Extended Object Observability Analysis With Range Extent Measurement Dimension Loss

Extended object tracking, which can obtain rich information about the object’s shape, size, and orientation, has received widespread attention. The modeling method based on support functions (SFs) or extended Gaussian images (EGIs) needs the down-range measurement and cross-range measurement of the object to estimate the information about the object’s extent. Down-range and cross-range refer to the projection lengths of the object along and perpendicular to the radar line of sight (LOS), respectively. The down-range measurement can be generated from the high range resolution profile (HRRP). However, in some radar applications, limited by the resolution capability in cross-range, the cross-range measurements are unavailable. To track extended objects only using down-range measurements, this article analyzes the observability of the extended object in detail. The analysis results indicate that the observability of the extended object is affected by the dimensions of range extent measurement, and the required dimensions of the range extent measurement for extended object tracking vary under different motion modes. According to the analysis results, when the object performs coordinate turn motion, extended object tracking can be achieved using only down-range measurements. The results of simulation experiments confirm this conclusion. The analysis results presented in this article clarify the measurement conditions required for extended object tracking and expand the application scope of tracking algorithms based on the SF and EGI modeling.