WO2024149391A1

WO2024149391A1 - In-vehicle strapdown integrated navigation method and apparatus, and electronic device and storage medium

Info

Publication number: WO2024149391A1
Application number: PCT/CN2024/072135
Authority: WO
Inventors: 徐浩
Original assignee: 广州导远电子科技有限公司
Priority date: 2023-01-13
Filing date: 2024-01-12
Publication date: 2024-07-18
Also published as: CN116182847A

Abstract

An in-vehicle strapdown integrated navigation method and apparatus, and an electronic device and a storage medium, which belong to the technical field of navigation. The method comprises: acquiring a PVT solving state of a navigation receiver; when the PVT solving state is a float solution and a carrier phase differential observation quantity is available, performing filtering estimation on the basis of the carrier phase differential observation quantity to obtain a first observation error; when the PVT solving state is a pseudo-range differential solution or a single-point solution, and a pseudo-range observation quantity is available, performing filtering estimation on the basis of the pseudo-range observation quantity to obtain a second observation error; when the PVT solving state is a fixed solution, performing filtering estimation on the basis of position and velocity observation quantities to obtain a third observation error; and compensating for strapdown calculation according to the obtained observation error, so as to obtain navigation information.

Description

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

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure claims the priority of the Chinese patent application with application number CN202310093543.1 and title “Vehicle-mounted strapdown combined navigation method, device, electronic device and storage medium” filed with the Chinese Patent Office on January 13, 2023, the entire contents of which are incorporated by reference in this disclosure.

Technical Field

The present disclosure relates to the field of navigation technology, and in particular to a vehicle-mounted strapdown combined navigation method, device, electronic equipment and storage medium.

Background technique

In the field of autonomous driving positioning, the combined navigation of the Global Navigation Satellite System (GNSS) and the Inertial Navigation System (INS) is one of the necessary absolute positioning methods. Due to the complex urban road environment, GNSS satellite signals are easily affected by problems such as occlusion and multipath effects.

In the traditional GNSS/INS tightly integrated navigation method, the tight combination of pseudorange and pseudorange rate is usually adopted, and the pseudorange and pseudorange rate observations of the original GNSS observations are directly used to construct the measurement equation. Since the pseudorange information observation noise is large and is easily affected by the multipath effect, it leads to low positioning accuracy and poor navigation accuracy.

Summary of the invention

In view of this, the purpose of the present disclosure is to provide a vehicle-mounted strapdown integrated navigation method, device, electronic device and storage medium, which can improve the problems of low positioning accuracy and poor navigation accuracy existing in the traditional GNSS/INS tightly integrated navigation method.

In order to achieve the above objectives, the technical solutions adopted by the embodiments of the present disclosure are as follows:

In a first aspect, an embodiment of the present disclosure provides a vehicle-mounted strapdown integrated navigation method, the method comprising:

Get the PVT solution status of the navigation receiver;

When the PVT solution state is a floating point solution, determining whether the carrier phase differential observation quantity of the current epoch is in an available state;

If the carrier phase differential observation amount is in an available state, filtering estimation is performed based on the carrier phase differential observation amount to obtain a first observation error;

When the PVT solution state is pseudorange difference decomposition or single point solution, determining whether the pseudorange observation quantity of the current epoch is in an available state;

If the pseudorange observation value is in an available state, filtering estimation is performed based on the pseudorange observation value to obtain a second observation error;

When the PVT solution state is a fixed solution, filtering estimation is performed based on the position and velocity observations of the current epoch to obtain a third observation error;

The strapdown solution is compensated according to the first observation error, the second observation error or the third observation error to obtain navigation information.

Optionally, the method further includes:

If the carrier phase differential observation is not in an available state, the step of determining whether the current pseudorange observation is in an available state is performed.

Optionally, the method further includes:

If both the carrier phase difference observation and the pseudorange observation are in an unavailable state, the navigation information is obtained by using the dead reckoning algorithm.

Optionally, the step of determining whether the carrier phase differential observation quantity of the current epoch is in an available state includes:

Obtain the carrier phase difference observation and satellite-earth 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;

Calculating the product of the position vector and the satellite-earth position unit vector, calculating a first difference between the carrier phase differential observation of each satellite and the product, and calculating a first standard deviation of all the first differences;

It is determined whether the first standard deviation is less than a preset first threshold value. If so, the carrier phase differential observation amount is in an available state; otherwise, the carrier phase differential observation amount is not in an available state.

Optionally, the step of determining whether the pseudorange observation quantity of the current epoch is in an available state includes:

Obtain the pseudorange observation of each satellite in the current epoch, as well as the satellite-earth distance between the vehicle integrated navigation position in the current epoch and the position of each satellite;

Calculating a second difference between the pseudorange observation value of each satellite and the satellite-earth distance, and calculating a second standard deviation of all the second differences;

It is determined whether the second standard deviation is less than a preset second threshold value. If so, the pseudorange observation value is in an available state.

Optionally, the step of performing filtering estimation based on the carrier phase differential observation to obtain a first observation error includes:

Using the satellite corresponding to the median of all the first differences as a reference star, and using the first difference of the reference star as a first condition value;

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

Based on all the selected observation quantities, establishing a first measurement equation and a first state equation;

Based on the first measurement equation and the first state equation, a Kalman filter estimation error is used to obtain a first observation error; wherein the first observation error includes a longitude and latitude position error, a speed error, and an attitude error.

