Sky channel damping method for correcting zero offset of accelerometer based on FOG-SINS

Abstract

A sky-direction channel damping method for correcting zero offset of an accelerometer based on FOG-SINS comprises the steps that a new model is established, the satellite guide height and the sky-direction speed serve as external reference quantities, the zero offset error of the sky-direction accelerometer is estimated, corrected sky-direction specific force information enters a damping feedback loop, and the zero offset error of the sky-direction accelerometer is calculated. The convergence rate of estimation of the sky-direction speed error and the height error in a loop is increased, so that the sky-direction channel tracking precision of FOG-SINS inertial navigation equipment is improved, and the problem that in an original sky-direction channel damping model, only the height is used as a main reference quantity, the sky-direction specific force error is not corrected, and the precision of the sky-direction channel is reduced is solved. And therefore, the problems of poor sky-direction channel tracking precision and low measurement accuracy in a carrier movement process can be solved.

Description

Technical Field

[0001] The invention relates to a celestial channel damping method for correcting accelerometer zero bias based on FOG-SINS, and is mainly used in the field of airborne optical fiber strapdown inertial navigation. Background Art

[0002] FOG-SINS inertial navigation equipment is a high-precision strapdown inertial navigation system based on fiber optic gyroscope and quartz accelerometer. As the main navigation and measurement equipment of the UAV platform, it can provide real-time information on the carrier's angular motion and linear motion, and is sensitive to the carrier's position, speed, and heading information in real time for body control.

[0003] During the flight, the aircraft provides the FOG-SINS inertial navigation device with satellite navigation speed, position information, and information from other airborne auxiliary equipment such as barometers in real time, which is used to correct the combined navigation errors of the FOG-SINS inertial navigation device.

[0004] Usually, the combined navigation method of FOG-SINS inertial navigation equipment adopts Kalman filtering to establish output correction of 4D observation based on horizontal velocity and horizontal position information, or to establish feedback correction of 6D observation based on three-axis velocity and three-axis position information. Considering the accuracy of instrument error estimation and correction for high-precision inertial measurement equipment, the output correction method is often used. At this time, the damping method needs to be used in the celestial channel direction to suppress error divergence.

[0005] The existing altitude channel damping method only uses altitude information as the main observation quantity, and does not make error correction for the celestial accelerometer. When there is a residual zero bias in the celestial accelerometer, the error will be reflected in the celestial velocity and altitude during the motion of the carrier. In addition, since the system damping coefficient is fixed, and the error of the external altitude reference information is time-varying during the flight, this damping method requires convergence time during the motion change process and cannot quickly track the observation information in a short time. As a result, when the body has a large movement or the quality of the satellite guidance is poor, the measurement accuracy of the FOG-SINS inertial navigation device on the celestial channel is not high. Therefore, it is necessary to seek a method that can effectively and quickly sense the error characteristics of the celestial channel to improve the accuracy of the celestial velocity and altitude of the FOG-SINS inertial navigation device. Summary of the invention

[0006] The technical problem to be solved by the present invention is: the present invention uses altitude and celestial velocity as external input reference quantities, estimates the celestial accelerometer zero bias in real time, and feeds it back to the instrument information, so as to solve the tracking accuracy problem on the celestial channel of the FOG-SINS inertial navigation device.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for FOG-SINS-based celestial channel damping for correcting accelerometer zero bias comprises the following steps:

[0009] Obtain the celestial speed and altitude information of satellite navigation (i.e. satellite navigation) through the communication interface;

[0010] Using the satellite's celestial velocity as a reference, estimate the celestial accelerometer zero bias;

[0011] With the satellite navigation celestial velocity and altitude information as reference quantities and the sensitive celestial force information of the FOG-SINS inertial navigation device as input, a damping loop is established to calculate the carrier celestial velocity and carrier altitude.

[0012] In one embodiment of the present invention, the communication interface adopts any one of RS232 serial port, RS422 serial port, RS485 serial port, 1553B communication interface, Flexray bus, parallel bus interface, CAN interface and Ethernet interface.

[0013] In one embodiment of the present invention, the carrier celestial velocity is the carrier vertical velocity information in a geographic coordinate system (northeast sky).

[0014] In one embodiment of the present invention, the carrier height is the carrier altitude information in a geographic coordinate system (northeast sky).

[0015] In one embodiment of the present invention, the accelerometer zero bias is a residual zero position deviation caused by environmental or calibration deviation after the instrument is calibrated and compensated.

[0016] In one embodiment of the present invention, the accelerometer is a quartz accelerometer.

