Bernard Fitzsimons/EDINBURGH
The UK National Air Traffic Services (NATS) is working with avionics manufacturer Rockwell Collins to build on its recently demonstrated ability to provide accurate automatic guidance to aircraft during all phases of flight using global navigation satellite system (GNSS) positioning data.
Early this month a BAC One-Eleven operated by the UK's Defence Evaluation and Research Agency (DERA) demonstrated the capability in Scotland, following a series of validation flights at DERA's Boscombe Down airfield in February. They included area navigation (RNAV) operations as well as straight-in and curved approaches at glideslope angles of up to 7.5°. The GNSS guidance was used to fly the aircraft automatically from take-off to final approach.
The flight trials were intended to explore the potential of GNSS as a cost-effective enabler for RNAV, NATS Infrastructure Services senior systems engineer Steven Leighton said at the GNSS 2000 conference, which took place in Edinburgh, Scotland, earlier this month. RNAV capability provides greater flexibility in route planning, a reduction in air traffic controller workload by reducing the need to provide radar vectors and more fuel-efficient routes for operators. The One-Eleven trials should also be useful for validating the European Geostationary Navigation Overlay System (EGNOS), the first phase of Europe's GNSS programme which is due for implementation in 2003.
The space-based augmentation (SBAS) demonstration platform consisted of a NovAtel Millennium global positioning system (GPS) receiver modified to receive signals generated by the EGNOS testbed at London Gatwick Airport and relayed via Inmarsat satellite.
The SBAS platform outputs aircraft position, SBAS glidescope and SBAS localiser guidance to the One-Eleven's experimental flight management system (EFMS). The EFMS outputs the glidescope to the autopilot and gives lateral RNAV guidance until the straight-in segment, when the autopilot is coupled directly to the SBAS platform. Coupled go-around guidance should be completed by the end of this year.
Source: Flight International