Optionally, the step of performing filtering estimation based on the pseudorange observation to obtain a second observation error includes:

The satellite corresponding to the median of all the second difference values is used as a reference satellite, and the second difference value of the reference satellite is used as a second condition value;

From the pseudorange observations of all satellites in the current epoch, select as the selected observation, a pseudorange observation whose difference between the second difference and the second condition value is less than a second deviation threshold;

Based on all the selected observation quantities, establishing a second measurement equation and a second state equation;

Based on the second measurement equation and the second state equation, Kalman filter estimation error estimation is adopted to obtain a second observation error; wherein the second observation error includes longitude and latitude position error, velocity error and attitude error.

Optionally, the step of compensating the strapdown solution according to the first observation error, the second observation error or the third observation error to obtain navigation information includes:

The position, speed and heading information obtained by strapdown solution are compensated according to the first observation error, the second observation error or the third observation error to obtain navigation information.

Optionally, the step of obtaining the PVT solution state of the navigation receiver includes:

The PVT solution state is determined according to the state flag of the PVT solution of the navigation receiver.

Optionally, the calculation formula of the first difference includes:

in, represents the first difference of the i-th satellite, represents the carrier phase differential observation of the ith satellite, e _i represents the satellite-to-earth position unit vector from the position coordinates of the ith 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.

Optionally, the calculation formula for the second difference includes:
D _ρi ＝ρi-Pi

Wherein, D _ρi represents the second difference of the i-th satellite, _ρi represents the pseudo-range observation of the i-th satellite, and _Pi represents the satellite-earth distance between the vehicle's integrated navigation position and the i-th satellite.

In a second aspect, an embodiment of the present disclosure provides a vehicle-mounted strapdown integrated navigation device, including 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 amount of the current epoch is in an available state when the PVT solution state is a floating point solution, and if the carrier phase differential observation amount is in an available state, perform filtering estimation based on the carrier phase differential observation amount to obtain a first observation error;

The error estimation module is further configured to, when the PVT solution state is pseudorange difference decomposition or single point solution, determine whether the pseudorange observation amount of the current epoch is in an available state, and if the pseudorange observation amount is in an available state, perform filtering estimation based on the pseudorange observation amount to obtain a second observation error;

The compensation module is used to compensate the strapdown solution according to the first observation error or the second observation error to obtain navigation information.

In a third aspect, an embodiment of the present disclosure provides an electronic device, including a processor and a memory, wherein the memory stores a computer program that can be executed by the processor, and the processor can execute the computer program to implement the vehicle-mounted strapdown combination method as described in the first aspect.

In a fourth aspect, an embodiment of the present disclosure provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the vehicle-mounted strapdown combination method as described in the first aspect.

The vehicle-mounted strapdown combined navigation method, device, electronic device and storage medium provided by the embodiments of the present disclosure 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 amount of the current epoch is in an available state, filtering estimation is performed based on the carrier phase differential observation amount to obtain a first observation error. When the PVT solution state is a pseudorange differential solution or a single-point solution and the pseudorange observation amount of the current epoch is in an available state, filtering estimation is performed based on the pseudorange observation amount to obtain a second observation error. When the PVT solution state is a fixed solution, filtering estimation is performed based on the position and velocity observation amount of the current epoch to obtain a third observation error. The strapdown calculation is compensated according to the first observation error, the second observation error or the third observation error to obtain navigation information, and different observation amounts are switched according to the positioning state and the quality of the observation amount to perform error estimation for navigation, thereby greatly improving the precision of combined navigation in complex scenarios.

In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

FIG1 shows a block diagram of a vehicle-mounted strapdown integrated navigation system provided by an embodiment of the present disclosure.

FIG. 2 shows one of the flowcharts of the vehicle-mounted strapdown integrated navigation method provided in an embodiment of the present disclosure.

FIG. 3 shows a second flow chart of the vehicle-mounted strapdown integrated navigation method provided in an embodiment of the present disclosure.

FIG. 4 is a schematic flow chart showing some sub-steps of step S13 in FIG. 2 or FIG. 3 .

FIG. 5 is a schematic flow chart showing some sub-steps of step S15 in FIG. 2 or FIG. 3 .

FIG. 6 is a schematic flow chart showing some sub-steps of step S14 in FIG. 2 or FIG. 3 .

FIG. 7 is a schematic flow chart showing some sub-steps of step S16 in FIG. 2 or FIG. 3 .

FIG8 shows a block diagram of a vehicle-mounted strapdown integrated navigation device provided by an embodiment of the present disclosure.

FIG. 9 shows a block diagram of an electronic device provided by an embodiment of the present disclosure.

Figure numerals: 100 - vehicle-mounted strapdown integrated navigation system; 110 - navigation receiver; 120 - satellite; 130 - vehicle-mounted terminal; 140 - vehicle-mounted strapdown integrated navigation device; 150 - state determination module; 160 - error estimation module; 170 - compensation module; 180 - electronic equipment.

