Experiments On SCPC Communication And Radio Determination Using Two Geostationary Satellite

Abstract

Communications Research Laboratory (CRL) and R&D center for Radio Systems have developed a new h y b r i d satellite system which can provide both c o m m u n i c a t i o n s and p o s i t i o n i n g s e r v i c e s in o n e system using two geostationary satellites. The distinctive feature is that location information can be provided by transmitting and receiving ranging signals through two geostationary satellites over the same channel a s communications. Offset-QPSK modulation method is used to handle both communication and ranging signal through a non linear channel such as C-class HPA’s mobile terminals. A ranging signal o f 1 2 0 0 chip rate consists of a part o f PN code of 2 4 0 0 chip M-sequence. Evaluation tests performed on board a ship in the Pacific Ocean showed that positioning accuracy is about 600m at middle latitude. 1 . 0 INTRODUCTION Satellite-based radio determination systems are being developed in the world. Most systems can provide only radio determination service. I f a system w h i c h can provide both radio determination and communication service is developed, th.en we can expect various kinds o f services.Cl] Communications Research Laboratory(CRL) and R&D center for Radio systems have developed a communication and radio determination hybrid s y s t e m . W i t h a s u p p l e m e n t a r y f u n c t i o n a d d e d t o usual satellite communication systems, positioning of mobile stations and communication services such as voice and data transmission can be s i m u l t a n e o u s l y p r o v i d e d o v e r a s i n g l e c o m m u n i c a t i o n s channel.C2) This paper gives the outline o f the system and results of evaluation tests on board a s h i p in the Pacific Ocean. 2.0 E X P E R I M E N T A L SYSTEM The experimental system consists o f two geostationary satellites, ETS-V at 1 5 0 E longitude and I N M A R S A T at 180 E longitude, a base earth station (Kashima Space Research Center) and a mobile earth