A method for detecting common-mode faults in redundant IRS based on installation location differences

Abstract

This invention proposes a common-mode fault detection method for redundant IRS based on installation position differences, belonging to the field of aviation navigation technology. This method can detect common-mode faults generated by triple-redundant inertial reference systems (IRS) sensors. The principle is based on the characteristics of common-mode faults. By adjusting the installation orientation of the IRS, the angular velocity and acceleration information in the IRS's own coordinate system are projected onto the aircraft's system in opposite directions, amplifying the impact of the common-mode fault on a single axis, thereby achieving monitoring of common-mode faults in the sensor's angular velocity and acceleration information. This scheme is simple in principle, easy to implement, requires no additional redundant hardware modules, and is low in cost.

Description

Technical Field

[0001] This invention relates to the field of civil aviation navigation technology, and in particular to a method for detecting common-mode faults in redundant IRS based on differences in installation location. Background Technology

[0002] An inertial navigation system consists of components such as an inertial measurement unit (IMU), a computer, a chassis, and a bracket. The IMU sensitively detects and outputs the vehicle's acceleration and angular velocity information to calculate navigation parameters such as attitude, heading, velocity, and position. Typically, an IMU contains three orthogonally mounted gyroscopes and accelerometers.

[0003] Currently, most mainstream aircraft models abroad are equipped with triple-redundant inertial reference systems. Since the inertial sensors in a triple-redundant system are indistinguishable, attitude errors can occur due to common-mode faults. Because attitude directly affects flight safety, it is essential to design an attitude fault detection system capable of detecting common-mode faults. Summary of the Invention

[0004] The objective of this invention is to propose a redundant IRS common-mode fault detection method based on installation position differences. By adjusting the installation orientation of the inertial reference system (IRS), the angular velocity and acceleration information in the IRS's own coordinate system are projected onto the aircraft's airframe in opposite directions, amplifying the impact of common-mode faults on a single axis, thereby enabling monitoring of common-mode faults in sensor angular velocity and acceleration information. This solution is simple in principle, easy to implement, requires no redundant hardware modules, and is low in cost.

[0005] The technical solution of this invention is to monitor the angular velocity and acceleration information of the inertial reference system by utilizing different installation positions, thereby ensuring the correctness of the attitude information output of the inertial reference system.

[0006] A method for detecting common-mode faults in redundant IRS based on installation location differences is proposed, including:

[0007] Define a body coordinate system, where b represents the body coordinate system. The coordinate axes of the body coordinate system are fixed to the aircraft body. Select the longitudinal axis of the body along the nose direction as the Y-axis of the b-system. b Positive axis direction, Z b The axis direction is perpendicular to the longitudinal axis of the aircraft, with the upward direction being positive. X b Y b Z b The axis conforms to the right-hand rule;

[0008] Let the s-frame be the coordinate system of the inertial reference system, with its coordinate axes fixed to the sensors in the inertial reference system; the X-axis of the first inertial reference system IRS1 in the triplet inertial reference system... s1 Axis and Xb Reverse axis, Y s1 axis and Y b Axis reversal; X-axis of the second inertial reference system IRS2 s2 Axis and X b The axes are in the same direction, Y s2 axis and Y b The third inertial reference system IRS3 is installed in the same direction as the first inertial reference system IRS1 or the second inertial reference system IRS2.

[0009] In one possible embodiment, the common-mode fault detection method further includes the following steps:

[0010] S1 acquires angular velocity and acceleration information from the gyroscope and accelerometer of the triplet inertial reference system via the bus;

[0011] S2. Based on the angular velocity and acceleration information obtained in step S1, perform a data validity and reasonableness judgment; if the data validity or reasonableness judgment fails, proceed directly to step S6; otherwise, proceed to step S3.

[0012] S3. Based on the angular velocity information output by the triple redundancy inertial reference system, compare it, set the detection threshold, and determine whether a common mode fault occurs in the angular velocity information of each redundancy.

