Weather satellite A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be polar orbiting (covering the entire Earth asynchronously), or ge ...

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). 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 Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency reference signal (the carrier wave). The modulation is accomplished by varying the sine and cosine inputs at a ...

. On

NOAA The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

KLM satellites the transmission power is 6.35 Watts, or 38.03 dBm. The

METOP-A Metop (Meteorological Operational satellite) is a series of three polar-orbiting meteorological satellites developed by the European Space Agency (ESA) and operated by the European Organisation for the Exploitation of Meteorological Satellites ...

satellite broadcasts with a bandwidth of 4.5 MHz. File:Fran10.jpg, 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 satellite dish is a dish-shaped type of parabolic antenna designed to receive or transmit information by radio waves to or from a communication satellite A communications satellite is an artificial satellite that relays and amplifies radi ...

, 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 Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) ...

using a simple stationary satellite dish.

Software

Both commercial and free software for demodulating HRPT transmission signals exists: Example of commercial

demodulation Demodulation is extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from the modulated ...

software is XHRPT Decoder. Free software exists as a part of GNURadio package, the GR-NOAA blocks and flowcharts distributed by Manuel Bülo. Free software for decoding

data packets In telecommunications and computer networking, a network packet is a formatted unit of Data (computing), data carried by a packet-switched network. A packet consists of control information and user data; the latter is also known as the ''Payload ...

contained in HRPT is available, for example DWDSAT HRPT Viewer V1.1.0 or AAPP with Satpy.

Satellite status

Notes and references

{{reflist Satellite broadcasting Weather satellites