阅读说明：本技术 一种罗经对准/逆向惯性姿态更新组合的大失准角快速对准方法 (Large misalignment angle fast alignment method of compass alignment/reverse inertial attitude update combination ) 是由 张延顺 孔玲 孙雪 于 2021-08-05 设计创作，主要内容包括：一种罗经对准/逆向惯性姿态更新组合的大失准角快速对准方法,包含以下几个步骤：(1)根据精度要求和载体环境,确定重复数据的时间长度和初始时刻的航向姿态角。(2)在数据长度内运行罗经对准,得到数据结束时刻的航向姿态角。相比于初始时刻,数据结束时刻的航向和姿态角误差有所减小。(3)利用时间长度内逆向的惯性传感器数据,从结束时刻航向姿态角逆向回推,得到与初始时刻数据对应的航向与姿态角。(4)以回推获得的姿态角为初始值,重复利用时间长度内的惯性传感器数据,第2次运行罗经对准算法,得到误差更小的航向与姿态角。(5)重复步骤(3)、(4),直到满足罗经对准结束条件。(A big misalignment angle fast alignment method of compass alignment/reverse inertia attitude update combination comprises the following steps: (1) and determining the time length of the repeated data and the course attitude angle at the initial moment according to the precision requirement and the carrier environment. (2) And running compass alignment in the data length to obtain the course attitude angle of the data ending moment. The heading and attitude angle errors at the end of the data are reduced compared to the initial time. (3) And reversely extrapolating the course attitude angle from the ending moment by utilizing the reversed inertial sensor data in the time length to obtain the course and the attitude angle corresponding to the initial moment data. (4) And (4) taking the attitude angle obtained by the back-pushing as an initial value, repeatedly utilizing inertial sensor data in a time length, and operating the compass alignment algorithm for the 2 nd time to obtain the course and the attitude angle with smaller errors. (5) And (5) repeating the steps (3) and (4) until the compass alignment end condition is met.)

1. A big misalignment angle fast alignment method of compass alignment/reverse inertia attitude update combination is characterized by comprising the following steps:

(1) and determining the time length of the repeated data and the course attitude angle at the initial moment according to the precision requirement and the carrier environment.

(2) And running compass alignment in the data length to obtain the course attitude angle of the data ending moment. The heading and attitude angle errors at the end of the data are reduced compared to the initial time.

(3) And reversely extrapolating the course attitude angle from the ending moment by utilizing the reversed inertial sensor data in the time length to obtain the course and the attitude angle corresponding to the initial moment data. Because the updating error of the inertial attitude is smaller in a short period, the attitude after a period of time convergence can be transmitted to the initial time to generate a new initial value of the course attitude angle. Compared with the initial course attitude angle obtained without reverse operation, the initial attitude angle obtained by back-pushing is closer to a true value, and the precision is higher.

(4) And (4) taking the attitude angle obtained by the back-pushing as an initial value, repeatedly utilizing inertial sensor data in a time length, and operating the compass alignment algorithm for the 2 nd time to obtain the course and the attitude angle with smaller errors.

(5) And (5) repeating the steps (3) and (4) for multiple times until the compass alignment end condition is met.

2. The method of claim 1 for fast alignment with large misalignment angle of compass alignment/inverse inertial attitude update combination, wherein: according to the characteristic that the compass alignment can be aligned under a moving base and the inertial attitude update has high precision in a short period, the compass alignment and the inertial attitude update are comprehensively applied to align a large misalignment angle, error convergence is realized by using an algorithm, and the converged alignment precision is transmitted to the data initial time by using reverse inertial attitude update. And a foundation is laid for the quick convergence of the next alignment error.

3. The method of claim 1 for fast alignment with large misalignment angle of compass alignment/inverse inertial attitude update combination, wherein: the method of the invention can greatly shorten the alignment time while meeting the alignment precision. The method repeatedly applies data with a period of time, and from the first updating of the reverse inertial attitude, the alignment operation is not required to be performed after waiting for the next sampling moment, but is continuous operation, so that the method consumes less time, and can obtain the alignment accuracy which can be achieved only by the data with the time length of several times. That is to say, under the condition of achieving the same alignment precision, the method needs less time consumption and improves the alignment speed.

