Combined navigation system, method, aircraft and computer readable storage medium

Abstract

The application discloses a kind of combined navigation system, method, aircraft and computer readable storage medium, belong to aircraft navigation technical field.The combined navigation system includes: visual / inertial navigation module, visual / inertial navigation module is used to generate relative positioning information based on visual positioning data and inertial data;Wherein, relative positioning information produces drift error with time accumulation;Anti-jamming receiver, anti-jamming receiver is used to receive satellite signal, suppress jamming signal and deception jamming signal in satellite signal, and output absolute positioning information;Fusion processing module, fusion processing module is used to correct relative positioning information based on absolute positioning information and output navigation parameter, to suppress drift error.The application adopts anti-jamming receiver capable of suppressing jamming signal and deception jamming signal, can provide reliable absolute position reference, avoids the problem of insufficient navigation accuracy of pure visual / inertial combined navigation system in complex electromagnetic environment.

Description

Technical Field

[0001] This application relates to the field of aircraft navigation technology, and more particularly to integrated navigation systems, methods, aircraft, and computer-readable storage media. Background Technology

[0002] When aircraft perform missions in environments with signal rejection or interference, they typically employ a visual / inertial integrated navigation system to achieve autonomous positioning and navigation. This system obtains visual positioning data by comparing images acquired by a downward-looking camera with pre-stored maps in real time, and combines this with inertial navigation data for integrated navigation, thus outputting navigation parameters such as speed, position, and attitude.

[0003] However, a pure vision / inertial navigation system is a relative measurement system. In complex electromagnetic environments, the ordinary satellite receivers configured in this system are prone to losing lock and are more susceptible to being hijacked by spoofed signals. They cannot provide a reliable absolute position reference for the system. As the flight time and distance increase, the system's position and heading errors will continue to accumulate, and the drift rate can usually reach 1% to 2% of the travel distance. Therefore, when performing long-endurance missions, the system's navigation accuracy will gradually decrease, and it may even lose its navigation capability completely. Summary of the Invention

[0004] The main objective of this application is to provide a combined navigation system, method, aircraft, and computer-readable storage medium, aiming to solve the technical problem of how to provide a reliable absolute position reference for a purely visual / inertial combined navigation system in a complex electromagnetic environment, and avoid insufficient navigation accuracy.

[0005] To achieve the above objectives, this application provides a combined navigation system, the combined navigation system comprising: A visual / inertial navigation module is used to generate relative positioning information based on visual positioning data and inertial data; wherein, the relative positioning information accumulates over time and generates drift error; An anti-jamming receiver is used to receive satellite signals, suppress suppression jamming signals and deception jamming signals in the satellite signals, and output absolute positioning information; A fusion processing module is used to correct the relative positioning information based on the absolute positioning information and output navigation parameters to suppress the drift error.

[0006] In one embodiment, the anti-jamming receiver includes: Antenna array, the antenna array being used to receive satellite signals; The signal processing unit is configured to adaptively filter the satellite signal to suppress the suppression interference signal from at least one direction; perform at least one of carrier-to-noise ratio anomaly monitoring, Doppler frequency shift verification, pseudorange consistency comparison, and navigation message encryption authentication to identify and eliminate the spoofing interference signal; and perform calculations on the satellite signal after suppressing the suppression interference signal and eliminating the spoofing interference signal to output the absolute positioning information.

[0007] In one embodiment, the visual / inertial navigation module includes: An image acquisition unit is used to acquire measured images of the ground scene; A visual matching unit is used to visually match the measured image with a preset reference image to obtain the visual positioning data; wherein, the reference image includes ground images with pre-acquired geographic coordinate information in different seasons and at different times.

[0008] In one embodiment, the step of visually matching the measured image with a preset reference image to obtain the visual positioning data includes: Determine the relative position of the measured image within the reference image; Based on the relative position, the geographic coordinate information, and the current attitude angle of the aircraft, the spatial coordinate parameters of the aircraft are calculated by inverse spatial coordinate calculation and used as the visual positioning data.

[0009] In one embodiment, the image acquisition unit includes an infrared imager with a wavelength range of 8 to 12 micrometers.

[0010] In one embodiment, the vision / inertial navigation module includes a MEMS inertial measurement unit for measuring the angular motion and linear acceleration of the aircraft to output the inertial data.

[0011] In one embodiment, the fusion processing module is further configured to: When both the visual positioning data and the absolute positioning information are valid, a visual / inertial / satellite combined mode is adopted; When the visual positioning data is valid but the absolute positioning information is invalid, a visual / inertial combination mode is adopted. If the visual positioning data is invalid but the absolute positioning information is valid, a satellite / inertial combination mode is adopted. If both the visual positioning data and the absolute positioning information are invalid, a pure inertial mode is used.

[0012] In addition, to achieve the above objectives, this application also provides an aircraft that includes the integrated navigation system described above.

