Performance Comparison of Spherical and Elliptical Earth Models for Low Angle Tracking in Radars

The problem in tracking a target at lower elevation angles by radars comes due to multipath phenomenon. Specular multipath causes erratic elevation tracking at low target elevations within a beam width of the horizon and causes significant elevation error even at target elevations a few beam widths above the horizon. In this current work, two earth models namely Spherical and Elliptical (based on WGS-84 model) for computing specular multipath effects has been proposed to compute the target elevation angle and their performances are compared. The Complex Angle (CA) is used to estimate the true target elevation angle in the presence of multipath. The result shows that the elliptical earth model gives better elevation estimation than the spherical earth model.