Vehicle-mounted strapdown integrated navigation method and device, electronic equipment and storage medium

Abstract

Embodiments of the present application provide a vehicle-mounted strapdown integrated navigation method and device, electronic equipment and storage medium, belong to navigation technical field, through obtaining the PVT solution state of navigation receiver, when the PVT solution state is floating point solution and carrier phase difference observation is available, filter estimation is carried out based on carrier phase difference observation to obtain first observation error, when the PVT solution state is pseudorange difference solution or single point solution, and pseudorange observation is available, filter estimation is carried out based on pseudorange observation to obtain second observation error, when the PVT solution state is fixed solution, filter estimation is carried out based on position and velocity observation to obtain third observation error, so that the obtained observation error compensates for strapdown calculation, obtains navigation information, realizes switching different observation to carry out error estimation according to positioning state and observation quality, to carry out navigation, greatly improves the integrated navigation precision under complex scene.

Description

Technical Field

[0001] This invention relates to the field of navigation technology, and more specifically, to a vehicle-mounted strapdown navigation method, device, electronic device, and storage medium. Background Technology

[0002] In the field of autonomous driving positioning, Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) integrated navigation is one of the essential absolute positioning methods. Due to the complex urban road environment, GNSS satellite signals are susceptible to problems such as obstruction and multipath effects.

[0003] Traditional GNSS / INS tightly coupled navigation methods typically employ a pseudorange and pseudorange rate tightly coupled approach, directly using the pseudorange and pseudorange rate observations from raw GNSS observations to construct measurement equations. However, because pseudorange information has significant observational noise and is susceptible to multipath effects, this results in low positioning accuracy and poor navigation accuracy. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a vehicle-mounted strapdown navigation method, device, electronic device and storage medium, which can improve the problems of low positioning accuracy and poor navigation accuracy of traditional GNSS / INS strapdown navigation methods.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0006] In a first aspect, embodiments of the present invention provide a method for vehicle-mounted strapdown integrated navigation, the method comprising:

[0007] Obtain the PVT solution status of the navigation receiver;

[0008] When the PVT solution is a floating-point solution, determine whether the carrier phase differential observation of the current epoch is in an available state;

[0009] If the carrier phase differential observation is available, then a filtering estimation is performed based on the carrier phase differential observation to obtain the first observation error;

[0010] When the PVT solution state is pseudorange difference decomposition or single-point solution, determine whether the pseudorange observation of the current epoch is in an available state.

[0011] If the pseudorange observation is available, then a filtered estimation is performed based on the pseudorange observation to obtain the second observation error;

[0012] When the PVT solution state is a fixed solution, a third observation error is obtained by filtering and estimating the position and velocity observations based on the current epoch.

[0013] Based on the first observation error, the second observation error, or the third observation error, the strapdown calculation is compensated to obtain navigation information.

[0014] Furthermore, the method also includes:

[0015] If the carrier phase differential observation is not available, then the step of determining whether the current pseudorange observation is available is performed.

[0016] Furthermore, the method also includes:

[0017] If both the carrier phase differential observation and the pseudorange observation are unavailable, navigation information is obtained using the dead reckoning algorithm.

[0018] Furthermore, the step of determining whether the carrier phase differential observation of the current epoch is in a usable state includes:

[0019] Obtain the carrier phase differential observations and satellite-to-ground unit vectors for each satellite in the current epoch, as well as the vehicle integrated navigation position vector relative to the previous epoch in the current epoch.

[0020] Calculate the product of the position vector and the satellite-to-ground position unit vector, calculate the first difference between the carrier phase differential observation for each satellite and the product, and calculate the first standard deviation of all the first differences;

[0021] Determine whether the first standard deviation is less than a preset first threshold. If it is, the carrier phase differential observation is in an available state; otherwise, the carrier phase differential observation is not in an available state.

[0022] Furthermore, the step of determining whether the pseudorange observation of the current epoch is in a usable state includes:

[0023] Obtain pseudorange observations for each satellite at the current epoch, as well as the satellite-to-ground distance between the vehicle's combined navigation position and the position of each satellite at the current epoch.

[0024] Calculate the second difference between the pseudorange observation for each satellite and the satellite-to-ground distance, and calculate the second standard deviation of all the second differences;

[0025] Determine whether the second standard deviation is less than a preset second threshold. If so, the pseudorange observation is in an available state.

[0026] Further, the step of performing filtering estimation based on the carrier phase differential observations to obtain the first observation error includes:

[0027] The satellite corresponding to the median of all the first differences is taken as the reference satellite, and the first difference of the reference satellite is taken as the first condition value;

[0028] From all the carrier phase differential observations of all satellites in the current epoch, select the carrier phase differential observations whose difference between the first difference and the first condition value is less than the first deviation threshold as the selected observations;

[0029] Based on all the selected observations, establish the first measurement equation and the first state equation;

[0030] Based on the first measurement equation and the first state equation, the Kalman filter is used to estimate the error, and the first observation error is obtained; wherein, the first observation error includes latitude and longitude position error, velocity error and attitude error.

[0031] Further, the step of performing filtering estimation based on the pseudorange observation to obtain the second observation error includes:

[0032] The satellite corresponding to the median of all the second differences is taken as the reference satellite, and the second difference of the reference satellite is taken as the second condition value;

[0033] From all pseudorange observations of all satellites at the current epoch, select pseudorange observations whose difference between the second difference and the second condition value is less than the second deviation threshold as selected observations;

[0034] Based on all the selected observations, a second measurement equation and a second state equation are established.

[0035] Based on the second measurement equation and the second state equation, the Kalman filter is used to estimate the error, and the second observation error is obtained; wherein, the second observation error includes latitude, longitude and altitude position error, velocity error and attitude error.

[0036] Further, the step of compensating the strapdown calculation based on the first observation error, the second observation error, or the third observation error to obtain navigation information includes:

[0037] Based on the first observation error, the second observation error, or the third observation error, the position, velocity, and heading information obtained from the strapdown calculation are compensated to obtain navigation information.

[0038] Furthermore, the step of obtaining the PVT solution state of the navigation receiver includes:

[0039] The PVT solution status is determined based on the status flag of the navigation receiver's PVT solution.

[0040] Furthermore, the formula for calculating the first difference includes:

[0041]

[0042] in, This represents the first difference of the i-th satellite. Let e ​​represent the carrier phase differential observation of the i-th satellite. i Δb represents the satellite-to-ground position vector from the position coordinates of the i-th satellite to the position coordinates of the navigation receiver, and Δb represents the position vector of the vehicle's integrated navigation position relative to the previous epoch.

[0043] Furthermore, the formula for calculating the second difference includes:

[0044] D ρi =ρ i -P i

[0045] Among them, D ρi ρ represents the second difference of the i-th satellite. i Let P represent the pseudorange observation of the i-th satellite. i This represents the vehicle's combined navigation position and the satellite-to-ground distance of the i-th satellite.

[0046] Secondly, embodiments of the present invention provide an in-vehicle strapdown integrated navigation device, including a status determination module, an error estimation module, and a compensation module;

[0047] The state determination module is used to obtain the PVT solution state of the navigation receiver;

[0048] The error estimation module is used to determine whether the carrier phase differential observation of the current epoch is available when the PVT solution state is a floating-point solution. If the carrier phase differential observation is available, the module performs filtering estimation based on the carrier phase differential observation to obtain the first observation error.

[0049] The error estimation module is also used to determine whether the pseudorange observation of the current epoch is available when the PVT solution state is pseudorange difference decomposition or single-point solution. If the pseudorange observation is available, then filter estimation is performed based on the pseudorange observation to obtain the second observation error.

[0050] The compensation module is used to compensate the strapdown calculation based on the first observation error or the second observation error to obtain navigation information.

[0051] Thirdly, embodiments of the present invention provide an electronic device, including a processor and a memory, wherein the memory stores a computer program executable by the processor, and the processor can execute the computer program to implement the vehicle strapdown combination method as described in the first aspect.

[0052] Fourthly, embodiments of the present invention provide a storage medium storing a computer program thereon, which, when executed by a processor, implements the vehicle strapdown combination method as described in the first aspect.

[0053] The vehicle-mounted strapdown integrated navigation method, device, electronic device, and storage medium provided in this invention obtain the PVT solution state of the navigation receiver. When the PVT solution state is a floating-point solution and the carrier phase differential observation of the current epoch is available, a first observation error is obtained by filtering estimation based on the carrier phase differential observation. When the PVT solution state is a pseudorange differential decomposition or a single-point solution and the pseudorange observation of the current epoch is available, a second observation error is obtained by filtering estimation based on the pseudorange observation. When the PVT dissociation state is a fixed solution, a third observation error is obtained by filtering estimation based on the position and velocity observation of the current epoch. Thus, the strapdown calculation is compensated according to the first, second, or third observation error to obtain navigation information. This enables switching between different observations for error estimation based on the positioning state and observation quality for navigation, thereby greatly improving the integrated navigation accuracy in complex scenarios.

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0055] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 A block diagram of an in-vehicle strapdown navigation system provided in an embodiment of the present invention is shown.

[0057] Figure 2 This is a schematic flowchart of one of the vehicle strapdown integrated navigation methods provided in an embodiment of the present invention.

[0058] Figure 3 The second schematic flowchart of the vehicle strapdown integrated navigation method provided in this embodiment of the invention is shown.

[0059] Figure 4 It shows Figure 2 or Figure 3 A flowchart illustrating some sub-steps of step S13.

[0060] Figure 5 It shows Figure 2 or Figure 3 A flowchart illustrating some sub-steps of step S15.

[0061] Figure 6 It shows Figure 2 or Figure 3 A flowchart illustrating some sub-steps of step S14.

[0062] Figure 7 It shows Figure 2 or Figure 3 A flowchart illustrating some sub-steps of step S16.

[0063] Figure 8 A block diagram of an in-vehicle strapdown navigation device provided in an embodiment of the present invention is shown.

[0064] Figure 9 A block diagram of an electronic device provided in an embodiment of the present invention is shown.

[0065] Reference numerals: 100-Vehicle strapdown navigation system; 110-Navigation receiver; 120-Satellite; 130-Vehicle terminal; 140-Vehicle strapdown navigation device; 150-Status determination module; 160-Error estimation module; 170-Compensation module; 180-Electronic equipment. Detailed Implementation

[0066] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0067] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0068] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0069] In GNSS / INS integrated navigation technology for autonomous driving positioning, optimal estimation methods are typically used to obtain navigation information such as vehicle position, velocity, and attitude for autonomous driving decision-making. Among these, the most commonly used optimal estimation method is Kalman filtering, which constructs a state equation based on the vehicle's motion equations and an observation equation based on GNSS observation information. Because the vehicle's motion state has advantages over airborne, missile-borne, and shipborne scenarios, such as less maneuvering, relatively fixed routes, and low speed and low disturbance, the accuracy of the INS kinematic model has a relatively small impact on the accuracy of the optimal estimation.

