CN110146111B - Initial alignment method of centering rod - Google Patents
Initial alignment method of centering rod Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C25/00—Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass
- G01C25/005—Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass initial alignment, calibration or starting-up of inertial devices
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Abstract
The invention discloses an initial alignment method of a centering rod, which comprises the following steps: 1) Acquiring GNSS and MIMU inertial navigation real-time data, carrying out attitude update, and defining a reference coordinate system required by resolving; 2) Using a geometric constraint method to obtain different observation points according to GNSS, and establishing a measurement equation set; 3) Solving and calculating an azimuth misalignment angle according to the equation set; 4) The MIMU inertial navigation azimuth is corrected by using the azimuth misalignment angle, so that the initial alignment of the centering rod is realized. According to the invention, the high-precision initial alignment of the centering rod can be realized through the positions of the three measuring points, and the method is simple and convenient to operate.
Description
Technical Field
The invention belongs to the technical field of measurement, and particularly relates to an initial alignment method of a centering rod.
Background
In the technical field of engineering measurement such as construction lofting, topographic map mapping, photogrammetry, image control point layout and the like, a real-time dynamic differential method measurement (Real Time Kinematic, RTK) method is widely adopted. RTK is a commonly used satellite navigation (Global Navigation Satellite System, GNSS) measuring method at present, adopts a carrier phase dynamic real-time differential method, can obtain centimeter-level positioning accuracy in real time, and greatly improves the measuring operation efficiency. The GNSS receiver measures the position of the antenna phase center placed at the top end of the centering rod, and the actual mapping needs to be generally performed at the position of the lower tip of the centering rod, so that the traditional operation mode needs to adjust the centering of the leveling bubble on the centering rod, the operation efficiency is low, and the inclination measurement of the centering rod is difficult to realize in the environments of a corner, a pipeline and the like.
The inclination measurement technology is utilized without keeping the centering rod vertical, so that 'stop and pick, pick and walk' is realized, the operation speed can be improved, and meanwhile, the problem that the centering rod cannot reach special points such as corners, cliffs and the like is solved. The inclination measurement technology is mainly divided into two types: firstly, establishing a conversion relation between a centering rod body coordinate system and a geographic coordinate system by means of a micro inertial measurement unit (Miniature Inertial Measurement Unit, MIMU) or a magnetic compass, and automatically compensating inclination errors; and secondly, a shaking inclination measuring method is used for calculating the positions of measuring points by shaking a plurality of points in a centering rod measuring space and carrying out space intersection by taking the length of the centering rod as a constraint condition. Both of the above methods have certain drawbacks. The MIMU is utilized for inclination compensation, and when the inclination angle of the centering rod is larger, the position compensation precision is mainly limited by the azimuth alignment precision of MIMU inertial navigation; and by using a centering rod 'shake-shake' method, each measurement needs to be shaken for many times, and the measurement efficiency is low.
Disclosure of Invention
The invention aims to provide an initial alignment method of a centering rod, which is characterized in that the initial alignment method of the centering rod is realized by utilizing a high-precision azimuth initial alignment method of MIMU inertial navigation, and the GNSS antenna can be aligned by tilting three angular positions in sequence only by keeping the lower tip of the centering rod still, and compared with the method that a handheld GNSS receiver walks for a distance of about 10m, the initial alignment method does not need to move and only needs to rotate in space. In the initial alignment process, the invention does not need to move in a large range and occupies small space.
In order to achieve the technical effects, the present invention is realized by the following technical means.
