LITTON IS WORKING with Airbus Industrie to certificate by December a worldwide non-precision-approach (NPA) capability, using the global-positioning system (GPS), on the A300/A310 and A330/A340. The capability is based on integration of Litton Aero Products' LTN-2001 GPS receiver and LTN-101 Flagship laser inertial-navigation system (INS).
Litton says that its integrated GPS/INS can provide 24h, worldwide, NPA capability with GPS, using the technique of autonomous integrity-monitored extrapolation (AIME). Director of advanced programmes Vic Strachan says that AIME provides "99.999% availability" of GPS, better than achieved by receiver-autonomous integrity monitoring (RAIM).
RAIM determines whether satellite availability and geometry on approach are adequate. GPS with RAIM is now approved for supplementary use only. AIME software allows GPS/INS to be used for NPA even with only one satellite in view, according to Strachan
Flight-testing is under way and AIME is due to be certificated in mid-1995. Airbus plans to test the software on a February delivery flight to China. AIME-integrated GPS/INS capability will also be offered on the Flagship-equipped Canadair Regional Jet.
Litton is developing a GPS landing-system (GLS) based on a new, Mk3, version of its LTN-2001 receiver. This uses highly accurate "narrow-correlator"-receiver technology developed by Canadian Company Novatel. The 24-channel Mk3 will be available at the end of 1996, Strachan says.
Prototypes of the new receiver, are being supplied to Airbus and Boeing, for GLS Category III automatic-landing trials. The Airbus programme is expected to begin in February and the Boeing programme in June. In both cases, the Litton avionics will work with a Wilcox Electric local-area differential-GPS ground-station.
Source: Flight International
