Research On Gnss Spoofing Signal Detection And Emitting Source Localization Techniques

The GNSS spoofing interference can drag away the position or time results,which are reported by GNSS receiver,without being awared.It is more harmful compared with other type interferences,which just want to disable the target receiver.Therefore the researches about the GNSS spoofing signal detection and emitting source localization techniques are conducted.The main findings of the thesis are as following:?1?Among all the types of GNSS spoofing interferences,the slowly dragging away type spoofing interference is the most dangerous one.To solve the problem that signal parameters of this type spoofing interference are hard to control,the signal generating model of this type spoofing interfernce is given.The correctness of the spoofing signal generating model is validated by numerical simulations.The spoofing detection methods,that based on signal power,correlaton peak,doppler or pseudo-range residual,were carried out to detect the spoofing signals generated according to the proposed spoofing signal model.The simulation results inlustrate that all the above spoofing detection methods can not detect the spoofing interference.It is further explicated that this type spoofing interfernece is very covert;and the above spoofing detection methods have limitations.?2?To detect the spoofing signals that all coming from the same emmiter,a spoofing detection algorithm was proposed,which detects spoofing signals using pseudo-range single difference,bases on the fact that the spoofing pseudo-range single difference measurements are identical,while the authentic pseudo-range single difference measurements are different.The simulation results show that,when the signal number is 4,under the performance demand that the false alarm rate is 10^-4,the detection probability is 98%,the baseline length requirement of the algorithm using position results is 25 meters,while the baseline length requirement of the proposed algorithm is 10 meters.The baseline length requirement is compressed effectively of the proposed algorithm,which is just 40 percents long of the spoofing detection algorithm using position results.?3?To detect the spoofing signals that coming from different emmiters,a spoofing detection algorithm using pseudo-range double differences measurements was proposed.The spoofing signals are detected by comparing the pseudo-range double differences measurements with the pseudo-range double differences estimations of authentic signals.It does not need to estimate the direction of receiving signals,the computing burden is light,so it is easy to implement.The simulation results illustrate that the detection probability can reach 96.1%,under the condition that the baseline is 10 meters long,the standard deviation of measurement noise is 0.1 meter,the false alarm rate is 10^-4,and the angle between spoofing signal and authentic signal is 15^o.?4?The detection probability of the spoofing detection algorithm is high,which using pseudo-range double differences measurements;however the ratio between detection bland area and overall area is 18.4%.To reduce the detection bland area,for the GNSS equipments loading on the rotation platforms,a spoofing detection algorithm was proposed,by using a rotating antenna which is in uniform circluar movation relative to the platform.The spoofing signals are detected by comparing the measurements of carrier phase single difference between different epochs with the estimations of authentic signals'.Simulation results show that the ratio between detection bland area and overall area is 3.70%for the same spoofing scnario mentioned in?3?,under the condition that the rotation frequency of antenna is 1Hz,the radius of antenna movation circle is 0.1 meter,and the standard deviation of measurement noise is 0.01 wave length.The detection bland erea is 4.92 times smaller than the above algorithm's which using preudo-range double differences measurments.?5?To locate the spoofing signal emmitting source for the scnario that receivers are static and positions are known,under the assumption of direct line-of-sight and free space propagation,a source localization algorithm,using both time difference of arrival?TDOA?measurements and received signal strength?RSS?measurements,is proposed.The simulation results show that the solution accuracy is smaller than 15 meters,and it can reach Cramer-Rao lower band?CRLB?,when the carrier noise ratio of received signal is higher than 44dB-Hz,for near field scnario.?6?To locate the spoofing signal emmitting source for the scnario that receivers are moving with position error and time synchronization error,under the assistant of the measurements coming from the pseudo-satellite,an improved source localization algorithm was proposed,using both TDOA measurements and frequency difference of arrival?FDOA?measurements.The simulation results show that the solution accuracy is smaller than 80 meters,and it can reach CRLB when the carrier noise ratio of received signal is higher than 40dB-Hz.Finally,the main work of this thesis is summarized,and the future work is presented.