Tag Archives: NetCDF

GOES GRB First Light!

When the GOES-16 was first announced I got interested in their GRB Downlink (although the first try was at HRIT downlink). Basically GRB is a replacement for the old PDR downlink in GOES 13/14/15 generation, which gives few advantages over the old link:

  • Uses market standard DVB-S2 Generic Stream
  • Have FEC (as defined by DVB-S2)
  • Higher bandwidth
  • Easier to receive due DVB-S2 FEC

For those who don’t know, the GRB is a direct rebroadcast of GOES data, with minimum processing as possible (usually just packaged into NetCDF files with calibration parameters) and is intended for anyone that want’s to get full data from the satellite.

The down-link itself is split into two channels transmitted at same frequency (1684.5 MHz) with different circular polarities. That makes extremely necessary to use Circular Polarized feeds, since a Linear Feed will suffer with cross polarization (sum of each channel at the same signal).

For HRIT downlink usually a 1 meter dish is enough for receiving with a good signal (needs a very good hardware setup though). But for GRB, the minimum dish size listed by NOAA is 3.8m for the best regions.

GRB Recommended Dish Size by NOAA

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GOES 16 Test Week

Yesterday I received an email from NOAA (I’m on their “tester” list) about some tests on GOES-16 that will happen this week. Before I start talking about what will be the tests I want to be clear that GOES-16 is NOT operational yet and any data received from the LRIT/HRIT downlink are test only data. This means the user of that link assumes all risks related to the use of their data and NOAA disclaims and any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

So this week ( from 27th to 31th march ) HRIT will go into a new test phase that will send out DCS, Environmental Messages and charts through. They also will send from 16h to 20h UTC on Monday (27th) some CMI (Cloud and Moisture Imaging) data. That might be interesting for anyone that have a 1.5m+ dish that can run Linear Polarization at 1694MHz and be interested in trying out the super-alpha version of OpenSatelliteProject, that is already compatible to HRIT.

Please keep in mind that while OSP does support HRIT, it doesn’t mean it will support the new products coming out from HRIT link. They’re currently testing sending NetCDF files over HRIT, and so far OSP doesn’t support those. In normal case (no bugs) the output product should be stored in a folder named Unknown with the filename provided by NOAA. Regardless of that I will be trying to record the IQ / decoder output in the CMI period and run the OSP over all week in GOES-16.

While running in GOES-16 the Twitter / Instagram bots will not be outputing any GOES-13 data (sadly I only have one dish so far) but may output the products from GOES-16.

Some usefull links for you if you’re interested in more information: