CN101915924A - A Room Temperature Infrared Inner Satellite Imaging Detector - Google Patents

Abstract

The invention discloses a normal-temperature infrared inner satellite imaging detector, which is suitable for detecting inner satellites and belongs to the technical fields of spacecraft systems and measuring instruments. In order to realize the detection of satellites in a closed small-sized space, the invention provides an infrared imaging detector system based on the far-infrared band, which consists of a short focal length lens, an uncooled infrared focal plane array, a data acquisition circuit and an image data processing unit composition. The short-focus lens is suitable for imaging objects at a distance of 100mm-500mm in the 8-12um band. The uncooled infrared focal plane array works in the far infrared band and can sense heat sources at room temperature. The invention can realize the infrared imaging of the moving object in the space-borne small-sized closed environment without relying on the external light source and the temperature reference sheet.

Description

A Room Temperature Infrared Inner Satellite Imaging Detector

technical field

The invention belongs to the technical field of spacecraft systems and infrared measurement, and in particular relates to a detector for imaging by using far-infrared radiation naturally emitted by inner satellites in a normal temperature environment.

Background technique

The inner formation satellite system is a way of gravitational field measurement, and the real-time and accurate measurement of the relative positions of the inner satellite and the outer satellite is one of the keys to realize the inner formation mission.

Infrared measurement methods are a viable means of relative position measurement. DeHoff RL of Stanford University in 1975 doctoral dissertation "Minimum thrusters control of a spinning drag-free satellite, including the design of a largecavity optical sensor Design)” proposed to use ultraviolet light to excite the phosphorus coating on the proof mass (the aforementioned inner satellite is also a proof mass), and use the fence diode to receive the emitted infrared rays to determine the position of the proof mass, with an accuracy of mm. This method uses infrared light in the short infrared range. The inner formation system works at room temperature (300K), and the emitted infrared rays are mainly distributed in the far-infrared band of 8-12 μm, so the above-mentioned detection methods are not applicable.

The application of infrared detection system on spacecraft includes meteorological satellites, environmental survey, military reconnaissance, astronomical observation, etc. Gong Haimei published "The Development Status and Progress of Aerospace Infrared Detectors" in "Infrared and Laser Engineering" in 2008. In summary, it is pointed out that most of the current aerospace infrared detectors use low-temperature refrigeration design, and the working temperature is 70-200K. Since the radiometer effect caused by the large temperature difference needs to be avoided in the internal formation mission, the cooled detector is not suitable. Uncooled detectors are rarely used on spacecraft, and their working wavelengths are all in the very long wave band above 15 μm. In addition, the requirements for infrared detection of inner formation missions include: large viewing angle, short depth of field, and fixed signal-to-noise ratio of the detector within a small dynamic range; this is different from the small field of view, long depth of field, and large Dynamic range and variable SNR are very different.

Although the current general-purpose thermal imager products working in the long infrared band are relatively mature, their volume, power consumption and weight are too large due to their versatility, which is far from meeting the needs of internal formation tasks for embedded design.

Contents of the invention

The object of the present invention is to provide a normal temperature infrared inner satellite imaging detector which can detect the relative position of the inner satellite by utilizing the far infrared radiation imaging naturally emitted by the inner satellite at normal temperature.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

The room-temperature infrared inner satellite imaging detector of the present invention includes a near-focus far-infrared lens, a far-infrared band focal plane array and an image data sampling circuit, and the combination of the near-focus far-infrared lens and the far-infrared band focal plane array forms a lens- The focal plane array unit, the image data sampling circuit and the image data processing unit are connected and combined to form a circuit unit, the image data sampling circuit in the circuit unit and the far-infrared band focal plane array in the lens-focal plane array unit pass through cable connection.

Preferably, the lens and the focal plane array unit are installed in a housing, and the housing is closed with blackened aluminum metal on the inner surface except for the rear cable interface.

Preferably, an aviation joint is connected between the far-infrared focal plane array and the cable, the surrounding of the aviation joint 4 is sealed with silica gel, and the depth L of the silica gel is greater than 3 times the opening size D.

