CN2849660Y - High-precision polarized light navigator - Google Patents

Abstract

The utility model relates to a high-precision polarized light navigator which realizes navigation by measuring the distribution of sky polarized light, which comprises a polarized light receiving system composed of a first polarized light lens barrel, a second polarized light lens barrel, a third polarized light lens barrel and a fourth polarized light lens barrel which have the same structure, wherein a light beam break over device, a polarization modulation system and a photodetector array are orderly arranged in the output direction of the polarized light receiving system; a locking phase amplification circuit, a logarithmic amplification circuit, a data acquisition card and a computer are connected behind the photodetector array in sequence. Two paths of polarized light signals received by the photodetector array are converted into electrical signals which are delivered to the computer to do signal processing by the logarithmic amplification circuit and the locking phase amplification circuit. Thus, the navigation of moving objects is realized. The utility model has the characteristics of simple structure, good reliability, high navigation accuracy, etc. The utility model is suitable for the real-time navigation of vehicles and moving objects, such as ships, airplanes, automobiles, robots, etc.

Description

High precision polarized light navigating instrument

Technical field

The utility model relates to the navigation of the vehicles such as steamer, aircraft, vehicle and robot and moving object, particularly a kind of direct high precision polarized light navigating instrument that day aerial polarized light navigates that utilizes.

Background technology

Though sunshine itself is not a polarized light, when it penetrates atmospheric envelope, be subjected to the scattering of atmospheric molecule or other particle, become the only dominant polarized light of vibration on vibration or a certain direction on a certain direction.Because the plane that the polarization direction of the scattered light of day aerial any point is all formed perpendicular to the sun, observer and this point, thus according to any one position of sun, people can determine the polarized light view of whole sky.Otherwise, even at cloudy day or the sun below the local horizon, by the sky polarized light view also position of the deducibility sun.Cooperate time reference and astronomical ephemeris just to know the position at observer place, reach navigation purpose.

Calendar year 2001, Australian Kane Usher, Peter Ridley and Peter Corke have proposed with the technology of camera as the polarized light compass, see technology (Kane Usher formerly, PeterRidley and Peter Corke, " A Camera as a Polarized light Compass:Preliminary Experiments ", Proc.2001 Australian Conference onRobotics and Automation Sydney, 14-15 November 2001,116-120).

Formerly in the technology, the azimuthal relation of the relative sun meridian with the observer of the light intensity of the sky polarized light that detector records can be expressed as for this:

f(φ)＝K(1+dcos(2φ)) (1)

In the formula: k is the engineering factor, and d is a degree of polarization, and φ is with respect to the meridianal orientation of the sun, and f (φ) is an average luminous intensity.Relation by formula (1) provides just can solve position angle φ.

This is the shortcoming of technology formerly:

(1), need record the light intensity value of several particular orientation (0 °, 45 °, 90 °) in advance, introduced the orientation angle error, directly have influence on azimuthal measuring accuracy;

(2), system is owing to adopt the sky scan mode, increased scanning device, measuring speed is slow, has increased system cost and volume, has reduced the reliability of system.

Summary of the invention

The purpose of this utility model is in order to overcome the deficiency of above-mentioned technology formerly, a kind of high precision polarized light navigating instrument to be provided.This navigating instrument should have simple in structure, does not have mechanical scanning device, characteristics such as precision height.

Technical solution of the present utility model is as follows:

A kind of high precision polarized light navigating instrument comprises: the polarized light receiving system that the first polarized light lens barrel that structure is identical, the second polarized light lens barrel, the 3rd polarized light lens barrel and the 4th polarized light lens barrel constitute; Outbound course in this polarized light receiving system is light beam steering device, Polarization Modulation system and photodetector array in turn, connects phase-locked amplifying circuit, logarithm amplifying circuit, data collecting card and computing machine after this photodetector array more successively.

