Method and device for acquiring an initial heading angle of an inclination measurement

Abstract

The application discloses a kind of acquisition method and device of initial heading angle of tilt measurement, the method includes: the initialization of heading angle;After heading angle enters initialization mode, the position relationship formula of the ground point corresponding to the bottom of measuring rod and the center point of inertial measurement unit is solved to obtain initial heading angle.The application is solved by the position relationship formula of the ground point corresponding to the bottom of measuring rod and the center point of inertial measurement unit, and the initial heading angle in tilt measurement can be quickly and accurately obtained, and the accuracy of the heading angle solved is not influenced by experience weight value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of RTK tilt measurement, and particularly relates to a method and device for obtaining an initial heading angle in tilt measurement. BACKGROUND

[0002] In MEMS-INS assisted tilt RTK measurement technology, the position of a measurement rod is compensated for tilt by using the position of an RTK measurement device and the attitude information of a GNSS / INS combination to obtain the position coordinates of a ground point. Before the measurement rod is compensated for tilt, an accurate initial heading angle needs to be obtained.

[0003] In conventional MEMS-INS assisted tilt RTK technology, the initial heading angle is determined by the following method: for example, a matching method based on RTK trajectories and INS trajectories. By keeping the bottom of the measurement rod stationary and shaking the top end, the position calculated by the RTK is projected to the center of the inertial measurement unit to form an RTK trajectory; at the same time, the position of the center of the inertial measurement unit is calculated by the inertial measurement unit to form an inertial measurement unit trajectory. By matching the points corresponding to the RTK trajectory and the inertial measurement unit trajectory at the same epoch, a set of RTK / INS position vectors is formed. Different weights are assigned to the angles of the obtained pairs of vector sets, the initial heading angle error is calculated, and the initial heading angle is determined. The matching method based on the RTK trajectory and the INS trajectory described above is simple to implement, but it is necessary to assign certain weights to the angles of the GNSS / INS trajectories at different times to determine the initial heading angle, and the accuracy of the initial heading angle is affected by the experience weight value. SUMMARY

[0004] In view of the above technical problems, the purpose of the present application is to provide a method and device for obtaining an initial heading angle in tilt measurement, which solves the problem that the accuracy of the method for determining the initial heading angle in conventional tilt RTK technology is easily affected by the experience weight value.

[0005] To solve the above problems, the present application is implemented by the following technical solutions:

[0006] In a first aspect, the embodiments of the present application disclose a method for obtaining an initial heading angle in tilt measurement, comprising:

[0007] After the heading angle enters the initialization mode, the initial heading angle is obtained by solving the position relationship formula of the ground point corresponding to the bottom of the measurement rod and the center point of the inertial measurement unit. The initial heading angle Wherein, ψ is the initial heading angle.

[0008] The position relationship formula of the ground point corresponding to the bottom of the measurement rod and the center point of the inertial measurement unit satisfies the following formula:

[0009]

[0010] wherein, is the position of the IMU center point; is the velocity of the IMU center point; t = [P t e P t n P t u T is the position of the measuring rod tip; V t = [V t e V t n V t u T is the velocity of the measuring rod tip; is the rod arm value from the IMU center point to the measuring rod tip; is the projection of the gyro data in the b frame relative to the n frame in the b frame, the output data of the gyro, is the projection of the gyro data in the n frame relative to the i frame in the b frame; is the conversion matrix from the n frame to the b frame.

[0011] Optionally, the method further comprises: initializing the heading angle.

[0012] The step of initializing the heading angle comprises:

[0013] keeping the measuring rod length and the position of the ground point corresponding to the bottom of the measuring rod unchanged, and changing the position and velocity of the top end of the measuring rod. Optionally, the step of initializing the heading angle further comprises:

[0014] judging whether the heading angle has entered the initialization mode through a first chi-square distribution detection model.

[0015] Optionally, the first chi-square distribution detection model satisfies the following formula:

[0016]

[0017] wherein, represents the residual sum of squares of the velocity in the horizontal direction of n ephemeris; represents the residual sum of squares of the velocity in the zenith direction of n ephemeris; Chi_square represents chi-square distribution; stat is a state detection quantity, 1 represents passing the detection, 0 represents failing the detection, and n is a natural number.