A method of initial alignment of a centering rod comprising the steps of:
1) Acquiring GNSS and MIMU inertial navigation real-time data, carrying out attitude update, and defining a reference coordinate system required by resolving;
2) Using a geometric constraint method to obtain different observation points according to GNSS, and establishing a measurement equation set;
the step 2) is to use a geometric constraint method to obtain different observation points according to GNSS, and to establish a measurement equation set, specifically: the bottom of the centering rod is kept fixed, and the centering rod is rotated to be positioned at three points which are respectively marked as P 1 n 、Andtaking any two points, respectively marked as P i n And->They are taken as difference->Is available in the form of
In the formula (4) of the present invention,projection of the lever arm under a navigation coordinate system; but->Then the projection of the lever arm representing the other point under the navigational coordinate system; lever arm error is +.> An ideal attitude array for MIMU inertial navigation output; nominal lever arm vector +.> For inertial navigation to solve at position point P i n An output gesture array; phi (phi) i ＝[φ i，E φ i，N φ i，U ] T Inertial navigation at position point P for MIMU i n Is a misalignment angle error of (a);
simply expressed as formula (5):
wherein,,to construct a measurement, a difference between two tilt measurements representing the deviation of the GNSS output from the MIMU inertial navigation output; />The difference between two measurements of the inertial navigation attitude array;
MIMU inertial navigation is subjected to accelerometer leveling, and then a horizontal misalignment angle phi is usually adopted i，E And phi i，N Are compared with the azimuth misalignment angle phi i，U Small if ignore phi i，E And phi i，N Then formula (5) may be approximated as
Or alternatively
Wherein, recordφ i U ＝[0 0 φ i，U ] T />
Will center three points P in the lever rotation 1 n 、And->Respectively substituting into the formula (7), constructing two measurement equations and forming an equation set, wherein the two measurement equations are as follows:
is simply described as
Z＝HX (9)；
3) Solving and calculating an azimuth misalignment angle according to the equation set;
4) And correcting the MIMU inertial navigation azimuth by using the azimuth misalignment angle to realize the initial alignment of the centering rod.
As a further development of the invention, the reference coordinate system required for the definition of the solution in step 1) is in particular:
b-a carrier coordinate system, which represents a three-axis orthogonal coordinate system of a strapdown MIMU inertial navigation system, wherein an X axis, a y axis and a z axis respectively point to the right-front-top of the carrier;
the n-navigation coordinate system represents a geographic coordinate system of the position of the carrier, and three axes of the n-navigation coordinate system point to the local east direction, the north direction and the sky direction respectively;
p-lower point P of centering rod 0 Three-dimensional coordinates in contact with the ground;
the GNSS antenna is arranged at the top of the centering rod, and the contact point between the bottom of the centering rod and the ground isObtaining the phase center point P of the GNSS receiving antenna at the upper end of the centering rod i Is>The coordinate conversion formula is:
wherein,,an ideal attitude array for MIMU inertial navigation output; l (L) b Is an ideal lever arm vector for the center of the GNSS antenna relative to the bottom of the centering lever.
As a further improvement of the invention, the method also comprises the establishment of a three-dimensional coordinate error model, which is specifically as follows: adding the MIMU inertial navigation attitude array error and the lever arm vector error into the formula (1) to obtain the formula (2), namely:
wherein the method comprises the steps of，For the inertial navigation solution output of the attitude matrix, the nominal lever arm vector +.>MIMU inertial navigation misalignment angle error phi i ＝[φ i，E φ i，N φ i，U ] T Lever arm error is->
As a further improvement of the present invention, the processing of the above formula (2) is further included, specifically, the formula (2) is obtained by omitting the second order small amount processing to obtain the formula (3), namely:
wherein,,is the projection of the lever arm in the navigation coordinate system.
In order to linearize and facilitate processing, in the technical scheme, the second-order small-amount processing is omitted, so that the whole operation is more convenient to calculate.
