How to build my own DGPS


I'm trying to build an autonomous Qudrotor that will use DGPS to get accurate possition.

I'm using the "Mikrokoper" body and the Gluonpilot controller.

I have two "Trimble Lassen IQ" GPS receivers. I've find out that those cards are capable of outputting the raw data  and can get RTCM SC-104.

Actually I don't know where to start to I'll start with a few quastions:


1) If the GPS receiver can get RTCM SC-104 signals, does it means that if I will create such signal using the raw data from the base station, the rover's card would do the correction by himself?


2) How can I create RTCM correction message from the base station raw data? Is it possible to do it?


3) In case that the above steps are too complicate to achieve, what kind of GPS receivers are

recommending to  build a DGPS?  What kind of communication is recommending to  transmit the GPS data from the base station to the rover? (XBee will work?)





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  • Hey friend, i am little confuse about this question but i think i have some solutions to share, we can see at this website may be it's helpful, what i find is, we can make our own radio station and from here we can radio stations with using advance technology. I hope it will solve your and many people who wants to find this types of information's.

    • HEllo lokendra kharel ji. 

      Ma tapai sanga k hi kura garnu thiyo DGps ko barema?? ma tapailai personally kasari kura garna sakchu. 

      my email 

  • Hi Lior,

    Hope you have solved Trimble iQ lassen raw data output.
    I started programming it but no success at moment.

    take a look on this thread:



  • Also, take a look at RTKLib ( which is a library for computing precision (<1 cm) position solutions from raw data received from more than one GPS receiver.

    Hope this helps,


    RTKLIB: An Open Source Program Package for GNSS Positioning
  • I had previously commented on Tom Kent's page to the effect that some amateur radio folks put together a DGPS reference station a while back using Motorola Oncore GPS, which the UT+ model supported "site survey" mode. A survey took about 3 hours but then you had your own reference.
    You can still find the HW docs here:
    and the DGPS C (RTCM) code here:   Control software with site survey mode is here:
    You can also find these old GPS units on ebay, you are probably better off with something newer.  I plan to use Ublox LEA-6T-0 (precision timing, 5Hz,raw data available for RTCM) for the base station, and probably LEA-6S or -6A for the rover.

    • Hi Darryl,

      I realise you posted this a long time ago but it's relevant to what I'm doing now. I recently acquired a LEA6T-0 chip (with the evaluation kit) and have managed to get coordinates to within 40cm of reference points with post processing of regional correction data available in my country. 

      How did you get on with yours? Did you ever get into real time corrections going? I'm interested in using this chip as a base to generate my own on-site correction data, and feed that wirelessly to my UAV. 



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