[0070] However, the driving environment of vehicles is more complex than other scenarios, satellite signals are easily interfered with, and GNSS observations have a significant impact on estimation accuracy. Traditional loose combination methods cannot effectively utilize satellite information for error correction when the accuracy of GNSS PVT solution information decreases in complex scenarios or when the number of available satellites is less than 4, resulting in low positioning accuracy and affecting navigation accuracy.

[0071] Traditional GNSS / INS tight combination methods typically use a pseudorange-pseudorange-rate tight combination approach, directly constructing measurement equations from the pseudorange and pseudorange-rate observations of raw GNSS observations. However, pseudorange information suffers from significant observation noise and is susceptible to multipath effects, leading to low positioning accuracy and impacting navigation accuracy. Furthermore, with a large number of observations, the computational burden of filtering is substantial.

[0072] Based on the above considerations, embodiments of the present invention provide a vehicle-mounted strapdown integrated navigation method, which addresses the problems of low positioning accuracy and poor navigation accuracy inherent in traditional integrated navigation methods. The following describes this solution.

[0073] The vehicle-mounted strapdown navigation method provided in this embodiment of the invention can be applied to... Figure 1The in-vehicle strapdown integrated navigation system 100 shown includes a navigation receiver 110 and an in-vehicle terminal 130. The navigation receiver 110 can communicate with the in-vehicle terminal 130 via a CAN bus, and the navigation receiver can also communicate with multiple navigation satellites 120.

[0074] Navigation receiver 110 is used to receive, track, transform, and measure GNSS signals about satellite 120 to obtain PVT solutions.

[0075] The GNSS signals include, but are not limited to: position and velocity observations relative to each satellite 120, carrier phase differential observations, and pseudorange observations. PVT calculation refers to the position, velocity, and time calculation of the navigation receiver 110.

[0076] The vehicle-mounted terminal 130 is used to implement the vehicle-mounted strapdown navigation method provided in this embodiment of the invention based on the PVT calculation status.

[0077] The vehicle-mounted strapdown integrated navigation system 100 may also include an inertial sensor, which may be fixedly connected to the navigation receiver 110. The inertial sensor may be connected to the vehicle-mounted terminal 130 via a CAN bus. The vehicle-mounted terminal 130 may perform numerical integration based on the output information of the inertial sensor to obtain the strapdown solution.

[0078] In one possible implementation, refer to Figure 2 This invention provides a method for combining vehicle-mounted strapdown systems, which may include the following steps. In this embodiment, the method is applied to... Figure 1 Let's take the vehicle-mounted terminal 130 as an example.

[0079] S11, Obtain the PVT solution status of the navigation receiver. When the PVT solution status is a fixed solution, execute step S12; when the PVT solution status is a floating-point solution, execute step S13; when the PVT solution status is a pseudorange difference decomposition or a single-point solution, execute step S15.

[0080] It should be noted that PVT solution states are generally divided into fixed solutions, floating-point solutions, pseudo-distance-difference decomposition, and single-point solutions.

[0081] S12, based on the position and velocity observations of the current epoch, a filtered estimate is performed to obtain the third observation error.

[0082] S13, determine whether the carrier phase differential observation for the current epoch is available. If yes, proceed to step S14.

[0083] S14, based on carrier phase differential observations, filter estimation is performed to obtain the first observation error.

[0084] S15, determine whether the pseudorange observation for the current epoch is available. If yes, proceed to step S16.

[0085] S16, based on pseudorange observations, a filtered estimation is performed to obtain the second observation error.

[0086] S17. Based on the first observation error, the second observation error, or the third observation error, the strapdown calculation is compensated to obtain navigation information.

[0087] Strapdown inertial navigation (SINS) refers to the process in which the inertial sensor and navigation receiver are fixed together in a strapdown inertial navigation system. The navigation parameters are obtained by acquiring the output information of the inertial sensor and performing numerical integration on this information. The SINS solution includes parameters such as the attitude, velocity, and position of the navigation receiver.

[0088] The vehicle-mounted terminal 130 acquires the output information of the sensor fixed to the navigation receiver 110 in real time, processes the output information, and obtains the strapdown induction solution. At the same time, the navigation receiver 110 processes the acquired GNSS signal of the current epoch in real time, obtains the PVT solution, and sends it to the vehicle-mounted terminal 130 in real time.

[0089] The vehicle terminal 130 acquires the PVT solution of the navigation receiver 110 in the current epoch and determines the PVT solution status. In one possible implementation, the PVT solution includes a status identifier, with each status identifier corresponding to a PVT solution status. The vehicle terminal 130 can determine the PVT solution status based on the status identifier of the navigation receiver 110's PVT solution.

[0090] When the PVT calculation state is a fixed solution, the vehicle terminal 130 performs filtering estimation based on the position and velocity observations measured by the navigation receiver 110 at the current epoch to obtain a third observation error. When the PVT solution state is a floating-point solution, and the carrier phase differential observations measured by the navigation receiver 110 at the current epoch are available, the vehicle terminal 130 performs filtering estimation based on the carrier phase differential observations to obtain a first observation error. When the PVT solution state is a pseudorange-difference decomposition or a single-point solution, and the pseudorange observations measured by the navigation receiver 110 at the current epoch are available, the vehicle terminal 130 performs filtering estimation based on the pseudorange observations to obtain a second observation error. Furthermore, the vehicle terminal 130 compensates for the strapdown induction converter solution based on the first, second, or third observation errors to obtain navigation information.