As a further improvement of the present invention, the step 2) uses a geometric constraint method to obtain different observation points according to GNSS, and establishes a measurement equation set, specifically: the bottom of the centering rod is kept fixed, and the centering rod is rotated to be positioned at three points which are respectively marked as P 1 n 、And->Taking any two points, respectively marked as P i n And->They are taken as difference->Obtainable with reference to (3)
Simply expressed as formula (5):
wherein,,to construct a measurement, a difference between two tilt measurements representing the deviation of the GNSS output from the MIMU inertial navigation output; />The difference between two measurements of the inertial navigation attitude array;
MIMU inertial navigation is subjected to accelerometer leveling, and then a horizontal misalignment angle phi is usually adopted i，E And phi i，N Are compared with the azimuth misalignment angle phi i，U Small if ignore phi i，E And phi i，N Then formula (5) may be approximated as
Or alternatively
Wherein, recordφ i U ＝[0 0 φ i，U ] T />
Will center three points P in the lever rotation 1 n 、And->Respectively substituting into the formula (7), constructing two measurement equations and forming an equation set, wherein the two measurement equations are as follows:
is simply described as
Z＝HX (9)。
By establishing the equation set, the operation becomes simple and the calculation is convenient.
As a further improvement of the present invention, the step 3) solves and calculates the azimuth misalignment angle according to the equation set, specifically:
through three points P 1 n 、And->The unknown X in equation (9) can be found, i.e
X＝H -1 Z (10)
Calculating three different azimuth misalignment angles phi i，U 。
As a further improvement of the present invention, the step 4) corrects the MIMU inertial navigation bearing by using the bearing misalignment angle, and the initial alignment of the centering rod is specifically:
through three different azimuth misalignment angles phi i，U Angle of azimuth misalignment phi of the third time in 3，U Correcting posture matrixAn initial alignment of the centering rod is achieved.
As a further development of the invention, in step 2), the centering rod is rotated in the range of 10 ° to 45 °.
In actual operation, the rotation angle is generally not more than 60 degrees, mainly the larger the rotation angle degree is, the larger the satellite receiving measurement error of the GNSS antenna is, which is not beneficial to calculation; the smaller the degree of rotation angle, the less the geometric constraint structure is, and the calculation error is large.
The beneficial effects of the invention are as follows:
RTK measurement operation is carried out by using MIMU inertial navigation assisted GNSS, errors generated when the centering rod is inclined can be effectively compensated by correctly solving the azimuth angle of the inertial navigation, and point position horizontal coordinates and elevations meeting precision are obtained. The invention provides an algorithm for solving an initial azimuth angle by a three-point method, and after the azimuth initialization algorithm is applied, an actual measurement result shows that even if the inclination angle of a centering rod reaches approximately 40 degrees in the test process, the horizontal positioning precision of RTK measurement is better than 1.25cm.
In the whole test process of the invention, the change of the inclination angle alpha of the centering rod is between 10 and 40 degrees, and P is calculated under 20 different inclination angles 0 The three-dimensional positioning error of the point is measured after the inclination is stable, and the inclination angle cannot be measured in the movement process. In the statistics of positioning errors, horizontal positioning errorsAnd->Are all smaller than 1.25cm, while the height positioning error is +.>Less than 0.56cm.
Drawings
FIG. 1 is a schematic view showing the placement structure of a centering rod in embodiment 1 provided by the present invention;
FIG. 2 shows the phi in example 1 provided by the present invention U Schematic of (2);
fig. 3 is a graph showing the change of the inclination angle of the centering rod according to the present invention.
Detailed Description
The invention is further described in connection with the following embodiments in order to make the technical means, the creation features, the achievement of the purpose and the effect of the invention easy to understand.
The invention provides an initial alignment method of a centering rod, which comprises the following steps:
1) Acquiring GNSS and MIMU inertial navigation real-time data, carrying out attitude update, and defining a reference coordinate system required by resolving;
2) Using a geometric constraint method to obtain different observation points according to GNSS, and establishing a measurement equation set;
3) Solving and calculating an azimuth misalignment angle according to the equation set;
4) And correcting the MIMU inertial navigation azimuth by using the azimuth misalignment angle to realize the initial alignment of the centering rod.
