Lateral velocity measurement and error analysis

Most existing velocity measurement methods can only calculate the radial velocity by Doppler effect. Here, the authors study the method of measuring the lateral velocity. It is found that the lateral velocity influences the changing rate of Doppler frequency over time, which inspires them to measure the lateral velocity by analysing the Doppler spectrum or the quadratic phase of the echo. The relationship between the echoes and the lateral velocity is modelled in this study. Also the mean square error of lateral velocity measurement, including the model error and the estimation error, is also deduced. The influence of the observation time is studied according to the mean square error.