Task scheduling method and system for a combined navigation device

Abstract

The application discloses a task scheduling method and system of a combined navigation device. The method comprises the following steps: collecting data through a plurality of inertial measurement units, and adopting a plurality of threads to compensate the collected data; pre-processing the compensated data, and performing alignment based on the pre-processed data; after the alignment, adopting a plurality of task modules to perform a strapdown task scheduling on the combined navigation device. The application solves the technical problem of low efficiency caused by the serial processing of single-core working navigation logic in the related art.

Description

Technical Field

[0001] This application relates to the field of navigation, and more specifically, to a task scheduling method and system for a combined navigation device. Background Technology

[0002] Modern satellite navigation systems have long time intervals between two positioning operations, and each positioning requires more than 10 minutes of tracking, making it impossible to continuously provide UAV location information. Therefore, they are often combined with inertial navigation systems.

[0003] Using a satellite global positioning system enables UAVs to obtain real-time position and speed information in any region. However, the single-core navigation logic with serial processing results in low navigation efficiency.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This application provides a task scheduling method and system for a combined navigation device, which at least solves the technical problem of low efficiency caused by serial processing of single-core working navigation logic.

[0006] According to one aspect of the embodiments of this application, a task scheduling method for a combined navigation device is provided, comprising: acquiring data through multiple inertial measurement units and using multi-threading to compensate the acquired data; preprocessing the compensated data and aligning it based on the preprocessed data; and after alignment, using a multi-task module to perform strapdown task scheduling for the combined navigation device.

[0007] According to another aspect of the embodiments of this application, a task scheduling system for a combined navigation device is also provided, comprising: a data acquisition module configured to acquire data through multiple inertial measurement units and to perform compensation processing on the acquired data using multi-threading; an alignment module configured to preprocess the compensated data and perform alignment based on the preprocessed data; and a scheduling module configured to perform strapdown task scheduling for the combined navigation device after alignment using a multi-task module.

[0008] In this embodiment, data is acquired through multiple inertial measurement units, and multi-threading is used to compensate the acquired data. The compensated data is preprocessed, and alignment is performed based on the preprocessed data. After alignment, a multi-task module is used to perform strapdown task scheduling on the integrated navigation device, thereby solving the technical problem of low efficiency caused by the single-core working navigation logic of serial processing. Attached Figure Description

[0009] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0010] Figure 1 This is a flowchart of a task scheduling method for a combined navigation device according to an embodiment of this application;

[0011] Figure 2A This is a flowchart of an initialization method according to an embodiment of this application;

[0012] Figure 2B This is a flowchart of a parallel processing method according to an embodiment of this application;

[0013] Figure 2C This is a schematic diagram of a geographic coordinate system according to an embodiment of this application;

[0014] Figure 2D This is a schematic diagram of a loosely coupled structure according to an embodiment of this application;

[0015] Figure 3 This is a flowchart of a Kalman filter error correction method according to an embodiment of this application;

[0016] Figure 4 This is a schematic diagram of the strapdown inertial measurement unit system according to an embodiment of this application;

[0017] Figure 5 This is a hardware design circuit diagram of an inertial measurement component according to an embodiment of this application;

[0018] Figure 6 This is a hardware design circuit diagram of a navigation computer according to an embodiment of this application;

[0019] Figure 7 This is a hardware design circuit diagram of a secondary power supply module according to an embodiment of this application;

[0020] Figure 8 This is a hardware design circuit diagram of a satellite receiver according to an embodiment of this application. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0023] According to embodiments of this application, a task scheduling method for a combined navigation device is provided, such as... Figure 1 As shown, the method includes:

[0024] Step S 102: Data is acquired through multiple inertial measurement units, and multi-threading is used to compensate the acquired data.

[0025] First, initialize at least one of the following: system variables, stored information, message information, stored parameters, user parameters, compensation parameters, and configuration parameters.

[0026] Next, the acceleration and angular velocity information of the UAV are acquired through the strapdown inertial measurement unit, and multi-threading is used to compensate for the collected data.

[0027] Step S 104: Preprocess the compensated data and perform alignment based on the preprocessed data;

[0028] Step S106: After alignment, a multi-task module is used to perform strapdown task scheduling on the combined navigation device.