Preferably, the near-focus far-infrared lens adopts a fixed-focus lens with an angle of view of more than 90 degrees and a depth of field of 100-500 mm, and the relative distance from the far-infrared band focal plane array is fixed.

Preferably, it is characterized in that: the far-infrared band focal plane array is an uncooled infrared focal plane array working in the far-infrared band.

Preferably, the image data sampling circuit is composed of a timing generation unit, an AD sampling unit, and a reference voltage array, and the CPLD generates the timing required for the far-infrared band focal plane array imaging and the differential input AD sampling unit, and the The reference voltage array produces the reference voltage required by the far-infrared band focal plane array and the common-mode voltage and reference voltage required by the differential input AD sampling unit, and the AD sampling unit is connected to the far-infrared band focal plane array planar array.

More preferably, the timing generating unit adopts a CPLD with less than 300,000 gates, and the reference voltage array is composed of a low-temperature drift linear power supply chip connected to a high-precision resistor. The low-temperature drift linear power supply chip is an adjustable power supply chip with a temperature drift not greater than 100ppm/°C, and the high-precision resistor is a 1% precision resistor.

More preferably, a signal conditioning circuit is connected between the analog signal output terminal of the infrared focal plane array and the AD sampling unit, and the signal conditioning circuit has a fixed gain and a fixed voltage bias. The common-mode voltage and the gain of the signal conditioning circuit are selected according to the following method: the amplitude range of the effective output signal of the room-temperature infrared inner satellite imaging detector matches the input range of the AD sampling unit.

The beneficial effects of the present invention are as follows:

The room-temperature infrared inner satellite imaging detector of the present invention, aiming at the low temperature difference between the foreground and the background in the inner satellite detection technology, realizes the coordination of the imaging gray scale range and the sampling extreme value window through the precise setting of the resistance value, and maximizes the Imaging contrast is improved, clear detection is realized, and the detector of the present invention does not need a focusing mechanism, which simplifies the system complexity of the detector. The focal plane array and the circuit are connected through cables, and there is distance division, which is beneficial to suppress the forward electromagnetic radiation.

Description of drawings

Fig. 1 is the structural representation of satellite imaging detector in normal temperature infrared of the present invention;

Fig. 2 is a functional block diagram of the image data sampling circuit in the room temperature infrared inner satellite imaging detector of the present invention.

Detailed ways

The room temperature infrared inner satellite imaging detector of the present invention will be further described below in conjunction with examples and accompanying drawings. FIG. 1 shows a schematic structural diagram of the room temperature infrared inner satellite imaging detector of the present invention, and FIG. 2 shows a functional block diagram of an image data sampling circuit of the present invention.

Referring to accompanying drawing 1, close-focus far-infrared lens 1 and far-infrared band focal plane array 2 in the room temperature infrared satellite imaging detector of the present invention are combined together to form lens-focal plane array unit, and in described far-infrared band focal plane array unit, An aviation connector 4 is connected to the planar array 2 , and the aviation connector 4 is connected to the image data sampling circuit 3 through a cable 5 .

The near-focus and far-infrared lens 1 is a fixed-focus wide-angle lens with an F1 aperture and a focal length of 3.6mm. The field of view range is greater than 90 degrees. It is made of germanium glass technology, with anti-reflection coating and distortion correction, and the distortion rate is less than 30%. The depth of field is 100-500mm, the aluminum lens barrel is used, the inner wall is blackened, and the emissivity is greater than 95%.

The far-infrared band focal plane array 2 is an uncooled infrared focal plane array working in the long infrared band, with a resolution above 320×240, a NETD value better than 0.2K, a nominal operating temperature of 300K, and an operating temperature range of - 50~800C.

The surroundings of the aviation joint 4 are sealed with silica gel, and the depth L of the silica gel is greater than 3 times the opening size D, which can prevent electromagnetic leakage.

The connecting cable 5 is a shielded wire with no less than 19 cores, which distinguishes digital signals such as timing and analog signals such as focal plane reference voltage and video output, and sets two shielded wires respectively.

