A method for detecting faults in an inertial navigation device based on a laser gyroscope

Abstract

The application relates to the technical field of inertial navigation, in particular to a fault detection method of an inertial navigation device based on a laser gyroscope, which comprises the following steps: (1) giving all possible fault states of the laser inertial navigation and fault detection contents; (2) starting self-checking of the device; (3) initial alignment; (4) pure inertial navigation detection; (5) DVL speed combined navigation detection; and (6) satellite position combined navigation detection. The application detects the device-level faults of the laser gyroscope and the accelerometer and detects the system faults of the navigation device, improves the self-checking efficiency of the device, and further improves the performance of the inertial navigation and the reliability of the navigation.

Description

Technical Field

[0001] This invention relates to the field of inertial navigation technology, specifically to a fault detection method for inertial navigation equipment based on a laser gyroscope. Background Technology

[0002] Laser gyroscopes and fiber optic gyroscopes are both next-generation inertial sensors that utilize the Sagnac effect of light to measure angular velocity, but their optical paths differ significantly. The optical path of a laser gyroscope is a fixed glass cavity. Angular velocity is obtained by measuring the frequency difference between two non-reciprocal laser beams within the cavity. Because the laser optical path is short and operates in a vacuum, the sensitive loop structure is stable and less affected by external stresses such as temperature. The optical path of a fiber optic gyroscope is constructed from thousands of meters of fiber optic cable. Any change in the optical path caused by environmental factors such as vibration, temperature, humidity, and air pressure will introduce measurement errors. Furthermore, since the fiber optic loops are bonded with epoxy resin, the aging and deformation of the resin over long-term use alters the zero bias and scale factor of the fiber optic gyroscope, ultimately leading to a decrease in system accuracy. Therefore, although laser gyroscopes and fiber optic gyroscopes operate on the same principle, the former has significant advantages over the latter in terms of long-term stability and environmental adaptability.

[0003] Currently, with the development of laser inertial navigation technology, the advantages of laser inertial navigation have been further developed, and various laser inertial navigation systems are now being mass-produced and deployed in land, sea, air, and civilian fields. To improve the user experience of laser inertial navigation and reduce product maintenance costs, it is necessary to improve the self-testing efficiency of the equipment, from device-level fault detection of laser gyroscopes and accelerometers to system fault detection of navigation devices, thereby further enhancing the performance and reliability of inertial navigation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a fault detection method for inertial navigation equipment based on laser gyroscopes, (1) real-time fault judgment is performed on the monitoring information of laser gyroscopes and quartz flexible accelerometers, and the user is notified in real time when a fault occurs; (2) during alignment and navigation, the effectiveness of satellite navigation information and Doppler information is judged in real time using external satellite navigation information and Doppler information, and at the same time, the navigation information and Kalman filter parameters during the alignment and navigation process of the inertial navigation system are detected in real time, and the effectiveness of the inertial navigation alignment and navigation process is reported in real time; (3) the working status of laser inertial navigation is provided in real time, reducing manual maintenance costs.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a fault detection method for inertial navigation equipment based on a laser gyroscope, comprising the following steps:

[0006] (1) All possible fault states and fault detection contents of laser inertial navigation are given. The fault state detection methods are different at different stages. At the same time, the fault detection contents under different working conditions are given. The specific detection methods are given later according to different fault detection contents.

[0007] (2) The equipment performs a self-test upon startup, which mainly includes hardware initialization, parameter initialization, and inertial device testing.

[0008] (3) Initial alignment, the main inspection contents include satellite guidance effectiveness, alignment process effectiveness and system error monitoring;

[0009] (4) Pure inertial navigation detection, the main detection contents include the effectiveness of navigation information and the real-time status of the carrier;

[0010] (5) DVL speed integrated navigation detection, the main detection contents include Doppler measurement information, speed integrated navigation status and navigation performance estimation;

[0011] (6) Satellite position integrated navigation detection, the detection content mainly includes satellite measurement information, position integrated navigation status and navigation performance estimation.

[0012] In some embodiments, according to step (2),

[0013] In the hardware initialization test, first check whether the navigation computer starts up normally; second, check whether the power supply voltage and current of the power module, IF conversion module and inertial device are normal; and finally, check whether the navigation computer's external interface initialization is normal.

[0014] In the parameter initialization test, firstly, it checks whether the system navigation parameters saved by the hardware are normal. Secondly, it checks the system temperature and completes the configuration of temperature model-related parameters such as laser gyroscope and accelerometer. Finally, it completes the initialization of alignment-related parameters, including alignment time, number of iterative alignments, and initialization of Kalman filter parameters, to see if they are within the specified range.

[0015] In inertial device testing, the laser gyroscope, quartz flexural accelerometer, and temperature parameters in the laser gyroscope inertial navigation device are read in real time.

[0016] In some embodiments, the inertial device detection method is as follows:

[0017] 1) Data validity assessment,

[0018] First, calculate the magnitude of the laser gyroscope and accelerometer data, ensuring the values ​​are within the specified threshold range. Then, calculate the range and volatility of the gyroscope and accelerometer data, also within the corresponding threshold range. Finally, calculate the combined angular velocity and acceleration of the laser gyroscope and accelerometer data. Under static conditions, these values ​​should be essentially consistent with the Earth's rotation angular velocity and gravitational acceleration; under dynamic conditions, they should be within the corresponding threshold range. Apply these evaluation methods to check whether the measured values ​​are normal.

[0019] 2) Judgment based on monitoring data,

[0020] First, the laser gyroscope's light intensity, amplitude, frequency, and anode / cathode temperatures are received in real time to monitor its operational status. If the readings are outside the corresponding monitoring thresholds, the device is considered to be malfunctioning. Second, the accelerometer temperature is received in real time and compared with the laser gyroscope temperature. The temperature difference and rate of temperature change should be within the corresponding threshold ranges. Finally, the high-precision IF clock crystal oscillator is detected in real time, and it should be within a certain error range compared with the local computer crystal oscillator.

[0021] In some embodiments, according to step (3),

[0022] The satellite navigation validity detection process involves the following steps: After the equipment meets the initial alignment conditions, it receives navigation data from the satellite navigation system in real time. First, it checks the continuity of the data. If there is continuous data inconsistency or no data for more than 2 seconds, the satellite navigation data is considered to have poor continuity. If there is more than 30 seconds of invalid data within one minute, the system reports that the inertial navigation system does not meet the initial alignment conditions. Second, it unpacks the satellite navigation data packet protocol content, including the satellite navigation validity and HDR value, to determine if the satellite navigation is valid and meets the application conditions for inertial navigation initial alignment. Then, it evaluates the received satellite navigation latitude, longitude, altitude, and speed information. Using the relationship between speed, trajectory, and latitude and longitude, it determines whether the carrier is stationary or moving. Under stationary or moving conditions, it assesses the fluctuation of latitude, longitude, and speed data. If the fluctuation exceeds a predetermined threshold range, the satellite navigation positioning is considered abnormal. Finally, during the initial alignment process, it continuously assesses the correlation characteristics between the satellite navigation speed and latitude / longitude and the latitude, longitude, and speed information output during the inertial navigation initial alignment process to determine if the satellite navigation is within the corresponding threshold range.

