CN206411264U - It is a kind of to be used for the optical axis monitoring device of the main passive detection system of high accuracy - Google Patents

Abstract

This patent discloses an optical axis monitoring device for a high-precision active and passive detection system. The device includes a laser emitting system, an optical axis separation component, a shared telescope, an optical axis monitoring camera, a passive imaging system and a laser receiving system. The utility model utilizes the characteristic that the angle between the incident and outgoing light of the prism in the incident plane is only related to the angle of the reflection surface of the prism, and introduces optical axis separation components and optical axis monitoring cameras into the high-precision multi-optical axis active and passive composite detection system. Establish the relative relationship between the optical axis of the laser emission and the optical axis of the passive imaging system, which facilitates real-time monitoring of the changes of each optical axis during the working process of the high-precision active and passive detection system, and the obtained optical axis change data can also be used in the follow-up The probe data is corrected during data processing. This patent has the advantages of high optical axis monitoring sensitivity, good optical axis stability, mature processing and adjustment technology, etc., and can be widely used in airborne and spaceborne high-precision active and passive composite detection photoelectric systems.

Description

An optical axis monitoring device for high-precision active and passive detection systems

Technical field:

This patent belongs to the technical field of active-passive composite photoelectric detection, and relates to a composite detection system that combines high-precision laser active detection/passive photoelectric imaging for airborne and space-borne platforms, especially a high-precision active-passive detection system that can be used Optical axis monitoring device.

Background technique:

As users have higher and higher requirements for the accuracy of laser surveying and mapping data, it is difficult to meet the requirements of high-precision surveying and mapping because the data obtained by relying on a single laser radar surveying and mapping system cannot be accurately matched with ground targets. In order to solve the problem of positioning the laser beam emitted by the laser radar surveying and mapping system to achieve high-precision matching between the laser beam and the ground target, the United States has adopted a high-precision attitude positioning device in the high-precision laser radar surveying and mapping system such as the Earth Laser Altimetry System (GLAS) developed by it. Combined with a large number of ground calibration control points, this not only causes the complexity of the laser mapping system itself and the ground calibration system, but also lacks real-time performance, which reduces the efficiency of the laser mapping system.

A feasible solution to solve the problem of real-time matching between the emitted laser beam and the ground scene in the laser radar mapping system is an active-passive composite detection system that combines the laser active detection system with the traditional passive imaging photoelectric system. The relative matching relationship between the optical axes of the passive imaging system can realize the precise matching of the emitted laser beam and the ground scene. However, in the actual working process, due to factors such as external vibration, gravity deformation, and environmental temperature changes, the relative relationship between the optical axis of the laser emitting system and the optical axis of the passive imaging system may change, thereby affecting the relationship between the emitted laser beam and the ground scenery. matching accuracy. In the patent of Jia Jianjun et al., they proposed a scheme for self-calibration of the optical axis by using corner cube reflection in laser quantum communication (patent number CN 102185659 B), which can only stabilize the small-scale optical axis of the subsequent optical path It can only be used in the case of the common optical path of the laser transmitting and receiving systems, and cannot monitor the changes of the optical axis of the transceiver system and the optical axis of the telescope itself.

Invention content:

In order to solve the problem of real-time monitoring of the relative relationship between the laser emission optical axis and the optical axis of the passive imaging system in the high-precision multi-optical axis active-passive composite detection system, this patent proposes an optical axis monitoring for high-precision active-passive detection system The device establishes the relative relationship between the optical axis of the laser emission and the optical axis of the passive imaging system by introducing optical axis separation components and optical axis monitoring cameras into the system, which facilitates real-time monitoring of each optical axis during the working process of the high-precision active and passive detection system. Axis changes are monitored.

