CN113375699A

CN113375699A - Inertial measurement unit installation error angle calibration method and related equipment

Info

Publication number: CN113375699A
Application number: CN202110922600.3A
Authority: CN
Inventors: 费再慧; 朱磊; 贾双成; 李成军
Original assignee: Zhidao Network Technology Beijing Co Ltd
Current assignee: Zhidao Network Technology Beijing Co Ltd
Priority date: 2021-08-12
Filing date: 2021-08-12
Publication date: 2021-09-10

Abstract

The application relates to an inertial measurement unit installation error angle calibration method and related equipment. The method comprises the following steps: when the vehicle is in a specific state, acquiring multiple groups of first measurement data and multiple groups of second measurement data of the inertia measurement unit and multiple groups of positioning data of the satellite positioning module; obtaining a plurality of pitch angle installation errors and a plurality of roll angle installation errors of an inertia measurement unit according to a plurality of groups of acceleration data of a plurality of groups of first measurement data, and respectively determining the pitch angle installation errors and the roll angle installation errors of the inertia measurement unit; and obtaining a plurality of first course angles of the vehicle according to the plurality of groups of second measurement data, obtaining a plurality of second course angles of the vehicle according to the plurality of groups of positioning data, obtaining a plurality of course angle installation errors of the inertial measurement unit, and determining the course angle installation errors of the inertial measurement unit. The scheme provided by the application can conveniently calibrate the installation error angle of the inertia measurement unit, and improve the calibration efficiency of the installation error angle of the inertia measurement unit.

Description

Inertial measurement unit installation error angle calibration method and related equipment

Technical Field

The application relates to the technical field of navigation, in particular to a method for calibrating an installation error angle of an inertial measurement unit and related equipment.

Background

An Inertial navigation system including an Inertial Measurement Unit (IMU) can update navigation information including attitude, speed, and position by using Measurement data of the Inertial Measurement Unit without external force. The IMU contains three uniaxial accelerometers and three uniaxial gyroscopes for measuring angular velocity and acceleration of an object in inertial space. The inertial navigation system derives navigation information at the moment from navigation information at the previous moment according to the acceleration and the angular velocity of the IMU. The inertial navigation system can be applied to all complex environments because the inertial navigation system does not use external force for navigation.

However, in the installation process of the IMU, because the inertial navigation coordinate system of the IMU cannot be guaranteed to be completely consistent with the carrier coordinate system, certain errors exist in the installation of the IMU, and if the installation errors of the IMU are not calibrated, the navigation information of the inertial navigation system has very large errors, so that it is essential to calibrate the installation error angle of the IMU.

The IMU installation error angle calibration in the related technology is carried out by means of special calibration equipment and a leveling marble platform, the special calibration equipment and the leveling marble platform are expensive, a large amount of manual operation is needed in the calibration process, the calibration efficiency is low, and a user cannot calibrate the IMU installation error angle conveniently.

Disclosure of Invention

In order to solve or partially solve the problems in the related art, the application provides an installation error angle calibration method of an inertial measurement unit and related equipment, which can conveniently calibrate the installation error angle of the inertial measurement unit and improve the efficiency of the installation error angle calibration of the inertial measurement unit.

The application provides a method for calibrating an installation error angle of an inertial measurement unit in a first aspect, and the method comprises the following steps:

when a vehicle is in a first state, acquiring multiple groups of first measurement data of an inertia measurement unit, and when the vehicle is in a second state, acquiring multiple groups of second measurement data of the inertia measurement unit and multiple groups of positioning data of a satellite positioning module;

obtaining a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertia measurement unit according to a plurality of groups of acceleration data of the plurality of groups of first measurement data;

respectively determining the pitch angle installation error and the roll angle installation error of the inertia measurement unit according to the plurality of pitch angle installation errors and the plurality of roll angle installation errors;

obtaining a plurality of first course angles of the vehicle according to the plurality of groups of second measurement data, and obtaining a plurality of second course angles of the vehicle according to the plurality of groups of positioning data;

obtaining a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles;

and determining the course angle installation error of the inertial measurement unit according to the plurality of course angle installation errors.

Preferably, the determining the pitch angle installation error and the roll angle installation error of the inertial measurement unit according to the pitch angle installation errors and the roll angle installation errors respectively includes:

and if the installation errors of the plurality of pitch angles and the installation errors of the plurality of roll angles are stable, determining that the average value of the installation errors of the plurality of pitch angles is the installation error of the pitch angle of the inertia measurement unit, and determining that the average value of the installation errors of the plurality of roll angles is the installation error of the roll angle.

Preferably, the determining the course angle installation error of the inertial measurement unit according to the plurality of course angle installation errors includes:

and if the plurality of course angle installation errors are stable, determining the average value of the plurality of course angle installation errors as the course angle installation error of the inertial measurement unit.

Preferably, the method further comprises:

and configuring the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertia measurement unit to an automatic driving system.

The second aspect of the present application provides another method for calibrating an installation error angle of an inertial measurement unit, where the method is applied to a server, and the method includes:

when a vehicle is in a first state, a vehicle-mounted intelligent device acquires and uploads multiple groups of first measurement data of an inertia measurement unit, and when the vehicle is in a second state, the vehicle-mounted intelligent device acquires and uploads multiple groups of second measurement data of the inertia measurement unit and multiple groups of positioning data of a satellite positioning module;

determining course angle installation errors of the inertial measurement unit according to the plurality of course angle installation errors;

and sending the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertia measurement unit to the vehicle-mounted intelligent equipment.

