An online calibration method for odometer parameters and a storage medium

Abstract

The present invention relates to the field of measurement technologies, and more particularly, to an online calibration method for odometer parameters and a storage medium. The calibration method includes using the position of the carrier during the first mileage as the starting point, and using the position of the carrier during the second mileage as the ending point, where the second mileage is the mileage that the carrier travels after traveling the first mileage; obtaining the first position information of the carrier at the starting point; obtaining the second position information of the carrier at the ending point; obtaining the first odometer parameters of the carrier based on the first position information and the second position information; obtaining the second odometer parameters of the carrier based on the preset odometer parameters of the carrier and the first odometer parameters; and obtaining the target odometer parameters of the carrier when the variation between the second odometer parameters and the preset odometer parameters is within a preset range. The method of the present invention is simple and easy to implement, and the accuracy of the odometer parameter calibration result is improved by the method of the present invention.

Description

Technical Field

[0001] The present invention relates to the technical field of measurement, and more particularly, to an online calibration method for odometer parameters and a storage medium. Background Art

[0002] A positioning and orientation system composed of an inertial navigation system, a satellite navigation system, an odometer, and an altimeter realizes navigation and positioning through a multi-information fusion method. To ensure the high-precision attitude, speed, and position output of the positioning and orientation device, odometer parameters (scale factor error, heading installation offset angle, pitch installation offset angle) need to be calibrated before use. Currently, the commonly used odometer parameter calibration methods for positioning and orientation systems include landmark (high-precision position reference, road mark) calibration methods and filtering calibration methods. For landmark calibration: high-precision position references are expensive, and there is a risk that road marks will be occupied; for the filtering calibration method: a complex filtering model needs to be established, and the calibration effect is not ideal when the model is inaccurate and external information is inaccurate, and a certain amount of vehicle maneuvering is required.

[0003] In the existing odometer calibration technology, one method calculates the vehicle position using a dead reckoning method after the positioning and orientation system completes initial alignment. After the vehicle travels a certain distance to reach a specified position, the odometer parameters are calibrated using relevant calculation methods by using the high-precision position reference or the position value of the road mark at the specified position. This method has problems such as high cost, time-consuming disassembly and assembly of the position reference system, and the influence of the road mark position on the surrounding environment; another method is to establish a filtering calibration model related to the odometer parameters, and the odometer parameters are calibrated by introducing external information and using filtering technology. This method has problems such as inaccurate establishment of the filtering model, inaccurate external information, and a long parameter adjustment period. Summary of the Invention

[0004] To solve at least one problem in the background art, the present invention provides an online calibration method for odometer parameters and a storage medium.

[0005] According to a first aspect of the present invention, there is provided an online calibration method for odometer parameters, including the following steps:

[0006] Taking the position of the vehicle during the first mileage as the starting point and the position of the vehicle during the second mileage as the end point, where the second mileage is the mileage that the vehicle travels after traveling the first mileage;

[0007] Obtaining first position information of the vehicle at the starting point, where the first position information includes the first satellite navigation output position of the starting point, the first dead reckoning position, and the first travel distance of the starting point relative to the first starting point among the starting points;

[0008] Obtain the second position information of the carrier at the end point, where the second position information includes the second satellite navigation output position, the second dead reckoning position of the end point, and the second driving distance of the end point relative to the first starting point among the starting points;

[0009] Obtain the first odometer parameter of the carrier according to the first position information and the second position information;

[0010] Obtain the second odometer parameter of the carrier according to the preset odometer parameter of the carrier and the first odometer parameter;

[0011] Obtain the target odometer parameter of the carrier according to that the variation between the second odometer parameter and the preset odometer parameter is within a preset range.

[0012] According to an embodiment of the present invention, there are i starting points in the first mileage of the carrier, where i is a natural number and i≥1;

[0013] There are j end points in the second mileage of the carrier, where j is a natural number and j≥i;

[0014] The mileages of the i starting points are all different;

[0015] The mileages of the j end points are all different.

[0016] According to an embodiment of the present invention, among the i starting points, the mileage between adjacent starting points is C1;

[0017] Among the j end points, the mileage between adjacent end points is C2;

[0018] Where C1 and C2 are natural numbers, C1>0, C2>0;

[0019] The C2 is the same as or different from the C1.

[0020] According to an embodiment of the present invention, according to that the carrier travels an additional mileage of C3 relative to the last starting point in the first mileage, obtain the first end point in the second mileage;

[0021] Among the mileages that the carrier travels relative to the first end point, obtain the other end points among the j end points;

[0022] Where C3 is a natural number, C3>C1, and C3>C2.

[0023] According to an embodiment of the present invention, the satellite navigation output position includes a first longitude, a first latitude, and a first altitude; the dead reckoning position includes a second longitude, a second latitude, and a second altitude.