As a further development of the invention, the reference coordinate system required for the definition of the solution in step 1) is in particular:
b-a carrier coordinate system, which represents a three-axis orthogonal coordinate system of a strapdown MIMU inertial navigation system, wherein an X axis, a y axis and a z axis respectively point to the right-front-top of the carrier;
the n-navigation coordinate system represents a geographic coordinate system of the position of the carrier, and three axes of the n-navigation coordinate system point to the local east direction, the north direction and the sky direction respectively;
p-lower point P of centering rod 0 Three-dimensional coordinates in contact with the ground;
the GNSS is arranged at the top of the centering rod, and the contact point between the bottom of the centering rod and the ground isObtaining the phase center point P of the GNSS receiving antenna at the upper end of the centering rod i Is>The coordinate conversion formula is:
wherein,,an ideal attitude array for MIMU inertial navigation output; l (L) b An ideal lever arm vector for the GNSS receiver antenna center relative to the bottom of the centering lever.
Further, the method also comprises the establishment of a three-dimensional coordinate error model, specifically comprising the following steps: adding the MIMU inertial navigation attitude array error and the lever arm vector error into the formula (1) to obtain the formula (2), namely:
wherein,,for the inertial navigation solution output of the attitude matrix, the nominal lever arm vector +.>MIMU inertial navigation misalignment angle error phi i ＝[φ i，E φ i，N φ i，U ] T Lever arm error is->
As a further improvement of the present invention, the processing of the above formula (2) is further included, specifically, the formula (2) is obtained by omitting the second order small amount processing to obtain the formula (3), namely:
wherein,,is the projection of the lever arm in the navigation coordinate system.
In order to linearize and facilitate processing, in the technical scheme, the whole operation is more convenient to calculate by adopting second-order small-quantity processing.
As a further improvement of the present invention, the step 2) uses a geometric constraint method to obtain different observation points according to GNSS, and establishes a measurement equation set, specifically: the bottom of the centering rod is kept fixed, and the centering rod is rotated to be positioned at three points which are respectively marked as P 1 n 、And->Taking any two points, respectively marked as +.>And->They are taken as difference->Obtainable with reference to (3)
Simply expressed as formula (5):
wherein,,to construct a measurement, a difference between two tilt measurements representing the deviation of the GNSS output from the MIMU inertial navigation output; />The difference between two measurements of the inertial navigation attitude array;
MIMU inertial navigation is subjected to accelerometer leveling, and then a horizontal misalignment angle phi is usually adopted i，E And phi i，N Are compared with the azimuth misalignment angle phi i，U Small if ignore phi i，E And phi i，N Then formula (5) may be approximated as
Or alternatively
Wherein, recordφ i U ＝[0 0 φ i，U ] T />
Will center three points P in the lever rotation 1 n 、And->Respectively substituting into the formula (7), constructing two measurement equations and forming an equation set, wherein the two measurement equations are as follows:
is simply described as
Z＝HX (9)。
By establishing the equation set, the operation becomes simple and the calculation is convenient.
As a further improvement of the present invention, the step 3) solves and calculates the azimuth misalignment angle according to the equation set, specifically:
through three points P 1 n 、And->The unknown X in equation (9) can be found, i.e
X＝H -1 Z (10)
Calculating three different azimuth misalignment angles phi i，U 。
As a further development of the invention, in step 2), the centering rod is rotated in the range of 10 ° to 45 °.
When the rotation angle is smaller than 10 degrees, the geometric constraint structure is not good, and the calculation error is large; when the rotation angle is larger than 45 degrees, the satellite receiving measurement error of the GNSS antenna is larger, which is not beneficial to calculation.
The invention mainly adopts a calculation method of inertial navigation plus geometric constraint of satellite measurement points, namely, the azimuth angle of inertial navigation is quickly initialized, MIMU is utilized for tilt compensation, when the tilt angle of the centering rod is larger, the position compensation precision is mainly limited by the azimuth alignment precision of MIMU inertial navigation, the invention mainly discusses the high-precision azimuth initial alignment method of MIMU inertial navigation, and the method only needs to keep the lower tip of the centering rod still, and the GNSS antenna is sequentially tilted for three angular positions, thereby realizing alignment.
