Navigation error fusion modulation method based on two single-axis rotating inertial navigation systems

Abstract

This invention discloses a navigation error fusion modulation method for a dual-axis rotating inertial navigation system configuration. To meet the needs of joint modulation, the invention improves the currently common four-position single-axis rotation scheme and designs a six-position modulation scheme. Furthermore, the modulation order and switching timing of the rotation schemes of the two rotating inertial navigation systems are rationally designed, fully integrating the motion measurement information of the inertial test units of the two rotating inertial navigation systems when they are stopped. This avoids the coupling of rotational motion with scale factor errors and installation errors, effectively reducing system error accumulation. The accuracy of the system solution using information fusion of two inertial navigation systems is significantly improved compared to a single single-axis rotating inertial navigation system.

Description

Technical Field

[0001] The present invention relates to the field of inertial navigation technology, and in particular to a navigation error fusion modulation method under the configuration of two sets of single-axis rotating inertial navigation systems. Background Art

[0002] An inertial navigation system (INS) is a commonly used navigation system that uses an inertial measurement device (consisting of three orthogonal sets of gyroscopes and accelerometers) to measure the motion of a vehicle in three-dimensional space. This system then uses navigational calculations to obtain navigation information such as the vehicle's velocity, attitude, heading, and position. INS are widely used in aviation, aerospace, and marine navigation due to their high autonomy and good stealth. However, due to the integration involved in the navigational calculations, when errors in the INS exist, the navigation system error increases over time. To mitigate the impact of device error sources on system accuracy, a common approach is to add a rotating mechanism to the INS's inertial measurement unit (IMU) to modulate the system's constant and slowly varying error sources. INS systems employing rotational modulation are called rotating INS systems. Furthermore, in rotating INS systems, rotational motion can couple with error sources such as scale factor error and installation error, generating additional errors. Therefore, a properly designed INS rotation scheme is a key technology for improving system accuracy. In the marine field, to improve system reliability, two identical rotating INS systems are typically deployed on the moving vehicle. At present, the two systems use exactly the same rotation scheme, backing up and complementing each other. The information between the systems is independent of each other, and the degree of information fusion is limited. The accuracy of the two systems is equivalent to that of a single system.

[0003] Currently, researchers have conducted research on the calibration and fusion of information from two inertial navigation systems (INS) on ships. Liu Weiren (Liu Weiren, Wang Ning, Liu Guobin, Nian Haitao, Ai Guangbin, A dual-INS combined navigation method [J], Journal of Chinese Inertial Technology, 2014, 22(01)) proposed using the outputs of two INS as observations to estimate and compensate for system errors, given the different error characteristics of platform-based INS and rotating INS. This method is based on the assumption that the two INS have different technical systems and error characteristics. Currently, most typical surface ships are equipped with two rotating INS systems of the same technical system, making this method difficult to apply. Ben Yueyang (Ben Yueyang; Zang Xinle; Zhao Yuxin et al., A method for rapid autonomous readjustment of dual inertial navigation systems based on one-point position information [P], CN201910609900.9, 2019) uses the short-term position accuracy of the inertial navigation system after one-point position correction to achieve error estimation and readjustment of the other inertial navigation system. This is essentially to complete the error readjustment of a single system and cannot substantially improve the accuracy potential of the two systems. Cui Jiarui (Cui Jiarui, Wu Wenqi, Ma Tiefeng, A method for self-correction of scale factor error of dual inertial navigation combined with rotational modulation fiber optic gyroscope [J], Journal of Chinese Inertial Technology, 2022, 30(05)) proposed a method for correcting the scale factor error of fiber optic gyroscope based on two sets of three-axis rotating inertial navigation systems, which effectively improved the system accuracy. However, this method requires the spatial angle relationship between the horizontal rotation axes of the three-axis frame, so it is difficult to apply to single-axis and dual-axis rotating inertial navigation systems. Wu Wenqi et al. (Wu Wenqi, Wang Lin, Pan Xianfei, He Xiaofeng, Hu Xiaoping, "A Dual-INS Joint Rotational Modulation Navigation and Online Relative Performance Evaluation [P]," CN201510390333.4, 2015) invented a dual-INS joint rotational modulation navigation and online relative performance evaluation method. By combining rotational modulation strategy arrangement and filter estimation, they achieved online evaluation of INS performance. This invention primarily provided support for INS system fault diagnosis from a performance evaluation perspective and failed to improve INS system accuracy.

