KR101106048B1 - Method for calibrating sensor errors automatically during operation, and inertial navigation using the same - Google Patents

Abstract

The present invention relates to a method for automatically correcting an error of a sensor mounted on a vehicle for inertial navigation during operation of the vehicle and an apparatus using the method.
The inertial navigation device according to the present invention is an inertial navigation device that automatically corrects a sensor error of a moving object in operation, and includes an inertial sensor unit for measuring angular velocity and linear acceleration in a three-dimensional inertial space and outputting the measured information. Auxiliary sensor unit for detecting and outputting, a data storage unit for storing data used to calculate the correction coefficient between the operation and the inertial sensor unit receives the measurement information, using the auxiliary information to determine the error of the measurement information After estimating and compensating, the controller includes a controller configured to calculate a speed, a position, and a posture of the moving object based on the measured measurement information, wherein the controller uses the previously estimated error value during operation of the moving object. Calculate a correction coefficient between operations, use the calculated correction coefficient between operations in the error estimation, and the control unit Is a data storage portion and electrically connected to characterized in that the input and output information to it based on calculating the correction factor between the work.

Description

Automatic calibration method during operation of sensor error and inertial navigation system using it {METHOD FOR CALIBRATING SENSOR ERRORS AUTOMATICALLY DURING OPERATION, AND INERTIAL NAVIGATION USING THE SAME}

The present invention relates to an inertial navigation apparatus, and more particularly, to an automatic calibration method during operation of a sensor error and an inertial navigation apparatus using the same.

Inertial navigation system is a device that enables continuous navigation at high speed regardless of external environment by calculating navigation solution such as speed, position and attitude of moving object using inertial sensor. An inertial sensor consists of a gyroscope for measuring angular velocity in an inertial space and an accelerometer for measuring linear acceleration. The inertial navigation system calculates the navigation solution by integrating the output of the inertial sensor from the initial value. Therefore, the error of the inertial sensor is accumulated by the integration operation, and the error increases with time.

The performance of the inertial navigation system depends on the accuracy of the inertial sensor and the accuracy of the initial alignment. Initial alignment refers to the process of matching the reference coordinate axis of the inertial sensor with the navigation coordinate system.It is performed by comparing the angular velocity measured by the gyroscope and the acceleration measured by the accelerometer with the earth's rotational angular velocity and gravitational acceleration, respectively. . The initial alignment error is caused in proportion to the bias error, which is one of the errors of the inertial sensor.

Therefore, in order to increase the navigation performance of the inertial navigation system, accurate compensation must be made for the errors included in the inertial sensor such as gyroscope and accelerometer.

Errors of the inertial sensor are classified into fixed errors having a certain size regardless of movement, dynamic errors of varying in size according to movement, and random errors having irregular characteristics. Typical fixed errors include bias error, conversion factor error, and axis alignment error.

Fixed and dynamic errors except for random errors are known to be compensated through theoretical calibration tests. However, since dynamic errors are not large in size and difficult to compensate, generally only fixed errors are the target of compensation.

Error compensation of the inertial sensor is made through a calibration test. The calibration test is a series of procedures for calculating various calibration coefficients included in the error model of the inertial sensor using various methods such as estimation theory. The calibration test uses the output of the inertial sensor obtained through a multiposition test and a rate velocity test with temperature.

When the inertial navigation system can use external auxiliary sensors (e.g. GPS and speedometer) or auxiliary information (e.g. zero speed information, etc.), the inertial navigation device is a Kalman-filter which is an error estimator. ) Can be compensated by estimating the error of the inertial sensor in real time during operation. The error estimated here is the residual error remaining after compensating the calibration value of the inertial sensor. In order to estimate the error of the inertial sensor modeled on the Kalman filter, the observation conditions for the sensor error state variables such as acceleration and rotation of the moving body must be satisfied.

The inertial navigation system should maintain navigation performance even after long-term operation. However, as the inertial navigation system is operated for a long time, the characteristics of the inertial sensor change, and thus, there may be a difference between the correction coefficient and the actual error characteristic of the inertial sensor obtained at the time of initial manufacture. Therefore, there is a problem that the navigation performance of the inertial navigation apparatus is deteriorated by this difference.

