Decoding Differential GPS (DGPS) with an RSPdx and MultiPSK
Over on YouTube the TechMinds channel has uploaded a new video about decoding Differential GPS (DGPS) using an SDRplay RSPdx SDR. DGPS is a terrestrially transmitted long wave signal that is used to help correct and improve GPS position data calculations which may have timing errors due to atmospheric propagation delays. It works by broadcasting correction data calculated by the difference in received GPS location and the known location of the DGPS transmission site. DGPS is typically transmitted on longwave between 285 kHz and 315 kHz, but in Argentina there are two stations at 2570 and 2950 kHz.
In the video TechMinds explains how DGPS works, and some location around the world from where it is transmitted from. Later in the video he shows a DGPS signal being received by a SDRplay RSPdx SDR, and then show a demo of how it can be decoded with MultiPSK.
We note that there also various other DGPS decoders available including decoders for Android and iOS. A list of decoders can be found on the DGPS sigidwiki page.
The Techmind video explains DGPS excellently. For those who don’t own a SDR, you can use any radio that covers the longwave band and has a BFO for SSB reception. In my area of the USA (NE coast) DGPS beacons are heard nightly, especially in winter, with some signals heard as far as the Midwest and can be used for determining band conditions. MultiPSK is excellent programming software for decoding DGPS. Thanks for posting the video.