This paper gives a novel All-Fiber laser Doppler Velocity Sensor(ALDVS) to measure the relative velocity to the lunar
or planetary bodies during the vehicle landing phase. In the beginning of the paper, A brief description of the principle of
laser Doppler velocity sensor is given. After that, the paper gives the laser Doppler velocity sensor configuration. The
paper introduce the helicopter flight test that was held in Zhengzhou. The altitude of flight is about 3km.The laser
Doppler velocity data is analysed. The GPS velocity data and laser Doppler velocity sensor velocity information are
compared. Finally, the equivalent distant in moon is calculated and the measurement error is discussed.
The design and performance of Optical frequency modulation continuous wave (OFMCW) coherent laser radar is presented. By employing a combination of optical heterodyne and linear frequency modulation techniques and utilizing fiber optic technologies, highly efficient, compact and reliable laser radar suitable for operation in a space environment is being developed.We also give a hardware structure of the OFMCW coherent laser radar. We made a detailed analysis of the measurement error. Its accuracy in the speed range is less than 0.5%.Measurement results for the movement of the carrier has also made a detailed assessment. The results show that its acceleration vector has better adaptability. The circuit structure is also given a detailed design. At the end of the article, we give the actual authentication method and experimental results.
Because laser is scattered and attenuated acutely by the water, diffuse reflection of Gauss laser pulse comes back with discrete single photon. These discrete single photon can not form a complete echo wave corresponding to original laser wave. The detector can only output discrete pulses with probability of η(quantum efficiency) . The discrete pulses caused by echo wave, background light, electron hot emission of detection do not have distinct different characteristics in time domain or frequency domain, so echo wave can not be distinguished from these discrete pulses by traditional detection method.
Through analysing the signal and noise statistic characteristics., we put forward a method that apply known probability model to detect probabilistic echo signal to resolve the problem hereinbefore mentioned images.
The signal is very low in underwater laser ranging, so it is very difficult to recognize the echo wave. This paper introduces n method and uses it to process the signal. digital threshold detection is simulated with laser ranging radar and we get good results. This study will help to greatly improve the ability of laser ranging radar.