Even in an inertial navigation system that compensates for sensor errors using Kalman filters, navigation errors, including initial alignment errors, occur largely until the observation conditions are satisfied and the error of the inertial sensors is estimated. In addition, in the above system, the estimation performance of the Kalman filter may be degraded because the error model of the Kalman filter and the actual error characteristic of the inertial sensor are different.

In order to compensate for such errors, recalibration of the inertial navigation apparatus is generally performed at a period of three to five years. The recalibration has a problem that requires a lot of time, manpower and cost, and also the operation of the inertial navigation system is limited during the recalibration period.

Accordingly, an object of the present invention is to solve the above problems.

Specifically, it is an object of the present invention to provide a method for calculating a new inter-operation calibration coefficient during operation of an inertial navigation system, compensating sensor errors using the new inter-operation calibration coefficient, and an inertial navigation apparatus using the method. .

In addition, an object of the present invention is to provide a method for continuously updating the correction coefficient between the operation by reflecting the change of the sensor error of the inertial navigation apparatus every operation, and an inertial navigation apparatus using such a method.

The inertial navigation device according to the present invention is an inertial navigation device that automatically corrects a sensor error of a moving object in operation, and includes an inertial sensor unit for measuring angular velocity and linear acceleration in a three-dimensional inertial space and outputting the measured information. Auxiliary sensor unit for detecting and outputting, a data storage unit for storing data used to calculate the correction coefficient between the operation and the inertial sensor unit receives the measurement information, using the auxiliary information to determine the error of the measurement information After estimating and compensating, the controller includes a controller configured to calculate a speed, a position, and a posture of the moving object based on the measured measurement information, wherein the controller uses the previously estimated error value during operation of the moving object. Calculate a correction coefficient between operations, use the calculated correction coefficient between operations in the error estimation, and the control unit Is a data storage portion and electrically connected to characterized in that the input and output information to it based on calculating the correction factor between the work.

Preferably, the data storage unit includes a sensor error estimation value, the control unit, the operation coefficient between the operation coefficient correction unit for calculating the correction coefficient between the operation based on the sensor error estimation value received from the data storage unit, between the operation An inertial sensor error compensator for compensating for the error of the measurement information received from the inertial sensor unit based on the inter-operation calibration coefficient received from the calibration coefficient estimator, and the error received from the inertial sensor error compensator is compensated for The inertial navigation calculator calculates the speed, position, and attitude of the moving object based on the measured information, and the speed, position, attitude, and error compensation information received from the auxiliary sensor unit. An error estimating Kalman filter unit for calculating the sensor error estimation value based on the error estimate Perform the necessary processing on the sensor error estimation value received from the Kalman filter unit, and the sensor error estimation value is characterized in that it comprises an automatic calibration, the data processing between the operation of storing in the data storage unit.

Preferably, the data storage unit further includes automatic calibration state information and a calibration coefficient between immediately preceding operations, and the inter-operation automatic calibration data processing unit normalizes or abnormalizes the automatic calibration state information according to the accuracy and reliability of the sensor error estimation value. The calibration coefficient estimator may be configured to use the last inter-operation calibration coefficient as the calculated inter-operation calibration coefficient when the automatic calibration state information is abnormal, and to determine the inter-calibration calibration coefficient when the automatic calibration state information is normal. After the calculation, the calculated correction coefficient between the operation is characterized in that stored in the data storage.

Preferably, the setting of the automatic calibration state information to be abnormal may include: whether or not the initial alignment performed by the inter-operation automatic calibration data processing unit is not completed, and a part of the Kalman filter inspected by the inter-operation automatic calibration data processing unit. Whether the covariance among the state variables does not converge and the cumulative variance for each of the sensor error estimates calculated by the inter-operation automatic calibration data processor is not less than a predetermined threshold value for each sensor error estimate. It is characterized by using one or more of the criteria as a criterion.

Preferably, the data storage unit further includes a previous estimated number N, and the sensor error estimates of the data storage unit are N estimated values generated by N operations immediately before the automatic calibration data processing unit between the operations, and the operation The inter-correction coefficient estimator calculates the inter-operation correction coefficient based on the N sensor error estimates, and the inter-operation correction coefficient is an average of the N sensor error estimates.

