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

1322
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
  • Stratasys Ltd. receives a $120 million investment from Fortissimo Capital

    It is reported that Stratasys Ltd. (NASDAQ: SSYS) announced on February 2nd that it has received a $120 million investment from Fortissimo Capital, an Israeli private equity firm. This transaction directly purchases 11.65 million newly issued shares at a price of $10.30 per share, representing a premium of 10.6% compared to the company's closing price on January 31, 2025. As of press time, it has ...

    02-05
    See translation
  • Laserline completes 70% equity acquisition of WBC Photonics

    Recently, Laserline, a leading semiconductor laser manufacturer in Germany, announced that it has completed the acquisition of a 70% stake in WBC Photonics, a Boston based laser technology expert, marking a significant strategic expansion for Laserline. Through this transaction, Laserline not only expands its product portfolio to include blue laser systems with excellent beam quality (better tha...

    2024-09-20
    See translation
  • Advanced OPA enhances the energy of attosecond imaging ultra short pulses

    The attosecond level ultra short laser pulse provides a powerful method for detecting and imaging ultra short processes, such as the motion of electrons in atoms and molecules.Although ultra short laser pulses can be generated, generating ultra short and high-energy pulses is a continuous challenge. In order to expand the photon energy, photon flux, and continuous bandwidth of isolated attosecond ...

    2024-05-11
    See translation
  • Progress in Theoretical Research on the Mechanism of Liquid Terahertz Wave Generation by Precision Measurement Institute

    Terahertz waves have significant application value in communication and imaging. The nonlinear interaction between strong field ultrafast laser and matter is one of the important ways to generate terahertz waves. The experimental and theoretical research related to terahertz generation media such as plasma, gas, and crystal is relatively sufficient. However, liquid water is a strong absorbing medi...

    2024-03-22
    See translation
  • The emergence of laser engraving glass technology injects exquisite and vivid artistic quality into glass works

    The emergence of laser inner glass carving technology has brought new forms and possibilities of artistic expression to glass art. It not only showcases advanced technology and innovative craftsmanship, but also endows glass works with unique artistry.Firstly, laser engraved glass can achieve very fine and complex carving effects. By penetrating the interior of glass with a laser beam for carving,...

    2023-09-15
    See translation