WO2021027621A1

WO2021027621A1 - Navigation method, apparatus device, electronic device, and storage medium

Info

Publication number: WO2021027621A1
Application number: PCT/CN2020/106747
Authority: WO
Inventors: 李志杰
Original assignee: Oppo广东移动通信有限公司
Priority date: 2019-08-14
Filing date: 2020-08-04
Publication date: 2021-02-18
Also published as: CN112394377A; CN112394377B

Abstract

A navigation method, a navigation apparatus, an electronic device, and a storage medium. The navigation method comprises: obtaining measured values of a pseudo range and a pseudo range rate of a global positioning system (101); obtaining predicted values of a pseudo range and a pseudo range rate of an inertial navigation system at the same moment as the global positioning system (102); calculating measurement information of a combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudo range and the pseudo range rate and the predicted values of the pseudo range and the pseudo range rate (103); and eliminating a time synchronization error between the inertial navigation system and the global positioning system according to the measurement information to correct positioning of the combined positioning system of the global positioning system and the inertial navigation system (104). Navigation precision and positioning speed are improved.

Description

Navigation method, device equipment, electronic equipment and storage medium

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office, the application number is 201910749943.7, and the application name is "navigation method, device, electronic equipment and storage medium" on August 14, 2019. The entire content is incorporated by reference. In this application.

Technical field

This application relates to the field of communication technology, and in particular to a navigation method, device, electronic equipment and storage medium.

Background technique

Integrated navigation refers to a navigation system that integrates various navigation equipment and is controlled by a monitor and a computer. Most integrated navigation systems are mainly inertial navigation systems (INS, Inertial Navigation System). The main reason is that inertial navigation can provide more navigation parameters, and can also provide full attitude information parameters, which is unmatched by other navigation systems. Yes, it also needs the Global Positioning System (GPS) as an auxiliary role.

The current time synchronization error of GPS/INS integrated navigation. The software solution to solve the time synchronization error of GPS/INS integrated navigation is to estimate its existing time synchronization error as the state of the Kalman filter, and the loose combination of INS/GPS The method has certain limitations, such as the problem of filter cascade in loose combination, and the statistical observability of INS error is relatively weak. What's more, when the GPS alone navigation solution cannot be obtained due to the insufficient number of visible satellites, the GPS/INS loose integrated navigation fails. The GPS/INS tight integrated navigation is derived from this, but the existing GPS/INS tight integrated navigation also has time synchronization errors, and for a single satellite single calculation, its pseudorange, pseudorange rate and pseudorange rate derivative The arithmetic calculation is more complicated, and it is slow to obtain an accurate navigation position.

Application content

The embodiments of the present application provide a navigation method, device, electronic equipment, and storage medium, which can eliminate time synchronization errors in a GPS/INS tight integrated navigation system, and improve navigation accuracy and positioning speed.

In the first aspect, an embodiment of the present application provides a navigation method, and the navigation method includes:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

Acquiring the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system;

Calculating the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate;

The time synchronization error between the inertial navigation system and the global positioning system is eliminated according to the measurement information to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

In the second aspect, an embodiment of the present application provides a navigation device, and the navigation device includes:

The first acquiring module is used to acquire the measured values of the pseudorange and pseudorange rate of the global positioning system;

The second acquiring module is used to acquire the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system simultaneously engraved with the global positioning system;

A calculation module for calculating the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate;

The correction module is used to eliminate the time synchronization error between the inertial navigation system and the global positioning system according to the measurement information, so as to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

In a third aspect, an embodiment of the present application provides an electronic device including a processor and a memory, the memory stores a plurality of instructions, and the processor loads the instructions in the memory to perform the following steps:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

In a fourth aspect, an embodiment of the present application provides a storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps in the above navigation method are implemented.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic diagram of the first flow of a navigation method provided by an embodiment of the present application.

Fig. 2 is a schematic diagram of a second flow of a navigation method provided by an embodiment of the present application.

Fig. 3 is a schematic diagram of a scene of a navigation method provided by an embodiment of the present application.

Figure 4 is an error comparison curve diagram provided by an embodiment of the present application.

Fig. 5 is a first structural diagram of a navigation device provided by an embodiment of the present application.

FIG. 6 is a schematic diagram of a second structure of a navigation device provided by an embodiment of the present application.

FIG. 7 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of this application.

In the following description, specific embodiments of the present application will be described with reference to steps and symbols executed by one or more computers, unless otherwise stated. Therefore, these steps and operations will be mentioned several times as being executed by a computer. The computer execution referred to in this article includes the operation of a computer processing unit that represents an electronic signal of data in a structured form. This operation converts the data or maintains it in a position in the computer's memory system, which can be reconfigured or otherwise changed the operation of the computer in a manner well known to testers in the art. The data structure maintained by the data is the physical location of the memory, which has specific characteristics defined by the data format. However, the principle of this application is described in the above text, which does not represent a limitation. Testers in the field will understand that the various steps and operations described below can also be implemented in hardware.