[0091] Carrier phase differential information can provide the difference in relative distance between the satellite and the receiver between consecutive time intervals. It has low observation noise, is not easily affected by multipath effects, and has high observation accuracy.

[0092] Compared with traditional integrated navigation methods, the vehicle-mounted strapdown integrated navigation method provided in this embodiment of the invention switches between position and velocity observations, carrier phase differential observations, or pseudorange observations for error estimation based on positioning status and observation quality, and compensates for strapdown calculations based on the estimated observation errors to obtain navigation information. This can minimize the impact of multipath effects and greatly improve positioning accuracy and navigation accuracy in complex scenarios.

[0093] Considering that when the PVT solution is a floating-point solution, the carrier phase differential observation for the current epoch may be unavailable, in order to ensure smooth navigation and maximize navigation accuracy, in one possible implementation, referencing Figure 3 In step S13, if it is determined that the carrier phase differential observation is unavailable, then step S15 is executed. In floating-point solution, if the carrier phase differential observation is unavailable, it is determined whether the pseudorange observation is available. If so, filtering estimation is performed based on the pseudorange observation to compensate for the estimated second observation error in strapdown solution, thereby obtaining navigation information.

[0094] Furthermore, considering that pseudorange observations are unavailable, in order to maximize navigation accuracy and provide timely navigation information, in one possible implementation, please continue to refer to... Figure 3 The vehicle strapdown navigation method provided in this embodiment of the invention may further include step S18, in which step S18 is executed when it is determined in step S15 that the pseudorange observation of the current epoch is unavailable.

[0095] S18 uses dead reckoning to obtain navigation information.

[0096] Dead reckoning is a method that calculates the next position based on the distance and bearing of a vehicle's movement, given the current position. Dead reckoning is a traditional navigation method in the field of navigation technology and will not be described further in this embodiment.

[0097] The method for determining whether the carrier phase differential observation of the current epoch is available can be flexibly set. For example, it can be determined according to preset rules or by using a neural network algorithm. In this embodiment, no specific limitation is made.

[0098] To further improve positioning accuracy and navigation precision, a standard deviation and a first threshold are introduced in the process of determining whether the carrier phase differential observation is available at the current epoch. The first threshold is a value set based on extensive historical experience data or after multiple experiments. Based on this, refer to... Figure 4 The above step S13 can be further implemented as the following steps.

[0099] S131, obtain the carrier phase differential observation and satellite-to-ground position unit vector of each satellite in the current epoch, as well as the position vector of the vehicle integrated navigation position in the current epoch relative to the previous epoch.

[0100] S132, calculate the product of the position vector and the satellite-to-ground position unit vector, calculate the first difference between the carrier phase differential observation and the product for each satellite, and calculate the first standard deviation of all the first differences.

[0101] S133, determine whether the first standard deviation is less than a preset first threshold. If yes, the carrier phase differential observation is in an available state; otherwise, the carrier phase differential observation is not in an available state.

[0102] It should be understood that satellite systems used for navigation consist of multiple satellites, and therefore, for each satellite, there is a carrier phase differential observation and a position vector.

[0103] The formula for calculating the first difference can be expressed as:

[0104] in, This represents the first difference of the i-th satellite. Let e ​​represent the carrier phase differential observation of the i-th satellite. i Δb represents the satellite-to-ground position vector from the position coordinates of the i-th satellite to the position coordinates of the navigation receiver, and Δb represents the position vector of the vehicle's integrated navigation position relative to the previous epoch.

[0105] The first difference among all satellites can be represented by a multidimensional matrix, which can be: Where n represents the number of available carrier phase differential observations.

[0106] The first standard deviation of all first differences can be expressed as: std(N) n×1 The first threshold can be expressed as T. stdcp Based on this, when std(N) is satisfied... n×1 ) <T stdcp When this occurs, the carrier phase differential observation is available.

[0107] Similarly, the method for determining whether the carrier phase differential observation of the current epoch is in a usable state can be flexibly set. For example, it can be determined according to preset rules or by using a neural network algorithm. In this embodiment, no specific limitation is made.

[0108] To further improve positioning accuracy and navigation precision, a standard deviation and a second threshold are introduced in the process of determining whether the pseudorange observations of the current epoch are usable. The second threshold is a value set based on extensive historical experience data or after multiple experiments. Based on this, referencing... Figure 5 The above step S15 can be further implemented as the following steps.

[0109] S151, obtain the pseudorange observations of each satellite at the current epoch, as well as the satellite-to-ground distance between the vehicle's combined navigation position and the position of each satellite at the current epoch.

[0110] S152, calculate the second difference between the pseudorange observation of each satellite and the satellite-to-ground distance, and calculate the second standard deviation of all second differences.

[0111] S153, determine whether the second standard deviation is less than the preset second threshold. If yes, the pseudorange observation is available; otherwise, the pseudorange observation is unavailable.

[0112] Since the satellite system used for navigation includes multiple satellites, for each satellite 120, the navigation receiver can also observe the pseudorange of that satellite, as well as the satellite-to-ground distance between the vehicle's combined navigation position in the previous epoch and that satellite's position.

[0113] The formula for calculating the second difference can be expressed as: D ρi =ρ i -P i .