Detailed ways

The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. The components of the embodiments of the present disclosure described and shown in the drawings here can be arranged and designed in various different configurations.

Therefore, the following detailed description of the embodiments of the present disclosure provided in the accompanying drawings is not intended to limit the scope of the present disclosure claimed for protection, but merely represents selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of the present disclosure.

It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

In the GNSS/INS combined navigation technology in the field of autonomous driving positioning, the optimal estimation method is usually used to obtain the vehicle's position, speed, attitude and other navigation information for autonomous driving decision-making. Among them, the most commonly used optimal estimation method is Kalman filtering, which constructs the state equation based on the vehicle's motion equation and the observation equation based on the GNSS observation information. Compared with airborne, missile-borne and ship-borne scenarios, the vehicle's motion state has the advantages of less maneuverability, relatively fixed route, low speed and low disturbance. Therefore, the accuracy of the INS kinematic model has relatively little effect on the accuracy of the optimal estimate.

However, the driving environment of vehicles is more complex than other scenarios, satellite signals are susceptible to interference, and GNSS observations have a greater impact on estimation accuracy. The traditional loose combination method cannot effectively use satellite information for error correction when the accuracy of GNSS PVT solution information decreases in complex scenarios and when the number of available satellites is less than 4, resulting in low positioning accuracy and affecting navigation accuracy.

In the traditional GNSS/INS tight combination method, the pseudorange and pseudorange rate tight combination method is usually used to directly use the pseudorange and pseudorange rate observations of the original GNSS observations to construct the measurement equation. However, the pseudorange information observation noise is large and is easily affected by the multipath effect, resulting in low positioning accuracy and affecting navigation accuracy. At the same time, when there are many observations, the filter operation is large.

Based on the above considerations, the embodiment of the present disclosure provides a vehicle-mounted strapdown integrated navigation method, which can solve the problems of low positioning precision and poor navigation accuracy existing in the traditional integrated navigation method. The solution is introduced below.

The vehicle-mounted strapdown integrated navigation method provided by the embodiment of the present disclosure can be applied to the vehicle-mounted strapdown integrated navigation system 100 shown in Figure 1. The vehicle-mounted strapdown integrated navigation system 100 includes a navigation receiver 110 and a vehicle-mounted terminal 130. The navigation receiver 110 can be connected to the vehicle-mounted terminal 130 through a CAN bus, and the navigation receiver can communicate with multiple navigation satellites 120.

The navigation receiver 110 is used to receive, track, transform and measure GNSS signals related to the satellite 120 to obtain PVT solutions.

The GNSS signals include but are not limited to: position and velocity observations, carrier phase difference observations and pseudo-range observations relative to each satellite 120. PVT solution refers to the position, velocity and time solution of the navigation receiver 110.

The vehicle terminal 130 is used to implement the vehicle strapdown integrated navigation method provided by the embodiment of the present disclosure according to the PVT solution state.

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

In a possible implementation, referring to Fig. 2 , the embodiment of the present disclosure provides a vehicle-mounted strapdown assembly method, which may include the following steps. In this implementation, the method is applied to the vehicle-mounted terminal 130 in Fig. 1 as an example.

S11, obtaining the PVT solution state of the navigation receiver. When the PVT solution state is a fixed solution, execute step S12, when the PVT solution state is a floating point solution, execute step S13, when the PVT solution state is a pseudo-range difference decomposition or a single point solution, execute step S15.

It should be noted that the PVT solution status is generally divided into fixed solution, floating point solution, pseudo-range difference solution and single point solution.

S12, performing filtering estimation based on the position and velocity observations of the current epoch to obtain a third observation error.

S13, determine whether the carrier phase differential observation quantity of the current epoch is in an available state. If so, execute step S14.

S14, performing filtering estimation based on the carrier phase differential observation to obtain a first observation error.

S15, determine whether the pseudo-range observation of the current epoch is in an available state. If yes, execute step S16.

S16, performing filtering estimation based on the pseudorange observation amount to obtain a second observation error.

S17, compensating the strapdown solution according to the first observation error, the second observation error or the third observation error to obtain navigation information.

The strapdown solution refers to the process of obtaining the output information of the inertial sensor and performing numerical integration to obtain the navigation parameters in the strapdown inertial navigation system, which is a fixed connection between the inertial sensor and the navigation receiver. The strapdown solution includes parameters such as the attitude, velocity and position of the navigation receiver.

The vehicle terminal 130 acquires the output information of the relationship sensor connected to the navigation receiver 110 in real time, and processes the output information to obtain the strapdown solution. At the same time, the navigation receiver 110 processes the acquired GNSS signal of the current epoch in real time to obtain the PVT solution and sends it to the vehicle terminal 130 in real time.

The vehicle terminal 130 obtains the PVT solution of the current epoch of the navigation receiver 110 and determines the PVT solution state. In a possible implementation, the PVT solution includes a state identifier, each state identifier corresponds to a PVT solution state, and the vehicle terminal 130 can determine the PVT solution state according to the state identifier of the PVT solution of the navigation receiver 110.

