CN103398711B - The earth sensor that many visual fields are separated - Google Patents

Abstract

The present invention proposes the earth sensor that a kind of many visual fields are separated, and comprising: linear array infrared eye, for responsive earth CO ₂the thickness of infrared absorption band; Many visual fields system, for detecting the edge of earth infrared radiation and vacuum, measuring the Horizon circle that earth atmosphere radiative forcing is formed, and then obtaining the earth's core vector; Measuring unit, for according to the radius of the known earth and CO ₂the thickness of infrared absorption band calculates attitude of flight vehicle and height.The earth sensor that many visual fields of the present invention are separated not only can be applied on board the aircraft, not by the impact of the factors such as seasonal variations, earth surface and surface radiation difference on Horizon circle, height and the attitude information of accurate aircraft are provided, and data fusion can be carried out with other sensors, realize the independent navigation of aircraft.

Description

The earth sensor that many visual fields are separated

Technical field

The present invention relates to celestial navigation technical field, particularly relate to the earth sensor that a kind of many visual fields are separated.

Background technology

Infrared earth sensor is as a kind of important celestial navigation sensor, and the attitude being widely used in satellite such as to determine at the aspect.Infrared earth sensor is a kind of heat-sensing device, by the CO of detection earth limit 14-16 mu m waveband ₂absorption band, measures the Horizon circle that earth atmosphere radiative forcing is formed, thus overcomes the impact on Horizon circle of seasonal variations, earth surface and surface radiation difference.At present, although the shortcoming that infrared earth sensor has precision lower, because it has stronger tolerance to space ray, become a kind of major way that earth-orbiting satellite determines appearance.

Infrared earth sensor can be divided into static state infrared horizon and dynamic scanning type infrared horizon two kinds according to principle of work.Dynamic earth sensor technology is relatively ripe, but owing to there is mechanical moving element, weight and energy consumption are all larger, and the life-span is also limited, and development is subject to the restriction of each side; And static earth sensor moves due to its non-scan, in quality, power consumption, precision and serviceable life etc., all there is advantage than dynamic earth sensor, therefore static infrared senstive device has become the emphasis of various countries' research gradually.At present, earth sensor mainly applies to the attitude measurement of satellite, orbit altitude be 500km and more than, and most of earth sensor is monoscopic, is not suitable for the aircraft of low orbit especially 70km ~ 100km.

Therefore, design a kind of can be applicable to aircraft, high precision earth sensory system is necessary.It can not only provide high-precision attitude and elevation information for aircraft, and other sensors can also be coordinated to realize the autonomous astronomical navigation of aircraft.

Summary of the invention

The present invention is intended at least one of solve the problems of the technologies described above.

For this reason, first object of the present invention is to propose a kind of height and attitude information that can provide accurate aircraft, can carry out data fusion again with other sensors, the earth sensor that the many visual fields realizing the independent navigation of aircraft are separated.

The earth sensor that many visual fields of the present invention are separated, comprising: linear array infrared eye, described linear array infrared eye is used for responsive earth CO ₂the thickness of infrared absorption band; Many visual fields system, described many visual fields system, for detecting the edge of earth infrared radiation and vacuum, is measured the Horizon circle that earth atmosphere radiative forcing is formed, and then is obtained the earth's core vector; And measuring unit, described measuring unit is used for according to the radius of the known earth and CO ₂the thickness of infrared absorption band calculates attitude of flight vehicle and height.

In an example of the present invention, described many visual fields system comprises and being mutually in the horizontal plane by n projection visual field composition.

In an example of the present invention, to be wavelength the be CO of 14 ~ 16 μm of described linear array infrared eye sensitivity ₂infrared absorption band.

In an example of the present invention, described measuring unit is by described linear array infrared eye, and namely linear array infrared CCD, is directly converted to analog current signal by optical signalling, current signal, through amplifying and analog to digital conversion, realizes the acquisition of image, storage, transmission, process and reproduction.

In an example of the present invention, described measuring unit is for the aircraft of flying height at 70km ~ 100km.