[0114] Among them, D ρi ρ represents the second difference of the i-th satellite. i Let P represent the pseudorange observation of the i-th satellite. i This represents the vehicle's combined navigation position and the satellite-to-ground distance of the i-th satellite.

[0115] The second difference of all satellites can be represented by a multidimensional matrix, which can be: M m×1 =[ρ1-P1, ρ2-P2,…,ρ m -P m ]. Where m represents the number of available pseudorange observations.

[0116] The second standard deviation of all second differences can be expressed as: std(M m×1 The second threshold can be expressed as T. stdpsr Based on this, when std(M) is satisfied... m×1 ) <T stdpsr When this occurs, the pseudorange observation is available.

[0117] The filtering estimation method can be flexibly selected. For example, it can be a loose combination Kalman filter, a median filter, a first-order filter, etc. In this embodiment, no specific limitation is made.

[0118] In one possible implementation, for step S12, when the PVT solution state is a fixed interpretation, a loosely combined Kalman filter can be applied to the position and velocity observations of the current epoch to obtain the third observation error. Since loosely combined Kalman filtering based on position and velocity observations is a commonly used method in navigation, it will not be described in detail in this implementation.

[0119] In traditional integrated navigation methods, clock bias exists in the navigation receiver for different satellites, leading to poor positioning accuracy. In one possible implementation, to minimize navigation receiver clock bias and improve positioning accuracy when using carrier phase differential observations for filtering estimation, inter-satellite differential and Kalman filtering are introduced. Specifically, refer to... Figure 6 The above step S14 can be further implemented as the following steps.

[0120] S141, take the satellite corresponding to the median of all the first differences as the reference satellite, and take the first difference of the reference satellite as the first condition value.

[0121] S142, from all the carrier phase differential observations of all satellites in the current epoch, select the carrier phase differential observations whose difference between the first difference and the first condition value is less than the first deviation threshold as the selected observations.

[0122] S143, Based on all selected observations, establish the first measurement equation and the first state equation.

[0123] S144. Based on the first measurement equation and the first state equation, the first observation error is obtained by using Kalman filtering to estimate the error.

[0124] It should be noted that the first observation error includes, but is not limited to: latitude and longitude position error, velocity error, and attitude error. The first deviation threshold is a value set based on a large amount of historical experience data or after multiple experiments.

[0125] The multidimensional matrix of the first difference The satellite corresponding to the median (i.e., the reference satellite) is designated ref1. The first difference of the reference satellite is used as the first conditional value for the inter-satellite difference. The first conditional value can be expressed as: The first deviation threshold can be represented as T. maxcp .

[0126] For the carrier phase differential observation of the i-th satellite, the following conditions are met: When the carrier phase differential observation is selected, then the carrier phase differential observation is the selected observation.

[0127] The first state equation can be expressed as:

[0128] In the first state equation, And, X1(t)=[δr, δv, δΨ, δb a ,δb g ,δt ru ] T , It is the first-order differential of X1(t).

[0129] Where δr is the latitude, longitude, and altitude position error in the northeast coordinate system, δv is the velocity error in the northeast coordinate system, δΨ is the attitude error, and δb is the position error. a For the accelerometer zero bias error, δb g For the gyroscope's zero bias error, δt ru Let I be the observation error caused by the difference in clock bias between epochs of the navigation receiver, and let I be a 3×3 identity matrix. For the antisymmetric matrix of Earth's rotation speed, Let be the rotation matrix from the vehicle coordinate system to the navigation coordinate system. Let w(t) be the accelerometer measurement in the carrier coordinate system, and w(t) be the Gaussian white noise vector. The carrier can be a navigation receiver.

[0130] The first measurement equation can be expressed as: Z1(t)=H1(t)X1(t)+v(t).

[0131] In the first measurement equation

[0132] as well as,

[0133] Where v(t) is the Gaussian white noise vector.

[0134] Based on the first state equation and the first measurement equation mentioned above, the first observation error is estimated using Kalman filtering, and the continuous Kalman filtering formula is written as the discrete Kalman filtering calculation formula as follows.

[0135]

[0136] In the above discrete Kalman filter calculation formula, where For t k-1 to t k One-step transition state estimator, Φ k / k-1 =I+F(t) k-1 T, P k / k-1 For t k-1 to tk One-step transition state error matrix, K k Let P be the filter gain matrix. k For t k The state error matrix at time t, Q k-1 Let R be the state noise matrix. k-1 This is the measurement noise matrix.

[0137] Substituting the first measurement equation and the first state equation into the discrete Kalman filter calculation formula, the estimated first observation error can be obtained.

[0138] Through the above steps S141-S144, a reference satellite is used as the inter-satellite differential to eliminate the influence of satellite clock error and receiver clock error on positioning based on the first condition value of the reference satellite, thereby greatly improving positioning accuracy.

[0139] There are various satellite systems used for navigation, such as GPS, Galileo, and BeiDou. Navigation receivers process raw observations from different satellite systems differently, resulting in variations in receiver clock bias characteristics for each system.

[0140] In one possible implementation, to eliminate errors introduced by the navigation receiver's different processing of different satellite systems and to improve positioning accuracy when performing filtering estimation based on pseudorange, inter-satellite differential and Kalman filtering are introduced, and the pseudorange observations are processed by a subsystem. Specifically, refer to... Figure 7 The above step S16 can be further implemented as the following steps.