[0029] First, after acquiring the acceleration and angular velocity information of the UAV through a strapdown inertial measurement unit, attitude calculation is performed using the quaternion method based on the angular velocity information to obtain the attitude angles of the carrier. Specifically, quaternions are used to describe the attitude information, and the relationship between the transformation formula from the projectile coordinate system to the geographic coordinate system and the quaternions is determined based on the description. Using the angular velocity increment, the quaternions describing the attitude information are solved based on the determined transformation formula and the relationship between the quaternions. Based on the solved quaternions, attitude calculation is performed to obtain the attitude angles of the carrier.

[0030] Next, based on the acceleration information, a strapdown calculation is performed to obtain the velocity and position information of the vehicle. Specifically, based on the rate of change of ground speed in the inertial coordinate system, the specific force vector in the acceleration information, and the Earth's rotational angular velocity, the rate of change of ground speed in the navigation coordinate system is determined; based on the rate of change of ground speed in the navigation coordinate system, the navigation equation is determined, and based on the navigation equation, the components of the vehicle's velocity along true north, east, and local perpendicular directions in the navigation coordinate system are determined. For example, based on the rate of change of the vehicle's longitude and latitude, the rotational angular rate of the geographic coordinate system relative to the Earth-fixed coordinate system is determined; based on the rotational angular rate, the local gravity vector of the vehicle is determined; based on the angular deviation of the local gravity vector direction relative to the local perpendicular direction caused by gravity anomalies, the current latitude, current longitude, and current altitude above the Earth's surface, and the local gravity vector, the components of the vehicle's velocity along true north, east, and local perpendicular directions in the navigation coordinate system are determined.

[0031] The system receives satellite differential correction information transmitted by the ground station at a preset frequency and uses the satellite differential correction information to correct the pose information.

[0032] First, based on the satellite differential correction information, a Kalman filter is used to estimate the errors in position, velocity, and attitude. Specifically, the position, velocity, and attitude from the navigation solution of the navigation satellite system are input into the Kalman filter as measurement information, serving as initial estimates. During the prediction phase, the Kalman filter linearizes the initial estimates and determines the error covariance based on the linearized initial estimates. The Kalman gain is then determined based on the error covariance, and the error covariance is recalculated based on the Kalman gain. Finally, the errors in position, velocity, and attitude calculated by the strapdown system are estimated based on the recalculated error covariance.

[0033] Then, the pose information is corrected based on the estimated error.

[0034] Finally, the drone is navigated based on the corrected pose information.

[0035] In this embodiment, a multi-tasking mode is added to facilitate program maintenance and upgrades, and the degree of software modularity is improved, making it suitable for parallel development and thus improving efficiency.

[0036] Furthermore, in this embodiment, satellite differential correction information transmitted by the ground station at a preset frequency is received, and the pose information is corrected using the satellite differential correction information; based on the corrected pose information, the UAV is navigated, thereby improving the accuracy of navigation.

[0037] Example 2

[0038] According to an embodiment of this application, a task scheduling method for a combined navigation device is also provided, the method comprising:

[0039] Step S202, Initialization.

[0040] Specifically, such as Figure 2A As shown, after the inertial navigation system is powered on, it automatically starts initialization and self-test, checking the working status of the device's gyroscope, accelerometer and navigation computer. The self-test timeout is 10 seconds.

[0041] The inertial navigation system (INS) feeds back its current status to the integrated control computer every 5ms, updating the result word, INS operating status, navigation time, software version number, etc. At the start of the INS self-test, the "result word" in the data packet is updated to "self-test in progress"; after the self-test is completed, the "result word" is updated to "self-test normal" or "self-test abnormal", and the INS continues to periodically report data packets, waiting for the next command from the integrated control computer.

[0042] The integrated control computer determines the inertial navigation system initialization and self-test results based on the result words. If the inertial navigation system still has not completed the self-test after 10 seconds of power supply, it is determined that the self-test timeout is abnormal.

[0043] Step S204, parallel processing.

[0044] Parallel processing of tasks, specifically as follows: Figure 2B As shown.

[0045] After receiving the alignment command and alignment data from the terminal control platform / test equipment, the integrated control computer sends an "alignment and alignment command" to the inertial navigation system (INS), which then responds to the command and begins alignment. Simultaneously, the integrated control computer forwards the ship's motherboard INS alignment and alignment data to the INS at 5ms intervals, with the data update determining the valid data based on the "reference INS frame count".