Example 1
Referring to fig. 1 to 3, the initial alignment method in this embodiment is divided into two major parts.
First part, high precision azimuth initial alignment algorithm
As shown in fig. 1, the MIMU is fixedly attached to the top end of the centering rod together with the GNSS receiver. The MIMU body coordinate system is abbreviated as b-system. The lower point of the centering rod is marked as P 0 The GNSS antenna phase center is denoted as P i (i＝1，2，3，…)，The projection on line b is constant and is denoted as lever arm vector +.>The GNSS output is generally longitude and latitude high geographic coordinates, which are easily converted into local station rectangular coordinates, such as P 1 The point is the rectangular coordinates (unit meter) of "east-north-day" with the origin, and the coordinate system is abbreviated as n-system hereinafter.
When the centering rod is placed on the ground at a certain inclined position P i At the time, it is assumed that the lower point P of the pole is centered 0 Three-dimensional coordinates of contact with the groundAssuming no error, the phase center point P of the GPS receiving antenna at the upper end of the centering rod i Is given by the ideal three-dimensional coordinates ofThe ideal attitude array of inertial navigation output is +.>According to the geometric relationship, the following coordinate conversion formula is established
In practical application, the attitude matrix of the inertial navigation calculation output is error and is directly output through MIMU inertial navigation and recorded asThe lever arm nominal value also has an error, noted +.>Equation (1) becomes after the process of establishing the three-dimensional coordinate error model
Wherein phi is i ＝[φ i，E φ i，N φ i，U ] T In order to be an inertial navigation misalignment angle error,is a lever arm error.
Expanding equation (2) and omitting the second order small amount about the error, it is possible to obtain
Wherein,,is the projection of the nominal lever arm under the inertial navigation system.
Keeping the contact point between the lower tip of the centering rod and the ground stationary, and performing two tilt measurements, respectively designated as P i n Andthey are taken as difference->Obtainable with reference to (3)
Is simply described as
Wherein,,to construct a measurement, a difference between two tilt measurements representing the deviation of the GPS output from the inertial navigation output; />Is the difference between two measurements of the inertial navigation attitude array.
After inertial navigation is leveled by an accelerometer, the inertial navigation is generally horizontally misaligned by an angle phi i，E And phi i，N Are compared with the azimuth misalignment angle phi i，U Much smaller if phi is ignored i，E And phi i，N Then formula (5) may be approximated as
Or alternatively
Wherein, recordφ i U ＝[0 0 φ i，U ] T />
Equation (7) contains five unknown error parameters that cannot be solved by a measurement equation. If three measurements are made, they are respectively designated as P 1 n 、And->Then two measurement equations can be constructed and a set of equations can be constructed according to equation (7), as follows
Is simply described as
Z＝HX (9)
When the lower tip of the centering rod is fixed and inclines by a certain fixed angle (for example, the included angle between the centering rod and the plumb line is 30 degrees), the space motion track forms a conical surface, three measuring points are uniformly selected on the conical surface, the measuring matrix H formed by the three measuring points is reversible, and then the unknown parameter X can be directly obtained by the formula (9), namely
X＝H -1 Z (10)
If the azimuth is misaligned by an angle phi i，U If the angle is not a small angle, the correct azimuth angle can be obtained through a method of repeated iterative correction, and azimuth initialization under a large azimuth misalignment angle is realized.
In particular, assuming that the z-axis of the MIMU is mounted parallel to the centering rod, then the centering rod has a lever arm error only in the telescoping direction, i.eThen assume that the measurement time is relatively short, i.e. the azimuth misalignment angle phi caused by gyro drift i，U The change is not large and can be regarded as a constant value phi U . The measurement equation can be obtained by two measurements
Wherein,,representation matrix->Is the 3 rd column vector. The least squares solution of formula (11) is
Further, if lever arm vector l b Precisely known, i.e. δl b =0, then equation (11) is reduced to
Least squares solution of azimuth misalignment angle
Such as a passwordI.e. the calculated nominal lever arm vector for the 1 position and the GNSS measurement are both set to zero, equation (13) can also be written as
Wherein,,φ U ＝[0 0 φ U ] T . The geometric meaning of formula (15) is: two horizontal vectors->And->The included angle between them is phi U See FIG. 2, at phi U This is true also for large angles.