[0141] S161, take the satellite corresponding to the median of all the second differences as the reference satellite, and take the second difference of the reference satellite as the second condition value.

[0142] S162, from all pseudorange observations of all satellites in the current epoch, select pseudorange observations whose difference between the second difference and the second condition value is less than the second deviation threshold as selected observations.

[0143] S163, based on all selected observations, establish the second measurement equation and the second state equation.

[0144] S164. Based on the second measurement equation and the second state equation, the second observation error is obtained by using Kalman filtering to estimate the error.

[0145] It should be noted that the second observation error can also include latitude, longitude, altitude, velocity, and attitude errors. The second deviation threshold is a value set based on a large amount of historical experience data or after multiple experiments.

[0146] The multidimensional matrix M of the second differencem×1 =[ρ1-P1, ρ2-P2,…,ρ m -P m The satellite corresponding to the median of ] is designated ref2. The second difference of the reference satellite is used as the second conditional value for the inter-satellite difference. The second conditional value can be expressed as: ρ ref2 -P ref2 The second deviation threshold can be expressed as T. maxpsr .

[0147] For the pseudorange observation of the i-th satellite, the following condition is satisfied (ρ i -P i )-(ρ ref -P ref )< maxpsr When the pseudorange observation is selected, then the pseudorange observation is the selected observation.

[0148] The second state equation can be expressed as:

[0149] In the second state equation, X2(t) = [δr, δv, vΨ, δb] a ,δb g ,δt gu ,δt cu ] T Among them, δt gu This refers to the observational error caused by the clock bias of the navigation receiver in the GPS system. δt cu This refers to the observation error caused by the clock bias of the navigation receiver in the BeiDou system. It should be understood that when the number of satellite systems changes, the observation error caused by the navigation receiver clock bias can be adjusted in X2(t), for example, by adding, deleting, or modifying it.

[0150] The second measurement equation can be expressed as: Z2(t)=H2(t)X2(t)+v(t).

[0151] In the second measurement equation

[0152] as well as,

[0153] in, e represents the estimated distance between the nth satellite and the Earth in the GPS system. gn This represents the unit vector representing the satellite position of the nth satellite in the GPS system. e represents the estimated distance between the nth Beidou satellite and its Earth. cn This represents the unit vector indicating the satellite's ground position of the nth Beidou satellite.

[0154] Similarly, by substituting the second measurement equation and the second state equation into the discrete Kalman filter calculation formula, the estimated second observation error can be obtained.

[0155] Through the above steps S161-S164, a reference satellite is used as the inter-satellite difference. Based on the second condition value of the reference satellite, the influence of satellite clock error and receiver clock error on positioning is eliminated. At the same time, the receiver error of the navigation receiver for different satellite systems is estimated separately, and the observation noise of different satellite systems is set separately, which can greatly improve the positioning accuracy.

[0156] After obtaining the estimated first, second, or third observation error, the on-board terminal compensates for the position, speed, and heading information obtained from the strapdown calculation based on the first, second, or third observation error to obtain navigation information.

[0157] Strapdown induction generator (SIT) solutions include attitude update methods, velocity update methods, and position update methods.

[0158] The pose update method can be represented as:

[0159] Solving the above differential equation updates the current attitude matrix, where... This represents the angular velocity of the carrier system relative to the navigation system. The pitch, roll, and yaw angles of the carrier can be further calculated using the attitude matrix.

[0160] The speed update method can be expressed as: in, The specific force measured by the accelerometer under the load system, g n This is the local gravitational acceleration.

[0161] The location update method can be represented as:

[0162]

[0163] Where L is latitude, R M R is the radius of the meridian circle. N denoted as the radius of the circle, and h as the altitude.

[0164] When the first, second, or third observation error is obtained, each error is compensated for by adding, multiplying, or any other compensation method, and then applied to the navigation parameters such as attitude, position, and velocity obtained by strapdown calculation. This completes the compensation and yields the navigation information.

[0165] The vehicle-mounted strapdown integrated navigation method provided in this invention achieves seamless switching between loose velocity-position combination, tight carrier phase differential combination, and tight pseudorange combination based on satellite positioning status and the quality of raw observation information, thereby improving the integrated navigation accuracy in complex scenarios. The measurement model for carrier phase differential is simplified, and inter-satellite differential is performed using the median method to select a reference satellite, further eliminating navigation receiver clock bias and improving navigation accuracy. Simultaneously, the receiver clock bias estimation method of the sub-satellite system is used in the second measurement equation and the second state equation of the pseudorange observation to achieve more accurate correction of the raw pseudorange observation, further improving navigation accuracy.

[0166] Based on the inventive concept of the above-described vehicle strapdown navigation method, in one possible implementation, the present invention also provides a vehicle strapdown navigation device 140, which can be applied to... Figure 1 The vehicle-mounted terminal 130 is shown in the image. (Refer to...) Figure 8 The vehicle-mounted strapdown navigation system 140 may include a status determination module 150, an error estimation module 160, and a compensation module 170.

[0167] The state determination module 150 is used to obtain the PVT solution state of the navigation receiver.

[0168] The error estimation module 160 is used to determine whether the carrier phase differential observation of the current epoch is available when the PVT solution is a floating-point solution. If the carrier phase differential observation is available, the first observation error is obtained by filtering estimation based on the carrier phase differential observation.

[0169] The error estimation module 160 is also used to determine whether the pseudorange observation of the current epoch is available when the PVT solution state is pseudorange difference decomposition or single-point solution. If the pseudorange observation is available, the second observation error is obtained by filtering estimation based on the pseudorange observation.