The third aspect of the present application provides an inertial measurement unit installation error angle calibration apparatus, including:

the system comprises an original data acquisition module, a satellite positioning module and a data processing module, wherein the original data acquisition module is used for acquiring multiple groups of first measurement data of an inertia measurement unit when a vehicle is in a first state, and acquiring multiple groups of second measurement data of the inertia measurement unit and multiple groups of positioning data of the satellite positioning module when the vehicle is in a second state;

the first error module is used for obtaining a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertial measurement unit according to a plurality of groups of acceleration data of the plurality of groups of first measurement data obtained by the original data obtaining module;

an error determining module, configured to determine pitch angle installation errors and roll angle installation errors of the inertial measurement unit according to the multiple pitch angle installation errors and the multiple roll angle installation errors obtained by the first error module;

the course angle acquisition module is used for acquiring a plurality of first course angles of the vehicle according to the plurality of groups of second measurement data acquired by the original data acquisition module and acquiring a plurality of second course angles of the vehicle according to the plurality of groups of positioning data acquired by the original data acquisition module;

the second error module is used for obtaining a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles obtained by the course angle obtaining module;

the error determining module is further configured to determine the course angle installation error of the inertial measurement unit according to the plurality of course angle installation errors obtained by the second error module.

Preferably, the apparatus further comprises:

and the configuration module is used for configuring the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertial measurement unit determined by the error determination module to an automatic driving system.

A fourth aspect of the present application provides a server, comprising:

the receiving unit is used for receiving multiple groups of first measurement data of the inertial measurement unit, which are acquired and uploaded by the vehicle-mounted intelligent equipment when the vehicle is in a first state, and receiving multiple groups of second measurement data of the inertial measurement unit and multiple groups of positioning data of the satellite positioning module, which are acquired and uploaded by the vehicle-mounted intelligent equipment when the vehicle is in a second state;

the first error unit is used for obtaining a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertial measurement unit according to a plurality of groups of acceleration data of the plurality of groups of first measurement data received by the receiving unit;

an error determination unit, configured to determine pitch angle installation errors and roll angle installation errors of the inertial measurement unit according to the multiple pitch angle installation errors and the multiple roll angle installation errors obtained by the first error unit, respectively;

the course angle acquisition unit is used for acquiring a plurality of first course angles of the vehicle according to the plurality of groups of second measurement data received by the receiving unit and acquiring a plurality of second course angles of the vehicle according to the plurality of groups of positioning data received by the receiving unit;

the second error unit is used for obtaining a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles obtained by the course angle obtaining unit;

the error determining unit is further configured to determine course angle installation errors of the inertial measurement unit according to the plurality of course angle installation errors obtained by the second error unit;

and the sending unit is used for sending the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertia measurement unit determined by the error determination unit to the vehicle-mounted intelligent equipment.

The fifth aspect of the application provides a system for calibrating an installation error angle of an inertial measurement unit, wherein the system comprises the vehicle-mounted intelligent device and a server;

the vehicle-mounted intelligent device is used for acquiring multiple groups of first measurement data of an inertia measurement unit when a vehicle is in a first state, acquiring multiple groups of second measurement data of the inertia measurement unit and multiple groups of positioning data of a satellite positioning module when the vehicle is in a second state, uploading the multiple groups of first measurement data, the multiple groups of second measurement data and the multiple groups of positioning data to the server, and receiving a pitch angle installation error, a roll angle installation error and a course angle installation error of the inertia measurement unit, which are sent by the server;

the server is used for receiving the multiple groups of first measurement data, the multiple groups of second measurement data and the multiple groups of positioning data uploaded by the vehicle-mounted intelligent equipment, obtaining multiple pitch angle installation errors and multiple roll angle installation errors of the inertial measurement unit according to the multiple groups of acceleration data of the multiple groups of first measurement data, respectively determining the pitch angle installation errors and the roll angle installation errors of the inertial measurement unit according to the multiple pitch angle installation errors and the multiple roll angle installation errors, obtaining multiple first course angles of the vehicle according to the multiple groups of second measurement data, obtaining multiple second course angles of the vehicle according to the multiple groups of positioning data, obtaining multiple course angle installation errors of the inertial measurement unit according to the multiple first course angles and the multiple second course angles, and obtaining multiple course angle installation errors of the inertial measurement unit according to the multiple course angle installation errors, and determining a course angle installation error of the inertial measurement unit, and sending the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertial measurement unit to the vehicle-mounted intelligent device.

A sixth aspect of the present application provides an electronic device, comprising:

a processor; and

a memory having executable code stored thereon, which when executed by the processor, causes the processor to perform the method as described above.

A seventh aspect of the application provides a non-transitory machine-readable storage medium having stored thereon executable code, which when executed by a processor of an electronic device, causes the processor to perform the method as described above.

The technical scheme provided by the application can comprise the following beneficial effects:

according to the technical scheme, the calibration of the installation error angle of the inertial measurement unit can be carried out by utilizing the measurement data of the inertial measurement unit and the positioning data of the satellite positioning module when the vehicle is in different motion states, specific calibration equipment is not needed, the operation is simple and convenient, the installation error angle of the inertial measurement unit can be conveniently calibrated, the efficiency of the calibration of the installation error angle of the inertial measurement unit is improved, the inertial measurement unit can provide measurement data with higher precision, the positioning and navigation precision of the inertial measurement unit is improved, and the positioning and navigation errors caused by the installation error of the inertial measurement unit are reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application, as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.

FIG. 1 is a schematic flow chart illustrating a method for calibrating an installation error angle of an inertial measurement unit according to an embodiment of the present application;

FIG. 2 is another schematic flow chart of a method for calibrating an installation error angle of an inertial measurement unit according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of an installation error angle calibration device of an inertial measurement unit according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a server according to an embodiment of the present application;

FIG. 5 is a schematic structural diagram of an installation error angle calibration system of an inertial measurement unit according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of an electronic device shown in an embodiment of the present application.

Detailed Description

Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While embodiments of the present application are illustrated in the accompanying drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

The embodiment of the application provides a method for calibrating an installation error angle of an inertia measurement unit, which can conveniently calibrate the installation error angle of the inertia measurement unit and improve the efficiency of calibrating the installation error angle of the inertia measurement unit.