The first polarized light lens barrel of described polarized light receiving system is made of first broad band pass filter, first analyzer and first convergent lens placed successively with optical axis ground in the working direction of light; The described second polarized light lens barrel is made of second broad band pass filter, second analyzer, second convergent lens, described the 3rd polarized light lens barrel is made of the 3rd broad band pass filter, the 3rd analyzer, the 3rd convergent lens, described the 4th polarized light lens barrel is made up of the 4th broad band pass filter, the 4th analyzer, the 4th convergent lens, and wherein the polarization direction of first analyzer and second analyzer is mutually orthogonal; The polarization direction of the 3rd analyzer and the 4th analyzer is mutually orthogonal, and first analyzer becomes 60 ° of angles with the 3rd analyzer optical axis.

Described broad band pass filter is an interference filter.

Described Polarization Modulation system is made of the first achromatism quarter wave plate of placing successively with optical axis ground on the light beam working direction, light ball modulator, the second achromatism quarter wave plate and analyzer, and wherein the quick shaft direction of the first achromatism quarter wave plate and the second achromatism quarter wave plate is mutually orthogonal.

Described photodetector array is made of photoelectric diode, photomultiplier, photoelectric cell or CCD array.

Described analyzer is polarization splitting prism or polaroid or the parallel flat that is coated with rete.

Described Polarization Modulation system is photoelastic modulating system, magneto-optic modulating system or electro-optic modulation system.

Working condition of the present utility model is as follows:

It aerial scattered light incides the first polarized light lens barrel, and the second polarized light lens barrel is in the 3rd polarized light lens barrel and the 4th polarized light lens barrel.Incide polarized light in the first polarized light lens barrel at first through becoming light beam behind first bandpass filter with certain bandwidth, this light beam becomes linearly polarized light after through first analyzer, the polarization direction is identical with the optical axis direction of first analyzer, and this polarized light becomes parallel light emergence behind first convergent lens.Scattered light propagation condition in the second polarized light lens barrel, the 3rd polarized light lens barrel and the 4th polarized light lens barrel is identical with scattered light situation in the first polarized light lens barrel.After the outgoing 4 bundle parallel beam is injected in the described light path turnover device, and this light path turnover device further narrows down to the lateral separation of 4 light beams in the incident bore scope of Polarization Modulation system.4 bundle directional lights after turnover impinge perpendicularly on first achromatic waveplate of Polarization Modulation system, incide light ball modulator, second achromatism quarter wave plate and the analyzer then successively.Wherein the one the second three four-tape pass filters are identical with the spectral range of the first achromatism quarter wave plate, the second achromatism quarter wave plate.One of them 50KHz ac modulation signal is added on the described light ball modulator, variation along with AC signal, incide on the analyzer after inciding the change of polarized direction of the polarized light on this light ball modulator, and this analyzer changes with the incident polarization direction the transmitance that is radiated at the polarized light above it.When the angle between polarization of incident light direction and the analyzer polarization direction is 0 or during π, its transmitance maximum, and angle is when being pi/2, its transmitance minimum.The magnitude of voltage that is added on the light ball modulator by change can change the polarization direction of light ball modulator emergent light like this, and then changes the light intensity that sees through at the analyzer place.Like this direct current signal that detects is transformed into the 50KHz AC signal, thereby has improved the signal to noise ratio (S/N ratio) and the sensitivity of system significantly.Polarized light after the modulation is received by photodetector array.The electric signal that receives is imported in the phase-locked amplifying circuit, and the direct current signal that obtains is sent into computing machine by data collecting card and carried out data processing and demonstration after the logarithm amplifying circuit amplifies.

The light intensity that the described first polarized light lens barrel, the second polarized light lens barrel, the 3rd polarized light lens barrel and the 4th polarized light lens barrel detect is respectively:

Si(φ)＝KI[1+dcos(2φ _i-2φ _max)(1+sinσ)] (2)

Wherein $\mathrm{\σ}=\frac{\mathrm{\π}}{2}\sin \left(2\mathrm{\πft}\right),i=\mathrm{1,2,3,4}---\left(3\right)$

In the following formula: I is the total light intensity that detects, I=I _Max+ I _Min, I _MaxAnd I _MinBe respectively the minimum and maximum value of light intensity, d degree of polarization, φ are that current location is with respect to the meridianal position angle of the sun, φ _MaxBe the value of s φ when getting maximal value, K constant, f are the modulating frequencies of modulator.

