CN111323122A - A spaceborne multi-channel aurora spectral imaging device - Google Patents

Abstract

The invention discloses a spaceborne multi-channel aurora spectral imaging device, comprising an optical lens barrel, an optical imaging system, an array interference filter, an array detector and a signal processing module, wherein the optical lens barrel is arranged in front of the optical imaging system , the array interference filter is arranged in front of the array detector and close to the array detector; the array detector is placed at the focal plane of the optical imaging system; the optical lens barrel is used to install the optical imaging system, and is also used to eliminate Stray light; the optical imaging system is used to collect the signal emitted by the detection target and focus and image it on the array detector; the array interference filter is divided into different areas to transmit light of different wavelengths to realize the detection of aurora radiation in the wavelength band The array detector is used to measure the aurora radiation focused on the array detector and convert it into an electrical signal; the signal processing module is used to read and amplify the electrical signal output by the array detector, and arrange it into a certain format as required output later.

Description

A spaceborne multi-channel aurora spectral imaging device

technical field

The invention relates to an aurora photometric measuring instrument, in particular to a spaceborne multi-channel aurora spectral imaging device.

Background technique

Aurora is a natural luminescence phenomenon produced by the interaction of space energy particles and atmospheric components. The measurement of aurora intensity and spatial distribution is of great significance for studying the coupling of solar wind-magnetosphere-middle and upper atmosphere.

In order to measure different aurora emission lines, there are generally the following common methods: one is to use a grating or prism spectrometer to obtain the required aurora emission lines through light splitting. The advantage of this method is high spectral resolution, which is especially suitable for studying the spectral characteristics of aurora; its disadvantages are large volume, large weight, poor light-gathering ability, and when used to measure isolated auroral emission lines with large wavelength distances Time efficiency is low. Another way is to use an interference filter. Although it has a large light-gathering ability, because each interference filter corresponds to a specific wavelength, it is necessary to measure multiple aurora emission lines. There are usually three solutions. , one is to use multiple independent photometers, each of which has independent interference filters, optical systems, detectors and electronic amplifiers; the other is to install multiple interference filters on a filter wheel, through Turning the filter wheel changes the wavelengths transmitted through the interference filter. Although it only uses one set of optical system, detector and electronic amplifier, it increases the rotation mechanism, reduces the reliability of the system, and can only detect different targets in time. Another common disadvantage of these two methods is still large volume and weight. The second is to use a combination of a dichroic filter and an interference filter. The dichroic filter reflects the incident light beam with a wavelength greater than (or less than) a certain wavelength, and transmits another part of the incident light beam less than (or greater than) a certain wavelength, and then passes through The interference filter selects the desired wavelength. The advantage of this method is that only one optical system is required and no rotating parts are required, but separate detectors and electronic amplifiers are still required for different detection wavelengths.

SUMMARY OF THE INVENTION

The purpose of the present invention is: in order to solve the shortcomings of the existing technology, such as the large size and weight of the instrument and the need for rotating parts when the existing technology performs spectral measurement on weak signals such as multiple aurora characteristic radiation on the satellite, provide a multi-channel interference filter for on-board multi-channel interference filters. Light Sheet Aurora Spectral Imaging Device.

In order to achieve the above object, the present invention proposes a spaceborne multi-channel aurora spectral imaging device, the device includes an optical lens barrel, an optical imaging system, an array interference filter, an array detector and a signal processing module, the optical mirror The barrel is arranged in front of the optical imaging system, the array interference filter is arranged in front of the array detector and close to the array detector; the array detector is arranged at the focal plane of the optical imaging system;

The optical lens barrel is used for installing the optical imaging system and also for eliminating stray light;

The optical imaging system is used to collect the signal emitted by the detection target, and focus and image the signal on the array detector;

The array interference filter is divided into different regions, which are used to transmit light of different wavelengths and realize the selection of aurora radiation detection bands;

the array detector for measuring the aurora radiation focused on the array detector and converting it into an electrical signal;

The signal processing module is used for reading and amplifying the electrical signals output by the array detector, and arranging them into a certain format as required and then outputting them.

As an improvement of the above device, the device further comprises: a power supply for supplying power to the whole device.