[0004] Currently, error estimation and compensation between multiple inertial navigation systems primarily focuses on error estimation techniques based on navigation output observations, with limited attention paid to the integration of inertial device output information. The key issue addressed by this invention is how to utilize the redundant information measured by the inertial devices in the configuration of two rotating inertial navigation systems, rationally design the rotation modulation scheme for the two inertial navigation systems, integrate the measurement information of the two systems' devices, and minimize the negative impact of rotational motion. Summary of the Invention

[0005] The purpose of the present invention is to provide a navigation error fusion modulation method under the configuration of two single-axis rotating inertial navigation systems. The present invention improves the navigation accuracy of the system by effectively utilizing the inertial measurement information under different rotation schemes by jointly designing the rotation order, rotation timing, and information processing flow of the two rotating inertial navigation systems.

[0006] To achieve this purpose, the present invention designs a navigation error fusion modulation method under the configuration of two single-axis rotating inertial navigation systems, which includes the following steps:

[0007] Step 1: For a carrier equipped with two single-axis rotating inertial navigation systems, set the center of mass of the inertial measurement unit in the first single-axis rotating inertial navigation system as the origin of the first carrier coordinate system based on the orientation of the first single-axis rotating inertial navigation system installed on the carrier. In the transverse cross-section of the carrier, select the axis pointing to the right of the inertial measurement unit in the first single-axis rotating inertial navigation system as the X-axis of the first carrier coordinate system, the axis pointing to the front of the inertial measurement unit in the first single-axis rotating inertial navigation system as the Y-axis of the first carrier coordinate system, and the axis pointing to the top of the inertial measurement unit in the first single-axis rotating inertial navigation system as the Z-axis of the first carrier coordinate system.

[0008] Set the center of mass of the inertial measurement unit in the second single-axis rotation inertial navigation system as the coordinate origin of the second carrier coordinate system. In the carrier transverse section, select the axis pointing to the right of the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system X-axis, the axis pointing to the front of the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system Y-axis, and the axis pointing above the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system Z-axis.

[0009] Step 2: Set the rotation axis of the inertial measurement unit in the first single-axis rotation inertial navigation system as the Z axis of the first carrier coordinate system, and the rotation axis of the inertial measurement unit in the second single-axis rotation inertial navigation system as the Z axis of the second carrier coordinate system;

[0010] Step 3: At the initial moment, the first rotating coordinate system of the inertial measurement unit in the first single-axis rotating inertial navigation system coincides with the first carrier coordinate system, and the second rotating coordinate system of the inertial measurement unit in the second single-axis rotating inertial navigation system coincides with the second carrier coordinate system;

[0011] Step 4: Set the rotation period and number of stop positions of the inertial measurement units around the corresponding rotation axes in the two single-axis rotation inertial navigation systems;

[0012] Step 5: Start a rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system, set the rotation direction, rotation angular velocity, rotation angle and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under each preset rotation order in the rotation cycle, and set the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after each preset rotation order in the rotation cycle ends;

[0013] Step 6: After the inertial measurement unit in the first single-axis rotation inertial navigation system ends a rotation cycle, a preset time interval is set to start a rotation cycle of the inertial measurement unit in the second single-axis rotation inertial navigation system, and the rotation direction, rotation angular velocity, rotation angle and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under each preset rotation order in one rotation cycle are set, and the stop time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stop position after each preset rotation order in one rotation cycle is set;

[0014] Step 7: Utilize the angular velocity data output by the gyroscope inside the inertial measurement unit and the real-time acceleration data output by the accelerometer during one rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system;

[0015] Acquire angular velocity data output by a gyroscope and real-time acceleration data output by an accelerometer of an inertial measurement unit in a second single-axis rotational inertial navigation system during one rotation cycle;

[0016] For each selected time period within each rotation cycle, a strapdown inertial navigation system navigation solution is performed using the angular velocity data output by the gyroscope and the real-time acceleration data output by the accelerometer of the first single-axis rotation inertial navigation system in the previous time period of the adjacent time period, and the angular velocity data output by the gyroscope and the real-time acceleration data output by the accelerometer of the second single-axis rotation inertial navigation system in the next time period of the adjacent time period to obtain the real-time speed, attitude heading and position information of the carrier in each rotation cycle.

[0017] Based on the current configuration status of two sets of single-axis rotating inertial navigation systems commonly used on surface ships, the present invention systematically sorts out the error characteristics of single-axis rotating inertial navigation systems, and proposes a fusion modulation scheme for carrier navigation system errors by jointly optimizing the rotation order, rotation timing, information processing and other links of the inertial measurement units in the two rotating inertial navigation systems. In response to the needs of joint modulation, this scheme improves the current common four-position single-axis rotation scheme and designs a six-position modulation scheme; at the same time, it rationally designs the modulation order and conversion timing of the rotation schemes of the two rotating inertial navigation systems, fully integrates the motion measurement information of the inertial measurement units of the two rotating inertial navigation systems when they are stopped, avoids the coupling of rotational motion with scale coefficient errors and installation errors, and effectively reduces the accumulation of system errors. The accuracy of the system solution using the fusion of two inertial navigation information has been significantly improved compared to a single single-axis rotating inertial navigation system.

