Laser rangefinders are often used in aerospace. Apollo 15 brought a set of special equipment when it landed on the moon - a large corner reflector, which was used to reflect the laser beam emitted from the earth and record the round-trip time. Calculate the distance between the Earth and the Moon. At the same time, laser rangefinders are also used in other fields of aerospace:
1. Application of laser ranging in terrain survey and surveying Laser
Rangefinders in terrain survey and surveying are generally called laser altimeters, which are mainly mounted on aircraft or satellites to measure elevation data. For example, the laser altimeter of "Chang'e-1" and "Chang'e-2" is one of the main payloads of the lunar exploration satellite, and is responsible for the scientific mission of obtaining three-dimensional elevation data on the lunar surface. The "Chang'e-1" satellite was launched in 2007, and the "Chang'e-2" satellite was launched in 2010. Its elevation data were combined with images from the CCD stereo camera to obtain the basic topography of the lunar surface, divide the structural units, and initially compile a map of the lunar surface. Geological and structural outline map. In addition to elevation data, the "Chang'e-2" laser altimeter also obtained lunar surface reflectivity information, which provided reference data for subsequent soft landings.
2. Application of laser ranging in autonomous landing of spacecraft
Using unmanned probes to land on the surface of target celestial bodies such as the moon, Mars or asteroids for on-site exploration or even sample return is an important way for humans to explore the universe, and it is also one of the hot spots for the development of deep space exploration activities in the future. Launching satellites or probes for soft landing on the surface of other planets is an important direction for space exploration.
3. Application of laser ranging in autonomous space rendezvous and docking
Autonomous rendezvous and docking in space is an extremely complex and precise process. It includes two parts of spatial operations that are connected to each other: spatial rendezvous and spatial docking (Rendezous and Docking). The rendezvous process refers to the meeting of two or more aircraft at a predetermined position and time on the space orbit. The operating distance is 100km to 10m. From far to near, GPS guidance is required, and measurements of microwave radar, lidar, and optical imaging sensors are required. Means, space docking refers to two aircraft meeting in space orbit and then mechanically connecting them into a whole. The action distance is 10~0m. It is mainly completed by using the advanced video guidance sensor (AVGS).
The autonomous space rendezvous and docking mainly consists of four stages: the ground guidance stage, the automatic homing stage, the final approach stage and the docking and closing stage. At the beginning of the rendezvous and docking process, the tracking spacecraft and the target spacecraft are relatively far apart, and the ground needs to participate in tracking and measuring the tracking spacecraft and the target spacecraft. With the support of ground measurements, the tracking spacecraft maneuvers and flies into the sensitive The spacecraft can capture the target spacecraft within the range. At this time, the distance between the two is less than 100km. Generally, microwave radar and GPS are used to navigate together to guide the tracking spacecraft to a range of 20 to 30km from the target, and then the space rendezvous lidar is used. For precise navigation and positioning, the space rendezvous lidar must be used for navigation from this time to the docking. It can be seen that lidar plays an important role in space rendezvous and docking. The optical sensor is activated when the target is 100m to 200m away, and the docking sensor is activated within 10m until the docking is completed. From June 16 to 29, 2012, our country successfully organized and implemented the manned rendezvous and docking mission of Tiangong-1 and Shenzhou-9, achieving another major breakthrough in my country's space rendezvous and docking technology, marking the achievement of the strategic goal of the second step of the project. An important and decisive development. After the spacecraft entered orbit, it was guided by the ground over long distances and flew under autonomous control. At 14:14 on the 18th, it completed automatic rendezvous and docking with the Tiangong-1 target aircraft on a near-circular orbit 343 kilometers above the ground, forming a combination. body. The Tiangong-1 and Shenzhou-9 manned rendezvous and docking missions successfully achieved new breakthroughs such as the first manually controlled rendezvous and docking of astronauts, the first time astronauts stationed on the target aircraft for rendezvous and docking, the first time Chinese female astronauts entered space, and the first long-duration flight. , completed a series of space science experiments and technical experiments, obtained a large amount of valuable experimental data, accumulated important experience and created favorable conditions for the construction of my country's manned space station.
4. Application of laser ranging in the field of space debris detection
The detection of space debris is one of the important application fields of current deep space laser detection technology. The United States and Russia, which have been conducting space activities for a long time, generate more than 90% of the total space debris. No one can count the exact amount of space debris. Humans can currently only track and monitor debris with a diameter of more than 10 centimeters. There are currently more than 17,000 such debris. Only the United States and Russia in the world have the ability to monitor all of them. NASA provides each debris with All are numbered. It is estimated that there are tens or even hundreds of millions of debris smaller than 1 cm. Spacecrafts cannot avoid collision with them and can only deal with them by strengthening their own protection capabilities. In order to develop and utilize space resources safely and continuously, it is necessary to continuously improve the tracking and monitoring technology of space debris, enhance the ability to analyze and predict the space debris environment, and at the same time seek effective measures to control space debris. Space debris monitoring can be carried out in two ways: ground-based monitoring and space-based monitoring. Generally speaking, large-scale space debris mainly relies on ground-based means; medium- and small-scale space debris detection can rely on space-based means. Detection equipment for space-based remote sensing detection includes optical telescopes, microwave radar, and lidar. LiDAR detection systems based on laser ranging technology have unique advantages in space debris detection. It adopts active detection mode and is not limited by lighting conditions. It has narrow beam, long detection distance, high spatial resolution and high measurement accuracy.
5. Application of laser rangefinder in military
Many photoelectric search and tracking systems on fighter jets and land combat equipment are equipped with laser rangefinders, which can accurately know the enemy's distance and prepare for defense accordingly. Among them, some land combat weapons, such as land combat rifles, are equipped with laser rangefinders, which can know the distance between the enemy and ourselves. With the application of laser rangefinders in the military, people are also constantly studying laser weapon detection systems.
Meskernel have mainly focused on the field of laser measurement and control, Laser Ranging Module, Laser Distance Sensor, Laser Rangefinder Module as long as Laser Distance Meter, Laser Rang Finder and 2D 3D LiDAR.