[0013] Furthermore, to achieve the above objectives, this application also provides a combined navigation method, which is applied to the aircraft described above, comprising: Relative positioning information is generated based on visual positioning data and inertial data; wherein, the relative positioning information accumulates over time and generates drift error; Receive satellite signals, suppress suppression interference signals and deception interference signals in the satellite signals, and output absolute positioning information; The relative positioning information is corrected based on the absolute positioning information, and navigation parameters are output to suppress the drift error.

[0014] In addition, to achieve the above objectives, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the combined navigation method described above.

[0015] This application proposes a combined navigation system, method, aircraft, and computer-readable storage medium. By configuring an anti-jamming receiver with jamming suppression and deception jamming capabilities within the combined navigation system, it can continuously and stably output absolute positioning information in complex electromagnetic environments such as urban electromagnetic noise, industrial interference, or electronic warfare attacks where ordinary satellite receivers cannot operate. This absolute positioning information is used by the fusion processing module as a global observation to continuously correct the relative positioning information generated by the visual / inertial navigation module, thereby fundamentally suppressing drift errors that accumulate over time and distance. When an aircraft adopts this combined navigation system, the position error of long-endurance, long-distance flight missions can be significantly reduced (e.g., the drift rate can be reduced from 1%–2% of the flight distance to below 0.1%). Simultaneously, the anti-jamming receiver can also suppress deception jamming signals, thereby preventing malicious signal hijacking and ensuring aircraft safety. This combined navigation system enhances its robustness across all scenarios through multi-source redundancy, overcoming the problem of insufficient navigation accuracy caused by the lack of an absolute position reference in traditional pure visual / inertial navigation systems under satellite denial or interference conditions, significantly improving the mission reliability and survivability of the aircraft in complex electromagnetic environments. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only a part of the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an integrated navigation system provided in an embodiment of this application; Figure 2 This application provides a schematic diagram of the structure of an anti-interference receiver in an integrated navigation system. Figure 3 A schematic diagram of the structure of a visual / inertial navigation module in an integrated navigation system provided in this application embodiment; Figure 4 A schematic diagram illustrating the principle of a visual matching and positioning process involved in an integrated navigation system provided in this application embodiment; Figure 5 A schematic diagram of the structure of an aircraft provided in this application embodiment; Figure 6 This is a flowchart illustrating a combined navigation method provided in an embodiment of this application.

[0018] The realization of the objectives, functional features and advantages of the embodiments of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0019] Explanation of icon numbers: 10. Visual / Inertial Navigation Module; 20. Anti-interference Receiver; 30. Fusion Processing Module; 201. Antenna Array; 202. Signal Processing Unit; 101. Image Acquisition Unit; 102. Visual Matching Unit; 1001. Processing Device; 1002. Read-Only Memory; 1003. Storage Device; 1004. Random Access Memory; 1005. Bus; 1006. Input / Output Interface; 1007. Input Device; 1008. Output Device; 1009. Communication Device. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the embodiments of this application.

[0021] When aircraft perform missions in environments with signal rejection or interference, they typically employ a visual / inertial integrated navigation system to achieve autonomous positioning and navigation. This system obtains visual positioning data by comparing images acquired by a downward-looking camera with pre-stored maps in real time, and combines this with inertial navigation data for integrated navigation, thus outputting navigation parameters such as speed, position, and attitude.

[0022] However, a pure vision / inertial navigation system is a relative measurement system. In complex electromagnetic environments, the ordinary satellite receivers configured in this system are prone to losing lock and are more susceptible to being hijacked by spoofed signals. They cannot provide a reliable absolute position reference for the system. As the flight time and distance increase, the system's position and heading errors will continue to accumulate, and the drift rate can typically reach 1% to 2% of the travel distance. After flying 10km, the position error can reach 100 to 500m. When a pure vision / inertial navigation system is running for a long time, the attitude angle error will increase exponentially with time. After 30 minutes, the heading error can exceed 15°, and the system will completely lose its navigation capability.

[0023] Based on this, embodiments of this application provide a combined navigation system, method, aircraft, and computer-readable storage medium. By configuring an anti-jamming receiver with the ability to suppress and deceptive interference within the combined navigation system, it can continuously and stably output absolute positioning information in complex electromagnetic environments such as urban electromagnetic noise, industrial interference, or electronic warfare attacks, where ordinary satellite receivers cannot operate. This absolute positioning information is used by the fusion processing module as a global observation to continuously correct the relative positioning information generated by the visual / inertial navigation module, thereby fundamentally suppressing drift errors that accumulate over time and distance. When an aircraft uses this combined navigation system, the position error for long-endurance, long-distance flight missions can be significantly reduced (e.g., the drift rate can be reduced from 1%–2% of the flight distance to below 0.1%). Simultaneously, the anti-jamming receiver can also suppress deceptive interference signals, thereby preventing malicious signal hijacking and ensuring the safety of the aircraft. This integrated navigation system enhances robustness across all scenarios through multi-source redundancy, overcoming the problem of insufficient navigation accuracy caused by the lack of absolute position reference in traditional pure vision / inertial navigation systems under satellite denial or interference environments. It significantly improves the mission reliability and survivability of aircraft in complex electromagnetic environments.

[0024] The integrated navigation system, method, aircraft, and computer-readable storage medium provided in the embodiments of this application are specifically described through the following embodiments. First, the integrated navigation system in the embodiments of this application is described.

[0025] This application provides a combined navigation system, referring to... Figure 1 , Figure 1 This is a schematic diagram of a combined navigation system provided in an embodiment of this application. This combined navigation system can be applied to aircraft, such as... Figure 1 As shown, the integrated navigation system provided in this embodiment includes: The visual / inertial navigation module 10 is used to generate relative positioning information based on visual positioning data and inertial data; wherein, the relative positioning information accumulates over time and generates drift error. Anti-jamming receiver 20 is used to receive satellite signals, suppress suppression jamming signals and deception jamming signals in the satellite signals, and output absolute positioning information; The fusion processing module 30 is used to correct the relative positioning information based on the absolute positioning information and output navigation parameters to suppress drift error.

[0026] In this embodiment, relative positioning information refers to the information output by the visual / inertial navigation module 10 that characterizes the changes in the position and attitude of the aircraft relative to a certain initial point or historical trajectory. Because inertial data has zero bias, visual positioning data has matching errors, and the visual / inertial navigation module 10 lacks continuous calibration with an external absolute reference, the relative positioning information accumulates and generates increasing drift errors over time and distance. For example, an aircraft navigating solely based on this relative positioning information may experience a position drift error of 100m to 500m after flying 10km.

[0027] In this embodiment, suppressing interference signals refers to malicious interference that prevents the satellite receiver from properly capturing and tracking satellite signals by emitting high-power noise or noise-like signals. Deceptive interference signals refer to malicious interference that induces the satellite receiver to output incorrect positioning results by forging or forwarding satellite signals. Absolute positioning information refers to the positioning result output by the anti-interference receiver 20, which has definite latitude and longitude (or equivalent coordinates) in the geographic coordinate system. It originates from GNSS (Global Navigation Satellite System) and has the absolute reference characteristic that does not accumulate errors over time or distance. Therefore, absolute positioning information can provide a global observation reference for relative positioning information. As an example, absolute positioning information can be the meter / centimeter-level absolute position output by the anti-jamming receiver 20, which can be used as the global observation value of the visual / inertial navigation module 10 to reduce the 1%~2% drift rate of pure visual / inertial navigation to below 0.1%, and control the position error of the aircraft equipped with this integrated navigation system within 10m after flying 10km; the high-precision time reference of satellite timing can calibrate the time synchronization error between the IMU (Inertial Measurement Unit) and the camera in the visual / inertial navigation module 10, and eliminate the system error caused by synchronization deviation.

[0028] In this embodiment, the fusion processing module 30 can use the absolute positioning information as a global observation to correct the relative positioning information and output the corrected navigation parameters (including position, velocity, and attitude), thereby suppressing drift errors. As an example, the fusion processing module 30 can be implemented using platforms such as embedded processors, digital signal processors, or field-programmable gate arrays; this embodiment does not impose any limitations on this.

[0029] The integrated navigation system in this embodiment combines the anti-interference receiver 20 with the visual / inertial navigation module 10, which can fundamentally make up for the shortcomings of pure visual / inertial navigation, and at the same time build a robust multi-source redundant navigation architecture that can cover navigation in all scenarios.

[0030] Reference Figure 2 In some feasible embodiments, the anti-interference receiver 20 described above may include: Antenna array 201 is used to receive satellite signals; The signal processing unit 202 is used to adaptively filter the satellite signal to suppress suppression interference signals from at least one direction; perform at least one of carrier-to-noise ratio anomaly monitoring, Doppler frequency shift verification, pseudorange consistency comparison, and navigation message encryption authentication to identify and eliminate spoofing interference signals; and perform calculations on the satellite signal after suppressing and eliminating spoofing interference signals to output absolute positioning information.

[0031] In this embodiment, the antenna array 201 can be used to sense electromagnetic waves emitted by a satellite in space and output multiple received signals. The antenna array 201 can be an array composed of multiple antenna elements arranged in a certain geometric layout, such as a square array composed of four elements or a circular array composed of seven elements. This embodiment does not make specific limitations on this.