[0023] The effectiveness detection of the alignment process involves several steps. First, after continuously receiving valid satellite navigation data for 30 seconds, the device automatically begins the initial alignment process. For the first 100 seconds, dynamic analytical alignment is completed. After alignment, the device enters Kalman filter integrated navigation alignment. Second, during the initial alignment process, the effectiveness of the satellite navigation is monitored in real time. If invalid satellite navigation data occurs continuously for one minute, an initial alignment failure is indicated in the initial alignment status. Then, the initial alignment requires the platform to be either stationary or in uniform linear motion. Inertial devices and satellite navigation data are used to determine the platform's state. During the analytical alignment process, changes in satellite navigation trajectory and speed are analyzed. If both the device's speed and trajectory changes simultaneously exceed a specified threshold, the alignment is corrected. The equipment stops initial alignment, reports an abnormality in the initial alignment process, and indicates alignment failure. Then, within 240 seconds before the end of the initial alignment, it detects changes in the inertial navigation heading. If the heading change is greater than 45 degrees, it reports an abnormality in the initial alignment maneuver and a decrease in alignment performance. Finally, it judges the position, velocity, heading, and attitude output by the inertial navigation system in real time. The position error should be less than 5 meters from the latitude and longitude error of the satellite navigation system, and the velocity error should be less than 0.1 knots. During uniform straight-line alignment, the rate of change of heading and the value of heading change should not exceed 1 degree per second and 90 degrees, respectively, and the attitude change should be less than 10 degrees. During stationary alignment, the rate of change of heading and the value of heading change should not exceed 0.1 degrees per second and 3 degrees, respectively, and the attitude change should be less than 1 degree.

[0024] System error monitoring involves several steps. First, real-time assessment of speed and heading errors during alignment. The speed error change in the northeast direction should be less than 0.002 m / s, and the heading error change should be less than 0.001° / s. Second, real-time assessment of system error estimation during the initial alignment process. During static alignment, the estimated speed error should not exceed 2 knots, and the heading error should not exceed 0.2 degrees. During uniform straight-line alignment, the estimated speed error should not exceed 4 knots, and the heading error should not exceed 1.0 degree. If these thresholds are exceeded, an abnormal system error estimation is reported. Third, real-time assessment of inertial device constant bias during alignment. The laser gyroscope bias should not exceed 0.1 degrees / hour, and the accelerometer constant bias should not exceed 500 μg. If these thresholds are exceeded, an inertial device output anomaly is reported. Finally, 30 seconds before the end of alignment, real-time detection of inertial device estimated bias is performed. The laser gyroscope bias should not exceed 0.02 degrees / hour, and the accelerometer constant bias should not exceed 200 μg. If these thresholds are exceeded, an inertial device output anomaly is reported.

[0025] In some embodiments, according to step (4),

[0026] The effectiveness of navigation information is first determined by assessing the vehicle's speed in real time, based on the vehicle's maximum speed V. max Given an inertial navigation velocity error of 1 m / s, and assuming the pure inertial navigation time is t, the inertial navigation velocity threshold is defined as V = Vmax +1.0t, real-time judgment of carrier speed. If the speed exceeds this value, the navigation speed accuracy is abnormal. If it exceeds twice the threshold, the navigation accuracy fault is directly output. Secondly, the angular velocity of the carrier is judged. The angular velocities in three directions are judged. If they exceed the specified threshold, the carrier angular velocity is abnormal. If it exceeds the maximum gyroscope angular velocity of 400° / s, the inertial navigation angular velocity fault is output.

[0027] The carrier's real-time status is determined first by judging the carrier's heading and attitude information in real time. The attitude information should be within a certain range. If it exceeds the specified value, an attitude anomaly is output. Second, the output latitude and longitude position information is judged. Based on the carrier's motion speed V and inertial navigation speed error δV, assuming the initial latitude and longitude are L0 and λ0 respectively, and the pure inertial navigation time is t, the latitude and longitude position range of the carrier is calculated. If the position range is exceeded, the position information is sent as an anomaly.

[0028] In some embodiments, taking the latitude calculation formula as an example, the calculation method is as follows:

[0029] L=L0+(V max +δV)t / R

[0030] R is the Earth's radius.

[0031] In some embodiments, according to step (5),

[0032] The process for obtaining Doppler measurement information involves several steps. First, Doppler measurement information is received in real time, and the interval between two adjacent sets of Doppler information is calculated. If the Doppler interval exceeds 2 seconds, the Doppler velocity data is considered discontinuous; if it lasts for more than 10 seconds, the discontinuity is reported. Second, the validity flag of the Doppler velocity message is used to determine whether the Doppler velocity is valid, and this information is sent in real time. Then, the validity of the Doppler velocity is assessed in real time to determine whether the velocity information can be used for velocity-based navigation.

[0033] The velocity-integrated navigation status detection process is as follows: First, if the Doppler bottom alignment velocity is valid and the bottom alignment depth is within the Doppler bottom alignment depth range, inertial navigation and Doppler are used for velocity-integrated navigation. The validity of the Doppler is assessed in real time. If the Doppler is invalid, the velocity-integrated navigation is terminated immediately, and Kalman filtering prediction is performed. Second, the pure inertial navigation latitude and longitude errors are detected in real time. These errors should meet the pure inertial navigation positioning accuracy requirements. When the positioning error is greater than the nominal inertial navigation error but less than twice the nominal value, a combined navigation warning is sent. If the navigation error is greater than twice the nominal inertial navigation positioning error, an inertial navigation positioning accuracy anomaly is reported. Then, under normal combined navigation conditions, if the Doppler velocity is invalid for 5 consecutive minutes, a decrease in Doppler combined navigation accuracy is reported. If this exceeds half an hour, the inertial navigation is reported to be operating in pure inertial navigation mode. When the Doppler velocity becomes valid again, the velocity combination is reported as valid, requiring satellite navigation to perform position calibration to improve the performance of the combined navigation data. Finally, if combined navigation operates continuously for 5 hours, the combined navigation accuracy is reported to require satellite navigation calibration.