[0013] S4. Based on the acceleration information output by the triple-redundant inertial reference system, compare the results, set the detection threshold, and determine whether the accelerometer has a common-mode fault.

[0014] S5, when either the angular velocity information or the acceleration information exceeds the detection threshold, proceed to step S6;

[0015] S6: Fault information alarm.

[0016] In one possible embodiment, in step S2, the validity of the received angular velocity information and acceleration information is determined based on the valid data bits.

[0017] In one possible embodiment, in step S2, the reasonableness of the received angular velocity and acceleration information is determined based on the aircraft's actual flight maneuverability.

[0018] In one possible embodiment, step 3 specifically includes the following steps:

[0019] S301, Construct the transformation matrix from the s-frame to the b-frame for the first inertial reference system IRS1:

[0020]

[0021] It is easy to know that Let be the transformation matrix from the b-system to the s-system of IRS1;

[0022] S302, Construct the transformation matrix from the s-frame to the b-frame for the second inertial reference system IRS2:

[0023]

[0024] Similarly, Let be the transformation matrix from the b-system to the s-system of IRS2;

[0025] S303, when the gyroscope does not experience a common-mode fault, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 in the s-frame have the following relationship:

[0026]

[0027] Where ω X_theory ω Y_theory ω represents the theoretical value of the angular velocity in the b-system. X_s1 This represents the X-axis angular velocity output of the first inertial reference system IRS1 at time s, ω. Y_s1 This represents the Y-axis angular velocity output of the first inertial reference system IRS1 at time s, ω. X_s2 This represents the X-axis angular velocity output of the second inertial reference system IRS2 at time s, ω. Y_s2 This indicates the Y-axis angular velocity output of the second inertial reference system IRS2 at time s;

[0028] S304, when a gyroscope common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 are respectively

[0029]

[0030] Where, δω err This refers to the angular velocity error caused by the common-mode fault.

[0031] S305 converts the angular velocity information to the machine system's b-system, decoupling the common-mode angular velocity error from the machine system.

[0032]

[0033]

[0034] Replacing the matrix elements with numerical values ​​yields the decoupled numerical equation:

[0035] ω X_b1 =ω X_theory -δω err ω X_b2 =ωX_theory +δω err

[0036] ω Y_b1 =ω Y_theory -δω err ω Y_b2 =ω Y_theory +δω err

[0037] It can be seen that after the IRS is installed in reverse, the common mode angular velocity error is decoupled from the b system angular velocity. The output difference of the two IRS installed in opposite directions under the b system can be used to determine whether an angular velocity common mode fault has occurred.

[0038] S306 utilizes the b-series outputs of two IRSs installed in opposite directions to construct the angular velocity common-mode error detection quantity:

[0039]

[0040] S307, further introducing a third inertial reference system IRS3, when the installation direction of the third inertial reference system is consistent with that of the second inertial reference system IRS2, the transformation matrix from the s-frame to the b-frame of the third inertial reference system IRS3 is:

[0041]

[0042] It can be seen that, This is the transformation matrix from the b-series to the s-series of IRS3;

[0043] S308, when a gyroscope common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the third inertial reference system IRS3 are respectively

[0044]

[0045] Switching to system b, we get

[0046]

[0047] Replacing the matrix elements with numerical values ​​yields the decoupled numerical equation:

[0048] ω X_b1 =ω X_theory -δω err ω X_b3 =ω X_theory +δω err

[0049] ω Y_b1 =ω Y_theory -δω err ω Y_b3 =ωY_theory +δω err

[0050] S309, using the angular velocity outputs in the b-series of two IRSs with the same installation direction, can construct a set of angular velocity common-mode error detection quantities:

[0051]

[0052] S310, when δω err_X =δω err_Y ,δω′ err_X =δω′ err_Y A common-mode fault was detected.