In an example of the present invention, in described measuring unit, set up earth sensor observation earth model, obtain direction, the earth's core by responsive Horizon circle, calculate attitude and the elevation information of described aircraft according to following algorithm:

(1) according to described observation earth model, geometric relationship is had wherein, θ represents the acute angle folded by the earth's core vector and incident ray, and be the established angle of the earth sensor that described many visual fields are separated, R is earth radius, and r is CO ₂infrared absorption tape thickness;

(2) suppose that aircraft initial coordinate is X ₁y ₁z ₁, aircraft is successively around the angle of Z axis, X-axis, Y-axis rotation α, β, γ, and the body coordinate system after rotation is X ₂y ₂z ₂because described many visual fields earth sensor is about Z axis Rotational Symmetry, and described observation earth model is also about Z week Rotational Symmetry, therefore the rotation around Z axis does not affect for observed result, therefore get α=0, obtain according to Eulerian angle rotation matrix the attitude rotation matrix that aircraft initial coordinate is tied to new coordinate system:

$C_{21}=\left[\begin{array}{ccc}\cos \mathrm{\γ}& \sin \mathrm{\β}\sin \mathrm{\γ}& -\cos \mathrm{\β}\sin \mathrm{\γ}\\ 0& \cos \mathrm{\β}& \sin \mathrm{\β}\\ \sin \mathrm{\γ}& -\sin \mathrm{\β}\cos \mathrm{\γ}& \cos \mathrm{\β}\cos \mathrm{\γ}\end{array}\right]$

Thus the earth's core vector obtained under new coordinate system:

${\stackrel{\→}{E}}_{21}=C_{21}{\stackrel{\→}{E}}_{11}=\left[\begin{array}{ccc}\cos \mathrm{\γ}& \sin \mathrm{\β}\sin \mathrm{\γ}& -\cos \mathrm{\β}\sin \mathrm{\γ}\\ 0& \cos \mathrm{\β}& \sin \mathrm{\β}\\ \sin \mathrm{\γ}& -\sin \mathrm{\β}\cos \mathrm{\γ}& \cos \mathrm{\β}\cos \mathrm{\γ}\end{array}\right]\left[\begin{array}{c}0\\ 0\\ -1\end{array}\right]$

$={\left[\begin{array}{ccc}\cos \mathrm{\β}\sin \mathrm{\γ}& -\sin \mathrm{\β}& -\cos \mathrm{\β}\cos \mathrm{\γ}\end{array}\right]}^T$

(3) the earth's core direction vector after rotating is calculated by linear array infrared CCD measurement result:

${\stackrel{\→}{E}}_{22}=\frac{({\stackrel{\→}{X}}_{23}-{\stackrel{\→}{X}}_{21})\×({\stackrel{\→}{X}}_{22}-{\stackrel{\→}{X}}_{21})}{\left|\right|({\stackrel{\→}{X}}_{23}-{\stackrel{\→}{X}}_{21})\×({\stackrel{\→}{X}}_{22}-{\stackrel{\→}{X}}_{21})\left|\right|}$

Wherein:

U ₁, u ₂, u ₃be respectively the coordinate points on 3 described linear array infrared CCDs, f is the focal length of camera lens in visual field, the angle of original light and Z axis, it is three incident raies and the angle of described corresponding linear array infrared CCD optical axis.

(4) attitude angle beta of described aircraft can be calculated by above-mentioned formula, γ is:

$\mathrm{\β}=-\arcsin {\stackrel{\→}{E}}_{22}\left(2\right)$

$\mathrm{\γ}=-\arctan \frac{{\stackrel{\→}{E}}_{22}\left(1\right)}{{\stackrel{\→}{E}}_{22}\left(3\right)}$

Wherein, the earth's core direction vector after described rotation respectively three elements;

The flying height of aircraft is:

The earth sensor that many visual fields of the present invention are separated not only can be applied on board the aircraft, not by the impact of the factors such as seasonal variations, earth surface and surface radiation difference on Horizon circle, height and the attitude information of accurate aircraft are provided, and data fusion can be carried out with other sensors, realize the independent navigation of aircraft.

The aspect that the present invention adds and advantage will part provide in the following description, and part will become obvious from the following description, or be recognized by practice of the present invention.