[0034] Navigation performance estimation involves several steps. First, using the latitude and longitude errors estimated by the velocity-integrated navigation system, the pure inertial navigation accuracy is calculated in real time. If the positioning error is less than twice the nominal value, the navigation accuracy is reported as normal; otherwise, a decrease in pure inertial navigation performance is reported. Second, the pure inertial navigation velocity error is calculated in real time. When the velocity error is greater than twice the nominal value, satellite navigation calibration is required, and heading and attitude errors are monitored in real time. Third, the errors of the inertial navigation devices are detected. The zero bias of the laser gyroscope and the constant zero bias of the accelerometer should be within the specified threshold range. If the error exceeds the threshold range, an abnormality in the inertial device error is reported based on the integrated navigation accuracy.

[0035] In some embodiments, the determination of whether Doppler velocity is suitable for velocity-integrated navigation is performed as follows:

[0036] 1) Speed ​​range judgment: The speed obtained by unpacking should be within the effective Doppler speed measurement range. The speed measurement value should be less than the maximum heading speed of the carrier. In addition, the speed value should be within a certain error range of the inertial navigation speed. If the speed is valid, the speed can be combined.

[0037] 2) Speed ​​stability judgment: continuously save more than 3 sets of real-time continuous speed information, calculate their range. If the range is less than the specified range threshold, the speed measurement value is considered valid and can be used for speed combination navigation.

[0038] 3) Acceleration judgment: The effective velocity of Doppler is saved in real time and looped. The acceleration information of the carrier is obtained by subtracting the current velocity from the velocity at the previous moment. The acceleration information is compared with the acceleration information calculated by the inertial navigation system. The error should be less than the specified threshold. Otherwise, the Doppler velocity is judged to be invalid.

[0039] 4) Vehicle maneuverability assessment: Real-time measurement of the vehicle's heading angular rate and attitude angular velocity. The measured values ​​should be within the corresponding threshold range to ensure that Doppler velocity measurement is real-time and accurate.

[0040] If the above four criteria are met, Doppler velocity can be combined with inertial navigation for velocity-integrated navigation.

[0041] In some embodiments, according to step (6), the satellite measurement information is firstly received continuously, and when the satellite navigation information is discontinuous, the satellite navigation information packet loss is reported; secondly, the validity and positioning factor of the satellite navigation are decrypted to determine the validity of the satellite navigation information; then, the inertial navigation information is used to determine whether the undetermined navigation information is valid.

[0042] The position-integrated navigation status detection process involves several steps. First, the validity of satellite navigation information is assessed. If the position information is valid, inertial navigation (INS) and satellite navigation information are combined for position-integrated navigation, with the validity of satellite navigation being assessed in real time. If satellite navigation is invalid, position-integrated navigation is discontinued, and Kalman filtering prediction is performed. Second, the pure INS latitude and longitude errors of the position-integrated navigation are detected in real time. The latitude and longitude errors should meet the pure INS positioning accuracy requirements. When the positioning error is greater than the nominal value of the INS positioning error but less than twice the nominal value, a pure INS positioning warning is sent. If the navigation error is greater than twice the nominal value of the INS positioning error, an INS positioning accuracy out-of-tolerance warning is sent. Then, under normal integrated navigation conditions, if the satellite position is invalid for 5 consecutive minutes, a decrease in position-integrated navigation accuracy is reported. If this exceeds half an hour, the INS is reported to be operating in pure INS navigation mode. When the satellite navigation accuracy is valid again, the position combination is reported to be valid. Finally, after 5 hours of continuous integrated navigation operation, closed-loop calibration of system errors and inertial device errors is performed.

[0043] Navigation performance estimation involves several steps. First, using the latitude and longitude errors estimated by the velocity-integrated navigation system, the pure inertial navigation accuracy is calculated in real time. If the positioning error is less than twice the nominal value, the navigation accuracy is reported as normal; otherwise, a decrease in pure inertial navigation performance is reported. Second, the pure inertial navigation velocity error is calculated in real time. When the velocity error is greater than twice the nominal value, satellite navigation calibration is required, and heading and attitude errors are monitored in real time. Third, the errors of the inertial navigation devices are detected. The zero bias of the laser gyroscope and the constant zero bias of the accelerometer should be within the specified threshold range. If the error exceeds the threshold range, an abnormality in the inertial device error is reported based on the integrated navigation accuracy.

[0044] In some embodiments, the method for determining the validity of undetermined navigation information using inertial navigation information is as follows:

[0045] 1) Speed ​​and position range judgment: The speed obtained from unpacking should be less than the maximum heading speed of the carrier. In addition, the speed value should be within a certain error range from the inertial navigation speed. The speed is considered valid. At the same time, the inertial navigation position error calculated by applying satellite navigation should be within a certain threshold range. The satellite navigation is considered valid.

[0046] 2) Position stability judgment: continuously save more than 3 sets of real-time continuous position information, calculate their range. If the range is less than the specified range threshold, the position measurement value is considered valid and can be used for position combination navigation.

[0047] 3) Position difference judgment: The effective latitude and longitude of satellite navigation are saved in real time. The difference between the current latitude and longitude and the latitude and longitude at the previous moment is used to obtain the velocity information of the vehicle. This information is compared with the velocity information calculated by the inertial navigation system. The error should be less than the specified threshold. Otherwise, the satellite navigation position information is judged to be invalid.

[0048] If the above three criteria are met, satellite navigation position information can be combined with inertial navigation for position-integrated navigation.

[0049] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention comprehensively utilizes multiple types of navigation information, such as inertial navigation, satellite navigation, and Doppler, to complete fault information judgment in the standby, alignment, and navigation stages. In the standby stage, it mainly completes self-checks and fault alarms for inertial devices and inertial navigation equipment initialization information; in the initial alignment stage, it mainly completes the validity of satellite navigation information, the initial alignment performance of inertial navigation, and the fault cause analysis of alignment failures; in the navigation stage, it utilizes the inherent relevant parameters of the carrier to complete fault judgments for navigation parameter data such as pure inertial navigation information and combined navigation information, significantly improving the equipment's self-checking capabilities, reducing manual data analysis, and enhancing the platform's application friendliness and user experience.

[0050] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. The embodiments of this application will provide a detailed description and understanding of the application. Attached Figure Description

[0051] Figure 1 This is a diagram illustrating the fault detection functionality of the inertial navigation device according to the present invention.

[0052] Figure 2 This is a flowchart of the inertial navigation device fault detection method of the present invention. Detailed Implementation

[0053] 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 embodiments of the present invention, and not all embodiments. 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.

[0054] The laser gyroscope inertial navigation system mainly consists of three laser gyroscopes, three quartz flexural accelerometers, an IF conversion module, a navigation computer, and a power supply module. The navigation computer, a dual-core processor, is the navigation calculation module. Employing an embedded system without an operating system to ensure real-time data processing, it comprises a preprocessing module and a navigation calculation module. The preprocessing module primarily handles the acquisition, processing, and output of raw data from the inertial devices, while the navigation calculation module performs initial alignment, navigation calculation, and external interface functions. During operation, the navigation computer's navigation calculation module receives satellite (GPS, BeiDou, etc.) navigation information, performs initial alignment and integrated navigation, and outputs high-precision position, velocity, and attitude information. When satellite navigation information is invalid, it integrates with Doppler velocimetry for velocity-integrated navigation; when Doppler velocity is invalid, it performs pure inertial navigation. From power-on self-test to navigation operation, the inertial navigation system performs real-time self-tests, sending the self-test information to external users via a communication protocol, improving the reliability of equipment information and facilitating equipment maintenance and use.

[0055] This invention provides a technical solution: a fault detection method for inertial navigation equipment based on a laser gyroscope, comprising the following steps:

[0056] Step (1) gives all possible fault states and fault detection contents of laser inertial navigation. The fault state detection methods are different at different stages. At the same time, the fault detection contents under different working states are given. The specific detection methods are given later according to different fault detection contents.

[0057] like Figure 1 As shown, all possible fault states of laser inertial navigation and their detection methods are presented. The detection methods vary depending on the stage of the fault state. Figure 2 The fault detection content is given under different working conditions, and the specific detection methods are given according to different fault detection content.

[0058] In the hardware initialization test, the first step is to check whether the navigation computer starts up normally. The second step is to check whether the power supply voltage and current of the power module, IF conversion module and inertial devices are normal. Finally, the third step is to check whether the navigation computer's external interface is initialized normally.

[0059] In the parameter initialization test, the system navigation parameters stored in the hardware are first checked to see if they are normal. Then, the system temperature is checked and the relevant parameters of the temperature model such as the laser gyroscope and accelerometer are configured. Finally, the initial alignment-related parameters are initialized, including alignment time, number of iterative alignments, and initial Kalman filter parameters, to see if they are within the specified range.

[0060] In inertial device testing, the parameters of three laser gyroscopes, three quartz flexural accelerometers, and temperature are read in real time.

[0061] First, the validity of the data is determined by calculating the magnitude of the laser gyroscope and accelerometer data, which should be within the specified threshold range. Then, the range (difference between the maximum and minimum values) and volatility (1-second variance) of the gyroscope and accelerometer data are calculated, and these should also be within the corresponding threshold range. Finally, the combined angular velocity and acceleration of the three gyroscopes and accelerometers are calculated separately. Under static conditions, these values ​​should be basically consistent with the Earth's rotation angular velocity and gravitational acceleration; under dynamic conditions, they should be within the corresponding threshold range (the relevant threshold parameters are set according to the application scenario of the carrier). These evaluation methods are used to check whether the measured values ​​are normal.

[0062] Second, the monitoring data is used for judgment. First, the light intensity, amplitude, frequency, and anode and cathode temperatures of the three laser gyroscopes are received in real time to monitor whether the laser gyroscopes are working normally. If they are not within the corresponding monitoring thresholds, the equipment is considered to be malfunctioning. Second, the accelerometer temperature is received in real time and compared with the laser gyroscope temperature. The temperature difference and the rate of temperature change should be within the corresponding threshold range. Finally, the high-precision clock crystal oscillator of the IF sensor is detected in real time. It should be within a certain error range compared with the local computer crystal oscillator.

[0063] Step (3), initial alignment, mainly includes the effectiveness of satellite guidance, the effectiveness of the alignment process and the monitoring of system errors.

[0064] The satellite navigation validity detection process involves the following steps: After the equipment meets the initial alignment conditions, it receives navigation data from the satellite navigation system in real time. First, it checks the continuity of the data. If there is continuous data inconsistency or no data for more than 2 seconds, the satellite navigation data is considered to have poor continuity. If there is more than 30 seconds of invalid data within one minute, the system reports that the inertial navigation system does not meet the initial alignment conditions. Second, it unpacks the satellite navigation data packet protocol content, including the satellite navigation validity and HDR value, to roughly determine whether the satellite navigation is valid and meets the application conditions for initial inertial navigation alignment. Then, it evaluates the received satellite navigation latitude, longitude, altitude, and speed information. Using the relationship between speed, trajectory, and latitude and longitude, it determines whether the carrier is stationary or moving. Under stationary or moving conditions, it assesses the fluctuation of latitude, longitude, and speed data. If the fluctuation exceeds a predetermined threshold range, the satellite navigation positioning is considered abnormal. Finally, during the initial alignment process, it continuously assesses the correlation characteristics between the satellite navigation speed and latitude / longitude and the latitude, longitude, and speed information output during the initial alignment process to determine whether the satellite navigation is within the corresponding threshold range.

[0065] The effectiveness detection of the alignment process involves several steps. First, after continuously receiving valid satellite navigation data for 30 seconds, the device automatically begins the initial alignment process. For the first 100 seconds, dynamic analytical alignment is completed. After alignment, the device enters Kalman filter integrated navigation alignment. Second, during the initial alignment process, the effectiveness of the satellite navigation is monitored in real time. If invalid satellite navigation data occurs continuously for one minute, an initial alignment failure is indicated in the initial alignment status. Then, the initial alignment requires the platform to be either stationary or in uniform linear motion. Inertial devices and satellite navigation data are used to determine the platform's state. During the analytical alignment process, changes in satellite navigation trajectory and speed are analyzed. If both the device's speed and trajectory changes simultaneously exceed a specified threshold, the alignment is corrected. The equipment stops initial alignment, reports an abnormality in the initial alignment process, and indicates alignment failure. Then, within 240 seconds before the end of initial alignment, it detects changes in inertial navigation heading. If the heading change is greater than 45 degrees, it reports an abnormality in initial alignment maneuver and a decrease in alignment performance. Finally, it judges the position, velocity, heading, and attitude output by the inertial navigation system in real time. The position error should be less than 5 meters from the latitude and longitude error of the satellite navigation system, and the velocity error should be less than 0.1 knots. During uniform straight-line alignment, the rate of change of heading and the value of heading change should not exceed 1 degree per second and 90 degrees, respectively, and the attitude change should be less than 10 degrees. During stationary alignment, the rate of change of heading and the value of heading change should not exceed 0.1 degrees per second and 3 degrees, respectively, and the attitude change should be less than 1 degree.

[0066] System error monitoring involves several steps. First, real-time assessment of speed and heading errors during alignment. The speed error change in the northeast direction should be less than 0.002 m / s, and the heading error change should be less than 0.001° / s. Second, real-time assessment of system error estimation during the initial alignment process. During static alignment, the estimated speed error should not exceed 2 knots, and the heading error should not exceed 0.2 degrees. During uniform straight-line alignment, the estimated speed error should not exceed 4 knots, and the heading error should not exceed 1.0 degree. If these thresholds are exceeded, an abnormal system error estimation is reported. Third, real-time assessment of inertial device constant bias during alignment. The laser gyroscope bias should not exceed 0.1 degrees / hour, and the accelerometer constant bias should not exceed 500 μg. If these thresholds are exceeded, an inertial device output anomaly is reported. Finally, 30 seconds before the end of alignment, real-time detection of inertial device estimated bias is performed. The laser gyroscope bias should not exceed 0.02 degrees / hour, and the accelerometer constant bias should not exceed 200 μg. If these thresholds are exceeded, an inertial device output anomaly is reported.

[0067] Step (4) is a pure inertial navigation test, which mainly tests the validity of navigation information and the real-time status of the carrier.

[0068] The effectiveness of navigation information is first determined by assessing the vehicle's speed in real time. Based on the maximum speed of the moving vehicle, Vmax, and considering an inertial navigation speed error of 1 m / s, and assuming the pure inertial navigation time is t, the inertial navigation speed threshold is defined as V = Vmax / t. max +1.0t, real-time judgment of carrier speed. If the speed exceeds this value, navigation speed accuracy is abnormal. If it exceeds twice the threshold, navigation accuracy fault is directly output. Secondly, the angular velocity of the carrier is judged. The angular velocities in three directions are judged. If they exceed the specified threshold, the carrier angular velocity is abnormal. If it exceeds the maximum gyroscope angular velocity of 400° / s, the inertial navigation angular velocity fault is output.

[0069] The real-time status of the carrier is determined firstly by assessing its heading and attitude information. This information should be within a certain range; exceeding this range results in an attitude anomaly. Secondly, the output latitude and longitude position information is assessed. Based on the carrier's velocity V and inertial navigation velocity error δV, assuming initial latitude and longitude values ​​L0 and λ0 respectively, and a pure inertial navigation time of t, the latitude and longitude position range of the carrier is calculated. Taking the latitude calculation formula as an example, L = L0 + (V... max +δV)t / R (R is the Earth's radius), sending location information outside the location range is abnormal.

[0070] Step (5) is DVL speed integrated navigation detection, which mainly includes Doppler measurement information, speed integrated navigation status and navigation performance estimation.

[0071] The Doppler measurement information process involves several steps. First, Doppler measurement information is received in real time, and the interval between two adjacent sets of Doppler information is calculated. If the Doppler interval exceeds 2 seconds, the Doppler velocity data is considered discontinuous. If the interval lasts for more than 10 seconds, the discontinuity of the velocity data is reported. Second, the validity flag of the Doppler velocity message is used to determine whether the Doppler velocity is valid, and this information is sent in real time. Then, the validity of the Doppler velocity is determined in real time to decide whether the velocity information can be used for velocity-based navigation.

[0072] First, determine the speed range. The speed obtained from unpacking should be within the effective Doppler speed measurement range. The speed measurement value should be less than the maximum heading speed of the carrier. In addition, the speed value should be within a certain error range of the inertial navigation speed. If the speed is valid, speed combination can be performed.

[0073] Second, speed stability judgment: continuously save more than 3 sets of real-time continuous speed information, calculate their range, and the range should be less than the specified range threshold. If the speed measurement value is considered valid, speed combination navigation can be used.

[0074] Third, acceleration judgment: the effective velocity of Doppler is saved in real time and looped. The acceleration information of the carrier is obtained by subtracting the current velocity from the velocity at the previous moment. The acceleration information is compared with the acceleration information calculated by the inertial navigation system. The error should be less than the specified threshold. Otherwise, the Doppler velocity is judged to be invalid.

[0075] Fourth, assess the vehicle's maneuverability by measuring its heading angular rate and attitude angular velocity in real time. The measured values ​​should be within the corresponding threshold range to ensure that Doppler velocity measurement is real-time and accurate.

[0076] If the above four criteria are met, Doppler velocity can be combined with inertial navigation for velocity-integrated navigation.

[0077] The velocity-integrated navigation status detection process is as follows: First, if the Doppler bottom alignment velocity is valid and the bottom alignment depth is within the Doppler bottom alignment depth range, inertial navigation and Doppler are used for velocity-integrated navigation. The validity of the Doppler is assessed in real time. If the Doppler is invalid, the velocity-integrated navigation is terminated immediately, and Kalman filtering prediction is performed. Second, the pure inertial navigation latitude and longitude errors of the velocity-integrated navigation are detected in real time. The latitude and longitude errors should meet the pure inertial navigation positioning accuracy requirements. When the positioning error is greater than the nominal value of the inertial navigation error but less than twice the nominal value, a combined navigation warning is sent. If the navigation error is greater than twice the nominal value of the inertial navigation positioning error, an inertial navigation positioning accuracy anomaly is reported. Then, under normal combined navigation conditions, if the Doppler velocity is invalid for 5 consecutive minutes, a decrease in Doppler combined navigation accuracy is reported. If this exceeds half an hour, the inertial navigation is reported to be operating in pure inertial navigation mode. When the Doppler velocity becomes valid again, the velocity combination is reported to be valid, requiring satellite navigation to perform position calibration to improve the performance of the combined navigation data. Finally, if combined navigation operates continuously for 5 hours, the combined navigation accuracy is reported to require satellite navigation calibration.

[0078] Navigation performance estimation involves several steps. First, using the latitude and longitude errors estimated by the velocity-integrated navigation system, the pure inertial navigation accuracy is calculated in real time. If the positioning error is less than twice the nominal value, the navigation accuracy is reported as normal; otherwise, a decrease in pure inertial navigation performance is reported. Second, the pure inertial navigation velocity error is calculated in real time. When the velocity error is greater than twice the nominal value, satellite navigation calibration is required, and heading and attitude errors are monitored in real time. Third, the errors of the inertial navigation devices are detected. The zero bias of the laser gyroscope and the constant zero bias of the accelerometer should be within the specified threshold range. If the error exceeds the threshold range, an abnormality in the inertial device error is reported based on the integrated navigation accuracy.

[0079] Step (6) Satellite position integrated navigation detection, the detection content mainly includes satellite measurement information, position integrated navigation status and navigation performance estimation.