Preferably, the data storage unit further includes a previous inter-operation correction coefficient, and the inter-operation correction coefficient estimator checks the validity of each of the sensor error estimates and, if any of the sensor error estimates are invalid, operates the immediately preceding operation. The inter-correction coefficient is used as the calculated inter-operation correction coefficient, and when all of the sensor error estimates are valid, the calculated inter-operation correction coefficient is stored in the data storage unit after the calculation of the inter-operation correction coefficient.

Preferably, the sensor error estimate value is effective when the difference between the respective sensor error estimate value and the correction coefficient between the immediately preceding operation with respect to the sensor error estimate value is within a range of a predetermined determination reference value for the sensor error estimate value.

In the method of automatically calibrating the sensor error of the moving object during operation of the sensor error according to the present invention, the step of receiving the angular velocity and linear acceleration measurement information in the three-dimensional inertial space, the correction coefficient between the operation Compensating the error of the measurement information based on, Computing the speed, position, attitude of the moving object on the basis of the measurement information is compensated for the error, Receiving information for compensating the error of the measurement information And recalculating the inter-operation correction coefficient based on the calculated speed, position, attitude, and the error compensation information, wherein the re-calculated inter-operation correction coefficient compensates for the error of the measurement information. It is characterized by the application.

Preferably, the step of recalculating the inter-operation correction coefficient, generating a sensor error estimate using a Kalman filter based on the calculated speed, position, attitude and the error compensation information, for the sensor error estimate Performing the necessary processing and storing the sensor error estimate and associated information and calculating the calibration factor between operations based on the stored sensor error estimate and associated information.

The present invention provides a method for compensating for a sensor error during operation of an inertial navigation device and an inertial navigation device using the method. The inertial navigation apparatus does not require a separate recalibration procedure, and navigation performance can be maintained even when operated for a long time.

Therefore, the recalibration requires a lot of time, manpower and cost, and solves the problem of the prior art that the operation of the inertial navigation apparatus is limited.

In addition, since the inertial navigation apparatus continuously updates the change of the sensor error at every operation, it solves the problem of the prior art that the navigation performance is lowered when the error characteristic is changed compared to the initial calibration value.

1 is a block diagram of an inertial navigation apparatus according to an embodiment of the present invention.
2 is a diagram illustrating information stored in a data storage unit according to an embodiment of the present invention.
Figure 3 is a flow chart of the operation coefficient between the correction coefficient estimation unit according to an embodiment of the present invention.
Figure 4 is a flow chart of the operation between the correction coefficient data processing unit according to an embodiment of the present invention.

The present invention is applied to an inertial navigation using a Kalman filter and an inertial navigation apparatus using the same. However, the present invention is not limited thereto and may be applied to an electronic device and a method related thereto, to which the technical spirit of the present invention may be applied.

It is to be noted that the technical terms used herein are merely used to describe particular embodiments, and are not intended to limit the present invention. It is also to be understood that the technical terms used herein are to be interpreted in a sense generally understood by a person skilled in the art to which the present invention belongs, Should not be construed to mean, or be interpreted in an excessively reduced sense. In addition, when the technical terms used herein are incorrect technical terms that do not accurately express the spirit of the present invention, they should be replaced with technical terms that can be understood correctly by those skilled in the art. In addition, the general terms used in the present invention should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted in an excessively reduced sense.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In the present application, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various components, or various steps described in the specification, wherein some of the components or some of the steps It should be construed that it may not be included or may further include additional components or steps.

In addition, terms including ordinal numbers, such as first and second, as used herein may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in between. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In addition, in describing the present invention, when it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easily understanding the spirit of the present invention and should not be construed as limiting the spirit of the present invention by the accompanying drawings. The spirit of the present invention should be construed to extend to all changes, equivalents, and substitutes in addition to the accompanying drawings.

1 is a block diagram of an inertial navigation apparatus according to an embodiment of the present invention.

The inertial navigation apparatus includes an inertial sensor unit 110, an auxiliary sensor unit 120, a data storage unit 130, and a controller 140.

The inertial sensor unit 110 measures the angular velocity and the linear acceleration in the three-dimensional inertial space and outputs the measured information.

