A Maritime Target Location Method Using Geometric Semantic Constraints Based on Spaceborne GNSS-R

The use of global navigation satellite system reflectometry (GNSS-R) to detect and locate maritime targets is currently attracting considerable attention from researchers. However, some difficulties in detecting and locating maritime targets based on GNSS-R remain. First, targets are difficult to detect due to the influence of sea clutter; second, the low resolution of the delay-Doppler map (DDM) leads to low location accuracy. For maritime target detection, this study proposes a DDM symmetry-based target detection algorithm that can be used to supplement previous target detection methods. For location, this study proposes a maritime target location method using geometric semantic constraints based on spaceborne GNSS-R. Comparing the results of direct location and linear semantic constraint location of the South China Sea No. 4 (SCS-4) shows that after using geometric semantic constraints, the absolute accuracy increased by an average of 2.73 km and the relative accuracy increased by an average of 32.32%. This method can help improve the location accuracy of CYGNSS for maritime targets.