[0024] According to an embodiment of the present invention, based on the first satellite navigation output position, the first dead reckoning position, the first travel distance of the starting point relative to the first starting point among the starting points, the second satellite navigation output position, the second dead reckoning position, and the second travel distance of the end point relative to the first starting point among the starting points, obtain the true displacement vector, the dead reckoning displacement vector, the travel mileage, and the elevation error of the end point;

[0025] Obtain the first odometer parameter according to the true displacement vector, the dead reckoning displacement vector, the travel mileage, and the elevation error; the first odometer parameter includes a scale factor error, a heading installation offset angle error, and a pitch installation offset angle error.

[0026] According to an embodiment of the present invention, the preset odometer parameter includes a preset scale factor, a preset heading installation offset angle, and a preset pitch installation offset angle;

[0027] Obtain the second odometer parameter according to the scale factor error, the heading installation offset angle error, the pitch installation offset angle error, the preset scale factor, the preset heading installation offset angle, and the preset pitch installation offset angle;

[0028] The second odometer parameter includes a calculated scale factor, a calculated heading installation offset angle, and a calculated pitch installation offset angle.

[0029] According to an embodiment of the present invention, the change amount between the second odometer parameter and the preset odometer parameter being less than the preset range includes:

[0030] The change amount between the calculated scale factor in the second odometer parameter and the preset scale factor in the preset odometer parameter is less than the preset range.

[0031] According to an embodiment of the present invention, after the change amount between the second odometer parameter and the preset odometer parameter is within the preset range, when there are i starting points and i>1, where i is a natural number, obtain the second odometer parameters that the carrier has relative to the i starting points respectively when located at the end point, and perform an accumulation and averaging process on the i second odometer parameters to obtain the target odometer parameter.

[0032] According to an embodiment of the present invention, when there are i starting points, j end points, and i>1 and j>1, where i and j are natural numbers, obtain the second odometer parameters that the carrier has relative to the i starting points respectively when located at the j end points, and perform an accumulation and averaging process on the i second odometer parameters that the j end points have respectively to obtain the target odometer parameter.

[0033] According to an embodiment of the present invention, the cumulative averaging process of the second odometer parameter includes:

[0034] Accumulate the calibration results of the estimated scale factor to obtain the target scale factor in the target odometer parameter;

[0035] Accumulate the calibration results of the estimated heading installation offset angle to obtain the target heading installation offset angle in the target odometer parameter;

[0036] Accumulate the calibration results of the estimated pitch installation offset angle to obtain the target pitch installation offset angle in the target odometer parameter.

[0037] According to the second aspect of the present invention, the present invention provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0038] The present invention has the following beneficial effects:

[0039] By designing reasonable starting and ending points of the carrier, the present invention realizes stable and reliable online calibration of odometer parameters by using the preset range determination and statistical calculation method, and can automatically update and store the latest calibration results, avoiding the problems that the calibration scheme requires landmark points or the filtering method requires the carrier to maneuver and avoiding inaccurate models and inaccurate external information. Through the odometer parameter calibration method of the present invention, the calibration method is simple and easy to implement, which can not only improve the accuracy of the calibration results, but also improve the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Shows a flowchart of the online calibration method for odometer parameters of the present invention;

[0041] Figure 2 Shows a schematic diagram of the online calibration path for odometer parameters of the present invention. DETAILED DESCRIPTION

[0042] Now the content of the present disclosure will be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those of ordinary skill in the art to better understand and thus implement the content of the present disclosure, rather than implying any limitation to the scope of the present disclosure.

[0043] As used herein, the term "comprising" and its variants are to be construed as open-ended terms meaning "including but not limited to". The term "based on" is to be construed as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be construed as "at least one embodiment". The term "another embodiment" is to be construed as "at least one other embodiment". The terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "a plurality of" means two or more.

[0044] This embodiment discloses an online calibration method for odometer parameters, as Figure 1 shown, including the following steps:

[0045] Taking the position of the carrier during the first mileage as the starting point and the position of the carrier during the second mileage as the ending point, where the second mileage is the mileage that the carrier travels after traveling the first mileage;

[0046] Obtaining first position information of the carrier at the starting point, where the first position information includes the first satellite navigation output position, the first dead reckoning position of the starting point, and the first travel distance of the starting point relative to the first starting point among the starting points;

[0047] Obtaining second position information of the carrier at the ending point, where the second position information includes the second satellite navigation output position, the second dead reckoning position of the ending point, and the second travel distance of the ending point relative to the first starting point among the starting points;

[0048] Obtaining the first odometer parameter of the carrier according to the first position information and the second position information;

[0049] Obtaining the second odometer parameter of the carrier according to the preset odometer parameter and the first odometer parameter of the carrier;

[0050] Obtaining the target odometer parameter of the carrier when the change amount between the second odometer parameter and the preset odometer parameter is within a preset range.