The inertial sensor unit 110 may include three gyroscopes for measuring angular velocity, three accelerometers for measuring acceleration, and a processor. The processor processes a sensor signal output by each sensor in the inertial sensor unit. In addition, the processor may compensate the sensor signal based on a calibration coefficient calculated through a calibration test.

The auxiliary sensor unit 120 may include a GPS, a speedometer, or a zero speed information measuring device. The auxiliary sensor unit 120 detects and outputs auxiliary information.

The data storage unit 130 stores data based on the calculation of the calibration coefficients between operations.

The controller 140 is electronically or electrically connected to the inertial sensor unit 110 and the auxiliary sensor unit 120 to input information output from the inertial sensor unit 110 and the auxiliary sensor unit 120. Receive. In addition, the controller 140 is electronically connected to the data storage 130 to enable input and output of data.

The control unit 140 compensates for the error of the measurement information received from the inertial sensor unit 110 using the correction coefficient between operations, and based on the measured information for which the error is compensated, the speed, position, and posture of the moving object in operation. And rotation and the like.

In addition, the control unit 140 recalculates the correction coefficient between the operations based on the calculated inertial navigation and the error compensation information received from the auxiliary sensor unit 120. The recalculated inter-operation correction coefficient is applied in real time when the controller 140 next calculates the inertial navigation.

The control unit 140 is an operation correction coefficient estimation unit 150, an inertial sensor error compensation unit 160, an inertial navigation calculation unit 170, an error estimation Kalman filter unit 180, an automatic operation data correction unit 190 ). Each of the components 150, 160, 170, 180, and 190 of the controller 140 may be independent hardware such as a control chip. In addition, the components 150, 160, 170, 180, and 190 may refer to independent processes running on a processor, and may be threads or modules within a process.

The inter-operation correction coefficient estimator 150 calculates the inter-operation correction coefficient based on the sensor error estimation value and the like stored in the data storage unit 130.

The inter-operation calibration coefficient estimator 150 outputs the calculated inter-operation calibration coefficient, and the inter-operation calibration coefficient is used as an initial value in the inertial sensor error compensator 160.

The calibration coefficient estimation unit 150 may be operated first after the power of the inertial navigation apparatus is applied.

The inertial sensor error compensation unit 160 receives the measurement information output from the inertial sensor unit 110 as an input. In addition, the inertial sensor error compensator 160 compensates the error of the measurement information based on the inter-operation calibration coefficient received from the inter-operation calibration coefficient estimator 150. The inertial sensor error compensator 160 outputs measurement information with the error compensated.

The inertial sensor error compensator 160 may receive a sensor error estimation value updated in real time output from the error estimation Kalman filter unit 180 to compensate for the error of the measurement information based on the sensor error estimate value.

The inertial navigation calculator 170 calculates inertial navigation information of the moving object based on the measured information compensated for the error output from the inertial sensor error compensator 160, and outputs the calculated inertial navigation information. . The inertial navigation information may include the speed, position and attitude of the moving object.

The Kalman filter of the error estimation Kalman filter unit 180 uses an external auxiliary sensor (for example, GPS and speedometer, etc.) or auxiliary information (for example, zero speed information) to calibrate the inertial sensor during operation. Compensate the value and estimate the remaining surplus error in real time.

That is, the error estimation Kalman filter unit 180 calculates a sensor error estimation value based on the error compensation information output from the auxiliary sensor unit 120 and the inertial navigation information output from the inertial navigation calculator 170. And outputs the sensor error estimation value.

The sensor error estimation value may be input to the inertial sensor error compensator 160 and used to compensate an error of the measurement information in real time.

The automatic calibration data processing unit 190 receives the sensor error estimation value from the error estimation Kalman filter unit 180, performs the necessary processing so that the sensor error estimation value can be used for automatic calibration between operations, and performs the sensor error estimation value. The data storage unit 130 stores the data.

The necessary processing includes determining the accuracy and reliability of the sensor error estimate.

The automatic calibration data processor 190 may operate in the same operation cycle as the error estimation Kalman filter unit 180.

2 illustrates information stored in the data storage unit 130 according to an embodiment of the present invention.

The data storage unit stores the sensor error estimation value 240. The sensor error estimate may include a gyro bias estimate 241, a gyro conversion factor estimate 242, an accelerometer bias estimate 243, an accelerometer conversion factor estimate 244, and a speedometer error estimate 245.