[0053] In one possible embodiment, to avoid false alarms that may be caused by zero bias errors, the fault detection threshold is further increased. ω That is, when δω err_X =δω err_Y ,δω′ err_X =δω′ err_Y And |δω err_X |≥threshold ω1 、|δω′ err_X |≥threshold ω2 If the gyroscopes of the first inertial reference system IRS1, the second inertial reference system IRS2, and the third inertial reference system IRS3 are found to have a common-mode fault, then it is determined that a common-mode fault has occurred.

[0054] In one possible embodiment, step 4 specifically includes the following steps:

[0055] S401, the accelerometers of the first inertial reference system IRS1 and the second inertial reference system IRS2 are installed in the same way as the gyroscopes. When no common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 in the s-frame have the following relationship:

[0056]

[0057] Where a X_theory a Y_theory a represents the theoretical value of acceleration in the b-frame. X_s1 This represents the X-axis acceleration output of the first inertial reference system IRS1 at time s, a Y_s1 This represents the Y-axis acceleration output of the first inertial reference system IRS1 at time s, a X_s2 This represents the X-axis acceleration output of the second inertial reference system IRS2 at time s, a Y_s2 This indicates the Y-axis acceleration output of the second inertial reference system IRS2 at time s;

[0058] S402, when an accelerometer common-mode fault occurs, the acceleration outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 are respectively

[0059]

[0060] Where δa err This refers to the angular velocity error caused by the common-mode fault.

[0061] S403 converts the acceleration information to the machine system b system, obtaining...

[0062]

[0063] Replacing the matrix elements with numerical values ​​yields the numerical equation:

[0064] a X_b1 =a X_theory -δa err a X_b2 =a X_theory +δa err

[0065] a Y_b1 =a Y_theory -δa err a Y_b2 =a Y_theory +δa err

[0066] S404 utilizes the b-series outputs of two IRSs to construct a set of common-mode error detection quantities.

[0067]

[0068] When an accelerometer common-mode fault exists, δa err_X =δa err_Y .

[0069] S405 further introduces a third inertial reference system IRS3, with the installation direction consistent with the second inertial reference system IRS2;

[0070] When an accelerometer common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the third inertial reference system IRS3 are respectively

[0071]

[0072] S406 converts the acceleration information to the machine system b system, obtaining...

[0073]

[0074] S407, replacing the matrix elements with numerical values, yields the numerical equation:

[0075] a X_b1 =a X_theory -δa err a X_b3 =a X_theory +δa err

[0076] a Y_b1 =a Y_theory -δa err a Y_b3 =a Y_theory +δa err

[0077] The S408, utilizing the b-series outputs of two IRSs, can construct a common-mode error detection quantity.

[0078]

[0079] S409, when δa err_X =δa err_Y ,δa′ err_X =δa′ err_Y An accelerometer common-mode fault was detected.

[0080] In one possible embodiment, to avoid false alarms that may be caused by zero bias errors, the fault detection threshold can be further increased. a That is, when δa err_X =δa err_Y ,δa′ err_X =δa′ err_Y And |δa err_X |≥threshold a1 、|δa′ err_X |≥threshold a2 If the accelerometers of the first inertial reference system IRS1, the second inertial reference system IRS2, and the third inertial reference system IRS3 are found to have a common-mode fault, then it is determined that a common-mode fault has occurred in the accelerometers of the third inertial reference system IRS3.

[0081] Beneficial technical effects of the present invention:

[0082] By adjusting the installation orientation of the inertial reference system, the angular velocity and acceleration information in the IRS's own coordinate system are projected onto the aircraft's airframe in opposite directions, amplifying the impact of common-mode faults on a single axis, thereby enabling the monitoring of common-mode faults in sensor angular velocity and acceleration information.

[0083] (1) This invention solves the problem that common-mode faults in redundant inertial navigation systems cannot be detected.

[0084] (2) This invention can locate common-mode faults from the system level to the sensor level and accurately identify common-mode faults in gyroscopes or accelerometers. Attached Figure Description

[0085] To more clearly illustrate the technical solutions implemented in this invention, a simple explanation of the accompanying drawings used in the description of this invention will be provided below. Obviously, the drawings described below are merely some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0086] Figure 1 This is a flowchart illustrating the common-mode fault detection method for redundant IRS based on installation location differences according to the present invention.