[0051] In this embodiment, the method for obtaining position information does not require an external position reference or waypoints, achieving fully autonomous calibration of the odometer parameters of the positioning and orientation system. The satellite navigation is a satellite receiver, and there is no absolute high-precision requirement for the position information provided by the satellite receiver, improving work efficiency. By the method that the variation between the second odometer parameters and the preset odometer parameters is within a preset range, unreasonable calibration results can be automatically eliminated, improving the accuracy of the calibration results. Through the odometer parameter calibration method of the present invention, the calibration method is simple and easy to implement, which can not only improve the accuracy of the calibration results, but also improve work efficiency.

[0052] In some embodiments, the preset odometer parameters in the carrier are updated to the obtained target odometer parameters, realizing automatic update and storage of the odometer parameters, and being applied in actual projects. Through the method of this embodiment, the latest calibration results can be automatically updated and stored, avoiding the problems that the calibration scheme requires landmark points or the filtering method requires the carrier to maneuver and avoiding inaccurate models and inaccurate external information.

[0053] According to an embodiment of the present invention, the carrier has i starting points in the first odometer, where i is a natural number and i≥1;

[0054] The carrier has j end points in the second odometer, where j is a natural number and j≥i;

[0055] The odometers of the i starting points are all different;

[0056] The odometers of the j end points are all different.

[0057] In this embodiment, the carrier has i starting points in the first odometer, that is, the carrier stops i times in the first odometer. Taking the position where the carrier stops each time in the first odometer as the starting point, the carrier has i starting points. The carrier has j end points in the second odometer, that is, the carrier stops j times in the second odometer. Taking the position where the carrier stops each time in the second odometer as the end point, the carrier has j end points. This embodiment makes full use of the existing equipment of the positioning and orientation system. By designing reasonable starting points and end points and adopting a preset range determination and statistical calculation method, stable and reliable online calibration of the odometer parameters is realized.

[0058] In some embodiments, i≥3 and j≥5. This ensures the accuracy of the calibration results.

[0059] Preferably, as Figure 2 shown, i = 3 and j = 5. This reduces the calibration time and improves work efficiency while ensuring the accuracy of the calibration results.

[0060] In some embodiments, when there are i starting points in the first mileage and j ending points in the second mileage, each starting point has first position information respectively, each ending point has second position information respectively, the first driving distance of each starting point is the driving distance of this starting point relative to the first starting point, and the second driving distance of each ending point is the driving distance of this ending point relative to the first starting point.

[0061] According to an embodiment of the present invention, among the i starting points, the mileage between adjacent starting points is C1; among the j ending points, the mileage between adjacent ending points is C2;

[0062] where C1 and C2 are natural numbers, C1 > 0, C2 > 0;

[0063] The C2 is the same as or different from the C1.

[0064] In this embodiment, when i = 3, there are 3 starting points. During the driving process of the carrier, the 3 starting points are sequentially recorded as the first starting point, the second starting point, and the third starting point. Then the mileage between the first starting point and the second starting point is C1, and the mileage between the second starting point and the third starting point is C1. Further, the mileage between the first starting point and the third starting point is 2C1. The mileage between adjacent ending points is the same as the above analysis method for starting points. The sum of C2 of all starting points is the first mileage. Specifically, the position where the third starting point is located is the last position reached by the carrier during the driving in the first mileage.

[0065] In some embodiments, C1 is 10 - 50 m, and C2 is 10 - 50 m.

[0066] According to an embodiment of the present invention, according to the carrier driving an additional mileage of C3 relative to the last starting point in the first mileage, the first ending point in the second mileage is obtained;

[0067] Among the mileage that the carrier drives relative to the first ending point, the other ending points among the j ending points are obtained;

[0068] where C3 is a natural number, C3 > C1, and C3 > C2.

[0069] In this embodiment, when there are 3 starting points and 5 ending points, the mileage between the third starting point and the first ending point is C3, that is, the position reached by the carrier after driving an additional mileage of C3 with the third starting point as the starting point is the first ending point. The carrier reaches the position of the second starting point after driving an additional mileage of C2 based on the first ending point, and so on to obtain the remaining ending points among the j ending points. The sum of C3 and C2 of all ending points is the second mileage.

[0070] According to an embodiment of the present invention, the GNSS output position includes a first longitude, a first latitude, and a first altitude; the dead reckoning position includes a second longitude, a second latitude, and a second altitude.

[0071] In this embodiment, by using the GNSS output position and the dead reckoning position which only require longitude, latitude, and altitude information, while improving the accuracy of the odometer parameter calibration result, the difficulty of obtaining information sources is also reduced.