When the PVT calculation state is a fixed solution, the vehicle terminal 130 performs filtering estimation based on the position velocity observation of the current epoch measured by the navigation receiver 110 to obtain the third observation error. When the PVT solution state is a floating point solution, and the carrier phase differential observation of the current epoch measured by the navigation receiver 110 is in an available state, the vehicle terminal 130 performs filtering estimation based on the carrier phase differential observation to obtain the first observation error. When the PVT solution state is a pseudorange difference decomposition or a single point solution, and the pseudorange observation of the current epoch measured by the navigation receiver 110 is in an available state, the vehicle terminal 130 performs filtering estimation based on the pseudorange observation to obtain the second observation error. Furthermore, the vehicle terminal 130 compensates the strapdown solution according to the first observation error, the second observation error or the third observation error to obtain navigation information.

The carrier phase differential information can provide the difference in relative distance between the satellite 120 and the receiver between the previous and next time elements. The observed quantity has low noise, is not easily affected by the multipath effect, and has high observation accuracy.

Compared with the traditional combined navigation method, the vehicle-mounted strapdown combined navigation method provided by the embodiment of the present disclosure switches the position velocity observation, carrier phase differential observation or pseudorange observation for error estimation according to the positioning state and the quality of the observation, and compensates the strapdown solution based on the estimated observation error to obtain navigation information, which can reduce the influence of the multipath effect as much as possible and greatly improve the positioning accuracy and navigation accuracy in complex scenarios.

Considering that when the PVT solution state is a floating point solution, the carrier phase differential observation of the current epoch is unavailable, in order to smoothly carry out navigation and improve navigation accuracy as much as possible, in a possible implementation, referring to FIG. 3, in step S13, if it is determined that the carrier phase differential observation is in an unavailable state, step S15 is executed. In the floating point solution, and when the carrier phase differential observation is unavailable, it is determined whether the pseudorange observation is in an available state. If so, a filtering estimation is performed based on the pseudorange observation to use the estimated second observation error to compensate for the strapdown solution to obtain navigation information.

Optionally, considering that the pseudorange observation amount is in an unavailable state, in order to improve the navigation accuracy as much as possible and provide navigation information in a timely manner, in a possible implementation, please continue to refer to Figure 3, the vehicle-mounted strapdown combined navigation method provided in the embodiment of the present disclosure may also include step S18. When it is determined in step S15 that the pseudorange observation amount of the current epoch is in an unavailable state, step S18 is executed.

S18, obtaining navigation information using a dead reckoning algorithm.

The dead reckoning method is a method of calculating the next moment's position based on the distance and direction of the vehicle's movement under the condition of knowing the current moment's position. The dead reckoning method is a traditional navigation method in the field of navigation technology and will not be introduced in this embodiment.

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

In order to further improve the positioning accuracy and navigation accuracy, the standard deviation and the first threshold are introduced in the process of judging whether the carrier phase differential observation quantity of the current epoch is in an available state. Among them, the first threshold is a value set according to a large amount of historical experience data or after multiple experiments. On this basis, referring to Figure 4, the above step S13 can be further implemented as the following steps.

S131, obtaining the carrier phase difference observation and satellite-earth position unit vector of each satellite in the current epoch, and the position vector of the vehicle integrated navigation position in the current epoch relative to the previous epoch.

S132, calculating the product of the position vector and the satellite-Earth position unit vector, calculating the first difference between the carrier phase differential observation quantity of each satellite and the product, and calculating the first standard deviation of all the first differences.

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

It should be understood that a satellite system used for navigation includes multiple satellites, and therefore, for each satellite, there is a carrier phase difference observation and a position vector.

The calculation formula of the first difference can be expressed as:

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

The first standard deviation of all first differences can be expressed as: std(N _n×1 ), and the first threshold can be expressed as T _stdcp . On this basis, when std(N _n×1 )<T _stdcp is satisfied, the carrier phase difference observation quantity is in an available state.

Similarly, the method for determining whether the carrier phase differential observation quantity of the current epoch is in an available 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.

In order to further improve the positioning accuracy and navigation accuracy, the standard deviation and the second threshold are introduced in the process of judging whether the pseudo-range observation of the current epoch is in a usable state. The second threshold is a value set based on a large amount of historical experience data or after multiple experiments. On this basis, referring to FIG5 , the above step S15 can be further implemented as the following steps.

S151, obtaining the pseudo-range observation value of each satellite in the current epoch, and the satellite-earth distance between the vehicle integrated navigation position in the current epoch and the position of each satellite.

S152, calculating a second difference between the pseudorange observation value of each satellite and the satellite-earth distance, and calculating a second standard deviation of all the second differences.

S153, judging whether the second standard deviation is less than a preset second threshold value. If so, the pseudo-range observation value is in an available state, otherwise, the pseudo-range observation value is in an unavailable state.

Since the satellite system used for navigation includes multiple satellites, for each satellite 120, the navigation receiver can also observe the pseudo-range observation value of the satellite, as well as the satellite-earth distance between the vehicle integrated navigation position of the previous epoch and the satellite position.

The calculation formula of the second difference can be expressed as: D _ρi =ρ _i -P _i .

The second differences of all satellites can be represented by a multi-dimensional matrix, which can be: M _m×1 = [ρ ₁ -P ₁ ,ρ ₂ -P ₂ .….ρ _m -P _m ], wherein m represents the number of available pseudorange observations.

