Four-in-one telescope system applied to wind finding radar

Abstract

A four-in-one telescope system applied to a wind finding radar, comprising a laser transmitter and, successively following the laser transmitter, an optical channel changeover switch, four focusing modules, a dustproof protection lens and a telescope assembly, the telescope assembly comprising a plurality of lenses and a lens barrel. The present invention combines four channels into one channel so as to improve the consistency of the system, reduces the numbers of four lens groups, four lens barrels and one lens base of a present telescope so as to decrease material costs, and uses a stress-free rear-end adjustment mechanism for improving the lens installation and adjustment mode so as to reduce the effects of installation and adjustment on the performance of the lenses, thereby further improving the performance of a laser radar.

Description

A four-in-one telescope system for wind radar Technical Field

[0001] The present invention relates to the field of wind measuring telescopes, and in particular to a four-in-one telescope system used in a wind measuring radar. Background Art

[0002] The existing wind radar telescope technology uses four separate telescopes to couple the four beams separated by an optical channel switch. A focusing module then focuses the beams into the atmosphere. Light scattered by aerosols enters the four telescopes and is then coupled into corresponding optical fibers, as shown in Figure 1. Using four telescopes results in low system consistency, difficult focusing, and high costs.

[0003] Summary of the Invention

[0004] The purpose of the present invention is to address the shortcomings of using four groups of telescopes, which result in low system consistency, great focusing difficulty and high cost. A four-in-one telescope system for wind measurement radar is proposed to address this problem.

[0005] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0006] A four-in-one telescope system for a wind measurement radar comprises a laser transmitter, and is characterized in that an optical channel switching switch, a plurality of focusing modules, a dust protection mirror, and a telescope assembly are sequentially arranged behind the laser transmitter. The telescope assembly comprises a plurality of lenses and a lens barrel. The plurality of lenses form an optical transmission system with a field of view of 17°-20°, and comprises a first focusing lens, a second focusing lens, a first aberration compensation lens, and a second aberration compensation lens. The first focusing lens and the second focusing lens are arranged near one end of the dust protection mirror. The first focusing lens and the second focusing lens converge a laser beam with a divergence angle to achieve nearly collimated light output. The image height and aberration compensation are adjusted by the first aberration compensation lens and the second aberration compensation lens to achieve an image quality design far less than the diffraction limit.

[0007] As a further preferred embodiment of the present invention, the number of light beams emitted by the laser emitter is less than or equal to 10.

[0008] As a further preferred embodiment of the present invention, the divergence angle of the light beam emitted by the laser emitter is less than 0.125.

[0009] As a further preferred embodiment of the present invention, based on the transmission of Gaussian light in space,

[0010] The distance l between the first focusing lens (1) and the beam waist is calculated, where l' is the actual far-field focus, F is the focal length of the lens, and f is calculated by f = πω0 2 / λ, calculated, ω0 is the Gaussian beam waist radius, and λ is the wavelength of light.

[0011] As a further preferred embodiment of the present invention, the distance between the first focusing lens and the second focusing lens is set to 0 mm-2 mm, and the distance between the second focusing lens and the first aberration compensation lens is set to 80 mm-100 mm.

[0012] As a further preferred embodiment of the present invention, the first focusing lens and the second focusing lens are both configured to have one side as a flat surface and the other side as a convex surface, and the convex surface of the first focusing lens is in contact with the convex surface of the second focusing lens; both surfaces of the first aberration compensation lens are configured to be concave surfaces, and both surfaces of the second aberration compensation lens are configured to be convex surfaces.

[0013] As a further preference of the present invention, the focusing module includes a focusing mechanism adapter, a fine-tuning knob, a fixed sleeve, a fine-tuning rod and a fiber optic jumper flange; the focusing mechanism adapter is used to assemble the focusing module on the lens barrel; the fixed sleeve is arranged on one side of the focusing mechanism adapter, the fine-tuning knob is arranged on the outside of the fixed sleeve, and the fine-tuning rod is arranged at the end of the fixed sleeve away from the focusing mechanism adapter, and the fine-tuning knob can drive the fine-tuning rod to move back and forth; the fixed sleeve is connected to the focusing mechanism adapter and the fine-tuning rod to maintain high coaxiality; the fiber optic jumper flange is arranged at the other end of the fine-tuning rod, and the fiber optic jumper head is connected to the fiber optic jumper flange; when using the focusing module, the fine-tuning knob is rotated to drive the optical fiber to move back and forth, thereby realizing control of the laser far-field focal position.

[0014] As a further preferred embodiment of the present invention, the stepping setting of the fine-tuning knob is 10-100um, and the total stroke is 10-20mm.

[0015] As a further preference of the present invention, the optical fiber jumper head is configured as an APC interface or a PC interface.

[0016] As a further preferred embodiment of the present invention, the lens barrel is made of a material with low thermal expansion coefficient.