The coordinate system employed in the practice of this application is defined as follows:

and (b) a carrier coordinate system. The origin O of the carrier coordinate system is in the center of mass of the carrier, and the OX axis and the OY axis are in the horizontal plane of the ground, the OX axis points to the right side of the carrier, the OY axis points forwards along the longitudinal axis direction of the carrier, and the OZ is vertical to the carrier and upwards. The carrier coordinate system forms a right-hand rectangular coordinate system, when the carrier is not pitching or inclined, OX and OY are horizontal planes, and the OZ axis points to the zenith along a vertical line. The determined state of the carrier coordinate system with respect to the geographical coordinate system may be represented by an attitude angle.

Geographic coordinate system (n system). The geographical coordinate system takes the gravity center of the carrier or a certain point on the earth surface as an origin O, the OX axis points east in the horizontal plane of the earth, the OY axis and the local meridian line point to true north, and the OZ axis points upward along the vertical line of the earth to form a right-hand coordinate system. Common geographic coordinate systems are: the east-north-sky coordinate system. The geographic coordinate system may also be referred to as a geographic navigation system.

The inertial frame (i-frame) is a reference frame which is stationary relative to the inertial space or moves linearly at a constant speed, and the reference frame determined relative to the stars is called the inertial space. For example, in the earth center inertial coordinate system, the origin O of the earth center inertial coordinate system is located at the earth center, the Z axis is consistent with the earth rotation axis, and the X, Y axis is located in the equatorial plane to form a right-hand rectangular coordinate system. The earth center inertial coordinate system does not participate in the rotation motion of the earth, namely the three coordinate axes of the earth center inertial coordinate system are kept unchanged in the direction of the inertial space.

And in the inertial navigation coordinate system (p system), the axis is the gravity center of the inertial measurement unit, the x axis refers to the right side of the carrier, the y axis refers to the front side of the carrier, the y axis is vertical to the x axis, the z axis refers to the upper side of the carrier, and the z axis, the x axis and the y axis form a rectangular coordinate system meeting the right-hand rule.

The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

The first embodiment is as follows:

fig. 1 is a schematic flow chart of an installation error angle calibration method for an inertial measurement unit according to an embodiment of the present application.

Referring to fig. 1, a method for calibrating an installation error angle of an inertial measurement unit includes:

in step S101, a plurality of sets of first measurement data of the inertial measurement unit are acquired while the vehicle is in the first state.

In one embodiment, the autonomous vehicle is equipped with an inertial navigation system that includes an inertial measurement unit that may employ MPU-6050 (6-axis motion processing assembly), the MPU-6050 including a three-axis accelerometer and a three-axis gyroscope. The coordinate axis displayed on the MPU-6050 chip is the coordinate axis of the gyroscope, and the positive direction of the coordinate axis of the accelerometer in the MPU-6050 chip is opposite to the positive direction of the coordinate axis of the gyroscope. When the MPU-6050 is installed, the X axis marked on the chip points to the front of the vehicle, the Y axis points to the left side of the vehicle, the Z axis points to the upper side of the vehicle, namely the X axis of the accelerometer points to the rear of the vehicle, the Y axis points to the right side of the vehicle, and the Z axis points to the lower side of the vehicle, so that when the vehicle accelerates forwards, acceleration data measured by the accelerometer is positive.

In a specific implementation mode, when a vehicle is in a horizontal uniform speed state, K groups of acceleration data on three axes of K groups of three-axis accelerometers are acquired according to a set time, wherein K is an integer greater than 1, and the kth time isAcceleration data

。

It should be noted that the horizontal uniform speed state of the vehicle may be that the vehicle is in a horizontal stationary state, or that the vehicle is in a horizontal uniform speed motion state.

In step S102, a plurality of pitch angle mounting errors and a plurality of roll angle mounting errors of the inertial measurement unit are obtained from the plurality of sets of acceleration data.

In one embodiment, let pitch angle be θ, roll angle be φ, and heading angle be Ψ. When the vehicle is in a horizontal uniform velocity state, namely the inertial measurement unit is in a horizontal uniform velocity state, a rotation matrix from an inertial navigation coordinate system (system p) to a carrier coordinate system (system b) is as follows:

in one embodiment, the inertial measurement unit is only influenced by gravity when the vehicle is in a horizontal uniform speed state, and the acceleration data of the three axes of the three-axis accelerometer

In the formula (I), wherein,

and g is the earth gravity acceleration value.

Acceleration data according to actual output of MPU-6050 triaxial accelerometer at k time

The pitch angle mounting error theta of the inertial measurement unit at the k-th time can be calculated_kTransverse roll angle installation error phi_k。

Obtaining a kth pitch angle installation error according to the acceleration data at the kth moment:

obtaining a kth roll angle installation error according to the acceleration data at the kth moment:

in one embodiment, K pitch angle installation errors and K roll angle installation errors are calculated from K sets of acceleration data of K sets of first measurement data of the inertial measurement unit.

In step S103, it is determined whether or not the plurality of pitch angle installation errors and the plurality of roll angle installation errors are stable; if yes, go to step S104; if not, step S101 is performed.

In a specific embodiment, whether the K pitch angle installation errors and the K roll angle installation errors are stable or not can be judged by a sliding average method; if the K pitch angle installation errors and the K roll angle installation errors are stable, executing step S104; if the K pitch angle installation errors and the K roll angle installation errors are unstable, step S101 is performed.

In step S104, a pitch angle mounting error and a roll angle mounting error of the inertial measurement unit are determined based on the plurality of pitch angle mounting errors and the plurality of roll angle mounting errors, respectively.

In one embodiment, if the K pitch angle installation errors and the K roll angle installation errors are stable, an average of the K pitch angle installation errors and an average of the K roll angle installation errors may be calculated, respectively, the average of the K pitch angle installation errors is determined as the pitch angle installation error of the inertial measurement unit, and the average of the K roll angle installation errors is determined as the roll angle installation error of the inertial measurement unit.

In step S105, when the vehicle is in the second state, a plurality of sets of second measurement data of the inertial measurement unit and a plurality of sets of positioning data of the satellite positioning module are acquired.

In one embodiment, the autonomous vehicle is further equipped with a satellite Positioning module, which may include, but is not limited to, at least one of a GPS (Global Positioning System) satellite module, a beidou satellite Positioning module, and an RTK (real time kinematic) satellite Positioning module.

In one embodiment, the vehicle runs on a straight road, keeps running in a certain fixed direction, is in a horizontal running state, and can obtain M groups of positioning data of the RTK satellite positioning module, M groups of three-axis acceleration and three-axis angular velocity of the inertial measurement unit according to time.

In one embodiment, in the M sets of positioning data of the RTK satellite positioning module, a straight-line distance between the positioning data at the M-1 th time and the positioning data at the M-th time may be greater than 3 meters.

It should be noted that the M sets of positioning data of the RTK satellite positioning module and the M sets of three-axis accelerations and three-axis angular velocities of the inertial measurement unit are aligned in time and space.

In step S106, a plurality of first heading angles of the vehicle are obtained according to the plurality of sets of second measurement data of the inertial measurement unit.

In one embodiment, the inertial navigation system may update the attitude matrix of the inertial navigation system at the m-th moment according to the three-axis acceleration and the three-axis angular velocity at the m-th moment, the attitude matrix at the m-1 th moment, and the rotation matrix among the carrier coordinate system, the geographic coordinate system, the inertial coordinate system, and the inertial navigation coordinate system. Obtaining a first heading angle psi of the vehicle at the m moment according to the attitude matrix of the inertial navigation system at the m moment_I,m. M first heading angles of the vehicle can be obtained according to the M groups of three-axis acceleration and three-axis angular velocity.

In step S107, a plurality of second heading angles of the vehicle are obtained according to the plurality of sets of positioning data.

In one embodiment, the RTK satellite positioning module may obtain the second heading angle Ψ at the mth time of the vehicle according to the positioning data at the mth time_W,m. M second heading angles of the vehicle can be obtained according to the M groups of positioning data.

In step S108, a plurality of course angle installation errors of the inertial measurement unit are obtained according to the plurality of first course angles and the plurality of second course angles of the vehicle.

In one embodiment, the first heading angle Ψ for the m-th time of the vehicle_I,mSecond heading angle psi from m-th moment_W,mAnd performing difference making to obtain the course angle installation error at the mth moment. And obtaining M course angle installation errors according to M first course angles and M second course angles of the vehicle.

In step S109, it is determined whether the plurality of course angle installation errors are stable; if yes, go to step S110; if not, step S105 is performed.

In a specific embodiment, whether the installation errors of the M course angles are stable or not can be judged by a moving average method; if the M course angle installation errors are stable, executing the step S110; if the M course angle installation errors are unstable, step S105 is executed.

In step S110, a course angle mounting error of the inertial measurement unit is determined according to the plurality of course angle mounting errors.

In one embodiment, if the M course angle installation errors are stable, an average of the M course angle installation errors may be calculated, and the average of the M course angle installation errors is determined to be the course angle installation error of the inertial measurement unit.

In step S111, the pitch angle installation error, roll angle installation error, and course angle installation error of the inertial measurement unit are configured to the autopilot system.

In a specific embodiment, the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertial measurement unit may be fed back to the autopilot system, and the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertial measurement unit may be configured in a configuration file corresponding to the autopilot system. The automatic driving system can compensate the pitch angle, the roll angle and the course angle of the vehicle in the inertial navigation resolving process by utilizing the pitch angle installation error, the roll angle installation error and the course angle installation error in the configuration file, and the accuracy of navigation information of the inertial navigation system is improved.

The method for calibrating the installation error angle of the inertial measurement unit can calibrate the installation error angle of the inertial measurement unit by using the measurement data of the inertial measurement unit and the positioning data of the satellite positioning module under different motion states of a vehicle, does not need specific calibration equipment, is simple and convenient to operate, can conveniently calibrate the installation error angle of the inertial measurement unit, improves the efficiency of calibrating the installation error angle of the inertial measurement unit, can enable the inertial measurement unit to provide measurement data with higher precision, improves the precision of positioning and navigation of the inertial measurement unit, and reduces the positioning and navigation errors caused by the installation error of the inertial measurement unit.

Example two:

fig. 2 is another schematic flow chart of an installation error angle calibration method of an inertial measurement unit according to an embodiment of the present application.

Referring to fig. 2, a method for calibrating an installation error angle of an inertial measurement unit, which is applied to a server, includes:

in step S201, when the vehicle is in the first state, the vehicle-mounted intelligent device obtains and uploads multiple sets of first measurement data of the inertial measurement unit, and when the vehicle is in the second state, the vehicle-mounted intelligent device obtains and uploads multiple sets of second measurement data of the inertial measurement unit and multiple sets of positioning data of the satellite positioning module.

In one embodiment, the vehicle-mounted intelligent device of the autonomous vehicle can acquire and upload multiple sets of first measurement data of the inertia measurement unit to the remote server when the vehicle is in a first state; and when the vehicle is in the second state, the plurality of groups of second measurement data of the inertial measurement unit and the plurality of groups of positioning data of the satellite positioning module are acquired and uploaded to the remote server. The remote server can receive multiple groups of first measurement data, multiple groups of second measurement data and multiple groups of positioning data of the satellite positioning module of the inertia measurement unit uploaded by the vehicle-mounted intelligent device.

The method comprises the steps that when a vehicle is in a first state, vehicle-mounted intelligent equipment obtains multiple groups of first measurement data of an inertia measurement unit; when the vehicle is in the second state, the process of acquiring the plurality of sets of second measurement data of the inertial measurement unit and the plurality of sets of positioning data of the satellite positioning module may refer to the description of steps S101 and S105, which is not described herein again.

In step S202, a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertial measurement unit are obtained according to a plurality of sets of acceleration data of a plurality of sets of first measurement data, the pitch angle installation errors and the roll angle installation errors of the inertial measurement unit are respectively determined according to the plurality of pitch angle installation errors and the plurality of roll angle installation errors, a plurality of first course angles of the vehicle are obtained according to a plurality of sets of second measurement data, a plurality of second course angles of the vehicle are obtained according to a plurality of sets of positioning data, a plurality of course angle installation errors of the inertial measurement unit are obtained according to the plurality of first course angles and the plurality of second course angles, and the course angle installation errors of the inertial measurement unit are determined according to the plurality of course angle installation errors.

In a specific embodiment, the vehicle-mounted intelligent device of the autonomous vehicle may upload the acquired multiple sets of first measurement data of the inertial measurement unit, the multiple sets of second measurement data, and the multiple sets of positioning data of the satellite positioning module to the server. The server receives multiple groups of first measurement data, multiple groups of second measurement data and multiple groups of positioning data of the satellite positioning module, wherein the multiple groups of first measurement data and the multiple groups of second measurement data are uploaded by the vehicle-mounted intelligent equipment; obtaining a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertia measurement unit according to a plurality of groups of acceleration data of a plurality of groups of first measurement data; respectively determining a pitch angle installation error and a roll angle installation error of an inertia measurement unit according to the plurality of pitch angle installation errors and the plurality of roll angle installation errors; obtaining a plurality of first course angles of the vehicle according to the plurality of groups of second measurement data, and obtaining a plurality of second course angles of the vehicle according to the plurality of groups of positioning data; obtaining a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles; and determining the course angle installation error of the inertial measurement unit according to the plurality of course angle installation errors.

In a specific embodiment, the process of determining the pitch angle installation error, the roll angle installation error and the heading angle installation error of the inertial measurement unit by the server may refer to the description of fig. 1, and details are not repeated here.

In step S203, the pitch angle installation error, the roll angle installation error, and the course angle installation error of the inertial measurement unit are sent to the vehicle-mounted intelligent device.

In one embodiment, the server may send the determined pitch angle installation error, roll angle installation error, and course angle installation error of the inertial measurement unit to an onboard intelligent device of the autonomous vehicle. The vehicle-mounted intelligent equipment can receive a pitch angle installation error, a roll angle installation error and a course angle installation error of the inertia measurement unit sent by the server; and configuring the received pitch angle installation error, roll angle installation error and course angle installation error of the inertial measurement unit into a configuration file corresponding to the automatic driving system. The automatic driving system can compensate the pitch angle, the roll angle and the course angle of the vehicle in the inertial navigation resolving process by utilizing the pitch angle installation error, the roll angle installation error and the course angle installation error in the configuration file, and the accuracy of navigation information of the inertial navigation system is improved.

The method for calibrating the installation error angle of the inertial measurement unit, provided by the embodiment of the application, uploads a plurality of groups of first measurement data, a plurality of groups of second measurement data and a plurality of groups of positioning data of the satellite positioning module of the inertial measurement unit when a vehicle is in different motion states, and determines the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertial measurement unit according to the plurality of groups of first measurement data, the plurality of groups of second measurement data and the plurality of groups of positioning data of the satellite positioning module by the server, thereby reducing the consumption of the installation error angle calibration of the inertial measurement unit on vehicle-mounted intelligent equipment resources, improving the calculation processing speed of the installation error angle calibration of the inertial measurement unit, and moreover, specific calibration equipment is not needed, the operation is simple and convenient, the installation error angle of the inertia measurement unit can be conveniently calibrated, and the efficiency of calibrating the installation error angle of the inertia measurement unit is improved.

Example three:

corresponding to the embodiment of the application function implementation method, the application also provides an inertial measurement unit installation error angle calibration device, a vehicle-mounted intelligent device, a system, an electronic device and corresponding embodiments.

Fig. 3 is a schematic structural diagram of an installation error angle calibration device of an inertial measurement unit according to an embodiment of the present application.

Referring to fig. 3, an inertial measurement unit installation error angle calibration apparatus includes an original data acquisition module 301, a first error module 302, an error determination module 303, a heading angle acquisition module 304, a second error module 305, and a configuration module 306.

The raw data acquiring module 301 is configured to acquire multiple sets of first measurement data of the inertial measurement unit when the vehicle is in a first state, and acquire multiple sets of second measurement data of the inertial measurement unit and multiple sets of positioning data of the satellite positioning module when the vehicle is in a second state.

In a specific embodiment, when the vehicle is in a horizontal uniform speed state, the original data obtaining module 301 obtains K sets of acceleration data on three axes of K sets of three-axis accelerometers according to a set time, where K is an integer greater than 1, and the acceleration data at the kth time

。

In one embodiment, the autonomous vehicle is further equipped with a satellite positioning module, which may include, but is not limited to, at least one of a GPS satellite module, a beidou satellite positioning module, an RTK satellite positioning module, and the like.

In one embodiment, when the vehicle runs on a straight road and keeps running in a fixed direction, the vehicle is in a horizontal running state, and the raw data acquisition module 301 can acquire M sets of positioning data of the RTK satellite positioning module, M sets of three-axis acceleration and three-axis angular velocity of the inertial measurement unit at any time.

In one embodiment, the linear distance between the positioning data at the M-1 th time and the positioning data at the M-th time in the M groups of positioning data of the RTK satellite positioning module acquired by the raw data acquisition module 301 may be greater than 3 meters.

It should be noted that the M sets of positioning data of the RTK satellite positioning module acquired by the raw data acquisition module 301 and the M sets of three-axis acceleration and three-axis angular velocity of the inertial measurement unit are aligned in time and space.