The second standard deviation of all second differences can be expressed as: std(M _m×1 ), and the second threshold can be expressed as T _stdpsr . On this basis, when std(M _m×1 )<T _stdpsr is satisfied, the pseudorange observation is in an available state.

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., which is not specifically limited in this embodiment.

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

In the traditional integrated navigation method, the navigation receiver has clock errors for different satellites, resulting in poor positioning accuracy. In a possible implementation, in order to eliminate the clock error of the navigation receiver as much as possible and improve the positioning accuracy when using carrier phase differential observations for filtering estimation, inter-satellite difference and Kalman filtering are introduced. Specifically, referring to FIG6 , the above step S14 can be further implemented as the following steps.

S141: The satellite corresponding to the median of all the first differences is used as a reference satellite, and the first difference of the reference satellite is used as a first condition value.

S142, selecting, from the carrier phase differential observations of all satellites in the current epoch, a carrier phase differential observation whose difference between the first difference value and the first conditional value is less than a first deviation threshold as a selected observation.

S143, establishing a first measurement equation and a first state equation based on all selected observations.

S144, based on the first measurement equation and the first state equation, using Kalman filter estimation error estimation to obtain a first observation error.

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

Multidimensional matrix of first differences The satellite (i.e., reference satellite) corresponding to the median of is numbered ref1. The first difference value of the reference satellite is used as the first conditional value of the inter-satellite difference. The first conditional value can be expressed as: The first deviation threshold may be expressed as T _maxcp .

For the carrier phase difference observation of the i-th satellite, When , the carrier phase differential observation is the selected observation.

The first state equation can be expressed as:

In the first state equation,

And, X ₁ (t) = [δr, δv, δΨ, δb _a , δb _g , δt _ru ] ^T , is the first-order differential of X ₁ (t).

Among them, δr is the latitude and longitude position error in the northeast coordinate system, δv is the velocity error in the northeast coordinate system, δΨ is the attitude error, _δba is the accelerometer bias error, _δbg is the gyroscope bias error, _δtru is the observation error caused by the difference in the clock error between epochs of the navigation receiver, I is a 3×3 unit matrix, is the antisymmetric matrix of the Earth's rotation speed, is the rotation matrix from the carrier coordinate system to the navigation coordinate system, is the measurement value of the accelerometer in the carrier coordinate system, w(t) is the Gaussian white noise vector. The carrier can be a navigation receiver.

The first measurement equation can be expressed as: Z ₁ (t)=H ₁ (t)X ₁ (t)+v(t).

In the first measurement equation,

as well as,

Where v(t) is a Gaussian white noise vector.

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

In the above discrete Kalman filter calculation formula, is the state estimator of one-step transfer from t _k-1 to t _k , Φ _k/k-1 =I+F(t _k-1 )T, P _k/k-1 is the state error matrix of one-step transfer from t _k-1 to t _k , K _k is the filter gain matrix, P _k is the state error matrix at time t _k , Q _k-1 is the state noise matrix, and R _k-1 is the measurement noise matrix.

Substituting the above first measurement equation and the first state equation into the discrete Kalman filter calculation formula for calculation, the estimated first observation error can be obtained:

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

There are many different satellite systems used for navigation, such as the GPS system, the Galileo system, and the BeiDou system. However, navigation receivers process the raw observations of different satellite systems in different ways, resulting in different receiver clock error characteristics for different satellite systems.

In a possible implementation, in order to eliminate the error introduced by the navigation receiver due to different processing of different satellite systems, and to improve the positioning accuracy when filtering and estimating based on pseudorange, inter-satellite difference and Kalman filtering are introduced, and pseudorange observations are processed in subsystems. Specifically, referring to FIG. 7 , the above step S16 can be further implemented as the following steps.

S161: The satellite corresponding to the median of all the second differences is used as a reference satellite, and the second difference of the reference satellite is used as a second condition value.

S162, selecting, from the pseudorange observations of all satellites in the current epoch, a pseudorange observation whose difference between the second difference value and the second conditional value is less than a second deviation threshold as a selected observation.

S163, based on all selected observation quantities, establish a second measurement equation and a second state equation.

S164, based on the second measurement equation and the second state equation, using Kalman filter estimation error estimation to obtain a second observation error.

It should be noted that the second observation error may also include longitude and latitude position error, speed error and attitude error. The second deviation threshold is a value set based on a large amount of historical experience data or after multiple experiments.

The satellite (i.e., reference star) corresponding to the median of the multidimensional matrix of the second difference M _m×1 =[ρ ₁ -P ₁ ,ρ ₂ -P ₂ ,…,ρ _m -P _m ] is numbered ref2. The second difference of the reference star is used as the second conditional value of 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 .

For the pseudorange observation of the i-th satellite, when (ρ _i -P _i )-(ρ _ref -P _ref )<T _maxpsr , the pseudorange observation is the selected observation.

