A full-waveform lidar system based on coaxial dual-channel data acquisition

Abstract

The invention discloses a full-waveform laser radar system based on coaxial two-channel data acquisition, breaks through the limit that a conventional laser radar can only measure a limited number of distance and strength data, and simultaneously solves the dead zone problem of non-coaxial laser radar detection. The full-waveform laser radar system based on coaxial two-channel data acquisition comprises a pulse laser, a laser transmitting and receiving unit, a data acquisition unit, a control unit and a software unit, wherein the control unit controls the pulse laser to transmit laser pulse; the laser pulse is divided into outgoing beam, acquisition card control signal generation beam and transmitted waveform recording beam after passing by the laser transmitting and receiving unit; the outgoing beam is scattered by a target, then collected into the data acquisition unit by the transmitting and receiving unit and collected as a receiving signal; and the software unit is used for providing a man-machine interaction interface. The system can store a complete waveform for transmitting and receiving the laser pulse, so that the detectivity of the full-waveform laser radar is effectively enhanced.

Description

technical field [0001] The invention relates to the field of laser radar measurement, in particular to a full-waveform laser radar system based on coaxial dual-channel data acquisition. Background technique [0002] Lidar is an active remote sensing technology with the help of laser. It mainly measures the time for laser pulses to travel between the target and the LiDAR platform, and obtains the distance between the LiDAR platform and the target according to the relationship between the distance and the speed of light and time. The action of the scanning device, the laser radar can complete the scanning of the target surface, and combine the position and attitude data of the laser radar platform to obtain the digital surface model and digital elevation model of the target. Due to the fact that the pulse laser used in practice has a certain divergence angle, the emitted laser pulse beam propagates forward in the form of an approximate cone. When the laser pulse beam interacts...

AI Technical Summary

Problems solved by technology

Due to the fact that the pulse laser used in practice has a certain divergence angle, the emitted laser pulse beam propagates forward in the form of an approximate cone. When the laser pulse beam interacts with the target, it is no longer a point, but a A circular spot, which is called a laser spot, and due to the complexity and diversity of targets in the measurement environment, a laser spot may contain multiple scattering targets or a target has multiple scattering surfaces, resulting in laser The complexity of the pulse echo signal waveform, such as multiple pulses in one echo or pulse stretching

However, the conventional lidar only obtains the distance value of one or more targets in the laser spot by means of a certain threshold method (rising edge, peak value or center of gravity, etc.) (up to 6 at the present stage), and because different targets have different echoes waveform, so only a fixed threshold detection method will result in different ranging accuracy for different targets

Although some foreign manufacturers can provide laser pulse echo acquisition modules, but the price is expensive

On the other hand, the laser radar at this stage adopts an approximately coaxial measurement method (the outgoing optical path is parallel to the echo optical path), which will cause the loss of echo energy, close-range blind spots, and the complexity of adjusting the parallel optical path

Finally, due to the instability of the laser in the lidar, the laser pulse waveforms emitted in each measurement are different. If this difference is not considered in the subsequent data processing, the measurement accuracy will be reduced.

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