As an improvement of the above device, the parameters of the optical imaging system are determined by the detection target. If the energy of the detection target is weak, it is designed as an optical system with a large relative aperture. The angle of incidence on the surface of the array interference filter.

As an improvement of the above device, the incident angle φ of the optical imaging system is:

φ=θ+α

Among them, α is the field of view of the optical imaging system, and θ is the corresponding angle of the focal length and entrance pupil height of the optical imaging system on the surface of the interference array filter under the incident of parallel light:

Among them, f' is the focal length of the system, and h is the entrance pupil height.

As an improvement of the above device, the detection wavelength λ of the array interference filter is:

Among them, λ ₀ is the center wavelength of the array interference filter when parallel light is incident, n ₀ is the refractive index of air, and n _eff is the refractive index of the interference array filter.

As an improvement of the above device, each area of the array filter corresponds to one wavelength, and a single area can only transmit one central wavelength; when the array detector needs to detect N wavelengths, the array interference filter is A filter with N center wavelengths.

Compared with the prior art, the technical advantages of the present invention are:

1. The device of the present invention does not require rotating parts, and is small in size, light in weight, and high in stability, especially in the field of aerospace, which can better reflect its advantages;

2. The present invention proposes a new miniaturized design method for a spectroscopic instrument, which reduces the size and weight of the instrument and improves the stability on the premise of satisfying the detection target.

Description of drawings

1 is a schematic diagram of a spaceborne multi-channel aurora spectral imaging device of the present invention;

FIG. 2 is a schematic diagram of the optical path of the spaceborne multi-channel aurora spectral imaging of the present invention.

Reference number:

1. Optical imaging system 2. Array interference filter 3. Array detector

4. Signal processing module 5. Power supply 6. Optical lens barrel

7. Shell

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings

The technical scheme of the invention is as follows: an optical imaging system is used to collect the signal sent by the detection target, and then the target signal is imaged so that it can be received by the detector. An array interference filter is placed in front of the photosensitive detector. The array interference filter includes multiple channels, each channel corresponds to a central wavelength, and other wavelengths cannot pass through. This method is used to separate this wavelength from the signal. Set as many channels as you need to detect as many wavelengths of spectral information. The sub-regions of the array detector correspond to receive the optical signal transmitted through the array interference filter, and obtain the aurora radiation information of the detection target through data processing.

As shown in FIG. 1, the present invention proposes a spaceborne multi-channel aurora spectral imaging device, including an optical imaging system 1, an array interference filter 2, an array detector 3, a signal processing module 4, a power supply 5, and an optical lens barrel 6 and a housing 7 , the optical imaging system 1 , the array interference filter 2 , the array detector 3 , the signal processing module 4 , the power supply 5 and the optical lens barrel 6 are installed in the housing 7 . The shape of the housing of the device in FIG. 1 is only an example and not limiting.

The optical lens barrel 6 is placed in front of the optical imaging system for installing the optical imaging system 1 and also for eliminating stray light;

The optical imaging system 1 is used to collect the signal emitted by the detection target, and focus and image it on the array detector 3;

The parameters of the optical imaging system 1 are mainly determined by the detection target. If the energy of the detection target is weak, it is designed as an optical system with a large relative aperture. If the field of view of the detection target is large, a long focal length system is designed to reduce the interference on the surface of the array interference filter. angle of incidence.

The array interference filter 2 is placed in front of the array detector 3, close to the array detector 3, and the array interference filter 2 is divided into different regions to transmit light of different wavelengths and realize the selection of aurora radiation detection bands . Each area of the array interference filter 2 corresponds to one wavelength, and a single area can only transmit one central wavelength. The array detector needs to detect N wavelengths, so the array interference filter is a filter with N central wavelengths.

The main problem in the design is the matching of the optical system and the filter, so that the optical imaging system has as small an incident angle of light as possible in front of the detector. For the array interference filter, the incident light requires vertical incidence or approximately vertical incidence, otherwise a large center wavelength shift will occur, making the target wavelength impermeable. The relationship between the incident angle and the filter center wavelength is as shown in formula (1) shown:

Among them, φ is the incident angle, λ is the center wavelength of the filter corresponding to the incident angle φ, λ ₀ is the center wavelength of the filter at normal incidence, n ₀ is the refractive index of air, and n _eff is the filter material. refractive index.