[0046] After receiving the instruction, the inertial navigation system (INS) enters the "normal alignment" or "fast alignment" branch according to the setup and alignment type, reports "binding in progress," and encapsulates the data according to the parameters after receiving 5 consecutive frames of reasonable binding data. If the binding conditions are not met for 2.5 seconds, it reports "binding abnormality." If an INS unit malfunctions during the binding process, or if binding data is not received for 1 second, or if the number of consecutive invalid reference information determinations is greater than or equal to 50, it reports "binding abnormality."

[0047] After the inertial navigation system (INS) is properly bound, it automatically enters the alignment process, entering either "Normal Alignment" or "Fast Alignment" depending on the current branch, and reporting "Alignment in Progress". During fast alignment, if a self-check anomaly occurs, no bound data is received for 1 consecutive second, or the number of consecutive invalid reference information determinations is greater than or equal to 50, a "Fast Alignment Anomaly" report is submitted; if at least one horizontal correction is performed based on the bound and alignment data, a "Fast Alignment Normal" report is submitted. During normal alignment, if at least 20 horizontal corrections are performed based on the bound and alignment data, a "Alignment Normal" report is submitted; if the INS malfunctions during this period, or no bound data is received for 1 consecutive second, or the number of consecutive invalid reference information determinations is greater than or equal to 50, an "Alignment Anomaly" report is submitted; the "Alignment and Calibration Accuracy" is clearly stated in the result message.

[0048] After the inertial navigation system (INS) is aligned correctly, it automatically enters the calibration state. During the calibration process, if the INS detects an abnormality, fails to receive binding data for 1 second consecutively, or has more than 50 consecutive invalid reference information entries, it will report a "calibration abnormality". The alignment and calibration accuracy will be specified in the "INS operating status word", including: normal alignment accuracy, fast alignment accuracy, and below fast alignment accuracy.

[0049] The integrated control computer starts timing from receiving the "alignment command" from the terminal control platform / test equipment. Normal alignment time should not exceed 3 minutes, and rapid alignment should not exceed 10 seconds.

[0050] The specific algorithm is as follows:

[0051] 1) Coordinate system design.

[0052] The navigation coordinate system adopts the North-Sky-East coordinate system. The origin of the coordinate system is taken at the center of mass of the aircraft, ox. n The axis points to the North Pole, oy n The axis is perpendicular to the local horizontal plane and points upwards, oz n The axis points east and ox n Shaft, oy n The axis follows the right-hand rule, such as... Figure 2C As shown.

[0053] The origin of the carrier coordinate system is at the center of mass of the spacecraft, ox b The axis is along the longitudinal axis of the aircraft, with the direction pointing towards the nose of the aircraft being positive. b The axis lies within the longitudinal symmetry plane of the aircraft and is perpendicular to ox. b The axis pointing upwards is positive, oz b Axis and ox b Shaft and oy b The shaft follows the right-hand rule and is fixedly connected to the carrier.

[0054] Using positive Euler, the true heading angle ψ can be obtained. NThe transformation relationship from the projectile coordinate system to the geographic coordinate system, directly described by the pitch angle θ and roll angle γ, is as follows:

[0055]

[0056] When using positive Euler coordinates, the pitch and roll angles of the geographic coordinate system and the vehicle coordinate system are defined in the same way, and the relationship between the yaw angle and the true heading angle is as follows:

[0057]

[0058] Where A represents the angular deviation.

[0059] In this embodiment, the coordinate system is transformed in the above manner, which can avoid the errors that exist during coordinate transformation, thereby making the subsequent navigation calculation more accurate.

[0060] 2) Attitude calculation.

[0061] This implementation uses the quaternion method, which uses four elements to describe all attitude information. The quaternion q can be represented as:

[0062] q=a+bi+cj+dk (1)

[0063] Where a, b, c, d are the real parts of the quaternion, and i, j, k are the imaginary units.

[0064] Let there be a vector v in the b system. b Its representation in the n-ary system is v n ,but:

[0065]

[0066] In the formula q * =a-bi-cj-dk is the complex conjugate of the quaternion q.

