So far you have confirmed that your distress beacon will be used as an aviation Emergency Locator Transmitter (ELT) and that it is a location protocol beacon. Three coding options have been developed for this type of beacon. However, your selection should be restricted to those protocols that have been authorised by your country’s competent authority on distress beacon matters (additional information concerning the authority/responsibility of States in respect of beacon message protocol selection is described at step 1 of this tutorial).
It should also be noted that the beacon message protocols that have been verified during the type-approval testing are shown on the Cospas-Sarsat Type Approval Certificate issued by the Cospas-Sarsat Secretariat.
In view of the above, the selection of protocol should be further limited to those that have been type approved for use with the beacon model selected.
Having satisfied the two overriding criteria detailed above, the coding option to be selected depends on the information that you would like programmed into the beacon and its intended use. To proceed, select the option that best suits your needs.
User Location Protocols: This option is formed by coding bits 1 through 106 of the ELT as a User Protocol, and providing the encoded location information to 4-minute resolution (approximately 6 miles or 10 kilometers) in the remaining bits. These protocols are only available in the long message format, and provide the lowest accuracy resolution of all long message format location protocols.
Standard Location Protocols: This option uniquely identifies the ELT using either:
- the 24-bit binary aircraft identification assigned by National Administrations,
- a unique serial number allocated by either the competent national authority or the beacon manufacturer accompanied by the Cospas-Sarsat beacon type approval certificate number, or
- the Aircraft Operator designator and a serial number.
The Standard Location Protocols allow for location information of 4-second resolution to be encoded in the beacon message (approximately 120 meters). These protocols are only available in the long message format.
National Location Protocols: This option uses a unique serial number allocated by the competent national authority to uniquely identify the beacon. The National Location Protocols allow for location information of 4-second resolution to be encoded in the beacon message (approximately 120 meters). These protocols are only available in the long message format.