Second partial error analysis
2.1 positioning error analysis
From GPS measurements P i n Calculated value of inertial lever armSolving the lower tip position of the centering rod>The actual method is that
However, according to formula (3), there are theoretically
Comparing formula (16) with formula (17) shows thatThe measurement error of (2) is
If only the azimuthal misalignment angle effects are considered,representing the projection of the lever arm on the horizontal plane +.>And phi is equal to i U Cross product of size +.>Wherein alpha is the included angle of the centering rod and the plumb line; />Is the magnitude of the lever arm error modulo +.>So the positioning error can be estimated as
Equation (19) shows that both the azimuth alignment error and the nominal length error of the centering rod can affect the measurement calculation of the lower point, the centering rod arm vector should be effectively accurate in practical application, the millimeter precision can be generally achieved, and the error can be ignored for centimeter mapping requirements. Therefore, azimuth alignment accuracy is very important in the MIMU inertial navigation tilt compensation scheme.
2.2 Azimuth alignment error analysis
Regardless of lever arm error, equation (14) is an equation for calculating the azimuth misalignment angle from the two tilt positions:
note that:comprises two GNSS positioning measurements, so that the GNSS positioning noise error directly affects the alignment of the position, according to the least squares theory +.>The variance of (2) is
Wherein 2σ 2 To measureError, sigma of 2 East or north errors (variances) for GNSS single positioning;called horizontal dilution of precision factor (Horizontal Dilution Of Preci)sion, HDOP), due toWhen->And->When the plumb line is symmetrical and the inclination angle is larger, the HDOP value is smaller, and the azimuth alignment precision is higher. Obviously, when +.>And->Symmetrical about the plumb line and with an inclination angle α, there is +.>At this time, the azimuth alignment variance is
For example, when σ=1 cm, l=2m, and α=40°, the standard deviation of the calculated azimuth alignment is
Third part of test verification
The test system mainly comprises a carrier phase difference GNSS, a MIMU inertial navigation system, a centering rod, a data acquisition notebook and a storage battery. The GNSS base station is fixed on the ground, and the GNSS mobile station antenna and the MIMU inertial navigation are fixedly arranged at the top end of the centering rod; the acquisition frequency of a GNSS mobile station receiver is 5Hz, and the horizontal positioning static precision is 0.7cm (1 sigma); MIMU data acquisition frequency is 100Hz, zero bias stability of the gyroscope is about 30 degrees/h, and zero bias repeatability of the accelerometer is about 2mg; the center of the phase of the GNSS antenna at the top end of the centering rod is 1.897m away from the lower tip; the notebook synchronously collects GNSS positioning and MIMU inertial sensor data, performs post-hoc analysis, and comprises the following steps:
(1) Leveling by MIMU output using mahonyl algorithm, see fig. 3, in three tilt positions P of the centering rod 1 、P 2 And P 3 Position determination posture arrayAnd->The azimuth angles are all set to 0;
(2) Iteratively solving and correcting according to the formula (10) to obtain an initial posture matrix
(3) 15-dimensional inertial navigation/GNSS integrated navigation model is built by taking position error as measurement, and the model is started from inclined position P 3 Starting to perform combined Kalman filtering;
(4) Maintaining the lower tip of the centering rod motionless, tilting the centering rod in different directions by different angles, performing GNSS positioning measurement each time the tilting is stable, and calculating the position P of the lower tip by using the method (16) 0 Is used for the positioning of the mobile terminal.
