The non-contact speed measurement over ground (SoG) is a key component of modern vehicle technology since it allows measuring the speed of a vehicle without tapping on the wheels and can be measured without slippage. Applications can be found wherever an accurate measure of
speed is needed, i.e., automatic control operations such as anti-lock braking system (ABS), Electronic stability control (ESC) or vehicle intelligent positioning system. The microwave Doppler principle is particularly suitable here because it is the least affected by environmental
influences such as rain, snow, fog, temperature, wind, pollution, compared to other contactless measuring systems, i.e., Global Positioning Systems (GPS), ultrasonic, acoustics and optical sensor. The present work closes a gap in microwave SoG by developing and examining a SoG system based on a four beams radar configuration. Compared to the previous single and dual-beam measuring method, a 4-beam system is capable of estimating the speed vector of the vehicle. Furthermore, this system can minimise the effect of vehicle dynamics on the estimate of vehicle speed. Regarding the Doppler signal processing method, a distinction is made between other known estimation methods. We proposed two types of Doppler processing based on Fourier transform. Theoretical evaluation of these two methods shows that they produce an accurate estimate of mean Doppler frequency. Comparison between these two methods shows that the cross-correlation method produces more accurate estimates and can work at lower input SNR. Finally, evaluation of the developed SoG system with actual road conditions shows that the SoG system can work well on both on-road and off-road conditions with increased speed accuracy when using the cross-correlation method.