[0087] Figure 2 This is a schematic diagram of a common-mode fault detection method for redundant IRS based on installation location differences, according to the present invention. Detailed Implementation

[0088] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0089] The features of various aspects of the embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples. The invention is not limited to any specific setups and methods provided below, but covers all improvements, substitutions, etc., to product structures and methods without departing from the spirit of the invention. In the various drawings and the following description, well-known structures and techniques are not shown to avoid unnecessarily obscuring the invention.

[0090] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0091] The method may include the following steps:

[0092] Step 1: Define the body coordinate system. The b-frame represents the body coordinate system, and its coordinate axes are fixed to the aircraft body. Select the longitudinal axis of the body along the nose direction as the Y-axis of the b-frame. b Positive axis direction, Z b The axis direction is perpendicular to the longitudinal axis of the aircraft, with the upward direction being positive. X b Y b Z b The axis conforms to the right-hand rule, such as Figure 2 As shown;

[0093] Step 2: Select the installation direction of the inertial reference system. Set the s-frame as the coordinate system of the inertial reference system, and fix its coordinate axes to the sensors in the inertial reference system; the X-axis of the first inertial reference system IRS1 in the triple-redundant inertial reference system... s1 Axis and X b Reverse axis, Y s1 axis and Y b Axis reversal; X-axis of the second inertial reference system IRS2 s2 Axis and X b The axes are in the same direction, Y s2 axis and Y b The axes are aligned, and the installation direction of the third inertial reference system IRS3 is the same as that of the first inertial reference system IRS1 or the second inertial reference system IRS2.

[0094] Step 3: Obtain the angular velocity and acceleration information output by the gyroscope and accelerometer of the triple-redundant inertial reference system via the bus;

[0095] Step 4: After each IRS receives data, it first performs a validity check. The validity of the data is determined according to the valid bits specified in the bus data protocol. If the data is valid, its reasonableness is checked; otherwise, the data for the current frame is considered unusable, and the system waits for the next frame. The reasonableness of the data is judged based on the actual maneuverability of the civil aircraft. The change in angular velocity over a continuous period should not exceed a set threshold, preferably 5° / s, and the change in angular velocity over a continuous period should not exceed a set threshold, preferably 3m / s. 2 If the difference between the current angular velocity and acceleration and the previous angular velocity and acceleration exceeds the threshold, the data is considered unreasonable, the system issues an alarm, and the process ends.

[0096] Step 5: Compare the angular velocity information output by the triple redundancy IRS, set the detection threshold, and determine whether a common-mode fault occurs in the angular velocity information.

[0097] Construct the transformation matrix from the s-frame to the b-frame for the first inertial reference system IRS1:

[0098]

[0099] It is easy to know that Let be the transformation matrix from the b-series to the s-series of IRS1.

[0100] Construct the transformation matrix from the s-frame to the b-frame for the second inertial reference system IRS2:

[0101]

[0102] Similarly, This is the transformation matrix from the b-series to the s-series of IRS2.

[0103] When no common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 in the s-frame have the following relationship:

[0104]

[0105] Where ω X_theory ω Y_theory ω represents the theoretical value of the angular velocity in the b-system. X_s1 This represents the X-axis angular velocity output of the first inertial reference system IRS1 at time s, ω. Y_s1 This represents the Y-axis angular velocity output of the first inertial reference system IRS1 at time s, ω. X_s2 This represents the X-axis angular velocity output of the second inertial reference system IRS2 at time s, ω. Y_s2 This indicates the Y-axis angular velocity output of the second inertial reference system IRS2 at time s.

[0106] When a gyroscope common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 are respectively

[0107]

[0108] Where δω err This refers to the angular velocity error caused by the common-mode fault.

