6.1.4 Beacon Location Accuracy
The accuracy of the beacon location that is provided by the Cospas-Sarsat System must be within 20 km or less of the true location of the beacon, as required by the Cospas-Sarsat specifications. However, as noted below, the locations produced by the System are normally significantly more accurate than that.
The location accuracy of the position information that is encoded in the beacon message is based on the accuracy of the underlying GNSS or navigation system that produces this location data If a beacon has an internal GNSS chip, the encoded location data can be within one hundred metres of the true beacon position.
The Doppler solutions that are produced by the LEOLUTs are normally (more than 95% of the time) accurate to better than five kilometres of the true beacon location.
Although this is still being demonstrated, the DOA solutions that are produced by the MEOLUTs for Second Generation Beacons (SGBs) are expected to be accurate, on a single transmission, to less than five kilometres from the true beacon location. After several transmissions, this accuracy significantly improves; the fully operational MEOSAR system processing data from SGBs is expected to achieve one hundred metre accuracy within ten minutes after the first transmission.
The accuracies quoted above are illustrated in the images in Figure 6‑1.
Figure 6‑1: Cospas-Sarsat Solution Accuracy
This illustration shows the accuracy that is specified for the locations
generated
by the various sub-systems of the Cospas-Sarsat System.