English

The visual LiDAR fusion calibration board improves the detection accuracy of the vehicle navigation system and does not need to be adjusted before sailing

145
2023-08-23 14:12:19
See translation
At present, the navigation system has become an important equipment on ships, aircraft, missiles, automobiles and other navigational vehicles. Laser Doppler radar has become an important development direction in the field of velocity measurement technology because of its high accuracy, good spatial resolution and fast dynamic response.
 
The application of the three-beam Doppler Lidar in the vehicle navigation system can continuously measure the navigation parameters of the vehicle relative to the ground, such as three-dimensional axial speed and instantaneous position, and realize the autonomous navigation, and it does not need to be adjusted before sailing, and it is simple and convenient to use.

With the continuous improvement of the detection performance of multi-beam radar such as SNR and velocity sensitivity in engineering applications, more in-depth research on beam configuration is needed. The vehicle-mounted three-beam Doppler Lidar beam is illuminated by a combined transceiver antenna. Whether direct detection or coherent detection is used, it is desirable to obtain a large echo signal intensity.
 
However, in the actual measurement process, the intensity of the echo signal is greatly attenuated because of light scattering on the rough surface. The bidirectional reflection distribution function (BRDF) of a rough surface can describe not only the optical radiation properties of the surface, but also the directional scattering properties.

Three beam Doppler Lidar uses continuous wave laser for optical mixing (homodyne detection) measurement. After the signal light transmitted by liDAR in the atmosphere, the echo signal and the local oscillator signal of the system generate the difference frequency signal through the optical mixer. When the local oscillator frequency is equal to the emitted laser frequency, the difference frequency is the Doppler shift of the echo signal.

When the three-beam laser illuminates the ground at an oblique Angle, the different beam illumination Angle will cause the different working distance of the beam, which will affect the signal-to-noise ratio of the system. If the installation height of the three-beam antenna is H, the working distance of the beam is R=H/sinα. The SNR of the system monotonically increases with the increase of the remaining zenith Angle. When the signal-to-noise ratio of coherent laser radar is higher than 8dB, the estimated maximum likelihood reaches the Kramerlau lower bound (CRLB).

When the system hardware parameters and algorithms are selected, the sensitivity of velocity measurement is only related to the zenith Angle and decreases with the increase of the zenith Angle. Speed measurement sensitivity can not be too small, otherwise the instrument will fail to respond to the operating speed, usually need to give the practical application of speed measurement sensitivity or can be converted to the index requirements.

Hangxin photoelectric laser radar calibration plate has good stability and can obtain repeated accurate data. Suitable for automatic driving distance, identification testing and remote sensing targets and other fields, the reflectivity is 1-99% optional, does not drop powder and does not change yellow, with nearly perfect Lambert characteristics. Hangxin photoelectric diffuse reflector adopts exclusive spraying process, which can provide a variety of reflectivity splicing diffuse reflector for seamless splicing.

Source: Sohu
Related Recommendations
  • Magdalena Ridge expands the capacity of optical interferometers

    The Magdalena Ridge Observatory has purchased a second-generation off-axis beam compressor from Optical Surface, which will expand the functionality of the facility's optical interferometer.Interferometer is a research tool that combines two or more light sources to create interference patterns that can be measured and analyzed. In astronomy, interferometers combine the light collected by multiple...

    2024-01-05
    See translation
  • Zhongke Yuchen laser welding technology opens up vast space for the welding process of new energy vehicle motors

    The application of laser welding technology in the welding process of new energy vehicle motors is a typical example of Zhongke Yuchen in many welding cases. The main accessories of the automatic laser welding equipment for new energy vehicle motors are imported products, and the welding process is mature and stable.Motor rotorMotor statorLaser welding of motor stator tapThe circumferential wel...

    2023-10-18
    See translation
  • The Science Island team has made new progress in detecting atmospheric formaldehyde

    Recently, Zhang Weijun, a research team of the Anguang Institute of the Chinese Academy of Sciences, Hefei Academy of Materials, made new progress in atmospheric formaldehyde detection, and the related achievements were published on the international TOP journal Sensors and Actors: B. Chemical under the title of "Portable highly sensitive laser absorption spectrum formaldehyde sensor based on comp...

    2023-09-21
    See translation
  • Aerotech announces new control features for laser scanning heads

    Aerotech has upgraded the performance of AGV laser scanning heads through powerful controller functions to enhance scanner control (ESC). The new ESC function of the Automation 1-GL4 2-axis laser scanning head driver is a completely passive control loop enhancement function that ensures higher accuracy in the most dynamic motion.With the increasing demand for higher output laser technology in vari...

    2024-06-04
    See translation
  • Professor Wu Dong's team at the University of Science and Technology of China created a "dancing microrobot" using femtosecond laser composite materials.

    It was learned from the University of Science and Technology of China that the team of Professor Wu Dong of the Micro and Nano Engineering Laboratory of the school proposed a femtosecond laser two-in-one multi-material processing strategy, manufactured a micromechanical joint composed of temperature-sensitive hydrogel and metal nanoparticles, and then developed a multi-joint humanoid micromachine ...

    2023-08-11
    See translation