Research On Airborne Life Signal Detection System And Its Vital Signal Extraction Algorithm

In recent years,ultra wideband radar which has strong penetrating ability and high range resolution advantages in moving target tracking,through geological survey,life rescue,counter-terrorism,city pipeline detection and other military and civilian fields exist in many applications.However,even the small size of the ultra wideband radar in the operation is still dominated by human transport,vulnerable to bad terrain and obstacles,greatly reducing the efficiency of rescue and detection.So the rotor aircraft equipped with radar portable life idea came into being,the life detector can achieve flight detection of buried targets of life,and can greatly enhance the detection efficiency and to overcome the harsh environment of the inconvenience,with the in-depth study and exploration of science and technology,believe that life flight detectors can have huge potential and the value in the field of life rescue,target tracking and detecting etc.In this paper,the detection method,the search algorithm and the feasibility of the aircraft life detection radar are studied.Firstly,the principle and radar echo preprocessing methods are introduced for life detection;secondly according to the characteristics of the actual flight environment of low SNR,in-depth study of the vital signs detection algorithm;and through observation and study a multi antenna array receiving flight life detection and positioning of target search algorithm to achieve to determine the position of the space of life.The main work and innovative achievements are as follows:Analysis of airborne life detection system.The airborne life detection system consists of two parts: a rotorcraft and an ultra wide band life detection radar.It can realize the accurate and efficient positioning of the target life by the reasonable hardware and software algorithms.To ensure the stability of the high flying aircraft,the detection process as much as possible without jitter,and equipped with GPS positioning device and a height meter to estimate vehicle 3D coordinates,equipped with ultra wideband radar receiving antenna to receive the echo signal through the camera body,observe the situation on the ground.UWB radar by transmitting UWB pulse wave,receiving life echo signal received through the antenna on the aircraft and the signal is transmitted to the ground station or handheld device through a wireless signal transmission mode.Finally,the echo signal of the life body and the position coordinates of the target were obtained by echo preprocessing and life signal extraction.Second: signal enhancement algorithm of vital signsThrough the investigation,simulation and experiment,it is found that the traditional vital signs signal extraction algorithm can hardly get the target body information when the signal noise ratio is reduced to-29 dB.When the vital signs are detected by airborne life detection radar,the interference is more intense,and the traditional life detection algorithm is not suitable for airborne life detection.So this paper puts forward a new enhancement algorithm for vital signs,B-SCAN data obtained by pretreatment of life after traversing the echo signal cross-correlation way to strengthen the vital signs,in the single radar simulation and experiment data show that when the SNR is reduced to-29 dB can still get the vital signs are relatively accurate.Even when the SNR decreases to-35 d B can be roughly seen life position.Then the algorithm is applied to the airborne radar life detection with the traditional algorithm.The experiment contrast enhanced life signal,the traditional algorithm is almost impossible to get the vital signs,and the signal enhancement algorithm in aircraft flight stability and aircraft target life is close to get signs of life,but life is not very accurate position.So it is necessary to improve the signal enhancement algorithm when applied to the detection of life.Third: put forward the method of positioning and searching on the air Because the traditional one of a collection of life detection methods need to select at least four times to get the point detection of periodic signal to prove signs,when equipped with aircraft flight will greatly reduce the life detection efficiency,increase the instability and the difficulty of experiment.So the use of a airborne active ways to increase the detection efficiency of vital signs in flight life detection,this paper takes a four as an example,an airborne transmitting antenna and receiving antenna four,can get 4 different signs are used to extract the vital signs and positioning in an exploration cycle.According to the results of the four different positioning,the best observation point is selected to search the next step,so as to determine the final position of the body and the error range.The simulation results show that the method is effective when the observation points are in the same plane and different planes.Fourth: airborne multi linear array of vital signs detectionIn an airborne four life detection based on the receiving antenna number due to the target of life detection efficiency and accuracy is high,so this paper studies a more linear array of vital signs,and the related simulation experiments.Simulation of ultra wideband radar detection for linear array of vital signs and air breathing signal under the rubble,the design experience of vital signs of respiratory motion simulation model of ultra wideband time-domain vital signs respiratory signal model,through static clutter cancellation and linear trend suppression preprocessing.In the case of the ruins,after scanning the azimuth angle,we can get a number of B-SCAN echo data,according to the calculation of the non focus width,these new B-SCAN data as azimuth estimation.