[0170] The error estimation module 160 is also used to perform filtering estimation based on the position and velocity observations of the current epoch when the PVT solution state is a fixed solution, to obtain the third observation error.

[0171] The compensation module 170 is used to compensate the strapdown solution based on the first observation error, the second observation error, or the third observation error to obtain navigation information.

[0172] In the aforementioned vehicle-mounted strapdown integrated navigation device 140, through the coordinated action of the state determination module 150, the error estimation module 160, and the compensation module 170, the device switches between position and velocity observations, carrier phase differential observations, or pseudorange observations to estimate errors based on the positioning status and observation quality. Based on the estimated observation errors, the device compensates for the strapdown solution to obtain navigation information. This can minimize the impact of multipath effects and greatly improve the positioning accuracy and navigation accuracy in complex scenarios.

[0173] Specific limitations regarding the in-vehicle strapdown navigation device 140 can be found in the limitations of the in-vehicle strapdown navigation method described above, and will not be repeated here. Each module in the aforementioned in-vehicle strapdown navigation device 140 can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in the electronic device, or stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0174] In one embodiment, an electronic device 180 is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 9 As shown, the electronic device 180 includes a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor of the electronic device 180 provides computing and control capabilities. The memory of the electronic device 180 includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface of the electronic device 180 is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, near-field communication (NFC), or other technologies. When the computer program is executed by the processor, it implements the in-vehicle strapdown navigation method provided in the above embodiment.

[0175] Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the electronic device 180 to which the present invention is applied. The specific electronic device 180 may include, but is not limited to, the following: Figure 9 The diagram shows more or fewer components, or combinations of certain components, or different component arrangements.

[0176] In one embodiment, the in-vehicle strapdown navigation device 140 provided by the present invention can be implemented as a computer program, which can be implemented in, for example... Figure 9The electronic device 180 shown operates on this device. The memory of the electronic device 180 can store various program modules that make up the in-vehicle strapdown navigation system 140, for example, Figure 8 The diagram shows a state determination module 150, an error estimation module 160, and a compensation module 170. The computer program comprised of these modules causes the processor to execute the steps of the in-vehicle strapdown integrated navigation method described in this specification.

[0177] For example, Figure 9 The electronic device 180 shown can be accessed via, for example Figure 8 The status determination module 150 in the vehicle-mounted strapdown navigation device 140 shown executes step S11. The electronic device 180 can execute steps S12-S16 through the error estimation module 160. The electronic device 180 can execute step S17 through the compensation module 170.

[0178] In one embodiment, an electronic device 180 is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to perform the following steps: acquiring the PVT solution state of the navigation receiver; when the PVT solution state is a floating-point solution, determining whether the carrier phase differential observation of the current epoch is in an available state; if the carrier phase differential observation is in an available state, performing filtering estimation based on the carrier phase differential observation to obtain a first observation error; when the PVT solution state is a pseudorange differential decomposition or a single-point solution, determining whether the pseudorange observation of the current epoch is in an available state; if the pseudorange observation is in an available state, performing filtering estimation based on the pseudorange observation to obtain a second observation error; when the PVT solution state is a fixed solution, performing filtering estimation based on the position and velocity observation of the current epoch to obtain a third observation error; and compensating the strapdown induction converter solution according to the first observation error, the second observation error, or the third observation error to obtain navigation information.

[0179] In one embodiment, a storage medium is provided storing a computer program. When the computer program is executed by a processor, it performs the following steps: acquiring the PVT solution state of the navigation receiver; when the PVT solution state is a floating-point solution, determining whether the carrier phase differential observation of the current epoch is available; if the carrier phase differential observation is available, performing filtering estimation based on the carrier phase differential observation to obtain a first observation error; when the PVT solution state is a pseudorange differential decomposition or a single-point solution, determining whether the pseudorange observation of the current epoch is available; if the pseudorange observation is available, performing filtering estimation based on the pseudorange observation to obtain a second observation error; when the PVT solution state is a fixed solution, performing filtering estimation based on the position and velocity observation of the current epoch to obtain a third observation error; and compensating the strapdown induction solution according to the first observation error, the second observation error, or the third observation error to obtain navigation information.

[0180] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0181] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0182] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion 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 a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0183] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A vehicle-mounted strapdown integrated navigation method, characterized in that, The method includes: Obtain the PVT solution status of the navigation receiver; When the PVT solution is a floating-point solution, determine whether the carrier phase differential observation of the current epoch is in an available state; If the carrier phase differential observation is available, then a filtering estimation is performed based on the carrier phase differential observation to obtain the first observation error; When the PVT solution state is pseudorange difference decomposition or single-point solution, determine whether the pseudorange observation of the current epoch is in an available state. If the pseudorange observation is available, then a filtered estimation is performed based on the pseudorange observation to obtain the second observation error; When the PVT solution state is a fixed solution, a third observation error is obtained by filtering and estimating the position and velocity observations based on the current epoch. Based on the first observation error, the second observation error, or the third observation error, the strapdown calculation is compensated to obtain navigation information.

2. The vehicle-mounted strapdown integrated navigation method according to claim 1, characterized in that, The method further includes: If the carrier phase differential observation is not available, then the step of determining whether the pseudorange observation of the current epoch is available is performed.

