CN107367275A - A kind of high rail autonomous navigation of satellite sensor - Google Patents

Abstract

An autonomous navigation sensor for a high-orbit satellite, comprising a star field of view light shield, an earth field of view light shield, an optical system, a detection circuit, and a processing circuit. The optical system is a visible light/ultraviolet dual-spectrum common image plane optical system, which has two mutually perpendicular field of view channels, the star field of view and the earth field of view, and the visible light incident on the star field of view channel and the ultraviolet light incident on the earth field of view channel Light superposition is converged and imaged on the same image plane, and the earth's ultraviolet light is attenuated to match the imaging energy of the earth and stars. The light emitted by the optical system hits the CMOS image sensor of the detection circuit, and the detection circuit converts the light signal into a digital image and transmits the image to the processing circuit. The processing circuit processes and calculates the image to obtain the geocentric vector and the three-axis inertial attitude for satellite autonomous navigation. The invention has the functions of both the earth sensor and the star sensor, and has the characteristics of simple realization, low power consumption, light weight and high measurement accuracy.

Description

A high-orbit satellite autonomous navigation sensor

technical field

The invention relates to a satellite autonomous navigation sensor, in particular to a high-orbit satellite autonomous navigation sensor, which belongs to the technical field of satellite autonomous navigation.

Background technique

Autonomous navigation of spacecraft is the development trend of spacecraft control technology. It is of great significance in reducing the burden of ground measurement and control, reducing the operating cost of spacecraft, and improving the survivability of spacecraft. The most widely used and researched optical navigation is the navigation method of infrared earth sensor plus star sensor. However, the measurement accuracy of the traditional infrared earth sensor is low, which directly affects the orbit determination accuracy of the spacecraft. In addition, there are structural deformations and installation deviations between the two sensors that affect the measurement accuracy.

At present, in the prior art, some sensors use a circular field of view to image the edge of the earth, and the circular field of view is divided into multiple sub-fields of view to detect the edge of the earth. Moreover, the sensor images the earth and the stars to different areas on the detector, which is only suitable for low- and medium-orbit satellites, not high-orbit satellites.

In addition, using the navigation sensor of the earth's ultraviolet spectrum and the star's visible spectrum, the sensor uses two independent optical lenses for the earth's field of view and the star's field of view, and uses a CCD image sensor as a detector, and the earth and stars Image to different areas on the detector respectively. This kind of navigation sensor uses two optical lenses to image the earth and the stars respectively, and uses a CCD image sensor as the detector, which is not conducive to the miniaturization and low power consumption design of the product.

There are also some sensors that use a single-spectrum single-optical lens to detect stars and the earth at the same time, and it is also mentioned that a dual-spectrum dual-optical lens can be used to detect stars and the earth separately. Adopting the dual-band dual-optical lens solution is not conducive to the miniaturization design of the product. If a single ultraviolet spectrum optical lens is used to image the earth and stars at the same time, due to the low quantum efficiency of the image sensor in the ultraviolet spectrum and the weak energy of the stars, it will bring difficulties to the design. If a single visible spectrum optical lens is used to image the earth and the stars at the same time, due to the influence of the earth's atmosphere, the accuracy of the earth's measurement will be reduced.

Contents of the invention

The technical problem solved by the present invention is: to overcome the deficiencies in the prior art, to provide a high-orbit satellite autonomous navigation sensor, which can detect the earth's ultraviolet light and star visible light at the same time, output the geocentric vector and three-axis inertial attitude, and have both the earth's The function of the sensor and the star sensor, and the realization is simple, the power consumption is low, and the precision is high.

