GPS Racer: worklog #3

GPS Racer project is almost done. Last week I’ve assembled al the electronics I had and maidened it over the weekend with partial success.

Build is still missing FPV gear: RunCam Owl and VTX did not yet arrived so. Without them, final specification is:

  • Frame: Realacc X6R
  • Motors: Emax RS2205 2300KV
  • ESC: FVT LittleBee 30A
  • Propellers: Gemfan 6030
  • Flight Controller: Airbot Omnibus F4 Pro with INAV 1.6
  • PDB: Matek PDB-XT60
  • RC link: FrSky X4R-SB with SmartPort over SmartPort inverter
  • GPS: Beitian BN-880

GPS Racer 6" quadcopter

I must admit: that tower in the front, while required for magnetometer to work properly, is one ugly piece of plastic. I really have a talent for building ugly looking UAVs and this is not an exception.

Since I had no FPV over the weekend yet, I was flying only GPS assisted modes. Must admit, that was fun. Position Hold and Altitude Hold was rock steady. Very little if none wobble on descend. But the biggest fun was high speed CRUISE and RTH. By high speed I mean 15m/s (54km/h). Seeing how UAV goes by itslef at 54km/h and then breaks hard to landing is little scary.

Unfortunately, I was unable to test waypoints navigation. GPS module (Beitian BN-880 that I just a few days ago called the best for INAV) died. Probable cause: voltage regulator burned. I have a spare, so this weekend second part of testing…

12 thoughts on “GPS Racer: worklog #3

  1. Looks really nice. I am currently waiting for parts for similar build. I might try iNav. Looks promising. Happy flying.

  2. Hi, I’ve been working on a similar project for awhile. Same board as well. Did you have to change any of the INAV settings for your POSHOLD to work? I used their preset for the 5″ racer, but didn’t change settings for nav PID. It won’t sit still, just jogs around within a 1 meter radius, constantly correcting and not stabilizing ever.

    1. All NAV PIDs are at default. This is also 5″ racer preset, I only increased gyro update frequency and PID loop frequency since F4 has enough power for that.

      Maybe it’s GPS module issue or magnetometer is too close to power cables

      1. Thanks for the input. My gps is on a mast like the mag. What did you increase gyro and loop frequency to? Might help me.

          1. I wish so badly that were the case. The ACC is dialed. The thing flies perfectly…until poshold is activated. I’m gonna try a different GPS, though the ublox neo-m8n should be adequate – I’m gonna check the BN-880 since it seems to work for you and I can’t figure out if it’s something else. I’m curious also, though – did you cover your baro much and are you getting accurate readings? Even with mine covered the thing ranges about 1-2m up and down (while it twitches back and forth within a 1m radius). Baro doesn’t have to be calibrated, right?

  3. Im building a similar quad, went with Gartt LT 2000KV motors with 6030 props and Littlebee 20A pros … I see you used 30A, do you think 20A might be too weak?

  4. Great build because it works. I’ll try INAV on a racer, too.
    What is your config for the compass of the BN880? 0° 90° 180° 270° flip on/off?
    I currently have an old WarpQuad with F1 FLIP32 board using the onboard mag but it toilet bowls badly. I plan to convert my small 155 racer with F3 Omnibus to GPS 🙂

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