Low Rate Picture Transmission (LRPT)

Weather Satellite Modes: APT - LRPT - Meteosat WEFAX

Low Rate Picture Transmission (LRPT)

Frequencies	137 MHz,138 MHz
Frequency Range	137 MHz - 138 MHz
Mode	RAW
Modulation	QPSK
ACF	0.5 ms
Emission Designator	—
Bandwidth	120 kHz
Location	Worldwide
Short Description	The Low Rate Picture Transmission (LRPT) is a digital transmission system, commonly transmitted by METEOR-M satellites, used to deliver weather images and data.
I/Q Raw Recording	Download file
Audio Sample	—

The Low Rate Picture Transmission (LRPT) is a digital transmission system, intended to deliver images and data from an orbital weather satellite directly to end users via a VHFVery High Frequency (30-300 MHz) radio signal. It is used aboard polar-orbiting, near-Earth weather satellite programs such as MetOp (LRPT permanently deactivated on MetOp-A due to interference with on HIRS) and NPOESS (replaced with JPSS), and is currently being used on METEOR-M satellites.

Characteristics

LRPT transmits at ~120 kHzKiloHertz (kHz) 10^3 Hz Bandwidth. The signal transmits using QPSKQuadrature Phase-Shift Keying (2 bits per symbol) at 72 kBdkilobaud, kilosymbols per second (ksym/s) (72,000 symbols per second) with a raw data rate of 144 kbpsKilobits per second (kbps). The datastream is processed using a Reed–Solomon error correction, then convolution encoded, interleaved, and padded with unique synchronization words.

The bandwidth is sufficient for 3 channels from the MSU-MR radiometer. Any of the six channels provided by the radiometer can be selected to be transmitted in the LRPT data stream.

Frequencies

• Meteor-M N2-2 137.1 MHzMegaHertz (MHz) 10^6 Hz - 137.9125 MHzMegaHertz (MHz) 10^6 Hz (No LRPT broadcast, but the HRPT broadcast is working)
• Meteor-M N2-3 137.1 MHzMegaHertz (MHz) 10^6 Hz - 137.9125 MHzMegaHertz (MHz) 10^6 Hz (Active, antenna not deployed correctly)
• Meteor-M N2-4 137.9 MHzMegaHertz (MHz) 10^6 Hz (137.1 MHzMegaHertz (MHz) 10^6 Hz used as a backup frequency) (Active)

Decoding Tutorials

• Guide on how to easily decode LRPT broadcasts from the METEOR satellites

Video Examples

• Live Decoding Meteor-M N2 plugin QPSK and LRPTonLineDecoder
• Receiving and Decoding Meteor M2 Weather Satellite
• High Detail Weather Images from Russian Meteor M2 Satellite Using SDR
• Jak to działa. Meteor-M N2 odbiór zdjęć stelitarnych za pomocą SDRSharp'a (TUTORIAL).
• IZ5RZR - How to receive Meteor M2 Satellite
• IZ5RZR - decode METEOR M2 satellite in realtime
• - Grabbing Images From New Russian Satellite (Meteor M2-3)

Additional Links

• Wikipedia Low-Rate Picture Transmission
• Wikipedia METEOR satellites
• Meteor-M satellite operational status

Additional Images

LRPT Signal from the Meteor-M N2 Satellite at 137 MHzMegaHertz (MHz) 10^6 Hz. Example of an image received from a Meteor-M N2 satellite transmitting on LRPT. Spectrum Analysis of LRPT Signal Here we see clearly that there is a strong correlation when x^n is set to n=4, which shows that this signal is QPSKQuadrature Phase-Shift Keying (2 bits per symbol) (4PSKQuadrature Phase-Shift Keying (2 bits per symbol)) Phase plane of LRPT's QPSKQuadrature Phase-Shift Keying (2 bits per symbol) phase view.