The technical solution adopted in this patent is: an optical axis monitoring method and device for a high-precision active and passive detection system, which consists of a laser emitting system 1, an optical axis separation component 2, a shared telescope 3, a color separation film 4, and a passive imaging system 5. It is composed of a laser receiving system 6 and an optical axis monitoring camera 7. The laser beam emitted by the laser emitting system 1 is divided into two beams by the incident mirror 2-1 of the optical axis separation component 2, wherein the detection beam 1-1 hits the ground target after being transmitted, and the echo signal is diffusely reflected by the target. After being received by the shared telescope 3, it passes through the color separation film 4 and enters the laser receiving system 6. At the same time, the signal radiated by the ground target itself is collected by the shared telescope 3, reflected by the color separation film 4, and enters the passive imaging system 5 for imaging. The optical axis monitoring light beam 1-2 is reflected by the front and rear surfaces of the exit mirror 2-2 of the optical axis separation component 2 to form the telescope optical axis monitoring light beam 1-3 and the imaging optical axis monitoring light beam 1-4 to enter the common telescope 3, respectively Shaft monitoring camera 7 and passive imaging system 5 receive.

The laser beam emitted by the laser emitting system 1 is refracted by the optical axis separation component 2, and the telescope optical axis monitoring beam 1-3 formed by the optical axis monitoring camera 7 is received by the optical axis monitoring camera 7, and the formed spot is used to monitor the laser emitting system 1 and the common The optical axis of the telescope 3 changes, and the imaging optical axis monitoring beams 1-4 are received by the passive imaging system 5, and the formed light spots are used to monitor the relative change of the optical axis between the laser emitting system 1, the shared telescope 3 and the passive imaging system 5.

The optical axis of the detection beam 1-1 of the laser emitting system 1 after the incident mirror 2-1 forms an angle θ with the optical axis of the shared telescope 3, and the shared telescope 3 is a passive imaging system 5, a laser receiving system 6 and optical axis monitoring The shared optical path part of the camera 7, wherein the optical axis of the optical axis monitoring camera 7 coincides with the optical axis of the shared telescope 3, the optical axes of the passive imaging system 5 and the laser receiving system 6 form an angle θ with the optical axis of the shared telescope 3, and the passive imaging The optical paths of system 5 and laser receiving system 6 are separated by color separation film 4;

The optical axis separation assembly 2 is composed of an entrance mirror 2-1, an exit mirror 2-2 and a structural frame 2-3, and the entrance mirror 2-1 and the exit mirror 2-2 are installed on an integrated structural frame 2-3 Inside, the material of the structural frame 2-3 can be titanium alloy, Invar or other materials with a thermal expansion coefficient less than 10 ^-5 /°C, where the front surface normals of the incident mirror 2-1 and the exit mirror 2-2 are the same as the common telescope 3 The optical axes of are respectively 45° and -45°, and the rear surface of the incident mirror 2-1 has a wedge angle ω1 relative to the front surface, which satisfies the following relationship:

Where n is the refractive index of the material of the incident mirror (2-1), I and I' are the incident angle and refraction angle of the light beam on the front surface respectively, and the unit is angle.

The rear surface of the exit mirror 2-2 has a wedge angle ω2 relative to the front surface, which satisfies the following relationship:

n·sin(I'+2ω ₂ )=sin(I+θ), sin I=n·sin I'

Where n is the refractive index of the material of the exit mirror 2-2, I and I' are the incident angle and refraction angle of the light beam on the front surface, respectively, and the unit is angle.

The incident mirror 2 - 1 in the optical axis separation assembly 2 is located in the emitting light path of the laser emitting system 1 , and the outgoing mirror 2 - 2 is located in the receiving aperture range of the common telescope 3 .

The front surface of the incident mirror 2-1 in the optical axis separation component 2 is coated with a spectroscopic film, the rear surface is coated with an anti-reflection coating corresponding to the wavelength of the laser emission system, the front surface of the exit mirror 2-2 is coated with a spectroscopic film, and the rear surface is coated with a corresponding laser An internal reflective coating that emits at the system wavelength.

In the described optical axis monitoring method, the amount of optical axis variation can be calculated as follows: Let a ₁ and a ₂ be the light spot offsets detected on the detectors of the optical axis monitoring camera 7 and the passive imaging system 5 respectively, f ₁ and a 2 f ₂ are the focal lengths of the precisely calibrated optical axis monitoring camera 7 and the passive imaging system 5 respectively, and the corresponding optical axis changes are respectively:

pass with The relationship between the size and direction can be used to analyze and judge the change of the optical axis of the system.