[0018] ​​Optionally, the inertial measurement unit center point horizontal direction velocity residual square sum and the zenith direction velocity residual satisfy the following formula:

[0019]

[0020] wherein, respectively represent the horizontal direction velocity residual and the zenith direction velocity residual.

[0021] Optionally, the method further comprises: judging the initial heading angle accuracy according to a second chi-square distribution detection model.

[0022] Optionally, the second chi-square distribution detection model satisfies the following formula:

[0023]

[0024] wherein, represents the n ephemeris east direction position residual square sum; represents the n ephemeris north direction position residual square sum; Chi_square represents chi-square distribution; stat is a state detection quantity, 1 represents passing detection, 0 represents failing detection, and n is a natural number.

[0025] Optionally, the judging the initial heading angle accuracy according to the second chi-square distribution detection model comprises:

[0026] After the heading angle enters the initialization mode, the n ephemeris east direction position residual square sum and the n ephemeris north direction position residual square sum of the inertial measurement unit center point are respectively subjected to chi-square distribution detection, n is a natural number; when the n ephemeris east direction position residual square sum and the n ephemeris north direction position residual square sum are subjected to chi-square distribution detection, and the chi-square detection is passed, it is judged that the initial heading angle satisfies the accuracy requirement.

[0027] In a second aspect, the embodiments of the present application disclose an acquisition device for measuring an initial heading angle, comprising:

[0028] An initialization module is configured to initialize the heading angle.

[0029] An initial heading angle calculation module is configured to, after the heading angle enters the initialization mode, obtain the initial heading angle by solving a position relationship formula of a ground point corresponding to a bottom of a measuring rod and an inertial measurement unit center point, wherein the initial heading angle wherein, ψ is the initial heading angle.

[0030] The position relationship formula of the ground point corresponding to the bottom of the measuring rod and the inertial measurement unit center point satisfies the following formula:

[0031]

[0032] wherein, is the position of the IMU center point; is the velocity of the IMU center point; t = [P t e P t n P t u ] T is the position of the measuring rod tip; t = [V t e V t n V t u ] T is the velocity of the measuring rod tip; is the rod arm value from the IMU center point to the measuring rod tip; is the projection of the gyro data in the b frame relative to the n frame in the b frame, the output data of the gyro, is the projection of the gyro data in the n frame relative to the i frame in the b frame; is the conversion matrix from the n frame to the b frame.

[0033] In a third aspect, the embodiments of the present application disclose a computer storage medium, which stores a computer program, and the computer program is executed by a processor to realize the method for obtaining an initial heading angle in tilt measurement.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] The present application can quickly and accurately obtain the initial heading angle in tilt measurement by solving the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the IMU center point, and the accuracy of the obtained heading angle is not affected by the experience weight value.

[0036] Further, the initialization is performed by keeping the bottom end of the measuring rod stationary and pushing the measuring rod back and forth. The length of the measuring rod, the position of the touch point at the bottom end of the measuring rod, and the characteristics that the position and velocity of the touch point do not change when the measuring rod is shaken are used as constraint conditions. The position and velocity information of the IMU center point at the top end of the measuring rod at multiple epochs are used to obtain the initial value of the heading angle by the principle of resection. The initialization method is simple and flexible, and the initialization time is relatively short. The limitation on the initialization site is relatively small. For example, the initialization can be completed by placing the bottom end of the measuring rod on a ground point and shaking it, without the need for the measurement personnel to hold the instrument and walk straight for a distance to perform the initialization operation. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A flowchart of an acquisition method of an initial heading angle of an inclination measurement according to an embodiment of the present application is provided;

[0038] Figure 2 A structural diagram of an acquisition device of an initial heading angle of an inclination measurement according to another embodiment of the present application is provided;

[0039] Figure 3 A structural diagram of an electronic device according to another embodiment of the present application is provided. DETAILED DESCRIPTION

[0040] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments described below or technical features thereof can be combined with each other to form new embodiments without conflict:

[0041] Embodiment one:

[0042] Please refer to Figure 1 , which shows an acquisition method of an initial heading angle of an inclination measurement according to the present application, which comprises:

[0043] Step S1: initializing the heading angle;

[0044] It should be noted that the RTK (Real-time kinematic, real-time dynamic differential method) positioning technology is a real-time dynamic positioning technology based on carrier phase observation values. The RTK positioning technology can provide real-time three-dimensional positioning results of a measurement point in a specified coordinate system and achieve centimeter-level accuracy. The device for implementing GPS measurement based on the RTK positioning technology is called an RTK measurement device. The RTK measurement device includes a measurement rod and an inertial measurement unit, and the inertial measurement unit includes a device for measuring the three-axis attitude angle (or angular velocity) and acceleration of an object. In the RTK operation mode, the reference station transmits its observation values and measurement point coordinate information to the mobile station through the data link. The mobile station not only receives data from the reference station through the data link, but also collects GPS observation data, and forms a differential observation value in the system for real-time processing, while giving a centimeter-level positioning result in less than one second.