[0032] In this embodiment, the signal processing unit 202 is connected to the antenna array 201 and is mainly used to handle the following three tasks: First, it performs adaptive spatial filtering on the multiple received signals output by the antenna array 201. Adaptive spatial filtering is a signal processing technique that adjusts the weighting coefficients of the received signals of each array element to form nulls (i.e., gain minimum points) upwards from the interference signal while maintaining gain upwards from the satellite signal. Through this technique, the signal processing unit 202 can suppress suppression interference signals from at least one direction. For example, when there are three broadband suppression interference sources in different directions, the signal processing unit 202 can form nulls in the corresponding three directions, and the interference suppression capability can reach more than 80dB (based on a satellite signal input power of -130dBm). Second, it performs deception interference identification and elimination processing on the signal after spatial filtering. Specifically, this includes at least one of the following methods: Carrier-to-noise ratio (CNR) anomaly monitoring: The CNR of a real satellite signal fluctuates within a certain range, while spoofing signals, usually emitted from a single source, may exhibit abnormal consistency or regular changes. Monitoring the statistical characteristics of the CNR can identify abnormal signals; Doppler frequency shift verification: The Doppler frequency shift generated by the relative motion between the real satellite and the receiver conforms to the laws of satellite orbital dynamics, while the Doppler frequency shift of spoofing signals may not match this; Pseudorange consistency comparison: The pseudorange observations of different satellite signals should satisfy spatial geometric consistency, which spoofing signals may disrupt; Navigation message encryption authentication: Using navigation message authentication technologies such as BeiDou and Galileo, the digital signature or encrypted information of the navigation message is verified to directly identify spoofing signals that have not passed authentication. Through these methods, the signal processing unit 202 can identify and eliminate spoofing interference signals. Third, the satellite signal after interference suppression and spoofing interference elimination is processed, which may include steps such as acquisition, tracking, bit synchronization, frame synchronization, pseudorange measurement, and positioning calculation, ultimately outputting absolute positioning information.

[0033] As an example, in this embodiment, the anti-interference receiver 20 can be a high-precision positioning board launched for special application markets, which is designed for satellite navigation receivers in complex and strong electromagnetic countermeasure environments. Through CRPA (Controlled Reception Pattern Antenna) controllable beam antenna, adaptive filtering, and wideband signal design, its interference suppression capability is 15~30dB higher than that of ordinary receivers. Under the same interference power, when ordinary receivers lose lock, the anti-interference receiver 20 can still stably track satellite signals. The anti-interference receiver 20 can be designed in a compact, classic size, with physical dimensions of only 80mm × 66mm × 28mm, facilitating user integration and making it an ideal solution for high-precision, specialized, and miniaturized applications. Its core strength lies in its advanced digital spatial processing technology. By amplifying, converting, and digitizing the BDB1 and GPSL1 frequency signals, it identifies and processes various strong electromagnetic interference signals, sending out frequency signals with interference removed. The BDB1 and GPSL1 frequencies possess anti-interference capabilities, simultaneously resisting interference from three directions. The BDB1 and GPSL1 frequencies are also burn-in resistant. Taking the BDB1 and GPSL1 frequencies as examples, the technical specifications of the anti-interference receiver 20 are as follows: 1) Receiving frequency points: B1: 1561.098MHz±2.046MHz; L1: 1575.42MHz±1.023MHz.

[0034] 2) Anti-interference capability of BDB1 and GPSL1 frequencies: (a) It has the ability to resist interference signals such as broadband modulation, white noise, frequency sweep, pulse, and narrowband, and can resist interference from three directions simultaneously. It has the ability to prevent BDB1 and GPSL1 frequency spoofing signals, including asynchronous spoofing, synchronous spoofing, and repeater spoofing, and can output clean navigation signals. (b) Resistance to single broadband interference: ≥90dB (signal calculated at -130dBm); (c) Resistance to three broadband interferences: ≥80dB (signal calculated at -130dBm); (d) Anti-interference airspace range: azimuth 0~360°, elevation 30~90°, where the elevation angle is defined as the angle between the space vector of the anti-interference source and the anti-interference antenna and the horizontal, with the y-axis of the machine system as the elevation axis, counterclockwise direction is "+", and clockwise direction is "-".

[0035] 3) Output power: -60~-70dBm; Output standing wave ratio: ≤2.0.

[0036] 4) Power supply voltage: 20VDC (or voltage range of 12 to 32V); power consumption: ≤15W.

[0037] In related technologies, pure vision / inertial navigation systems are prone to failure in visual feature extraction and matching in scenarios with low texture (such as deserts and water surfaces), drastic lighting changes, or motion blur, resulting in unusable visual positioning data and system degradation into pure inertial estimation, with drift errors rapidly amplified. Therefore, to improve the robustness and all-weather adaptability of visual positioning, referencing... Figure 3 In some feasible embodiments, the visual / inertial navigation module 10 described above may include: Image acquisition unit 101 is used to acquire measured images of the ground scene; The visual matching unit 102 is used to visually match the measured image with a preset reference image to obtain visual positioning data; wherein, the reference image includes ground images with geographic coordinate information pre-acquired in different seasons and at different times.