[0018] The navigation error fusion modulation scheme provided by the present invention is based on the current configuration status of two single-axis rotating inertial navigation systems on surface ships. Without changing the system's installation method and location on the ship and without increasing the system's cost and complexity, the present invention optimizes the system's single-axis rotation scheme and is based on error fusion modulation between the two inertial navigation systems. The main features and advantages of the present invention are as follows:

[0019] (1) The installation method and location of the two systems on the ship do not change, nor does it change the internal hardware structure of the system, and does not increase the system cost and complexity. The navigation error fusion modulation scheme provided by the present invention is directly based on the two single-axis rotating inertial navigation systems installed on the surface ship. By controlling the rotation order and timing of the two single-axis rotating inertial navigation systems, when implementing this error modulation method, it is only necessary to control the inertial measurement units of the two inertial navigation systems through time synchronization and rotation control programs. This does not change the system hardware structure and does not increase the system cost and complexity.

[0020] (2) Effectively avoid the coupling effect between rotational motion and system error sources in a single rotating inertial navigation system. Error modulation is performed based on two inertial navigation systems. By rationally designing the system rotation scheme, the gyroscope and accelerometer measurement information of the inertial measurement units of the two rotating inertial navigation systems at the moment of rest are combined to effectively avoid the coupling effect between the gyroscope and accelerometer measurement information of the rotating inertial navigation system during rotation, thereby avoiding the coupling effect between rotational motion and error sources such as scale factor error and installation error.

[0021] (3) Effectively reduces the attitude and velocity oscillation errors solved by a single system. When a single rotating inertial navigation system executes a rotation scheme, the system attitude error is affected by the rotational motion due to factors such as the non-orthogonality and shaking of the rotating axis system, and the solution of the attitude information has a large oscillation error. At the same time, the attitude error will cause the accumulation of velocity error, thereby causing large velocity oscillation error and sawtooth error. The navigation error fusion modulation scheme intermittently selects the motion measurement information of the two inertial navigation systems when they stop, and obtains the carrier attitude through navigation solution, effectively reducing the system's attitude and velocity oscillation errors.

[0022] (4) Effectively reduces the longitude and latitude errors of the system and improves the navigation accuracy of the system. In a single rotating inertial navigation system, the asymmetric error of the scale coefficients of the gyroscope and accelerometer cannot be modulated, and the coupling with the rotational motion produces equivalent drift. The navigation error fusion modulation scheme reasonably selects the gyroscope and accelerometer outputs of the inertial measurement unit at the time of stopping, effectively avoiding the asymmetric error of the excitation scale coefficient and reducing the equivalent device drift error, thereby reducing the attitude, velocity and longitude and latitude errors caused by this, and improving the navigation accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The rotation order diagram of the single-axis rotating inertial navigation system rotation scheme;

[0024] Figure 2 For Figure 1 The Z-axis angular velocity timing and navigation error fusion modulation scheme for two single-axis rotating inertial navigation systems in the rotation order shown. When performing navigation error fusion modulation for two single-axis rotating inertial navigation systems, the inertial navigation solution uses the gyroscope and accelerometer measurements during the red period in the angular velocity timing series of the two rotating inertial navigation systems.

[0025] Figure 3 It is the velocity error during navigation solution of two single-axis rotating inertial navigation systems and navigation error fusion modulation scheme within one rotation period.

[0026] Figure 4 It is the attitude error during navigation solution of two sets of single-axis rotating inertial navigation systems and navigation error fusion modulation scheme.

[0027] Figure 5 It is the attitude error solved by two sets of single-axis rotating inertial navigation systems and navigation error fusion modulation scheme during long-duration (72 hours) navigation.

[0028] Figure 6 Velocity error calculated for long-duration (72 hours) navigation using two single-axis rotating inertial navigation systems and a navigation error fusion modulation scheme.

[0029] Figure 7It is the position error solved by two single-axis rotating inertial navigation systems and navigation error fusion modulation scheme in long-duration (72 hours) navigation. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0031] like Figures 1 to 7 The navigation error fusion modulation method for the two single-axis rotating inertial navigation system configuration shown includes the following steps:

[0032] Step 1: For a carrier equipped with two single-axis rotating inertial navigation systems, set the center of mass of the inertial measurement unit in the first single-axis rotating inertial navigation system as the origin of the first carrier coordinate system based on the orientation of the first single-axis rotating inertial navigation system installed on the carrier. In the transverse cross-section of the carrier, select the axis pointing to the right of the inertial measurement unit in the first single-axis rotating inertial navigation system as the X-axis of the first carrier coordinate system, the axis pointing to the front of the inertial measurement unit in the first single-axis rotating inertial navigation system as the Y-axis of the first carrier coordinate system, and the axis pointing to the top of the inertial measurement unit in the first single-axis rotating inertial navigation system as the Z-axis of the first carrier coordinate system.