[0067] From the above formula, we can obtain Relationship with quaternions:

[0068]

[0069] Using quaternion attitude calculation, the following equations need to be solved:

[0070]

[0071] Where p = [0, ω] T ], This represents the differential form of a quaternion, where q represents the quaternion, and the component of the angular velocity ω is ω. x ω y ω z Equation (4) can also be expressed in matrix form:

[0072]

[0073] In the formula

[0074]

[0075] The solution quaternion is calculated using the angular increment, and its solution can be expressed as:

[0076]

[0077] Where, q k Let t represent the quaternion at time k. k The moment of integral calculation.

[0078] Substitute W, let

[0079]

[0080] The final solution is:

[0081]

[0082] In the formula, T is the system sampling period, and I is a 4x4 identity matrix.

[0083] Therefore, the attitude angle can be obtained by solving quaternions, as shown in the following formula:

[0084]

[0085] In the formula, matrix C is the same as equation (3).

[0086] In this embodiment, the attitude angle is calculated in the above manner, which makes the calculated attitude angle more accurate, thereby providing accurate basic data for subsequent navigation.

[0087] 3) Strapdown calculation.

[0088] The navigation equation can be expressed in the following form:

[0089]

[0090] Where r represents the position vector and f represents the specific force, the velocity is obtained by the first integration and the position is obtained by the second integration.

[0091]

[0092] Among them, v n This represents the velocity in the navigation coordinate system. For navigation systems operating on Earth using the local geographic coordinate system, the ground speed is expressed as... Its rate of change relative to the navigation coordinate system can be expressed by its rate of change in the inertial frame:

[0093]

[0094] in, v e Ground speed, ω en ω represents the angular rate of rotation of the navigation coordinate system relative to the Earth coordinate system. ie The angular rate of rotation of the Earth coordinate system relative to the inertial coordinate system is expressed as g1 = g - ω. ie ×[ω ie Substituting ×r] into equation (13), we get:

[0095]

[0096] The navigation equation can be expressed in the following form:

[0097]

[0098] The velocity components along true north, east, and the local perpendicular are: Among them, v N v E v D These represent the velocities along true north, east, and the local perpendicular, respectively. The angular rate of rotation of the Earth coordinate system relative to the inertial coordinate system. This represents the angular rate of rotation of the navigation coordinate system relative to the Earth coordinate system. Indicates ground speed.

[0099] f n It is a set of specific force vectors measured by three accelerometers, which, when decomposed into the local geographic reference coordinate system, are:

[0100] f n =[f N f E f D ] T (16)

[0101] It is the Earth's angular velocity of rotation in the local geographic coordinate system:

[0102]

[0103] in, The rate of rotation of the local geographic coordinate system relative to the Earth-fixed coordinate system, i.e., the rate of change, can be expressed as the rate of change of longitude and latitude as follows:

[0104]

[0105] make Where L represents latitude, we get:

[0106]

[0107] In equation (19), R0 is the Earth's radius; h is the height above the Earth's surface.

[0108] It is the local gravity vector, which is composed of the Earth's gravitational pull (g) and the centripetal acceleration (ω) caused by the Earth's rotation. ie ×ω ie It consists of ×R). Therefore, it can be written as:

[0109]

[0110] Where Ω represents the Earth's rotation angular rate, the navigation equation can be expressed in the following component form:

[0111]

[0112]

[0113]

[0114] In the formula: ξ and η are the angular deviations of the local gravity vector direction relative to the local vertical direction caused by gravity anomalies.

[0115] Latitude, longitude, and altitude above the Earth's surface are given by the following formulas:

[0116]

[0117]

[0118]

[0119] in, Representing the differential form of latitude, Representing the differential form of longitude, It represents the differential form of the height above the Earth's surface.

[0120] In this embodiment, when calculating the velocity information, not only latitude, longitude, and altitude above the Earth's surface are considered, but also the angular deviation of the local gravity vector direction relative to the local vertical direction caused by gravity anomalies is introduced, thereby making the calculated velocity information more accurate.

[0121] 4) Combined navigation.

[0122] The integrated navigation system consists of a micro-strappable inertial measurement unit (MSU) and a rover satellite receiver (GNSS). The GNSS is responsible for resetting the accumulated errors of the inertial navigation over a certain time period. A loosely coupled architecture is employed, where the estimated position, velocity, and attitude errors are used to correct the inertial navigation solution. The specific architecture is as follows: Figure 2D As shown.