The second state equation can be expressed as:

In the second state equation, X ₂ (t) = [δr, δv, δΨ, _δba , _δbg , _δtgu , _δtcu ] ^T . _δtgu is the observation error caused by the clock error of the GPS navigation receiver. _δtcu is the observation error caused by the clock error of the Beidou navigation receiver. It should be understood that when the satellite system and the number of satellite systems change, The observation error caused by the navigation receiver clock error can be adjusted in X ₂ (t), for example, added, deleted or modified.

The second measurement equation can be expressed as: Z ₂ (t) = H ₂ (t) X ₂ (t) + v (t).

In the second measurement equation,

as well as,

in, represents the estimated distance between the nth satellite of the GPS system and the earth, e _gn represents the unit vector of the satellite position of the nth satellite of the GPS system, represents the estimated distance between the nth Beidou satellite and the earth, and e _cn represents the unit vector of the nth Beidou satellite's satellite-earth position.

Similarly, by substituting the above second measurement equation and the second state equation into the discrete Kalman filter calculation formula for calculation, the estimated second observation error can be obtained:

Through the above steps S161-S164, the reference star is used as the inter-satellite differential to eliminate the influence of the satellite clock error and the receiver clock error on the positioning based on the second conditional value of the reference star. 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.

After obtaining the estimated first observation error, second observation error or third observation error, the vehicle-mounted terminal compensates the position, speed and heading information obtained by strapdown solution according to the first observation error, second observation error or third observation error to obtain navigation information.

The strapdown solution includes attitude update method, velocity update method and position update method.

The posture update method can be expressed as:

Solving the above differential equation can update the current posture matrix, where is the angular velocity of the carrier system relative to the navigation system. The pitch angle, roll angle and heading angle of the carrier can be further solved through the attitude matrix.

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

The location update method can be expressed as:

Where:

Among them, L is latitude, _RM is the radius of the meridian circle, _RN is the radius of the meridian circle, and h is the altitude.

When the first observation error, the second observation error or the third observation error is obtained, each error amount is compensated to the navigation parameters such as attitude, position and speed obtained by strapdown solution through any compensation method such as addition and multiplication, so as to complete the compensation and obtain navigation information.

The vehicle-mounted strapdown combined navigation method provided by the disclosed embodiment realizes seamless switching of loose combination of velocity and position, tight combination of carrier phase difference and tight combination of pseudorange according to the satellite positioning status and the quality of the original observation information, thereby improving the combined navigation accuracy in complex scenarios. The measurement model of carrier phase difference is simplified, and the reference satellite is selected by the median method for inter-satellite difference to further eliminate the clock error of the navigation receiver and improve the navigation accuracy. At the same time, the receiver clock error estimation method of the 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 original pseudorange observation to further improve the navigation accuracy.

Based on the inventive concept of the above-mentioned vehicle-mounted strapdown integrated navigation method, in a possible implementation manner, the disclosed embodiment further provides a vehicle-mounted strapdown integrated navigation device 140, which can be applied to the vehicle-mounted terminal 130 in Figure 1. Referring to Figure 8, the vehicle-mounted strapdown integrated navigation device 140 may include a state determination module 150, an error estimation module 160 and a compensation module 170.

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

The error estimation module 160 is used to determine whether the carrier phase differential observation of the current epoch is in an available state when the PVT solution state is a floating point solution. If the carrier phase differential observation is in an available state, filtering estimation is performed based on the carrier phase differential observation to obtain a first observation error.

The error estimation module 160 is also used to determine whether the pseudorange observation of the current epoch is in an available state when the PVT solution state is pseudorange difference decomposition or single point solution. state, if the pseudorange observation amount is in an available state, filtering estimation is performed based on the pseudorange observation amount to obtain a second observation error.

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

The compensation module 170 is used to compensate the strapdown solution according to the first observation error, the second observation error or the third observation error to obtain navigation information.

In the above-mentioned vehicle-mounted strapdown combined navigation device 140, through the coordinated action of the state determination module 150, the error estimation module 160 and the compensation module 170, according to the positioning state and the quality of the observation quantity, the position velocity observation quantity, the carrier phase difference observation quantity or the pseudo-range observation quantity is switched to perform error estimation, and the strapdown solution is compensated based on the estimated observation error to obtain navigation information, which can reduce the influence of the multipath effect as much as possible, and greatly improve the positioning accuracy and navigation accuracy in complex scenes.

Can refer to the limitation for the vehicle-mounted strapdown combined navigation method above about the specific limitation of vehicle-mounted strapdown combined navigation device 140, repeat no more at this.Each module in the above-mentioned vehicle-mounted strapdown combined navigation device 140 can be realized in whole or in part by software, hardware and combination thereof.Above-mentioned each module can be embedded in or be independent of the processor in the electronic device in hardware form, also can be stored in the memory of the electronic device in software form, so that the processor calls the operation corresponding to each above module.

In one embodiment, an electronic device 180 is provided, which can be a terminal, and its internal structure diagram can be shown in Figure 9. The electronic device 180 includes a processor, a memory, a communication interface, a display screen and an input device connected by a system bus. Among them, the processor of the electronic device 180 is used to provide computing and control capabilities. The memory of the electronic device 180 includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the electronic device 180 is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, an operator network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, the vehicle-mounted strapdown combined navigation method provided in the above embodiment is implemented.