[0033] Set the center of mass of the inertial measurement unit in the second single-axis rotation inertial navigation system as the coordinate origin of the second carrier coordinate system. In the carrier transverse section, select the axis pointing to the right of the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system X-axis, the axis pointing to the front of the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system Y-axis, and the axis pointing above the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system Z-axis.

[0034] Step 2: Set the rotation axis of the inertial measurement unit in the first single-axis rotation inertial navigation system as the Z axis of the first carrier coordinate system, and the rotation axis of the inertial measurement unit in the second single-axis rotation inertial navigation system as the Z axis of the second carrier coordinate system;

[0035] Step 3: At the initial moment, the first rotating coordinate system of the inertial measurement unit in the first single-axis rotating inertial navigation system coincides with the first carrier coordinate system, and the second rotating coordinate system of the inertial measurement unit in the second single-axis rotating inertial navigation system coincides with the second carrier coordinate system;

[0036] Step 4: Set the rotation period and number of stop positions of the inertial measurement units around the corresponding rotation axes in the two single-axis rotation inertial navigation systems;

[0037] Step 5: Start a rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system, set the rotation direction, rotation angular velocity, rotation angle and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under each preset rotation order in the rotation cycle, and set the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after each preset rotation order in the rotation cycle ends;

[0038] Step 6: After the inertial measurement unit in the first single-axis rotation inertial navigation system ends a rotation cycle, a preset time interval is set to start a rotation cycle of the inertial measurement unit in the second single-axis rotation inertial navigation system, and the rotation direction, rotation angular velocity, rotation angle and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under each preset rotation order in one rotation cycle are set, and the stop time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stop position after each preset rotation order in one rotation cycle is set;

[0039] Step 7: Utilize the angular velocity data output by the gyroscope inside the inertial measurement unit and the real-time acceleration data output by the accelerometer during one rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system;

[0040] Acquire angular velocity data output by a gyroscope and real-time acceleration data output by an accelerometer of an inertial measurement unit in a second single-axis rotational inertial navigation system during one rotation cycle;

[0041] For each selected time period within each rotation cycle, a strapdown inertial navigation system navigation solution is performed using the angular velocity data output by the gyroscope and the real-time acceleration data output by the accelerometer of the first single-axis rotation inertial navigation system in the previous time period of the adjacent time period, and the angular velocity data output by the gyroscope and the real-time acceleration data output by the accelerometer of the second single-axis rotation inertial navigation system in the next time period of the adjacent time period to obtain the real-time speed, attitude heading and position information of the carrier in each rotation cycle.

[0042] In step 4 of the above technical solution, the attitude and heading information [θ0, γ0, φ0] after the initial alignment of the first set of single-axis rotating inertial navigation system is obtained, and the initial velocity V0 and position information of the carrier are obtained.

[0043] In step 7, the attitude and heading information [θ0, γ0, φ0] after the initial alignment of the first single-axis rotating inertial navigation system is used, and each selected time period in each rotation cycle is used. The angular velocity data output by the gyroscope inside the first single-axis rotating inertial navigation system in the previous time period in the adjacent time period is used. The real-time acceleration data fb output by the accelerometer and the angular velocity data output by the gyroscope inside the second single-axis rotation inertial navigation system in the latter time period of the adjacent time period The real-time acceleration data fb output by the accelerometer is used to perform strapdown inertial navigation system navigation solution to obtain the real-time speed V, attitude heading [θ, γ, φ] and position information of the carrier in each rotation cycle.

[0044] In step 7, the strapdown inertial navigation system is used to calculate the real-time speed V, attitude heading [θ, γ, φ] and position information of the carrier in each rotation cycle. The specific method is:

[0045] Angular velocity data output by the gyroscope Get the carrier's attitude angular rate The angular velocity data output by the gyroscope The angular velocity data output by the gyroscope inside the first single-axis rotation inertial navigation system And the angular velocity data output by the gyroscope inside the second single-axis rotation inertial navigation system The sequence of components;

[0046]

[0047] The angular velocity of the Earth Carrier motion angular velocity And the posture matrix The Earth's angular velocity constant ω ie , the velocity of the carrier at a moment V=[V x V y V z ],Location The posture [θ, γ, φ] is calculated, and the posture matrix is a matrix The transposed matrix of is as follows:

[0048]

[0049]

[0050]