Referring to accompanying drawing 2, the timing generation CPLD in the described image data sampling circuit 3 is realized by the CPLD of the following 300,000 gates and space-grade compatible model; the reference voltage array is matched with 1% accuracy by a power supply reference chip with a temperature drift not greater than 100ppm/°C The resistor generates the reference voltage required by the focal plane array and the common-mode voltage and reference voltage required for differential input AD sampling. All reference voltages form a stable voltage reference through the power filter circuit; the sampling resolution of the AD sampling unit is selected to be more than 12 bits; The front end of the AD sampling unit is provided with a signal conditioning unit, which adopts a fixed voltage bias and a fixed gain, wherein the voltage gain is equal to the common-mode voltage of the AD sampling.

The common-mode voltage and the gain of the signal conditioning circuit are selected according to the following rules: Make the amplitude range of the effective output signal of the detector match the input range of AD sampling to achieve the best sampling resolution.

The invention is applicable to the detection of moving objects in a small size (less than 1m) closed constant temperature environment at normal temperature.

Claims (10)

1. normal-temperature infrared inner satellite imaging detector, it is characterized in that: comprise nearly burnt far infrared camera lens, far infrared band focal plane arrays (FPA) and image data samples circuit, described nearly burnt far infrared camera lens and the far infrared band focal plane arrays (FPA) formation camera lens-focal plane array column unit that is connected, described image data samples circuit is connected with image data processing unit and constitutes circuit unit, and the image data samples circuit in the described circuit unit is connected by cable with far infrared band focal plane arrays (FPA) in camera lens-focal plane array column unit.

2. normal-temperature infrared inner satellite imaging detector according to claim 1, it is characterized in that: described camera lens and focal plane array column unit are installed in the shell, the aluminum metal sealing that described shell is all handled through blackout with inside surface except that the cable interface of rear end.

3. normal-temperature infrared inner satellite imaging detector according to claim 1, it is characterized in that: be connected with Aviation Connector between described far infrared band focal plane arrays (FPA) and the cable, adopt the silica gel sealing around the described Aviation Connector 4, silica gel degree of depth L is greater than 3 times of opening size D.

4. normal-temperature infrared inner satellite imaging detector according to claim 1, it is characterized in that: described nearly burnt far infrared camera lens adopts more than field angle 90 degree, the depth of field is the tight shot of 100～500mm, and fixes with described far infrared band focal plane arrays (FPA) relative distance.

5. normal-temperature infrared inner satellite imaging detector according to claim 1 is characterized in that: described far infrared band focal plane array is classified the non-refrigeration type infrared focal plane array that is operated in far infrared band as.

6. normal-temperature infrared inner satellite imaging detector according to claim 1, it is characterized in that: described image data samples circuit is by the sequential generating unit, the AD sampling unit, the reference voltage array is formed, described CPLD produces described far infrared band focal plane array image-forming and the required sequential of difference input AD sampling unit, described reference voltage array produces required reference voltage of described far infrared band focal plane arrays (FPA) and required common mode voltage and the reference voltage of described difference input AD sampling unit, and described AD sampling unit is connected to described far infrared band focal plane arrays (FPA).

7. normal-temperature infrared inner satellite imaging detector according to claim 6 is characterized in that: described sequential generating unit adopts the CPLD below 300,000, and described reference voltage array floats linear power supply chip connection precision resister by low temperature and forms.

8. normal-temperature infrared inner satellite imaging detector according to claim 7 is characterized in that: described low temperature floats the linear power supply chip and floats the regulated power supply chip that is not more than 100ppm/ ℃ for temperature, and described precision resister is the resistance of 1% precision.

9. normal-temperature infrared inner satellite imaging detector according to claim 6, it is characterized in that: be connected with signal conditioning circuit between the analog signal output of described infrared focal plane array and AD sampling unit, described signal conditioning circuit has fixed gain and fixed voltage biasing.

10. normal-temperature infrared inner satellite imaging detector according to claim 9 is characterized in that: the gain of described common mode voltage and signal conditioning circuit is selected as follows: the amplitude range of effective output signal of described normal-temperature infrared inner satellite imaging detector and the input range of AD sampling unit are complementary.

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