SCAT-1 Flight Testing - The Australia Experiencen

William S. Ely, Keith W. McPherson, Graeme K. Crosby

Abstract:	In July 1996, the Airservices Australia Global Navigation Satellite Systems Program Office (GNSSPO) commenced work on an Augmentation Systems Test Bed (ASTB) project. The scope of this project included the installation and testing of both local and wide area augmentation system (LAAS/WAAS) research facilities. Test results from the ASTB are planned to be used by Australian aviation authorities to develop a long term strategy for a movement towards a satellite based navigation system by the year 2010. Through a combination of collaborative research and commercial arrangements, the GNSSPO participated in the installation of three temporary SCAT-1 facilities in Australia. Two of these were Honeywell/Pelorus SLS-2000 facilities, and the other was a Raytheon DIAS-3100N facility. Airborne flight test equipment was installed in a Fokker F-28 aircraft for the first Honeywell/Pelorus system, and a Turbo-Commander G1000 aircraft for the second Honeywell/Pelorus and Raytheon systems. During the ASTB project, GNSSPO engineers (Bill Ely and Graeme Crosby) were also trained to conduct maintenance of the two SCAT-1 equipment types. In late 1998, the Government of Norfolk Island procured a Honeywell-Pelorus SLS-2000 SCAT-1 system to be used as an operational landing system. The GNSSPO has assisted with project co-ordination and initial flight validation of the system. Flight trials were conducted utilising a GPS based “Truth System” composed of two dual frequency Ashtech Z-12 GPS receivers, with position data being post-processed using Ashtech PNAV software. A total of 152 approaches were flown against the Honeywell/Pelorus systems, and a further 41 against the Raytheon system. Flight profiles were devised to assess the navigation system error (NSE) and flight technical error (FTE) of both systems, as well as providing information on the flight inspection requirements for the commissioning and maintenance of LAAS systems, both SCAT-1 and the future public use CAT-1 systems. To date, quantified analysis of the data has focussed on assessing the NSE, with later work planned to formally assess FTE. Results from the flight trials indicate that both systems would have met the current FAA SCAT-1 commissioning standards (FAA Order 8200.41) for accuracy, and provided an insight into the potential improvements in system performance when compared to current ILS technology. Initial indications are that some refinement of the Category 1 instrument approach design standards may be possible due to the low values of NSE experienced, with FTE being more likely to limit instrument approach design standards. The Australian experience has provided confidence in LAAS technology as a viable component of a satellite based navigation system. It has also provided an extensive experience base on which to build standards for equipment installation; maintenance and certification; instrument approach design; pilot licensing and training; and operational approvals.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	651 - 662
Cite this article:	Ely, William S., McPherson, Keith W., Crosby, Graeme K., "SCAT-1 Flight Testing - The Australia Experiencen," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 651-662.
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