Accompanying drawing explanation

The present invention above-mentioned and/or additional aspect and advantage will become obvious and easy understand from the following description of the accompanying drawings of embodiments, wherein,

Fig. 1 is the structural representation of the earth sensor observation earth that three visual fields of the present invention's example are separated;

Fig. 2 (a) is three visual field schematic diagram of the earth sensor that three visual fields of the present invention's example are separated, and Fig. 2 (b) is the projective distribution schematic diagram of three visual fields in XOY plane of Fig. 2 (a);

Fig. 3 is the earth sensor coordinate system definition schematic diagram that three visual fields of the present invention's example are separated;

Fig. 4 is the ordinate transform schematic diagram of the earth sensor that three visual fields of the present invention's example are separated;

Fig. 5 is the simplified diagram of the incident ray of a visual field of the earth sensor that three visual fields of the present invention's example are separated; With

Fig. 6 is the overall schematic of three visual fields of the earth sensor that three visual fields of the present invention's example are separated.

Embodiment

Be described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Being exemplary below by the embodiment be described with reference to the drawings, only for explaining the present invention, and can not limitation of the present invention being interpreted as.On the contrary, embodiments of the invention comprise fall into attached claims spirit and intension within the scope of all changes, amendment and equivalent.

In describing the invention, it is to be appreciated that term " first ", " second " etc. are only for describing object, and instruction or hint relative importance can not be interpreted as.In describing the invention, it should be noted that, unless otherwise clearly defined and limited, term " is connected ", " connection " should be interpreted broadly, such as, can be fixedly connected with, also can be removably connect, or connect integratedly; Can be mechanical connection, also can be electrical connection; Can be directly be connected, also indirectly can be connected by intermediary.For the ordinary skill in the art, concrete condition above-mentioned term concrete meaning in the present invention can be understood.In addition, in describing the invention, except as otherwise noted, the implication of " multiple " is two or more.

Describe and can be understood in process flow diagram or in this any process otherwise described or method, represent and comprise one or more for realizing the module of the code of the executable instruction of the step of specific logical function or process, fragment or part, and the scope of the preferred embodiment of the present invention comprises other realization, wherein can not according to order that is shown or that discuss, comprise according to involved function by the mode while of basic or by contrary order, carry out n-back test, this should understand by embodiments of the invention person of ordinary skill in the field.

Below with reference to the accompanying drawings describe the earth sensor be separated according to many visual fields of the embodiment of the present invention, and describe in detail for the earth sensor that three visual fields are separated.

The earth sensor of the three visual fields separation of one embodiment of the present of invention, comprising: linear array infrared eye, for responsive earth CO ₂the thickness of infrared absorption band; Many visual fields system, for detecting the edge of earth infrared radiation and vacuum, measuring the Horizon circle that earth atmosphere radiative forcing is formed, and then obtaining the earth's core vector; Measuring unit is used for according to the radius of the known earth and CO ₂the parameters such as the thickness of infrared absorption band calculate attitude of flight vehicle and height.

Particularly, many visual fields system of earth sensor that three visual fields of one embodiment of the present of invention are separated comprises and being mutually in the horizontal plane by 3 projections visual field composition.

To be wavelength the be CO of 14 ~ 16 μm of the linear array infrared eye sensitivity of the earth sensor that three visual fields of one embodiment of the present of invention are separated ₂infrared absorption band.

The measuring unit of the earth sensor of the three visual fields separation of one embodiment of the present of invention is by linear array infrared eye, i.e. linear array infrared CCD, directly optical signalling is converted to analog current signal, current signal, through amplifying and analog to digital conversion, realizes the acquisition of image, storage, transmission, process and reproduction.

The measuring unit of the earth sensor of the three visual fields separation of one embodiment of the present of invention is for the aircraft of flying height at 70km ~ 100km.

Further, by measuring unit according to the radius of the known earth and CO ₂the parameters such as the thickness of infrared absorption band are carried out the attitude of aircraft and are highly resolved.Concrete steps are as follows:

(1) earth surface CO as shown in Figure 1, is got ₂the atmospheric thickness r=20km of infrared absorption band, earth radius R=6370km, when aircraft altitude is h=70km, if light ray parallel optical axis vertical irradiation is on line array CCD photosensitive region, then have geometric relationship: wherein, θ is the angle of light and the earth's core vector.When aircraft is motionless, brings data into and can obtain optical-axis and the acute angle folded by Z axis (being initially the earth's core vector axle): θ=82.86 °;

(2) as shown in Figures 2 and 3, set up the coordinate system of three visual field earth sensors, wherein the optical axis of three visual fields is uniformly distributed in the projection of surface level XOY plane, is mutually 120 ° of angles, and optical axis 1 in XOZ plane, and is positioned at immediately below X-axis;