[0051] Among them, V x It represents the eastward velocity component of the carrier at a certain moment, V y Indicates the northward velocity component of the carrier at a certain moment, V z represents the celestial velocity component of the carrier at a certain moment, λ represents the longitude of the carrier at a certain moment, represents the latitude of the carrier at the last moment, θ represents the roll information of the carrier at the last moment, γ represents the pitch information of the carrier at the last moment, and φ represents the heading information of the carrier at the last moment. It represents the east component of the carrier's attitude angular rate, Indicates the north component of the carrier's attitude angular rate, It represents the celestial component of the carrier's attitude angular rate, and R represents the radius of the earth;

[0052] When obtaining the carrier's attitude angular rate Then, solve the following differential equation to get the gyroscope attitude matrix at this moment:

[0053]

[0054] in, Represents the gyroscope attitude matrix The differential of

[0055] Let the obtained carrier's posture matrix be Based on this, the carrier's posture at this moment [θ, γ, φ] can be obtained and calculated as follows:

[0056] θ=sin -1 C 32

[0057]

[0058]

[0059] At the same time, the posture matrix of the carrier is obtained Then, using the real-time acceleration data of the speedometer f b , according to the carrier's velocity V=[V x V y V z ], the acceleration of gravity g, and the angular velocity of the Earth Angular rate of motion Solving the following differential equations can yield the carrier velocity V at this moment and the real-time acceleration data f b is the real-time acceleration data f output by the accelerometer inside the first single-axis rotation inertial navigation system b 1 and the real-time acceleration data f output by the accelerometer inside the second single-axis rotation inertial navigation system b 2 composed of a sequence:

[0060]

[0061] in, Represents the differential of the carrier velocity V. After obtaining the carrier velocity V, according to the carrier latitude at the previous moment The radius of the earth is R. Solving the following differential equation can give the position at the next moment.

[0062]

[0063]

[0064] in, represents the rate of change of the carrier's latitude, Indicates the rate of change of the carrier's longitude.

[0065] The initial conditions required for solving the above differential equations are the initial posture [θ0, γ0, φ0], initial velocity V0 and initial position Substitute into the calculation.

[0066] In step 5 of the above technical solution, one rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system includes six preset rotation orders;

[0067] Step 5 includes the following steps:

[0068] Step 501: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the first preset rotation order;

[0069] Step 502: determining the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after the first preset rotation sequence is completed;

[0070] Step 503: determining the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the second preset rotation order;

[0071] Step 504: determining the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the second preset rotation sequence is completed;

[0072] Step 505: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the third preset rotation order;

[0073] Step 506: determining the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after the third preset rotation sequence is completed;

[0074] Step 507: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the fourth preset rotation order;

[0075] Step 508: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the fourth preset rotation order is completed;

[0076] Step 509: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the fifth preset rotation order;

[0077] Step 510: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the fifth preset rotation sequence is completed;

[0078] Step 511: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the sixth preset rotation order;

[0079] Step 512: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the sixth preset rotation sequence is completed.

[0080] In step 6 of the above technical solution, one rotation cycle of the inertial measurement unit in the second single-axis rotation inertial navigation system includes six preset rotation orders, and the six preset rotation orders of the inertial measurement unit in the second single-axis rotation inertial navigation system correspond one-to-one to the six preset rotation orders of the inertial measurement unit in the first single-axis rotation inertial navigation system;

[0081] Step 6 includes the following steps:

[0082] Step 601: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the first preset rotation order;

[0083] Step 602: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the first preset rotation sequence is completed;

[0084] Step 603: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the second preset rotation order;

[0085] Step 604: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the second preset rotation sequence is completed;

[0086] Step 605: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the third preset rotation order;

[0087] Step 606: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the third preset rotation sequence is completed;

[0088] Step 607: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the fourth preset rotation order;

[0089] Step 608: Determine the stop time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stop position after the fourth preset rotation sequence is completed;

[0090] Step 609: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the fifth preset rotation order;

[0091] Step 610: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the fifth preset rotation sequence is completed;

[0092] Step 611: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the sixth preset rotation order;

[0093] Step 612: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the sixth preset rotation sequence is completed.

[0094] In the above technical solution, the first set of single-axis rotating inertial navigation system and the second set of single-axis rotating inertial navigation system stop at the initial position A for a time of t s , at this time the attitude conversion matrix of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system Both are:

[0095]

[0096] The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the first rotation order is positive rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have:

[0097]

[0098] The angular velocity of the inertial measurement unit in the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system rotating around the rotation axis is ω;

[0099] The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position B after the first rotation order is completed is t s , the attitude transformation matrix is have:

[0100]

[0101] In the above technical solution, the rotation direction of the inertial measurement unit of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system in the second rotation order are both reversed around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π, and the attitude transformation matrices are all have:

[0102]

[0103] The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position D after the second rotation order is completed is t s , the attitude transformation matrix is have:

[0104]

[0105] In the above technical solution, the rotation direction of the inertial measurement unit of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system in the third rotation order are both reversed around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π, and the attitude transformation matrices are all have:

