Research On The 3MMW Wave Band Active/Passive Detecting Technology

The target identification, electromagnetic compatibility(EMC) and the electriccircuit design of signal processing in the three millimeter wave band active/passivecompound detector are systematically studied in this dissertation, which is an importantpart of the national advanced research project.The millimeter wave detecting system used in the target homing of the smartmunitions is an extremely important research domain. At present, the millimeter wavedetector is often used in the anti-armor target precision guidance and the terminalsensitive projectile, its detection unit are usually multimode systems, such as active radarand passive radiometer. The target of search, recognition and tracking are carried out byradar of the millimeter wave detector in the far distance. When the range to the target iscloser, the error of angle measurement is quite serious, even the target is lost because ofthe radar target angular Glint. While the passive radiometer can overcome thisshortcoming, and the more important is that it dose not launch the electromagnetic wave,so it has the very high hiding and the very good resistance to interference. Under thesame condition, it is smaller than the radar, and the consumption energy is also fewer.The active/passive compound detector can makes up for one's deficiency by learningfrom another's strong points and improve the performance of detecting by combiningradar and radiometer, which becomes the development trend of the millimeter wavedetecting technique.At present, there are mainly three systems in the millimeter wave active/passivecompound system: passive falls behind to active at same frequency, active/passive inturn time-sharing at same frequency, and active/passive at different frequency. In thispaper the three millimeter wave band active/passive detector in turn time-sharing work isstudied, which overcome effectively the insufficiency of less information and lowertarget identification rate in the system of passive falls behind to active at same frequency,and which is simpler, smaller and lighter than the different frequency system.In the target identification of active radar, a method of target identification base onGabor atom transform and support vector machine(SVM) is studied in this paper. TheGabor atom transform's validity in signal expression and the SVM's advantage in signalclassification are utilized in this method. In the target identification of passive radiometer, a method of target identification based on gray correlation analysis is introduced in thispaper. The two methods above both solved the target characteristic fuzzy as well as thesystem work timely request. Then, the results of target identification in active/passivechannel are fused at the decision-level by using the D-S evidence theory, thus the abilityof target identification of detector can be improved greatly.IF amplifier used in Common in the active and passive channel is designed under thepremise of guaranteeing the signals of active/passive not to be distorted as far as possible,which causes the system volume to be smaller and the cost to be lower. And a type ofpulse modulator used in three millileter band IMPATT is designed independently. A fastalgorithm of eliminating pulse-modulated signal crosstalk to the passive signal based onshift step prediction is studied in this paper, which can carry out by hardware and hassolved the insufficiency of strict request to signal and long time of running in the methodbased on adaptive filter. According to the studies above, hardware scheme and correlativesoftware of ranging circuit, target identification and information fusion are designed withDSP chip, and the partial debugging of system and experiments outdoor have beenaccomplished.