(3) as shown in Figure 4, suppose that aircraft initial coordinate is X ₁y ₁z ₁, aircraft is successively around the angle of Z axis, X-axis, Y-axis rotation α, β, γ, and the body coordinate system after rotation is X ₂y ₂z ₂because three visual field earth sensors are about Z axis Rotational Symmetry, and observation earth model is also about Z week Rotational Symmetry, and the rotation therefore around Z axis does not affect for observed result, therefore get α=0, obtain according to Eulerian angle rotation matrix the attitude rotation matrix that initial coordinate is tied to new coordinate system:

$C_{21}=\left[\begin{array}{ccc}\cos \mathrm{\γ}& \sin \mathrm{\β}\sin \mathrm{\γ}& -\cos \mathrm{\β}\sin \mathrm{\γ}\\ 0& \cos \mathrm{\β}& \sin \mathrm{\β}\\ \sin \mathrm{\γ}& -\sin \mathrm{\β}\cos \mathrm{\γ}& \cos \mathrm{\β}\cos \mathrm{\γ}\end{array}\right]$

Thus the earth's core vector that can obtain under new coordinate system

${\stackrel{\→}{E}}_{21}=C_{21}{\stackrel{\→}{E}}_{11}=\left[\begin{array}{ccc}\cos \mathrm{\γ}& \sin \mathrm{\β}\sin \mathrm{\γ}& -\cos \mathrm{\β}\sin \mathrm{\γ}\\ 0& \cos \mathrm{\β}& \sin \mathrm{\β}\\ \sin \mathrm{\γ}& -\sin \mathrm{\β}\cos \mathrm{\γ}& \cos \mathrm{\β}\cos \mathrm{\γ}\end{array}\right]\left[\begin{array}{c}0\\ 0\\ -1\end{array}\right]$

$={\left[\begin{array}{ccc}\cos \mathrm{\β}\sin \mathrm{\γ}& -\sin \mathrm{\β}& -\cos \mathrm{\β}\cos \mathrm{\γ}\end{array}\right]}^T$

Measure by linear array infrared CCD the signaling point obtained and calculate the earth's core unit vector after rotation namely

${\stackrel{\→}{E}}_{22}=\frac{({\stackrel{\→}{X}}_{23}-{\stackrel{\→}{X}}_{21})\×({\stackrel{\→}{X}}_{22}-{\stackrel{\→}{X}}_{21})}{\left|\right|({\stackrel{\→}{X}}_{23}-{\stackrel{\→}{X}}_{21})\×({\stackrel{\→}{X}}_{22}-{\stackrel{\→}{X}}_{21})\left|\right|}$

Wherein:

the angle of original light and Z axis, as shown in Figure 3 and Figure 5, original light is be injected in the true origin of infrared CCD along optical axis, with visual field established angle θ numerically equal.U ₁, u ₂, u ₃be respectively the coordinate points on 3 linear array infrared CCDs, f is the focal length of camera lens in visual field, be three incident raies and the angle of corresponding linear array infrared CCD optical axis, as shown in Figure 6.

Due to with identical, thus obtain attitude angle beta, the γ and flying height h of aircraft:

$\mathrm{\β}=-\arcsin {\stackrel{\→}{E}}_{22}\left(2\right)$

$\mathrm{\γ}=-\arctan \frac{{\stackrel{\→}{E}}_{22}\left(1\right)}{{\stackrel{\→}{E}}_{22}\left(3\right)}$

Wherein, the earth's core direction vector after described rotation respectively three elements.

Further, in an example of the present invention, by the emulation of the earth sensor to three visual fields separation, obtain when attitude angle beta, γ change respectively in the scope of ± 10 °, when the flying height h of aircraft changes 100m, on linear array infrared CCD, signaling point changes in coordinates amount is 0.68pixel, within the scope of CCD measuring accuracy 0.1pixel, so the measuring accuracy of flying height can reach 100m.