The terms "first", "second" and "third" in this application are used to distinguish different objects, rather than describing a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the listed steps or modules, but some embodiments also include steps or modules that are not listed, or some embodiments It also includes other steps or modules inherent to these processes, methods, products, or equipment.

The embodiments of the present application provide a navigation method, device, electronic equipment, and storage medium. Detailed descriptions are given below.

GPS (Global Positioning System, Global Positioning System) is currently the most widely used satellite navigation and positioning system. It is easy to use and low in cost. Its latest actual positioning accuracy has reached within 5 meters. However, military applications of GPS systems still have disadvantages such as susceptibility to interference, poor reliability in dynamic environments, and low data output frequency.

The currently adopted method is to combine a GPS navigation system and an INS navigation system (Inertial Navigation System, inertial navigation system) to form a GPS/INS integrated navigation system. At present, GPS/INS integrated navigation systems include GPS/INS tight integrated navigation systems and GPS/INS loose integrated navigation systems.

In these two integrated navigation systems, there is a time synchronization error between the GPS navigation system and the INS navigation system, which will cause the problem of inaccurate positioning during the navigation process.

The embodiment of the present application provides a navigation method, the method includes:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

In an embodiment, the obtaining the measured values of the pseudorange and the pseudorange rate of the global positioning system includes:

Acquire the pseudo-range measurement value of the global positioning system according to the first preset algorithm, and obtain the pseudo-range rate measurement value of the global positioning system according to the second preset algorithm.

In an embodiment, the acquiring the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system includes:

Acquiring the system parameters of the combined positioning system of the global positioning system and the inertial navigation system, the system parameters including the navigation solution, satellite parameters, clock offset and clock drift of the inertial navigation system;

Calculate the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system according to the system parameters.

In an embodiment, calculating the pseudorange and pseudorange rate predicted values of the inertial navigation system simultaneously with the global positioning system according to the system parameters includes:

Performing lever arm coordinate conversion on the navigation solution of the inertial navigation system to obtain a first conversion value and a second conversion value;

The predicted value of the pseudorange and pseudorange rate of the inertial navigation system simultaneously engraved with the global positioning system is calculated according to the first conversion value, the second conversion value, and the unit line-of-sight distance vector of the satellite and the electronic device.

In an embodiment, performing lever arm coordinate conversion on the navigation solution of the inertial navigation system to obtain the first conversion value and the second conversion value includes:

The navigation solution of the inertial navigation system is converted by lever arm coordinates to obtain the first conversion value and the second conversion value. The conversion formula is as follows:

among them,

Is the first converted value,

Is the second conversion value, Ω is the angular velocity vector antisymmetric matrix, C is the coordinate conversion matrix, L is the phase center lever arm between systems, and W is the system noise vector.

In an embodiment, the calculation of the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted value of the pseudorange and the pseudorange rate includes :

Acquiring the sampling data of the GPS pseudorange and the pseudorange rate during the sampling period of the inertial navigation system according to the measured values of the GPS pseudorange and the pseudorange rate and the Taylor formula;

The measurement information in the sampling period is acquired according to the sampling data of the pseudorange and pseudorange rate of the global positioning system and the sampling data of the pseudorange and the pseudorange rate of the inertial navigation system within the sampling period of the inertial navigation system.

In an embodiment, the time synchronization error of the combined positioning system of the global positioning system and the inertial navigation system is eliminated according to the measurement information to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system, include:

Linearize the measurement vector according to the measurement information and the extended Kalman filter to obtain a measurement matrix;

The time synchronization error between the global positioning system and the inertial navigation system is obtained according to the measurement matrix, and the time synchronization error is eliminated to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

The navigation method in the embodiment of the present application eliminates the time synchronization error in the GPS/INS tight integrated navigation system to improve the navigation accuracy and positioning speed of the GPS/INS tight integrated navigation system. Please refer to FIG. 1 for details. FIG. 1 is a first flowchart of a navigation method provided by an embodiment of the present application.

In step 101, the measured values of the pseudorange and the pseudorange rate of the global positioning system are obtained.

Pseudo-range refers to the approximate distance between the ground receiver and the satellite during satellite positioning. Assuming that the satellite clock and the receiver clock are strictly synchronized, the propagation time of the signal can be obtained according to the transmission time of the satellite signal and the reception time of the signal received by the receiver, and then multiplied by the propagation speed to obtain the satellite-to-ground distance. However, there is inevitably a clock difference between the two clocks, and the signal is also affected by factors such as atmospheric refraction during propagation. Therefore, the distance directly measured by this method is not equal to the true distance between the satellite and the ground receiver. This distance is called pseudorange.