[0072] Specifically, the first GNSS output position is:

[0073] ;

[0074] where P WQi is the first GNSS output position, λ WQ , L WQ , h WQ respectively represent the longitude, latitude, and altitude of the GNSS (satellite receiver) at the starting point of the output at time T, then λ WQi , L WQi , h WQi respectively represent the longitude, latitude, and altitude of the GNSS at the i-th starting point of the output at time T, specifically (i = 1, 2, 3).

[0075] Among them, ;

[0076] The calculation method of the first GNSS output position is as follows:

[0077] ;

[0078] where , , respectively represent the longitude, latitude, and altitude outputs of the GNSS at time t, Qi is the i-th starting point, that is , , respectively represent the longitude, latitude, and altitude of the GNSS output at the i-th starting point. Specifically (i = 1, 2, 3).

[0079] The first dead reckoning position is:

[0080] ;

[0081] where P DQi is the first dead reckoning position, λ DQ , L DQ , h DQ respectively represent the dead reckoning of the longitude, latitude, and altitude of the starting point at time T, then λ DQi , L DQi , hDQi Respectively represent the dead reckoning of the longitude, latitude and altitude of the i-th starting point at time T, specifically (i = 1, 2, 3).

[0082] The first travel distance is: ;

[0083] In the formula, △S Qi is the travel distance of the i-th starting point, specifically (i = 1, 2, 3).

[0084] The second satellite navigation output position is:

[0085] ;

[0086] In the formula, P WZj is the second satellite navigation output position, λ WZ , L WZ , h WZ respectively represent the longitude, latitude and altitude of the end point output by the satellite navigation (satellite receiver) at time T, then λ WZj , L WZj , h WZj respectively represent the longitude, latitude and altitude of the j-th end point output by the satellite navigation at time T, specifically (j = 1, 2, 3, 4, 5).

[0087] Among them, the calculation method of the second satellite navigation output position is the same as that of the first satellite navigation output position;

[0088] The calculation method of the second satellite navigation output position is as follows:

[0089] .

[0090] In the formula, , , respectively represent the longitude, latitude and altitude outputs of the satellite navigation (satellite receiver) at time t, Zj is the j-th end point, that is, , , respectively represent the longitude, latitude and altitude of the j-th end point output by the satellite navigation. Specifically (j = 1, 2, 3, 4, 5).

[0091] The second dead reckoning position is:

[0092] ;

[0093] In the formula, P DZj is the second dead reckoning position, λ DZ , L DZ , h DZAre respectively expressed as dead reckoning of the longitude, latitude, and altitude of the end point at time T, then λ DZj , L DZj , h DZj Are respectively expressed as dead reckoning of the longitude, latitude, and altitude of the j-th end point at time T, specifically (j = 1, 2, 3, 4, 5).

[0094] The second travel distance is: ;

[0095] In the formula, △S Zj Is the travel distance of the j-th end point, specifically (j = 1, 2, 3, 4, 5).

[0096] According to an embodiment of the present invention, based on the first satellite navigation output position, the first dead reckoning position, the first travel distance of the starting point relative to the first starting point among the starting points, the second satellite navigation output position, the second dead reckoning position, and the second travel distance of the end point relative to the first starting point among the starting points, obtain the true displacement vector, dead reckoning displacement vector, travel mileage, and elevation error of the end point;

[0097] Obtain the first odometer parameter based on the true displacement vector, dead reckoning displacement vector, travel mileage, and the elevation error;

[0098] The first odometer parameter includes scale factor error, heading installation offset angle error, and pitch installation offset angle error.

[0099] In this embodiment, the online calculation of the first odometer parameter of the carrier at the end point is realized through the following formula;

[0100] The calculation method of the true displacement vector of the carrier at the end point is as follows:

[0101] ;

[0102] The calculation method of the dead reckoning displacement vector of the carrier at the end point is as follows:

[0103] ;

[0104] The calculation method of the travel mileage of the carrier at the end point is as follows:

[0105] ;

[0106] The calculation method of the elevation error of the carrier at the end point is as follows:

[0107] ;

[0108] In the formula, Is the altitude of dead reckoning the j-th end point, is the height of the j-th end point output by the navigation guidance.

[0109] The calculation method of the scale factor error of the first odometer is as follows:

[0110] ;

[0111] The calculation method of the heading installation declination error of the first odometer is as follows:

[0112] ;

[0113] In the formula, Z is the third component after the cross product of the vector and the vector

[0114] The calculation method of the pitch installation declination error of the first odometer is as follows:

[0115] .

[0116] In the above formulas (i = 1, 2, 3; j = 1, 2, 3, 4, 5).

[0117] Through the above formulas, three groups of calibration results (parameters of the first odometer) at the end point can be calculated , which are the scale factor error, the heading installation declination error, and the pitch installation declination error in sequence.