[0106]

[0107] The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position B after the third rotation sequence is t s , the attitude transformation matrix is have:

[0108]

[0109] In the above technical solution, the rotation direction of the inertial measurement unit of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system in the fourth rotation order are both forward rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π2, and the attitude transformation matrices are all have:

[0110]

[0111] The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position C after the fourth rotation order is t s , the attitude transformation matrix is have:

[0112]

[0113] In the above technical solution, the rotation direction of the inertial measurement unit of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system in the fifth rotation order are both forward rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have:

[0114]

[0115] The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position D after the fifth rotation order is t s , the attitude transformation matrix is have:

[0116]

[0117] In the above technical solution, the rotation direction of the inertial measurement unit of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system in the sixth rotation order are both forward rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have:

[0118]

[0119] The inertial measurement units of the first and second single-axis rotating inertial navigation systems return to position A after the sixth rotation order, and the attitude transformation matrices are both That is the position and posture transformation matrix when stopping for the first time.

[0120] In the step 7,

[0121] The constant error of the gyroscope in the inertial measurement unit of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system is obtained as ε p , the scale coefficient error matrix is δK g , the installation error matrix is δA g , define the constant error of the accelerometer as The scale factor error matrix is δK a , the installation error matrix is δA a ,have:

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128] Where, are the gyro constant errors on the X, Y, and Z axes in the rotating coordinate systems of the two inertial navigation systems, are the constant errors of the accelerometers on the X, Y, and Z axes in the rotating coordinate systems of the two inertial navigation systems. gx ,δK gy ,δK gz are the scale coefficient errors of the gyroscopes on the X, Y, and Z axes of the two inertial navigation systems, δA gxy ,δA gxz ,δA gyx ,δA gyz ,δA gzx ,δA gzy They are the six non-orthogonal installation angles of the gyroscopes on the X, Y, and Z axes of the two inertial navigation systems, δK ax ,δK ay ,δK az are the scale coefficient errors of the accelerometers on the X, Y, and Z axes of the two inertial navigation systems, δA axy ,δA axz ,δA ayx ,δA ayz ,δA azx ,δA azy These are the six non-orthogonal installation angles of the accelerometers on the X, Y, and Z axes of the two inertial navigation systems.

[0129] In step 7, when calculating the real-time speed, attitude, heading and position information of the carrier in each rotation cycle, the above-mentioned errors of the gyroscope and accelerometer are compensated.

[0130] In the above technical solution, the angular velocity of the inertial measurement unit in the two single-axis rotating inertial navigation systems around the rotation axis is ω. According to the rotation scheme, the rotation angles under different rotation orders are determined to be π2 and π respectively (the two rotations are the same, but the rotation start time is different. A complete rotation cycle contains 6 rotation stages (orders), some orders rotate π2, and some orders rotate π). The rotation time under each order is t corresponding to the above rotation angles π / 2 and π respectively. r and 2t r , the number of stop positions is 6, and the stop time at each position is t s , the rotation period is T=10×(t r +t s ).

[0131] In order to verify the feasibility and effectiveness of the navigation error fusion modulation scheme under the configuration of two single-axis rotating inertial navigation systems provided by the present invention, error simulation verification of the navigation error fusion modulation scheme is carried out.

[0132] Step A: Based on the mechanical arrangement of the rotating inertial navigation system, two sets of single-axis rotating inertial navigation system models are constructed to simulate the gyroscope and accelerometer outputs of the system under static conditions;

[0133] Step B: Based on the current level of surface ship inertial navigation devices and systems, the zero bias of the gyroscope of the first single-axis rotating inertial navigation system is set to 0.001°. h , random walk coefficient The symmetrical scale factor error of the three gyroscopes is 5ppm, the asymmetrical scale factor error is 1ppm, and the installation error is 3". The zero bias of the accelerometer is 8μg, the random noise is 1μg, the scale factor error of the three accelerometers is 5ppm, the asymmetrical scale factor error is 1ppm, and the installation error is 3".

[0134] Step C: Based on the current level of surface ship inertial navigation devices and systems, the gyroscope zero bias of the second single-axis rotation inertial navigation system is set to 0.0015°. h , random walk coefficient The symmetrical scale factor error of the three gyroscopes is 3ppm, the asymmetrical scale factor error is 1ppm, and the installation error is 5". The zero bias of the accelerometer is 10μg, the random noise is 1μg, the scale factor error of the three accelerometers is 3ppm, the asymmetrical scale factor error is 1ppm, and the installation error is 5".