The advantage of this patent is that: the relative relationship between the laser emission optical axis and the passive imaging system optical axis is established in the high-precision multi-optical axis active-passive composite detection system, which can realize real-time detection during the working process of the high-precision active-passive detection system Monitoring the changes of each optical axis has the characteristics of high optical axis monitoring sensitivity, good optical axis stability, and mature processing and assembly technology. It can be widely used in airborne and spaceborne high-precision active-passive composite detection photoelectric systems.

Description of drawings:

Fig. 1 is a schematic diagram of the optical path of the optical axis monitoring device.

Fig. 2 is a schematic diagram of the total optical path of the optical system in the embodiment.

Fig. 3 is a three-dimensional isometric view of the optical axis separation assembly in the embodiment.

Fig. 4 is an optical path diagram of the incident mirror 2-1 of the optical axis splitting assembly in the embodiment.

Fig. 5 is an optical path diagram of the exit mirror 2-2 of the optical axis splitting assembly in the embodiment.

detailed description:

Below in conjunction with accompanying drawing and embodiment the technical scheme of this patent is described further:

As shown in Figure 2, this embodiment describes a dual-beam laser altimeter optical system design that uses this patent to image laser footprints, including a shared telescope, visible/near-infrared color separation film, passive imaging camera, laser receiving system, optical axis monitoring camera, optical axis separation component and laser emitting system. The system consists of two sets of identical components that are distributed axisymmetrically with the optical axis of the shared telescope as the symmetrical axis. The passive imaging camera, laser receiving system and optical axis monitoring camera share the afocal telescope, and the passive imaging camera and laser receiving system utilize the optical axis of the shared telescope. The off-axis field of view, the optical axis monitoring camera uses the on-axis field of view of the shared telescope, the passive imaging camera and the laser receiving system separate the optical path through the visible/near-infrared color separation film, two sets of optical axis separation components and the laser emitting system are located in the optical path of the telescope On both sides, the optical axes thereof are respectively parallel to the optical axes of the two sets of passive imaging cameras. The laser beam emitted by the laser emission system is divided into two beams by the incident mirror of the optical axis separation component. After the detection laser is transmitted, it hits the ground target. After being diffusely reflected by the ground target, the echo signal is received by the shared telescope and transmitted through the visible/near infrared spectrum. The color film enters the laser receiving system, and the visible light signal radiated by the ground target itself is also collected by the shared telescope, and after being reflected by the visible/near-infrared color separation film, it enters the passive imaging camera for imaging. The optical axis monitoring laser is reflected by the exit mirror of the optical axis separation component to form the telescope optical axis monitoring laser and the imaging optical axis monitoring laser, which are incident to the common telescope and received by the passive imaging camera and the optical axis monitoring camera respectively.

The system parameters of the shared telescope, passive imaging camera, laser receiving system and optical axis monitoring camera in this embodiment are shown in the table below.

The integrated structural frame in this embodiment is shown in Figure 3, and the material used is Invar.

In this embodiment, θ=0.7°, and the internal optical path diagrams of the incident mirror and the outgoing mirror of the optical axis splitting assembly are shown in Fig. 4 and Fig. 5 respectively. The wedge angle between the rear surface and the front surface of the incident mirror ω1=0.88°, the wedge angle between the rear surface and the front surface of the exit mirror is ω2=0.19°, the material of the entrance mirror and the exit mirror are both fused silica, at 1064nm The refractive index of 1.45.

In this embodiment, the detector pixel size of the passive imaging camera and the optical axis monitoring camera is 6um, and the focal length is 2600mm. When the light spot is shifted by one pixel on the detector, the optical axis stability monitoring sensitivity is If the spot centroid algorithm is used to subdivide the pixels, the sensitivity can be further improved.

