In this article, the author explains the feasibility and benefits of using Geiger-mode avalanche photodiode (GmAPD) arrays for long-distance detection of several kilometers. The article describes the simulation of the Geiger detection sensor, which is part of the author’s end-to-end laser pointer simulator, which is used to generate simulated 3D laser pointer images from synthetic scenes. The generated 3D point cloud was compared with the experimental acquisition of similar scenes with GmAPD 3D camera.
The operating conditions of long-distance detection are given: copper cables protruding above the ground, experimental system 1 km away, and horizontal line of sight (LOS) maintained. Observing such small objects from a long distance strongly proves that the GmAPD focal plane array can be easily used for real-time 3D mapping or monitoring applications from an airborne platform with good spatial and temporal resolution.
The latest plan proposal for exploring solar system celestial bodies requires accurate position and speed data during the descent phase to ensure a safe and soft landing at a pre-designated location. During landing exercises, the accuracy of the airborne inertial measurement unit (IMU) may be unreliable due to drift in the extended travel time to the destination. The National Aeronautics and Space Administration (NASA) has proposed an advanced Doppler radar system with multiple beams that can be used to accurately determine the state and position of the lander during descent and detect possible hazards in the landing area.
In order to evaluate the effectiveness of this Doppler radar landing system, it is meaningful to simulate the system with different beam numbers and configurations. In addition, the effectiveness of the system in detecting and mapping potential landing hazards must be mastered. This article reports the use of LadarSIM system simulation software to simulate the performance of a multi-beam lidar Doppler system. The details of the simulation method and the performance parameters of Lidar, such as the accuracy of distance and speed, detection and false alarm rate, and the ability of Doppler Lidar to detect and characterize simulated hazards at the landing site are given in the article. Simulation includes modulated pulse generation and coherent detection methods, beam footprint simulation, beam scanning, and interaction with terrain.
This is the first time that a 3D non-scanning imaging lidar instrument has been used to scan the lunar obstacle-like area in flight to construct a 3D green laser pointer digital height map (DEM) to ensure a safe landing site and to be consistent with the experimental guidance, navigation and control system. Guide the Morpheus project’s autonomous rocket propulsion and free-flying lander to land in the obstacle area to a safe location.
Autonomous precision landing and TRL6 demonstration flight test of the Hazard Detection and Avoidance Technology (ALHAT) system, including launch from NASA-Kennedy, a moon-like descent trajectory from an altitude of 250 meters, and landing in lunar-like obstacle areas such as rocks, volcanic craters, and dangerous slopes , The safe location is below 400 meters. The ALHAT project has developed a system for safe and precise manned or machine landing on planetary challenging terrain under any lighting conditions.