[0017] A computer-readable storage medium stores computer program instructions, which, when loaded and executed by a processor, cause the processor to execute the above-mentioned antenna channel damping method.

[0018] A computer program product stored on a non-transitory computer-readable medium, the computer program product comprising program codes for implementing the above antenna channel damping method.

[0019] An electronic device, comprising:

[0020] Processor; and

[0021] a memory for storing computer program instructions;

[0022] When the computer program instructions are loaded and executed by the processor, the processor executes the above-mentioned antenna channel damping method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The invention establishes a new model, takes the satellite navigation altitude and celestial velocity as external reference quantities, estimates the celestial accelerometer zero bias error, enters a damping feedback loop with corrected celestial specific force information, accelerates the convergence speed of celestial velocity error and altitude error estimation in the loop, thereby improving the celestial channel tracking accuracy of a FOG-SINS inertial navigation device, and solves the problem that in the original celestial channel damping model, only the altitude is used as the main reference quantity, the celestial specific force error is not corrected, and the celestial channel tracking accuracy is poor and the measurement accuracy is not high during the carrier movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an integral loop diagram established by taking the satellite navigation celestial velocity information as the reference quantity and the inertial loop celestial velocity.

[0026] Figure 2 This is the damping circuit diagram of the celestial channel.

[0027] Figure 3 This is the celestial velocity and altitude curve of the carrier during the movement of the satellite navigation receiver.

[0028] Figure 4 is the celestial accelerometer bias estimated after model solution.

[0029] Figure 5 This is a comparison chart of the carrier celestial velocity and altitude output by the FOG-SINS inertial navigation device and the celestial information input by the satellite navigation.

[0030] Figure 6 This is the processing result diagram of the original anterograde channel damping model. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] A FOG-SINS-based celestial channel damping method for correcting accelerometer zero bias, comprising:

[0033] (1) Obtain the satellite navigation celestial velocity and altitude information through the communication interface. The communication interface adopts any one of RS232 serial port, RS422 serial port, RS485 serial port, 1553B communication interface, Flexray bus, parallel bus interface, CAN interface and Ethernet interface. The satellite navigation celestial velocity and altitude information refer to the celestial velocity information of the carrier under the motion condition in the local geographic coordinate system (northeast sky) and the altitude information of the carrier under the motion condition sensed by the satellite navigation receiver after being fixedly connected to the carrier.

[0034] (2) Using the satellite navigation input celestial velocity as a reference, estimate the celestial accelerometer zero bias.

[0035] Using the satellite navigation celestial velocity information as a reference, an integral loop is established with the inertial loop celestial velocity, such as Figure 1 shown.

[0036] The integral loop relationship is:

[0037]

[0038] In the formula,

[0039] f z0 — is the estimated value of the celestial accelerometer zero position;

[0040] K 3 —Integrating loop coefficient;

[0041] V z —inertial loop celestial velocity;

[0042] V zr —Satellite navigation celestial speed;

[0043] (3) Using the satellite navigation input anterograde velocity and high-speed information as reference quantities and the anterograde specific force information as input quantities, a damping loop is established to calculate the anterograde velocity and altitude of the carrier.

[0044] The reason for the divergence of the inertial loop celestial channel is that the system has no damping, which makes the system have positive characteristic roots. Therefore, the satellite celestial speed and altitude are introduced to make the inertial celestial channel damped.

[0045] Establish the celestial channel damping loop, as shown in 2.

[0046] The damping circuit relationship is:

[0047] S ez =f z -f z0 -a z -gK 2 (V z -V zr )

[0048] sV ez =A ez -K 1 (V z -V zr )

[0049] sH=V ez -K 0 (HH r )

[0050] In the formula,

[0051] f z —Original celestial force;

[0052] a z — harmful acceleration;

[0053] g—normal gravity;

[0054] A ez —The carrier's celestial motion acceleration;

[0055] K 0 —Integrating loop coefficient;

[0056] K 1 , K 2 —damping loop coefficient;

[0057] H—carrier height;

[0058] V ez —vehicle celestial velocity;

[0059] H r —Satellite navigation altitude;

[0060] s—Laplacian operator.

[0061] Example:

[0062] Taking the test data of a sports car in a mountain area using a FOG-SINS inertial navigation device as an example, the application of the method of the present invention is described.

[0063] (1) Connect the RS422 communication interface between the FOG-SINS inertial navigation equipment and the satellite navigation information. According to the established satellite navigation protocol, the celestial velocity and altitude information are obtained. The celestial velocity and altitude curves of the carrier during the movement received by the satellite navigation are as follows: Figure 3 shown.

