Research And Implementation Of Multi-Channel Adaptive Anti-Jamming Technology Of GPS Receiver

Global Positioning System (GPS) was developed by the United Stated in the70s, itcould provide users with three-dimensional information of accurate position, velocityand time anywhere and anytime. The technology of GPS was applied to various ofmilitary combat and civil navigation, and it has become the key of future space war.With modern communication environment deteriorating, the GPS signal was easilyjammed because of it’s vulnerability, it resulted in the receivers losing the navigationfunction, so it was particularly important to suppress the interference.Around the problem of anti-jamming in GPS, the paper mainly studied thetechnology of spatially adaptive filtering and adaptive ant colony algorithm（AACA）,and realized the hardware programming of algorithms, the main contents are as follow:1. The composition of GPS System and the principle of GPS receiver wasintroduced, and the performance of4antennas array of “Y” type was analyzed.2. Because the choice of algorithm had a direct impact in the performance ofanti-jamming, the paper mainly studied the power inversion algorithm based onLinearly Constrained Minimum Variance (LCMV), and analyzed the statisticalSampling Matrix Inversion algorithm (PI), the iterative Least-Mean-Square (LMS)algorithm and Normalized LMS (NLMS) algorithm, the result showed the SMIalgorithm had the optimal performance.3. The traditional PI algorithms’ null steering was wide when the interference wasweak, it increased the possibility of distortion response when the direction of desiredsignal was close to the direction of interference. Aiming at the disadvantage the papermainly studied the AACA algorithm, it had narrow and deep null steering when theinterference was weak. But it had the disadvantages of large amount of calculation andmultiple null steering, the paper proposed an improved AACA—predicted the range ofthe set of the candidate weight through NLMS algorithm and redistricted the searchdomain. The two algorithms’ performance was analyzed, and the results showed that thepredicted AACA could overcome the disadvantages and had a outstanding performancein suppressing weak interference。 Finally, the paper realized the hardware programming of SMI algorithm、NLMSalgorithm and LMS algorithm based on chip xc6vsx315t of Xilinx company withVerilog Hardware Description Language (HDL). With the help of simulation softwareMATLAB, the author finished the debugging of the algorithms. The test results showedthat the algorithms could suppress the interference effectively.