The gyro bias estimate 241 stores an estimate of the gyro bias error for the x, y and z axes. The gyro conversion coefficient estimate 242 stores an estimate of gyro conversion coefficient errors for the x, y, and z axes. The accelerometer bias estimate 243 stores an estimate of the accelerometer bias error for the x, y, and z axes. The accelerometer conversion coefficient estimate 244 stores an estimate of the accelerometer conversion coefficient errors for the x, y, and z axes. The speedometer error estimate 245 stores an estimate of conversion factor error and unalignment error of the speedometer.

The sensor error estimation value 240 may be a plurality of measurement values measured immediately before N times, respectively. In this case, the number N is stored in the data storage 130 as the previous estimated number 220.

The data storage unit 130 may include automatic calibration state information 210 and a calibration coefficient 230 between immediately preceding operations.

The automatic calibration state information 210 is set to normal or abnormal according to the accuracy and reliability of the sensor error estimation value in the previous operation. The automatic calibration state information 210 is stored by the inter-operation automatic calibration data processing unit 190 and used by the inter-operation calibration coefficient estimator 150.

The automatic calibration state information 210 may include whether the error estimation Kalman filter unit 180 operates normally.

The automatic calibration state information 210 may include whether the sensor error estimation value is estimated to be normal 212.

The automatic calibration state information 210 may include whether the speedometer of the auxiliary sensor unit is interlocked.

The inter-operation correction coefficient 230 is stored in the last operation correction coefficient calculated by the operation correction coefficient estimation unit 150 is stored. The last inter-operation calibration coefficient 230 is a newly calculated inter-operation calibration when the auto-calibration state information 210 is abnormal and the inter-operation calibration coefficient estimator 150 cannot newly calculate the inter-operation calibration coefficient. Used as a factor.

Hereinafter, the operation of the calibration coefficient estimator 150 between operations according to an embodiment of the present invention will be described.

3 is an operation flowchart of the calibration coefficient estimator 150 between operations according to an exemplary embodiment of the present invention.

First, the inter-operation calibration coefficient estimator 150 reads data necessary for automatic calibration from the data storage 130 (S300).

Next, the inter-operation calibration coefficient estimator 150 checks the validity of the automatic calibration state information (S310). The check is to check whether the automatic calibration status information 210 is recorded as valid. The automatic calibration state information 210 is recorded by the automatic calibration data processor 190 between the operations.

If the result of the inspection is abnormal, the previous sensor error estimation value cannot be trusted to be accurate, so the inter-operational calibration coefficient estimator 150 uses the previous inter-operational calibration coefficient 230 again as the newly calculated calibration coefficient ( S350), the procedure ends.

If the result of the inspection is normal, the inter-operation calibration coefficient estimator 150 checks the validity of the sensor error estimation value 240 (S320). If the sensor error estimate 240 is the previous N estimates, the immediately previous sensor error estimate is the target of inspection.

The validity check of the sensor error estimate 240 compares the magnitude of each of the sensor error estimates 240 241, 242, 243, 244 or 245 with the magnitude of the last-correction correction factor 230, thereby estimating the sensor error estimate. 240 is to validate the validity of each of 241, 242, 243, 244 or 245.

The validity of each of the sensor error estimation values 240, 241, 242, 243, 244 or 245 is checked using Equation 1 below.

here,

_i is a number that identifies each sensor error. i has a value from 1 to the number of sensor errors that are subject to calibration between operations. The sensor error may include a gyro bias error, a gyro conversion error, an accelerometer bias error, and a conversion error with respect to the x, y, and z axes, and may include a conversion factor error and an unalignment error of the speedometer.

x _i means the sensor error estimate (241, 242, 243, 244 or 245) for the i-th sensor error, x _i (k-1) is the previous sensor error estimate (241, 242, 243, 244 or 245) ).

X _i denotes the calibration factor between operations for the i-th sensor error. X _i (k-1) means the correction factor between the previous operations.

THR1 _i denotes a criterion of the validity test for the i-th sensor error.

