Design Of GPS Jammer Based On DDS Technology

In this thesis, the composition and emergence of GPS signal were introduced,the processing of spread spectrum and correlation reception of GPS signal in thecommunication process were discussed, and the impact of different disturbanceregimes on GPS signal was analyzed in accordance with the features of the signal,on this basis the GPS signal was disturbed. Here the interfering signal’s carrierfrequency aligns with GPS signal’s carrier frequency precisely, implementingrepressive interference of the noise and disabling the GPS receiver.The synthesis of interference signal takes direct digital frequency synthe sistechnology as its core and applies the pseudo-random sequence which is generatedby ARM microprocessor and is similar to spreading codes of navigation message.Then the sequence is loaded into the DDS chip and phase modulation is conducted.Furthermore, the signal which is modulated from pseudo-random sequence iscombined with LO signal which is synthesized with phase-locked loop, andconverted signal is gained, and the interference signal spectrum is aligned withGPS navigation signal spectrum, finally the objective of repressing interference isachieved.On the basis of the above theoretical analysis and design proposal, the designof schematic circuit diagram and PCB, circuit debugging and softwareprogramming are conducted, and the prototype jammer trial which is based on DDStechnology is achieved. Through testing, the interference of GPS signal is realizedand the effect of suppressing GPS navigation signals is attained.