[0064] (2) Using the satellite navigation input celestial velocity as a reference, estimate the celestial accelerometer zero bias. According to the model in the specific implementation (2), the input quantity V z is the celestial velocity of the inertial loop, reference quantity V zr is the satellite navigation speed in the sky, K 3 =0.003. To verify the accuracy of the zero bias estimation of the model, a zero position deviation of 0.5 mg was set for the celestial accelerometer before data processing. After solving the model, the estimated zero bias of the celestial accelerometer f z0 like Figure 4 As shown, it is basically consistent with the binding zero position deviation.

[0065] (3) Using the satellite navigation input antenna velocity and high speed information as reference quantities and the antenna specific force information as input quantities, a damping loop is established to calculate the antenna velocity and altitude of the carrier. According to the model in the specific implementation method (3), the input quantity Vz is the celestial velocity of the inertial loop, reference quantity V zr is the satellite celestial velocity, the input quantity H is the inertial loop height, and the reference quantity H r is the satellite navigation height, input quantity f z is the original celestial force, and the intermediate process calculation includes: harmful acceleration a z , normal gravity g, carrier celestial motion acceleration A ez , K 0 =0.5,K 1 =0.2,K 2 =0.05. After solving the model, the carrier celestial velocity and altitude output by the FOG-SINS inertial navigation device are compared with the celestial information input by the satellite navigation. Figure 5 As shown (the blue curve is the satellite guidance information, and the red curve is the information of the FOG-SINS output channel), the FOG-SINS azimuth channel output can track the reference value well, and the error converges quickly.

[0066] The processing results of the old model of FOG-SINS antenna channel damping in the prior art are as follows: Figure 6 As shown in the figure (the blue curve is the satellite navigation information in the celestial direction, and the red curve is the celestial channel information output by FOG-SINS), since the celestial accelerometer zero bias error is not compensated, it brings fixed deviations in both the celestial velocity and altitude.

[0067] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

[0068] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for FOG-SINS-based accelerometer bias correction antenna channel damping, characterized in that: include: Obtain the satellite navigation celestial velocity and satellite navigation altitude information; Using the satellite's celestial velocity as a reference, estimate the celestial accelerometer zero bias; With the satellite navigation celestial velocity and altitude information as reference quantities and the sensitive celestial force information of the FOG-SINS inertial navigation device as input, a damping loop is established to calculate the carrier celestial velocity and carrier altitude.

2. The celestial channel damping method according to claim 1, characterized in that: The satellite navigation celestial speed and altitude information can be obtained through any one of the communication interfaces including RS232 serial port, RS422 serial port, RS485 serial port, 1553B communication interface, Flexray bus, parallel bus interface, CAN interface and Ethernet interface.

3. The celestial channel damping method according to claim 1, characterized in that: By establishing an integration loop, the celestial accelerometer zero bias is estimated. The integral loop is: In the formula, f z0 — is the estimated value of the celestial accelerometer zero position; K3—integral loop coefficient; V z —inertial loop celestial velocity; V zr —Satellite celestial speed.

4. The celestial channel damping method according to claim 3, characterized in that: The damping circuit relationship is: sA ez =f z -f z0 -a z -g-K2(V z -V zr ) sV ez =A ez -K1(V z -V zr ) sH=V ez -K0(H-H r ) In the formula, f z —Original celestial force; a z — harmful acceleration; g—normal gravity; A ez —The carrier's celestial motion acceleration; K0—integral loop coefficient; K1, K2—damping circuit coefficients; H—carrier height; V ez —vehicle celestial velocity; H r —Satellite navigation altitude; s—Laplacian operator.

5. The celestial channel damping method according to claim 1, characterized in that: The carrier celestial velocity is the carrier vertical velocity information in the geographic coordinate system.

6. The celestial channel damping method according to claim 1, characterized in that: The carrier height is the carrier altitude information in the geographic coordinate system.

7. The celestial channel damping method according to claim 1, characterized in that: The accelerometer type is a quartz accelerometer.

8. A computer-readable storage medium having computer program instructions stored thereon, wherein when the computer program instructions are loaded and executed by a processor, the processor is caused to execute the method according to any one of claims 1 to 7.

9. A computer program product stored on a non-transitory computer readable medium, the computer program product comprising a program code for carrying out the method according to any one of claims 1 to 7.

10. An electronic device comprising: processor; as well as a memory for storing computer program instructions; When the computer program instructions are loaded and executed by the processor, the processor performs the method according to any one of claims 1 to 7.

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