CN111123972B - Inertial measurement combined rotation modulation method based on course angle tracking - Google Patents
Inertial measurement combined rotation modulation method based on course angle tracking Download PDFInfo
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- G01C21/10—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration
- G01C21/12—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning
- G01C21/16—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation
- G01C21/165—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 by using measurements of speed or acceleration executed aboard the object being navigated; Dead reckoning by integrating acceleration or speed, i.e. inertial navigation combined with non-inertial navigation instruments
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Abstract
The invention relates to an inertial measurement combined rotation modulation method based on course angle tracking, which comprises the following steps: 1) Electrifying the inertial set to keep the inertial instrument in a normal running state; 2) Sending a navigation instruction to an inertial measurement unit, and enabling a system to enter an initial alignment state; 3) Acquiring inertial measurement unit initial position heading angle psi after alignment 0 And the initial heading angle psi 0 Transmitting to a rotation control system; 4) And the inertial measurement unit enters a navigation state and starts to perform rotation modulation based on course angle tracking. The invention inhibits the horizontal error in the inertial navigation unit navigation process by rotation modulation, thereby improving the navigation precision.
Description
Technical Field
The invention relates to a rotation modulation method in a strapdown inertial measurement combined navigation process, in particular to a strapdown inertial measurement combined rotation modulation method based on course angle tracking.
Background
The strapdown inertial measurement unit (abbreviated as an inertial measurement unit) is widely applied to the technical field of civil and military navigation due to the advantages of small volume, light weight, strong autonomy, comprehensive output parameters and the like, and the performance of the whole navigation system is often determined by the accuracy of the inertial measurement unit. Therefore, it is the focus of modern navigation technology research to improve the performance of the navigation system, i.e. improve the inertial measurement unit precision. There are two aspects of cut-in points in improving the navigation accuracy of the inertial navigation unit: firstly, the precision of an inertia device is improved; and secondly, compensating or eliminating the influence of the error of the inertial device on the navigation precision by an error compensation technology. The rotation modulation technology is an error compensation technology for the inertial measurement unit, the technology controls the inertial measurement unit to rotate according to a certain rotation scheme in a fixed period in the navigation process through a mechanical device, and navigation errors caused by errors of inertial measurement unit devices can be effectively inhibited through rotation and calculation, so that the precision of a navigation system is improved. The following problems tend to exist for conventional rotational modulation techniques:
(1) The common inertial measurement unit can complete rotation modulation only through a rotating mechanism, and the rotating mechanism usually comprises a series of components such as a rotating motor, a rotating shaft, a rotating frame, a sensor and a controller. Both excessive angular overshoots and speed fluctuations during rotation have a negative effect on the error suppression of the rotation modulation.
(2) In the rotation modulation technique, the rotation mechanism rotates according to a specified rotation scheme relative to the geographic coordinate system, but when the rotation mechanism is actually controlled in the inertial set, all the indexing control is relative to the inertial set coordinate system. Therefore, if the inertial set makes angular motion relative to the geographic coordinate system, the motion of the rotating mechanism relative to the geographic coordinate system is not completely the same as the design of the rotating scheme, so that an error of the inertial device cannot be modulated completely and effectively, and even an error compensation effect of the rotation modulation can be completely counteracted under the condition of large angular motion of the inertial set.
A single-axis rotation modulation technology is adopted in the positioning and orientation project, so that the inertial unit rotates around the zenith axis in a regular and continuous reciprocating manner, the device error in the horizontal direction is modulated, and the modulation effect is optimal after the whole rotation period is completed. In practical application, the course of the vehicle changes when the vehicle turns, the starting point and the ending point in the rotation period of the inertial set change compared with the initial moment of the inertial set, and the modulation effect is influenced.
Disclosure of Invention
The invention solves the technical problems that: the method overcomes the defects of the prior art, provides the inertial measurement combination rotation modulation method based on course angle tracking, and inhibits the horizontal error in the navigation process of the inertial measurement unit through rotation modulation, thereby improving the navigation precision.
