Satellite interference location system using on‐board multibeam antenna

In satellite communication using a high-gain on-board antenna, there may be a problem with up-link interference, which depends on the directivity of the on-board antenna or the position of the satellite on the orbit. In order to cope with radio frequency interference, it is important to locate (specify) the position of the interference wave radiation source, as seen from the position of the satellite. Technical difficulties are that the characteristics of the interference wave are unknown and there is a limit in the installed weight, making it difficult to add dedicated on-board equipment for location. In a conventional location system, the wave is received simultaneously by two or more satellites. Correlation processing is applied on the ground to the interference waves in order to estimate the location of the radiating source based on the frequency and time differences. In this paper, the following location system is discussed. Angle measurement, based on the received amplitude comparison of multiple beams, is applied to the interference, overlapping with the communication signals received by the multibeam satellite antenna where the interference power ratio between the beams is measured on the ground. A feature of the system is that the source can be located using only a single satellite and no additional on-board equipment. An experimental system was constructed using the S-band multibeam phased array antenna on the experimental Engineering Test Satellite VI. The results of the experiment, for an interference source with known position and for a radiation source with the properties of a radar wave with an unknown position, are presented, together with a discussion of the estimation error and of its improvement.