Differential GPS is right approach, US tests prove
Raytheon has demonstrated differential global positioning system (DGPS) precision approaches performed by a civil aircraft using the manufacturer's ground station originally developed for the military.
The demonstrations come ahead of the US Federal Aviation Administration's final request for offers for a Category I local area augmentation system (LAAS), for which Raytheon is competing against Honeywell and Thales ATM-led consortia.
The demonstrations were performed by a FedEx Express Boeing 727-200 equipped with a Rockwell Collins GNLU-930 multi-mode receiver. Sixteen Category I approaches were performed at Holloman air force base using a Raytheon ground station being developed under a US Air Force contract for the Joint Precision Approach and Landings System programme to provide an anti-jam, secure, all-weather Category II/III landing system.
During the tests, the FedEx 727-200 conducted a number of pilot flown approaches for reference followed by six full autolands with DGPS corrections, integrity information and precision approach path points transmitted by the ground station. The approaches were restricted to Cat I, but the trials demonstrated accuracies sufficient to meet Cat II/III requirements, says the manufacturer.
The LAAS contract is due to be awarded in April. LAAS will augment the wide area augmentation system, providing all-weather approach and landing capability.
Source: Flight International
