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Abstract

The use of satellite navigation by aerial craft becomes more and more common. Practically every newly produced plane or helicopter has GPS receiver installed on board. This system becomes widely used because it is simple and highly reliable. To improve the Required Performance Navigation Parameters (RNP), namely, the accuracy, availability, continuity, and integrity of aircraft navigation, the integrated GPS and GLONASS techniques can be used. Users are especially interested in integrated GPS/GLONASS receivers. The appearance of new ASHTECH GG24 receiver on the market has made it possible to estimate the possibility of utilisation of this type of receivers in aircraft navigation. The main goal of performed flight trials was the use of those receivers in satellite-based approaches and landings. The authors of the report carried out an experiment aiming at data collection during flight and approach to landing of plane TS11 Iskra. The airport of Deblin was chosen as the test area. The precise trajectory of the aircraft was calculated in the global WGS'84 system of co-ordinates for subsequent positions during flight, at one-second intervals, with the use of RTK techniques in "post-processing" mode. The RTK positions were compared with DGPS/DGLONASS real-time positions and next, the estimation of real-time differential accuracy was done. The preliminary results of the accuracy analysis are given in the paper. Marek Grzegorzewski et al. AIRBORNE AND REFERENCE STATION EQUIPMENT The Airforce Academy in Dęblin has prepared TS 11 Iskra plane to this experiment, furnishing it with the following: • GG24 and Z12 receivers; • SATEL radio-modem for DGPS/DGLONASS data link; • satellite aircraft GPS/GLONASS and GPS RTK antennas. On the Navigation Department building a reference station antenna was installed (Photo 2) for GG24 receiver. Also, the base RTK Z12 receiver was set up at the point with precisely known co-ordinates in WGS'84. Photo. 1. CXL70-5C antenna of reference station Photo. 2. Ashtech aircraft antenna of GG 24 receiver at reference station Annual of Navigation 42 PRELIMINARY RESULTS OF DGPS/DGLONASS AIRCRAFT POSITIONING... The receivers were installed on board of selected TS 11 Iskra on 24 May 1999. GG24 and Z12 receivers were installed on starboard because of a good access during assembly and of disassembly and because it was easy to switch them on and off after flight. SATEL radio modems were installed in the second cabin on the external side of the ejection seat. Satellite antennas were fixed to a specially prepared rack. The distance between antennas was 10 cm. Photo. 3. The assembly of GG 24 and of Z12 receiver receivers in TS 11cockpit Fig. 1. Location of reference stations for the needs of RTK determinations