High-resolution picture transmission

Weather satellite pictures are often broadcast as high-resolution picture transmissions (HRPTs), color high-resolution picture transmissions (CHRPTs) for Chinese weather satellite transmissions, or advanced high-resolution picture transmissions (AHRPTs) for EUMETSAT weather satellite transmissions. HRPT transmissions are available around the world and are available from both polar and geostationary weather satellites. The polar satellites rotate in orbits that allow each location on earth to be covered by the weather satellite twice per day while the geostationary satellites remain in one location at the equator taking weather images of the earth from that location over the equator. The sensor on weather satellites that picks up the data transmitted in HRPT is referred to as an Advanced Very High Resolution Radiometer (AVHRR).[1]

An HRPT Image from a NOAA Satellite

Broadcast signal
The working frequency band for HRPT is L Band at 1.670–1.710 GHz and the modulation types are BPSK and QPSK.[2] On NOAA KLM satellites the transmission power is 6.35 Watts, or 38.03 dBm.[3] The METOP-A satellite broadcasts with a bandwidth of 4.5 MHz.[4]

  • An HRPT Image from a NOAA Satellite

Reception

Hardware

In order to receive HRPT transmissions a high gain antenna is required, such as a small satellite dish, a helical antenna, or a crossed yagi. Basic reception equipment includes a parabolic dish antenna attached to an Azimuth-Elevation unit. The HRPT signal is further enhanced with a 1.7 GHz pre-amplifier. An HRPT receiver unit and a dish tracking controller are required to steer the Azimuth-Elevation unit controlling the parabolic dish. As an alternative to receiving direct broadcast from polar orbiting satellites, users in Europe and Africa can also receive rebroadcast data from the EUMETSAT EUMETCAST service via Digital Video Broadcasting using a simple stationary satellite dish.[5]

Software

Both commercial and free software for demodulating HRPT transmission signals exists: Example of commercial demodulation software is XHRPT Decoder.[6] Free software exists as a part of GNURadio package, the GR-NOAA blocks and flowcharts distributed by Manuel Bülo.[7]

Free software for decoding data packets contained in HRPT is available, for example DWDSAT HRPT Viewer V1.1.0[8] or AAPP[9] with Satpy.[10]

Satellite status
Organization Satellite Name Orbit Format Frequency Data rate
NOAA NOAA-15 Polar HRPT 1702.5 MHz 0.665Mbps[11]
NOAA NOAA-18 Polar HRPT 1707.0 MHz 0.665Mbps[11]
NOAA NOAA-19 Polar HRPT 1698.0 MHz[12] 0.665Mbps[11]
EUMETSAT Metop-A[13] Polar AHRPT 1701.3 MHz 4.66Mbps[14]
EUMETSAT Metop-B Polar AHRPT 1701.3 MHz 4.66Mbps[15]
EUMETSAT Metop-C Polar AHRPT 1701.3 MHz 4.66Mbps[16]
CMA Feng Yun FY-3A[17] Sun-synchronous AHRPT 1704.5 MHz 4.2Mbps[18]
CMA Feng Yun FY-3B[19] Sun-synchronous AHRPT 1704.5 MHz 4.2Mbps[18]
CMA Feng Yun FY-3C[20] Sun-synchronous AHRPT 1701.3 MHz 4.2Mbps[18]
RosHydroMet Meteor-M N2 Sun-synchronous AHRPT 1700.0MHz[21] 3.0Mbps[21]
RosHydroMet Meteor-M N2-2 Sun-synchronous AHRPT 1700.0MHz[22] 3.0Mbps[22]

Notes and references
  1. "Archived copy". Archived from the original on 2006-04-27. Retrieved 2009-04-12.CS1 maint: archived copy as title (link)
  2. http://www.scanex.ru/en/stations/default.asp?submenu=alice&id=specifications
  3. http://www.ncdc.noaa.gov/oa/pod-guide/ncdc/docs/klm/html/c4/sec4-1.htm
  4. "Archived copy". Archived from the original on 2008-11-26. Retrieved 2009-12-08.CS1 maint: archived copy as title (link)
  5. "EUMETCAST".
  6. "USA-Satcom xHRPT decoder setup". Retrieved 2020-01-05.
  7. "A Simple GnuRadio HRPT Decoder". Retrieved 2020-01-05.
  8. "DWDSAT HRPT Viewer - from SatSignal Software".
  9. "ATOVS and AVHRR Pre-processing Package (AAPP)".
  10. "Satpy".
  11. "NOAA table of Polar-orbiting Satellites Equator Crossing Times and Frequencies". 2011-09-01.
  12. "Archived copy". Archived from the original on 2013-07-03. Retrieved 2009-05-14.CS1 maint: archived copy as title (link)
  13. http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=pdf_td18_metop%5B%5D
  14. EUMETSAT Polar System Core Ground Segment:Metop HRPT/LRPT User Station Design Specification REF: EPS-ASPI-DS-0674 DATE: 05/03/03 ISSUE: 1.1
  15. EUMETSAT Polar System Core Ground Segment:Metop HRPT/LRPT User Station Design Specification REF: EPS-ASPI-DS-0674 DATE: 05/03/03 ISSUE: 1.1
  16. EUMETSAT Polar System Core Ground Segment:Metop HRPT/LRPT User Station Design Specification REF: EPS-ASPI-DS-0674 DATE: 05/03/03 ISSUE: 1.1
  17. "WMO OSCAR | Satellite: FY-3A".
  18. "– AHRPT on the series of FY-3 satellites is disseminated at 1704.5 MHz with a bandwidth of 6.8 MHz at a data rate of 4.2 Mbps or on Metop at 1701 MHz with a bandwidth of 4.5 MHz at a data rate of 4.66 Mbps ." Meteorological Satellite Communications David F. McGinnis, NOAA Markus Dreis, EUMETSAT 17 September 2009
  19. "WMO OSCAR | Satellite: FY-3B".
  20. "WMO OSCAR | Satellite: FY-3C".
  21. "WMO Oscar Meteor-M N2-1". Retrieved 2020-01-05.
  22. "WMO Oscar Meteor-M N2-2". Retrieved 2020-01-05.
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