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Differential GPS Server

This tutorial describes how to connect to the University of Bristol's Differential GPS Server. The server serves raw GPS correction data (RTCM SC-104) to all clients connected to it. The data is intended for direct relay to a GPS device such as the Garmin modules on the jackets.

How Does it Work?

The server application runs on a machine (Pele) in the wearable computing lab. It receives dGPS correction data serially from a dGPS beacon receiver unit (CSI SBX-3) with an aerial on the roof of the Merchant Venturer's building. The strongest beacon received here is from a transmitter at Nash Point (station ID: 0689) near Cardiff. Clients connecting to the server receive the data from this unit in its raw form.

Connecting to the Server

  1. Open a TCP socket to port 2101 (IANA assigned) on Pele - 192.168.105.3.
  2. Read from the socket and send the binary data directly to the GPS device. There is no protocol involved - the server will immediately begin sending data to the socket upon connection.
  3. Close the socket when dGPS data it is no longer required.

Code for the client that runs on the Bitsies is freely available. Ask a member of the wearable staff for access to it.

The dGPS server is based on a service set up by Wolfgang Rupprecht of WSRCC in Fremont, California. For more information see his website dedicated to dGPS over IP.


This page last updated July 11, 2002
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