The Intrusion Detection Technology Based On Lfmicw Radar Research

Intrusion detection means to monitor moving targets around the important facilities. It can make an alert and remind the staff when detecting illegal personnel and vehicles. In order to make the intrusion detection to work in the all-weather, and all-time environment and can monitor and track moving targets in real time, this dissertation study the intrusion detection technology based on radar. The main job of the dissertation is as follows:1. In order to make the radar much simpler, smaller and lower cost, the system and structure of the intrusion detection radar was studied and finally the LFMICW system is chosen to do the study of the relevant technology.2. In face of problem of the detecting moving targets, the LFMICW radar echo signal has been modeled and the methods of extracting distance and velocity information have been obtained; the velocity ambiguity resolution algorithm with dual-frequency is used and it expands the range of detecting speed.3. In order to know the influence of LFMICW radar efficiency caused by the pseudo-random sequences, the specific expression of the LFMICW radar average efficient receipt time is obtained after rigorously deducing, which is the theoretical basis of designing the radar transmit power; the connection between the ratio of the main lobe to the secondary lobe of radar echoes and the length of the pseudo-code is analyzed by simulation.4. Confronting the low ratio of the main lobe to the secondary lobe problems, this dissertation proposed the dual-polarization complementary LFMICW system, which made the ratio improve at least9dB.5. In order to satisfy the function of multiple access in radar networking, the technologies of FDMA(frequency division multiple access), quadrature encode switch, manage the initial frequency and manage the initial time have been studied, as a result the quadrature encode switch technology can not manage the function, while the other three technologies can work well in the LFMCW radar. However, in consideration of the problems of spectral leakage of radar echoes, only the FDMA technology can manage the multiple access function.To sum up, the methods of extracting the invasion targets information have been obtained, the velocity ambiguity problem has been solved, the ratio of the main lobe to the secondary lobe of radar echoes was improved at least9dB, and at the same time the solution of multiple access in radar networking has been managed. All these work provides theoretical basis for the study of intrusion detection radar.