[0017] The four-in-one telescope system for wind radar proposed in the present invention has the following beneficial effects compared with the prior art:

[0018] 1. The present invention combines four channels into one channel, improving the consistency of the system;

[0019] 2. Reduce the number of the current telescope's four lens groups, four lens barrels, and one lens mount to reduce material costs;

[0020] 3. The lens installation and adjustment method has been improved, and a stress-free rear-end adjustment mechanism has been adopted to reduce the impact of installation and adjustment on lens performance, further improving the performance of the lidar. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG1 is a schematic structural diagram of the prior art;

[0022] FIG2 is a schematic structural diagram of the present invention;

[0023] FIG3 is a schematic diagram of the lens structure in the telescope assembly;

[0024] FIG4 is a schematic structural diagram of a focusing module;

[0025] FIG5 is a schematic diagram of the detection height of the present invention at 100 m.

[0026] The meanings of the reference numerals in the figure are: 1. first focusing lens, 2. second focusing lens, 3. first aberration compensation lens, 4. second aberration compensation lens, 5. focusing mechanism adapter, 6. fine-tuning knob, 7. fixing sleeve, 8. fine-tuning support rod, 9. fiber optic jumper flange. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The present invention is applicable to the following scenarios.

[0029] Embodiment 1: In conjunction with Figure 2, a four-in-one telescope system for wind measurement radar includes a laser emitter, and the number of light beams emitted by the laser emitter is less than or equal to 10; the theoretical number of light beams can be increased, but due to the large rear-end focusing mechanism, it can currently only accommodate less than or equal to 7; the number of laser emitters can be continuously increased according to the continuous improvement of the rear-end focusing mechanism; the divergence angle of the light beam emitted by the laser emitter is less than 0.125, that is, NA<0.125, NA is the vertical aperture of the lens (dimensionless); an optical channel switching switch, several focusing modules, a dust protection mirror and a telescope assembly are sequentially arranged behind the laser emitter, and the telescope assembly includes several lenses and a lens barrel, and the lens barrel is made of a material with a low thermal expansion coefficient.

[0030] The lens barrel is made of low thermal expansion material, which can provide high image quality within the temperature range of -40-80℃.

[0031] Table 1 Image quality at different temperatures

[0032] 3 , the present invention achieves simultaneous control of the light beam through optical design with a large field of view, focus control in a wide temperature range, and a stress-free back-end focusing solution.

[0033] a. Optical design with large field of view

[0034] The present invention designs an optical transmission system with a 17°-20° field of view.

[0035] The lenses in the telescope assembly include a first focusing lens 1, a second focusing lens 2, a first aberration compensation lens 3 and a second aberration compensation lens 4. The first focusing lens 1 and the second focusing lens 2 are arranged near one end of the dust-proof protective lens; the first focusing lens 1 and the second focusing lens 2 converge a laser beam with a divergence angle to achieve nearly collimated light output; the image height and aberration compensation are adjusted by the first aberration compensation lens 3 and the second aberration compensation lens 4 to achieve an image quality design far less than the diffraction limit.

[0036] The distance between the first focusing lens 1 and the second focusing lens 2 is set to 0 mm-2 mm, and the distance between the second focusing lens 2 and the first aberration compensation lens 3 is set to 80 mm-100 mm.

[0037] Table 2 Different distances between the first focusing lens 1 and the second focusing lens 2 and different wavefront aberrations of the telescope assembly composed of the second focusing lens 2 and the first aberration compensation lens 3

[0038] The first focusing lens 1 and the second focusing lens 2 are both configured to have one side as a flat surface and the other side as a convex surface, and the convex surface of the first focusing lens 1 contacts the convex surface of the second focusing lens 2; both sides of the first aberration compensation lens 3 are configured to be concave surfaces, and both sides of the second aberration compensation lens 4 are configured to be convex surfaces.

[0039] b. Wide temperature far-field focus control

[0040] Combined with Figure 3, different from the traditional optical lens design concept, the lens used in wind radar needs to consider the transmission of Gaussian light in space. The actual far-field focus L' is controlled by the following formula:

[0041] l is the distance between the lens and the fiber waist, F is the focal length of the lens, and f is calculated by f=πω0 2 / λ, calculated, ω0 is the Gaussian beam waist radius, λ is the wavelength of light;

[0042] The relationship between l, F, and f at different temperatures is controlled to achieve stable focus position over a wide temperature range of -40 to 80°C.

[0043] The software calculated that the pointing direction changes by 0.04° within the temperature range of -40°C to 60°C. Within the temperature range of 10°C to 60°C, the pointing direction changes by 0.015°, a 6.3% improvement in stability, meeting the operational requirements of wind lidar.

[0044] Table 3 Stability at different temperatures and image heights

[0045] Combined with Figure 4, the rear-end focusing module is used

[0046] The focusing method uses back-end focusing because there are certain tolerances in the optical fiber divergence angle and the jumper itself. If the front-end focusing lens group is used, the signal-to-noise ratio consistency among the four channels will be poor.

