Tuesday, December 25, 2007

PLB 406Mhz

>Feb 2008 update

Personal Locater 406 MHz Beacons

Whistler SAR now has the ability to pickup PLB distress signals
Whistler SAR would be intially notified by RCC in Victoria

Development of a new generation of beacons transmitting at 406 MHz commenced at the beginning of the Cospas-Sarsat project. The 406 MHz units were designed specifically for satellite detection and Doppler location, and provide the following:

  • improved location accuracy and ambiguity resolution;
  • increased system capacity (i.e. capability to process a greater number of beacons transmitting simultaneously in field of view of satellite);
  • global coverage; and
  • unique identification of each beacon.

System performance is greatly enhanced both by the improved frequency stability of the 406 MHz units and by operation at a dedicated frequency.

These beacons transmit a 5 Watt RF burst of approximately 0.5 seconds duration every 50 seconds. The carrier frequency is very stable and is phase-modulated with a digital message. Frequency stability ensures accurate location, while the high peak power increases the probability of detection. The low duty cycle provides a multiple-access capability for a large number of beacons simultaneously operating in view of a polar orbiting satellite, and low mean power consumption.

An important feature of 406 MHz emergency beacons is the digitally encoded message, which can provide information such as the country of beacon registration and the identification of the vessel or aircraft in distress, and optionally, position data from onboard navigation equipment.

An auxiliary transmitter (homing transmitter) is usually included in the 406 MHz beacon to enable suitably-equipped SAR forces to home on the distress beacon.

To ensure that 406 MHz beacons are compatible with the Cospas-Sarsat System, detailed specifications and type approval testing standards have been adopted.

The following information is available by clicking on the appropriate hyperlink:

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