Throughout the test, the change in the inclination angle of the centering rod is shown by the solid line in FIG. 3, the inclination angle alpha is changed between 0 and 40 DEG, and the discrete points from 170s to 450s are calculated as P under 20 different inclination angles 0 And (3) three-dimensional positioning errors of the points. The positioning error statistics are listed in table 1, and the results show that: horizontal positioning errorAnd->Are all smaller than 1.25cm, while the height positioning error is +.>0.56cm.
TABLE 1 statistics of positioning errors (cm)
As can be seen from Table 1, the horizontal positioning errorAnd->Are all smaller than 1.25cm, and have high positioning errorsLess than 0.56cm.
In the invention, the MIMU inertial navigation assisted GNSS is utilized to carry out RTK measurement operation, so that errors generated when the centering rod tilts can be effectively compensated, and point coordinates and elevations meeting the precision are obtained, but the condition is that the MIMU inertial navigation is required to be correctly initialized, and the posture precision, particularly the azimuth precision, of the MIMU inertial navigation determines the effect of compensating the tilting errors of the centering rod.
The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (7)
1. A method of initial alignment of a centering rod, comprising the steps of:
1) Acquiring GNSS and MIMU inertial navigation real-time data, carrying out attitude update, and defining a reference coordinate system required by resolving;
2) Using a geometric constraint method to obtain different observation points according to GNSS, and establishing a measurement equation set;
the step 2) is to use a geometric constraint method to obtain different observation points according to GNSS, and to establish a measurement equation set, specifically: the bottom of the centering rod is kept fixed, and the centering rod is rotated to be positioned at three points which are respectively marked as P 1 n 、And->Taking any two points, respectively marked as P i n And->They are taken as difference->Is available in the form of
In the formula (4) of the present invention,projection of the lever arm under a navigation coordinate system; but->Then the projection of the lever arm representing the other point under the navigational coordinate system; lever arm error is +.>An ideal attitude array for MIMU inertial navigation output; nominal lever arm vector +.>For inertial navigation to solve at position point P i n An output gesture array; phi (phi) i ＝[φ i，E φ i，N φ i，U ] T Inertial navigation at position point P for MIMU i n Is a misalignment angle error of (a);
simply expressed as formula (5):
wherein,,to construct a measurement, a difference between two tilt measurements representing the deviation of the GNSS output from the MIMU inertial navigation output; />The difference between two measurements of the inertial navigation attitude array;
MIMU inertial navigation is subjected to accelerometer leveling, and then a horizontal misalignment angle phi is usually adopted i,E And phi i,N Are compared with the azimuth misalignment angle phi i,U Small if ignore phi i,E And phi i,N Then formula (5) may be approximated as
Or alternatively
Wherein, recordφ i U ＝[0 0 φ i，U ] T ，/>
Will center three points P in the lever rotation 1 n 、And->Respectively substituting into the formula (7), constructing two measurement equations and forming an equation set, wherein the two measurement equations are as follows:
is simply described as
Z＝HX (9)；
3) Solving and calculating an azimuth misalignment angle according to the equation set;
4) And correcting the MIMU inertial navigation azimuth by using the azimuth misalignment angle to realize the initial alignment of the centering rod.
2. The method of initial alignment of a centering rod according to claim 1, wherein the reference coordinate system required for the resolution defined in step 1) is specifically:
b-a carrier coordinate system, which represents a three-axis orthogonal coordinate system of the strapdown MIMU inertial navigation system, wherein an x axis, a y axis and a z axis respectively point to the right-front-top of the carrier;
the n-navigation coordinate system represents a geographic coordinate system of the position of the carrier, and three axes of the n-navigation coordinate system point to the local east direction, the north direction and the sky direction respectively;
p-lower point P of centering rod 0 Three-dimensional coordinates in contact with the ground;
the GNSS is arranged at the top of the centering rod, and the contact point between the bottom of the centering rod and the ground isObtaining the phase center point P of the GNSS receiving antenna at the upper end of the centering rod i Is>The coordinate conversion formula is:
wherein,,an ideal attitude array for MIMU inertial navigation output; l (L) b Is an ideal lever arm vector for the center of the GNSS antenna relative to the bottom of the centering lever.