[0045] In actual application, the RTK system can be first released from fixation, and the tilt RTK measurement mode is selected according to the inclination angle of the measurement rod of the RTK system placed at the observation point and in the measurement position. When the tilt RTK measurement mode is selected, the measurement rod in the RTK system is shaken to initialize the heading angle. During the process of initializing the heading angle, the rod tip of the measurement rod is kept stationary, and the top end of the measurement rod is shaken.

[0046] Step S2: after entering the initialization mode at the heading angle, an initial heading angle is obtained by measuring the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit, and the initial heading angle is wherein, ψ is the initial heading angle;

[0047] The position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit satisfies the following formula:

[0048]

[0049] wherein, wherein, is the position of the center point of the inertial measurement unit; is the velocity of the center point of the inertial measurement unit; P t = [P t e P t n P t u ] T is the position of the tip of the measuring rod; V t = [V t e V t n V t u ] T is the velocity of the tip of the measuring rod; is the arm value of the center point of the inertial measurement unit to the tip of the measuring rod; is the projection of the gyro data in the b system relative to the n system in the b system, the output data of the gyro, is the projection of the gyro data in the n system relative to the i system in the b system; is the conversion matrix of the n system to the b system.

[0050] It should be noted that i is the inertial coordinate system, the origin is at the center of the earth, the x axis is in the equatorial plane of the earth, the z axis is along the rotation axis of the earth, and the y axis forms a right-handed orthogonal coordinate system with the x and z axes; b is defined as the carrier coordinate system, the origin is at the center of gravity of the inertial measurement unit, the y axis is along the longitudinal axis of the inertial device, pointing in the forward direction, the z axis points to the top of the inertial device, and the x axis points to the right direction of the inertial device; n is the geographical coordinate system, which is an east-north-sky orthogonal coordinate system defined relative to the geodetic surface, denoted as ENU, the origin is the projection of the inertial platform origin on the geodetic surface, the E axis points horizontally to the east, the N axis points to the true north direction, and the U axis is perpendicular to the reference ellipsoid and points to the outside of the earth; the b system is first rotated by ψ angle around the z axis, secondly rotated by θ angle around the y axis after the first rotation, and thirdly rotated by γ angle around the x axis after the second rotation, so as to obtain the conversion matrix of the b system to the n system That is,

[0051]

[0052] It should be noted that the inertial measurement unit is a device for measuring the three-axis attitude angle (or angular rate) and acceleration of an object. An inertial measurement unit includes three single-axis accelerometers and three single-axis gyroscopes. The accelerometer detects the acceleration signal of the object in the independent three-axis coordinate system of the carrier.

[0053] Specifically, the initial heading angle is obtained by solving the position relationship formula of the corresponding ground point at the bottom of the measuring rod and the center point of the inertial measurement unit. The steps are as follows:

[0054] Let ψ be the heading angle, θ be the pitch angle, and γ be the roll angle. We have:

[0055]

[0056] During the initialization of the heading angle, the ground point contacted by the rod tip of the measuring rod is kept stationary, and the top end of the measuring rod is shaken. At this time, V t = 0, and the position of the IMU center at the top end of the rod changes within a small range. At this time, the effects of the earth's curvature and the earth's rotation can be ignored, i.e. as a small quantity that can be ignored. Then the velocity formula of the ground point contacted by the rod tip and the IMU center point in formula (1) can be rewritten as Expanding it gives:

[0057]

[0058] Where:

[0059] Taking the square of the velocity of the IMU center point in the east and north directions and adding them together gives:

[0060]

[0061] Substituting each term of into C 11 C 12 +C 21 C 22 We have:

[0062]

[0063] Substituting formula (5) into formula (4) gives:

[0064]

[0065] At the same time, the velocity of the IMU center point in the zenith direction has the equation:

[0066]

[0067] The position relationship formula corresponding to the ground point at the bottom of the measuring rod and the IMU center point in formula (1) is expanded to obtain:

[0068]

[0069] Wherein: is the conversion matrix of n system to h system, is the conversion matrix of h system to b system.