The technical solution of the present invention is: a high-orbit satellite autonomous navigation sensor, including: a star field of view light shield, an earth field of view light shield, an optical system, a detection circuit, and a processing circuit; the optical system is a dual-spectrum visible light/ultraviolet light The section common image plane optical system has two mutually perpendicular viewing channels of the star viewing field and the earth viewing field. The ultraviolet light incident on the earth's field of view channel is superimposed and converged on the same image plane, and the light emitted by the optical system is sent to the detection circuit; the detection circuit receives the optical signal emitted by the optical system, and the detection circuit converts the optical signal into a digital image and digital The image is transmitted to the processing circuit; the processing circuit processes and calculates the digital image transmitted by the detection circuit, and obtains the geocentric vector and three-axis inertial attitude of the sensor for autonomous satellite navigation; the star field of view hood and the earth field of view hood They are respectively installed on the star field of view of the optical system and the earth field of view channel of the optical system, and are used to suppress stray light from the sun and the moon from entering the optical system.

The optical system includes an ultraviolet filter and an attenuation sheet, a beam splitter, and a converging lens; the ultraviolet filter and the attenuation sheet are located at the entrance of the earth's field of view in the optical system, perpendicular to the optical axis of the earth's field of view, and filter out the earth's ultraviolet band other light, and attenuate the energy of ultraviolet light; the beam splitter is located behind the ultraviolet filter and the attenuation plate, and the angle with the optical axis of the earth's field of view is °; the converging lens is located at the rear end of the beam splitter, perpendicular to the optical axis of the star field of view; The light emitted by the stars enters the converging lens after being transmitted by the beam splitter, and the beam splitter filters out other light rays other than the visible light of the stars at the same time; Enter the converging lens; the visible light of stars and the ultraviolet light of the earth are superimposed and imaged on the same image plane after passing through the converging lens.

The detection circuit includes a CMOS image sensor and an interface driver module, the CMOS image sensor is located on the image plane of the light exit end of the optical system, converts the light signal into a digital image and sends it to the interface driver module; the interface driver module converts the image sent by the CMOS image sensor The signal is sent to a processing circuit.

The processing circuit includes an FPGA module, 2 image SRAM modules, and a processor module; the FPGA module receives the image output by the detection circuit, and stores the image in two image SRAM modules at the same time, and the FPGA module reads one of the image SRAM modules The image data of the sensor is transmitted to an external device; the processor module reads the image data in another image SRAM module for processing, and obtains the geocentric vector and three-axis inertial attitude of the sensor.

The stellar field of view of the optical system ranges from 30° to 40°.

The star detection spectral segment of the stellar field of view of the optical system adopts the visible spectral segment of 500nm-800nm.

The value range of the earth field of view of the optical system is 30°-40°.

The earth detection spectral band of the earth field of view of the optical system adopts the ultraviolet spectral band of 350nm-360nm.

The attenuation of the ultraviolet light energy of the earth by the ultraviolet filter and the attenuation sheet is 98.5% to 99.5%.

Compared with the prior art, the present invention has the following advantages:

(1) The autonomous navigation sensor proposed by the present invention can output the geocentric vector and the three-axis inertial attitude simultaneously, and has the functions of the earth sensor and the star sensor concurrently. Compared with the navigation mode of the traditional earth sensor plus the star sensor, Light weight, low power consumption, high precision.

(2) The present invention adopts a novel double-field-of-view dual-spectrum common-image plane optical system, which realizes simultaneous imaging of the earth and stars by a single optical system. This realization method has a simple structure and is conducive to product miniaturization.

(3) The present invention chooses to detect the earth's ultraviolet spectrum and the visible spectrum of stars. Because the edge of the earth's ultraviolet spectrum is stable, it is beneficial to improve the measurement accuracy, and the image sensor has high quantum efficiency in the visible spectrum, which is conducive to improving the detection sensitivity of faint stars. .

Description of drawings

Fig. 1 is a composition principle block diagram of the present invention;

Fig. 2 is a schematic circuit block diagram and an information flow diagram of the present invention;

Fig. 3 is an image processing flow chart of the present invention.

detailed description

As shown in FIG. 1 , a high-orbit satellite autonomous navigation sensor includes a star field of view light shield 1 , an earth field of view light shield 2 , an optical system 3 , a detection circuit 4 , and a processing circuit 5 . Optical system 3 is a visible light/ultraviolet dual-spectrum common-image plane optical system, which has two mutually perpendicular viewing channels of the star field of view and the earth's field of view. The ultraviolet light incident on the channel is superimposed and converged to be imaged on the same image plane, and the earth's ultraviolet light is attenuated to match the imaging energy of the earth and stars. The light emitted by the optical system 3 hits the CMOS image sensor of the detection circuit 4 , and the detection circuit 4 converts the light signal into a digital image and transmits the image to the processing circuit 5 . The processing circuit 5 processes the image and calculates the geocentric vector and three-axis inertial attitude of the sensor for autonomous satellite navigation. The stellar field of view light shield 1 is installed on the stellar field of view channel of the optical system 3 , and the earth field of view light shield 2 is installed on the earth field of view channel of the optical system 3 to prevent stray light from the sun and the moon from entering the optical system 3 .

The stellar field of view and the earth's field of view of the high-orbit satellite autonomous navigation sensor are 30°-40°, and the typical value is 38°; UV spectrum. The light energy in the earth's ultraviolet spectrum is attenuated by 98.5% to 99.5%.

Optical system 3 includes ultraviolet filter and attenuation sheet 6, spectroscope 7, converging lens 8, and wherein ultraviolet filter and attenuation sheet 6 are positioned at the entrance end of optical system 3 earth field of view, perpendicular to the optical axis of earth field of view, can filter Other light rays except the earth's ultraviolet band, and the energy attenuation of ultraviolet light. The beam splitter 7 is located behind the ultraviolet filter and the attenuation sheet 6, and is installed at an angle of 45° to the optical axis of the field of view of the earth. The converging lens 8 is located at the rear end of the beam splitter 7 and is perpendicular to the optical axis of the stellar field of view. The light emitted by the star enters the converging lens 8 after being transmitted by the beam splitter 7, and the beam splitter 7 can filter out other light rays other than the visible light of the star at the same time. The light emitted by the earth is irradiated on the beam splitter 7 after passing through the ultraviolet filter and the attenuation film 6 , and enters the converging lens 8 after being reflected by the beam splitter 7 . The visible light of the star and the ultraviolet light of the earth are superimposed and imaged on the same image plane after passing through the converging lens 8 .

As shown in Figure 2, the detection circuit 4 includes a CMOS (Complementary Metal Oxide Semiconductor) image sensor and an interface driver module, wherein the CMOS image sensor is located on the image plane of the light output end of the optical system 3, converts the optical signal into a digital image, and the interface driver The module sends the image signal to the processing circuit 5 . The processing circuit 5 includes an FPGA module, an image SRAM_a module (SRAM represents a static random access memory), an image SRAM_b module, and a processor module. The FPGA module receives the image output by the detection circuit 4, and stores the image into the image SRAM_a module and the image SRAM_b at the same time. In the module, after the image storage is completed, the processor reads out the image in the image SRAM_a module for processing, and the FPGA module reads out the image in the image SRAM_b module for downloading.

The image obtained by the autonomous navigation sensor of the high-orbit satellite is a mixed image containing the earth surface target and the star point target. Some star points fall on the earth target, and this part of the star point is an invalid star point. During image processing, the edge point of the earth is extracted first, and the geocentric vector of the sensor is obtained by fitting calculation of the edge point of the earth. The area occupied by the earth is determined by the uppermost, lowermost, leftmost, and rightmost edge points of the earth in the image, and the three-axis inertial attitude of the sensor is obtained by performing star point extraction, star map recognition, and attitude calculation on the area outside the earth in the image . The image processing flow is shown in Figure 3.

The high-orbit satellite autonomous navigation sensor realizes the detection of earth targets and stars above magnitude 5.5. The inertial attitude measurement accuracy is 8″, the geocentric vector measurement accuracy is 0.02°, and the autonomous navigation orbit determination accuracy is better than 5km.

The content not described in detail in the present invention is well known to those skilled in the art.

Claims (9)

1. A high-orbit satellite autonomous navigation sensor is characterized in that it comprises: star field of view light shield (1), earth field of view light shield (2), optical system (3), detection circuit (4), processing circuit (5); the optical system (3) is a visible light/ultraviolet dual-spectrum common-image plane optical system, which has two mutually perpendicular field of view channels, the star field of view and the earth field of view, and the optical system (3) carries out the ultraviolet light of the earth The attenuation realizes the matching of the imaging energy of the earth and the stars, and superimposes and converges the visible light incident on the channel of the stellar field of view and the ultraviolet light incident on the channel of the earth's field of view on the same image plane, and the light emitted by the optical system (3) reaches the detection circuit (4 ); the detection circuit (4) receives the optical signal emitted by the optical system (3), and the detection circuit (4) converts the optical signal into a digital image and transmits the digital image to the processing circuit (5); the processing circuit (5) detects The digital image transmitted by the circuit (4) is processed and calculated to obtain the geocentric vector and three-axis inertial attitude of the sensor for autonomous satellite navigation; the star field of view light shield (1) and the earth field of view light shield (2) are respectively It is installed on the optical system (3) star field of view and the optical system (3) earth field of view channel, and is used to suppress the stray light from the sun and the moon from entering the optical system (3). 2. A kind of high orbit satellite autonomous navigation sensor according to claim 1, is characterized in that: described optical system (3) comprises ultraviolet filter and attenuation sheet (6), beam splitter (7), converging lens (8); The ultraviolet filter and the attenuation sheet (6) are located at the entrance of the optical system (3) the earth's field of view, perpendicular to the optical axis of the earth's field of view, filter out other light rays outside the earth's ultraviolet band, and perform energy on the ultraviolet light Attenuation; the beam splitter (7) is located behind the ultraviolet filter and the attenuation plate (6), and the angle with the optical axis of the field of view of the earth is 45°; the converging lens (8) is located at the rear end of the beam splitter (7), and is connected to the star field The optical axis is vertical; the light emitted by the star enters the converging lens (8) after being transmitted through the beam splitter (7), and the beam splitter (7) filters out other light rays other than the visible light of the star at the same time; the light emitted by the earth passes through the ultraviolet filter and attenuates After being irradiated on the beam splitter (7) by the sheet (6), it is reflected by the beam splitter (7) and then enters the converging lens (8); the visible light of stars and the earth's ultraviolet light are superimposed and imaged on the same image plane after being passed through the converging lens (8) . 3. According to claim 1 or 2, a high-orbit satellite autonomous navigation sensor is characterized in that: the detection circuit (4) includes a CMOS image sensor and an interface driver module, and the CMOS image sensor is located in the optical system (3) light On the image plane at the exit end, the optical signal is converted into a digital image and sent to the interface driving module; the interface driving module sends the image signal sent by the CMOS image sensor to the processing circuit (5). 4. according to the described a kind of high-orbit satellite autonomous navigation sensor of claim 3, it is characterized in that: described processing circuit (5) comprises FPGA module, 2 image SRAM modules, processor module; FPGA module receives detection circuit (4 ) output image, and store the image in two image SRAM modules at the same time, the FPGA module reads the image data in one image SRAM module and transmits it to the external device; the processor module reads the image data in the other image SRAM module Perform processing to obtain the geocentric vector and three-axis inertial attitude of the sensor. 5. A high-orbit satellite autonomous navigation sensor according to claim 1 or 2, characterized in that: the range of the stellar field of view of the optical system (3) is 30° to 40°. 6 . A high-orbit satellite autonomous navigation sensor according to claim 5 , characterized in that: the star detection spectrum of the optical system ( 3 ) stellar field of view adopts the visible spectrum of 500nm to 800nm. 7 . 7. A high-orbit satellite autonomous navigation sensor according to claim 6, characterized in that: the field of view of the earth of the optical system (3) ranges from 30° to 40°. 8. A high-orbit satellite autonomous navigation sensor according to claim 6 or 7, characterized in that: the earth detection spectrum of the optical system (3) earth field of view adopts the ultraviolet spectrum of 350nm to 360nm. 9. A high-orbit satellite autonomous navigation sensor according to claim 2, characterized in that: the attenuation of the ultraviolet light energy of the earth by the ultraviolet filter and the attenuation sheet (6) is 98.5% to 99.5%.