This paper analyzes and compares existing variety of LDV technologies. According to existing LDV's deficiencies such as limited signals processing ability, poor adaptability and low precision, a new design scheme of LDV based on digital signal processing is introduced in this article. Doppler signal processing systems processes the spectrum by DSP. The system consists of a filter, a wave detector, an A/D converter and buffer. DSP system samples digital signals and performs Fourier Transform, and the information of velocity is obtained. To achieve a high signal to noise ratio (SNR), many signal processing techniques are applied, such as inserting zero, signal window, the algorithm of periodic diagrams based on FFT and the algorithm of approaching peak value, all of this highly improve the noise adaptivity. In recent years, the spectrum zooming technology is developed quickly, the algorithm of Zoom-FFT based on complex modulation improves the analysis precision, calculation efficiency, resolution and flexibility effectively. In this paper, the time domain sampled signals are windowed firstly, then the zooming analysis via Zoom-FFT algorithm is implemented, and at last,the energy Centrobaric rectifying algorithm is applied to do further estimation. Simulation results indicated that the algorithm has many merits, such as anti-jamming, high accuracy and a small amount of computation.