[0070] It can be known from formula (10) that the position P m of the IMU center is a known parameter, and P t is the coordinate of the ground point which does not change in the shaking process, and cos(ψ) and sin(ψ) are unknown parameters, The value of each epoch can be solved by the AHRS (attitude heading reference system) navigation algorithm, and the rod arm value is a known parameter, and formula (10) is transformed into the least square form:

[0071]

[0072] Wherein: X=[P t e P t n sin(ψ) cos(ψ)] T .

[0073] In the shaking process, the unknown parameters are solved by using the least square method with the data of at least n (≥3) epochs, that is:

[0074] X=(A T A) -1 A T V (12)

[0076] Then the initial heading angle is:

[0077]

[0078] In the tilt measurement technology of inertial navigation RTK, the high-precision initial heading angle is the key to obtain high-precision measurement points. In the above implementation process, the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit is solved, so that the initial heading angle in the tilt measurement initialization process can be quickly and accurately obtained.

[0079] Optionally, the step of initializing the heading angle comprises:

[0080] The length of the measuring rod and the position of the ground point corresponding to the bottom of the measuring rod are kept unchanged, and the position and speed of the top end of the measuring rod are changed. For example, the heading angle is initialized by keeping the bottom end of the measuring rod stationary and pushing the measuring rod back and forth.

[0081] In the conventional initialization, the position and speed information of GNSS is usually matched, (1) the heading initialization is completed based on the position or speed of GNSS. When the advancing direction of the carrier is consistent with the longitudinal axis of the carrier, the angle between the longitudinal axis of the carrier and the geographic north direction is determined by the vector relationship of the position or speed information of GNSS at adjacent time in the navigation coordinate system, and the initial heading angle in the GNSS / INS integrated navigation is obtained; in the initialization process, the walking direction of the measurer needs to be kept consistent with the longitudinal axis of the instrument carrier, the time and accuracy of the initialization are affected by the walking speed of the measurer, and it often takes several seconds or even tens of seconds of walking time to make the accuracy of the heading angle reach a usable level. And this method needs to walk a straight line distance of ten meters or even more to complete the heading initialization, which has requirements for the initialization site, and the accuracy of the heading angle is easily affected by the walking speed of the measurer.

[0082] In the implementation process of the present application, in the RTK fixable area, the bottom end of the measuring rod is kept stationary, the measuring rod is pushed back and forth, the length of the measuring rod and the position of the ground point contacted by the tip of the rod are used as constraint conditions, the position and speed information of the center point of the top end of the measuring rod at multiple epochs are used, and the initial value of the heading angle is obtained through the principle of resection, which avoids the need for the measurer to hold the instrument and walk straight to initialize the operation, the initialization method is simple and flexible, the initialization time is short, and there is no limitation on the initialization site.

[0083] As another embodiment, the method for obtaining the initial heading angle of the tilt measurement of the present application further comprises the following steps after step S1:

[0084] Step S11: Determine whether the heading angle has entered the initialization mode by the first chi-square distribution detection model.

[0085] Optionally, the step of determining whether the heading angle has entered the initialization mode by the first chi-square distribution detection model comprises:

[0086] The sum of squares of velocity residuals in the horizontal direction of the center point of the inertial measurement unit and the sum of squares of velocity residuals in the zenith direction are respectively subjected to chi-square detection, and when both the sum of squares of velocity residuals in the horizontal direction of the center point of the inertial measurement unit and the sum of squares of velocity residuals in the zenith direction pass the chi-square detection, it is determined that the heading angle has entered the initialization mode.

[0087] If the chi-square detection is passed, it is determined that the heading angle has entered the initialization mode; if the chi-square detection is not passed, it is determined that the heading angle has not entered the initialization mode, and the chi-square detection is continued until it is determined that the heading angle has entered the initialization mode.

[0088] In a specific implementation, if the horizontal direction velocity residual sum of squares of the center point of the inertial measurement unit and / or the zenith direction velocity residual sum of squares does not pass the chi-square detection, it is determined that the heading angle has not entered the initialization mode, and the chi-square detection is continued until it is determined that the heading angle has entered the initialization mode.

