From the GNSS R&D Discussion Group on LinkedIn
Hello, everyone, I am looking for a tool/software which can generate a satellite geometry distribution map of Chinese BeiDou over Asia. Just like a GPS PDOP global map. Could anyone give me a help? Thanks a lot in advance.
Maybe this tool helps you: AVIGA Service Volume Simulator: www.navpos.de/Publications/AVIGA_Pro_Flyer.pdf
We use this tool to plot satellite coverage: www.agi.com/
We have a standard mission planning tool that can do it (GPS, GLONASS, Galileo and BeiDou) and is included with our post-processing software, called EZSurv. If you’re interested to try the planner, I can send an evaluation copy of it.
You can use the (free!) Trimble online Planner (www.trimble.com/GNSSPlanningOnline/#/SatLibrary). Supports GPS, GLONASS, Galileo, BeiDou, QZSS. There was an offline tool available, too, but can’t find it anymore. Really helpful tools, thanks Trimble!
We at GMV have our own Service Volume Simulator, named polaris (www.gmv.com/en/space/Polaris/). polaris has been (and is being) extensively used in the Galileo and EGNOS programmes.
From the CANSPACE Discussion Group (ListServ)
I’d like to view broadcast SV health data that is accurate to the minute. When I use IGS stations, I can only find health data in nav files to the resolution of two hours. Could someone point me to where I could find SV health data with the granularity of 1 minute or better?
Some IGS stations stream data, including ephemerides, in real time. Presumably, any change in SV health would be reflected in an updated ephemeris. Real-time ephemeris data from the global network is provided on available Ntrip streams. Georg Weber (the scientific director in the Department of Geodesy at the German Federal Agency for Cartography and Geodesy (BKG) and a member of the IGS Real-time Working Group and the Radio Technical Commission for Maritime (RTCM) Services Special Committee (SC) 104 on Differential Global Navigation Satellite Systems (DGNSS)) kindly supplied this information:
“If I understand things correctly, then an updated navigation message is disseminated immediately when GPS operators become aware of a problem and that this is the only real-time source of information regarding SV health coming directly from the system. Hence real-time access to RTCM broadcast ephemeris messages is what you are asking for. Here is how to get it:
- Register at http://register.rtcm-ntrip.org for access to streams on Ntrip broadcaster http://products.igs-ip.net
- Download BNC from http://igs.bkg.bund.de/root_ftp/NTRIP/software/Bnc210-Windows.msi
- Pull stream RTCM3EPH for a few seconds and convert its contents to RINEX2 or RINEX3 navigation files.
- Stream RTCM3EPH contains only broadcast ephemeris for GPS and GLONASS as received from the global real-time IGS network — no observations. The broadcast ephemeris repetition/update rate is 5 seconds.”
The Navigation message is only updated every two hours (currently) so the granularity you require is not possible, as the health flag is an official designation from the GPS control center. The fastest changing navigation files are in the IGS Data centers called “hourDDD0.13n” for example, for today here: ftp://cddis.nasa.gov/gps/data/hourly/2013/318/hour3180.13n.Z
This file gets updated hourly (or more) with the contributions from the navigation files of the IGS network.
A faster way of noting changes would be to monitor several worldwide data real-time streams from public stations using the BNC software to monitor the health flags, but while the data will come in real-time the changes in flag status only take place every two hours, but at least you will see a health flag change very quickly. Check out:
I hope that is helpful.