The first error module 302 is configured to obtain a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertial measurement unit according to a plurality of sets of acceleration data of the plurality of sets of first measurement data obtained by the raw data obtaining module 301.

In the formula (I), wherein,

and g is the earth gravity acceleration value.

The first error module 302 may obtain the acceleration data at the kth time actually output by the MPU-6050 triaxial accelerometer, which is obtained by the raw data obtaining module 301

Calculating the pitch angle mounting error theta of the inertial measurement unit at the kth time_kTransverse roll angle installation error phi_k。

The first error module 302 may obtain a kth pitch angle mounting error according to acceleration data at a kth time:

the first error module 302 may obtain a kth roll angle mounting error from acceleration data at a kth time:

in one embodiment, the first error module 302 may calculate K pitch angle installation errors and K roll angle installation errors based on K sets of acceleration data.

An error determining module 303, configured to determine a pitch angle installation error and a roll angle installation error of the inertial measurement unit according to the multiple pitch angle installation errors and the multiple roll angle installation errors obtained by the first error module 302.

In a specific embodiment, the error determining module 303 may determine whether the K pitch angle installation errors and the K roll angle installation errors obtained by the first error module 302 are stable through a sliding average method; if the error determination module 303 determines that the K pitch angle installation errors and the K roll angle installation errors are stable, the pitch angle installation errors and the roll angle installation errors of the inertia measurement unit can be respectively determined according to the plurality of pitch angle installation errors and the plurality of roll angle installation errors; if the error determination module 303 determines that the K pitch angle installation errors and the K roll angle installation errors are unstable, the original data acquisition module 301, the first error module 302, and the error determination module 303 are continuously executed until the error determination module 303 determines that the K pitch angle installation errors and the K roll angle installation errors are stable.

In a specific embodiment, if the error determination module 303 determines that the K pitch angle installation errors and the K roll angle installation errors are stable, the error determination module 303 may calculate an average value of the K pitch angle installation errors and an average value of the K roll angle installation errors, respectively, determine that the average value of the K pitch angle installation errors is the pitch angle installation error of the inertial measurement unit, and determine that the average value of the K roll angle installation errors is the roll angle installation error of the inertial measurement unit.

The course angle obtaining module 304 is configured to obtain a plurality of first course angles of the vehicle according to the plurality of sets of second measurement data obtained by the raw data obtaining module 301, and obtain a plurality of second course angles of the vehicle according to the plurality of sets of positioning data obtained by the raw data obtaining module.

In one embodiment, the inertial navigation system may update the attitude matrix of the inertial navigation system at the m-th moment according to the three-axis acceleration and the three-axis angular velocity at the m-th moment, the attitude matrix at the m-1 th moment, and the rotation matrix among the carrier coordinate system, the geographic coordinate system, the inertial coordinate system, and the inertial navigation coordinate system. The heading angle obtaining module 304 may obtain the first heading angle Ψ at the m-th time of the vehicle according to the attitude matrix at the m-th time of the inertial navigation system_I,m. The heading angle obtaining module 304 can obtain M first heading angles of the vehicle according to the M sets of three-axis accelerations and three-axis angular velocities.

In one embodiment, the RTK satellite positioning module may obtain the second heading angle Ψ at the mth time of the vehicle according to the positioning data at the mth time_W,m. Course angle acquisitionThe module 304 may obtain M second heading angles of the vehicle according to the M sets of positioning data.

The second error module 305 is configured to obtain a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles obtained by the course angle obtaining module 304.

In one embodiment, the second error module 305 determines a first heading angle Ψ for the m-th time of the vehicle_I,mSecond heading angle psi from m-th moment_W,mAnd performing difference making to obtain the course angle installation error at the mth moment. The second error module 305 obtains M course angle installation errors according to M first course angles and M second course angles of the vehicle.

The error determination module 303 is further configured to determine a course angle installation error of the inertial measurement unit according to the plurality of course angle installation errors obtained by the second error module 305.

In a specific embodiment, the error determining module 303 may determine whether the installation errors of the M heading angles are stable through a moving average method; if the error determining module 303 determines that the M course angle installation errors are stable, determining course angle installation errors of the inertial measurement unit according to the plurality of course angle installation errors; if the M course angle installation errors are unstable, the original data acquisition module 301, the course angle acquisition module 304, the second error module 305 and the error determination module 303 are continuously executed until the error determination module 303 judges that the M course angle installation errors are stable.

In one embodiment, if the error determination module 303 determines that the M course angle installation errors are stable, an average of the M course angle installation errors may be calculated, and the average of the M course angle installation errors is determined as the course angle installation error of the inertial measurement unit.

And the configuration module 306 is used for configuring the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertial measurement unit determined by the error determination module 303 to the automatic driving system.

In one embodiment, the configuration module 306 may feed back the pitch angle installation error, the roll angle installation error, and the course angle installation error of the inertial measurement unit determined by the error determination module 303 to the autopilot system, and configure the pitch angle installation error, the roll angle installation error, and the course angle installation error of the inertial measurement unit to a configuration file corresponding to the autopilot system. The automatic driving system can compensate the pitch angle, the roll angle and the course angle of the vehicle in the inertial navigation resolving process by utilizing the pitch angle installation error, the roll angle installation error and the course angle installation error in the configuration file, and the accuracy of navigation information of the inertial navigation system is improved.

The technical scheme shown in the embodiment of the application can utilize the measurement data of the inertial measurement unit and the positioning data of the satellite positioning module to calibrate the installation error angle of the inertial measurement unit when the vehicle is in different motion states, no specific calibration equipment is needed, the operation is simple and convenient, the installation error angle of the inertial measurement unit can be conveniently calibrated, the efficiency of calibrating the installation error angle of the inertial measurement unit is improved, the inertial measurement unit can provide measurement data with higher precision, the positioning and navigation precision of the inertial measurement unit is improved, and the positioning and navigation errors caused by the installation error of the inertial measurement unit are reduced.