[0089] Specifically, the first chi-square distribution detection model satisfies the following formula:

[0090]

[0091] wherein, represents the velocity residual sum of squares in the horizontal direction of n ephemeris; represents the velocity residual sum of squares in the zenith direction of n ephemeris; Chi_square represents chi-square distribution; stat is a state detection quantity, 1 represents passing detection, and 0 represents failing detection.

[0092] Specifically, the formula derivation process of the velocity residual sum of squares in the horizontal direction of the center point of the inertial measurement unit and the velocity residual in the zenith direction is as follows:

[0093] The residual corresponding to the model is obtained through formula (6)-(7), and is represented as:

[0094]

[0095] wherein, represents the velocity residual in the horizontal direction, represents the velocity residual in the zenith direction.

[0096] In the solving process, the velocity residual sum of squares of n ephemeris is calculated and chi-square detection is performed to determine whether the heading angle initialization mode is entered, as shown in formula (9):

[0097]

[0098] wherein, represents the velocity residual sum of squares in the horizontal direction of n ephemeris; represents the velocity residual sum of squares in the zenith direction of n ephemeris; Chi_square represents chi-square distribution; stat is a state detection quantity, 1 represents passing detection, and 0 represents failing detection.

[0099] When the horizontal direction and the zenith direction velocity residual square sum pass the chi-square detection, it is judged that the heading angle initialization mode has been entered at this time, and the next step calculation is entered; otherwise, the heading angle initialization state judgment is continued.

[0100] As another embodiment, the method of the present application comprises:

[0101] Step S1: initializing the heading angle;

[0102] Step S2: after the heading angle enters the initialization mode, the initial heading angle is obtained by solving the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit, and the initial heading angle Wherein, ψ is the initial heading angle;

[0103] The position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit satisfies the following formula:

[0104]

[0105] Wherein, The position and velocity of the center point of the inertial measurement unit are respectively P t = [P t e P t n P t u ] T , V t = [V t e V t n V t u ] T The position and velocity of the tip of the measuring rod are respectively P The rod arm value from the center point of the inertial measurement unit to the tip of the measuring rod is L The projection of the gyro data in the b system relative to the n system in the b system is ω The output data of the gyro, The projection of the gyro data in the n system relative to the i system in the b system is ω The conversion matrix from the n system to the b system is C

[0106] Step S3: judging the accuracy of the initial heading angle according to the second chi-square distribution detection model.

[0107] The second chi-square distribution detection model satisfies the following formula:

[0108]

[0109] wherein, Chi_square represents a chi-square distribution; stat is a state detection quantity, 1 represents passing detection, 0 represents failing detection, and n is a natural number. Chi_square represents a chi-square distribution; stat is a state detection quantity, 1 represents passing detection, 0 represents failing detection, and n is a natural number.

[0110] Optionally, the judging the precision of the initial heading angle according to the second chi-square distribution detection model comprises:

[0111] After the heading angle enters the initialization mode, chi-square distribution detection is performed on a residual square sum of n epochs of the center point of the inertial measurement unit in the east direction and a residual square sum of n epochs of the center point of the inertial measurement unit in the north direction, n being a natural number; when the chi-square distribution detection on the residual square sum of n epochs of the center point of the inertial measurement unit in the east direction and the residual square sum of n epochs of the center point of the inertial measurement unit in the north direction both pass the chi-square detection, it is judged that the initial heading angle meets the precision requirement.

[0112] wherein, the calculation method of the residual square sum of n epochs of the center point of the inertial measurement unit in the east direction and the residual square sum of n epochs of the center point of the inertial measurement unit in the north direction is as follows:

[0113] It can be known from the analysis of the formula (12) and the formula (13) that the plane coordinates (P t e ,P t n ) of the ground points obtained by using the least square fitting and the initial heading angle ψ obtained by using the least square fitting have certain errors with respect to the respective true values, and the obtained parameters X are substituted into the formula (10) to obtain the corresponding plane position model error, that is:

[0114]

[0115] wherein, respectively represent the position residuals in the east and north directions; represents a bar arm value under n.