In addition, for CCD1, when aircraft altitude is 70km, attitude angle beta=0 °, the limited angle γ measuring error caused of measuring accuracy is about 3.3 "; For CCD2, when aircraft altitude is 70km, γ=0 °, the limited angle beta measuring error caused of measuring accuracy is about 3.8 ".Consider above-mentioned simulation analysis, the error that the earth sensor that three visual fields obtaining an example of the present invention are separated measures attitude angle is about 3.8 " (namely getting the greatest measure of its attitude error).Therefore, the earth sensor that many visual fields of the present invention are separated can obtain flying height h and attitude angle beta, the γ of high-precision aircraft.

The earth sensor that many visual fields of the present invention are separated not only can be applied on board the aircraft, not by the impact of the factors such as seasonal variations, earth surface and surface radiation difference on Horizon circle, height and the attitude information of accurate aircraft are provided, and data fusion can be carried out with other sensors, realize the independent navigation of aircraft.

In the description of this instructions, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present invention or example.In this manual, identical embodiment or example are not necessarily referred to the schematic representation of above-mentioned term.And the specific features of description, structure, material or feature can combine in an appropriate manner in any one or more embodiment or example.

Although illustrate and describe embodiments of the invention, those having ordinary skill in the art will appreciate that: can carry out multiple change, amendment, replacement and modification to these embodiments when not departing from principle of the present invention and aim, scope of the present invention is by claim and equivalents thereof.

Claims (6)

1. the earth sensor that visual field more than is separated, is characterized in that, comprising:

Linear array infrared eye, described linear array infrared eye is used for responsive earth CO ₂the thickness of infrared absorption band;

Many visual fields system, described many visual fields system, for detecting the edge of earth infrared radiation and vacuum, is measured the Horizon circle that earth atmosphere radiative forcing is formed, and then is obtained the earth's core vector; And

Measuring unit, described measuring unit is used for according to the radius of the known earth and CO ₂the thickness of infrared absorption band calculates attitude of flight vehicle and height.

2. the earth sensor that is separated of many visual fields as claimed in claim 1, is characterized in that, described many visual fields system comprises and being mutually in the horizontal plane by n projection visual field composition.

3. the earth sensor that is separated of many visual fields as claimed in claim 1, is characterized in that, to be wavelength the be CO of 14 ~ 16 μm of described linear array infrared eye sensitivity ₂infrared absorption band.

4. the earth sensor of many visual fields separation as claimed in claim 1, it is characterized in that, described measuring unit is by described linear array infrared eye, i.e. linear array infrared CCD, directly optical signalling is converted to analog current signal, current signal, through amplifying and analog to digital conversion, realizes the acquisition of image, storage, transmission, process and reproduction.

5. the earth sensor of many visual fields separation as claimed in claim 1, it is characterized in that, described measuring unit is for the aircraft of flying height at 70km ~ 100km.

6. the earth sensor of many visual fields separation as claimed in claim 1, it is characterized in that, in described measuring unit, set up earth sensor observation earth model, obtain direction, the earth's core by responsive Horizon circle, calculate attitude and the elevation information of described aircraft according to following algorithm:

(1) according to described observation earth model, geometric relationship is had wherein, θ represents the acute angle folded by the earth's core vector and incident ray, and be the established angle of the earth sensor that described many visual fields are separated, R is earth radius, and r is CO ₂infrared absorption tape thickness, h is aircraft altitude;

(2) suppose that aircraft initial coordinate is X ₁y ₁z ₁, aircraft is successively around the angle of Z axis, X-axis, Y-axis rotation α, β, γ, and the body coordinate system after rotation is X ₂y ₂z ₂because described many visual fields earth sensor is about Z axis Rotational Symmetry, and described observation earth model is also about Z week Rotational Symmetry, therefore the rotation around Z axis does not affect for observed result, therefore get α=0, obtain according to Eulerian angle rotation matrix the attitude rotation matrix that aircraft initial coordinate is tied to new coordinate system:

Thus the earth's core vector obtained under new coordinate system:

(3) measurement result obtained by described linear array infrared CCD calculates the earth's core direction vector after rotating:

Wherein:

U ₁, u ₂, u ₃be respectively the coordinate points on 3 described linear array infrared CCDs, f is the focal length of camera lens in described visual field, the angle of original light and Z axis, it is three incident raies and the angle of corresponding linear array infrared CCD optical axis;

(4) attitude angle beta of described aircraft can be calculated by above-mentioned formula, γ is:

Wherein, the earth's core direction vector after described rotation respectively three elements;

The flying height of aircraft is: