Multi-redundancy integrated navigation system

Abstract

The invention relates to a redundancy integrated navigation system, which is characterized in that a modular redundancy integrated navigation system hardware platform is constructed, the redundancy integrated navigation system comprises two navigation modules with identical configuration, and each navigation module mainly comprises an array micro-electro-mechanical inertial measurement unit, a satellite navigation receiver, a magnetometer and a core processor; the array MEMS-IMU adopts a redundancy design, a plurality of MEMS-IMUs form an array, and fused angular velocity and acceleration information is obtained through fault detection and isolation and information fusion; performing fault detection and data selection on the satellite navigation receiver, and performing fault detection and data selection on the magnetometer; each navigation module carries out combined navigation calculation according to the data of the array micro-electro-mechanical inertial measurement unit, the data of the selected satellite navigation receiver and the data of the selected magnetometer; and finally, navigation data output selection is carried out. According to the scheme, system-level reliability and robustness are improved, long-time stable work of the system is guaranteed, and the method can be widely applied to pose measurement in the field of aerospace navigation.

Description

Technical Field

[0001] The invention relates to a redundancy combined navigation system, belonging to the technical field of aerospace navigation. Background Art

[0002] The integrated navigation system is an important component of the control system of various weapons and equipment. It combines multiple navigation methods such as inertial navigation and satellite navigation, and uses information fusion algorithms to accurately measure navigation information such as the carrier's real-time position, speed, and attitude. In order to reduce system costs while ensuring system reliability and stability, redundancy design methods are widely used. By increasing redundant components or functions in the system, when a component fails, other components can take over the work, thereby ensuring the normal operation of the system.

[0003] As more and more weapons and equipment put forward low-cost requirements, a large number of industrial-grade devices have been widely used. Compared with military-grade devices, industrial-grade devices have a large gap in reliability, stability and environmental adaptability. Redundancy design method is an effective means to solve this problem, and redundant configuration schemes, information fusion methods, fault detection and isolation methods, etc. have become hot spots and difficulties in redundancy design research. Summary of the invention

[0004] The technical problem solved by the present invention is: in view of the problem that the reliability, stability and environmental adaptability of industrial-grade components of weapons and equipment are not enough to adapt to the complex, changeable and harsh battlefield environment, a redundant combined navigation system is proposed by making full use of low-cost redundant inertial, satellite navigation, geomagnetic and other navigation sensors.

[0005] The technical scheme of the present invention is: a redundant combined navigation system, which includes the navigation system redundant configuration including two navigation modules with completely identical configurations, which are recorded as a first navigation module and a second navigation module, each navigation module has an array micro-electromechanical inertial measurement unit for measuring carrier angular velocity information and acceleration information; an onboard satellite navigation receiver for measuring the position and velocity information of the carrier; a geomagnetometer for measuring the local magnetic component information of the carrier; and a core processor for performing fault detection and isolation on the satellite navigation receiver and the geomagnetometer to obtain the preferred satellite navigation receiver and the geomagnetometer, and according to the array micro-electromechanical inertial measurement unit, the satellite navigation receiver and the geomagnetometer are selected. The data output by the unit is subjected to inertial navigation solution to obtain the inertial position, speed and attitude. Based on the inertial position, speed and attitude, the position speed information output by the satellite navigation receiver is preferably used, and the geomagnetic heading information output by the magnetometer is preferably used to perform combined navigation solution to obtain the navigation data of the carrier; the data of the three sensors, namely, the array micro-electromechanical inertial measurement unit, the satellite navigation receiver and the geomagnetic magnetometer, are simultaneously transmitted to the core processors in the two navigation modules, that is, the data of the three sensors in one navigation module are not only transmitted to the core processor in the current module through the internal circuit of the module, but also transmitted to the core processor in the other navigation module through the inter-board connector.

[0006] Preferably, the array micro-electromechanical inertial measurement unit includes 12 micro-electromechanical inertial measurement units and an inertial navigation processor. The 12 MEMS-IMUs are arranged three-dimensionally on a cubic metal base, with 4 MEMS-IMUs installed on the upper surface of the base, and 2 MEMS-IMUs installed on each of the four side surfaces of the base, for a total of 8 MEMS-IMUs; the 12 MEMS-IMUs each output their measured three-axis angular velocity signals and three-axis acceleration information, and the inertial navigation processor detects and isolates faults of the 12 MEMS-IMUs, determines the fault status of the 12 MEMS-IMUs, fuses and outputs the measurement data of the normal MEMS-IMUs, and isolates the measurement data of the faulty MEMS-IMUs.

[0007] Preferably, the specific method of MEMS-IMU fault detection and isolation is: determine whether the data output by the MEMS-IMU is continuously updated, if the data is not updated for a duration T, then determine that the MEMS-IMU is faulty; otherwise, further determine whether the data output by the MEMS-IMU is within a reasonable range, when and If the MEMS-IMU is normal, it is judged that the MEMS-IMU is faulty. It is the angular velocity signal and acceleration signal in the i direction output by the nth MEMS-IMU.

[0008] Preferably, the array micro-electromechanical inertial measurement unit information fusion method is: averaging the three-axis angular velocity signals and three-axis acceleration information output by N normally working MEMS-IMUs to obtain fused three-axis angular velocity signals and three-axis acceleration signals.

[0009] Preferably, the satellite navigation receiver fault detection includes two parts: GNSS status fault detection and GNSS numerical fault detection. The GNSS status fault detection directly determines whether the satellite navigation receiver is faulty through the satellite navigation receiver's own fault word, PDOP value, number of visible stars, and data update status; the GNSS numerical fault detection determines whether there is a fault through the validity of the numerical value output by the satellite navigation receiver; the GNSS status fault detection and the GNSS numerical fault detection have an "or" logical relationship, that is, if any one of the detection results is a fault, the satellite navigation receiver is considered to be faulty.

[0010] Preferably, the specific method of satellite navigation receiver status fault detection is: a) fault word judgment: the satellite navigation receiver data frame contains a positioning status word, and the fault is judged according to the positioning status word; b) PDOP value judgment: when the PDOP is less than 6, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; c) visible star judgment: when the number of visible stars is less than 4, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; d) data update detection: according to the time stamp data in the GNNS data frame, if it is not updated within a certain period of time T, it is considered that the GNSS status is faulty, otherwise it is normal; the above satellite navigation receiver status faults are in an "or" logical relationship, that is, if any of the status detection results is a fault, it is considered that the GNSS status is faulty;

[0011] GNSS numerical detection belongs to low-frequency detection. The following conditions should be met during GNSS numerical fault detection: the GNSS status fault detection result is normal; the navigation mode is the combined navigation mode; the array micro-electromechanical inertial measurement unit fault detection result is normal.

[0012] Preferably, the preferred satellite navigation receiver is selected by the following method:

[0013] The core processor in the first navigation module and the core processor in the second navigation module are selected according to their respective priorities, specifically: for the core processor in the first navigation module, the satellite navigation receiver in the first navigation module is given priority. When the satellite navigation receiver in the first navigation module fails, the satellite navigation receiver in the second navigation module is selected; for the core processor in the second navigation module, the satellite navigation receiver in the second navigation module is given priority. When the satellite navigation receiver in the second navigation module fails, the satellite navigation receiver in the first navigation module is selected.

[0014] Preferably, the specific process of performing fault detection on the geomagnetometer includes:

[0015] a) Data update detection: Based on the time stamp data in the geomagnetometer data frame, if it is not updated within a certain period of time T, it is considered that the geomagnetometer is faulty, otherwise it is normal; b) Validity judgment of the numerical range: When the value of the magnetic component of any axis is greater than the threshold Tm, it is considered that the geomagnetometer is faulty at that moment, otherwise it is normal; c) Validity judgment of the magnetic heading value: Compare the geomagnetic heading angle obtained by the navigation solution with the inertial yaw angle, and when the difference between the two is greater than the threshold Tmpsi, it is considered that the geomagnetometer is faulty at that moment; the above geomagnetometer faults are in an "or" logical relationship, that is, if any of the detection results is a fault, the geomagnetometer state is considered to be faulty.

[0016] Preferably, the geomagnetic heading data participating in the combined navigation is selected according to the fault status of the magnetometer in the first navigation module and the magnetometer in the second navigation module, and the core processor in the first navigation module and the core processor in the second navigation module are selected according to their respective priorities, specifically: for the core processor in the first navigation module, the magnetometer in the first navigation module is preferentially selected, and when the magnetometer in the first navigation module fails, the magnetometer in the second navigation module is selected; for the core processor in the second navigation module, the magnetometer in the second navigation module is preferentially selected, and when the magnetometer in the second navigation module fails, the magnetometer in the first navigation module is selected.

[0017] Preferably, the specific process of selecting the navigation data output is as follows: the core processor in the first navigation processing module outputs the first navigation data, and the core processor in the second navigation processing module outputs the second navigation data. The interface processing chip in the interface module determines the final output navigation data according to the priority. The first navigation data has a higher priority than the second navigation data, that is, the first navigation data is output first.

[0018] The advantages of the present invention compared with the prior art are:

[0019] (1) The present invention provides a redundant combined navigation method and system, which adopts a "modular" design concept to construct a redundant hardware platform, including a redundant array micro-electromechanical inertial measurement unit, a dual-redundant satellite navigation receiver, a dual-redundant geomagnetometer, and a combined navigation system of a dual-redundant core processor. Each redundant device can back up each other, and when one fails, it can be replaced by another, thereby improving the system hardware fault tolerance.

[0020] (2) The present invention can effectively improve the system reliability and robustness through system multi-redundancy configuration design, sensor fault detection and isolation, information fusion and other methods, ensuring that the system can obtain navigation information such as the real-time speed, position and attitude of the carrier in a long-term and stable manner, and has good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the composition of the redundant combined navigation system provided for the invention;

[0022] Figure 2 A schematic diagram of the working principle of the redundancy combined navigation system provided for the invention. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The present invention provides a redundant combined navigation system, which improves system-level reliability and robustness through redundant method configuration, system architecture, fault detection and isolation, information fusion and other designs, ensures long-term stable operation of the system, and realizes measurement of navigation information such as carrier speed, position and attitude.

[0025] (1) Construct a “modular” redundant integrated navigation system hardware platform;

[0026] The specific method of building the hardware platform of the integrated navigation system is as follows: the hardware of the redundant integrated navigation system adopts a "modular" design concept, including two navigation modules, one power module and one interface module. The navigation module is the core of the system, mainly composed of navigation sensors and core processors, and is used for information collection and navigation solution; the power module is used to power the system; the interface module is responsible for information input and output. Each module is stacked and connected, and signal and power transmission can be achieved through the board connector.

[0027] (2) Determine the redundant configuration scheme of the navigation module;

[0028] The specific method for determining the redundant configuration scheme of the navigation module is as follows: the redundant configuration includes two navigation modules with exactly the same configuration, which are denoted as the first navigation module and the second navigation module, and each navigation module includes an array micro-electromechanical inertial measurement unit for measuring the angular velocity information and acceleration information of the carrier; an onboard satellite navigation receiver for measuring the position and velocity information of the carrier; a magnetometer for measuring the local magnetic component information of the carrier; and a core processor for collecting sensor data, performing fault detection and isolation on the satellite navigation receiver and the magnetometer, and obtaining the preferred satellite navigation receiver and the magnetometer, and selecting the optimal satellite navigation receiver and the magnetometer according to the array micro-electromechanical inertial measurement unit. The data output by the element are used for inertial navigation solution to obtain the inertial position, speed and attitude; based on the inertial position, speed and attitude, the position and speed information output by the satellite navigation receiver and the geomagnetic heading information output by the magnetometer are preferably used for combined navigation solution to obtain the navigation data of the carrier; the data of the three sensors, namely, the array micro-electromechanical inertial measurement unit, the satellite navigation receiver and the geomagnetic heading information, are simultaneously transmitted to the core processors in the two navigation modules, that is, the data of the three sensors in one navigation module are not only transmitted to the core processor in the current module through the internal circuit of the module, but also transmitted to the core processor in the other navigation module through the inter-board connector.

[0029] (3) Determine the redundant configuration, fault detection and isolation, and fusion methods of the array micro-electromechanical inertial measurement unit;

[0030] The array micro-electromechanical inertial measurement unit includes 12 micro-electromechanical inertial measurement units (MEMS-IMU) and an inertial navigation processor. The 12 MEMS-IMUs are arranged three-dimensionally on a cubic metal base. Four MEMS-IMUs are installed on the upper surface of the base, and two MEMS-IMUs are installed on each of the four sides of the base, a total of eight MEMS-IMUs. Each of the 12 MEMS-IMUs can output its measured three-axis angular velocity signal and three-axis acceleration information. The inertial navigation processor detects and isolates faults of the 12 MEMS-IMUs, determines the fault status of the 12 MEMS-IMUs, fuses and outputs the measurement data of the normal MEMS-IMUs, and isolates the measurement data of the faulty MEMS-IMUs.

[0031] The specific method of fault detection and isolation of array micro-electromechanical inertial measurement unit is: determine whether the data output by MEMS-IMU is continuously updated. If it is not updated for a duration of T, it is determined that the MEMS-IMU is faulty; otherwise, further determine whether the data output by MEMS-IMU is within a reasonable range. and If the MEMS-IMU is normal, it is judged that the MEMS-IMU is faulty. The angular velocity signal and acceleration signal in the i direction output by the nth MEMS-IMU. Duration T, threshold Tg min, Tg max 、 min 、 max Can be set in advance based on experience.

[0032] The information fusion method of the array micro-electromechanical inertial measurement unit is specifically as follows: by averaging the three-axis angular velocity signals and three-axis acceleration information output by N normally working MEMS-IMUs, the fused three-axis angular velocity signals and three-axis acceleration signals can be obtained.

[0033] (4) Perform fault detection and data selection on satellite navigation receivers;

[0034] The specific method for fault detection and data selection of satellite navigation receivers is as follows: satellite navigation receiver fault detection includes two parts: GNSS status fault detection and GNSS numerical fault detection. Among them, GNSS status fault detection directly determines whether the satellite navigation receiver is faulty through the satellite navigation receiver's own fault word, PDOP value, number of visible stars, and data update status; GNSS numerical fault detection determines whether there is a fault by checking the numerical validity of the satellite navigation receiver's output; GNSS status fault detection and GNSS numerical fault detection are in an "or" logical relationship, that is, if any of the detection results is a fault, the satellite navigation receiver is considered to be faulty.

[0035] The specific method of GNSS status fault detection is: a) Fault word judgment: The satellite navigation receiver data frame contains the positioning status word, and the fault is judged according to the positioning status word; b) PDOP value judgment: When the PDOP is less than 6, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; c) Visible star judgment: When the number of visible stars is less than 4, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; d) Data update detection: Based on the time stamp data in the GNNS data frame, if it is not updated for a certain period of time T, it is considered that the GNSS status is faulty, otherwise it is normal; the above satellite navigation receiver status failures are in an "or" logical relationship, that is, if any of the status detection results is a fault, it is considered that the GNSS status is faulty.

[0036] The specific method of GNSS numerical fault detection is:

[0037] GNSS numerical fault detection is to determine whether the satellite navigation receiver has a numerical fault through the residual chi-square test at each integrated navigation filter node. The corresponding residuals can be determined according to the speed and position of the satellite navigation receiver. The residual r of the Kalman filter k Expressed as

[0038]

[0039] Where Z kis the observed value at time k, obtained from the output of the satellite navigation receiver and the result of inertial navigation solution; H k is the observation matrix; is the one-step prediction value of the state. When no fault occurs, r k is a Gaussian white noise with a mean of zero and a theoretical variance of Where P k / k-1 is the state one-step prediction mean square error matrix, R k is the observation noise matrix. When a system failure occurs, the residual r k The mean of is no longer zero. Therefore, by testing the residual mean, we can determine whether the system has failed. k Make the following binary assumptions: H0 (no fault): E (r k )=0, H1(faulty):E(r k )=μ, The fault detection function is

[0040]

[0041] Where: k is subject to χ with m degrees of freedom 2 distribution, i.e., λ k ~x 2 (m)(m is the observed quantity Z k The fault judgment criterion is: if λ k >T D , it is determined that there is a fault; if λ k ≤T D , judged that there is no fault. The preset threshold T D Determined by the false alarm rate.

[0042] GNSS numerical detection belongs to low-frequency detection. GNSS numerical fault detection should meet the following conditions: the GNSS status fault detection result is normal; the navigation mode is the combined navigation mode; the array micro-electromechanical inertial measurement unit fault detection result is normal.

[0043] Satellite navigation receiver data for combined navigation is selected according to the fault status of the satellite navigation receiver in the first navigation module (denoted as GNSS1) and the satellite navigation receiver in the second navigation module (denoted as GNSS2). The core processor in the first navigation module (denoted as core processor 1) and the core processor in the second navigation module (denoted as core processor 2) are selected according to their respective priorities, specifically: for core processor 1, GNSS1 is selected first, and when GNSS1 fails, GNSS2 is selected; for core processor 2, GNSS2 is selected first, and when GNSS2 fails, GNSS1 is selected.

[0044] (5) Perform fault detection and data selection on the magnetometer;

[0045] The specific method for fault detection and data selection of the geomagnetometer is:

[0046] The fault detection of geomagnetometer mainly includes: a) data update detection: according to the time stamp data in the geomagnetometer data frame, if it is not updated within a certain period of time T, it is considered that the geomagnetometer is faulty, otherwise it is normal; b) effective judgment of the value range: when the value of the magnetic component of any axis is greater than the threshold (Tm), it is considered that the geomagnetometer is faulty at that moment, otherwise it is normal; c) effective judgment of the magnetic heading value: compare the geomagnetic heading angle obtained by navigation solution with the inertial yaw angle, and when the difference between the two is greater than the threshold (Tmpsi), it is considered that the geomagnetometer is faulty at that moment. The above geomagnetometer faults are in the logical relationship of "or", that is, if any of the detection results is a fault, the geomagnetometer state is considered to be faulty.

[0047] According to the fault status of the magnetometer in the first navigation module (denoted as magnetometer 1) and the magnetometer in the second navigation module (denoted as magnetometer 2), the geomagnetic heading data for combined navigation is selected. The core processor in the first navigation module (denoted as core processor 1) and the core processor in the second navigation module (denoted as core processor 2) are selected according to their respective priorities, specifically: for core processor 1, magnetometer 1 is preferentially selected, and when magnetometer 1 fails, magnetometer 2 is selected; for core processor 2, magnetometer 2 is preferentially selected, and when magnetometer 2 fails, magnetometer 1 is selected.

[0048] (6) Each navigation module performs combined navigation solution based on its array micro-electromechanical inertial measurement unit data, selected satellite navigation receiver data, and selected magnetometer data.

[0049] The specific method for each navigation module to perform combined navigation solution based on its array micro-electromechanical inertial measurement unit data, selected satellite navigation receiver data, and selected geomagnetic data is as follows:

[0050] The three-axis angular velocity signal and three-axis acceleration signal output by the array micro-electromechanical inertial measurement unit are subjected to strapdown inertial navigation solution to obtain the inertial navigation solution speed, position and attitude results; the difference between the inertial navigation speed and the satellite navigation receiver speed, the difference between the inertial navigation position and the satellite navigation receiver position, and the difference between the inertial navigation heading angle and the geomagnetic heading angle are given to the Kalman filter as observation quantities, and the Kalman filter is used to estimate the system speed, position and attitude errors, and then feedback correction is performed to obtain the accurate speed, position and attitude information of the carrier to complete the combined navigation solution.

[0051] (7) Navigation data output selection;

[0052] The specific method for selecting navigation data output is: the core processor in the first navigation processing module outputs the first navigation data, and the core processor in the second navigation processing module outputs the second navigation data. The interface processing chip in the interface module determines the final output navigation data according to the priority. The first navigation data has a higher priority than the second navigation data, that is, the first navigation data is output first.

[0053] The following is further described based on specific embodiments:

[0054] In the current embodiment, a redundant combined navigation method and system is a method for improving system-level reliability and robustness, ensuring long-term stable operation of the system, and realizing measurement of navigation information such as carrier speed, position and attitude through redundant method configuration, system architecture, fault detection and isolation, information fusion and other designs. Figure 1 As shown, the redundant integrated navigation system refers to an integrated navigation system comprising a redundant array micro-electromechanical inertial measurement unit, a dual-redundant satellite navigation receiver, a dual-redundant geomagnetometer, and a dual-redundant core processor. Figure 2 As shown, a redundant combined navigation method has the following specific steps:

[0055] (1) Constructing a "modular" redundant integrated navigation system hardware platform: The redundant integrated navigation system hardware adopts a "modular" design concept, including two navigation modules, one power module and one interface module. The navigation module is the core of the system, mainly composed of navigation sensors and core processors, and is used for information collection and navigation solution; the power module is used to power the system; the interface module is responsible for information input and output. Each module is stacked and connected, and signal and power transmission can be achieved through the board connector.

[0056] (2) Determine a redundant configuration scheme for the navigation module; the redundant configuration includes two navigation modules with exactly the same configuration, denoted as the first navigation module and the second navigation module, each navigation module includes an array micro-electromechanical inertial measurement unit for measuring the angular velocity information and acceleration information of the carrier; an onboard satellite navigation receiver for measuring the position and velocity information of the carrier; a geomagnetometer for measuring the local magnetic component information of the carrier; and a core processor for collecting sensor data, performing fault detection and isolation on the satellite navigation receiver and the geomagnetometer, and obtaining the optimal satellite navigation receiver and geomagnetometer, and selecting the optimal satellite navigation receiver and geomagnetometer according to the input of the array micro-electromechanical inertial measurement unit. The data output is used for inertial navigation solution to obtain the inertial position, speed and attitude; based on the inertial position, speed and attitude, the position and speed information output by the satellite navigation receiver and the geomagnetic heading information output by the magnetometer are preferably used for combined navigation solution to obtain the navigation data of the carrier; the data of the three sensors, namely, the array micro-electromechanical inertial measurement unit, the satellite navigation receiver and the geomagnetic magnetometer, are simultaneously transmitted to the core processors in the two navigation modules, that is, the data of the three sensors in one navigation module are not only transmitted to the core processor in the current module through the internal circuit of the module, but also transmitted to the core processor in the other navigation module through the inter-board connector.

[0057] (3) Determine the redundant configuration, fault detection and isolation, and fusion methods of the array microelectromechanical inertial measurement unit: First, the array microelectromechanical inertial measurement unit includes 12 microelectromechanical inertial measurement units (MEMS-IMU) and an inertial navigation processor. The 12 MEMS-IMUs are arranged in a three-dimensional manner on a cubic metal base. Four MEMS-IMUs are installed on the upper surface of the base, and two MEMS-IMUs are installed on each of the four sides of the base, totaling 8 MEMS-IMUs. The 12 MEMS-IMUs can each output the three-axis angular velocity signal and three-axis acceleration information they measure. The inertial navigation processor detects and isolates the faults of the 12 MEMS-IMUs, determines the fault status of the 12 MEMS-IMUs, fuses and outputs the measurement data of the normal MEMS-IMUs, and isolates the measurement data of the faulty MEMS-IMUs.

[0058] The specific method of fault detection and isolation of array micro-electromechanical inertial measurement unit is: determine whether the data output by MEMS-IMU is continuously updated. If it is not updated for a duration of T, it is determined that the MEMS-IMU is faulty; otherwise, further determine whether the data output by MEMS-IMU is within a reasonable range. and If the MEMS-IMU is normal, it is judged that the MEMS-IMU is faulty. The angular velocity signal and acceleration signal in the i direction output by the nth MEMS-IMU. Duration T, threshold Tg min , Tg max 、min 、 max Can be set in advance based on experience.

[0059] Finally, by averaging the three-axis angular velocity signals and three-axis acceleration information output by N normally working MEMS-IMUs, the fused three-axis angular velocity signals and three-axis acceleration signals can be obtained.

[0060] (4) Fault detection and data selection for satellite navigation receivers: Satellite navigation receiver fault detection includes two parts: GNSS status fault detection and GNSS numerical fault detection. The GNSS status fault detection directly determines whether the satellite navigation receiver is faulty through the satellite navigation receiver's own fault word, PDOP value, number of visible stars, and data update status. The GNSS numerical fault detection determines whether a fault exists by checking the numerical validity of the satellite navigation receiver's output. The GNSS status fault detection and GNSS numerical fault detection have an "or" logical relationship, that is, if any of the detection results is a fault, the satellite navigation receiver is considered to be faulty.

[0061] The specific method of GNSS status fault detection is: a) fault word judgment: the satellite navigation receiver data frame contains the positioning status word, and the fault is judged according to the positioning status word; b) PDOP value judgment: when the PDOP is less than 6, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; c) visible star judgment: when the number of visible stars is less than 4, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; d) data update detection: based on the time stamp data in the GNNS data frame, if it is not updated for a certain period of time T, it is considered that the GNSS status is faulty, otherwise it is normal; the above satellite navigation receiver status failures are in an "or" logical relationship, that is, if any of the status detection results is a fault, it is considered that the GNSS status is faulty.

[0062] The specific method of GNSS numerical fault detection is as follows: GNSS numerical fault detection is to determine whether the satellite navigation receiver has a numerical fault through the residual chi-square test at each combined navigation filter node. The corresponding residuals can be determined according to the speed and position of the satellite navigation receiver. The residual r of the Kalman filter k Expressed as

[0063]

[0064] Where Z k is the observed value at time k, obtained from the output of the satellite navigation receiver and the result of inertial navigation solution; H k is the observation matrix; is the one-step prediction value of the state. When no fault occurs, r k is a Gaussian white noise with a mean of zero and a theoretical variance of Where P k / k-1 is the state one-step prediction mean square error matrix, R k is the observation noise matrix. When a system failure occurs, the residual r k The mean of is no longer zero. Therefore, by testing the residual mean, we can determine whether the system has failed. k Make the following binary assumptions: H0 (no fault): E (r k )=0, H1(faulty):E(r k )=μ, The fault detection function is

[0065]

[0066] Where: k is subject to χ with m degrees of freedom 2 distribution, i.e., λ k ~x 2 (m)(m is the observed quantity Z k The fault judgment criterion is: if λ k >T D , it is determined that there is a fault; if λ k ≤T D , judged that there is no fault. The preset threshold T D Determined by the false alarm rate.

[0067] It is worth noting that GNSS numerical detection is a low-frequency detection, and GNSS numerical fault detection should meet the following conditions: the GNSS status fault detection result is normal; the navigation mode is the combined navigation mode; the array micro-electromechanical inertial measurement unit fault detection result is normal.

[0068] Satellite navigation receiver data for combined navigation is selected according to the fault status of the satellite navigation receiver in the first navigation module (denoted as GNSS1) and the satellite navigation receiver in the second navigation module (denoted as GNSS2). The core processor in the first navigation module (denoted as core processor 1) and the core processor in the second navigation module (denoted as core processor 2) are selected according to their respective priorities, specifically: for core processor 1, GNSS1 is selected first, and when GNSS1 fails, GNSS2 is selected; for core processor 2, GNSS2 is selected first, and when GNSS2 fails, GNSS1 is selected.

[0069] Fault detection and data selection for the geomagnetometer: The fault detection of the geomagnetometer mainly includes: a) Data update detection: According to the time stamp data in the geomagnetometer data frame, if it is not updated within a certain period of time T, the geomagnetometer is considered to be faulty, otherwise it is normal; b) Validity judgment of the value range: When the value of the magnetic component of any axis is greater than the threshold (Tm), the geomagnetometer is considered to be faulty at that moment, otherwise it is normal; c) Validity judgment of the magnetic heading value: Compare the geomagnetic heading angle obtained by the navigation solution with the inertial yaw angle, and when the difference between the two is greater than the threshold (Tmpsi), the geomagnetometer is considered to be faulty at that moment. The above geomagnetometer faults are "or" logical relationships, that is, if any of the detection results is a fault, the geomagnetometer state is considered to be faulty.

[0070] According to the fault status of the magnetometer in the first navigation module (denoted as magnetometer 1) and the magnetometer in the second navigation module (denoted as magnetometer 2), the geomagnetic heading data for combined navigation is selected. The core processor in the first navigation module (denoted as core processor 1) and the core processor in the second navigation module (denoted as core processor 2) are selected according to their respective priorities, specifically: for core processor 1, magnetometer 1 is preferentially selected, and when magnetometer 1 fails, magnetometer 2 is selected; for core processor 2, magnetometer 2 is preferentially selected, and when magnetometer 2 fails, magnetometer 1 is selected.

[0071] (5) Each navigation module performs combined navigation solution according to its array micro-electromechanical inertial measurement unit data, selected satellite navigation receiver data, and selected geomagnetic data: the three-axis angular velocity signal and the three-axis acceleration signal output by the array micro-electromechanical inertial measurement unit are subjected to strapdown inertial navigation solution to obtain the inertial navigation solution speed, position and attitude results; the difference between the inertial navigation speed and the satellite navigation receiver speed, the difference between the inertial navigation position and the satellite navigation receiver position, and the difference between the inertial navigation heading angle and the geomagnetic heading angle are given as observation quantities to the Kalman filter, and the system speed, position and attitude errors are estimated through the Kalman filter, and feedback correction is then performed to obtain the accurate speed, position and attitude information of the carrier to complete the combined navigation solution.

[0072] (6) Navigation data output selection: The core processor in the first navigation processing module outputs the first navigation data, and the core processor in the second navigation processing module outputs the second navigation data. The interface processing chip in the interface module determines the final output navigation data according to the priority. The first navigation data has a higher priority than the second navigation data, that is, the first navigation data is output first.

[0073] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0074] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A redundant integrated navigation system, characterized in that The redundant configuration of the navigation system includes two navigation modules with exactly the same configuration, which are denoted as a first navigation module and a second navigation module, and each navigation module has an array micro-electromechanical inertial measurement unit for measuring the angular velocity information and acceleration information of the carrier; 1 onboard satellite navigation receiver for measuring the position and velocity information of the carrier; 1 magnetometer, used to measure the local magnetic component information of the carrier; 1 core processor, performs fault detection and isolation on the satellite navigation receiver and the magnetometer, obtains the preferred satellite navigation receiver and the magnetometer, performs inertial navigation solution according to the data output by the array micro-electromechanical inertial measurement unit to obtain the inertial position, speed and attitude, performs combined navigation solution based on the inertial position, speed and attitude, preferably the position speed information output by the satellite navigation receiver, preferably the geomagnetic heading information output by the magnetometer, and obtains the navigation data of the carrier; the data of the three sensors of the array micro-electromechanical inertial measurement unit, the satellite navigation receiver and the magnetometer are simultaneously transmitted to the core processors in the two navigation modules, that is, the three sensor data in one navigation module are not only transmitted to the core processor in the current module through the internal circuit of the module, but also transmitted to the core processor in another navigation module through the inter-board connector.

2. A redundancy integrated navigation system according to claim 1, characterized in that: The array micro-electromechanical inertial measurement unit includes 12 micro-electromechanical inertial measurement units (MEMS-IMU) and an inertial navigation processor. The 12 MEMS-IMUs are arranged three-dimensionally on a cubic metal base. Four MEMS-IMUs are installed on the upper surface of the base, and two MEMS-IMUs are installed on each of the four side surfaces of the base, for a total of eight MEMS-IMUs. The 12 MEMS-IMUs each output their measured three-axis angular velocity signals and three-axis acceleration information. The inertial navigation processor detects and isolates faults of the 12 MEMS-IMUs, determines the fault states of the 12 MEMS-IMUs, fuses and outputs the measurement data of normal MEMS-IMUs, and isolates the measurement data of the faulty MEMS-IMUs.

3. A redundancy integrated navigation system according to claim 2, characterized in that: The specific method of MEMS-IMU fault detection and isolation is: determine whether the data output by the MEMS-IMU is continuously updated. If it is not updated for a duration of T, the MEMS-IMU is considered to be faulty; otherwise, further determine whether the data output by the MEMS-IMU is within a reasonable range. When Tg min ≤ω i n ≤Tg max and If the MEMS-IMU is normal, it is judged that the MEMS-IMU is faulty. It is the angular velocity signal and acceleration signal in the i direction output by the nth MEMS-IMU.