Wherein the optical axis direction of first analyzer and second analyzer is vertical mutually, and the optical axis direction of the 3rd analyzer and the 4th analyzer is vertical mutually.The optical axis direction of first analyzer and the 3rd analyzer, the optical axis direction of second analyzer and the 4th analyzer becomes 60 ° respectively.(2) formula can be rewritten as after ignoring the DC component constant amplitude:

S _{1，2，3，4}(φ)＝KI[1+dcos(2φ _{1，2，3，4}-2φ _max)sinσ] (4)

Signal shown in the formula (4) and modulation signal are input in the described phase-locked amplifying circuit jointly, obtain the amplitude of polarized light lens barrel four road signals.The logarithm difference that obtains two paths of signals behind the electric signal process logarithm amplification of the first polarized light lens barrel and the output of the second polarized light lens barrel and the treatment circuit is:

$p_{\mathrm{1,2}}\left(\mathrm{\φ}\right)=\log \left(\frac{1+d\cos \left(2\mathrm{\φ}\right)}{1-d\cos \left(2\mathrm{\φ}\right)}\right)---\left(5\right)$

The logarithm difference that obtains two paths of signals behind the electric signal process logarithm amplification of the 3rd polarized light lens barrel and the output of the 4th polarized light lens barrel and the treatment circuit is:

$p_{\mathrm{3,4}}\left(\mathrm{\φ}\right)=\log \left(\frac{1+d\cos (2\mathrm{\φ}-\frac{2\mathrm{\π}}{3})}{1-d\cos (2\mathrm{\φ}-\frac{2\mathrm{\π}}{3})}\right)---\left(6\right)$

Introduce intermediate variable p (φ):

$\frac{1}{10p\left(\mathrm{\φ}\right)+1}=\stackrel{\‾}{p}\left(\mathrm{\φ}\right)---\left(7\right)$

Then the value of φ can be written as:

$\mathrm{\φ}=\frac{1}{2}d\tan \left(\frac{{\stackrel{\‾}{p}}_1\left(\mathrm{\φ}\right)+2{\stackrel{\‾}{p}}_2\left(\mathrm{\φ}\right)-\frac{3}{2}}{\sqrt{3}({\stackrel{\‾}{p}}_1\left(\mathrm{\φ}\right)-\frac{1}{2})}\right)---\left(8\right)$

By can realize the precision navigation of moving objects such as steamer, aircraft, vehicle and robot to the high-acruracy survey of φ value.

The utility model has the advantages that:

Compare with technology formerly, the utility model does not have mechanical component, has simplified system architecture, has improved the stability and the reliability of system;

By adopting polarization Modulation, the direct current signal that detects is transformed into the 50KHz AC signal, reduce 1/f noise, thereby improved the signal to noise ratio (S/N ratio) and the sensitivity of system significantly, improved navigation accuracy.

Description of drawings

Fig. 1 is a high precision polarized light navigating instrument structural representation of the present utility model.

Embodiment

See also Fig. 1 earlier, Fig. 1 is the structural representation of high precision polarized light navigating instrument embodiment of the present utility model.As seen from the figure, the formation of the utility model high precision polarized light navigating instrument comprises: the polarized light receiving system that the first polarized light lens barrel 1 that structure is identical, the second polarized light lens barrel 2, the 3rd polarized light lens barrel 3 and the 4th polarized light lens barrel 4 constitute; Outbound course in this polarized light receiving system is light beam steering device 5, Polarization Modulation system 6, photodetector array 7 in turn, connects phase-locked amplifying circuit 8, logarithm amplifying circuit 9, data collecting card 10 and computing machine 11 more successively after this photodetector array 7.

