阅读说明：本技术 一种考虑暗电流的水下偏振传感器多参数优化标定方法 (Underwater polarization sensor multi-parameter optimization calibration method considering dark current ) 是由 杨健 游春春 胡鹏伟 刘鑫 郭雷 于 2021-11-25 设计创作，主要内容包括：本发明公开了一种考虑暗电流的水下偏振传感器多参数优化标定方法。首先,针对水下弱光环境下,感光芯片暗电流影响偏振传感器偏振信息准确度的问题,建立考虑暗电流的偏振传感器响应模型；其次,根据偏振传感器响应模型建立偏振信息与暗电流等参数的映射关系；然后,建立偏振信息的多参数优化函数,对偏振传感器暗电流等参数进行标定；最后,基于标定的暗电流等参数以及偏振传感器响应模型,实时解算偏振信息。本发明充分考虑水下弱光环境下,暗电流对偏振传感器偏振信息获取精度的影响,引入暗电流参数完善偏振传感器模型并通过多参数优化标定对偏振传感器进行优化标定,提高了偏振传感器在水下环境的偏振信息获取精度以及环境适应性。(The invention discloses a multi-parameter optimization calibration method of an underwater polarization sensor considering dark current. Firstly, aiming at the problem that dark current of a photosensitive chip influences the accuracy of polarization information of a polarization sensor in an underwater weak light environment, establishing a polarization sensor response model considering the dark current; secondly, establishing a mapping relation of parameters such as polarization information, dark current and the like according to a polarization sensor response model; then, establishing a multi-parameter optimization function of polarization information, and calibrating parameters such as dark current of the polarization sensor; and finally, calculating polarization information in real time based on the calibrated parameters such as the dark current and the response model of the polarization sensor. The method fully considers the influence of the dark current on the polarization information acquisition precision of the polarization sensor in the underwater weak light environment, introduces the dark current parameter perfection polarization sensor model and carries out optimized calibration on the polarization sensor through multi-parameter optimized calibration, and improves the polarization information acquisition precision and the environmental adaptability of the polarization sensor in the underwater environment.)

1. A multi-parameter optimization calibration method of an underwater polarization sensor considering dark current is characterized by comprising the following steps:

(1) dark current analysis for underwater low light environmentDConstructing channels for the influence mechanism and error transmission process of the polarization sensorkWherein, in the step (A),k=1、2…n，nnot less than 3, including dark currentDThe polarization sensor model multi-parameter vector gamma _k Establishing a channel with respect to a polarization sensorkOf (d) a multi-parameter vector Γ _k Polarization sensor response modelV _k (Γ _k )；

(2) The polarization sensor channel obtained according to the step (1)kResponse model ofV _k (Γ _k ) Are combined togethernResponse of each channel sensor, and obtaining polarization information by using least squares and a multi-parameter vector gamma of a polarization sensor model _k The mapping relationship of (1): intensity of polarized lightI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k )；

(3) Establishing a polarization-based light intensity in consideration of an underwater time-varying light intensity environmentI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Model parameter vector Γ of _k Multiple parameter optimization function off(Γ _k ) Obtained by a non-linear least squares method comprisingDark currentDThe polarization sensor model multi-parameter vector gamma _k Optimal estimation of (2);

(4) the multi-parameter vector gamma of the polarization sensor model estimated in the step (3) _k Substituting pending polarization sensor response modelV _k (gamma), simultaneous multi-channel sensor response resolving real-time polarized light intensityIAzimuth of polarizationAnd degree of polarizationd。

2. The underwater polarization sensor multi-parameter optimization calibration method considering the dark current as claimed in claim 1, wherein:

in the step (1), the method is based on the Malus lawiThe relationship between the current generated by each photosensitive chip and the incident polarized light is as follows:

wherein the content of the first and second substances,C _i is as followsiThe current is output by each light-sensing chip,K _Ii is as followsiThe light intensity response parameter of each light sensing chip,Iin order to input the light intensity,D _i is as followsiThe dark current of each light-sensitive chip is measured,dis the degree of polarization of the beam of light,in order to be the polarization azimuth angle,andis as followsiThe light intensity coefficient and the polarization degree coefficient caused by the extinction ratio error of the polaroid in the polarized light sensed by the photosensitive chip,forming an included angle between the installation position of the polaroid of the corresponding channel and the zero position of the sensor;

