High-resolution picture transmission
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Live 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 generally available around the world and are currently transmitted from some polar orbiting weather satellites.
Broadcast signal
The working frequency band for HRPT is L Band at 1.670–1.710 GHz and the modulation
type is BPSK.[1] On NOAA KLM satellites the transmission power is 6.35 Watts, or 38.03 dBm.[2] The METEOR-M series of satellites uses a similar format to HRPT with the same modulation.[3] The METOP satellites broadcast with a bandwidth of 4.5 MHz, these use QPSK and AHRPT.[4]
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 SatDump,[8] DWDSAT HRPT Viewer V1.1.0[9] or AAPP[10] with Satpy.[11]
Satellite status
| Organization | Satellite Name | Orbit | Service | Frequency | Data rate | Status |
|---|---|---|---|---|---|---|
| NOAA | NOAA-15 | Polar | HRPT | 1702.5 MHz | 0.665Mbps[12] | Offline |
| NOAA | NOAA-18 | Polar | HRPT | 1707.0 MHz | 0.665Mbps[12] | Offline |
| NOAA | NOAA-19 | Polar | HRPT | 1698.0 MHz[13] | 0.665Mbps[12] | Offline |
| EUMETSAT | Metop-A[14] | Polar | AHRPT | 1701.3 MHz | 4.66Mbps[15] | Offline |
| EUMETSAT | Metop-B | Polar | AHRPT | 1701.3 MHz | 4.66Mbps[15] | Transmitting |
| EUMETSAT | Metop-C | Polar | AHRPT | 1701.3 MHz | 4.66Mbps[15] | Transmitting |
| CMA | Fengyun 3A[16] | Sun-synchronous | AHRPT | 1704.5 MHz | 4.2Mbps[17] | Offline |
| CMA | Fengyun 3B[18] | Sun-synchronous | AHRPT | 1704.5 MHz | 4.2Mbps[17] | Offline |
| CMA | Fengyun 3C[19] | Sun-synchronous | AHRPT | 1701.3 MHz | 4.2Mbps[17] | Offline |
| RosHydroMet | Meteor-M N2-1 | Sun-synchronous | HRPT | 1700.0 MHz[20] | 0.6654Mbps[21] | Offline |
| RosHydroMet | Meteor-M N2-2 | Sun-synchronous | HRPT | 1700.0 MHz[22] | 0.6654Mbps[21] | Offline |
| RosHydroMet | Meteor-M N2-3 | Sun-synchronous | HRPT | 1700.0 MHz[23] | 0.6654Mbps[21] | Transmitting |
| RosHydroMet | Meteor-M N2-4 | Sun-synchronous | HRPT | 1700.0 MHz[24] | 0.6654Mbps[21] | Transmitting |