[0109] Convert the angular velocity information to the machine system's b-system to decouple the common-mode angular velocity error from the machine system:

[0110]

[0111] Replacing the matrix elements with numerical values ​​yields the decoupled numerical equation:

[0112] ω X_b1 =ω X_theory -δω err ω X_b2 =ω X_theory +δω err

[0113] ω Y_b1 =ωY_theory -δω err ω Y_b2 =ω Y_theory +δω err

[0114] Therefore, after the IRS is installed in reverse, the common-mode angular velocity error is decoupled from the b-system. The output difference between the two IRSs in the b-system can be used to determine whether a common-mode angular velocity fault has occurred.

[0115] Using the b-series outputs of two IRS sets, the common-mode error of angular velocity can be constructed:

[0116]

[0117] Furthermore, a third inertial reference system, IRS3, is introduced. When the installation direction of the third inertial reference system is the same as that of the second inertial reference system, IRS2, the transformation matrix from the s-frame to the b-frame of the third inertial reference system, IRS3, is:

[0118]

[0119] It can be seen that, This is the transformation matrix from the b-series to the s-series of IRS3.

[0120] When a gyroscope common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the third inertial reference system IRS3 are respectively

[0121]

[0122] Switching to system b, we get

[0123]

[0124] Replacing the matrix elements with numerical values ​​yields the decoupled numerical equation:

[0125] ω X_b1 =ω X_theory -δω err ω X_b3 =ω X_theory +δω err

[0126] ω Y_b1 =ω Y_theory -δω err ω Y_b3 =ω Y_theory +δω err

[0127] By utilizing the angular velocity outputs in the b-series of two IRSs with the same installation orientation, a set of angular velocity common-mode error detection quantities can be constructed:

[0128]

[0129] When a gyroscope common-mode fault exists, δω err_X =δω err_Y ,δω′ err_X =δω′ err_Y Meanwhile, to avoid false alarms that may be caused by zero bias errors, the fault detection threshold is further increased. ω That is, when δω err_X =δω err_Y ,δω′ err_X =δω′ err_Y And |δω err_X |≥threshold ω1 、|δω′ err_X |≥threshold ω2 If a common-mode fault occurs in the gyroscopes of the first inertial reference system IRS1, the second inertial reference system IRS2, and the third inertial reference system IRS3, an alarm is triggered, and the process ends; otherwise, proceed to step 6.

[0130] Step 6: Compare the acceleration information output by the triple redundancy IRS, set the detection threshold, and determine whether the accelerometer has a common-mode fault.

[0131] The accelerometers of the first inertial reference system IRS1 and the second inertial reference system IRS2 are installed in the same way as the gyroscopes. When no common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 in the s-frame have the following relationship:

[0132]

[0133] Where a X_theory a Y_theory a represents the theoretical value of acceleration in the b-frame. X_s1 This represents the X-axis acceleration output of the first inertial reference system IRS1 at time s, a Y_s1 This represents the Y-axis acceleration output of the first inertial reference system IRS1 at time s, a X_s2 This represents the X-axis acceleration output of the second inertial reference system IRS2 at time s, a Y_s2 This indicates the Y-axis acceleration output of the second inertial reference system IRS2 at time s.

[0134] When an accelerometer common-mode fault occurs, the acceleration outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 are respectively

[0135]

[0136] Where δa err This refers to the angular velocity error caused by the common-mode fault.

[0137] The acceleration information is converted to the machine system b system to obtain...

[0138]

[0139] Replacing the matrix elements with numerical values ​​yields the numerical equation:

[0140] a X_b1 =a X_theory -δa err a X_b2 =a X_theory +δa err

[0141] a Y_b1 =a Y_theory -δa err a Y_b2 =a Y_theory +δa err

[0142] By utilizing the b-series outputs of two IRS sets, a common-mode error detection quantity can be constructed.

[0143]

[0144] When an accelerometer common-mode fault exists, δa err_X =δa err_Y .

[0145] A third inertial reference system, IRS3, is further introduced, with its installation direction consistent with that of the second inertial reference system, IRS2.

[0146] When an accelerometer common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the third inertial reference system IRS3 are respectively

[0147]

[0148] The acceleration information is converted to the machine system b system to obtain...

