Patent ID: 6040797
Filing Date: 2000-03-21
Classification: G01S

Abstract:
A method of detecting a radar target in the presence of clutter, in whichthe echo signals received by a radar system, which include both radar targets and clutter, are converted into the video range such that digitized pulse-height values are present, which correspond to the echo signals and correspond to the amplitudes of the echo signals in the video range;the digitized pulse-height values are evaluated by means of a radar-target extractor;a measurement window of a predeterminable size is formed in the radar-target extractor, the window corresponding to a predeterminable monitoring region having a predeterminable area;a threshold value corresponding to the clutter is determined for the measurement window from the pulse-height values present there; andthe pulse-height values present in the measurement window are compared to the threshold value, and an echo of a radar target is recognized when a pulse-height value exceeds the threshold value, characterized in thata frequency distribution is determined for all pulse-height values within the measurement window;starting from the smallest present pulse-height value, having the associated frequency (H.sub.0), the pulse-height values are added until a first predeterminable component of all of the pulse-height values present in the measurement window, the component amounting to 50% in a Gaussian distribution, is detected;the pulse-height value (i.sub.M) associated with this predeterminable first component is determined and established as the average value (M) of all pulse-height values within the measurement window;the addition of the pulse-height values continues until a second predeterminable component of all of the pulse-height values present in the measurement window, the component amounting to 84% in a Gaussian distribution, is detected;the pulse-height value (i.sub.M+S) associated with this predeterminable second component is determined;the standard deviation (S) is determined from the difference between the pulse-height value (i.sub.M+S) associated with the second component and the pulse-height value (i.sub.M) associated with the first component, according to the formula S=i.sub.M+S -i.sub.M ;a hit-recognition threshold TEK is determined according to the formula TEK=Function(M, S, P.sub.fa), whereFunction=a predeterminable function;M=the average value of the pulse-height values;S=the standard deviation; andP.sub.fa =a predeterminable false-alarm probability; andwithin the measurement window, each pulse-height value is compared to the hit-recognition threshold TEK such that a pulse-height value larger than the hit-recognition threshold TEK is assessed as being associated with a radar target.