The structure shown in FIG9 is merely a block diagram of a partial structure related to the scheme of the present disclosure, and does not constitute a limitation on the electronic device 180 to which the scheme of the present disclosure is applied. The specific electronic device 180 may include more or fewer components than those shown in FIG9 , or combine certain components, or have a different arrangement of components.

In one embodiment, the vehicle-mounted strapdown integrated navigation device 140 provided by the present disclosure can be implemented in the form of a computer program, and the computer program can be run on an electronic device 180 as shown in Figure 9. The memory of the electronic device 180 can store various program modules constituting the vehicle-mounted strapdown integrated navigation device 140, such as the state determination module 150, the error estimation module 160 and the compensation module 170 shown in Figure 8. The computer program composed of the various program modules enables the processor to execute the steps in the vehicle-mounted strapdown integrated navigation method described in this specification.

For example, the electronic device 180 shown in FIG9 may perform step S11 through the state determination module 150 in the vehicle-mounted strapdown integrated navigation device 140 shown in FIG8 . The electronic device 180 may perform steps S12-S16 through the error estimation module 160 . The electronic device 180 may perform step S17 through the compensation module 170 .

In one embodiment, an electronic device 180 is provided, including a memory and a processor, the memory storing a computer program, and the processor implementing the following steps when executing the computer program: obtaining 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, and if the carrier phase differential observation is in an available state, filtering and estimating 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, and if the pseudorange observation is in an available state, filtering and estimating based on the pseudorange observation to obtain a second observation error; when the PVT solution state is a fixed solution, filtering and estimating based on the position and velocity observation of the current epoch to obtain a third observation error; and compensating for the strapdown solution according to the first observation error, the second observation error, or the third observation error to obtain navigation information.

In one embodiment, a storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented: obtaining 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, and if the carrier phase differential observation is in an available state, filtering and estimating based on the carrier phase differential observation to obtain a first observation error; when the PVT solution state is a pseudorange difference decomposition or a single-point solution, determining whether the pseudorange observation of the current epoch is in an available state, and if the pseudorange observation is in an available state, filtering and estimating based on the pseudorange observation to obtain a second observation error; when the PVT solution state is a fixed solution, filtering and estimating based on the position and velocity observation of the current epoch to obtain a third observation error; and compensating for the strapdown solution according to the first observation error, the second observation error, or the third observation error to obtain navigation information.

In the several embodiments provided in the present disclosure, it should be understood that the disclosed devices and methods may also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of the devices, methods, and computer program products according to the multiple embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram may represent a module, a program segment, or a portion of a code, and the module, program segment, or a portion of a code contains 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 boxes may also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes may actually be executed substantially in parallel, and they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that the block diagrams and/or flowcharts Each block in the block diagram, and combinations of blocks in the block diagram and/or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

In addition, the functional modules in the various embodiments of the present disclosure may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

If the functions are implemented in the form of software function 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 the present disclosure, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present disclosure. The aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program codes.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Industrial Applicability

The present invention provides a vehicle-mounted strapdown integrated navigation method, which includes: obtaining a PVT solution state of a navigation receiver; when the PVT solution state is a floating point solution, judging whether a carrier phase differential observation quantity of a current epoch is in an available state; if the carrier phase differential observation quantity is in an available state, filtering and estimating based on the carrier phase differential observation quantity to obtain a first observation error; when the PVT solution state is a pseudorange differential decomposition or a single point solution, judging whether a pseudorange observation quantity of the current epoch is in an available state; if the pseudorange observation quantity is in an available state, filtering and estimating based on the pseudorange observation quantity to obtain a second observation error; when the PVT solution state is a fixed solution, filtering and estimating based on a position velocity observation quantity of the current epoch to obtain a third observation error; and compensating the strapdown solution according to the first observation error, the second observation error or the third observation error to obtain navigation information. According to the vehicle-mounted strapdown combined navigation method provided by the present invention, according to the positioning state and the quality of the observation quantity, the position and velocity observation quantity, the carrier phase difference observation quantity or the pseudo-range observation quantity is switched to perform error estimation, and the strapdown solution is compensated based on the estimated observation error to obtain navigation information, so that different observation quantities are switched to perform error estimation according to the positioning state and the quality of the observation quantity for navigation, which can reduce the influence of the multipath effect as much as possible and greatly improve the positioning accuracy and navigation accuracy in complex scenarios.

In addition, it is understood that the vehicle-mounted strapdown integrated navigation method provided by the present disclosure is reproducible and can be used in a variety of industrial applications. For example, the vehicle-mounted strapdown integrated navigation method, device, electronic device and storage medium provided by the present disclosure can be applied to the field of navigation technology.

