high-resolution picture transmission
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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) for NOAA satellites.{{Cite web |url=http://noaasis.noaa.gov/NOAASIS/ml/avhrr.html|title=NOAASIS - NOAA Satellite Information System for NOAA Meteorological / Weather Satellites |access-date=2009-04-12 |archive-url=https://web.archive.org/web/20060427201736/http://noaasis.noaa.gov/NOAASIS/ml/avhrr.html |archive-date=2006-04-27 |url-status=dead }}
Broadcast signal
The working frequency band for HRPT is L Band at 1.670–1.710 GHz and the modulation
type isBPSK.http://www.scanex.ru/en/stations/default.asp?submenu=alice&id=specifications On NOAA KLM satellites the transmission power is 6.35 Watts, or 38.03 dBm.{{Cite web |url=http://www.ncdc.noaa.gov/oa/pod-guide/ncdc/docs/klm/html/c4/sec4-1.htm |title=NOAA KLM USer's GUIDE Section 4.1 |access-date=2009-12-08 |archive-date=2010-05-27 |archive-url=https://web.archive.org/web/20100527194915/http://www.ncdc.noaa.gov/oa/pod-guide/ncdc/docs/klm/html/c4/sec4-1.htm |url-status=dead }} The METOP-A satellite broadcasts with a bandwidth of 4.5 MHz, these use QPSK and AHRPT.{{cite web |url=http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=PDF_ASPI_0674_EPS_CGS-US-SP&RevisionSelectionMethod=LatestReleased |title=Archived copy |accessdate=2009-12-08 |url-status=dead |archiveurl=https://web.archive.org/web/20081126153454/http://www.eumetsat.int/idcplg?IdcService=GET_FILE&dDocName=pdf_aspi_0674_eps_cgs-us-sp&RevisionSelectionMethod=LatestReleased |archivedate=2008-11-26 }}
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.{{cite web|url=https://www.eumetsat.int/eumetcast|title=EUMETCAST|date=5 May 2020 }}
= Software =
Both commercial and free software for demodulating HRPT transmission signals exists: Example of commercial demodulation software is XHRPT Decoder.{{Cite web|url=https://uhf-satcom.com/blog/usa-satcom-xhrpt-decoder-setup|title=USA-Satcom xHRPT decoder setup|last=|first=|date=|website=|archive-url=|archive-date=|access-date=2020-01-05}} Free software exists as a part of GNURadio package, the GR-NOAA blocks and flowcharts distributed by Manuel Bülo.{{Cite web|url=https://tynet.eu/hrpt/hrpt-decoder|title=A Simple GnuRadio HRPT Decoder|last=|first=|date=|website=|archive-url=|archive-date=|access-date=2020-01-05}}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
Free software for decoding data packets contained in HRPT is available, for example DWDSAT HRPT Viewer V1.1.0{{Cite web | url=http://www.satsignal.eu/software/dwd-hrpt.htm | title=DWDSAT HRPT Viewer - from SatSignal Software}} or AAPP{{Cite web|url=https://www.nwpsaf.eu/site/software/aapp/|title=ATOVS and AVHRR Pre-processing Package (AAPP)}} with Satpy.{{Cite web|url=https://satpy.readthedocs.io/|title=Satpy}}
Satellite status
| class="wikitable" |
| Organization
! Satellite Name ! Orbit ! Service ! Frequency !Data rate !Status |
|---|
| NOAA
| NOAA-15 | Polar | HRPT | 1702.5 MHz |Transmitting |
| NOAA
| NOAA-18 | Polar | HRPT | 1707.0 MHz |Offline |
| NOAA
| NOAA-19 | Polar | HRPT |Transmitting |
| EUMETSAT
| Polar | AHRPT | 1701.3 MHz |4.66MbpsEUMETSAT Polar System Core Ground Segment:Metop HRPT/LRPT User Station Design Specification REF: EPS-ASPI-DS-0674 DATE: 05/03/03 ISSUE: 1.1 |Offline |
| EUMETSAT
| Metop-B | Polar | AHRPT | 1701.3 MHz |Transmitting |
| EUMETSAT
| Metop-C | Polar | AHRPT | 1701.3 MHz |Transmitting |
| CMA
| Fengyun 3A{{Cite web | url=http://www.wmo-sat.info/oscar/satellites/view/113 |title = WMO OSCAR | Satellite: FY-3A}} | AHRPT | 1704.5 MHz Meteorological Satellite Communications David F. McGinnis, NOAA Markus Dreis, EUMETSAT 17 September 2009 |Offline |
| CMA
| Fengyun 3B{{Cite web | url=http://www.wmo-sat.info/oscar/satellites/view/114 |title = WMO OSCAR | Satellite: FY-3B}} | Sun-synchronous | AHRPT | 1704.5 MHz |Offline |
| CMA
| Fengyun 3C{{Cite web | url=http://www.wmo-sat.info/oscar/satellites/view/115 |title = WMO OSCAR | Satellite: FY-3C}} | Sun-synchronous | AHRPT | 1701.3 MHz |Transmitting |
| RosHydroMet
|Meteor-M N2 |Sun-synchronous |AHRPT |Offline |
| RosHydroMet
|Meteor-M N2-2 |Sun-synchronous |AHRPT |Offline |
| RosHydroMet
|Meteor-M N2-3 |Sun-synchronous |AHRPT |Transmitting |
| RosHydroMet
|Meteor-M N2-4 |Sun-synchronous |AHRPT |Transmitting |