That is, when the equation 1 is satisfied for each of the sensor error estimates 241, 242, 243, 244 and 245, the sensor error estimate is valid. If any of the respective sensor error estimates 241, 242, 243, 244 or 245 is invalid, the immediately preceding sensor error estimate cannot be trusted to be correct. Therefore, the inter-operational calibration coefficient estimator 150 uses the immediately previous inter-operational calibration coefficient 230 as a newly calculated calibration coefficient (S350), and the procedure ends.

When the two conditions are satisfied, that is, when the automatic calibration state information is normal and the immediately preceding sensor error is valid, the inter-operation calibration coefficient estimator 150 uses the previous N error estimates of the sensor 220. Calculate the calibration coefficient between the new operation (S330).

The new inter-operation correction coefficient can be calculated by Equation 2 below.

That is, for each sensor error, the average of the immediately preceding N sensor error estimates is calculated.

After calculation, the inter-operational calibration coefficient estimator 150 stores the newly calculated inter-operational calibration coefficient in the data storage 130 as the last inter-operational calibration coefficient 230, and stores the inter-operational calibration coefficient. Output

Hereinafter, the operation of the automatic calibration data processor 190 between the operations according to an embodiment of the present invention will be described.

4 is an operation flowchart of the correction coefficient data processing unit 190 between operations according to an embodiment of the present invention.

First, the inter-operation automatic calibration data processor 190 determines whether initial alignment has been completed. If the initial alignment is not completed, the automatic calibration state information setting step S430 is performed.

Next, the automatic calibration data processor 190 during the operation checks the covariance convergence of the Kalman filter. The covariance of the Kalman filter has a characteristic of converging to zero when the state variable of the filter is estimated, that is, under the observed conditions. Therefore, the accuracy of the sensor error estimation value can be determined using the convergence characteristic of the covariance value.

The convergence of the covariance can be determined using Equation 3 below.

here,

P _i is the covariance of the i state variable,

THR2 _i is the reference value of the i-th state variable covariance.

The convergence of the covariance can be checked for all state variables. However, preferably the convergence of the covariance can only be checked for important variables for efficiency. The important variable may refer to a state variable that best represents an operation state and an estimation possibility of the Kalman filter in a movement environment such as stopping, accelerating, and changing posture of a moving object. The state variables may include azimuth error, x-axis gyro bias error, y-axis gyro bias error, x-axis accelerometer bias error, and y-axis accelerometer bias error.

If the covariance of all the state variables subjected to the test satisfies the condition of Equation 3, it may be determined that the covariance is normally converged. If it is determined that the covariance is not normally converged, the automatic calibration state information setting step S430 is performed.

When the initial alignment test (S400) and the covariance convergence test (S410) are satisfied, the inter-operation automatic calibration data processing unit 190 calculates the cumulative average and variance of the sensor error estimation value (S420). The cumulative average value is a representative value of the sensor error estimation values estimated during operation, and the variance value is a value that is a reference for evaluating the reliability of the sensor error estimation value.

The cumulative average and the variance may be calculated as in Equation 4 below.

here,

J is the cumulative number of data,

x _i (j) is the j th estimate of sensor error x _i ,

μ _i (j) is the j-th cumulative mean of sensor error x _i ,

σ _i (j) is the j-th cumulative variance of the sensor error x _i .

Next, the automatic calibration data processor 190 sets the automatic calibration status information value (S430).

The automatic calibration state information value includes a normal operation value of the Kalman filter. The normal operation value of the Kalman filter may be set to normal when the initial alignment test 400 is completed and the result of the covariance convergence test (S410) is normal, otherwise, it may be set to abnormal.

The automatic calibration state information includes a normal estimation value of the sensor error. Whether the sensor error is normally estimated is determined by Equation 5 below.

here,

THR3 _i means a reference value for the cumulative dispersion value of the i-th sensor error.

That is, when the cumulative dispersion value of each sensor error estimation value is less than or equal to the reference value, whether the sensor error is normally estimated is set to normal.

Next, the automatic calibration data processor 190 stores the sensor error estimation value and the automatic calibration state information value in the data storage 130 (S440). The automatic calibration status information value may be recorded in the automatic calibration status information 210 of the data processor 190. The sensor error estimate may be recorded in the sensor error estimate 240 of the data processor 190.