[0080] The satellite measurement information process involves several steps. First, continuous reception of satellite navigation information is performed; if the information is discontinuous, packet loss is reported. Second, the validity and positioning factors of the satellite navigation information are decrypted to determine its effectiveness. Finally, inertial navigation information is used to determine the validity of any undetermined navigation information.

[0081] First, the speed and position range are judged. The speed obtained from unpacking should be less than the maximum heading speed of the carrier. In addition, the speed value should be within a certain error range from the inertial navigation speed. The speed is considered valid. At the same time, the inertial navigation position error calculated by applying satellite navigation should be within a certain threshold range. The satellite navigation is considered valid.

[0082] Second, the stability of the position is judged by continuously saving more than three sets of real-time continuous position information and calculating their range. If the range is less than the specified range threshold, the position measurement value is considered valid and can be used for position combination navigation.

[0083] Third, position difference judgment: the effective latitude and longitude of satellite navigation are saved in real time and looped. The difference between the current latitude and longitude and the latitude and longitude of the previous moment is used to obtain the velocity information of the vehicle. This information is compared with the velocity information calculated by the inertial navigation system. The error should be less than the specified threshold. Otherwise, the satellite navigation position information is judged to be invalid.

[0084] If the above three criteria are met, satellite navigation position information can be combined with inertial navigation for position-integrated navigation.

[0085] The position-integrated navigation status detection process involves several steps. First, the validity of satellite navigation information is determined. If the position information is valid, inertial navigation (INS) and satellite navigation information are combined for position-integrated navigation, with the validity of satellite navigation being determined in real time. If satellite navigation is invalid, position-integrated navigation is discontinued, and Kalman filtering prediction is performed. Second, the pure INS latitude and longitude errors of the position-integrated navigation are detected in real time. The latitude and longitude errors should meet the pure INS positioning accuracy requirements. When the positioning error is greater than the nominal value of the INS error but less than twice the nominal value, a pure INS warning is sent. If the navigation error is greater than twice the nominal value of the INS positioning error, an INS positioning accuracy out-of-tolerance warning is sent. Then, under normal integrated navigation conditions, if the satellite position is invalid for 5 consecutive minutes, a decrease in position-integrated navigation accuracy is reported. If this exceeds half an hour, the INS is reported to be operating in pure INS navigation mode. When the satellite navigation accuracy is valid again, the position combination is reported to be valid. Finally, after 5 hours of continuous integrated navigation operation, closed-loop calibration of system errors and inertial device errors is performed.

[0086] Navigation performance estimation involves several steps. First, using the latitude and longitude errors estimated by the velocity-integrated navigation system, the pure inertial navigation accuracy is calculated in real time. If the positioning error is less than twice the nominal value, the navigation accuracy is reported as normal; otherwise, a decrease in pure inertial navigation performance is reported. Second, the pure inertial navigation velocity error is calculated in real time. When the velocity error is greater than twice the nominal value, satellite navigation calibration is required, and heading and attitude errors are monitored in real time. Third, the errors of the inertial navigation devices are detected. The zero bias of the laser gyroscope and the constant zero bias of the accelerometer should be within the specified threshold range. If the error exceeds the threshold range, an abnormality in the inertial device error is reported based on the integrated navigation accuracy.

[0087] This technical solution proposes a fault detection method for inertial navigation equipment based on laser gyroscopes, building upon existing inertial / satellite integrated navigation and inertial / Doppler integrated navigation methods. This method fully utilizes the characteristics of inertial navigation, satellite navigation, and Doppler information. Based on inertial device monitoring, it analyzes the operating status of the inertial devices, uses the accuracy of satellite navigation velocity and position to determine the validity of position, velocity, and attitude information in the inertial navigation system, and the validity of Doppler information. Simultaneously, it leverages the short-term stability of inertial navigation information to determine the validity of satellite navigation positioning data, significantly improving the satellite navigation system's anti-interference and anti-spoofing capabilities. Ultimately, this ensures that the inertial navigation system outputs truly effective navigation information.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0090] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fault detection method for inertial navigation equipment based on laser gyroscope, characterized in that: The steps are as follows: (1) All possible fault states and fault detection contents of laser inertial navigation are given. The fault state detection methods are different in different stages. At the same time, the fault detection contents under different working conditions are given. The specific detection methods are given later according to different fault detection contents. (2) The equipment performs a self-test upon startup, which mainly includes hardware initialization, parameter initialization, and inertial device testing. (3) Initial alignment, the main inspection contents include satellite guidance effectiveness, alignment process effectiveness and system error monitoring; (4) Pure inertial navigation detection, the main detection contents include the effectiveness of navigation information and the real-time status of the carrier; (5) DVL speed integrated navigation detection, the main detection contents include Doppler measurement information, speed integrated navigation status and navigation performance estimation; (6) Satellite position integrated navigation detection, the detection content mainly includes satellite measurement information, position integrated navigation status and navigation performance estimation; In particular, according to step (3) The satellite navigation validity detection process involves the following steps: After the equipment meets the initial alignment conditions, it receives navigation data from the satellite navigation system in real time. First, it checks the continuity of the data. If there is continuous data inconsistency or no data for more than 2 seconds, the satellite navigation data is considered to have poor continuity. If there is more than 30 seconds of invalid data within one minute, the system reports that the inertial navigation system does not meet the initial alignment conditions. Second, it unpacks the satellite navigation data packet protocol content, including the satellite navigation validity and HDR value, to determine if the satellite navigation is valid and meets the application conditions for inertial navigation initial alignment. Then, it evaluates the received satellite navigation latitude, longitude, altitude, and speed information. Using the relationship between speed, course, and latitude / longitude, it determines whether the carrier is stationary or moving. Under stationary or moving conditions, it assesses the fluctuation of latitude / longitude and speed data. If the fluctuation exceeds a predetermined threshold range, the satellite navigation positioning is considered abnormal. Finally, during the initial alignment process, it continuously assesses the correlation characteristics between the satellite navigation speed and latitude / longitude and the latitude / longitude and speed information output during the inertial navigation initial alignment process to determine if the satellite navigation is within the corresponding threshold range. The effectiveness detection of the alignment process involves several steps. First, after continuously receiving valid satellite navigation data for 30 seconds, the device automatically begins the initial alignment process. For the first 100 seconds, dynamic analytical alignment is completed. After alignment, the device enters Kalman filter integrated navigation alignment. Second, during the initial alignment process, the effectiveness of the satellite navigation is monitored in real time. If invalid satellite navigation data occurs continuously for one minute, an initial alignment failure is indicated in the initial alignment status. Then, the initial alignment requires the platform to be either stationary or in uniform linear motion. Inertial devices and satellite navigation data are used to determine the platform's state. During the analytical alignment process, changes in satellite navigation trajectory and speed are analyzed. If both the device's speed and trajectory changes simultaneously exceed a specified threshold, the alignment is corrected. The equipment stops initial alignment, reports an abnormality in the initial alignment process, and indicates alignment failure. Then, within 240 seconds before the end of the initial alignment, it detects changes in the inertial navigation heading. If the heading change is greater than 45 degrees, it reports an abnormality in the initial alignment maneuver and a decrease in alignment performance. Finally, it judges the position, velocity, heading, and attitude output by the inertial navigation system in real time. The position error should be less than 5 meters from the latitude and longitude error of the satellite navigation system, and the velocity error should be less than 0.1 knots. During uniform straight-line alignment, the rate of change of heading and the value of heading change should not exceed 1 degree per second and 90 degrees, respectively, and the attitude change should be less than 10 degrees. During stationary alignment, the rate of change of heading and the value of heading change should not exceed 0.1 degrees per second and 3 degrees, respectively, and the attitude change should be less than 1 degree. System error monitoring involves several steps. First, real-time assessment of speed and heading errors during alignment. The speed error change in the northeast direction should be less than 0.002 m / s, and the heading error change should be less than 0.001° / s. Second, real-time assessment of system error estimation during the initial alignment process. During static alignment, the estimated speed error should not exceed 2 knots, and the heading error should not exceed 0.2 degrees. During uniform straight-line alignment, the estimated speed error should not exceed 4 knots, and the heading error should not exceed 1.0 degree. If these thresholds are exceeded, an abnormal system error estimation is reported. Third, real-time assessment of inertial device constant bias during alignment. The laser gyroscope bias should not exceed 0.1 degrees / hour, and the accelerometer constant bias should not exceed 500 μg. If these thresholds are exceeded, an inertial device output anomaly is reported. Finally, 30 seconds before the end of alignment, real-time detection of inertial device estimated bias is performed. The laser gyroscope bias should not exceed 0.02 degrees / hour, and the accelerometer constant bias should not exceed 200 μg. If these thresholds are exceeded, an inertial device output anomaly is reported.

