Patent ID: 7570205

Claim:
An apparatus for automatically determining a Selective Availability (SA) engine type of a Global Positioning System (GPS) receiver, the apparatus comprising: a GPS receiver configured to receive signals from at least one GPS satellite, the receiver having a SA engine configured to set at least one value based on a predefined SA engine type; and a detector configured to determine the SA type of the SA engine based on a Horizontal FIG. of Merit (HFOM) value and a Horizontal Dilution of Precision (HDOP) value received from the GPS receiver, wherein the detector comprises: a first component configured to compute an estimate of User Equivalent Range Error (UERE) based on the HFOM and the HDOP values; a second component configured to filter the UFRE estimate; and a third component configured to determine the SA engine type based on the filtered UERE, wherein the receiver and detector are mounted in an aircraft.