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NMEA (GPS) data tracker

  1. Apr 25, 2014 #1

    I am making an NMEA (GPS) signal tracker. (NMEA data is sent from satellites, funcubes plus many more objects e,g, animal tracking) and will be used to aim it's antenna toward the signal for better reception. I assume that this is used for telescope aiming also.

    The data includes location. Follow the link for information: http://www.gpsinformation.org/dale/nmea.htm

    What I am hoping for is a calculation between two of these points. 1/Tracker and 2/target. Is anyone willing to help me please?

    Cheers, Camerart.
  2. jcsd
  3. Apr 25, 2014 #2


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    welcome to PF :smile:

    not directly in the aiming .... initially its more of a location of the telescope thing
    My telescope is a "GOTO" scope. It has a GPS receiver in it and the scope computer uses that data and then the manual location of several bright stars and from that info the computer can locate any object in its database that is currently above the horizon
    Pretty cool :)

    not sure how to answer that, or if I even can ? do some more clarifying please
    what 2 points ? are they both on earth? or is one of them the satellite ?

    Last edited: Apr 25, 2014
  4. Apr 25, 2014 #3
    Hi, Thanks.

    From what you say, your telescope has a GPS so that it can compare it's location with a database, for the aiming calculation.

    I think the difference in what I want is, that the second location is received through an antenna and radio receiver. I need a program to calculate the two locations, to add to a PIC program, so it can tell the two motors which way to move. Very similar to yours.

    Cheers, Camerart.
  5. Apr 25, 2014 #4


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    Yes, if you have two sets of lat/long coordinates, you can find the angle and length of a line between them with geometry. That's a basic component of navigation. Googling finds lots of online calculators for it, some that even include a cut-and-past math script to use yourself: http://www.movable-type.co.uk/scripts/latlong.html

    Now, pointing the device is not a simple problem because it isn't necessarily easy to know the starting orientation of your device. Have you put any thought into that? How accurate does the pointing need to be?
    Last edited: Apr 25, 2014
  6. Apr 25, 2014 #5
    Thanks for the link, but as you say it looks to me like two dimensional, I need three (Correct me if I've wrong)

    I'm hoping for someone, who can do the calculations, for feedback as my project moves forward.

    My device will be aimed according to either visual or previous knowledge, or in the case of animal tracking, it will be scanned around till a signal is received.

    The tracker need to be able to keep up with whatever it is tracking, some are faster than others, but the hardware will be built to cater for the calculation speed.

    Thanks, Camerart.
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