4. The method of claim 1 for fast alignment with large misalignment angle of compass alignment/inverse inertial attitude update combination, wherein: and setting a precision threshold of compass alignment in advance according to application requirements, taking the difference between the results of the latest two compass alignments, ending the circulation if the threshold is reached, taking the result of the last compass alignment as the alignment result, and continuing the circulation if the threshold is not reached.

Technical Field

The invention relates to a large misalignment angle fast alignment method of compass alignment/reverse inertial attitude update combination, which combines the characteristics of course convergence of a compass system along with time and high updating precision of short-term inertial attitude, repeatedly applies acquired inertial sensor data and repeatedly carries out forward compass alignment and reverse inertial attitude update for many times. The method can realize compass alignment which can be achieved only in a long time in a short time, and improve the alignment speed.

Background

With the increase of the demand of human beings for marine resources, marine exploration and development become an important task for the vigorous development of countries in the world. Besides the detection and operation equipment, the navigation and positioning of the device are also an essential link in ocean detection and development. The performance of navigation has a significant impact on the effectiveness of ocean engineering, and therefore researchers have conducted research on navigation and positioning of underwater vehicles during near-shore terrain mapping, target searching, and other tasks. Among them, alignment is a technical bottleneck that restricts the navigation accuracy. Particularly, under the emergency water entering condition, the precise alignment is not performed for enough time, so that the initial misalignment angle is large, and a large positioning error occurs in the navigation process, and therefore how to realize the rapid alignment of the large misalignment angle of the underwater vehicle becomes a problem to be solved urgently.

The strapdown compass is used as a dynamic alignment method and widely applied to navigation of underwater vehicles. The alignment time is one of the key performance parameters of the strapdown compass, and the alignment time and the alignment precision of the strapdown compass cannot be obtained at the same time in general. Compass alignment is divided into two stages, namely horizontal alignment and azimuth alignment, wherein the horizontal alignment is relatively fast and high in precision, and the azimuth alignment is a technical bottleneck limiting compass alignment performance. The azimuth error of the traditional compass alignment method is convergent, but as the initial misalignment angle increases, a longer convergence time is required to achieve the same alignment accuracy. In the offshore sub-carrier, emergency entry situation, there is not enough time and a relatively steady state for initial alignment. The initial misalignment angle upon emergency entry into water is also large, which presents a severe challenge to the implementation of fast, high precision alignment.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the fast compass alignment method is researched by combining the characteristics of convergence of course of compass algorithm along with time and high updating precision of short-term inertial attitude, repeatedly utilizing inertial measurement data in a short time and updating and combining the compass and the inertial attitude. A new solution is provided for the application of fast alignment methods at large misalignment angles.

The technical solution of the invention is as follows: a big misalignment angle fast alignment method of compass alignment/reverse inertia attitude update combination is characterized by comprising the following steps:

(1) and determining the time length of the repeated data and the course attitude angle at the initial moment according to the precision requirement and the carrier environment.

(2) And running compass alignment in the data length to obtain the course attitude angle of the data ending moment. The heading and attitude angle errors at the end of the data are reduced compared to the initial time.

(3) And reversely extrapolating the course attitude angle from the ending moment by utilizing the reversed inertial sensor data in the time length to obtain the course and the attitude angle corresponding to the initial moment data. Because the updating error of the inertial attitude is smaller in a short period, the attitude after a period of time convergence can be transmitted to the initial time to generate a new initial value of the course attitude angle. Compared with the initial course attitude angle obtained without reverse operation, the initial attitude angle obtained by back-pushing is closer to a true value, and the precision is higher.

(4) And (4) taking the attitude angle obtained by the back-pushing as an initial value, repeatedly utilizing inertial sensor data in a time length, and operating the compass alignment algorithm for the 2 nd time to obtain the course and the attitude angle with smaller errors.