4. A redundancy integrated navigation system according to claim 2, characterized in that: The array micro-electromechanical inertial measurement unit information fusion method is: averaging the three-axis angular velocity signals and three-axis acceleration information output by N normally functioning MEMS-IMUs to obtain fused three-axis angular velocity signals and three-axis acceleration signals.

5. The redundancy integrated navigation system according to claim 1, characterized in that: Satellite navigation receiver fault detection includes two parts: GNSS status fault detection and GNSS numerical fault detection. Among them, GNSS status fault detection directly determines whether the satellite navigation receiver is faulty through the satellite navigation receiver's own fault word, PDOP value, number of visible satellites, and data update status; GNSS numerical fault detection determines whether there is a fault by checking the numerical validity of the satellite navigation receiver's output; GNSS status fault detection and GNSS numerical fault detection have an "or" logical relationship, that is, if any of the detection results is a fault, the satellite navigation receiver is considered to be faulty.

6. A redundancy integrated navigation system according to claim 1, characterized in that: The specific method of satellite navigation receiver status fault detection is: a) Fault word judgment: the satellite navigation receiver data frame contains the positioning status word, and the fault judgment is performed according to the positioning status word; b) PDOP value judgment: when the PDOP is less than 6, the satellite navigation receiver status is judged to be faulty, otherwise it is normal; c) Visible star judgment: When the number of visible stars is less than 4, the satellite navigation receiver is judged to be in fault state, otherwise it is normal; d) Data update detection: Based on the time stamp data in the GNNS data frame, if it is not updated within a certain period of time T, it is considered that the GNSS state is faulty, otherwise it is normal; the above satellite navigation receiver state failures are in an "or" logical relationship, that is, if any state detection result is a failure, it is considered that the GNSS state is faulty; GNSS numerical detection belongs to low-frequency detection. The following conditions should be met during GNSS numerical fault detection: the GNSS status fault detection result is normal; The navigation mode is a combined navigation mode; The array micro-electromechanical inertial measurement unit fault detection result is normal.

7. A redundancy integrated navigation system according to claim 1, characterized in that: The preferred satellite navigation receiver is selected by: The core processor in the first navigation module and the core processor in the second navigation module are selected according to their respective priorities, specifically: for the core processor in the first navigation module, the satellite navigation receiver in the first navigation module is preferentially selected, and when the satellite navigation receiver in the first navigation module fails, the satellite navigation receiver in the second navigation module is selected; For the core processor in the second navigation module, the satellite navigation receiver in the second navigation module is preferentially selected. When the satellite navigation receiver in the second navigation module fails, the satellite navigation receiver in the first navigation module is selected.

8. A redundancy integrated navigation system according to claim 1, characterized in that: The specific process of fault detection of the magnetometer includes: a) Data update detection: Based on the time stamp data in the geomagnetometer data frame, if it is not updated within a certain period of time T, it is considered that the geomagnetometer is faulty, otherwise it is normal; b) Validity judgment of the value range: When the value of the magnetic component of any axis is greater than the threshold Tm, it is considered that the geomagnetometer is faulty at that moment, otherwise it is normal; c) Validity judgment of the magnetic heading value: Compare the geomagnetic heading angle obtained by navigation solution with the inertial yaw angle, and when the difference between the two is greater than the threshold Tmpsi, it is considered that the geomagnetometer is faulty at that moment; the above geomagnetometer faults are in an "or" logical relationship, that is, if any of the detection results is a fault, the geomagnetometer state is considered to be faulty.

9. A redundancy integrated navigation system according to claim 1, characterized in that: According to the fault status of the magnetometer in the first navigation module and the magnetometer in the second navigation module, the geomagnetic heading data participating in the combined navigation is selected, and the core processor in the first navigation module and the core processor in the second navigation module are selected according to their respective priorities, specifically: for the core processor in the first navigation module, the magnetometer in the first navigation module is preferentially selected, and when the magnetometer in the first navigation module fails, the magnetometer in the second navigation module is selected; for the core processor in the second navigation module, the magnetometer in the second navigation module is preferentially selected, and when the magnetometer in the second navigation module fails, the magnetometer in the first navigation module is selected.

10. The redundancy integrated navigation system according to claim 1, characterized in that: The specific process of selecting the navigation data output is as follows: the core processor in the first navigation processing module outputs the first navigation data, and the core processor in the second navigation processing module outputs the second navigation data. The interface processing chip in the interface module determines the final output navigation data according to the priority. The first navigation data has a higher priority than the second navigation data, that is, the first navigation data is output first.

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