The Design And Implementation Of GPS Retransmitted Jamming Prototype

With the development of the technology, The Global Position System has been used widely. The new application of GPS technology in the military field is how to destroy enemy Navigation system and enshroud effectively ourselves utilizing the GPS counter technology.In the GPS interference technology, the retransmitted jamming has the advantages of low sending power, unawareness of the PRN code structure of GPS signal and simple implementation.The retransmitted jamming principle is studied in this dissertation. Based on the analysis of the GPS position theory, the effect of jamming prototype is studied and every part of the jamming prototype is analyzed. The design and implementation of jamming prototype have been done too. The retransmitted jamming method mainly makes use of signal's natural delay, so the jamming signal is completely the same as navigating signal, except for the differently delay time.Besides, the power of retransmitted jamming signal is greater than the navigation signal, so GPS receiver will probably receive the jamming signal, which results in it's getting the false pseudo range and not being position precisely.At first, in the field of GPS retransmitted jamming theory, the position and retransmission jamming mechanisms are described in detail in this dissertation.The jamming effect is analyzed, and jamming effect are researched in detail. Then various working states of jamming prototype is studied. In addition, the function of jamming prototype is the modularization designed. The whole module is divided into three parts including signal-receiving unit, jamming signal generation unit and jamming signal transmission unit, and the function of each part is described. By designing and implementing the analog signal delay module, the system accomplishs real-time continuous signal delay function. The converters of analog-to-digital and digital-to-analog are controlled by FPGA, the signal's store-and-forward function is implemented by FIFO memory, the delay time is decided by the depth of storage. At last, the test for retransmitted jamming prototype is carried out, and all cases are analyzed.