3. The method for initial alignment of a centering rod according to claim 2, further comprising the establishment of a three-dimensional coordinate error model, in particular: adding the MIMU inertial navigation attitude array error and the lever arm vector error into the formula (1) to obtain the formula (2), namely:
wherein,,for the inertial navigation solution output of the attitude matrix, the nominal lever arm vector +.>MIMU inertial navigation misalignment angle error phi i ＝[φ i，E φ i，N φ i，U ] T Lever arm error is->
4. A method of aligning a centering rod according to claim 3, further comprising the processing of the above formula (2), specifically, the processing of the formula (2) by omitting the second order small amount to obtain the formula (3), namely:
wherein,,is the projection of the lever arm in the navigation coordinate system.
5. The method of claim 1, wherein the step 3) is to solve the azimuth misalignment angle according to the equation set, and the method is to:
through three points P 1 n 、And->The unknown X in equation (9) can be found, i.e
X＝H -1 Z (10)
Calculating three different azimuth misalignment angles phi i,U 。
6. The method of claim 5, wherein said step 4) uses the azimuth misalignment angle to correct the MIMU inertial navigation azimuth, and the initial alignment of the centering rod is achieved by:
through three different azimuth misalignment angles phi i,U Angle of azimuth misalignment phi of the third time in 3,U Correcting posture matrixAn initial alignment of the centering rod is achieved.
7. A method of initial alignment of a centering rod as claimed in claim 1, wherein in step 2) the centering rod is rotated in the range of 10 ° -45 °.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8487812B1 (en) * | 2011-06-02 | 2013-07-16 | Rockwell Collins, Inc. | Method for self-aligning a beamforming sensor to simplify vehicle installation |
| CN109269471A (en) * | 2018-11-09 | 2019-01-25 | 上海华测导航技术股份有限公司 | A kind of novel GNSS receiver inclinometric system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US8639416B2 (en) * | 2003-03-20 | 2014-01-28 | Agjunction Llc | GNSS guidance and machine control |
| CN103557871B (en) * | 2013-10-22 | 2016-06-15 | 北京航空航天大学 | A kind of lighter-than-air flight aerial Initial Alignment Method of device inertial navigation |
| CN103557876B (en) * | 2013-11-15 | 2016-01-20 | 山东理工大学 | A kind of inertial navigation Initial Alignment Method for antenna tracking stable platform |
| CN104459728B (en) * | 2014-12-17 | 2017-03-29 | 广州吉欧电子科技有限公司 | A kind of magnetic declination calibration steps positioned based on GNSS |
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| CN106643806B (en) * | 2016-12-30 | 2019-09-06 | 深圳友铂科技有限公司 | A kind of inertial navigation system alignment precision appraisal procedure |
| CN108955670B (en) * | 2017-05-25 | 2021-02-09 | 百度在线网络技术（北京）有限公司 | Information acquisition method and device |
| CN109556632B (en) * | 2018-11-26 | 2021-01-29 | 北方工业大学 | INS/GNSS/polarization/geomagnetic integrated navigation alignment method based on Kalman filtering |
| CN109696153B (en) * | 2018-12-25 | 2021-09-14 | 广州市中海达测绘仪器有限公司 | RTK tilt measurement accuracy detection method and system |
-
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- 2019-06-03 CN CN201910475763.4A patent/CN110146111B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8487812B1 (en) * | 2011-06-02 | 2013-07-16 | Rockwell Collins, Inc. | Method for self-aligning a beamforming sensor to simplify vehicle installation |
| CN109269471A (en) * | 2018-11-09 | 2019-01-25 | 上海华测导航技术股份有限公司 | A kind of novel GNSS receiver inclinometric system and method |
Non-Patent Citations (1)
| Title |
|---|
| 捷联惯导系统静基座的高精度初始对准方法;王雪瑞;周岩;;洛阳理工学院学报(自然科学版);27(01);全文 * |
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