[0123] The loosely coupled structure in this embodiment is a cascaded system. The navigation solution outputs position and velocity from GNSS as measurement information and inputs it into a Kalman filter. The Kalman filter is used to estimate the error of the strapdown solution. The specific process of the Extended Kalman Filter (EKF) method is as follows: Figure 3 As shown, the process includes the following steps: Step S302, establishing a system model and a measurement model; Step S304, inputting initial estimates; Step S306, performing linearization processing during the prediction phase and estimating the error covariance; Step S308, calculating the Kalman gain and re-estimating the error covariance based on the Kalman gain.

[0124] The main advantages of the loosely coupled integration provided in this embodiment are simplicity and redundancy. It can be used with any micro inertial measurement unit (i.e., strapdown inertial measurement unit) and GNSS device, and is particularly suitable for algorithm improvement applications. In the loosely coupled structure, there is an independent GNSS navigation solution available, which is separate from the combined navigation solution. There is also an independent micro inertial measurement unit navigation solution during open-loop micro inertial measurement unit correction execution, which supports basic parallel navigation solutions.

[0125] In the micro inertial measurement unit error model of this embodiment, the error model is based on a small misalignment angle. The influence of error factors is represented by a small perturbation, and the nonlinear differential equation of the micro inertial measurement unit error is derived. According to the error state equations of the micro inertial measurement unit and GNSS, the combined system state variables are composed of the error state variables of the micro inertial measurement unit and GNSS, which can be expressed by equation (27).

[0126]

[0127] in, Let F(t) represent the differential form of the system state variables, and let X represent the state transition matrix. (t) Let B(t) represent the system state vector, B(t) represent the control matrix, u(t) represent the control variables, G(t) represent the system noise driving matrix, and w(t) represent the system noise matrix.

[0128] The errors of the vehicle-mounted micro inertial measurement unit include the roll angle deviation δα in the X-axis direction and the pitch angle deviation δ in the Y-axis direction. β Z-axis yaw angle deviation δ γ Three speed errors δ VN δ VEδ VD and three position errors δL, δl, δh, δf x δfδ y δf z The acceleration deviations (m / s²) are for the X, Y, and Z axes, respectively. 2 ), δ ωx δ ωy δ ωz The gyroscope deviations (° / s) for the X-axis, Y-axis, and Z-axis are respectively expressed by the following formula (28):

[0129]

[0130] The state transition matrix F is obtained by simplifying the error model. (t) For (29):

[0131]

[0132]

[0133] Among them, F S-9×9 F represents the error of a 9×9 dimensional inertial navigation system. DCM-6×6 DCM represents a 6×6 directional cosine matrix. 3×3 This represents a 3×3 directional cosine matrix.

[0134] The attitude angle error is expressed by equation (31) through the relationship between the direction cosine matrix from the vehicle reference frame to the navigation reference frame and the error of the gyroscope.

[0135]

[0136] Where C represents the element of the direction cosine matrix.

[0137] The elements of the F matrix are represented by equations (32) to (43):

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150] Where R is the Earth's radius, V N V E V D The micro inertial measurement unit indicates the north, east, and ground-direction velocities, f. n f E f D This is the north, east, and ground force measurement of the MIMU. L is the latitude output by the micro inertial measurement unit, Ω is the Earth's rotational angular velocity, and the altitude is negligible relative to the Earth's radius, so the altitude is omitted for simplification.

[0151] The measurement model of the integrated system is embodied in matrix H, which links the measurement model to the filtering state. In this embodiment, the observation information is the velocity, position, and attitude of the GNSS system. The attitude includes yaw angle α and pitch angle β; GNSS cannot provide roll angle. The GNSS provides the vehicle's current position information, using a geographic reference frame as the navigation reference frame, with longitude L... G latitude G Height h G For parameters. GNSS provides vehicle speed information, using Cartesian velocity [V]. N V E V D As a GNSS velocity measurement.

