Antenna Array Design And Signal Processing For Ultra-Wide-Band Insect Radar

Insect radar is a relatively advanced technique for observing the ecological behavior of insects,and will be developed with the progress of modern radar detection technology.This type of radar is mainly pulse radar.The radar is to use pulse transceiver switch conversion exists time difference can be detected at a distance to the speed,number,orientation and other information of insects.As pulse radar has a detection blind spot at an altitude of up to one hundred meters from the ground,it is difficult to detect insects flying at low altitude based on the kind of radar.Most insects capture food and reproduce at low altitude.The main areas of insect activity are above the crop canopy to a few tens of meters below.Doppler radar can detect insects at an altitude range of 100 meters.Operating band of the radar is more narrow.The drawback leads to detecting fewer insect species.The study of ultra-wide-band(UWB)insect radar based on log-periodic antenna arrays was proposed.As log-periodic antenna is a kind of frequency independent antenna with UWB characteristics,the log-periodic antenna circular array was used to the study of UWB insect radar.The circular array can adjust the physical aperture to improve the insect detecting effect.However,the array is limited to the surface array design.It is not conducive to UWB insect radar to acquire target parameter information in multiple dimensions.A conical conformal array of log-periodic antennas for UWB insect radar was designed.It can form flat arrays and three-dimensional arrays of different diameters by adjusting the height of the control lever on the conical conformal array.It is capable of detecting many different body size insects by variable focal length on a fixed base.Computer simulations were performed to analyze the problem of estimating the two-dimensional angle of arrival of insects by a conical conformal array.For making the radar search and capture targets faster and more accurately,the improved multiple signal classification(MUSIC)algorithm was proposed.This algorithm greatly reduced the computational complexity while maintaining the estimation accuracy.The relationship between computation time and precision of classical MUSIC algorithm increases exponentially,while the relationship between computation time and precision of improved algorithm increases linearly.The main work results are summarized as follows:1.The circular array of log-periodic antenna was analyzed.The detecting effect of insects was improved by adjusting the radius of circular array under the condition of corresponding signal-to-noise ratio.2.A conical conformal array based on a log-periodic antenna was designed.The array has UWB characteristics to detect insects of different sizes and can change the position of the oscillator and polarization information by adjusting the angle of the cone top angle.The information of insects flying at low altitude was obtained by more dimensions.3.MUSIC algorithm with adjustable step size was proposed for performing spectral peak search.The operation time was reduced by adjusting the step size to narrow the peak search range.Simulation experiments demonstrate the superiority of the proposed algorithm.