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GPS vs. Compass Module for direction — Parallax Forums

GPS vs. Compass Module for direction

EmilyPEmilyP Posts: 21
edited 2010-09-13 14:22 in Accessories
Hello,

If someone could help me with this one that would be great.· Does anyone know how any of the GPS modules compare with the compass module that I have been using as far as accuracy goes?· It is http://www.parallax.com/Store/Sensors/CompassGPS/tabid/173/ProductID/98/List/1/Default.aspx?SortField=ProductName,ProductName

At first glance, the compass is better for indoors but it's only as good as your calibration.· But, in an outdoor setting, I would assume the GPS is more accurate for direction.· Can anyone verify this?

Thanks ahead!

Emily ·

Comments

  • TimmooreTimmoore Posts: 1,031
    edited 2009-07-06 21:37
    GPS can't tell direction if stopped, it works out direction by change in position.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-07-06 23:43
    GPS can also report an incorrect heading while stationary due to variances in each reading.· Higher end commercial GPS units have dedicated compass and sometimes altimeter.

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    Chris Savage
    Parallax Engineering
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-09-13 08:09
    The new search engine turned up this post and it answer half of my question. Since the GPS can only tell direction when it is moving it appears that I will also need to add a compass module to my robot in addition to the GPS.

    There is one other question I still have about the GPS module. Is there any recommendations for mounting? I had assumed that that antenna should be up but wasn't sure if there was a "front" of the sensor that should be facing forward (the normal direction of travel) which I would be concerned about using a compass. Since there isn't a compass module I suppose mounting isn't a issue.

    Robert
  • LarryGLarryG Posts: 50
    edited 2010-09-13 12:42
    You might check out the Locosys LS20126. It has a built in compass module as well as GPS. It substitutes the heading from the compass at low speeds. Sparkfun has them
    http://www.sparkfun.com/commerce/product_info.php?products_id=9838
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-09-13 14:22
    Thanks for the link. That may be something to look at for future projects. Since I already have the Parallax GPS Receiver Module # 28146 I think I'll just try adding a compass module for the heading.

    Robert
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