What's the matter with drone detection radar measurements?

Release time:

2022-04-15

UAV detection radar measurement is the abbreviation of laser detection and ranging system. Next, I will explain the connection and difference between laser, radar and lidar.

　　UAV detection radarMeasurement is an acronym for Laser Detection and Ranging System. Next, I will explain the connection and difference between laser, radar and lidar.

1. Laser

Laser, the English name for laser, is the initial combination of "stimulated emission optical amplifier. When electrons in an atom absorb energy, they jump from a low energy level to a high energy level, and then fall back from a high energy level to a low energy level, releasing the energy in the form of photons. Highly consistent photon optical properties of the induced (excited) photon beam (laser). Therefore, compared with ordinary light sources, the laser has better monochromaticness, directivity and higher brightness. According to the working medium, lasers can be divided into four categories: gas lasers, solid-state lasers, semiconductor lasers and dye lasers.

2. Radar

The English name of the radar, RADAR. Abbreviation from Radio Detection and Ranging, meaning 'Radio Detection and Ranging', I .e. finding a target by radio and measuring its position in space. Therefore, radar is also called "radio positioning". Radar is an electronic device that uses electromagnetic waves to detect targets. The radar emits electromagnetic waves to irradiate the target and receives its echo, so as to obtain the distance from the target to the electromagnetic wave emission point, the rate of change of distance (radial velocity), azimuth, altitude and other information (from Baidu Encyclopedia).

3. Lidar

The English names of laser radar and radar: light detection and ranging and radio detection and ranging. From the English name, it can be found that Detection and Ranging are commonly used, that is, detection and ranging. Different lights and radios are different, what is the difference?

The difference between radio and laser is the band of electromagnetic waves. The wavelength of the radar electromagnetic wave (generally cm-dm level) is much larger than the wavelength of the laser wave (generally nm-um level).

Electromagnetic waves are generated and received by different devices.

Lidar, in fact, refers to the laser detection and measurement of distance technology. Why add radar? Radar, as a popular technology and means of detecting and measuring distance, is easier to understand.

UAV detection radar is divided into phase radar and pulse radar, and their measurement principles are different. The principle of phase radar ranging is the same as that of total station, while pulse radar mainly measures the time difference between pulse emission and return. UAV lidar is mainly pulsed.

UAV detection radar is generally a multi-line laser radar. Take Jose Panda 40 for example. It has 40 harnesses from top to bottom, and the angular resolution of different harnesses is different. Due to the vertical distribution of the beam, when the lidar rotates, the three-dimensional coordinates of the scanned object can be directly obtained, because the range of action of different laser beams is different. The laser radar is installed on the mobile platform, and the three-dimensional coordinates of the real world can be obtained, and the amount of data obtained is unmatched by the total station.

WhenUAV detection radarIn motion, if you want to measure the coordinate system, you must combine GPS to measure the coordinate system. The role of known coordinates is the same as that of GPS total station reverse positioning.

Of course, GPS is not enough. We must also obtain the angle with the north direction, and measure the horizontal angle and the zenith angle. Here, these three angles can correspond to the backward orientation in the total station, as well as the horizontal and vertical plates. The analogy of the dial here is a bit inappropriate. It stands to reason that when the multi-line lidar rotates, the horizontal and vertical angles of the laser to the object are known. Specifically, the "horizontal angle and vertical angle" here correspond to the leveling inside the total station. It is impossible for us to level when the carrier moves, but we need to measure this uneven angle.

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Some knowledge points of radar, UAV detection radar manufacturers tell you