The first polarized light lens barrel 1 of described polarized light receiving system is made of first broad band pass filter 101, first analyzer 102 and first plus lens 103 placed successively with optical axis ground in the working direction of light; The described second polarized light lens barrel 2 is made of second broad band pass filter 201, second analyzer 202, second plus lens 203, described the 3rd polarized light lens barrel 3 is made of the 3rd broad band pass filter 301, the 3rd analyzer 302, the 3rd plus lens 303, described the 4th polarized light lens barrel 4 is made up of the 4th broad band pass filter 401, the 4th analyzer 402, the 4th plus lens 403, and wherein the polarization direction of first analyzer 102 and second analyzer 202 is mutually orthogonal; The polarization direction of the 3rd analyzer 302 and the 4th analyzer 402 is mutually orthogonal, and first analyzer 102 becomes 60 ° with the 3rd analyzer 302 optical axises.

Described broad band pass filter is an interference filter.

Described Polarization Modulation system 6 is made of with analyzer 604 the first achromatism quarter wave plate of placing successively with optical axis ground on the light beam working direction 601, light ball modulator 602, the second achromatism quarter wave plate 603, and wherein the quick shaft direction of the first achromatism quarter wave plate 601 and the second achromatism quarter wave plate 603 is mutually orthogonal.

Described photodetector array 7 is made of photoelectric diode, photomultiplier, photoelectric cell or CCD array.

Described analyzer is polarization splitting prism or polaroid or the parallel flat that is coated with rete.

Described Polarization Modulation system is photoelastic modulating system, magneto-optic modulating system or electro-optic modulation system.

The same day, aerial scattered light incided in first polarized light lens barrel 1, the second polarized light lens barrel, 2, the three polarized light lens barrels 3 and the 4th polarized light lens barrel 4.The polarized light that incides in the first polarized light lens barrel 1 at first becomes the light beam with certain bandwidth through behind the bandpass filter 101, this light beam becomes linearly polarized light after through first analyzer 102, the polarization direction is identical with first analyzer, 102 optical axis directions, and this polarized light becomes parallel light emergence behind plus lens 103.Scattered light propagation condition in the second polarized light lens barrel 2, the 3rd polarized light lens barrel 3, the 4th polarized light lens barrel 4 is identical with scattered light situation in the first polarized light lens barrel 1.After the outgoing 4 bundle parallel beam is irradiated in the light path turnover device 5, and this light path turnover device 5 further narrows down to the lateral separation of 4 light beams in the incident bore scope of Polarization Modulation system 6.4 bundle directional lights after turnover impinge perpendicularly on first achromatic waveplate 601 of Polarization Modulation system 6, then successively through light ball modulator 602, the second achromatism quarter wave plate 603 and analyzer 604.Wherein first to fourth bandpass filter 101,201,301,401 and first achromatic waveplate 601, second achromatic waveplate, 603 spectral ranges are identical.One of them 50KHz ac modulation signal is added on the light ball modulator 602, variation along with AC signal, incide on the analyzer 604 after inciding the change of polarized direction of polarized light on the light ball modulator 602, change with the incident polarization direction and 604 pairs of analyzers are radiated at the transmitance of the polarized light above it.When the angle between the polarization direction of polarization of incident light direction and analyzer is 0 or during π, its transmitance maximum, when angle is pi/2, its transmitance minimum.The magnitude of voltage that is added on the light ball modulator 602 by change can change the polarization direction of light ball modulator 602 emergent lights like this, and then changes the light intensity that sees through at analyzer place 604.Like this direct current signal that detects is transformed into the 50KHz AC signal, thereby has improved the signal to noise ratio (S/N ratio) and the sensitivity of system significantly.Polarized light after the modulation is received by photodetector array 7.The electric signal that receives is imported in the phase-locked amplifying circuit 8, and the direct current signal that obtains is sent into computing machine 11 by data collecting card 10 and carried out data processing and demonstration after logarithm amplifying circuit 9 logarithms amplify.

Wherein light beam steering device 5, Polarization Modulation system 6, detector array 7, phase-locked amplifying circuit 8, logarithm amplifying circuit 9, data collecting card 10 are placed in the casing 12.