[0038] In this embodiment, the image acquisition unit 101 can be installed below the aircraft body, with its optical axis pointing to the ground. Its field of view covers a certain area of ​​the ground below the aircraft, thus enabling the acquisition of measured images of the ground scene below the aircraft. The reference image is a database of ground images of the flight area acquired in advance through aerial photography, satellite remote sensing, etc. It can include multiple versions of ground images acquired in advance in different seasons (such as spring, summer, autumn, and winter) and at different times (such as day and night) to adapt to matching requirements under different lighting and ground feature appearance conditions. The ground feature points in the reference image have been marked with accurate geographic coordinate information. The annotation of feature points can be performed after automatic feature detection of the reference image based on deep learning algorithms. The geographic coordinate information can be obtained through geographic information systems or high-precision surveying and mapping methods, and this embodiment does not impose any restrictions on this.

[0039] In some feasible embodiments, the visual matching unit 102 performs visual matching between the measured image and a preset reference image to obtain visual positioning data. The specific method may include: determining the relative position of the measured image in the reference image; and calculating the spatial coordinate parameters of the aircraft based on the relative position, geographic coordinate information and the current attitude angle of the aircraft, as visual positioning data.

[0040] In this embodiment, the visual matching unit 102 can determine the relative position of the measured image in the reference image using a feature-point-based image matching algorithm. This image matching algorithm can involve Scale Invariant Feature Transform (SIFT), Accelerated Robust Feature Transform (SURF), or a deep learning-based feature matching network. Taking deep learning as an example, feature points in the reference image can be pre-annotated and trained to make the algorithm more robust to changes in illumination, seasonal changes, and scale scaling. After the measured image is input, its feature descriptors can be extracted based on the algorithm and compared with the feature library in the reference image to determine the pixel coordinates or normalized coordinates of the center of the measured image in the reference image. The process of spatial coordinate inverse calculation can generally include: converting the coordinates of image points in the image coordinate system into line-of-sight vectors in the local horizontal coordinate system using the aircraft's attitude angles (pitch angle, roll angle, yaw angle); combining the aircraft's altitude information relative to the ground (which can be provided by a barometric altimeter or radar altimeter), and calculating the aircraft's position in the geographic coordinate system through the geometric intersection of the line of sight and the ground.

[0041] In this embodiment, the main purpose of performing visual matching is to solve the following problem: how to achieve spatial registration between two images that are acquired under different imaging conditions but belong to the same scene or region.

[0042] As an example, visual matching can be viewed as accurately locating the spatial position (i.e., its relative coordinates) of a smaller image within a larger image. The mathematical expression for this process is: L = g(I1(x,y), I2(x,y)); where I1(x,y) represents the larger reference image, also known as the baseline image; I2(x,y) represents the measured image, which is a ground-based image acquired by the UAV during flight. Understandably, the resolution of the measured image is usually much lower than that of the baseline image. g represents the image matching algorithm used, whose output is the spatial position of the measured image I2 within the baseline image I1, which can be denoted as the relative position data L. Figure 4 , Figure 4 The flowchart of the visual matching and localization process is shown. The image on the right, indicated by the arrow, is the reference image I1, and the dashed box represents the relative spatial position of the measured image I2 within the reference image I1. After acquiring the relative position data, the visual matching unit 102 can accurately solve for the space coordinate parameters of the aircraft by analyzing the inherent relationship between the measured image and the aircraft's attitude angles and using the spatial coordinate inverse calculation method.

[0043] Most visual / inertial navigation systems in related technologies use visible light cameras for image acquisition. While visible light cameras perform well in bright daylight, their image quality deteriorates drastically or even completely fails to capture images under conditions such as nighttime, dense fog, smoke, or strong backlighting, leading to visual matching failure and the system losing its visual positioning capability. Therefore, to overcome the shortcomings of visible light cameras in low-light and adverse weather conditions, in some feasible embodiments, the image acquisition unit 101 may include an infrared imager with a wavelength range of 8-12 micrometers.

[0044] In this embodiment, the infrared imager possesses functions such as acquiring scene image information around the clock and performing real-time non-uniformity correction based on usage conditions. Since 8 to 12 micrometers falls within the long-wave infrared band, which primarily receives the thermal radiation of ground objects themselves and does not rely on external light sources, the infrared imager in this embodiment can still obtain ground thermal radiation images with sufficient contrast even in complete darkness, under smog, or with drastic changes in lighting. For example, during nighttime patrols, targets such as buildings, roads, and water bodies exhibit clear outlines and textures due to differences in thermal radiation, providing reliable feature information for visual matching.

[0045] As an example, the infrared imager can employ an uncooled long-wave infrared imaging core with a detector array of 640×512 pixels, a pixel size of 12μm, a field of view of 96°×77°, and an image output frame rate of 25 frames per second, to balance imaging resolution, coverage, and real-time requirements. It is understood that the specific performance parameters described above are merely a feasible example, and in practical applications, they can be flexibly adjusted according to the actual flight mission and platform payload capacity; this embodiment does not impose any limitations on this.

[0046] The inertial data in the vision / inertial navigation module 10 can be sourced from an inertial measurement unit (IMU). However, traditional high-precision IMUs (such as fiber optic gyroscopes and laser gyroscopes) are large and expensive, making them difficult to widely apply on small and medium-sized UAV platforms. Lower-cost traditional inertial devices, on the other hand, suffer from poor zero-bias stability and insufficient long-term accuracy. Therefore, to achieve a balance between cost, size, and accuracy, in some feasible embodiments, the vision / inertial navigation module 10 may also include a MEMS inertial measurement unit. The MEMS inertial measurement unit measures the angular motion and linear acceleration of the aircraft to output inertial data.

[0047] In this embodiment, MEMS refers to Microelectromechanical Systems. The MEMS inertial measurement unit may include a high-performance three-axis MEMS gyroscope and a three-axis MEMS accelerometer. The MEMS gyroscope senses the angular motion of the aircraft based on the Coriolis effect and outputs a three-axis angular rate; the MEMS accelerometer senses the linear acceleration of the aircraft and outputs a three-axis specific force. By integrating the three-axis angular rate and the three-axis specific force, the attitude, velocity, and position changes of the aircraft can be obtained as inertial data.

[0048] The MEMS inertial measurement units undergo full-temperature-range calibration and error compensation before leaving the factory, including zero-point error compensation, scale factor error compensation, non-orthogonal error compensation, and acceleration-related error term compensation, thereby maintaining high measurement accuracy over a wide temperature range of -40℃ to +85℃. Although a single MEMS inertial measurement unit will still accumulate errors when operating independently for a long time, in the integrated navigation system provided in this embodiment, its drift can be continuously corrected by the absolute positioning information of the anti-interference receiver 20. Therefore, the accuracy of the MEMS device fully meets the system requirements, while also taking into account the advantages of miniaturization, low cost, and low power consumption.

[0049] As an example, the parameters and technical specifications of the MEMS inertial measurement unit can be set with reference to Table 1 below. It is understood that the parameters and technical specifications provided in Table 1 are only an example and can be flexibly adjusted according to actual needs in practical applications. This embodiment does not impose any restrictions on this.

[0050] Table 1

[0051] Traditional single-mode navigation systems have limitations in adaptability to different flight scenarios. For example, when satellite signals are suddenly interfered with, satellite-dependent systems immediately fail; when visual features are lost due to environmental changes, pure vision systems drift rapidly. The lack of a flexible multi-source collaborative switching mechanism will lead to interruptions or discontinuities in navigation information. Therefore, to address these issues, in some feasible embodiments, the aforementioned fusion processing module 30 can also be used to: employ a visual / inertial / satellite combined mode when both visual positioning data and absolute positioning information are valid; employ a visual / inertial combined mode when visual positioning data is valid but absolute positioning information is invalid; employ a satellite / inertial combined mode when visual positioning data is invalid but absolute positioning information is valid; and employ a pure inertial mode when both visual positioning data and absolute positioning information are invalid.

[0052] In this embodiment, the fusion processing module 30 is configured to perform multi-mode autonomous switching based on data validity, and the specific logic is as follows: Visual / Inertial / Satellite Combined Mode: This mode is used when both visual positioning data and absolute positioning information are deemed valid. In this mode, the system leverages the maximum advantages of each sensor. Absolute positioning information serves as a global observation to continuously correct drift in relative positioning information, visual positioning provides high-frequency position updates, and inertial measurement provides high-frequency attitude and acceleration information, achieving optimal navigation accuracy.

[0053] Visual / Inertial Combined Mode: This mode is used when visual positioning data is valid but absolute positioning information is invalid (e.g., when the aircraft enters a strong electromagnetic suppression area and the anti-jamming receiver 20 cannot maintain signal lock). In this mode, the system relies on the absolute geographic coordinates provided by visual matching for positioning and correction, while inertial measurement provides inter-frame interpolation and smoothing.

[0054] Satellite / Inertial Combined Mode: Used when visual positioning data is invalid (e.g., flying over a low-texture desert at night with low infrared image contrast), but absolute positioning information is valid. In this mode, the anti-jamming receiver 20 provides an absolute reference, inertial measurement maintains attitude and high-frequency motion estimation, and the visual positioning module can be in sleep mode or continuously attempt to acquire the target.