[0118] The cumulative averaging process of the second odometer parameters includes:

[0119] Adding the calibration results and the counting results of the estimated scale factor to obtain the target scale factor in the target odometer parameters;

[0120] Adding the calibration results and the counting results of the estimated heading installation declination to obtain the target heading installation declination in the target odometer parameters;

[0121] Adding the calibration results and the counting results of the estimated pitch installation declination to obtain the target pitch installation declination in the target odometer parameters.

[0122] According to an embodiment of the present invention, the preset odometer parameters include a preset scale factor, a preset heading installation declination, and a preset pitch installation declination;

[0123] Obtain the second odometer parameters according to the scale factor error, the heading installation declination error, the pitch installation declination error, the preset scale factor, the preset heading installation declination, and the preset pitch installation declination;

[0124] The second odometer parameter includes a deduced scale factor, a deduced heading installation declination, and a deduced pitch installation declination.

[0125] In this embodiment, the calculation formulas for the scale factor, the heading installation declination, and the pitch installation declination are as follows:

[0126] ;

[0127] In the formula, , , respectively represent the scale factor, the heading installation declination, and the pitch installation declination of the preset odometer parameter; , , respectively represent the latest calibration results of the scale factor, the heading installation declination, and the pitch installation declination of the j-th end point relative to the i-th start point.

[0128] According to an embodiment of the present invention, that the change amount between the second odometer parameter and the preset odometer parameter is less than a preset range includes:

[0129] The change amount between the deduced scale factor in the second odometer parameter and the preset scale factor in the preset odometer parameter is less than the preset range.

[0130] In this embodiment, since the changes in the heading installation declination and the pitch installation declination in the odometer parameter are relatively small, and the change in the odometer scale factor is obvious, the second odometer scale factor parameter calculated is compared with the preset scale factor of the preset odometer parameter by using the following formula:

[0131] ;

[0132] In the formula, ρ is the preset range, and the value range of ρ is 0.003 to 0.005.

[0133] If the change amount between the scale factor in the second odometer parameter and the preset scale factor in the preset odometer parameter is less than the preset range ρ, it is considered that the calibration result of the second odometer parameter is credible. Thus, automatic screening of the calibration result is achieved.

[0134] According to an embodiment of the present invention, after the change amount between the second odometer parameter and the preset odometer parameter is within the preset range, when there are i start points and i > 1, where i is a natural number, the second odometer parameters respectively possessed by the carrier when located at the end point relative to the i start points are obtained, and the i second odometer parameters are subjected to cumulative averaging processing to obtain the target odometer parameter.

[0135] In this embodiment, by obtaining the second odometer parameters that the carrier has with respect to i starting points when it is at the end point, the accuracy of the odometer parameter calibration result is further improved.

[0136] According to an embodiment of the present invention, when there are i starting points, j end points, and i>1 and j>1, where i and j are natural numbers, the second odometer parameters that the carrier has with respect to i starting points when it is at j end points are respectively obtained, and the i second odometer parameters that j end points respectively have are subjected to cumulative averaging processing to obtain target odometer parameters.

[0137] In this embodiment, specifically, one end point has i second odometer parameters, and for j end points, the i second odometer parameters of each end point are respectively obtained. By respectively obtaining the second odometer parameters that the carrier has with respect to i starting points when it is at j end points, the accuracy of the odometer parameter calibration result is further improved.

[0138] According to an embodiment of the present invention, the cumulative averaging processing of the second odometer parameters includes:

[0139] Accumulating the calibration results of the deduced scale factor to obtain the target scale factor in the target odometer parameters;

[0140] Accumulating the calibration results of the deduced heading installation offset angle to obtain the target heading installation offset angle in the target odometer parameters;

[0141] Accumulating the calibration results of the deduced pitch installation offset angle to obtain the target pitch installation offset angle in the target odometer parameters.

[0142] In this embodiment, by accumulating the calibration results of the second odometer parameters, the final target odometer parameter calibration result is determined by the following formula:

[0143] ;

[0144] In the formula, are respectively the target scale factor, the target heading installation offset angle, and the target pitch installation offset angle of the target odometer parameters, (i = 1, 2, 3; j = 1, 2, 3, 4, 5).

[0145] After that, the preset odometer parameters are updated to the target odometer parameters, thereby realizing online calibration and automatic update and storage of the odometer parameters for the positioning and orientation system to perform alignment and navigation.

[0146] According to an embodiment of the present invention, a storage medium stores a computer program thereon, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0147] The following explanations are given in this article:

[0148] 1. Principle of odometer dead reckoning:

[0149] The odometer measures the rotation of the wheel to output the sampling period and the mileage increment of the vehicle during this period , where is the number of pulses output by the odometer per cycle, and is the scale factor of the odometer. Define the vehicle body coordinate system m. The mileage increment in the m system output by the odometer per cycle is:

[0150] ;

[0151] In the formula, represents the transpose of the matrix .