Said phase-locked amplifying circuit 8 is meant the circuit that utilizes principle of phase lock loop to realize signal extraction and amplification, as lock-in amplifier etc.

Said logarithm amplifying circuit 9 is meant the circuit that the direct current or the AC signal of input can be amplified by the logarithmic function rule.

Said achromatism quarter wave plate is meant can be with the wave plate of broadband incident light phase change pi/2.Said light ball modulator is meant the Polarization Modulation system that the elasto-optical effect of utilizing crystal is made, as HINDS modulator etc.

More particularly, the spectral range of the broad band pass filter of present embodiment is the 350-450 nanometer, described analyzer 102,202,302,402 and 604 is Glan-Taylor prism, achromatic waveplate is the quarter wave plate of bandwidth 350-450 nanometer, light ball modulator 602 is the HINDS modulator, and detector array 7 is 4 quadrant detectors.

Photodetector array converts the two-way polarized light signal that receives to electric signal, through phase-locked amplifying circuit and logarithm amplifying circuit, delivers to and carries out signal Processing in the computing machine, realizes the navigation of moving object.The utlity model has characteristics such as system architecture is simple, good reliability, navigation accuracy height.Be applicable to the real-time navigation of the vehicles such as boats and ships, aircraft, vehicle and robot and moving object.Our experiments show that the navigation accuracy of the utility model device is ± 2 ° when the sun is near middle day.

Claims (7)

1, a kind of high precision polarized light navigating instrument is characterized in that it comprises: the polarized light receiving system that the first polarized light lens barrel (1) that structure is identical, the second polarized light lens barrel (2), the 3rd polarized light lens barrel (3) and the 4th polarized light lens barrel (4) constitute; Outbound course in this polarized light receiving system is light beam steering device (5), Polarization Modulation system (6), photodetector array (7) in turn, and this photodetector array (7) connects phase-locked amplifying circuit (8), logarithm amplifying circuit (9), data collecting card (10) and computing machine (11) afterwards more successively.

2, high precision polarized light navigating instrument according to claim 1 is characterized in that the first polarized light lens barrel (1) of described polarized light receiving system is made of first broad band pass filter of placing successively with optical axis ground in the working direction of light (101), first analyzer (102) and first convergent lens (103); The described second polarized light lens barrel (2) is made of second broad band pass filter (201), second analyzer (202), second convergent lens (203), described the 3rd polarized light lens barrel (3) is made of the 3rd broad band pass filter (301), the 3rd analyzer (302), the 3rd convergent lens (303), described the 4th polarized light lens barrel (4) is made up of the 4th broad band pass filter (401), the 4th analyzer (402), the 4th convergent lens (403), and wherein first analyzer (102) is mutually orthogonal with the polarization direction of second analyzer (202); The 3rd analyzer (302) is mutually orthogonal with the polarization direction of the 4th analyzer (402), and first analyzer (102) becomes 60 ° of angles with the 3rd analyzer (302) optical axis.

3, high precision polarized light navigating instrument according to claim 1 is characterized in that described broad band pass filter is an interference filter.

4, high precision polarized light navigating instrument according to claim 1, it is characterized in that described Polarization Modulation system (6) is made of with analyzer (604) the first achromatism quarter wave plate of placing successively with optical axis ground on the light beam working direction (601), light ball modulator (602), the second achromatism quarter wave plate (603), wherein the first achromatism quarter wave plate (601) is mutually orthogonal with the quick shaft direction of the second achromatism quarter wave plate 603.

5, high precision polarized light navigating instrument according to claim 1 is characterized in that described photodetector array (7) is made of photoelectric diode, photomultiplier, photoelectric cell or CCD array.

6, high precision polarized light navigating instrument according to claim 1 is characterized in that described analyzer is polarization splitting prism or polaroid or the parallel flat that is coated with rete.

7, high precision polarized light navigating instrument according to claim 1 is characterized in that described Polarization Modulation system (6) is photoelastic modulating system, magneto-optic modulating system or electro-optic modulation system.