1991 Volume 1991 Issue 67 Pages 79-94
In order to develop satellite communication and ranging techniques for aircraft and ships in the oceanic area, ENRI started navigation experiment using ETS-V in November 1987. Ship experiments with medium-gain antenna (gain: 12.7dBi) were carried out on the Indian Ocean and with low-gain one (5.8dBi) on the North Pacific. This paper describes the system and the results of the ship experiments using the low-gain antenna.
The low-gain antenna used was a single-element of circular patch one and had a wide beam width. This is considered to cause multipath fading and deteriorate the system performance particularly when the satellite elevation angle (EL) is low. The main purpose of the experiments is to investigate the system performance at the low EL.
The experiment items are as follows: (1) radio propagation (2) data communication and (3) ranging. Propagation experiments showed the fading range was about 3 dB at the EL of 40 degrees and increased rapidly as the EL became low. The performance required for data communication is the bit error rate of 10-5. This performance was attained at C/N0=46dBHz even at the low EL, when error correction and bit-interleave techniques were used. Our goal for the ranging experiment is the accuracy of 100 m rms and was reached at C/N0=43dBHz in the experiment. However the rate of successful ranging was about 50% even at C/N0=45dBHz. This low rate may have much influence on the system performance.