Claims

A vehicle-mounted strapdown integrated navigation method, characterized in that the method comprises:

Get the PVT solution status of the navigation receiver;

When the PVT solution state is a floating point solution, determining whether the carrier phase differential observation quantity of the current epoch is in an available state;

If the carrier phase differential observation amount is in an available state, filtering estimation is performed based on the carrier phase differential observation amount to obtain a first observation error;

When the PVT solution state is pseudorange difference decomposition or single point solution, determining whether the pseudorange observation quantity of the current epoch is in an available state;

If the pseudorange observation value is in an available state, filtering estimation is performed based on the pseudorange observation value to obtain a second observation error;

When the PVT solution state is a fixed solution, filtering estimation is performed based on the position and velocity observations of the current epoch to obtain a third observation error;

The strapdown solution is compensated according to the first observation error, the second observation error or the third observation error to obtain navigation information.
The vehicle-mounted strapdown integrated navigation method according to claim 1, characterized in that the method further comprises:

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

If the pseudo-range observations are all in an unavailable state, the dead reckoning algorithm is used to obtain navigation information.
The vehicle-mounted strapdown integrated navigation method according to any one of claims 1 to 3 is characterized in that the step of determining whether the carrier phase differential observation quantity of the current epoch is in an available state comprises:

Obtain the carrier phase difference observation and satellite-earth 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;

Calculating the product of the position vector and the satellite-earth position unit vector, calculating a first difference between the carrier phase differential observation of each satellite and the product, and calculating a first standard deviation of all the first differences;

It is determined whether the first standard deviation is less than a preset first threshold value. If so, the carrier phase differential observation amount is in an available state; otherwise, the carrier phase differential observation amount is not in an available state.
The vehicle-mounted strapdown integrated navigation method according to any one of claims 1 to 3 is characterized in that the step of determining whether the pseudorange observation amount of the current epoch is in an available state comprises:

Obtain the pseudorange observation of each satellite in the current epoch, as well as the satellite-earth distance between the vehicle integrated navigation position in the current epoch and the position of each satellite;

Calculating a second difference between the pseudorange observation value of each satellite and the satellite-earth distance, and calculating a second standard deviation of all the second differences;

It is determined whether the second standard deviation is less than a preset second threshold value. If so, the pseudorange observation value is in an available state.
The vehicle-mounted strapdown integrated navigation method according to claim 4 is characterized in that the step of performing filtering estimation based on the carrier phase differential observation to obtain the first observation error comprises:

Using the satellite corresponding to the median of all the first differences as a reference star, and using the first difference of the reference star as a first condition value;

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

Based on all the selected observation quantities, establishing a first measurement equation and a first state equation;

Based on the first measurement equation and the first state equation, a Kalman filter estimation error is used to obtain a first observation error; wherein the first observation error includes a longitude and latitude position error, a speed error, and an attitude error.
The vehicle-mounted strapdown integrated navigation method according to claim 5 is characterized in that the step of performing filtering estimation based on the pseudorange observation to obtain the second observation error comprises:

The satellite corresponding to the median of all the second difference values is used as a reference satellite, and the second difference value of the reference satellite is used as a second condition value;

From the pseudorange observations of all satellites in the current epoch, select as the selected observation, a pseudorange observation whose difference between the second difference and the second condition value is less than a second deviation threshold;

Based on all the selected observation quantities, establishing a second measurement equation and a second state equation;

Based on the second measurement equation and the second state equation, Kalman filter estimation error estimation is adopted to obtain a second observation error; wherein the second observation error includes longitude and latitude position error, velocity error and attitude error.
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 solution according to the first observation error, the second observation error or the third observation error to obtain navigation information comprises:

The position, speed and heading information obtained by strapdown solution are compensated according to the first observation error, the second observation error or the third observation error to obtain navigation information.
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 comprises:

The PVT solution state is determined according to the state flag of the PVT solution of the navigation receiver.
The vehicle-mounted strapdown integrated navigation method according to claim 4, characterized in that the calculation formula of the first difference includes:

in, represents the first difference of the i-th satellite, represents the carrier phase differential observation of the ith satellite, e i represents the satellite-to-earth position unit vector from the position coordinates of the ith 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.
The vehicle-mounted strapdown integrated navigation method according to claim 5, characterized in that the calculation formula of the second difference includes:
D ρi = ρi - P i

Wherein, D ρi represents the second difference of the i-th satellite, ρi represents the pseudo-range observation of the i-th satellite, and Pi represents the satellite-earth distance between the vehicle's integrated navigation position and the i-th satellite.
A vehicle-mounted strapdown integrated navigation device, characterized in that it comprises 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 amount of the current epoch is in an available state when the PVT solution state is a floating point solution, and if the carrier phase differential observation amount is in an available state, perform filtering estimation based on the carrier phase differential observation amount to obtain a first observation error;

The error estimation module is further configured to, when the PVT solution state is pseudorange difference decomposition or single point solution, determine whether the pseudorange observation amount of the current epoch is in an available state, and if the pseudorange observation amount is in an available state, perform filtering estimation based on the pseudorange observation amount to obtain a second observation error;

The error estimation module is further used to perform filtering estimation based on the position and velocity observations of the current epoch to obtain a third observation error when the PVT solution state is a fixed solution;

The compensation module is used to compensate the strapdown solution according to the first observation error, the second observation error or the third observation error to obtain navigation information.
An electronic device, characterized in that it includes a processor and a memory, wherein the memory stores a computer program that can be executed by the processor, and the processor can execute the computer program to implement the vehicle-mounted strapdown combination method as described in any one of claims 1 to 11.
A storage medium having a computer program stored thereon, characterized in that when the computer program is executed by a processor, the vehicle-mounted strapdown combination method according to any one of claims 1 to 11 is implemented.