The technical scheme of the invention is as follows: an inertial measurement combined rotation modulation method based on course angle tracking comprises the following steps:
1) Electrifying the inertial set to keep the inertial instrument in a normal running state;
2) Sending a navigation instruction to an inertial measurement unit, and enabling a system to enter an initial alignment state;
3) Acquiring inertial measurement unit initial position heading angle psi after alignment 0 And the initial heading angle psi 0 Transmitting to a rotation control system;
4) The inertial measurement unit enters a navigation state and starts to carry out rotation modulation based on course angle tracking;
the rotation modulation process is specifically as follows:
(41) The inertial measurement unit enters a navigation state, and the horizontal axis of the inertial measurement unit is positioned from an initial position P in the navigation process 0 Rotated clockwise 360 DEG to P' 0 Then rotates counterclockwise by 360 degrees to P 0 Circularly and reciprocally performing rotary modulation; the inertial measurement unit moves along with the carrier, the course angle psi is updated in real time, and the course angle psi of the inertial measurement unit is transmitted to the rotation control system in real time;
(42) The rotation control system is based on the received psi 0 And psi, calculating to obtain the difference value delta psi = psi-psi between the current inertial measurement combination position heading angle and the initial position heading angle 0 ；
(43) Rotating deviceThe dynamic control system calculates and obtains new transposition information P according to the heading angle difference delta psi 0 + delta psi and P' 0 +Δψ；
(44) The rotation control system calculates and obtains the angle difference value delta P = P between the current position alpha of the horizontal shaft of the inertial measurement unit and the calculated transposition 0 +Δψ-α；
(45) The rotation control system calculates the control quantity of the rotation motor through a PID control algorithm according to the angle difference value
k p ，k i ，k d PID control parameters;
(46) The rotating motor drives the inertial measurement unit to rotate to the calculated transposition according to the control quantity;
(47) Repeating the step (41) to the step (46), and judging whether the inertial unit rotates to the calculated transposition position; if not, returning to the step (44); if so, jumping to step 48);
(48) After reaching the appointed transposition, the rotary modulation device turns to the next rotary modulation position.
The invention has the beneficial effects that:
(1) The joint working mode of the rotation control system and the navigation system is that the rotation control system and the navigation system are in real-time communication;
(2) Through the real-time communication between the rotation control system and the navigation system, the initial position of the rotation period in the rotation modulation process can be corrected in real time according to the course angle sent by the navigation system so as to keep the initial position always the same as the initial position in the geographic coordinate system, so that the rotation debugging effect can still exert the optimal effect when the inertial measurement unit has horizontal angular motion;
(3) The inertial measurement unit applying the rotation modulation method can effectively eliminate errors in the horizontal direction in the navigation process, and brings better navigation precision.
Drawings
FIG. 1 is a flow chart of the rotation modulation method with real-time tracking of course angle according to the present invention.
FIG. 2 is a block diagram of information communication between a navigation system and a rotational control system.
Detailed Description
Selecting one shaft in a two-shaft rotating mechanism of a strapdown inertial measurement unit (called an inertial measurement unit for short) according to the final installation position of the strapdown inertial measurement unit to carry out single-shaft rotation modulation, controlling the single-shaft rotating mechanism to drive the inertial measurement unit to rotate in a motion mode by an inertial measurement unit rotation control system according to sensor information returned by the inertial measurement unit and an angle sensor, and finally realizing that the rotation of the inertial measurement unit rotates relative to a rotation center shaft plane in a rotation period of a geographic coordinate system, and a terminal point of the inertial measurement unit is consistent with a shaft plane at the initial time of the inertial measurement unit and rotates back and forth around the shaft plane in any horizontal angular motion process by correcting a course angle sent by a navigation system in real time by the rotation control system. As shown in fig. 1, the rotational modulation for course angle tracking includes the following steps:
(1) Navigation system completes initial alignment to acquire heading angle psi of initial position 0 And sending the initial heading angle to a rotation control system (as shown in fig. 2);
(2) After initial alignment, the inertial measurement unit enters a navigation working state, a rotation control system performs rotation modulation according to a set rotation modulation scheme in the navigation process, and the transposition information of the rotation modulation scheme is arranged as follows:
21. obtaining an initial value psi of inertial measurement unit course angle when alignment is finished 0 When the carrier and the inertial set rotating mechanism are kept static, the rotation control system records the position information of the inertial set rotating mechanism at the moment and records the position information as a rotation modulation initial position P 0 ；
22. With P 0 Is a primary position rotating mechanism rotates clockwise by 360 degrees to P' 0 Noted as a second position;
23. from P' 0 The second position rotates anticlockwise by 360 degrees and returns to the initial position P 0 ；
24. Repeating steps 22-23;
(3) The inertial navigation system acquires a current position heading angle psi in real time and sends the current position heading angle psi to the rotation control system;
(4) And the rotation control system corrects the position of the rotating central axis according to the real-time course angle information sent by the navigation system, so that the central axis modulated by the rotation of the inertial measurement unit is always consistent with the initial course angle.