[0149]

[0150] Replacing the matrix elements with numerical values ​​yields the numerical equation:

[0151] a X_b1 =a X_theory -δa err a X_b3 =a X_theory +δa err

[0152] a Y_b1 =a Y_theory -δa err a Y_b3 =a Y_theory +δa err

[0153] Using the b-series outputs of two IRS sets, a set of common-mode error detection quantities can be constructed.

[0154]

[0155] When an accelerometer common-mode fault exists, δa err_X =δa err_Y ,δa′ err_X =δa′ err_Y Meanwhile, to avoid false alarms that may be caused by zero bias errors, the fault detection threshold can be further increased. a That is, when δa err_X =δa err_Y ,δa′ err_X =δa′ err_Y And |δa err_X |≥threshold a1 、|δa′ err_X |≥threshold a2 If a common-mode fault occurs in the accelerometers of the first inertial reference system IRS1, the second inertial reference system IRS2, and the third inertial reference system IRS3, the system will issue an alarm.

[0156] Step 7, fault information alarm: When either the angular velocity information or the acceleration information exceeds the detection threshold, the system sends out an alarm message and the process ends.

[0157] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for detecting common-mode faults in redundant IRS based on installation location differences, characterized in that, include: Define a body coordinate system, where b represents the body coordinate system. The coordinate axes of the body coordinate system are fixed to the aircraft body. Select the longitudinal axis of the body along the nose direction as the Y-axis of the b-system. b Positive axis direction, Z b The axis direction is perpendicular to the longitudinal axis of the aircraft, with the upward direction being positive. X b Y b Z b The axes conform to the right-hand rule; the s-frame is defined as the coordinate system of the inertial reference system, and its coordinate axes are fixed to the sensors in the inertial reference system; the X-axis of the first inertial reference system IRS1 in the triple-redundant inertial reference system... s1 Axis and X b Reverse axis, Y s1 axis and Y b Axis reversal; X-axis of the second inertial reference system IRS2 s2 Axis and X b The axes are in the same direction, Y s2 axis and Y b The common-mode fault detection method further includes the following steps: S1, acquiring angular velocity and acceleration information output by the gyroscope and accelerometer of the triple-redundant inertial reference system via the bus; S2, judging the validity and rationality of the data based on the angular velocity and acceleration information acquired in step S1; if the data validity or rationality judgment is not passed, proceed directly to step S6; otherwise, proceed to step S3. S3. Based on the angular velocity information output by the triple redundancy inertial reference system, compare it, set the detection threshold, and determine whether a common mode fault occurs in the angular velocity information of each redundancy. S4. Compare the acceleration information output by the triple-redundant inertial reference system, set a detection threshold, and determine whether the accelerometer has a common-mode fault; S5. When either the angular velocity information or the acceleration information exceeds the detection threshold, proceed to step S6. S6 Fault information alarm; In step S2, the validity of the received angular velocity and acceleration information is determined based on the valid data bits; in step S2, the reasonableness of the received angular velocity and acceleration information is determined based on the actual flight maneuverability of the aircraft.