Example four:

fig. 4 is a schematic structural diagram of a server according to an embodiment of the present application.

Referring to fig. 4, a server includes a receiving unit 401, a first error unit 402, an error determining unit 403, a heading angle acquiring unit 404, a second error unit 405, and a transmitting unit 406.

The receiving unit 401 is configured to receive multiple sets of first measurement data of the inertial measurement unit, which are acquired and uploaded by the vehicle-mounted intelligent device when the vehicle is in the first state, and receive multiple sets of second measurement data of the inertial measurement unit and multiple sets of positioning data of the satellite positioning module, which are acquired and uploaded by the vehicle-mounted intelligent device when the vehicle is in the second state.

In one embodiment, the vehicle-mounted smart device of the autonomous vehicle may acquire and upload multiple sets of first measurement data of the inertia measurement unit to the receiving unit 401 when the vehicle is in the first state; when the vehicle is in the second state, the multiple sets of second measurement data of the inertial measurement unit and the multiple sets of positioning data of the satellite positioning module, which are obtained and uploaded, are transmitted to the receiving unit 401. The receiving unit 401 can receive multiple sets of first measurement data, multiple sets of second measurement data, and multiple sets of positioning data of the satellite positioning module of the inertia measurement unit uploaded by the vehicle-mounted intelligent device.

The method comprises the steps that when a vehicle is in a first state, vehicle-mounted intelligent equipment obtains multiple groups of first measurement data of an inertia measurement unit; when the vehicle is in the second state, reference may be made to the description of steps S101 and S105 in fig. 1 for a process of acquiring multiple sets of second measurement data of the inertial measurement unit and multiple sets of positioning data of the satellite positioning module, which is not described herein again. .

A first error unit 402, configured to obtain a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertial measurement unit according to a plurality of sets of acceleration data of the plurality of sets of first measurement data received by the receiving unit 401.

An error determination unit 403, configured to determine a pitch angle installation error and a roll angle installation error of the inertial measurement unit according to the multiple pitch angle installation errors and the multiple roll angle installation errors obtained by the first error unit 402;

the heading angle obtaining unit 404 is configured to obtain a plurality of first heading angles of the vehicle according to the plurality of sets of second measurement data received by the receiving unit 401, and obtain a plurality of second heading angles of the vehicle according to the plurality of sets of positioning data received by the receiving unit 401.

And the second error unit 405 is configured to obtain a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles obtained by the course angle obtaining unit 404.

And the error determination unit 403 is further configured to determine a course angle installation error of the inertial measurement unit according to the plurality of course angle installation errors obtained by the second error unit 405.

In a specific embodiment, the first error unit 402 obtains a plurality of pitch angle installation errors and a plurality of roll angle installation errors of the inertial measurement unit according to a plurality of sets of acceleration data of a plurality of sets of first measurement data received by the receiving unit 401; the error determination unit 403 determines the pitch angle installation error and the roll angle installation error of the inertial measurement unit respectively according to the multiple pitch angle installation errors and the multiple roll angle installation errors obtained by the first error unit 402; the course angle obtaining unit 404 obtains a plurality of first course angles of the vehicle according to the plurality of sets of second measurement data received by the receiving unit 401, and obtains a plurality of second course angles of the vehicle according to the plurality of sets of positioning data received by the receiving unit 401; the second error unit 405 obtains a plurality of course angle installation errors of the inertial measurement unit according to the plurality of first course angles and the plurality of second course angles obtained by the course angle obtaining unit 404; the error determination unit 403 determines the course angle mounting error of the inertial measurement unit from the plurality of course angle mounting errors obtained by the second error unit 405.

And a sending unit 406, configured to send the pitch angle installation error, the roll angle installation error, and the heading angle installation error of the inertial measurement unit determined by the error determination unit 403 to the vehicle-mounted intelligent device.

In one embodiment, the sending unit 406 may send the pitch angle installation error, roll angle installation error, and course angle installation error of the inertial measurement unit determined by the error determination unit 403 to an onboard intelligent device of the autonomous vehicle. The vehicle-mounted intelligent device can receive the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertia measurement unit sent by the sending unit 406; and configuring the received pitch angle installation error, roll angle installation error and course angle installation error of the inertial measurement unit into a configuration file corresponding to the automatic driving system. The automatic driving system can compensate the pitch angle, the roll angle and the course angle in the inertial navigation resolving process by utilizing the pitch angle installation error, the roll angle installation error and the course angle installation error in the configuration file, so that the navigation information precision of the inertial navigation system is improved.

The technical scheme provided by the embodiment of the application uploads a plurality of groups of first measurement data, a plurality of groups of second measurement data and a plurality of groups of positioning data of the satellite positioning module of the inertia measurement unit when the vehicle is in different motion states to the server, and the server determines the pitch angle installation error, the roll angle installation error and the course angle installation error of the inertia measurement unit according to the plurality of groups of first measurement data, the plurality of groups of second measurement data and the plurality of groups of positioning data of the satellite positioning module of the inertia measurement unit, thereby reducing the consumption of vehicle-mounted intelligent equipment resources by the installation error angle calibration of the inertia measurement unit, improving the calculation processing speed of the installation error angle calibration of the inertia measurement unit, and moreover, specific calibration equipment is not needed, the operation is simple and convenient, the installation error angle of the inertia measurement unit can be conveniently calibrated, and the efficiency of calibrating the installation error angle of the inertia measurement unit is improved.

Example five:

fig. 5 is a schematic structural diagram of an installation error angle calibration system of an inertial measurement unit according to an embodiment of the present application.

Referring to fig. 5, an inertial measurement unit installation error angle calibration system includes the above-mentioned vehicle-mounted intelligent device 501 and a server 502.

