Airborne high-resolution large-dynamic land and water detection dual-wavelength area array laser radar

Abstract

The invention discloses an airborne high-resolution large-dynamic land and water detection dual-wavelength area array laser radar which comprises a dual-band laser, a transmitting unit, a dual-band DOE group, a beam combining unit, a light beam scanning unit, a receiving unit, a beam splitting unit, a dual-band detector group, an information processing and storage unit and a system control unit. The characteristics of water surface, shallow water area and land strong echoes are fully utilized, a narrow view field adopts an area array detection mode, the amplitude of a strong echo signal is effectively averaged, a high-responsivity area array detector is selected, echo energy is fully utilized, and meanwhile the spatial resolution of the system is improved; the blue-green laser completes water body detection, the near-infrared laser completes water surface detection, and the water surface area array three-dimensional imaging is beneficial to improving the underwater data resolving precision of the blue-green laser.

Description

Technical Field

[0001] The invention belongs to the technical field of airborne optoelectronic imaging, and relates to an airborne high-resolution large-dynamic dual-wavelength area array laser radar for water and land detection. Background Art

[0002] There is a strong demand for integrated land and water detection sensors in islands, reefs, coastal zones and other water-containing and land areas. Traditional ocean laser radars use wide and narrow field of view to improve the dynamic range of water detection. In shallow water areas, unit detectors with lower responsiveness are used or the detection gain of unit detectors is lowered. In deep water areas, unit detectors with high responsiveness or high-gain unit detection methods are used to meet the detection needs of strong shallow water echoes and weak deep water echoes. However, the energy of strong echoes on the surface of water bodies, shallow water areas and land is not fully utilized; in order to ensure the density of seabed laser foot points, the single-point scanning method limits the speed of the airborne platform, the operation efficiency is low, and the land detection requires high point density and high resolution. The integrated land and water detection laser radar faces the problems of multi-domain large dynamic echo detection on land, water surface, shallow water areas, and deep water areas, as well as high-resolution detection of land and water. Summary of the invention

[0003] (I) Purpose of the invention

[0004] The purpose of the present invention is to provide an airborne high-resolution large dynamic dual-wavelength area array laser radar for land and water detection, so as to solve the problems of large dynamic range of signals and high-resolution three-dimensional imaging in the process of integrated land and water detection.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides an airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar, which includes: a dual-band laser, a transmitting unit, a dual-band DOE group, a beam combining unit, a beam scanning unit, a receiving unit, a beam splitting unit, a dual-band detector group, information processing and storage, and a system control unit; a dual-band laser, synchronously and independently outputting blue-green band and near-infrared band dual-band laser pulses; the transmitting unit completes independent collimation of the dual-band laser; the dual-band DOE group forms a spatial sub-beam distribution consistent with the spatial distribution of the detector; the beam combining unit The element adjusts the spatial distribution of the dual-wavelength sub-beam array to achieve the overlap of sub-beams in each band and realize coaxial emission; the scanning unit completes the scanning of the array beam and expands the field of view of ground detection; the receiving unit completes the dual-band common aperture reception to achieve a narrow field of view in shallow water and land and a wide field of view in deep water; the beam splitting unit divides the received beam into a blue-green band beam and a near-infrared band beam; the dual-band detector group receives the split dual-band beams respectively; the information processing and storage completes the distance and intensity information processing; the system control module completes the dual-band laser synchronous output and data clock synchronization.

[0007] (III) Beneficial effects

[0008] The airborne high-resolution, large-dynamic dual-wavelength area array laser radar for land and water detection provided by the above technical solution makes full use of the characteristics of strong echoes on the water surface, shallow water areas and land. It adopts an area array detection method with a narrow field of view, effectively averages the amplitude of strong echo signals, and selects a high-response area array detector to make full use of echo energy while improving the spatial resolution of the system. Blue-green lasers are used to complete water body detection, and near-infrared lasers are used to complete water surface detection. The three-dimensional imaging of the water surface area array is conducive to improving the accuracy of blue-green laser underwater data calculation. In order to achieve deeper water depth detection, a stronger green light laser is required, which is generally obtained by near-infrared laser frequency doubling. Therefore, more near-infrared laser energy is retained, and dual-band area array detection is achieved without increasing the power consumption of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The present invention is a block diagram of the composition principle of the airborne high-resolution large-dynamic land and water detection dual-wavelength area array laser radar.

[0010] Figure 2 This is an optical-mechanical diagram of the airborne high-resolution, large-dynamic dual-wavelength area array laser radar for land and water detection according to the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0012] Figure 1 This is a composition diagram of the airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar system of the present invention, which mainly includes: a dual-band laser, a transmitting unit, a dual-band DOE group, a beam combining unit, a beam scanning unit, a receiving unit, a beam splitting unit, a dual-band detector group, information processing and storage, and a system control unit.

[0013] The dual-band laser synchronously and independently outputs blue-green band and near-infrared band dual-band laser pulses;

[0014] The transmitting unit completes independent collimation of dual-band lasers;

[0015] The dual-band DOE group forms a spatial sub-beam distribution consistent with the spatial distribution of the detector; the sub-beam array is 8×8@532nm and 8×8@1064nm

[0016] The beam combining unit adjusts the spatial distribution of the dual-wavelength sub-beam array to achieve the overlap of sub-beams in each wavelength band and realize coaxial emission;

[0017] The scanning unit completes the scanning of the array light beam, expands the field of view of ground detection, and adopts a prism cone scanning method.