[0135] Step D: Determine that the angular velocity of the inertial measurement unit about the Z axis is 3° / s, and the dwell time at each position after rotating to the specified position is 60 seconds;

[0136] Step E: Perform error simulations on two single-axis rotation inertial navigation system solutions and navigation error fusion modulation solutions respectively to obtain attitude, velocity, and latitude and longitude error data of the three system solutions;

[0137] Step F: Draw attitude error curves of the two single-axis rotation inertial navigation system solutions and the navigation error fusion modulation solution within one rotation cycle;

[0138] Step G: Draw velocity error curves of two sets of single-axis rotation inertial navigation system solutions and navigation error fusion modulation solutions within one rotation cycle;

[0139] Step H: Draw graphs of attitude error, velocity error, and position error for the two single-axis rotation inertial navigation system solutions and the navigation error fusion modulation solution for long-duration (72h) flight.

[0140] The simulation results show that: from steps A to G and the attached Figures 3-4 It can be seen that the navigation error fusion modulation scheme proposed in this paper under the configuration of two rotating inertial navigation systems can effectively reduce the coupling of rotational motion with scale factor error and installation error, and significantly improve the attitude error and velocity error within one cycle. Figures 5-6 It can be seen that the attitude and velocity errors within one cycle suppress the attitude and velocity error amplitude of the system during long flight. At the same time, since the scheme uses the inertial measurement output when stopped, it avoids the equivalent drift caused by the asymmetric error of the scale factor, thereby improving the positioning accuracy of the system. Figure 7 It can be seen that the navigation error fusion modulation scheme provided in this paper significantly reduces the divergence speed of the system positioning error and improves the positioning accuracy of the system.

[0141] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A navigation error fusion modulation method for two single-axis rotating inertial navigation systems, characterized in that: It includes the following steps: Step 1: For a carrier equipped with two single-axis rotating inertial navigation systems, set the center of mass of the inertial measurement unit in the first single-axis rotating inertial navigation system as the origin of the first carrier coordinate system based on the orientation of the first single-axis rotating inertial navigation system installed on the carrier. In the transverse cross-section of the carrier, select the axis pointing to the right of the inertial measurement unit in the first single-axis rotating inertial navigation system as the X-axis of the first carrier coordinate system, the axis pointing to the front of the inertial measurement unit in the first single-axis rotating inertial navigation system as the Y-axis of the first carrier coordinate system, and the axis pointing to the top of the inertial measurement unit in the first single-axis rotating inertial navigation system as the Z-axis of the first carrier coordinate system. Set the center of mass of the inertial measurement unit in the second single-axis rotation inertial navigation system as the coordinate origin of the second carrier coordinate system. In the carrier transverse section, select the axis pointing to the right of the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system X-axis, the axis pointing to the front of the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system Y-axis, and the axis pointing above the inertial measurement unit in the second single-axis rotation inertial navigation system as the second carrier coordinate system Z-axis. Step 2: Set the rotation axis of the inertial measurement unit in the first single-axis rotation inertial navigation system as the Z axis of the first carrier coordinate system, and the rotation axis of the inertial measurement unit in the second single-axis rotation inertial navigation system as the Z axis of the second carrier coordinate system; Step 3: At the initial moment, the first rotating coordinate system of the inertial measurement unit in the first single-axis rotating inertial navigation system coincides with the first carrier coordinate system, and the second rotating coordinate system of the inertial measurement unit in the second single-axis rotating inertial navigation system coincides with the second carrier coordinate system; Step 4: Set the rotation period and number of stop positions of the inertial measurement units around the corresponding rotation axes in the two single-axis rotation inertial navigation systems; Step 5: Start a rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system, set the rotation direction, rotation angular velocity, rotation angle and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under each preset rotation order in the rotation cycle, and set the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after each preset rotation order in the rotation cycle ends; Step 6: After the inertial measurement unit in the first single-axis rotation inertial navigation system ends a rotation cycle, a preset time interval is set to start a rotation cycle of the inertial measurement unit in the second single-axis rotation inertial navigation system, and the rotation direction, rotation angular velocity, rotation angle and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under each preset rotation order in one rotation cycle are set, and the stop time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stop position after each preset rotation order in one rotation cycle is set; Step 7: Utilize the angular velocity data output by the gyroscope inside the inertial measurement unit and the real-time acceleration data output by the accelerometer during one rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system; Acquire angular velocity data output by a gyroscope and real-time acceleration data output by an accelerometer of an inertial measurement unit in a second single-axis rotational inertial navigation system during one rotation cycle; For each selected time period within each rotation cycle, a strapdown inertial navigation system navigation solution is performed using the angular velocity data output by the gyroscope and the real-time acceleration data output by the accelerometer of the first single-axis rotation inertial navigation system in the previous time period of the adjacent time period, and the angular velocity data output by the gyroscope and the real-time acceleration data output by the accelerometer of the second single-axis rotation inertial navigation system in the next time period of the adjacent time period to obtain the real-time speed, attitude heading and position information of the carrier in each rotation cycle.

2. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 1, characterized in that: In step 4, the attitude and heading information [θ0, γ0, φ0] after the initial alignment of the first set of single-axis rotating inertial navigation system are obtained, and the initial velocity V0 and position information of the carrier are obtained. In step 7, the attitude and heading information after the initial alignment of the first set of single-axis rotation inertial navigation system, the initial speed V0 and position information of the carrier are used. For each selected time period within each rotation cycle, the angular velocity data output by the gyroscope inside the first single-axis rotation inertial navigation system in the previous time period in the adjacent time period is used. And the real-time acceleration data f output by the accelerometer b 1, and the angular velocity data output by the gyroscope inside the second single-axis rotation inertial navigation system in the next adjacent time period And the real-time acceleration data f output by the accelerometer b 2. Perform strapdown inertial navigation system navigation solution to obtain the real-time velocity V, attitude heading [θ, γ, φ] and position information of the carrier in each rotation cycle 3. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 1, characterized in that: In step 5, one rotation cycle of the inertial measurement unit in the first single-axis rotation inertial navigation system includes six preset rotation orders; Step 5 includes the following steps: Step 501: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the first preset rotation order; Step 502: determining the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after the first preset rotation sequence is completed; Step 503: determining the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the second preset rotation order; Step 504: determining the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the second preset rotation sequence is completed; Step 505: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the third preset rotation order; Step 506: determining the stop time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stop position after the third preset rotation sequence is completed; Step 507: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the fourth preset rotation order; Step 508: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the fourth preset rotation order is completed; Step 509: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the fifth preset rotation order; Step 510: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the fifth preset rotation sequence is completed; Step 511: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system under the sixth preset rotation order; Step 512: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the first single-axis rotation inertial navigation system at the set stopping position after the sixth preset rotation sequence is completed.

4. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 3, characterized in that: In step 6, one rotation cycle of the inertial measurement unit in the second single-axis rotation inertial navigation system includes six preset rotation orders, and the six preset rotation orders of the inertial measurement unit in the second single-axis rotation inertial navigation system correspond one-to-one to the six preset rotation orders of the inertial measurement unit in the first single-axis rotation inertial navigation system; Step 6 includes the following steps: Step 601: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the first preset rotation order; Step 602: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the first preset rotation sequence is completed; Step 603: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the second preset rotation order; Step 604: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the second preset rotation sequence is completed; Step 605: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the third preset rotation order; Step 606: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the third preset rotation sequence is completed; Step 607: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the fourth preset rotation order; Step 608: Determine the stop time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stop position after the fourth preset rotation sequence is completed; Step 609: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the fifth preset rotation order; Step 610: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the fifth preset rotation sequence is completed; Step 611: Determine the rotation direction, rotation angular velocity, rotation angle, and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system under the sixth preset rotation order; Step 612: Determine the stopping time and attitude conversion matrix of the inertial measurement unit in the second single-axis rotation inertial navigation system at the set stopping position after the sixth preset rotation sequence is completed.

5. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 4, characterized in that: The stopping time of the first and second single-axis rotating inertial navigation systems at the initial position A after initial alignment is t s , at this time the attitude conversion matrix of the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system Both are: The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the first rotation order is positive rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have: The angular velocity of the inertial measurement unit in the first single-axis rotating inertial navigation system and the second single-axis rotating inertial navigation system rotating around the rotation axis is ω; The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position B after the first rotation order is completed is t s , the attitude transformation matrix is have:

6. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 4, characterized in that: The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the second rotation order is reversed around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π, and the attitude transformation matrices are all have: The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position D after the second rotation order is completed is t s , the attitude transformation matrix is have:

7. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 4, characterized in that: The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the third rotation order is reversed around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π, and the attitude transformation matrices are all have: The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position B after the third rotation sequence is t s , the attitude transformation matrix is have:

8. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 4, characterized in that: The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the fourth rotation order is positive rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have: The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position C after the fourth rotation order is t s , the attitude transformation matrix is have:

9. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 4, characterized in that: The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the fifth rotation order is positive rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have: The stopping time of the inertial measurement units of the first and second single-axis rotating inertial navigation systems at position D after the fifth rotation order is t s , the attitude transformation matrix is have:

10. The navigation error fusion modulation method for two single-axis rotating inertial navigation systems according to claim 4, characterized in that: The rotation direction of the inertial measurement units of the first and second single-axis rotating inertial navigation systems in the sixth rotation order is positive rotation around the Z axis of the carrier system, and the rotation angular velocity is The rotation angles are all π / 2, and the attitude transformation matrices are all have: The inertial measurement units of the first and second single-axis rotating inertial navigation systems return to position A after the sixth rotation order, and the attitude transformation matrices are both

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