A deghosting method for locating communicating transmitters using asynchronous direction finders

When several unknown communication sources are to be located, ghosts appear . These ghosts must be eliminated. Since the conventional deghosting method s compare the characteristics of the received signals, the direction finder s need to measure the same frequency ranges at the same time. However, when the communication sources using Multiple Channel Access (MCA) are located or arbitrary direction finders are used for locating, it is desired that th e operation of the direction finders be asynchronous. If the communication sources carry out intermittent communication, a deghosting method using the difference of holding time is conceivable. Hence, a method is proposed for deghosting in terms of the degrees of similarity between patterns of commu nication history, which is formed from the observation times of the identic al communication source by an identical direction finder. In this method, a scale parameter is introduced to clarify the similarity of the patterns of communication history. By forming the patterns of communication history ta king into account this scale parameter, the deghosting performance is impro ved. By computer simulation, it is confirmed that the deghosting performanc e is improved compared with the case in which the probability of communicat ing at each time is used as the pattern of communication history. (C) 2000 Scripta Technica.