opposite polarization sensor pass through oppositei、jThe output currents of the two photosensitive chips are subjected to logarithmic amplification operation, and the dark current error transmission process is analyzed, so that the dark current parameters of the opposite photosensitive chip are consideredD _i 、D _j Polarization sensor channel ofkThe output of (c) is:

wherein the content of the first and second substances,Ka _k is a channelkThe amplification factor of the logarithmic amplifier is,V _OSOk is a channelkThe amplifier outputs a bias voltage value;

building a channelkMulti-parameter vector gamma of polarization sensor model to be estimated _k Expressed as:

polarization sensor response modelV(Γ) is expressed as:

Γ _k is a vector and 1-8 are the numbers of the elements in the vector.

3. The underwater polarization sensor multi-parameter optimization calibration method considering the dark current as claimed in claim 1, wherein:

in the step (2), the polarization sensor channel obtained according to the step (1)kResponse model ofV _k (Γ _k ) Are combined togethernChannel sensorThe response is solved for sensor measurement polarization information by using a least square method, whereinnNot less than 3, so as to reduce the influence of the measurement error of a certain channel on the accuracy of obtaining the polarization information, and the order is as follows:

i is light intensity and d is polarization degree;

writing a matrix form according to response models of all channels of the polarization sensor, wherein the matrix form comprises the following steps:

to obtainxLeast squares solution of (c):

polarization information and polarization sensor model multi-parameter vector gamma _k Of polarized light intensityI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Comprises the following steps:

so far, a mapping relation of polarization information on a multi-parameter vector gamma of a polarization sensor model is established: intensity of polarized lightI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Sqrt is a square root function.

4. The underwater polarization sensor multi-parameter optimization calibration method considering the dark current as claimed in claim 1, wherein:

in the step (3), the underwater time-varying light intensity environment is considered, and the polarized light intensity is establishedI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) The multi-parameter optimization function of (2):

objective optimization functionf(Γ _k ) In (1),outputting a measurement sequence of light intensity, a reference polarization azimuth angle and polarization degree for the integrating sphere;

the euclidean norm of the residual vector is used to establish the optimal estimate of the calibration coefficients as follows:

and calibrating the sensor under different light intensity conditions, and obtaining the optimal estimation of the sensor model coefficient by using a nonlinear least square method by taking the theoretical value of the sensor model parameter as an initial value.

5. The underwater polarization sensor multi-parameter optimization calibration method considering the dark current as claimed in claim 1, wherein:

in the step (4), the multi-parameter vector gamma of the polarization sensor model estimated in the step (3) is used _k Substituting pending polarization sensor response modelV _k (Γ _k ) Real-time polarized light intensity of simultaneous multi-channel sensor response solutionIAzimuth of polarizationAnd degree of polarizationd。

Technical Field

The invention belongs to the field of navigation equipment, and relates to a multi-parameter optimization calibration method for an underwater polarization sensor considering dark current, which considers the influence of dark current parameters and the like in the sensor on polarization resolving precision, can be used for perfecting a polarization sensor model, and improves the polarization information acquisition precision and the environmental adaptability of the polarization sensor in an underwater environment, particularly in an underwater weak light environment.

Background

The bionic polarization navigation is a novel navigation mode inspired by biology, has the advantages of being passive, free of radiation, good in autonomy, strong in anti-interference capability and the like, and has important significance for making up the defects of the existing underwater navigation technology, and the precision of a polarization sensor is a bottleneck problem limiting the application of underwater polarization navigation. The polarization sensor resolves polarization information by obtaining light intensity component responses of polarized light in different polarization directions, and the photosensitive chip is a core device for converting light intensity into current response. However, the polarization photosensitive chip has dark current errors, when the light intensity of the environment such as the atmosphere is strong, the dark current is relatively small and can be ignored, and under the environment with weak underwater light intensity, the dark current proportion is gradually increased, so that the polarization resolving accuracy and stability of the sensor are influenced.