[0116] After it is judged that the heading angle enters the initialization state, the position residual square sum of n epochs is calculated and chi-square detection is performed, and the precision of the initial heading angle is judged by using the fitting degree of the model of the formula (10) to determine whether the precision meets the requirement, that is:

[0117]

[0118] wherein, represents a residual square sum of n epochs of the center point of the inertial measurement unit in the east direction; represents a residual square sum of n epochs of the center point of the inertial measurement unit in the north direction;

[0119] Chi_square represents chi-square distribution; stat is state detection quantity, 1 represents passing detection, and 0 represents failing detection.

[0120] When the position residual square sums in the east direction and the north direction both pass the chi-square detection, it is indicated that the model corresponding to formula (10) has good fitting degree, it is judged that the initial value of the heading angle at this time meets the accuracy requirement, and the next step calculation is entered; otherwise, the solution and accuracy judgment of the initial value of the heading angle are continuously performed.

[0121] In the above implementation process, the chi-square detection is performed on the position residual square sums in the east direction and the north direction, when the position residual square sums in the east direction and the north direction both pass the chi-square detection, it is judged that the initial value of the heading angle at this time meets the accuracy requirement, when the accuracy does not meet the requirement, the solution and accuracy judgment of the initial value of the heading angle are continuously performed, the accuracy of the initial heading angle is improved, and the accuracy judgment method of the heading angle further excludes the experience-based judgment of the heading accuracy, the judgment model is simple, fast and accurate, and the problem that the initial heading angle is determined by assigning a certain weight to the included angle of the matched GNSS / INS trajectories according to certain criteria in the traditional matching method based on the GNSS trajectory and the IMU trajectory is avoided.

[0122] In specific application, the method of the application can be applied as follows:

[0123] Step 1: the rod tip is touched to the ground and kept still for several seconds to calculate the initial pitch angle and roll angle.

[0124] Step 2: the rod tip is kept still, the top end of the measuring rod is shaken, and the roll angle and the pitch angle are updated in real time by using the AHRS attitude algorithm.

[0125] The state equation constructed by the AHRS algorithm is as follows:

[0126]

[0127] Wherein: is a state quantity, q e = [q e1 q e2 q e3 ] T is an error vector corresponding to the imaginary part of the four-element, Δε ω = [Δε ωx Δε ωy Δε ωz ] T is an error vector of the bias estimation; is a state transition matrix, is the projection of the calculated gyro data in the b system relative to the n system in the b system, and I is a unit matrix; is the system noise matrix; W(t) is the system process noise.

[0128] The measurement equation of the AHRS algorithm is constructed as:

[0129] Z(t) = H(t)X(t) + V(t) (17)

[0130] wherein: is a measurement matrix, is an observation error of the accelerometer under the carrier system; V(t) is an observation noise vector.

[0131] After the state equation and the measurement equation of the AHRS algorithm are constructed, the traditional Kalman filtering algorithm is used to update the roll and pitch angles.

[0132] Step 3: the horizontal velocity and the skyward velocity residual values of n epochs are calculated by using formula (8), and it is judged whether the calculated residual values pass the chi-square detection by using formula (9); if the judgment is yes, it is indicated that the heading angle initialization state is entered, otherwise the measuring rod is continued to be shaken.

[0133] Step 4: the initial heading angle ψ is solved by using formula (13), then the solved heading angle and the coordinates of the ground point contacted by the rod tip are substituted into the model of formula (10) to solve the plane position residual values, and finally the fitting degree of the model is judged by using the chi-square distribution detection to judge whether the initial heading angle meets the precision requirement.

[0134] Embodiment Two

[0135] Please refer to Figure 2 , which shows an initial heading angle acquisition device for tilt measurement, comprising:

[0136] An initialization module 10 is used for initializing the heading angle;

[0137] An initial heading angle calculation module 20 is used for solving the initial heading angle by using the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit after the heading angle enters the initialization mode, wherein the initial heading angle wherein ψ is the initial heading angle;

[0138] The position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit satisfies the following formula:

[0139]

[0140] wherein, are respectively the position and the velocity of the center point of the inertial measurement unit; P t = [P t e P tn P t u ] T 、V t =[V t e V t n V t u ] T are the position and velocity corresponding to the rod tip of the measuring rod respectively; is the lever arm value from the center point of the inertial measurement unit to the rod tip of the measuring rod; is the projection of the gyro data in the b system relative to the n system in the b system, is the output data of the gyro, is the projection of the gyro data in the n system relative to the i system in the b system; is the conversion matrix from the n system to the b system.

