Radar apparatus distinguishing between a real target and background noise by causing their respective emission intensity attenuation degrees to differ

摘要

A radar arrangement is provided in which an object and extraneous waves such as radar interference or white noise are distinguished and displayed in different display forms. The radar apparatus comprises a means for receiving sequentially polar coordinate data obtained from rotation of a sweep. The polar coordinate data is converted into image data of a rectangular coordinate system. The image data is stored and updated for each sweep. Based on at least one of, the planar consecutiveness, or the time-wise continuity of the obtained reception data, a subtraction function is provided wherein the data level of the corresponding image data that is stored and updated is reduced during periods shorter than the rotation of the sweep. Planar consecutiveness indicates the extent to which significant echo data is present around target echo data, and is obtained by acquiring in a planar fashion echo data for each of predetermined amounts in both distance and a heading, centered around the target echo data. Time-wise continuity is an amount that indicates the extent to which significant echo data continues to be present at the same position, and is obtained from the echo data of a past predetermined number of sweep rotations. In the case of an real object, planar consecutiveness and time-wise continuity are generally high. In the case of noise, planar consecutiveness and the time-wise continuity are generally low. Consequently, an object that is actually present is clearly distinguished from noise by setting a low subtraction ratio for that which has a high planar consecutiveness and time wise continuity such as an object, and setting a high subtraction ratio for that which has low planar consecutiveness and time-wise continuity such as noise.