[0152] There is an installation relationship between the inertial navigation and the odometer, and there are pitch installation angles , roll installation angles and azimuth installation angles between the m system and the j system. Define that when the m system looks up relative to the j system is positive, when it tilts to the right is positive, and when it turns to the right is positive. At this time, the transformation matrix from the j system to the m system can be expressed as:

[0153] ;

[0154] In the formula, the symbol represents , represents .

[0155] The mileage increment output by the odometer in the j system is:

[0156] ;

[0157] In the formula, represents the component of the mileage increment in the j system.

[0158] Furthermore, the mileage increment in the n system can be obtained:

[0159] ;

[0160] In the formula, represents the component of the mileage increment in the n system, including the eastward component , the northward component and the upward component ; Denote the transformation matrix from the j - system to the n - system at time t - 1.

[0161] The position update algorithm for dead reckoning can be obtained:

[0162] ;

[0163] ;

[0164] ;

[0165] In the formula, , respectively represent the longitudes at time t - 1 and time t; , respectively represent the latitudes at time t - 1 and time t; , respectively represent the altitudes at time t - 1 and time t; and respectively represent the radius of the earth's meridian and the radius of the prime vertical.

[0166] 2. Analysis of dead reckoning error:

[0167] Ignoring small - quantity errors, the position increment error for each cycle of dead reckoning can be obtained:

[0168] ;

[0169] In the formula, , can be considered to be basically unchanged, and can also be approximated as a constant value within a certain period of time. Integrating it gives the position error model:

[0170] ;

[0171] In the formula, is the position error generated during the driving process; is the total displacement of the vehicle during driving, is the total mileage of the vehicle during driving.

[0172] In the formula, the displacement represents the displacement vector between the starting and ending positions, while the mileage represents the path length traveled.

[0173] Projecting the above formula onto the horizontal direction, we can obtain:

[0174] ;

[0175] In the formula, is 's horizontal component, that is, ; is the horizontal component of, i.e., .

[0176] Projecting the above formula in the height direction, we can obtain:

[0177] ;

[0178] In the formula, is the elevation error at the starting and ending positions of the vehicle carrier. When the vehicle carrier is driving normally, is very small, so the height error generated is very small.

[0179] Embodiment 1

[0180] The online calibration path of the odometer parameters is as Figure 2 shown. The calibration scheme of this embodiment includes 3 starting points and 5 ending points. Figure 2 Among them, the range of L Q12 , L Q23 , L Z12 , L Z23 , L Z34 , L Z45 is 10m to 50m; the range of L QZ is 5km to 10km; the 3 starting points and 5 ending points are selected at open and unobstructed positions. By obtaining the reference positions, dead reckoning positions, and driving distances of these 8 points, and using the corresponding calculation methods and data selection schemes, the online calibration results of the odometer parameters are obtained.

[0181] 1. The specific implementation scheme of the online calibration of the odometer parameters is as follows:

[0182] 1.1 The positioning and orientation system is powered on and initialized at starting point 1, and initial alignment begins;

[0183] 1.2 At starting point 1, record the average position output QZ of the satellite receiver (GNSS) within T seconds, and use this position as the dead reckoning starting position , and record the distance from starting point 1 relative to starting point 1; among them, the calculation method is as follows:

[0184] ;

[0185] In the formula, , , respectively represent the longitude, latitude, and altitude outputs of the satellite receiver at time t.

[0186] 1.3 After completing the initial alignment at starting point 1, the vehicle travels a distance L Q12 and reaches starting point 2, where the average value of the position output of satellite receiver T QZ within seconds is recorded (calculation method is the same as ), the dead reckoning position and the distance of starting point 2 relative to starting point 1 ;

[0187] 1.4 The vehicle travels a distance L Q23 and reaches starting point 3, where the average value of the position output of satellite receiver T QZ within seconds is recorded (calculation method is the same as ), the dead reckoning position and the distance of starting point 3 relative to starting point 1 ;

[0188] 1.5 The vehicle travels a distance L QZ and reaches end point 1, where the average value of the position output of satellite receiver T QZ within seconds is recorded (calculation method is the same as ), the dead reckoning position and the distance of end point 1 relative to starting point 1 ;

[0189] 1.6 At end point 1, using the parameters at end point 1 ( , , ), the parameters at starting point 1 ( , , ), the parameters at starting point 2 ( , , ), and the parameters at starting point 3 ( , , ). The online calculation of the first odometer parameters of the carrier at end point 1 is realized through the following formula:

[0190] True displacement vector:

[0191] ;

[0192] Dead reckoning displacement vector:

[0193] ;

[0194] Traveled mileage:

[0195] ;

[0196] Elevation error:

[0197] ;

[0198] Wherein, is the height of the j-th end point of dead reckoning, is the height of the j-th end point output by satellite navigation.

