Mitglieder der Amaterufunkforschungsgruppe haben das erstes freie Programm zur Decodierung von Graw Wettersonden veröffentlicht. Diese Wettersonden werden beispielweise von der Bundeswehr in Baumholder genutzt. Unsere Software wurde ins Programm SondeMonitor integriert.

Projektbeschreibung:

Accurate weather prediction models such as the Global Forecast System are depending on exact atmospheric data [1]. For this purpose, radio probes are used worldwide for measuring the pressure, temperature, humidity and wind up to a height of 40 km [2]. For few of these probes the code of the transmission is known[3], while there is a program for the decoding of the Vaisala RS80, RS92SGP and RS92AGP [4]. In this work we extract the GPS-coordinates from the audio signal of a FM-receiver and analysed the coding scheme.

The radio probe DFM-06 is a fully digitalized radio probe from the German company GRAW [5]. This instrument is designed for measuring the temperature and humidity in earth’s atmosphere up to 40 km. The included GPS-module from Navman Wireless OEM Solutions uses a SIRFstar II chipset [6]. The position error is less than 10 m and the error in velocity is less than 0 .1 ms. To increase the accuracy the usage of DGPS is possible, SBAS-data is transmitted together with the position-data [7]. Many interesting experiments with the radio probe and its GPS-module are conceivable. Therefore the Manchester-coded signals have to be decoded. We took a look at the different coding layers and demonstrated a way to extract the GPS coordinates from the data.

Results: The coding scheme of the DFM-06 was found, by analysing the signals sent by a DFM-06 radio probe. Some of the data, e.g. the GPS location of the probe was identified in the signal, but there are still some parts e.g. the temperature and the humidity data, as well as the SBAS signal to be found. A complete understanding of the code will render a multitude of experiments possible and may allow ham-radio weather balloons with special test licenses for the weather band or by mixing the HF signal to a ham-radio band.

Downloads:

Here you can download a software decoder for the Graw DFM-06 Radiosondes developed by members of our research group:
radiosonde_decoder_0.3.tar.gz

Here are some precompiled binaries:
i386_linux.tar.gz
i386_win32.tar.gz

Here you can find jSonde, an easy to use Java-based software from Michael Becker:
https://sourceforge.net/projects/jsonde/files/

[1] NOAA National Weather Service. National centers for environmental prediction,
July 2011. URL www.emc.ncep.noaa.gov/GFS/.
[2] Instituts für Geophysik und Meteorologie Uni Köln. Radiosondenaufstiege der welt,
July 2011. URL
www.uni-koeln.de/math-nat-fak/geomet/meteo/winfos/radiosonden/index erde.html.
[3] Ch. Häberli. Ptu am beispiel von vaisala’s digicora und marwin, Dec. 2001. URL zft.de/decoder/convert.pdf.
[4] Centro de Observacao Astronomica no Algarve. Sondemonitor 5.5.3, July 2011. URL www.coaa.co.uk/sondemonitor.htm.
[5] GRAW Radiosondes GmbH & Co. KG. URL www.radiosondes.com.
[6] Navman Wireless OEM Solutions. Jupiter 30 xlp datasheet, July 2009. URL www.navmanwirelessoem.com/Jupiter-30-xLP.html.
[7] GRAW Radiosondes GmbH & Co. KG. Dfm-06 data sheet version 01.00, May 2010.