[0047] The focusing module includes a focusing mechanism adapter 5, a fine-tuning knob 6, a fixed sleeve 7, a fine-tuning support rod 8 and a fiber jumper flange 9; the focusing mechanism adapter 5 is used to assemble the focusing module on the lens barrel; the fixed sleeve is arranged on one side of the focusing mechanism adapter 5, the fine-tuning knob 6 is arranged on the outside of the fixed sleeve, and the fine-tuning support rod 8 is arranged at the end of the fixed sleeve away from the focusing mechanism adapter 5, the stepping setting of the fine-tuning knob 6 is 10-100um, and the total stroke is 10-20mm; the fine-tuning knob 6 can drive the fine-tuning support rod 8 to move forward and backward; the fixed sleeve 7 is connected to the focusing mechanism adapter 5 and the fine-tuning support rod 8 to maintain high coaxiality; the fiber jumper flange 9 is arranged at the other end of the fine-tuning support rod 8, and a fiber jumper head is connected to the fiber jumper flange 9, and the fiber jumper head is set to an APC interface or a PC interface; when using the focusing module, rotating the fine-tuning knob 6 drives the optical fiber to move forward and backward to realize the control of the laser far-field focus position.

[0048] Adopt a stress-free and highly consistent installation and adjustment solution.

[0049] Because multiple beams share a common lens, focusing cannot be achieved by directly adjusting the objective lens assembly. Therefore, the laser radar's central detection position must be adjusted using rear-end fiber position adjustment. For example, a 100m measurement shows highly consistent detection capability across the four beams over a 12-hour period, as shown in Figure 5.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of protection of the present invention.

Claims

1. A four-in-one telescope system for wind radar, comprising a laser transmitter, characterized in that: An optical channel switching switch, a plurality of focusing modules, a dust protection mirror and a telescope assembly are sequentially arranged behind the laser transmitter. The telescope assembly comprises a plurality of lenses and a lens barrel. The plurality of lenses form an optical transmission system with a field of view of 17°-20°, comprising a first focusing lens (1), a second focusing lens (2), a first aberration compensation lens (3) and a second aberration compensation lens (4). The first focusing lens (1) and the second focusing lens (2) are arranged near one end of the dust protection mirror. The first focusing lens (1) and the second focusing lens (2) converge a laser beam with a divergence angle to achieve near-collimated light output. The image height and aberration compensation are adjusted by the first aberration compensation lens (3) and the second aberration compensation lens (4) to achieve an image quality design far less than the diffraction limit.

2. The four-in-one telescope system for wind radar according to claim 1, characterized in that: The number of light beams emitted by the laser emitter is less than or equal to 10.

3. The four-in-one telescope system for wind radar according to claim 1, characterized in that: The divergence angle of the light beam emitted by the laser emitter is less than 0.125, that is, NA<0.

125.

4. A four-in-one telescope system for wind radar according to any one of claims 1 to 3, characterized in that: Based on the transmission of Gaussian light in space, The distance l between the first focusing lens (1) and the beam waist is calculated, where l' is the actual far-field focus, F is the focal length of the lens, and f is calculated by f = πω0 2 / λ, calculated, ω0 is the Gaussian beam waist radius, λ is the light wavelength.

5. The four-in-one telescope system for wind radar according to claim 1, characterized in that: The distance between the first focusing lens (1) and the second focusing lens (2) is set to 0 mm-2 mm, and the distance between the second focusing lens (2) and the first aberration compensation lens (3) is set to 80 mm-100 mm.

6. The four-in-one telescope system for wind radar according to claim 5, characterized in that: The first focusing lens (1) and the second focusing lens (2) are both configured to have one side being a flat surface and one side being a convex surface, and the convex surface of the first focusing lens (1) is in contact with the convex surface of the second focusing lens (2); both sides of the first aberration compensation lens (3) are configured to be concave surfaces, and both sides of the second aberration compensation lens (4) are configured to be convex surfaces.

7. The four-in-one telescope system for wind radar according to claim 1, characterized in that: The focusing module comprises a focusing mechanism adapter (5), a fine-tuning knob (6), a fixed sleeve (7), a fine-tuning support rod (8) and a fiber jumper flange (9); the focusing mechanism adapter (5) is used to assemble the focusing module on the lens barrel; the fixed sleeve is arranged on one side of the focusing mechanism adapter (5), the fine-tuning knob (6) is arranged on the outside of the fixed sleeve, the fine-tuning support rod (8) is arranged at the end of the fixed sleeve away from the focusing mechanism adapter (5), and the fine-tuning knob (6) can drive the fine-tuning support rod (8) to move forward and backward; the fixed sleeve (7) is connected to the focusing mechanism adapter (5) and the fine-tuning support rod (8) to maintain high coaxiality; the fiber jumper flange (9) is arranged at the other end of the fine-tuning support rod (8), and the fiber jumper head is connected to the fiber jumper flange (9); when the focusing module is used, the fine-tuning knob (6) is rotated to drive the optical fiber to move forward and backward, thereby realizing the control of the laser far-field focal position.

8. The four-in-one telescope system for wind radar according to claim 7, characterized in that: The stepping setting of the fine-tuning knob (6) is 10-100um, and the total stroke is 10-20mm.

9. The four-in-one telescope system for wind radar according to claim 7, characterized in that: The optical fiber jumper head is configured as an APC interface or a PC interface.

10. The four-in-one telescope system for wind radar according to claim 1, characterized in that: The lens barrel is made of a material with a low thermal expansion rate.

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