The size of the incident angle is determined by the optical imaging system 1. Formula (2) is the change of the system focal length and entrance pupil height at the corresponding angle θ on the filter surface when parallel light is incident. Formula (3) shows that the incident angle φ is determined by The field of view angle α and θ of the system are jointly determined:

φ=θ+α (3)

Among them, f' is the focal length of the system, and h is the entrance pupil height.

Therefore, in the design, the optical imaging system 1 is designed mainly according to the requirements of the incident angle of the array interference filter 2 .

The array detector 3 is placed at the focal plane of the optical imaging system 1 to measure the aurora radiation focused on the array detector 3 after passing through the optical imaging system 1 and the array interference filter 2, and convert it into an electrical signal.

The signal processing module 4 is used to read and amplify the electrical signals output by the array detector 3, and arrange them into a certain format as required and output them.

The power supply 5 is used to power the whole device.

As shown in Figure 2, the measurement process of the entire device is:

Step 1) The optical imaging system collects the signal sent by the target, and then images the target signal;

Step 2) The received target signal is imaged on the array detector after passing through the array interference filter; the array interference filter is a filter with 4 central wavelengths;

Step 3) Receive the light information of the corresponding wavelength in the corresponding area on the array detector, and obtain the information of the detection target through data processing.

Because the device of the present invention adopts an array interference filter, the array interference filter itself is small in size. Compared with the existing spectrometer, the instrument of the present invention is greatly reduced in volume and weight, and because there are no rotating parts, the system is increased. Reliability, which is extremely important in aerospace and other fields.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention will not depart from the spirit and scope of the technical solutions of the present invention, and should be included in the present invention. within the scope of the claims.

Claims (6)

1. an on-board multi-channel aurora spectral imaging device is characterized in that, the device comprises an optical lens barrel, an optical imaging system, an array interference filter, an array detector and a signal processing module, and the optical lens barrel is arranged on the In front of the optical imaging system, the array interference filter is arranged in front of the array detector and close to the array detector; the array detector is placed at the focal plane of the optical imaging system; The optical lens barrel is used for installing the optical imaging system and also for eliminating stray light; The optical imaging system is used to collect the signal emitted by the detection target, and focus and image the signal on the array detector; The array interference filter is divided into different regions, which are used to transmit light of different wavelengths and realize the selection of aurora radiation detection bands; the array detector for measuring the aurora radiation focused on the array detector and converting it into an electrical signal; The signal processing module is used for reading and amplifying the electrical signals output by the array detector, and arranging them into a certain format as required and then outputting them. 2 . The spaceborne multi-channel aurora spectral imaging device according to claim 1 , wherein the device further comprises: a power supply for supplying power to the entire device. 3 . 3. The spaceborne multi-channel aurora spectral imaging device according to claim 1, wherein the parameters of the optical imaging system are determined by the detection target, and the detection target energy is weak, then an optical system with a large relative aperture is designed to detect If the target field of view is large, a long focal length system is designed to reduce the incident angle on the surface of the array interference filter. 4. The spaceborne multi-channel aurora spectral imaging device according to claim 1, wherein the incident angle φ of the optical imaging system is: φ=θ+α Among them, α is the field of view of the optical imaging system, and θ is the corresponding angle of the focal length and entrance pupil height of the optical imaging system on the surface of the interference array filter under the incident of parallel light:

Among them, f' is the focal length of the system, and h is the entrance pupil height. 5. The spaceborne multi-channel aurora spectral imaging device according to claim 4, wherein the detection wavelength λ of the array interference filter is:

Among them, λ ₀ is the center wavelength of the array interference filter when parallel light is incident, n ₀ is the refractive index of air, and n _eff is the refractive index of the interference array filter. 6 . The spaceborne multi-channel aurora spectral imaging device according to claim 1 , wherein each region of the array filter corresponds to one wavelength, and a single region can only transmit one central wavelength; when the array detects If the detector needs to detect N wavelengths, the array interference filter is a filter with N central wavelengths.

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