The vehicle-mounted intelligent device 501 is used for acquiring multiple groups of first measurement data of the inertia measurement unit when the vehicle is in a first state, acquiring multiple groups of second measurement data of the inertia measurement unit and multiple groups of positioning data of the satellite positioning module when the vehicle is in a second state, uploading the multiple groups of first measurement data, the multiple groups of second measurement data and the multiple groups of positioning data to the server 502, and receiving a pitch angle installation error, a roll angle installation error and a course angle installation error of the inertia measurement unit sent by the server 502.

In one embodiment, the server 502 may be a remote cloud server, and the server 502 and the in-vehicle smart device 501 are connected wirelessly or through a wire. The vehicle-mounted intelligent device 501 of the autonomous vehicle can acquire and upload multiple groups of first measurement data of the inertia measurement unit to the server 502 when the vehicle is in the first state; the sets of second measurement data of the inertial measurement unit and the sets of positioning data of the satellite positioning module that can be obtained and uploaded to the server 502 can be obtained when the vehicle is in the second state.

In a specific embodiment, the vehicle-mounted intelligent device 501 of the autonomous vehicle may receive a pitch angle installation error, a roll angle installation error, and a course angle installation error of the inertia measurement unit sent by the server 502; and feeding back the received pitch angle installation error, roll angle installation error and course angle installation error of the inertial measurement unit to the automatic driving system, and configuring the pitch angle installation error, roll angle installation error and course angle installation error of the inertial measurement unit to a configuration file corresponding to the automatic driving system. The automatic driving system can compensate the pitch angle, the roll angle and the course angle in the inertial navigation resolving process by utilizing the pitch angle installation error, the roll angle installation error and the course angle installation error in the configuration file, so that the navigation information precision of the inertial navigation system is improved.

A server 502, configured to receive multiple sets of first measurement data, multiple sets of second measurement data, and multiple sets of positioning data uploaded by the vehicle-mounted smart device 501, obtain multiple pitch angle installation errors and multiple roll angle installation errors of the inertial measurement unit according to the multiple sets of acceleration data of the multiple sets of first measurement data, respectively determine the pitch angle installation errors and the roll angle installation errors of the inertial measurement unit according to the multiple pitch angle installation errors and the multiple roll angle installation errors of the inertial measurement unit, obtain multiple first course angles of the vehicle according to the multiple sets of second measurement data, obtain multiple second course angles of the vehicle according to the multiple sets of positioning data, obtain multiple course angle installation errors of the inertial measurement unit according to the multiple first course angles and the multiple second course angles, determine the course angle installation error of the inertial measurement unit according to the multiple course angle installation errors, and send the pitch angle installation error, the course angle installation error, the multiple roll angle installation error, and the roll angle installation error of the inertial measurement unit, And (4) transmitting the roll angle installation error and the course angle installation error to the vehicle-mounted intelligent equipment 501.

The specific manner in which each module performs operations has been described in detail in the embodiments related to the method, and will not be elaborated herein.

Example six:

Referring to fig. 6, the electronic device 60 includes a memory 601 and a processor 602.

The Processor 602 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 601 may include various types of storage units, such as system memory, Read Only Memory (ROM), and permanent storage. Wherein the ROM may store static data or instructions for the processor 602 or other modules of the computer. The persistent storage device may be a read-write storage device. The persistent storage may be a non-volatile storage device that does not lose stored instructions and data even after the computer is powered off. In some embodiments, the persistent storage device employs a mass storage device (e.g., magnetic or optical disk, flash memory) as the persistent storage device. In other embodiments, the permanent storage may be a removable storage device (e.g., floppy disk, optical drive). The system memory may be a read-write memory device or a volatile read-write memory device, such as a dynamic random access memory. The system memory may store instructions and data that some or all of the processors require at runtime. In addition, the memory 601 may include any combination of computer-readable storage media, including various types of semiconductor memory chips (DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), magnetic and/or optical disks, may also be employed. In some embodiments, memory 601 may include a removable storage device that is readable and/or writable, such as a Compact Disc (CD), a digital versatile disc read only (e.g., DVD-ROM, dual layer DVD-ROM), a Blu-ray disc read only, an ultra-dense disc, a flash memory card (e.g., SD card, min SD card, Micro-SD card, etc.), a magnetic floppy disk, or the like. Computer-readable storage media do not contain carrier waves or transitory electronic signals transmitted by wireless or wired means.

The memory 601 has stored thereon executable code that, when processed by the processor 602, may cause the processor 602 to perform some or all of the methods described above.

Furthermore, the method according to the present application may also be implemented as a computer program or computer program product comprising computer program code instructions for performing some or all of the steps of the above-described method of the present application.

Alternatively, the present application may also be embodied as a non-transitory machine-readable storage medium (or computer-readable storage medium, or machine-readable storage medium) having stored thereon executable code (or a computer program, or computer instruction code) which, when executed by a processor of an electronic device (or electronic device, server, etc.), causes the processor to perform some or all of the various steps of the above-described methods in accordance with the present application.

Having described embodiments of the present application, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. An inertial measurement unit installation error angle calibration method is characterized by comprising the following steps:

2. The method of claim 1, wherein determining the pitch angle installation error and the roll angle installation error of the inertial measurement unit from the plurality of pitch angle installation errors and the plurality of roll angle installation errors, respectively, comprises:

3. The method of claim 1, wherein determining a course angle fix error of the inertial measurement unit from the plurality of course angle fix errors comprises:

4. The method according to any one of claims 1-3, further comprising:

5. An inertial measurement unit installation error angle calibration method is applied to a server and comprises the following steps:

6. The utility model provides an inertial measurement unit installation error angle calibration device which characterized in that includes:

7. The apparatus of claim 6, further comprising:

8. A server, comprising:

9. An inertial measurement unit installation error angle calibration system, characterized by comprising the vehicle-mounted intelligent device as claimed in claim 8 and a server;

10. A non-transitory machine-readable storage medium having executable code stored thereon, which when executed by a processor of an electronic device, causes the processor to perform the method of any one of claims 1-5.