[0141] Optionally, the initialization module 10 of the present application can also be used to determine whether the heading angle has entered the initialization mode through the first chi-square distribution detection model.

[0142] Optionally, the present application further comprises a precision judgment module: the precision judgment module is used to determine the precision of the initial heading angle according to the second chi-square distribution detection model.

[0143] In the above implementation process, the present application can quickly and accurately obtain the initial heading angle in the tilt measurement by solving the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit, and the precision of the obtained heading angle is not affected by the experience weight value. And the initialization method is to keep the bottom end of the measuring rod stationary and push the measuring rod back and forth for initialization, which is simple and flexible to operate, has a shorter initialization time, has no limitation on the initialization site, and avoids the need for the measurement personnel to hold the instrument and walk straight for initialization operation.

[0144] Embodiment Three:

[0145] Figure 3 is a structural schematic diagram of an electronic device provided by the embodiment of the present application, and in the present application, the electronic device 100 used to implement the tilt measurement initial heading angle acquisition method of the present application can be described by the structural schematic diagram shown in Figure 3 .

[0146] As shown in a structural schematic diagram of an electronic device, Figure 3 the electronic device 100 includes one or more processors 102, one or more storage devices 104, and these components are interconnected through a bus system and / or other forms of connection mechanism (not shown). It should be noted that,Figure 3 The components and structures of the electronic device 100 shown are exemplary only and are not intended to be limiting. The electronic device can have other components and structures not shown, as desired. Figure 3 The components shown can also have other components and structures not shown. Figure 3 The components shown can also have other components and structures not shown.

[0147] The processor 102 can be a central processing unit (CPU) or other form of processing unit that has data processing and / or instruction executing capabilities, and can control other components in the electronic device 100 to perform desired functions.

[0148] The storage 104 can include one or more computer program products that can include various forms of computer-readable storage media, such as volatile and / or non-volatile computer-readable media. For example, the volatile computer-readable media can include random access memory (RAM), cache memory, and / or the like, and the non-volatile computer-readable media can include read only memory (ROM), hard disks, flash memory, and / or the like. The computer-readable storage media can store one or more computer program instructions that, when executed by the processor 102, implement the functions (performed by the processor) described below in the embodiments of the present application and / or other desired functions. The computer-readable storage media can also store various application programs and various data, such as various data used and / or generated by the application programs, and / or the like.

[0149] The application further provides a computer storage medium, which stores a computer program. The method of the application can be stored in the computer storage medium if the method is implemented in the form of a software function unit and sold or used as an independent product. Based on this understanding, the application can implement all or part of the processes in the above-mentioned method embodiments, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer storage medium. When the computer program is executed by a processor, the steps of each method embodiment described above can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, an executable file, or some intermediate form, etc. The computer storage medium can include any entity or device capable of carrying the computer program code, a recording medium, a U disk, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content included in the computer storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in a jurisdiction. For example, according to legislation and patent practice in some jurisdictions, the computer storage medium does not include an electrical carrier signal and a telecommunication signal.

[0150] For those skilled in the art, various corresponding changes and modifications can be made to the technical solutions and concepts described above, and all these changes and modifications should belong to the protection scope of the claims of the application.

Claims

1. A method of acquiring an initial course angle of a tilt measurement, characterized by, Comprise: After the heading angle enters the initialization mode, the ground point in contact with the rod tip of the measuring rod is kept stationary, the top end of the measuring rod is shaken, and the position relationship formula of the corresponding ground point at the bottom of the measuring rod and the center point of the inertial measurement unit is used to solve the unknown parameters by using the data of at least n (≥3) epochs by the least square method to obtain the initial heading angle, and the initial heading angle wherein ψ is the initial heading angle, and the formula involved includes: , , ; wherein, is a conversion matrix from n- to h- system, , is a conversion matrix from h- to b- system; is a conversion matrix from n- to b- system; The position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit satisfies the following formula: wherein, is the position of the IMU center point; is the velocity of the IMU center point; is the position corresponding to the measurement rod tip; is the velocity corresponding to the measurement rod tip; is the rod arm value from the IMU center point to the measurement rod tip; , is the projection of the gyro data in b relative to n in b, is the output data of the gyro, is the projection of the gyro data in n relative to i in b, is the transformation matrix from n to b; i is the inertial coordinate system, b is the carrier coordinate system, and n is the geographic coordinate system.

