The Research Of Target Location Technology Based On Beidou And Ground Detective System

With the development of wireless communication technology, electronic countermeasure technology has developed rapidly, and passive location technology by virtue of its own radiation without electromagnetic waves keeping "Silent"features, the role of distance, anti-interference ability and other advantages, has already become one of the hot issues in the field of electronic confrontation beyond the active location technology.As a key technology in passive location, DOA location algorithm has always been an important part of the location method .The algorithm calculates the two-dimensional coordinates of the target by obtaining the geographical position of the two intercept points and the azimuth of the target radiation source. Due to the target radiation source from time to time radiation signals and multipath interference and other factors lead to inaccurate positioning problems, a new algorithm is proposed in this paper , which is based on the relationship between the direction finding and the geometric center. The algorithm is analyzed and experimentally verified by the Beidou navigation system. The results show that the algorithm has the validity in passive location.In order to develop a complete passive location system, this paper designs a set of ultra-wideband receiver front-end to receive the signal after the new location algorithm is proposed. The receiver using the superheterodyne structure is mainly composed of a low noise amplifier, a mixer, an ultra wideband frequency source and a filter, where in the receiver the frequency range is 0.6GHz-2.7GHz.The UWB frequency source is the main component of the receiver and can output 0.8GHz?3GHz sweep signal in the voltage control. By using the swept signal as the local oscillator input of the receiver, it is possible to stably output an intermediate frequency signal of 200 MHz to 300 MHz when the receiver receives a radio frequency signal of 0.6GHz to 2.7 GHz.The entire ultra-wideband receiver front-end is fabricated and measured, After the completion of ultra-wideband frequency source and the receiver front-end design.The test results show that the gain of the receiver front-end is greater than 7.5dB.Sensitivity is better than -82.5dBm, the noise figure is less than 4dB, the receiver dynamic range is greater than 90dB. The technical index meets the ultra-wideband receiver system requirements.