Using the principle of distance triangle measurement, the user’s GPS receiver receives the signals of 4 satellites at the same time, and can calculate the three-dimensional space position of the user’s GPS receiver; at the same time, the distance obtained during the measurement time is used to differentiate in time, based on the linear velocity and In relation to the Doppler frequency, the user's GPS receiver can calculate the Doppler frequency of the satellite, thereby calculating its own movement speed. Because the clock reference of the user receiver has an error relative to the GPS atomic clock reference, the actual measurement distance is called "pseudo range", and the pseudo range will be differentiated within the actual measurement time interval. The speed measurement value is called "Delta pseudo range" (Delta pseudo range), also known as "Pseudo range rate".

The measured values of the pseudo-range and pseudo-range rate of the global positioning system can be obtained from the GPS ranging processor, where the pseudo-range measurement value of the GPS navigation system can be obtained, which can be obtained by the first preset algorithm, for example, GPS is obtained by code tracking Pseudorange measurement value in the ranging processor.

Obtaining the pseudo-range rate measurement value of the GPS navigation system may be obtained by a second preset algorithm, for example, obtaining the pseudo-range rate measurement value in the GPS ranging processor from the carrier wave. It should be noted that the first preset algorithm and the second preset algorithm are not limited to the aforementioned algorithms.

In some embodiments, the pseudorange and pseudorange rate in the GPS navigation system may also be measured values actively output by the GPS ranging processor.

In step 102, the predicted values of the pseudo-range and pseudo-range rate of the inertial navigation system at the same time as the global positioning system are obtained.

In an embodiment, the pseudorange and pseudorange rate predicted values of the inertial navigation system at the same time as the global positioning system can be obtained according to the system parameters in the INS navigation system, where the system parameters may include the parameters of the INS navigation system. Inertial navigation solution, estimated clock offset and clock drift, and satellite parameters. The satellite parameters include the position and speed of the satellite calculated by the telegram.

In an embodiment, the inertial navigation solution of the INS navigation system can be converted by lever arm coordinates to obtain the first conversion value and the second conversion value, according to the first conversion value, the second conversion value and the unit of the satellite and the electronic device The line-of-sight distance vector is used to calculate the pseudorange and pseudorange rate estimates of the INS navigation system.

In step 103, the measurement information of the combined positioning system of the global positioning system and the inertial navigation system is calculated according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate.

It is understandable that due to the different sampling frequencies of the GPS navigation system and the INS navigation system and the time delay in the transmission of information to the combined filter, the GPS pseudorange, the pseudorange rate measurement value, and the pseudorange predicted by parameters such as the INS navigation solution There is a time synchronization problem between the estimated value of the range and pseudorange rate.

At this time, the measurement information can be obtained according to the measured values of the pseudorange and pseudorange rate of the GPS navigation system and the predicted values of the pseudorange and pseudorange rate of the INS navigation system obtained above. For example, the difference between the measured value of the pseudorange of the GPS navigation system and the predicted value of the pseudorange of the INS navigation system, and the difference between the measured value of the pseudorange rate of the GPS navigation system and the predicted value of the pseudorange rate of the INS navigation system, You can get the measurement information.

In step 104, the time synchronization error between the inertial navigation system and the global positioning system is eliminated according to the measurement information to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

In an embodiment, after the measurement information is obtained, the time synchronization error between the INS navigation system and the GPS navigation system can be obtained according to the measurement information, and then the time synchronization error is eliminated to improve the GPS/INS tight integrated navigation system The time synchronization error is corrected to obtain accurate positioning information.

The measurement information can be used to include some error parameters between the INS navigation system and the GPS navigation system. The error parameters include the error between the GPS navigation system and the INS navigation system, such as time synchronization error, positioning position, speed and other errors. .

Specifically, the measurement information can be used to calculate the measurement vector and the error state vector, and the measurement innovation can be used to update the error state vector to obtain the position, velocity, and attitude error state solution at the target time, as well as the IMU (Inertial Measurement Unit, inertial measurement unit). Unit) zero offset, clock deviation and drift of electronic equipment.

Finally, these errors are eliminated to correct the time synchronization errors of the GPS/INS tight integrated navigation system. Wherein, the correction method may be to obtain time synchronization error correction values at multiple times, calculate the average value of multiple time synchronization error correction values, and then correct the time synchronization error based on the average value.

In an embodiment, it is also possible to learn and analyze the time synchronization error of multiple corrections by means of deep learning, and then when the time synchronization error is obtained, the time synchronization error can be corrected according to the historical correction method.

After correcting the time synchronization error between the GPS navigation system and the INS navigation system, the GPS/INS tight integrated navigation system can obtain accurate positioning information, thereby improving navigation accuracy and positioning speed.