2. The method of acquiring an initial heading angle of inclination according to claim 1, characterized in that, Before the step of obtaining the initial heading angle by solving the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit, after the heading angle enters the initialization mode, the method further comprises: initializing the heading angle. The step of initializing the heading angle specifically comprises: The length of the measuring rod and the position of the ground point corresponding to the bottom of the measuring rod are kept unchanged, and the position and speed of the top end of the measuring rod are changed.

3. The method of acquiring an initial heading angle of tilt according to claim 2, wherein, Before the step of obtaining the initial heading angle by solving the position relationship formula of the ground point corresponding to the bottom of the measuring rod and the center point of the inertial measurement unit, after the heading angle enters the initialization mode, the method further comprises: The heading angle is chi-square detected by a first chi-square distribution detection model to determine whether the heading angle has entered the initialization mode.

4. The method of acquiring an initial heading angle of tilt according to claim 3, wherein, The first chi-square distribution detection model satisfies the following formula: wherein, represents a residual sum of squares of the velocity of the center point of the inertial measurement unit in the horizontal direction for n epochs; represents a residual sum of squares of the velocity of the center point of the inertial measurement unit in the zenith direction for n epochs; Chi_square represents a chi-square distribution; stat is a state detection quantity, 1 represents passing the detection, 0 represents failing the detection, and n is a natural number.

5. The method of acquiring an initial heading angle of inclination according to claim 4, characterized in that, The horizontal direction velocity residual square of the center point of the inertial measurement unit and the velocity residual in the zenith direction satisfy the following formula: wherein , respectively represent horizontal direction velocity residual and zenith direction velocity residual.

6. The method of acquiring an initial course angle of tilt measurement according to claim 1, wherein Further comprising: According to the second chi-square distribution detection model, the accuracy of the initial heading angle is judged.

7. The method of acquiring an initial heading angle of tilt according to claim 6, wherein, The second chi-square distribution detection model satisfies the following formula: wherein Chi_square represents a residual sum of squares of n epochs in the east direction position; Chi_square represents a residual sum of squares of n epochs in the north direction position; Chi_square represents a chi-square distribution; stat is a state detection quantity, 1 represents passing detection, 0 represents failing detection, and n is a natural number.

8. The method of acquiring an initial heading angle of a tilt measurement according to claim 6, wherein, The step of judging the accuracy of the initial heading angle according to the second chi-square distribution detection model comprises: After the heading angle enters the initialization mode, the residual square sum of the position of the center point of the inertial measurement unit in the east direction and the residual square sum of the position of the center point of the inertial measurement unit in the north direction are respectively chi-square distribution detected for n epochs, n is a natural number; When the residual square sum of the position of the center point of the inertial measurement unit in the east direction and the residual square sum of the position of the center point of the inertial measurement unit in the north direction are both chi-square distribution detected, it is judged that the initial heading angle meets the accuracy requirement.

9. An acquisition device for measuring an initial course angle of inclination, characterized in that, Comprise: An initialization module for initializing the heading angle; An initial heading angle calculation module is configured to keep the ground point contacted by the rod tip of the measuring rod static after the heading angle enters the initialization mode, shake the top end of the measuring rod, and solve the initial heading angle by using the position relationship formula of the corresponding ground point at the bottom of the measuring rod and the center point of the inertial measurement unit, and solving unknown parameters by using data of at least n (≥3) epochs by the least square method. wherein ψ is the initial heading angle, and the formula involved includes: , , ; wherein, is a conversion matrix from n-system to h-system, , is a conversion matrix from h-system to b-system; is a conversion matrix from n-system to b-system; the position relationship formula of the corresponding ground point of the bottom of the measuring rod and the center point of the inertial measurement unit satisfies the following formula: wherein, is the position of the IMU center point; is the velocity of the IMU center point; is the position corresponding to the measuring rod tip; is the velocity corresponding to the measuring rod tip; is the rod arm value from the IMU center point to the measuring rod tip; , is the projection of the gyro data in b-frame relative to n-frame in b-frame, is the output data of the gyro, is the projection of the gyro data in n-frame relative to i-frame in b-frame, is the transformation matrix from n-frame to b-frame; i is the inertial frame, b is the carrier frame, and n is the geographic frame.

10. A computer storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, implements the acquisition method of the initial heading angle of the tilt measurement according to any one of claims 1 to 8.

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