(5) And (5) repeating the steps (3) and (4) for multiple times until the compass alignment end condition is met.

The principle of the invention is as follows: first, using inertial sensor data over a period of time T toPerforming compass alignment for the initial value to obtainWhile the compass calculation is carried out, the data (comprising gyroscope and accelerometer data) of the section is stored; then is provided withStarting as an initial value, updating the inertial attitude in a reverse direction by applying data of a gyroscope and an accelerometer to obtain an initial attitude and a course which are closer to the actual initial attitudeAnd repeating the calculation for multiple times until the requirements of application precision and time are met.

Compared with the prior art, the invention has the advantages that:

(1) according to the characteristic that the compass alignment can be aligned under a moving base and the inertial attitude update has high precision in a short period, the compass alignment and the inertial attitude update are comprehensively applied to align a large misalignment angle, error convergence is realized by using an algorithm, and the converged alignment precision is transmitted to the data initial time by using reverse inertial attitude update. And a foundation is laid for the quick convergence of the next alignment error.

(2) The method carries out compass alignment operation for N times and reverse inertial attitude updating algorithm (N-1) times and alignment ending condition judgment for (N-1) times, and the time consumed for running the algorithm is T + (N-1). DELTA.t. Usually, the time of T is selected to be dozens of seconds, the compass algorithm occupies a short program, the time for carrying out one-time centralized continuous operation compass alignment, reverse inertial attitude updating and alignment ending condition judgment by using data with the time length within T is set to be delta T, and the delta T is far smaller than the T. The method consumes T + (N-1). DELTA.t time, but can obtain the alignment precision which can be achieved only by N.T time length data. That is, the method of the present invention can greatly shorten the alignment time while satisfying the alignment accuracy.

Drawings

FIG. 1 is a schematic diagram of a compass-based alignment/inertial navigation fast alignment method according to the present invention;

FIG. 2 is a flowchart illustrating the end of compass alignment procedure according to the present invention;

FIG. 3 is a flow chart of the compass/inertia combination fast alignment method under a large misalignment angle according to the present invention.

Detailed Description

The method of the technical solution of the present invention is shown in fig. 1, the compass alignment end judgment process is shown in fig. 2, the complete step flow chart is shown in fig. 3, and the specific implementation steps are as follows:

(1) firstly, according to the precision requirement and the carrier environment, the time length of the repeated data is determined to be T ═ T_m-t₀Wherein the initial time t₀Has an attitude angle ofIn case of emergencyThe error is large.

(2) Then, from t₀To t_mThe internally running compass is aligned to obtain t_mAttitude angle of timeCompared withAttitude and heading errors are reduced. Since a relatively short time length of T is selected, it is usualThe accuracy requirements are not met. Compass alignment is required to be continued until the precision requirement is met. But this does not meet the rapidity of alignment required for some applications. To increase the speed of alignment. The invention provides the method for repeatedly utilizing the data to carry out next compass alignment, so that the attitude and heading error is further reduced.

(3) Compass alignment is advanced in time. After performing one alignment, the time has reached t_mTime of day, and the next compass alignment needs to be from t₀Starting at a moment, so the text adopts a reverse inertial attitude updating method, using t_mTime t₀Reverse inertial sensor data of time of day willFrom t_mReversely pushing back the moment to obtain the course and the attitude angle corresponding to the moment dataBecause the updating error of the inertial attitude is smaller in a short period, the attitude converged after a period of time can be transmitted to the moment, and a new attitude heading is generated. Andin contrast to the above-mentioned results,closer to the true value. This corresponds to a reduction of the initial error of the time of day data.

(4) Then useAs an initial value, reuse t₀To t_mThe inertial sensor data in the time period and the 2 nd-time running of the compass alignment algorithm obtain smaller errors

(5) Finally, repeating the steps (3) and (4) N-1 times until the alignment precision requirement is metAnd taking the application precision requirement as a judgment basis for the alignment end.

Those skilled in the art will appreciate that the invention may be practiced without these specific details.