System Design and Flight Experiment Results of the Pseudolite DGPS System for Automatic Landing Flight Experiment (ALFLEX)

Shuichi Matsumoto, Hideto Suzuki and Tatsushi Izumi, Masatoshi Harigae, Toshiaki Tujii, Kazntoshi Ishikawa and Takatsugu One, Atsushi Itsukaichi, Hiroaki Maeda, Hiroshi Tomita and Tomoyuki Miyano

Abstract:	National Space Development Agency of JAPAN (NASDA) and National Aerospace Laboratory (NAL) have been studying the Japanese umnanned winged space vehicle named HOPE, and carrying out various experiments to establish key technologies for HOPE. In order to establish automatic landing technologies for HOPE, Automatic Landing Flight Experiment (ALFLEX) was carried out from July to August in 1996. And as one of the research items of the ALFLEX, we designed and mamifactured the pseudolite DGPS system for ALFLEX, and evahrated its function and performance by the ground experiment and by the flight experiment. We chose the pseudolite method for the DGPS system for ALFLEX, which consists of the pseudolite ground station and the onboard DGPS receiver (DGPSR). Main reasons of this choice are the simplification of the onboard system and the improvement of the geometrical dilution of precision (GDOP) at landing. For a space plane such as HOPE, it is important to simpliQ the onboard system and to lighten its weight. Also, it is important to improve GDOP because a space plane must use a heat-resistant antenna whose antemra gain for low elevation angle is not good. On the other hand, the pseudolite method has some technical problems such as the radio interference problem and the near-far problem. We designed the pseudolite DGPS system without these problems. The ground experiment was carried out to verify the function of the system and to confirm that the pseudolite signal does not interfere with the non-target GPS receivers which are more than 1OOm apart from the pseudolite ground station. The airplane flight experiment was carried out at Sendai airport to evaluate the performance of the system. After these experiment, this system installed to the ALFLEX system and used for the automatic landing flight experiment at Woomera airfield, Australia. This paper presents the system design results of the pseudolite DGPS system for ALFLEX; the DGPS algorithm, the pseudolite ground station, and the DGPS receiver. This paper also presents the results of the ground experiment and the flight experiment.
Published in:	Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996) September 17 - 20, 1996 Kansas City, MO
Pages:	87 - 94
Cite this article:	Matsumoto, Shuichi, Suzuki, Hideto, Izumi, Tatsushi, Harigae, Masatoshi, Tujii, Toshiaki, Ishikawa, Kazntoshi, One, Takatsugu, Itsukaichi, Atsushi, Maeda, Hiroaki, Tomita, Hiroshi, Miyano, Tomoyuki, "System Design and Flight Experiment Results of the Pseudolite DGPS System for Automatic Landing Flight Experiment (ALFLEX)," Proceedings of the 9th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1996), Kansas City, MO, September 1996, pp. 87-94.
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