[0055] Pure Inertial Mode: Used under extreme conditions where both visual positioning data and absolute positioning information are invalid. In this mode, the system relies on the inertial measurement unit (IMU) for short-term dead reckoning. Simultaneously, the fusion processing module 30 can compensate for the reckoning results using error parameters such as inertial sensor zero bias and scaling factor estimated from historical moments, thus slowing down the rate of error divergence. Once any sensor becomes effective again, the system immediately re-enters the combined mode within a preset time (e.g., within 3 seconds).

[0056] The aforementioned mode switching is based on the determination of "data validity," which can be comprehensively judged through multiple means. For example, the validity of visual positioning data can be evaluated by indicators such as the number of matching feature points, the proportion of interior points, and reprojection error; the validity of absolute positioning information can be evaluated by indicators such as carrier-to-noise ratio, tracking loop lock status, positioning solution residual, and protection level. The fusion processing module 30 can monitor the output indicators of each sensor in real time and automatically complete the mode switching according to preset thresholds and logic without external command intervention, thereby ensuring the continuity and robustness of the aircraft's navigation function in complex dynamic environments.

[0057] As an example, based on a three-level redundant architecture consisting of "anti-interference receiver (absolute positioning) + visual positioning (relative positioning) + inertial navigation (high dynamic blind spot compensation)," it can support mode switching in at least the following environments: 1) Open environment: Anti-interference receiver is the primary component, with visual navigation assisting in correction, achieving optimal accuracy; 2) Interference / denial environment: Visual / inertial navigation provides short-term blind spot compensation, while the anti-interference receiver continuously attempts to acquire signals, correcting drift immediately after the interference disappears; 3) High dynamic scenario: Inertial navigation provides high-frequency attitude, while the receiver corrects low-frequency errors, balancing dynamic response and long-term accuracy.

[0058] The integrated navigation system provided in this embodiment can reduce the impact of visual anomalies on the fusion results through data validity pre-verification (such as speed change threshold check), robust filtering (Huber-M estimator corrects noise covariance), and multi-source cross-validation (combined with air pressure, altitude, and other auxiliary judgments), ensuring that the combined mode continues to be available at >95% in scenarios such as changes in lighting and slight occlusion.

[0059] Furthermore, this application also provides an aircraft that includes the integrated navigation system described in any of the above embodiments.

[0060] The aircraft in this embodiment can be a multi-rotor UAV, a fixed-wing UAV, a vertical takeoff and landing UAV, an unmanned helicopter, or other types of aircraft. The integrated navigation system can be installed inside or outside the aircraft fuselage and connected to the flight control system, power system, and mission payload system via electrical interfaces.

[0061] refer to Figure 5 It shows a structural schematic diagram of an aircraft suitable for implementing the embodiments of this application. Figure 5 The aircraft shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments described in this application. Figure 5As shown, the aircraft may include a processing unit 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory 1002 or a program loaded from a storage device 1003 into a random access memory 1004. The random access memory 1004 also stores various programs and data required for aircraft operation. The processing unit 1001, the read-only memory 1002, and the random access memory 1004 are interconnected via a bus 1005. An input / output interface 1006 is also connected to the bus. Typically, the following systems can be connected to the input / output interface 1006: input devices 1007 including, for example, a touchscreen, touchpad, keyboard, mouse, image sensor, microphone, accelerometer, gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; storage devices 1003 including, for example, magnetic tape, hard disk, etc.; and communication devices 1009. The communication device 1009 allows the aircraft to communicate wirelessly or wiredly with other devices to exchange data. Although the diagram shows an aircraft with various systems, it should be understood that it is not required to implement or have all of the systems shown, and it is possible to implement or have more or fewer systems instead.

[0062] Specifically, according to the embodiments disclosed in this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, an embodiment of this application provides a computer program product including a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 1003, or installed from read-only memory 1002. When the computer program is executed by processing device 1001, it performs the functions defined in the methods of the embodiments disclosed in this application.

[0063] The beneficial effects of the aircraft provided in this application are the same as those of the integrated navigation system provided in the above embodiments, and other technical features of the integrated navigation system in this aircraft are the same as those disclosed in the above embodiments, and will not be repeated here.

[0064] Furthermore, embodiments of this application also provide a combined navigation method, referring to... Figure 6 , Figure 6 This is a flowchart illustrating an integrated navigation method provided in an embodiment of this application. This integrated navigation method can be applied to aircraft, such as... Figure 6 As shown, the combined navigation method provided in this embodiment includes steps S10 to S30.

[0065] Step S10: Generate relative positioning information based on visual positioning data and inertial data; wherein, the relative positioning information accumulates over time and generates drift error; Step S20: Receive satellite signals, suppress jamming and deception signals in the satellite signals, and output absolute positioning information; Step S30: Correct the relative positioning information based on the absolute positioning information and output navigation parameters to suppress drift error.