In recent years, the research and application of the polarization sensor in the atmospheric environment are mature day by day, and a thesis of a course angle processing method based on a solenopsis POL-neuron model provides a polarization information resolving method of a six-channel polarization sensor without considering an error model under an ideal condition; the thesis 'bionic polarization sensor design based on a polarization beam splitter prism' designs an opposite channel polarization sensor based on the polarization beam splitter prism to be applied to an atmospheric environment so as to eliminate orthogonal errors of opposite channels; the patent 'a bionic polarization sensor multi-source error calibration method based on unscented Kalman filtering' (application number: 201810129371.8), mainly provides a measurement model aiming at model errors such as atmospheric environment analysis opposite type polarization sensor installation errors, diode response factors and the like, and provides a calibration compensation method. However, for an underwater environment, especially an underwater weak light environment, at present, research on the polarization sensor is not complete, and the dark current parameter of the polarization sensor directly affects the polarization information acquisition accuracy of the polarization sensor. Therefore, how to consider the dark current parameters to perfect the existing polarization sensor model and effectively calibrate the polarization sensor model to improve the underwater environment adaptability of the sensor is an urgent problem to be solved.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the existing polarization sensor does not consider the influence of dark current, so that the polarization resolving precision of the polarization sensor is low under different underwater light intensity environments; during the calibration process, the light intensity needs to be changed to obtain more accurate polarization sensor model parameters, and the calibration precision is not high only by taking the polarization azimuth angle as the calibration input. The method is based on a point source type opposite polarization sensor, aims at the problem that dark current ratio of a photosensitive chip of the polarization sensor is increased to cause output offset of each channel under the condition of weaker light intensity, considers dark current error to establish a sensor output mathematical model and a polarization information resolving method, establishes a target optimization function by utilizing light intensity, polarization azimuth angle and polarization degree error information, and finely calibrates parameters such as dark current of the polarization sensor under different light intensity conditions. The sensor can be suitable for application scenes with large underwater isocandela change, the polarization acquisition precision of the polarization sensor is improved, and the sensor has higher environmental adaptability.

The technical scheme of the invention is as follows: a multi-parameter optimization calibration method for an underwater polarization sensor considering dark current comprises the following implementation steps:

(1) due to the action of water surface refraction and water molecule scattering on light, the illumination intensity in an underwater scene is weaker than that in an atmospheric environment and is lower than 100 DEGlx. Dark current analysis for underwater low light environmentDInfluence mechanism and error transmission process on polarization sensor, and dark currentDThe response model of the polarization sensor channel of (1) a multi-parameter vector Γ _k Establishing a channel with respect to a polarization sensorkResponse model multi-parameter vector Γ _k Polarization sensor response modelV _k (Γ _k )；

(2) Obtained according to step (1)Polarization sensor channelkResponse modelV _k (Γ _k ) Are combined togethern(nNot less than 3) channel sensor responses obtaining polarization information by utilizing least square and regarding a multi-parameter vector gamma of a polarization sensor model _k The mapping relationship of (1): intensity of polarized lightI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k )；

(3) Establishing a polarization-based light intensity in consideration of an underwater time-varying light intensity environmentI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Model parameter vector Γ of _k Multiple parameter optimization function off(Γ _k ) Obtaining dark current by non-linear least square methodDThe polarization sensor model multi-parameter vector gamma _k Optimal estimation of (2);

(4) the multi-parameter vector gamma of the polarization sensor model estimated in the step (3) _k Substituting pending polarization sensor response modelV _k (Γ _k ) Real-time polarized light intensity of simultaneous multi-channel sensor response solutionIAzimuth of polarizationAnd degree of polarizationd。

The step (1) is specifically realized as follows:

dark currentDThe analysis of the influence mechanism of the polarization sensor is as follows:

from Malus law, firstiThe relationship between the current generated by each photosensitive chip and the incident polarized light is as follows:

wherein the content of the first and second substances,C _i is as followsiThe current is output by each light-sensing chip,K _Ii is as followsiThe light intensity response parameter of each light sensing chip,Iin order to input the light intensity,D _i is as followsiThe individual light sensing chips sense dark current.dIs the degree of polarization of the beam of light,in order to be the polarization azimuth angle,andis as followsiThe light intensity coefficient and the polarization degree coefficient caused by the extinction ratio error of the polaroid in the polarized light sensed by the photosensitive chip,the included angle between the installation position of the polaroid of the corresponding channel and the zero position of the sensor is formed.

The relation between the photosensitive chip and the incident polarized light can know that the input light intensity is in underwater environmentIThe weaker the output current of the photosensitive chipC _i Middle dark currentD _i The more the ratio, the effect is hardly negligible.

