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GPS Reading Inaccuracy Problem

Posted by Aizzat on July 10, 2012 at 11:58pm

I have APM2. I tried to verify the location of my GPS.

What I found out is that at the same location GPS reading gives different value even though I am not moving my APM, it is just a static location. 

So, the problem comes when I want to calculate the distance from one point to another waypoint. It gives inaccurate reading. Any idea to overcome this problem ?

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Tags: apm20, gps, location, inaccurate
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Replies

  • Tersus GNSS December 11, 2015 at 6:07pm

    single point GPS is not suitable for this task,  you need differential GPS (SBAS, WAAS.) to get accuracy of 1m. then if you want the centimeter accuracy, you need RTK GPS. checkout our website: tersus-gnss.com; we are targeting low cost RTK for UAV. it's very stable and useful.

  • Ryan Jarvis November 25, 2015 at 6:08am

    Hello,

    Would a differential gps option be possible using the gps on an android device, or external gps on a laptop (used as a base station with radio telemetry).  Here are the changes that would probably be needed in mission planner:

    The software could show where the gps sensor is showing the position of the user's base station to be.  The user could then manually correct the location of the base station in the software by telling the system where the base station is actually located.  Mission planner could then use this error, and send it via telemetry to the ardupilot for a correction in the location of the rover.  

     Since the radio telemetry could easily get the current gps location from the rover, the laptop or android base station could compensate, and provide a more accurate gps reading for the rover.  

    Thanks,

    Ryan

  • Aizzat July 11, 2012 at 9:53pm

    Futhermore, if you read the datasheet from MTK GPS that was used in APM2, it capable for AGPS to get more accurate reading. 

    Link here: https://store.diydrones.com/MediaTek_MT3329_GPS_10Hz_p/mt3329-01.htm

    -Support AGPS function ( Offline mode : EPO valid up to 14 days )

     

    Is there any library that I could use to enable this AGPS function ? Do I need to add extra hardware ?

  • Aizzat July 11, 2012 at 4:25am

    Can I implement differential GPS to improve accuracy ? I read about the differential GPS in wiki, but just would like to know if this is possible with APM 2 integrated GPS module. 

  • Aizzat July 11, 2012 at 3:53am
    I need gps to give accurate reading when its on the same location. The value varies when I put at static location. I looked at gps datasheet, the acccuracy is below than 3 meter. Does it mean under 3 meter I wont get accurate reading?
  • Rick Stewart July 11, 2012 at 12:14am

    What kind of accuracy are you looking for? 

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