Claims (5)

1. An optical axis monitoring device for high-precision active and passive detection systems, mainly including a laser emitting system (1), an optical axis separation component (2), a shared telescope (3), a color separation film (4), and a passive imaging System (5), laser receiving system (6) and optical axis monitoring camera (7) part, it is characterized in that: The incident mirror (2-1) in the optical axis separation assembly (2) is located in the emitting light path of the laser emitting system (1), and the outgoing mirror (2-2) is located within the receiving aperture range of the shared telescope (3); The optical axis of the detection beam (1-1) after the laser beam emitted by the described laser emitting system (1) passes through the incident mirror (2-1) forms an angle θ with the optical axis of the shared telescope (3), and θ is not For an angle value less than 0.5°, the shared telescope (3) is a part of the shared optical path of the passive imaging system (5), the laser receiving system (6) and the optical axis monitoring camera (7), wherein the optical axis of the optical axis monitoring camera (7) and The optical axis of shared telescope (3) coincides, and the optical axis of passive imaging system (5) and laser receiving system (6) forms θ angle with the optical axis of shared telescope (3), and passive imaging system (5) and laser receiving system ( 6) The light path is separated by the color separation film (4); The laser beam emitted by the laser emitting system (1) is divided into two beams by the incident mirror (2-1) of the optical axis separation component (2), wherein the detection beam (1-1) hits the ground target after being transmitted, and is After the diffuse reflection of the target, the echo signal is received by the shared telescope (3) and enters the laser receiving system (6) through the color separation film (4). (4) Enter the passive imaging system (5) for imaging after reflection; the optical axis monitoring beam (1-2) is reflected by the front and rear surfaces of the exit mirror (2-2) of the optical axis separation component (2) to form the telescope optical axis monitoring beam ( 1-3) and the imaging optical axis monitoring light beam (1-4) are incident on the shared telescope (3), and are respectively received by the optical axis monitoring camera (7) and the passive imaging system (5). 2. An optical axis monitoring device for high-precision active and passive detection systems according to claim 1, characterized in that: the laser beam emitted by the laser emitting system (1) is deflected by the optical axis separation component (2) The formed telescope optical axis monitoring beam (1-3) is received by the optical axis monitoring camera (7), and the formed spot is used to monitor the optical axis change between the laser emitting system (1) and the shared telescope (3), and the imaging optical axis The monitoring light beams (1-4) are received by the passive imaging system (5), and the formed light spots are used to monitor the relative change of the optical axis between the laser emitting system (1), the shared telescope (3) and the passive imaging system (5). 3. The optical axis monitoring device for high-precision active and passive detection systems according to claim 1, characterized in that: the optical axis separation assembly (2) consists of an entrance mirror (2-1), an exit mirror (2-2) and a structural frame (2-3), the incident mirror (2-1) and the outgoing mirror (2-2) are installed in an integrated structural frame (2-3), and the structural frame (2- 3) The material can be titanium alloy, Invar or other materials with a thermal expansion coefficient less than 10 ^-5 /°C, where the front surface normal of the incident mirror (2-1) and the exit mirror (2-2) is the same as the common telescope (3 ) are respectively 45° and -45°, and the rear surface of the incident mirror (2-1) has a wedge angle ω ₁ relative to the front surface, which satisfies the following relationship: Wherein n is incident mirror (2-1) material refractive index, and I and I ' are respectively incident angle and refraction angle of light beam at front surface, and unit is angle, and θ is the angular value described in claim 1; The rear surface of the exit mirror (2-2) has a wedge angle ω ₂ relative to the front surface, which satisfies the following relationship: n·sin(I'+2ω ₂ )=sin(I+θ), sin I=n·sin I' Wherein n is the material refractive index of the exit mirror (2-2), I and I ' are respectively the incident angle and the refraction angle of the light beam at the front surface, and the unit is angle, and θ is the angle value described in claim 1. 4. A kind of optical axis monitoring device for a high-precision active and passive detection system according to claim 1, characterized in that: the front surface of the entrance mirror (2-1) is coated with a spectroscopic film, and the rear surface is coated with a corresponding laser AR coating for emitting system wavelengths. 5. A kind of optical axis monitoring device for high-precision active and passive detection systems according to claim 1, characterized in that: the front surface of the exit mirror (2-2) is coated with a spectroscopic film, and the rear surface is coated with a corresponding laser An internal reflective coating that emits at the system wavelength.