[0199] Scale factor error of the first odometer:

[0200] ;

[0201] Heading installation declination error of the first odometer:

[0202] ;

[0203] Pitch installation declination error of the first odometer:

[0204] ;

[0205] In the above formula, , . Through the above formula, three groups of calibration results at end point 1 can be calculated . When i = 1, it is the first group of calibration results at end point 1; when i = 2, it is the second group of calibration results at end point 1; when i = 3, it is the third group of calibration results at end point 1, which are the scale factor error, heading installation declination error and pitch installation declination error of end point 1 in sequence.

[0206] 1.7 The vehicle travels a distance L Z12 and reaches end point 2. Record the mean value of the position output of the satellite receiver T QZ within seconds (the calculation method is the same as ), the dead reckoning position and the distance of end point 2 relative to start point 1;

[0207] Similar to step 1.6, three groups of calibration results at end point 2 can be calculated .

[0208] 1.8 The vehicle travels a distance L Z23 and reaches end point 3. Record the mean value of the position output of the satellite receiver T QZ within seconds (the calculation method is the same as ), the dead reckoning position and the distance of end point 3 relative to start point 1;

[0209] Similar to step 1.6, three groups of calibration results at endpoint 3 can be calculated. .

[0210] 1.9 The vehicle travels a distance L Z34 and reaches endpoint 4, where the mean value of the position output of satellite receiver T QZ within T seconds is recorded (the calculation method is the same as ), the dead reckoning position and the distance of endpoint 4 relative to starting point 1 ;

[0211] Similar to step 1.6, three groups of calibration results at endpoint 4 can be calculated. .

[0212] 1.10 The vehicle travels a distance L Z45 and reaches endpoint 5, where the mean value of the position output of satellite receiver T QZ within T seconds is recorded (the calculation method is the same as ), the dead reckoning position and the distance of endpoint 5 relative to starting point 1 ;

[0213] Similar to step 1.6, three groups of calibration results at endpoint 5 can be calculated. .

[0214] Among them, T QZ is 30, that is, the mean value of the position output of satellite receiver within 30 seconds at this location is recorded.

[0215] In this article, starting points 1 / 2 / 3 are equivalent to the first / second / third starting points, and endpoints 1 / 2 / 3 / 4 / 5 are equivalent to the first / second / third / fourth / fifth endpoints, which are just different expressions to represent the same concept.

[0216] 1.11 After obtaining 15 groups of calibration results of the above 5 endpoints, data screening can be carried out.

[0217] 2. On-line calibration data processing of odometer parameters

[0218] 2.1 Parameter calculation

[0219] After obtaining the endpoint calibration results of 15 groups at the above 3 starting points, the estimated scale factor, estimated heading installation offset angle, and estimated pitch installation offset angle of the second odometer parameter are calculated through the following formula:

[0220] ;

[0221] In the formula, , , respectively represent the preset scale factor, preset heading installation offset angle, and preset pitch installation offset angle of the original storage (preset odometer parameters); and and successively represent the latest calibration results of the deduced scale factor, deduced heading installation offset angle, and deduced pitch installation offset angle of the j-th end point relative to the i-th start point.

[0222] 2.2 Parameter Screening and Calibration Result Determination

[0223] In an actual positioning and orientation system, since the changes in the heading installation offset angle and pitch installation offset angle are relatively small, while the change in the odometer scale factor is obvious, so the 15 groups calculated and the preset scale factor of the original stored value are compared using the following formula:

[0224] ;

[0225] In the formula, ρ is the preset range, and the value range of ρ can be 0.003 - 0.005.

[0226] If the change amount between the deduced scale factor and the preset scale factor is less than or equal to the set threshold (preset range) ρ, then the calibration result of this group of odometer parameters is considered credible; if the change amount between the deduced scale factor and the preset scale factor is greater than the set threshold ρ, then the calibration result of this group is considered not credible.

[0227] Eliminate the calibration result of the group of odometer parameters that is not credible, select the calibration results of the remaining groups of credible odometer parameters for cumulative addition of the calibration results, and obtain the final target odometer parameter calibration result through the following formula:

[0228] ;

[0229] In the formula, successively are the target scale factor, target heading installation offset angle, and target pitch installation offset angle, (i = 1, 2, 3; j = 1, 2, 3, 4, 5).

[0230] Or, re - calibrate the non - credible calibration results until the calibration results are credible, and then perform cumulative addition of the calibration results of all groups to obtain the final target odometer parameter calibration result.

[0231] 2.3 Parameter Storage

[0232] After obtaining the final calibration result through step 2.2, update the original stored value to the target odometer parameters , thus completing the online calibration and automatic update storage of the odometer parameters for the positioning and orientation system to perform alignment and navigation.