[0152] The location provided by GNSS is the sum of the ground truth and error under geographic conditions, as shown in (44):

[0153]

[0154] Among them, L G Indicates latitude in a geographic coordinate system, l G h represents longitude in a geographic coordinate system. G L represents altitude in a geographic coordinate system. N N represents the latitude in the navigation coordinate system. N N represents the northward position error of the satellite receiver. E R represents the eastward position error of the satellite receiver. N h represents the lateral radius of curvature. N The altitude in the navigation coordinate system is represented by Nh, which is the astronomical position error of the satellite receiver. δL, δl, and δh are the position error measurements of the GNSS relative to the navigation reference system, as shown in (45):

[0155]

[0156] Among them, L I Indicates latitude in an inertial coordinate system, l I Indicates longitude in an inertial coordinate system, l G R represents longitude in a geographic coordinate system. M R represents the radius of curvature of the meridional plane. N P represents the lateral radius of curvature. GN P represents the northward position in the geographic coordinate system. GE P represents the eastward position in the geographic coordinate system. GD This indicates the Earth's orientation in the geographic coordinate system. The velocity measurement information of the micro inertial measurement unit is the sum of the true value in the navigation system and the corresponding velocity error; the GNSS velocity measurement information is the difference between the true value in the N-frame and the corresponding velocity measurement error. M N M E M D The velocity measurement error term of GNSS is represented by the component on the northeast coordinate axis. The velocity measurement is shown in equation (46):

[0157]

[0158] Among them, V IN V represents the northward velocity in the inertial coordinate system. GN V represents the northward velocity in the geographic coordinate system. IE V represents the eastward velocity in the inertial coordinate system. GE V represents the eastward velocity in the geographic coordinate system. ID V represents the ground velocity in the inertial coordinate system. GD M represents the ground velocity in the geographic coordinate system. N M represents the northward error velocity of the satellite receiver. E M represents the eastward error velocity of the satellite receiver. D δ represents the ground error velocity of the satellite receiver. VN δ represents the northbound velocity error component. VE δ represents the ground velocity error component. VD Let HV represent the ground velocity error component, HV represent the measurement matrix, X(t) represent the system state vector, and Vv(t) represent the measurement noise vector.

[0159] In the above formula The standard deviation of the velocity is represented by equation (47).

[0160]

[0161] Where HDOP represents the position precision factor. This represents the differential form of the standard deviation of the location.

[0162] The attitude measurement of the micro inertial measurement unit is expressed as the true value and corresponding attitude error in the navigation system, and the attitude measurement of GNSS is expressed as the true value and corresponding attitude error in the N system. The equations for the heading angle and pitch angle measurement are (48):

[0163]

[0164] in, Represents the attitude measurement equation. Represents the heading angle in the inertial coordinate system. Indicates the heading angle in the geographic coordinate system. Represents the pitch angle in the inertial coordinate system. Indicates the pitch angle in the geographic coordinate system. Let X(t) represent the attitude observation matrix, and X(t) represent the system state vector. This represents the measurement noise matrix.

[0165] The position, velocity, and attitude quantities (45)(46)(48) are combined and expressed as shown in Equation 49:

[0166]

[0167] Where Z represents the measurement equation, Z p(t) The equation for position measurement, Z v(t) Represents the equation for velocity measurement. The attitude measurement equation is represented by H. V H represents the velocity measurement matrix. P Represents the position measurement matrix. Represents the attitude measurement matrix, v p This indicates the position measurement error of the satellite receiver, v v X represents the satellite receiver velocity measurement error. k+1 V represents the estimated state of the system at time k+1, where k represents the current navigation solution time. k+1 Let H represent the measurement noise sequence at time k+1, and let H represent the measurement matrix. This refers to GNSS observation noise.

[0168] In this embodiment, the measurement equations of the combined system are established by using velocity, position and attitude errors, which is more suitable for the changes of dynamic systems than directly using state values.

[0169] 5) Initial alignment.

[0170] The system utilizes reference information measured by a satellite base station, including longitude, latitude, altitude, attitude angles, pitch angles, and heading angles. This reference information is then transmitted to the strapdown inertial measurement unit (SMU). Upon receiving the reference information, the SMU uses an established EKF filter, combined with its own inertial data and satellite data, to complete the transfer alignment under velocity and position matching. This achieves initial alignment at the UAV end.

[0171] This application solves the technical problems of large size and high cost of discrete inertial and satellite navigation systems in the prior art, and has the beneficial effects of small size and low cost.

[0172] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0173] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0174] Example 3

[0175] According to an embodiment of this application, a combined navigation system for an ultra-small unmanned aerial vehicle (UAV) is provided, including a strapdown inertial measurement unit and a satellite differential positioning system.

[0176] Strapdown inertial measurement unit, such as Figure 4 As shown, it includes an inertial measurement unit 42, a navigation computer 44, a secondary power supply module 40, a crystal oscillator 48, an external connector 46, and a mobile station satellite receiver 49.

[0177] 1) Inertial Measurement Unit

[0178] The inertial measurement unit 42 mainly acquires the acceleration and angular velocity information of the carrier and uploads the data to the navigation computer 44 through a four-wire SPI interface. The inertial measurement unit 42 has a built-in 3-axis gyroscope and a 3-axis accelerometer, and its specific specifications are shown in Table 1.

[0179]

[0180]

[0181] Table 1

[0182] Hardware circuit design diagram as follows Figure 5 As shown. The chip connects to the navigation computer 44 via a four-wire SPI interface, is powered by a 3.3V power supply, and is equipped with an independent bypass capacitor for filtering.

[0183] 2) Navigation computer

[0184] The navigation computer 44 primarily performs navigation algorithm calculations. In this embodiment, the navigation computer 44's operating frequency is set to 160MHz, equipped with a floating-point computing unit, 2MB of its own program storage space, and 800KB of RAM, which can meet the navigation calculation requirement of 5ms per cycle. Furthermore, the navigation computer 44 also has abundant DMA channels for off-chip operations and logical calculations. Specific resource allocation is shown in Table 2 below.

[0185] 1 USART0 external communication Navigation data output TTL@3.3V 2 USART1 external communication Navigation data output RS-422@3.3V 3 SPI0 external communication Four-wire SPI, speed 25MHz 4 SPI1 Inertial Measurement Unit Four-wire SPI

[0186] Table 2

[0187] Specific hardware design such as Figure 6 As shown. The minimum system of this chip includes: a startup capacitor, a reset circuit, and a clock source, etc.

[0188] 3) Secondary power supply module

[0189] Secondary power supply module 40 Figure 7 As shown, the main focus is on adjusting and matching the internal power supply. In this embodiment, two independent chips are used for power output: one to supply power to the mobile station satellite receiver 49, and the other to other digital circuits on the board. To improve power performance and reduce interference between devices, π-type filters were designed for both the input and output during the power supply design process.

[0190] 4) Crystal oscillator

[0191] In this embodiment, the crystal oscillator 48 has good temperature characteristics and high reliability, with a stability of ≤20ppm.

[0192] 5) External connectors

[0193] In this embodiment, the external connector 46 has surface-mount pins with a spacing of 1.0mm and is gold-plated, which reduces contact resistance while ensuring stability.

[0194] The satellite differential positioning system includes a satellite differential positioning system, a rover satellite navigation system, a rover satellite receiver, a rover satellite receiving antenna, a rover satellite receiving feeder, a base station satellite navigation system, a base station satellite receiver, a base station satellite receiving antenna, a base station satellite receiving feeder, a base station satellite receiving feeder, a base station satellite antenna connector, a secondary power supply module, an interface conversion module, and a data fusion unit.

[0195] 1) Mobile station satellite navigation system

[0196] The specific indicators of the mobile station satellite navigation system are shown in Table 3.

[0197]

[0198]

[0199] Table 3

[0200] Specific hardware design circuits are as follows Figure 8 As shown.

[0201] 2) Base station satellite navigation system

[0202] The base station satellite navigation system has both positioning and attitude measurement functions, and together with a high-precision inertial measurement unit, it can achieve high-precision reference attitude acquisition. The main technical specifications are shown in Table 4 below.

[0203]

[0204] Table 4

[0205] The satellite receiver is used to receive high-precision satellite positioning data, achieving high-precision, airborne-grade positioning accuracy. Combined with a high-precision inertial measurement unit and data fusion unit, effective data fusion is achieved to complete the final initial position and attitude measurement.

[0206] Example 4

[0207] According to an embodiment of this application, a task scheduling system for a combined navigation device is also provided, comprising: a data acquisition module configured to acquire data through multiple inertial measurement units and to perform compensation processing on the acquired data using multi-threading; an alignment module configured to preprocess the compensated data and perform alignment based on the preprocessed data; and a scheduling module configured to perform strapdown task scheduling for the combined navigation device after alignment using a multi-task module.

[0208] Optionally, specific examples in this embodiment can refer to the examples described in Embodiments 1 and 2 above, and will not be repeated here.

[0209] Example 5

[0210] Embodiments of this application also provide a storage medium. This storage medium is configured to store program code for performing the methods described in embodiments 1 and 2 above.