2. The fault detection method for inertial navigation equipment based on laser gyroscope according to claim 1, characterized in that: According to step (2), In the hardware initialization test, first check whether the navigation computer starts up normally; second, check whether the power supply voltage and current of the power module, IF conversion module and inertial device are normal; and finally, check whether the navigation computer's external interface initialization is normal. In the parameter initialization test, firstly, it checks whether the system navigation parameters saved by the hardware are normal. Secondly, it checks the system temperature and completes the configuration of relevant parameters for the temperature model of the laser gyroscope and accelerometer. Finally, it completes the initialization of relevant parameters for initial alignment, including alignment time, number of iterative alignments, and initialization of Kalman filter parameters, to ensure they are within the specified range. In inertial device testing, the laser gyroscope, quartz flexural accelerometer, and temperature parameters in the laser gyroscope inertial navigation device are read in real time.

3. The fault detection method for inertial navigation equipment based on laser gyroscope according to claim 2, characterized in that: The detection method for inertial devices is as follows: 1) Data validity assessment First, calculate the magnitude of the laser gyroscope and accelerometer data to be read, and the values ​​should be within the specified threshold range; then, calculate the range and volatility of the gyroscope and accelerometer data, which should also be within the corresponding threshold range. Finally, the combined angular velocity and acceleration of the laser gyroscope and accelerometer are calculated separately. Under static conditions, they should be basically consistent with the Earth's rotation angular velocity and gravitational acceleration. Under dynamic conditions, they should be within the corresponding threshold range. These evaluation methods are then used to check whether the measured values ​​are normal. 2) Judgment based on monitoring data, First, the laser gyroscope's light intensity, amplitude, frequency, and anode / cathode temperatures are received in real time to monitor its operational status. If the readings are outside the corresponding monitoring thresholds, the device is considered to be malfunctioning. Second, the accelerometer temperature is received in real time and compared with the laser gyroscope temperature. The temperature difference and rate of temperature change should be within the corresponding threshold ranges. Finally, the high-precision IF clock crystal oscillator is detected in real time, and it should be within a certain error range compared with the local computer crystal oscillator.

4. The fault detection method for inertial navigation equipment based on laser gyroscope according to claim 1, characterized in that: According to step (4) The effectiveness of navigation information is first determined by assessing the vehicle's speed in real time, based on the vehicle's maximum speed V. max Given an inertial navigation velocity error of 1 m / s, and assuming the pure inertial navigation time is t, the inertial navigation velocity threshold is defined as follows: The system first determines the carrier speed in real time. If the speed exceeds the value, it sends a navigation speed accuracy error. If the speed exceeds twice the threshold, it directly outputs a navigation accuracy fault. Secondly, it determines the carrier's angular velocity. It judges the angular velocity in three directions. If the angular velocity exceeds the specified threshold, it outputs a carrier angular velocity error. If the angular velocity exceeds the maximum gyroscope angular velocity of 400° / s, it outputs an inertial navigation angular velocity fault. The real-time status of the carrier is determined by first judging the carrier's heading and attitude information in real time. The attitude information should be within a certain range. If it exceeds the specified value, an attitude abnormality is output. Secondly, the output latitude and longitude location information is determined based on the carrier's velocity V and the inertial navigation speed error. V, let the initial latitude and longitude be respectively... The pure inertial navigation time is t. The latitude and longitude position range of the carrier is calculated respectively. If the position information is sent outside the position range, it is abnormal.

5. The fault detection method for inertial navigation equipment based on laser gyroscope according to claim 4, characterized in that: Taking the latitude calculation formula as an example, its calculation method is as follows: R is the Earth's radius.