[0018] The receiving unit completes dual-band common aperture reception, realizing narrow field of view reception in shallow water and land and wide field of view reception in deep water.

[0019] The beam splitting unit adopts a dichroic beam splitter.

[0020] The dual-band detector group uses a planar array detector, a single photon planar array or a linear planar array detector for narrow field of view, a Si-APD planar array detector for 1064nm, a MCP-PMT planar array detector for 532nm, and a large target unit detector for large field of view. The 532nm deep water channel uses a PMT unit detector.

[0021] The information processing and storage completes the distance and intensity information processing.

[0022] The system control module completes dual-band laser synchronous output and data clock synchronization.

[0023] Figure 2 This is a simplified optical-mechanical diagram of the system, showing the details of the lidar.

[0024] Among them, the dual-band laser synchronously and independently outputs 532nm and 1064nm dual-band laser pulses.

[0025] The transmitting unit includes two groups of laser collimating lenses, which collimate the 532nm and 1064nm dual-band laser pulses respectively.

[0026] The dual-band DOE group includes two groups of DOEs, and each group of DOEs is arranged on the light-emitting side of a laser collimating lens.

[0027] The beam combining unit includes two folding mirrors, which are arranged on the back side of the two groups of DOEs respectively. The 532nm laser pulse corresponds to the first folding mirror, and the 1064nm laser pulse corresponds to the second folding mirror. The first folding mirror reflects the 532nm laser pulse to the second folding mirror, and the second folding mirror reflects the 1064nm laser pulse and transmits the 532nm laser pulse. After combining the two-band laser pulses, the direction is changed to irradiate the target.

[0028] The beam splitting unit includes two dichroic beam splitters, which split the received light beam into a 1064nm band light beam and a 532nm band light beam, which are respectively received by corresponding detectors after passing through corresponding focusing lenses.

[0029] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An airborne high-resolution large dynamic dual-wavelength area array laser radar for land and water detection, characterized in that: include: Dual-band laser, transmitting unit, dual-band DOE group, beam combining unit, beam scanning unit, receiving unit, beam splitting unit, dual-band detector group, information processing and storage, system control unit; dual-band laser, synchronously and independently output blue-green band and near-infrared band dual-band laser pulses; the transmitting unit completes independent collimation of the dual-band laser; the dual-band DOE group forms a spatial sub-beam distribution consistent with the spatial distribution of the detector; the beam combining unit adjusts the spatial distribution of the dual-wavelength sub-beam array to achieve the overlap of each band sub-beam and realize coaxial emission; the scanning unit completes the scanning of the array beam to expand the field of view of ground detection; the receiving unit completes dual-band common aperture reception to achieve narrow field of view in shallow water and land and wide field of view in deep water; the beam splitting unit divides the received beam into a blue-green band beam and a near-infrared band beam; the dual-band detector group receives the split dual-band beams separately; the information processing and storage completes the distance and intensity information processing; the system control module completes the synchronous output of the dual-band laser and the data clock synchronization.

2. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar according to claim 1, characterized in that: The dual-band laser synchronously and independently outputs 532nm and 1064nm dual-band laser pulses.

3. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar as claimed in claim 2, characterized in that: The transmitting unit includes two groups of laser collimating lenses, which collimate the 532nm and 1064nm dual-band laser pulses respectively; the dual-band DOE group includes two groups of DOEs, and each group of DOEs is arranged on the light-emitting side of a laser collimating lens.

4. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar as claimed in claim 3, characterized in that: The beam combining unit includes two folding mirrors, which are arranged on the back side of the two groups of DOEs respectively. The 532nm laser pulse corresponds to the first folding mirror, and the 1064nm laser pulse corresponds to the second folding mirror. The first folding mirror reflects the 532nm laser pulse to the second folding mirror, and the second folding mirror reflects the 1064nm laser pulse and transmits the 532nm laser pulse. After combining the two-band laser pulses, the direction is changed to irradiate the target.

5. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar as claimed in claim 4, characterized in that: The scanning unit adopts prism cone scanning method.

6. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar as claimed in claim 5, characterized in that: The beam splitting unit includes two dichroic beam splitters, which split the received light beam into a 1064nm band light beam and a 532nm band light beam, which are respectively received by corresponding detectors after passing through corresponding focusing lenses.

7. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar as claimed in claim 6, characterized in that: In the dual-band detector group, a narrow field of view uses an area array detector, a single photon area array or a linear area array detector, and a large field of view uses a large target unit detector.

8. The airborne high-resolution large dynamic dual-wavelength area array laser radar for land and water detection as claimed in claim 7, characterized in that: In the dual-band detector group, under narrow field of view, 1064nm uses Si-APD area array detector and 532nm uses MCP-PMT area array detector.

9. The airborne high-resolution large dynamic water and land detection dual-wavelength area array laser radar as claimed in claim 8, characterized in that: In the dual-band detector group, the 532nm deep water channel uses a PMT unit detector under a large field of view.

10. An airborne optoelectronic imaging system, characterized in that: It comprises the airborne high-resolution large dynamic dual-wavelength area array laser radar for land and water detection as described in any one of claims 1 to 9.

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