[0233] Embodiment 2

[0234] This example provides a storage medium with a computer program stored thereon. When the computer program is executed by a processor, the steps of the method in Embodiment 1 above are implemented.

[0235] Those of ordinary skill in the art can understand that the above embodiments are specific cases for implementing the present disclosure, and in actual applications, various changes can be made to them in form and details without departing from the scope of the present disclosure.

Claims

1. An online calibration method for odometer parameters, characterized in that Including the following steps: Taking the position of the vehicle during the first mileage as the starting point, the vehicle has i starting points during the first mileage, where i is a natural number, i ≥1, taking the position of the vehicle during the second mileage as the ending point, the vehicle has j ending points during the second mileage, where j is a natural number, j ≥ i， The second mileage is the mileage that the vehicle travels after traveling the first mileage; Obtain the first position information of the carrier at the starting point, where the first position information includes the first satellite navigation output position of the starting point, the first dead reckoning position, and the first travel distance of the starting point relative to the first starting point among the starting points; Obtain the second position information of the carrier at the ending point, where the second position information includes the second satellite navigation output position of the ending point, the second dead reckoning position, and the second travel distance of the ending point relative to the first starting point among the starting points; Obtain the true displacement vector, dead reckoning displacement vector, travel mileage, and elevation error of the ending point according to the first position information and the second position information; Obtain the first odometer parameters of the carrier according to the true displacement vector, dead reckoning displacement vector, travel mileage, and the elevation error, where the first odometer parameters include scale factor error, heading installation offset angle error, and pitch installation offset angle error; Obtain the second odometer parameters of the carrier according to the preset odometer parameters of the carrier and the first odometer parameters, where the preset odometer parameters include a preset scale factor, a preset heading installation offset angle, and a preset pitch installation offset angle, and the second odometer parameters include a calculated scale factor, a calculated heading installation offset angle, and a calculated pitch installation offset angle; Obtain the target odometer parameters of the carrier according to the change amount between the second odometer parameters and the preset odometer parameters being within a preset range, where the target odometer parameters include a target scale factor, a target heading installation offset angle, and a target pitch installation offset angle; The change amount between the second odometer parameters and the preset odometer parameters being less than the preset range includes that the change amount between the calculated scale factor and the preset scale factor is less than or equal to a set threshold.

2. The online calibration method for odometer parameters according to claim 1, characterized in that, i The mileage of each of the starting points is inconsistent; j The mileage of each of the said endpoints is inconsistent.

3. An online calibration method for odometer parameters according to claim 2, characterized in that, i Among the starting points, the mileage between adjacent starting points is C1; j Among the ending points, the mileage between adjacent ending points is C2; Where C1 and C2 are natural numbers, C1 > 0, C2 > 0; The C2 is the same as or different from the C1.

4. The online calibration method for odometer parameters according to claim 3, characterized in that, Obtain the first ending point of the second mileage according to the carrier traveling an additional mileage of C3 relative to the last starting point in the first mileage; Obtain other endpoints among the endpoints according to the mileage that the carrier travels again relative to the first endpoint j among the endpoints Where C3 is a natural number, C3 > C1, and C3 > C2.

5. The online calibration method for odometer parameters according to claim 1, characterized in that, The satellite navigation output position includes a first longitude, a first latitude, and a first altitude; the dead reckoning position includes a second longitude, a second latitude, and a second altitude.

6. The online calibration method for odometer parameters according to claim 1, wherein After the variation between the second odometer parameter and the preset odometer parameter is within the preset range, when there are i and i > 1, where i is a natural number, obtain the second odometer parameters of the carrier relative to i starting points when the carrier is at the end point, and perform cumulative averaging on i second odometer parameters to obtain the target odometer parameter.

7. An on-line calibration method for odometer parameters according to claim 1, characterized in that After the change amount between the second odometer parameter and the preset odometer parameter is within the preset range, when there are i at the starting point, and j at the ending point, and i > 1 and j > 1, where i and j are natural numbers, respectively obtain the second odometer parameters that the carrier has when located at j ending points with respect to i starting points, and perform cumulative averaging processing on the j second odometer parameters respectively possessed by i ending points to obtain the target odometer parameter.

8. An online calibration method for odometer parameters according to claim 6 or 7, characterized in that The cumulative averaging process of the second odometer parameters includes: According to the second odometer parameters including a calculated scale factor, a calculated heading installation offset angle, and a calculated pitch installation offset angle; Accumulate the calibration results of the calculated scale factor to obtain the target scale factor in the target odometer parameters; Accumulate the calibration results of the calculated heading installation offset angle to obtain the target heading installation offset angle in the target odometer parameters; Accumulate the calibration results of the calculated pitch installation offset angle to obtain the target pitch installation offset angle in the target odometer parameters.

9. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 - 8.

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