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SARRSearch and Rescue Repeater (SARR) SARPSearch and Rescue Processor (SARP) Receiver Power Unit (RPU) and SARP Signal Processing Unit (SPU)

Search and Rescue Repeater and Processer (SARR and SARP)

The Search and Rescue instruments are part of the international Cospas-Sarsat system designed to detect and locate Emergency Locator Transmitters (ELTs), Emergency Position-Indicating Radio Beacons (EPIRBs), and Personal Locator Beacons (PLBs) operating at 121.5, 243, and 406.05 MHz. The NOAA spacecraft carries two instruments to detect these emergency beacons: the Search and Rescue Repeater (SARR) provided by Canada and the Search and Rescue Processor (SARP-2) provided by France. Similar instruments are carried by the Russian COSPAS polar-orbiting satellites.

The SARR transponds the signals of 121.5, 243, and 406.05-MHz emergency beacons. However, these beacon signals are detected on the ground only when the satellite is in view of a ground station known as a Local User Terminal (LUT). The SARP detects the signal only from 406.05-MHz beacons but stores the information for subsequent downlink to a LUT. Thus, global detection of 406.05-MHz emergency beacons is provided. This processor consists of a receiver power unit (rpu) and signal processing unit (spu).

The U.S. fishing fleet is required to carry 406.05-MHz emergency beacons. The 406.05-MHz beacons are also carried on most large international ships, some aircraft, and pleasure vessels, as well as on terrestrial carriers. The 121.5-MHz and 243-MHz beacons are required on many small aircraft with a smaller number carried on maritime vessels.


SARSAT Subsystem Characteristics


Search and Rescue Repeater (SARR) Bandwidths
(Doppler shift + drift + Tolerance + guardband)

Parameter
Specification
121.5 MHz
25 kHz
243 MHz
46 kHz
406.050 MHz
100 kHz
Transmitter Power (1,54 MHz)
8 W decibels referenced to a watt (dBW)

Physical Characteristics
(receiver power unit)

Parameter
Specification
Weight
24 kg
Size
0.034 m3
Power
53 W

Search and Rescue Processor (SARP)
(signal processing unit)

Parameter
Specification
Maximum Bandwidth
80 kHz
Storage Capacity
324 kb
Output Data Rate (via Telemetry)
2.4 kbps

Physical Characteristics

Parameter
Specification
Weight
27.5 kg
Size
0.034 m3
Power
33 W
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