The invention has the following implementation steps:
1) Electrifying the inertial set to keep the inertial instrument in a normal running state;
2) Sending a navigation instruction to an inertial measurement unit, and enabling a system to enter an initial alignment state;
3) Acquiring inertial measurement unit initial position course angle psi after alignment 0 And the initial heading angle psi 0 And (2) transmitting the data to a rotation control system, wherein the rotation control system is used for setting corresponding rotation modulation indexes, and the indexes are set as follows (shown in figure 1):
31. obtaining an initial value psi of inertial measurement unit course angle when the alignment is finished 0 When the carrier and the inertial set rotating mechanism are kept static, the rotation control system records the position information of the inertial set rotating mechanism at the moment and records the position information as a rotation modulation initial position P 0 ；
32. With P 0 Is a primary position rotating mechanism rotates clockwise by 360 degrees to P' 0 Recording as a second position;
33. from P' 0 The second position rotates counterclockwise 360 DEG back to the initial position P 0 ；
34. Repeating steps 32-33;
4) And then the inertial measurement unit enters a navigation state, and rotation modulation based on course angle tracking is started, wherein the rotation modulation process specifically comprises the following steps:
(41) The inertial measurement unit enters a navigation state, the inertial measurement unit carries out rotation modulation according to the rotation scheme shown in 3) in the navigation process, the heading angle psi is updated in real time, and the heading angle psi of the inertial measurement unit is transmitted to a rotation control system in real time;
(42) The rotation control system is based on the received psi 0 And psi, calculating to obtain the difference value delta psi = psi-psi between the current inertial measurement combination position course angle and the initial position course angle 0 ；
(43) The rotation control system calculates new transposition information P according to the course angle difference value 0 + delta psi and P' 0 + Δ ψ; the rotation control system calculates and obtains the angle difference value delta P = P between the current position alpha of the horizontal shaft of the inertial measurement unit and the calculated transposition 0 +Δψ-α；
(44) The rotation control system calculates the current position alpha of the horizontal shaft of the inertial measurement unit and calculates the backward rotationAngular difference of bits Δ P = P 0 +Δψ-α；
(45) The rotation control system calculates the control quantity of the rotation motor through a PID control algorithm according to the angle difference value
k p ，k i ，k d For PID control parameter, adopt KI control in this scheme, the control parameter sets up to: k is a radical of p ＝9.5，k i ＝0.01，k d ＝0；
(46) The rotating motor drives the inertial measurement unit to rotate to the calculated transposition P according to the control quantity 0 + delta psi and P' 0 +Δψ；
(47) Repeating the step (41) to the step (46), and judging whether the inertial measurement unit rotates to the calculated transposition position; if not, repeating 44-47; if so, jumping to step 48 (shown in FIG. 1);
(48) After reaching the designated index, the next rotary modulation position is turned and 41-48 are repeated.
Claims (1)
1. An inertial measurement combination rotation modulation method based on course angle tracking is characterized by comprising the following steps:
1) Electrifying the inertial set to keep the inertial instrument in a normal running state;
2) Sending a navigation instruction to an inertial measurement unit, and enabling a system to enter an initial alignment state;
3) Acquiring inertial measurement unit initial position heading angle psi after alignment 0 And the initial heading angle psi 0 Transmitting to a rotation control system;
4) The inertial measurement unit enters a navigation state and starts to carry out rotation modulation based on course angle tracking;
the rotation modulation process is specifically as follows:
(41) The inertial unit enters a navigation state, and the horizontal axis of the inertial unit is positioned from an initial position P in the navigation process 0 Rotated clockwise 360 DEG to P' 0 Then rotates counterclockwise by 360 DEG to P 0 Circularly and reciprocally performing rotary modulation; the inertial group moves along with the carrier, the course angle psi is updated in real time, and the course angle psi of the inertial group is realThe time is transmitted to a rotation control system;
(42) The rotation control system is based on the received psi 0 And psi, calculating to obtain the difference value delta psi = psi-psi between the current inertial measurement combination position course angle and the initial position course angle 0 ；
(43) The rotation control system calculates to obtain new transposition information P according to the heading angle difference delta psi 0 + delta psi and P' 0 +Δψ；
(44) The rotation control system calculates the current position alpha of the horizontal shaft of the inertial measurement unit and the angle difference delta P = P of the calculated transposition 0 +Δψ-α；
(45) The rotation control system calculates the control quantity of the rotation motor through a PID control algorithm according to the angle difference value
k p ，k i ，k d PID control parameters;
(46) The rotating motor drives the inertial measurement unit to rotate to the calculated transposition according to the control quantity;
(47) Repeating the step (41) to the step (46), and judging whether the inertial measurement unit rotates to the calculated transposition position; if not, returning to the step (44); if in place, go to step 48);
(48) After reaching the appointed indexing position, the rotary drum rotates to the next rotary modulation position.
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