Precise determination of the relative velocity between the spacecraft and celestial body is necessary to ensure the secure landing in space exploration. An all-fiber linear frequency modulation continuous wave(LFMCW)-continuous wave(CW)Doppler laser radar was developed for landing navigation. A narrow line width laser was used as the seed laser. The laser frequency was modulated by an acousto-optic modulator. Speed vector was measured in real-time by means of balance coherent detection and digital signal processing based on FPGA. Experiments made on laser Doppler radar with a speed generator proved that 0.05cm/s or better accuracy can be achieved while the velocity direction can be discriminated.