Research On Eliminating High PRF Location Ambiguity In Time-Difference Location System

TDOA (Time Differences of Arrival) Location is an important location of passivelocation, because of its good concealment and high precision; it has become a main technicalmethod of Electronic investigation. For the present, as targets transmit High PRF signals toget unambiguous Doppler Field, TDOA location system got location ambiguity problem.These location ambiguities cause a limit to the use of TDOA system, since TDOA unable tolocate these targets with High PRF signals. To solve that, this paper studies single targetlocation ambiguity mainly caused by High PRF signals. The detailed works are as follows:Firstly, the basic TDOA location theory is briefly introduced. Analyzing the source oflocation ambiguity, the method of space division by wide base beam is proposed. Thismethod locks targets into small different space which correspond narrow window of timedifferences. By narrowing scope of time difference, faulse time difference pares are reduced.And effect of this method is tested by a typical beam distribution.Secondly, the method of adding direction information is proposed. By analyzing theDOA (Direction of Arrival) of these location points, algorithm is proposed. And the effect ofaiding direction de-ambiguity method is tested.Finally, this paper studies the trace of location points, and proposes the method of rangemigration. Through analyzing the TOA (Time of Arrival) of main base, the conclusion isinduced that target range movement (called range migration) causes the tiny modulation ofTOA. The principle is only applied for true location point, so testing the principle can choosethe true point from the ambiguous ones. The apply condition is discussed and effect is testedby simulation. Using all the methods mentioned above together, the location ambiguityproblem caused by High PRF signals is well solved.