LiDAR

LIDAR LiDAR is a remote sensing technology that uses light and emits it in the form of pulses. Compared to laser irradiation, measuring scattered light and analyzing the long-distance and characteristics of objects. This technology of radar is achieved by replacing radio wave radar with light. The distance to an object is determined by the time difference between the emission of light and the receipt of reflected light. Therefore, sometimes the term LiDAR is used, but it should be avoided as it can easily be confused with radar that uses radio waves. Drivers are used in geology, geotechnical engineering, seismology, remote sensing, and atmospheric physics. In recent years, as the sensor of autonomous vehicle
catalogue



1. Lidar

2. Application of LiDAR

LiDAR

LIDAR LiDAR is a remote sensing technology that uses light and emits it in the form of pulses. Compared to laser irradiation, measuring scattered light and analyzing the long-distance and characteristics of objects.
This technology of radar is achieved by replacing radio wave radar with light. The distance to an object is determined by the time difference between the emission of light and the receipt of reflected light. Therefore, sometimes the term LiDAR is used, but it should be avoided as it can easily be confused with radar that uses radio waves.

Drivers are used in geology, geotechnical engineering, seismology, remote sensing, and atmospheric physics. In recent years, as a sensor of autonomous vehicle, it has attracted people's attention.

LiDAR

Application of LiDAR

The third level of autonomous driving technology is conditional autonomous driving, and the fourth to fifth levels that do not require driver driving must have the function of safe autonomous driving on highways and ordinary roads. Therefore, in addition to cameras and millimeter wave radars, riders were also used to ensure sensing redundancy. According to the announcement from Yano Research Institute, the market size of drivers is expected to reach 495.9 billion yen by 2030.


In geology and seismology, the combination of airborne knights and GPS is very useful for measuring crustal displacement caused by faults, uplift, and subsidence. With this system, you can even measure the crustal movement of trees. The Seattle malfunction in Washington became famous for the discovered system. We also compared the degree of uplift of Mount St. Helens caused by the 2004 eruption with the data before and after the eruption.

Airborne/satellite mounted LiDAR systems can also be used for glacier observation. It can measure slight changes. The satellite of NASA (Enzhong) was installed by cyclists for this purpose.

Drivers are applied in various ways in forestry. Drivers on airplanes/satellites can measure hood height, biomass, and leaf area. It is also used as a rapid investigation method for other industries, such as the energy industry, railways, and transportation related fields.

There is a global network that uses mirrors installed by spacecraft on the moon to observe the distance between the moon and Earth, and also uses riders. Due to the fact that the distance to the moon can be measured with millimeter precision, it is very useful for verifying general relativity.


In 1994, the lidar on the spacecraft was equipped with a LITE on the STS-64 and observed clouds and aerosols. NASA's Mars Global Surveyor (launched in 1996) orbits Mars and is equipped with a rider called MOLA (Mars Orbital Laser Altimeter), which can provide stunning and accurate topographic maps. Yes, in addition, NASA's ICESat satellite launched in 2003 was also equipped with GLAS LIDAR for observing ice sheets and the atmosphere. The NASA CALIPSO satellite launched in 2006 carried CALIOP and observed the atmosphere. The ADM Aeolus, planned to be launched by ESA in 2014, is also equipped with LiDAR for wind and atmospheric observation. Japan's xxx lunar orbiter Kaguya is also equipped with a laser altimeter (LALT), which is a driver and obtains accurate terrain altitude data for the entire moon.

Atmospheric physics is used to measure the concentration of several substances in the middle and upper atmosphere from afar. Substances such as potassium, sodium, molecular nitrogen, and oxygen. The temperature can also be calculated by measuring these concentrations. Lidar is also used to measure wind speed and check the vertical distribution of aerosol particles.

In oceanography, the fluorescence of phytoplankton as a whole is estimated based on the biomass of the ocean surface. It is also used for seabed exploration on airplanes that is difficult to measure on ships.

In addition to scientific applications, it can also replace radar for traffic control (so-called mouse traps) to improve speed. Radar law enforcement machines carry a large amount of weight and are often difficult to measure specific vehicles individually, but when using riders, radar law enforcement machines are one of the many vehicles driven by small camera law enforcement machines. Can be targeted. Radar law enforcement aircraft use the Doppler effect to directly measure the speed of an object, but for riders, the speed is calculated from the time it takes for the object to pass through two points.



Although it is still too early to elaborate on military applications, it is well known that research on imaging is ongoing. Due to its high spatial resolution, detailed features of the target (such as water tanks) can be captured. In the military field, it is commonly referred to as the abbreviation of LADAR.

The 2005 DARPA Challenge Autonomous Vehicle Stanley (en) was equipped with five German Sick AG (en) drivers for short distance exploration.

There are two types of riders. One is the scanning type, and the other is the non scanning type. According to the laser scanning method, the former is further divided into several subgroups. They are LLS (beam scanners, laser line scanners) that use thin beams and fan-shaped beam scanners that use fan-shaped beams.

Both scanning and non scanning can be used for stereo imaging. For non scanning types, use so-called gated viewing technology. This method is a combination of pulsed laser and high-speed gating camera. Sweden, Denmark, the United States, the United Kingdom, and military applications have been studied. The three-dimensional image of the number of targets beyond a kilometer can be visualized in the following error at 10 centimeters.

Thomson scattering was measured using LiDAR at the European Torus Collaborative Research Facility (JET) in the UK, and electron density and temperature distribution in plasma were obtained.