The method according to the invention described thus far can be implemented in software, hardware, or a combination thereof. For example, the method according to the present invention may be stored in a storage medium (eg, mobile terminal internal memory, flash memory, hard disk, etc.) and may be stored in a processor (eg, mobile terminal internal microprocessor). It may be implemented as codes or instructions in a software program that can be executed by.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, May be modified, modified, or improved.

Claims (9)

In the inertial navigation system that automatically corrects the sensor error of the moving object,
An inertial sensor unit for measuring angular velocity and linear acceleration in a three-dimensional inertial space and outputting measurement information;
An auxiliary sensor unit for detecting and outputting auxiliary information;
A data storage for storing data used to calculate a calibration coefficient between operations; And
After receiving the measurement information from the inertial sensor unit, using the auxiliary information to estimate and compensate for the error of the measurement information, and calculates the speed, position and attitude of the moving object on the basis of the measurement information compensated for the error Including a control unit,
The control unit calculates an inter-operation correction coefficient using an error value previously estimated during operation of the moving object, and uses the calculated inter-operation correction coefficient in the error estimation, and the control unit electronically with the data storage unit. Connected to input and output the information that is the basis for calculating the correction coefficient between operations,
The data storage unit includes a sensor error estimate value,
The control unit,
An inter-operation calibration coefficient estimator configured to calculate the inter-operation calibration coefficient based on the sensor error estimation value received from the data storage unit;
An inertial sensor error compensator for compensating for an error of the measurement information received from the inertial sensor unit based on the inter-operation correction coefficient received from the inter-operation calibration coefficient estimator;
An inertial navigation calculator configured to calculate a speed, a position, and an attitude of the moving object on the basis of the measured information compensated for by the error inputted from the inertial sensor error compensator;
An error estimation Kalman filter unit calculating the sensor error estimation value based on the speed, position, attitude, and the error compensation information received from the auxiliary sensor unit; And
And an automatic calibration data processing unit for performing the necessary processing on the sensor error estimation value received from the error estimation Kalman filter unit and storing the sensor error estimation value in the data storage unit. delete The method of claim 1,
The data storage unit further includes the automatic calibration state information and the correction coefficient between the last operation,
The automatic calibration data processor between operations sets the automatic calibration state information to normal or abnormal according to the accuracy and reliability of the sensor error estimation value.
The inter-operational calibration coefficient estimator uses the last inter-operational calibration coefficient as the calculated inter-operational calibration coefficient when the automatic calibration state information is abnormal, and calculates the inter-operational calibration coefficient when the automatic calibration state information is normal. An inertial navigation device, characterized in that for storing the calculated correction coefficient between the operation to the data storage. The method of claim 3, wherein
Setting the autocalibration status information abnormally includes whether or not an initial alignment performed by the autocalibration data processing unit between operations is not completed, and some state variables of the Kalman filter inspected by the autocalibration data processing unit between operations. Whether the covariance does not converge and whether the cumulative variance for each of the sensor error estimates calculated by the inter-operation automatic calibration data processing unit is less than a predetermined reference value for each sensor error estimate. Inertial navigation apparatus, characterized in that one or more as a criterion. The method of claim 1,
The data storage unit further includes a previous estimated number N,
The sensor error estimates of the data storage unit are N estimated values generated by the previous N operations of the automatic calibration data processing unit between the operations,
The inter-operational calibration coefficient estimator calculates the inter-operational calibration coefficients based on the N sensor error estimates,
And said calibration coefficient between operations is an average of said N sensor error estimates. The method of claim 1,
The data storage unit further includes a correction factor between immediately preceding operations,
The inter-operation calibration coefficient estimator checks the validity of each of the sensor error estimates, and if any of the sensor error estimates is invalid, uses the immediately previous operation calibration coefficient as the calculated inter-operation calibration coefficient, and the sensor error. And if the estimated values are valid, after the calculation of the inter-operation calibration coefficients, the calculated in-operation calibration coefficients are stored in the data storage unit. The method of claim 6,
And the sensor error estimate value is valid when the difference between the respective sensor error estimate value and the correction coefficient between the immediately preceding operation with respect to the sensor error estimate value is within a range of a predetermined determination reference value for the sensor error estimate value. delete delete

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