комментнуть #define ublox? 

    • Anton Khrapov > Artem January 6, 2015 at 3:41pm

      Эээ... Поиск "#define ublox" по всем файлам выдаёт только три результата в библиотеках GPS, и все они являются только частью чего-то большего (типа #define ublox_msg или что-то в этом роде).

      Интересно, что даже неизменённый код, скачанный с сайта, при компилировании значительно больше, чем нужно. Для крыла тоже.

    • Artem > Anton Khrapov January 6, 2015 at 3:57pm

      там компилировать нужно в особой версии Arduino IDE

      скачай здесь http://dev.ardupilot.com/

      http://dev.ardupilot.com/wiki/building-ardupilot-with-arduino-windows/

       ask randy on the AC3.2 thread about the correct place where to comment. maybe it is  #define use ublox or something like that. 

    • Anton Khrapov > Artem January 6, 2015 at 4:01pm

      Да, да. Я по инструкции делаю.

      Пробовал и особую версию, и Atmel Studio. Результат один - компилятор ругается, что результат больше, чем влезет на мегу.

    • Anton Khrapov > Artem January 3, 2015 at 11:19pm

      Хоть бы предупреждали, что ли...

      Правильно ли я понимаю, что для ковыряния в исходниках нужна старая версия Arduino IDE? Там сложно поменять GPS на NMEA? Или там всё уже прописано, просто значение сменить нужно у переменной где-то?

  • Robert January 3, 2015 at 6:32am

    I'll try helping out by pointing out problems that I had with GPS in my experience.

    1. Is your software updated?
    2. Do you have other boards that might interfere with the GPS signal by introducing large amounts of electromagnetic fields?     (This actually happens if using poorly made boards, so you might wanna try to place your dog bowl onto it to fix it...actually don't try that)
    3. This might sound stupid, but is your system sufficiently distant from walls or large objects?

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