6. The fault detection method for inertial navigation equipment based on laser gyroscope according to claim 1, characterized in that: According to step (5), The process for obtaining Doppler measurement information involves several steps. First, Doppler measurement information is received in real time, and the interval between two adjacent sets of Doppler information is calculated. If the Doppler interval exceeds 2 seconds, the Doppler velocity data is considered discontinuous; if it lasts for more than 10 seconds, the discontinuity is reported. Second, the validity flag of the Doppler velocity message is used to determine whether the Doppler velocity is valid, and this information is sent in real time. Then, the validity of the Doppler velocity is assessed in real time to determine whether the velocity information can be used for velocity-based navigation. For velocity-integrated navigation status detection, firstly, if the Doppler bottom alignment velocity is effective and the bottom alignment depth is within the Doppler bottom alignment depth range, the inertial navigation and Doppler will perform velocity-integrated navigation, and the effectiveness of Doppler will be judged in real time. If Doppler is invalid, the velocity-integrated navigation will be terminated in real time, and Kalman filter prediction will be performed. Secondly, the latitude and longitude errors of the pure inertial navigation system (INS) in real time are detected. The latitude and longitude errors should meet the positioning accuracy requirements of the pure INS. When the positioning error is greater than the nominal value of the INS error but less than twice the nominal value, a warning is sent for the integrated navigation system. If the navigation error is greater than twice the nominal value of the INS positioning error, an INS positioning accuracy anomaly is reported. Then, under normal integrated navigation conditions, if the Doppler velocity is invalid for 5 consecutive minutes, a decrease in Doppler integrated navigation accuracy is reported. If this exceeds half an hour, it is reported that the INS is operating in pure inertial navigation mode. When the Doppler velocity becomes valid again, the speed combination is reported as valid, and the satellite navigation system needs to perform position calibration to improve the performance of the integrated navigation data. Finally, if the integrated navigation system operates continuously for 5 hours, the integrated navigation accuracy needs to be calibrated by the satellite navigation system. Navigation performance estimation: First, using the latitude and longitude errors estimated by the velocity-integrated navigation, the pure inertial navigation accuracy of the inertial navigation system is calculated in real time. If the positioning error is less than twice the nominal positioning error value, the navigation accuracy is reported as normal; if it exceeds this value, the pure inertial navigation performance is reported as degraded. Secondly, the pure inertial navigation velocity error is calculated in real time. When the velocity error is greater than twice the nominal value, the satellite navigation calibration requirement is reported. At the same time, the heading and attitude errors are detected in real time. Then, the error of the inertial navigation device is detected. The zero bias value of the laser gyroscope and the constant zero bias value of the accelerometer should be within the specified threshold range. If the error exceeds the threshold range, the abnormality of the inertial device error is reported according to the accuracy of the integrated navigation.

7. A fault detection method for inertial navigation equipment based on laser gyroscope according to claim 6, characterized in that: The method for determining whether Doppler velocity is suitable for velocity-based navigation is as follows: 1) Speed ​​range judgment: The speed obtained by unpacking should be within the effective Doppler speed measurement range. The speed measurement value should be less than the maximum heading speed of the vehicle. In addition, the speed value should be within a certain error range of the inertial navigation speed. If the speed is valid, the speed can be combined. 2) Speed ​​stability judgment: continuously save more than 3 sets of real-time continuous speed information, calculate their range. If the range is less than the specified range threshold, the speed measurement value is considered valid and can be used for speed combination navigation. 3) Acceleration judgment: The effective velocity of Doppler is saved in real time and looped. The acceleration information of the carrier is obtained by subtracting the current velocity from the velocity at the previous moment. The acceleration information is compared with the acceleration information calculated by the inertial navigation system. The error should be less than the specified threshold. Otherwise, the Doppler velocity is judged to be invalid. 4) Vehicle maneuverability assessment: Real-time measurement of the vehicle's heading angular rate and attitude angular velocity. The measured values ​​should be within the corresponding threshold range to ensure that Doppler velocity measurement is real-time and accurate. If the above four criteria are met, Doppler velocity can be combined with inertial navigation for velocity-integrated navigation.

8. The fault detection method for inertial navigation equipment based on laser gyroscope according to claim 1, characterized in that: According to step (6), the satellite measurement information is firstly received continuously. When the satellite navigation information is discontinuous, the satellite navigation information packet loss is reported. Secondly, the validity and positioning factor of the satellite navigation are decrypted to determine the validity of the satellite navigation information. Then, the inertial navigation information is used to determine whether the undetermined navigation information is valid. The position integrated navigation status detection first determines the validity of the satellite navigation information. If the position information is valid, the inertial navigation and satellite navigation information are combined for position integrated navigation. The validity of the satellite navigation is determined in real time. If the satellite navigation is invalid, the position integrated navigation is terminated and Kalman filter prediction is performed. Secondly, the pure inertial navigation latitude and longitude error of the real-time position-degree integrated navigation is detected. The latitude and longitude error should meet the pure inertial navigation positioning accuracy. When the positioning error is greater than the nominal value of the inertial navigation error but less than twice the nominal value, a pure inertial navigation warning is sent. When the navigation error is greater than twice the nominal value of the inertial navigation positioning error, an inertial navigation positioning accuracy out-of-tolerance warning is sent. Then, under normal integrated navigation conditions, if the satellite position is invalid for 5 consecutive minutes, the position integrated navigation accuracy is reported to have decreased. If this continues for more than half an hour, the inertial navigation is reported to be operating in pure inertial navigation mode. When the satellite navigation accuracy is valid again, the position integration is reported to be valid. Finally, after 5 hours of continuous integrated navigation operation, the system error and inertial device error are calibrated in a closed loop. Navigation performance estimation: First, using the latitude and longitude errors estimated by the velocity-integrated navigation, the pure inertial navigation accuracy of the inertial navigation system is calculated in real time. If the positioning error is less than twice the nominal positioning error value, the navigation accuracy is reported as normal; if it exceeds this value, the pure inertial navigation performance is reported as degraded. Secondly, the pure inertial navigation velocity error is calculated in real time. When the velocity error is greater than twice the nominal value, the satellite navigation calibration requirement is reported. At the same time, the heading and attitude errors are detected in real time. Then, the error of the inertial navigation device is detected. The zero bias value of the laser gyroscope and the constant zero bias value of the accelerometer should be within the specified threshold range. If the error exceeds the threshold range, the abnormality of the inertial device error is reported according to the accuracy of the integrated navigation.

9. A fault detection method for inertial navigation equipment based on laser gyroscope according to claim 8, characterized in that: The method for determining the validity of undetermined navigation information using inertial navigation information is as follows: 1) Speed ​​and position range judgment: The speed obtained from unpacking should be less than the maximum heading speed of the vehicle. In addition, the speed value should be within a certain error range from the inertial navigation speed. The speed is considered valid. At the same time, the inertial navigation position error calculated by applying satellite navigation should be within a certain threshold range. The satellite navigation is considered valid. 2) Position stability judgment: continuously save more than 3 sets of real-time continuous position information, calculate their range. If the range is less than the specified range threshold, the position measurement value is considered valid and can be used for position combination navigation. 3) Position difference judgment: The effective latitude and longitude of satellite navigation are saved in real time. The difference between the current latitude and longitude and the latitude and longitude of the previous moment is used to obtain the velocity information of the vehicle. This information is compared with the velocity information calculated by the inertial navigation system. The error should be less than the specified threshold. Otherwise, the satellite navigation position information is judged to be invalid. If the above three criteria are met, satellite navigation position information can be combined with inertial navigation for position-integrated navigation.

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