[0066] The integrated navigation method provided in this embodiment belongs to the same technical concept as the integrated navigation system in the aircraft provided in the above embodiments. Technical details not described in detail in this embodiment can be found in any of the above embodiments and will not be repeated here. Furthermore, this embodiment has the same beneficial effects as the above embodiments.

[0067] Furthermore, embodiments of this application also provide a computer-readable storage medium, which may be a non-volatile computer-readable storage medium, on which a computer program is stored, and which, when executed by a processor, implements the combined navigation method provided in any of the above embodiments.

[0068] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0069] The aforementioned computer-readable storage medium may be included in an electronic device or may exist independently without being assembled into an electronic device.

[0070] The aforementioned computer-readable storage medium may carry one or more programs, which, when executed by a processor, enable the processor to implement the aforementioned combined navigation method.

[0071] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a Local Area Network (LAN) or a Wide Area Network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0072] The computer-readable storage medium provided in this embodiment stores computer-readable program instructions (i.e., computer program) for executing the above-described integrated navigation method. The beneficial effects of the computer-readable storage medium provided in this embodiment are the same as those of the integrated navigation method provided in the above embodiments, and will not be repeated here.

[0073] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0074] Furthermore, in the embodiments of this application, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B.

[0075] In the embodiments of this application, unless otherwise expressly specified and limited, the terms "connection" and "fixed" should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0076] It should also be understood that references to "one embodiment" or "some embodiments" in the specification of embodiments of this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0077] It should be noted that the technical solutions of the various embodiments of this application can be combined with each other, but only if they are implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the embodiments of this application.

[0078] The above are merely optional embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A combined navigation system applied to an aircraft, characterized in that, The integrated navigation system includes: A visual / inertial navigation module is used to generate relative positioning information based on visual positioning data and inertial data; wherein, the relative positioning information accumulates over time and generates drift error; An anti-jamming receiver is used to receive satellite signals, suppress suppression jamming signals and deception jamming signals in the satellite signals, and output absolute positioning information; A fusion processing module is used to correct the relative positioning information based on the absolute positioning information and output navigation parameters to suppress the drift error.

2. The integrated navigation system as described in claim 1, characterized in that, The anti-interference receiver includes: Antenna array, the antenna array being used to receive satellite signals; The signal processing unit is configured to adaptively filter the satellite signal to suppress the suppression interference signal from at least one direction; perform at least one of carrier-to-noise ratio anomaly monitoring, Doppler frequency shift verification, pseudorange consistency comparison, and navigation message encryption authentication to identify and eliminate the spoofing interference signal; and perform calculations on the satellite signal after suppressing the suppression interference signal and eliminating the spoofing interference signal to output the absolute positioning information.

3. The integrated navigation system as described in claim 1, characterized in that, The visual / inertial navigation module includes: An image acquisition unit is used to acquire measured images of the ground scene; A visual matching unit is used to visually match the measured image with a preset reference image to obtain the visual positioning data; wherein, the reference image includes ground images with pre-acquired geographic coordinate information in different seasons and at different times.

4. The integrated navigation system as described in claim 3, characterized in that, The step of visually matching the measured image with a preset reference image to obtain the visual positioning data includes: Determine the relative position of the measured image within the reference image; Based on the relative position, the geographic coordinate information, and the current attitude angle of the aircraft, the spatial coordinate parameters of the aircraft are calculated by inverse spatial coordinate calculation and used as the visual positioning data.

5. The integrated navigation system as described in claim 3, characterized in that, The image acquisition unit includes an infrared imager with a wavelength range of 8 to 12 micrometers.

6. The integrated navigation system as described in claim 1, characterized in that, The vision / inertial navigation module includes a MEMS inertial measurement unit, which measures the angular motion and linear acceleration of the aircraft to output the inertial data.

7. The integrated navigation system as described in claim 1, characterized in that, The fusion processing module is also used for: When both the visual positioning data and the absolute positioning information are valid, a visual / inertial / satellite combined mode is adopted; When the visual positioning data is valid but the absolute positioning information is invalid, a visual / inertial combination mode is adopted. If the visual positioning data is invalid but the absolute positioning information is valid, a satellite / inertial combination mode is adopted. If both the visual positioning data and the absolute positioning information are invalid, a pure inertial mode is used.

8. An aircraft, characterized in that, The aircraft includes the integrated navigation system as described in any one of claims 1 to 7.

9. A combined navigation method, characterized in that, The integrated navigation method is applied to the aircraft as described in claim 8, comprising: Relative positioning information is generated based on visual positioning data and inertial data; wherein, the relative positioning information accumulates over time and generates drift error; Receive satellite signals, suppress suppression interference signals and deception interference signals in the satellite signals, and output absolute positioning information; The relative positioning information is corrected based on the absolute positioning information, and navigation parameters are output to suppress the drift error.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the integrated navigation method as described in claim 9.

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