Opposite polarization sensor pass through oppositei、jThe output currents of the two photosensitive chips are subjected to logarithmic amplification operation, and the dark current error transmission process is analyzed, so that the dark current parameters of the opposite photosensitive chip are consideredD _i 、D _j The output of the polarization sensor channel of (a) is:

wherein the content of the first and second substances,Ka _k is a channelkThe amplification factor of the logarithmic amplifier is,V _OSOk is a channelkThe amplifier output is biased.

Building a channelkMulti-parameter polarization sensor model to be estimatedVector Γ _k Expressed as:

polarization sensor response modelV(Γ) is expressed as:

the step (2) is specifically realized as follows:

the polarization sensor channel obtained according to the step (1)kResponse model ofV _k (Γ _k ) Are combined togethern(n≥3) The response of each channel sensor solves the polarization information measured by the sensor by using a least square method so as to reduce the influence of the measurement error of a certain channel on the accuracy of obtaining the polarization information, and the order is as follows:

writing a matrix form according to response models of all channels of the sensor, wherein the matrix form comprises the following steps:

to obtainxLeast squares solution of (c):

polarization information and polarization sensor model multi-parameter vector gamma _k Of polarized light intensityI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Comprises the following steps:

so far, a mapping relation of polarization information on a multi-parameter vector gamma of a polarization sensor model is established: intensity of polarized lightI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Sqrt is a square root function.

The step (3) is specifically realized as follows:

considering underwater time-varying light intensity environment, establishing light intensity related to polarizationI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) The multi-parameter optimization function of (2):

objective optimization functionf(Γ _k ) In (1),a sequence of measurements of light intensity and reference polarization azimuth and degree of polarization is output for the integrating sphere.

The euclidean norm of the residual vector is used to establish the optimal estimate of the calibration coefficients as follows:

and calibrating the sensor under different light intensity conditions. And taking the theoretical value of the sensor model parameter as an initial value, and obtaining the optimal estimation of the sensor model coefficient by a nonlinear least square method.

The step (4) is specifically realized as follows:

substituting the multi-parameter vector gamma of the polarization sensor model estimated in the step (3) into a response model of the polarization sensor to be determinedV(gamma), simultaneous multi-channel sensor response resolving real-time polarized light intensityIAzimuth of polarizationAnd degree of polarizationd。

Compared with the prior art, the invention has the advantages that:

(1) the method overcomes the technical defect that the prior polarization sensor does not consider the influence of dark current on the navigation resolving precision of the sensor in the underwater weak light environment, provides a sensor model which considers the dark current of the sensor and is suitable for the underwater environment with different light intensity, and obtains the input light intensity by solving through least squareIDegree of polarizationdAnd azimuth of polarizationAnd dark currentDThe relationship of the sensor model parameters is equal;

(2) aiming at the problem of insufficient utilization of reference information in the existing calibration method, according to the relationship established by the invention based on dark current, light intensity and polarization information, a multi-parameter optimization function is established by using light intensity, polarization azimuth angle and polarization degree error information, more accurate estimation of a sensor model coefficient is obtained by a nonlinear least square method, and the resolving precision and stability of the polarization sensor are effectively improved.

Drawings

FIG. 1 is a flow chart of a multi-parameter optimization calibration method of an underwater polarization sensor considering dark current.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in fig. 1, the method for optimizing and calibrating multiple parameters of an underwater polarization sensor considering dark current comprises the following specific implementation steps:

(1) due to the action of water surface refraction and water molecule scattering on light, the illumination intensity in an underwater scene is weaker than that in an atmospheric environment and is lower than 100 DEGlx. Dark current analysis for underwater low light environmentDInfluence mechanism and error transmission process on polarization sensor, and dark currentDPolarization sensor channel ofkResponse model multi-parameter vector Γ _k Establishing a channel with respect to a polarization sensorkResponse model multi-parameter vector Γ _k Polarization sensor response modelV _k (Γ _k )；

(2) The polarization sensor channel obtained according to the step (1)kResponse modelV _k (Γ _k ) Are combined togethern(nNot less than 3) channel sensor responses obtaining polarization information by utilizing least square and regarding a multi-parameter vector gamma of a polarization sensor model _k The mapping relationship of (1): intensity of polarized lightI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k )；

