Research On Star - Ball Positioning Method Of Uplink Signal Source

There are several methods for the uplink signal source locating of the GEO-satellite. Nowadays, the most prevail method is using two-GEO-satellites locating system, in which the differential time offset (DTO) and differential Doppler frequency offset (DFO) caused by the retransmitting of two GEO satellites were used to locate the uplink signal sources. In addition, there are still other location systems which using single satellite or multi-satellites. All these systems are dispensed with demodulation and decryption technique. They can not only be used in locating jammers but also uplink signal sources. However, the two-GEO-satellites locating method has difficulty in finding a proper adjacent satellite to form a two-GEO-satellites locating system in sudden affairs. In this dissertation, a new locating method using tethered balloon as assistant active satellite was proposed.Firstly, the combined satellite-balloon locating system which composed of a GEO satellite and a tethered balloon was presented in this paper. The feasibility of this new system applied to the uplink signal source locating was discussed and the accuracy specifications of the locating parameters for this system were advanced. Then, based on the simulated uplink signal and reference signal, the DTO and DFO parameters were extracted by using traditional cross ambiguity function method and a parameter estimation method based on modulation-domain time-frequency separation was proposed, which could extract the locating parameters rapidly and precisely. Based on the results of parameter estimation, the locating sets of equations were formed. The set of equations was solved by pseudo-linearization and the precision was improved by position-iteration method. The location was determined using gridding method in the effective locating area. Finally, based on the error analysis of generalized target locating in the actual satellite-balloon locating system, some influencing factors of location were analyzed and the error ellipse was given.The results of this paper will be directly used in the developing of the satellite-balloon locating platform and its systematic experiment. The results have laid some theoretical and practical foundations for the development of the active adjacent satellite system.