[0211] Optionally, in this embodiment, the storage medium may include, but is not limited to, various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0212] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0213] If the integrated units in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in the aforementioned computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause one or more computer devices (which may be personal computers, servers, or network devices, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0214] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0215] In the several embodiments provided in this application, it should be understood that the disclosed client can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, indirect coupling or communication connection between units or modules, and may be electrical or other forms.

[0216] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0217] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0218] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A task scheduling method for a combined navigation device, characterized in that, include: Data is acquired through multiple inertial measurement units, and multi-threading is used to compensate for the acquired data. The compensated data is preprocessed, and alignment is performed based on the preprocessed data; After alignment, a multi-task module is used to perform strapdown task scheduling for the integrated navigation device; The method further includes, after preprocessing the compensated data: Depending on the setup and alignment type, proceed to either normal alignment or rapid alignment. During the rapid alignment process, if the self-check is abnormal, no binding data is received for 1 second or more, or the number of times the reference information is judged to be invalid is greater than or equal to 50, then "rapid alignment abnormal" is reported; if more than or equal to 1 horizontal correction is made based on the binding and alignment data, then "rapid alignment normal" is reported. During normal alignment, if more than 20 horizontal corrections are made based on the setup and alignment data, "alignment normal" is reported; if the inertial measurement unit malfunctions during this period, or fails to receive setup data for 1 second, or continuously determines that the reference information is invalid for more than 50 times, "alignment abnormal" is reported.

2. The method according to claim 1, characterized in that, Before acquiring data using multiple inertial measurement units, the method further includes initializing at least one of the following: system variables, stored information, message information, stored parameters, user parameters, compensation parameters, and configuration parameters.

3. The method according to claim 1, characterized in that, After alignment, the method further includes calibration, wherein calibration includes: determining that calibration is abnormal if multiple inertial measurement units detect abnormalities, fail to receive binding data within a preset time period, or have a number of consecutive invalid reference information that is greater than or equal to a preset number of invalidities.

4. The method according to claim 1, characterized in that, After employing a multi-tasking module to perform strapdown task scheduling on the integrated navigation device, the method further includes: Based on the preprocessed data, attitude calculation is performed to obtain the pose information of the UAV. The system receives satellite differential correction information transmitted by the ground station at a preset frequency and uses the satellite differential correction information to correct the pose information. The drone is navigated based on the corrected pose information.

5. The method according to claim 4, characterized in that, Using the satellite differential correction information to correct the pose information includes: Based on the satellite differential correction information, a Kalman filter is used to estimate the errors in position, velocity, and attitude. The pose information is corrected based on the estimated error.

6. The method according to claim 5, characterized in that, Using Kalman filters to estimate errors in position, velocity, and attitude includes: The position, velocity, and attitude of the navigation solution from the navigation satellite system are input into the Kalman filter as measurement information, serving as initial estimates. In the prediction phase, the Kalman filter linearizes the initial estimate and determines the error covariance based on the linearized initial estimate. The Kalman gain is determined based on the error covariance, and the error covariance is re-determined based on the Kalman gain; The errors in position, velocity, and attitude calculated by the strapdown are estimated based on the redefined error covariance.

7. A task scheduling system for a combined navigation device, characterized in that, include: The data acquisition module is configured to acquire data through multiple inertial measurement units and to use multi-threading to compensate for the acquired data. The alignment module is configured to preprocess the compensated data and perform alignment based on the preprocessed data; The scheduling module is configured to use a multi-task module to perform strapdown task scheduling for the integrated navigation device after alignment. The alignment module is further configured to enter a normal alignment or rapid alignment process based on the setting and alignment type. During the rapid alignment process, if the self-check is abnormal, no binding data is received for 1 second or more, or the number of times the reference information is judged to be invalid is greater than or equal to 50, then "rapid alignment abnormal" is reported; if more than or equal to 1 horizontal correction is made based on the binding and alignment data, then "rapid alignment normal" is reported. During normal alignment, if more than 20 horizontal corrections are made based on the setup and alignment data, "alignment normal" is reported; if the inertial measurement unit malfunctions during this period, or fails to receive setup data for 1 second, or continuously determines that the reference information is invalid for more than 50 times, "alignment abnormal" is reported.

8. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed, the computer performs the method as claimed in any one of claims 1 to 5.

Images