(3) Establishing a polarization-based light intensity in consideration of an underwater time-varying light intensity environmentI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Model parameter vector Γ of _k Multiple parameter optimization function off(Γ _k ) Obtaining dark current by non-linear least square methodDThe polarization sensor model multi-parameter vector gamma _k Optimal estimation of (2);

(4) the multi-parameter vector gamma of the polarization sensor model estimated in the step (3) _k Substituting pending polarization sensor response modelV _k (Γ _k ) Real-time polarized light intensity of simultaneous multi-channel sensor response solutionIAzimuth of polarizationAnd degree of polarizationd。

The step (1) is specifically realized as follows:

dark currentDThe analysis of the influence mechanism of the polarization sensor is as follows:

from Malus law, firstiThe relationship between the current generated by each photosensitive chip and the incident polarized light is as follows:

wherein the content of the first and second substances,C _i is as followsiThe current is output by each light-sensing chip,K _Ii is as followsiThe light intensity response parameter of each light sensing chip,Iin order to input the light intensity,D _i is as followsiThe individual light sensing chips sense dark current.dIs the degree of polarization of the beam of light,in order to be the polarization azimuth angle,andis as followsiThe light intensity coefficient and the polarization degree coefficient caused by the extinction ratio error of the polaroid in the polarized light sensed by the photosensitive chip,the included angle between the installation position of the polaroid of the corresponding channel and the zero position of the sensor is formed.

The relation between the photosensitive chip and the incident polarized light can know that the input light intensity is in underwater environmentIThe weaker the output current of the photosensitive chipCMiddle dark currentDThe more the ratio, the effect is hardly negligible.

Opposite polarization sensor pass through oppositei、jThe output currents of the two photosensitive chips are subjected to logarithmic amplification operation, and the dark current error transmission process is analyzed, so that the dark current parameters of the opposite photosensitive chip are consideredD _i 、D _j Polarization sensor channel ofkThe output of (c) is:

wherein the content of the first and second substances,Ka _k is a channelkThe amplification factor of the logarithmic amplifier is,V _OSOk is a channelkThe amplifier output is biased.

Building a channelkMulti-parameter vector gamma of polarization sensor model to be estimated _k Expressed as:

polarization sensor response modelV(Γ) is expressed as:

the step (2) is specifically realized as follows:

according to the response model of the polarization sensor channel obtained in the step (1)V _k (Γ _k ) Are combined togethern(nNot less than 3) channel sensor responses, the sensor measurement polarization information is solved by using a least square method, so that the influence of a certain channel measurement error on the polarization information acquisition accuracy is reduced, and the order is as follows:

writing a matrix form according to response models of all channels of the sensor, wherein the matrix form comprises the following steps:

solving a least square solution:

polarization information and polarization sensor model multi-parameter vector gamma _k Of polarized light intensityI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Comprises the following steps:

so far, a mapping relation of polarization information on a multi-parameter vector gamma of a polarization sensor model is established: intensity of polarized lightI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) Sqrt is a square root function.

The step (3) is specifically realized as follows:

considering underwater time-varying light intensity environment, establishing light intensity related to polarizationI(Γ _k ) Azimuth of polarizationAnd degree of polarizationd(Γ _k ) The multi-parameter optimization function of (2):

objective optimization functionf(Γ _k ) In (1),a sequence of measurements of light intensity and reference polarization azimuth and degree of polarization is output for the integrating sphere.

The euclidean norm of the residual vector is used to establish the optimal estimate of the calibration coefficients as follows:

and calibrating the sensor under different light intensity conditions. And taking the theoretical value of the sensor model parameter as an initial value, and obtaining the optimal estimation of the sensor model coefficient by a nonlinear least square method.

The step (4) is specifically realized as follows:

the multi-parameter vector gamma of the polarization sensor model estimated in the step (3) _k Substituting pending polarization sensor response modelV _k (Γ _k ) Real-time polarized light intensity of simultaneous multi-channel sensor response solutionIAzimuth of polarizationAnd degree of polarizationd。

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but various changes may be apparent to those skilled in the art, and it is intended that all inventive concepts utilizing the inventive concepts set forth herein be protected without departing from the spirit and scope of the present invention as defined and limited by the appended claims.