There are some shortcomings in the existing target height compensation algorithms

such as unreasonable model assumptions and unstable application effect.To avoid these defects

the problem of tracking the aerial target in 3-D space with a 2-D radar was restudied under the assumption that the target flights at a constant speed and a fixed altitude and the radar can obtain the indication information of the target from other collaborative detect units.First

on the basis of the transformation relation between different coordinates

an exact formula of the target height was deduced.Then utilizing identical transformation and reasonable approximations

an approximate estimation formula of the target height was derived.And the error in the formula was calculated using absolute value inequality and Cauchy-Schwarz inequality.At last

combining the original measurement equation of the 2-D radar with the target height estimation equation and using extended Kalman filter

the target space state was estimated.The simulation result shows the proposed algorithm can effectively compensate the target height information and obtain the stable and reliable estimation of the target space state

which can be used in the actual projects as the effective and perfect method for the target space state estimate problem of the 2-D radar.