2. The method for detecting common-mode faults in redundant IRS based on installation location differences according to claim 1, characterized in that, Step S3 specifically includes the following steps: S301, Construct the transformation matrix from the s-frame to the b-frame for the first inertial reference system IRS1: It is easy to know that , Let be the transformation matrix from the b-system to the s-system of IRS1; S302, Construct the transformation matrix from the s-frame to the b-frame for the second inertial reference system IRS2: Similarly, , Let be the transformation matrix from the b-system to the s-system of IRS2; S303, when the gyroscope does not experience a common-mode fault, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 in the s-frame have the following relationship: ， ， in , This represents the theoretical value of the angular velocity in the b-system. This represents the X-axis angular velocity output of the first inertial reference system IRS1 at time s. This represents the Y-axis angular velocity output of the first inertial reference system IRS1 at time s. This indicates the X-axis angular velocity output of the second inertial reference system IRS2 at time s. This indicates the Y-axis angular velocity output of the second inertial reference system IRS2 at time s; S304, when a gyroscope common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 are respectively ， ， in, This refers to the angular velocity error caused by the common-mode fault. S305 converts the angular velocity information to the machine system's b-system, decoupling the common-mode angular velocity error from the machine system. Replacing the matrix elements with numerical values ​​yields the decoupled numerical equation: ， ， It can be seen that after the IRS is installed in reverse, the common mode angular velocity error is decoupled from the b system angular velocity. The output difference of the two IRS installed in opposite directions under the b system can be used to determine whether an angular velocity common mode fault has occurred. S306 utilizes the b-series outputs of two IRSs installed in opposite directions to construct the angular velocity common-mode error detection quantity: ， S307, further introducing a third inertial reference system IRS3, when the installation direction of the third inertial reference system is consistent with that of the second inertial reference system IRS2, the transformation matrix from the s-frame to the b-frame of the third inertial reference system IRS3 is: It can be seen that, , This is the transformation matrix from the b-series to the s-series of IRS3; S308, when a gyroscope common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the third inertial reference system IRS3 are respectively ， ， Switching to system b, we get Replacing the matrix elements with numerical values ​​yields the decoupled numerical equation: ， ， S309, using the angular velocity outputs in the b-series of two IRSs with the same installation direction, can construct a set of angular velocity common-mode error detection quantities: ， S310, when , A common-mode fault was detected.

3. The method for detecting common-mode faults in redundant IRS based on installation location differences according to claim 1, characterized in that, Set fault detection thresholds That is, when , and , If the gyroscopes of the first inertial reference system IRS1, the second inertial reference system IRS2, and the third inertial reference system IRS3 are found to have a common-mode fault, then it is determined that a common-mode fault has occurred.

4. The method for detecting common-mode faults in redundant IRS based on installation location differences according to claim 1, characterized in that, Step S4 specifically includes the following steps: S401, the installation method of the accelerometers of the first inertial reference system IRS1 and the second inertial reference system IRS2 is the same as that of the gyroscope; When no common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 in the s-frame have the following relationship: ， ， in , This represents the theoretical value of acceleration in the b-frame. This represents the X-axis acceleration output of the first inertial reference system IRS1 at time s. This represents the Y-axis acceleration output of the first inertial reference system IRS1 at time s. This indicates the X-axis acceleration output of the second inertial reference system IRS2 at time s. This indicates the Y-axis acceleration output of the second inertial reference system IRS2 at time s; S402, when an accelerometer common-mode fault occurs, the acceleration outputs of the first inertial reference system IRS1 and the second inertial reference system IRS2 are respectively ， ， in This refers to the angular velocity error caused by the common-mode fault. S403 converts the acceleration information to the machine system b system, obtaining... Replacing the matrix elements with numerical values ​​yields the numerical equation: ， ， S404 utilizes the b-series outputs of two IRSs to construct a set of common-mode error detection quantities. ， When an accelerometer common-mode fault exists ; S405 further introduces a third inertial reference system IRS3, with the installation direction consistent with the second inertial reference system IRS2; When an accelerometer common-mode fault occurs, the outputs of the first inertial reference system IRS1 and the third inertial reference system IRS3 are respectively ， ， S406 converts the acceleration information to the machine system b system, obtaining... S407, replacing the matrix elements with numerical values, yields the numerical equation: ， ， The S408, utilizing the b-series outputs of two IRSs, can construct a common-mode error detection quantity. ， S409, when , An accelerometer common-mode fault was detected.

5. The method for detecting common-mode faults in redundant IRS based on installation location differences according to claim 1, characterized in that, Set fault detection thresholds That is, when , and , If the accelerometers of the first inertial reference system IRS1, the second inertial reference system IRS2, and the third inertial reference system IRS3 are found to have a common-mode fault, then it is determined that a common-mode fault has occurred in the accelerometers of the third inertial reference system IRS3.

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