3. The vehicle-mounted strapdown integrated navigation method according to claim 2, characterized in that, The method further includes: If the pseudorange observation is unavailable, navigation information is obtained using the dead reckoning algorithm.

4. The vehicle-mounted strapdown integrated navigation method according to any one of claims 1 to 3, characterized in that, The step of determining whether the carrier phase differential observation of the current epoch is in a usable state includes: Obtain the carrier phase differential observations and satellite-to-ground unit vectors for each satellite in the current epoch, as well as the vehicle integrated navigation position vector relative to the previous epoch in the current epoch. Calculate the product of the position vector and the satellite-to-ground position unit vector, calculate the first difference between the carrier phase differential observation for each satellite and the product, and calculate the first standard deviation of all the first differences; Determine whether the first standard deviation is less than a preset first threshold. If it is, the carrier phase differential observation is in an available state; otherwise, the carrier phase differential observation is not in an available state.

5. The vehicle-mounted strapdown integrated navigation method according to any one of claims 1 to 3, characterized in that, The step of determining whether the pseudorange observation of the current epoch is available includes: Obtain pseudorange observations for each satellite at the current epoch, as well as the satellite-to-ground distance between the vehicle's combined navigation position and the position of each satellite at the current epoch. Calculate the second difference between the pseudorange observation for each satellite and the satellite-to-ground distance, and calculate the second standard deviation of all the second differences; Determine whether the second standard deviation is less than a preset second threshold. If so, the pseudorange observation is in an available state.

6. The vehicle-mounted strapdown integrated navigation method according to claim 4, characterized in that, The step of performing filtering estimation based on the carrier phase differential observation to obtain the first observation error includes: The satellite corresponding to the median of all the first differences is taken as the reference satellite, and the first difference of the reference satellite is taken as the first condition value; From all the carrier phase differential observations of all satellites in the current epoch, select the carrier phase differential observations whose difference between the first difference and the first condition value is less than the first deviation threshold as the selected observations; Based on all the selected observations, establish the first measurement equation and the first state equation; Based on the first measurement equation and the first state equation, the Kalman filter is used to estimate the error, and the first observation error is obtained; wherein, the first observation error includes latitude and longitude position error, velocity error and attitude error.

7. The vehicle-mounted strapdown integrated navigation method according to claim 5, characterized in that, The step of performing filtering estimation based on the pseudorange observation to obtain the second observation error includes: The satellite corresponding to the median of all the second differences is taken as the reference satellite, and the second difference of the reference satellite is taken as the second condition value; From all pseudorange observations of all satellites at the current epoch, select pseudorange observations whose difference between the second difference and the second condition value is less than the second deviation threshold as selected observations; Based on all the selected observations, a second measurement equation and a second state equation are established. Based on the second measurement equation and the second state equation, the Kalman filter is used to estimate the error, and the second observation error is obtained; wherein, the second observation error includes latitude, longitude and altitude position error, velocity error and attitude error.

8. The vehicle-mounted strapdown integrated navigation method according to any one of claims 1 to 3, characterized in that, The step of compensating the strapdown calculation based on the first observation error, the second observation error, or the third observation error to obtain navigation information includes: Based on the first observation error, the second observation error, or the third observation error, the position, velocity, and heading information obtained from the strapdown calculation are compensated to obtain navigation information.

9. The vehicle-mounted strapdown integrated navigation method according to any one of claims 1 to 3, characterized in that, The step of obtaining the PVT solution state of the navigation receiver includes: The PVT solution status is determined based on the status flag of the navigation receiver's PVT solution.

10. The vehicle-mounted strapdown integrated navigation method according to claim 4, characterized in that, The formula for calculating the first difference includes: in, This represents the first difference of the i-th satellite. This represents the carrier phase differential observation of the i-th satellite. This represents the satellite-to-ground position vector representing the distance from the position coordinates of the i-th satellite to the position coordinates of the navigation receiver. This represents the position vector of the vehicle's combined navigation position relative to the previous epoch.

11. The vehicle-mounted strapdown integrated navigation method according to claim 5, characterized in that, The formula for calculating the second difference includes: in, This represents the second difference of the i-th satellite. This represents the pseudorange observation of the i-th satellite. This represents the vehicle's combined navigation position and the satellite-to-ground distance of the i-th satellite.

12. A vehicle-mounted strapdown navigation system, characterized in that, It includes a state determination module, an error estimation module, and a compensation module; The state determination module is used to obtain the PVT solution state of the navigation receiver; The error estimation module is used to determine whether the carrier phase differential observation of the current epoch is available when the PVT solution state is a floating-point solution. If the carrier phase differential observation is available, the module performs filtering estimation based on the carrier phase differential observation to obtain the first observation error. The error estimation module is also used to determine whether the pseudorange observation of the current epoch is available when the PVT solution state is pseudorange difference decomposition or single-point solution. If the pseudorange observation is available, then filter estimation is performed based on the pseudorange observation to obtain the second observation error. The error estimation module is also used to perform filtering estimation based on the position and velocity observations of the current epoch when the PVT solution state is a fixed solution, to obtain the third observation error; The compensation module is used to compensate the strapdown calculation based on the first observation error, the second observation error, or the third observation error to obtain navigation information.

13. An electronic device, characterized in that, It includes a processor and a memory, the memory storing a computer program executable by the processor, the processor being able to execute the computer program to implement the vehicle strapdown integrated navigation method as described in any one of claims 1 to 11.

14. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the vehicle strapdown navigation method as described in any one of claims 1 to 11.

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