The embodiment of the application obtains the pseudo-range and pseudo-range rate measurement values of the global positioning system, and obtains the pseudo-range and pseudo-range rate predicted values of the inertial navigation system engraved at the same time as the global positioning system. The measured value of the pseudo-range rate and the predicted value of the pseudo-range rate and the predicted value of the pseudo-range rate calculate the measurement information of the combined positioning system of the global positioning system and the inertial navigation system, and compare the inertial navigation system and the global positioning system based on the measurement information. The time synchronization error of the positioning system is eliminated to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system. By eliminating the time synchronization error between the global positioning system and the inertial navigation system, navigation accuracy and positioning speed are improved.

Please refer to FIG. 2, which is a schematic diagram of a second flow of the navigation method provided by an embodiment of the present application. The navigation method in the embodiment of the present application eliminates the time synchronization error in the GPS/INS tight integrated navigation system to improve the navigation accuracy and positioning speed of the GPS/INS tight integrated navigation system.

In step 201, the measured values of the pseudorange and the pseudorange rate of the global positioning system are obtained. This step is the same as step 101 and will not be repeated here.

In step 202, the system parameters of the combined positioning system of the global positioning system and the inertial navigation system are obtained, and the system parameters include the navigation solution of the inertial navigation system, satellite parameters, clock offset and clock drift.

It is understandable that the predicted values of the pseudorange and pseudorange rate of the inertial navigation system cannot be directly output from the inertial navigation processor, and calculations are needed to obtain the predicted values of the pseudorange and pseudorange rate of the inertial navigation system. It should be noted that the satellite parameters include the position and speed of the satellite.

In step 203, the predicted values of the pseudorange and pseudorange rate of the inertial navigation system at the same time as the global positioning system are calculated according to the system parameters.

In an embodiment, the current attitude, speed, and position in the inertial navigation system can be obtained by calculating the data output by the inertial measurement unit (IMU), and then the message obtained by the satellite receiving system can be solved to obtain the satellite position, The speed and other information, and finally calculate the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system based on the satellite position, speed and the position and speed information of the inertial navigation system.

In an embodiment, the unit line-of-sight distance vector between the satellite and the user and the navigation solution in the inertial navigation system may be used to obtain the estimated value of the pseudorange and the pseudorange rate of the inertial navigation system.

For example, first convert the navigation solution of the inertial navigation system to obtain the first conversion value and the second conversion value through the lever arm coordinate conversion. The conversion formula is as follows:

among them,

Is the first converted value,

Then, according to the second conversion value and the unit line-of-sight distance vector between the satellite and the user, the state vector estimated by the inertial navigation system (position vector, velocity vector, partial derivative of time error) is calculated, and the estimated state vector can be used to calculate Output speed, acceleration and jerk. The formula is as follows:

Where u _k is the unit line-of-sight distance vector between the satellite and the user.

Finally, according to the position and speed output from the satellite and the inertial measurement unit, the predicted value of the pseudorange and pseudorange rate of the inertial navigation system is obtained. The obtained pseudorange and pseudorange rate predicted value formulas of the inertial navigation system are as follows:

among them

Is the pseudorange prediction value of the inertial navigation system,

It is the measured value of the pseudo-range rate of the inertial navigation system. The superscript l represents the lever arm coordinate system, i represents the inertial coordinate system, e represents the geocentric ground-fixed coordinate system, j represents the number of satellites, and a represents the parameters of the satellite attributes , A is acceleration, C is coordinate conversion matrix, U is unit vector and line-of-sight unit vector.

In step 204, the sampling data of the GPS pseudorange and the pseudorange rate during the sampling period of the inertial navigation system are acquired according to the measured values of the GPS pseudorange and the pseudorange rate and the Taylor formula.

Due to the difference in sampling frequency between the GPS navigation system and the INS navigation system and the delay in the transmission of information to the combined filter, the pseudorange and pseudorange rate measured values of the GPS navigation system and the INS navigation system predicted by parameters such as the INS navigation solution There is a time synchronization problem between the pseudorange and pseudorange rate, that is, time synchronization error.

At this time, it is necessary to expand the corresponding pseudorange and pseudorange rate using Taylor formula to predict the pseudorange and pseudorange rate of GPS and inertial navigation at the same time, and then perform corresponding data processing.

First, when the pseudorange and pseudorange rate of the GPS navigation system are at t=kT _s , they are expanded using Taylor's formula and retained to the second order, where T _s is the sampling period of the INS navigation system to obtain the pseudorange of the GPS navigation system The sum pseudorange rate can be expressed by the following formula:

When t=kT _s -δt, the pseudorange and pseudorange rate of the GPS navigation system can be expressed by the following formula:

It’s important to note that

Is the pseudorange measurement value of the GPS navigation system,

Is the measured value of the pseudorange rate of the GPS navigation system, where δt is the time synchronization error between the GPS navigation system and the INS navigation system.

In step 205, the measurement information in the sampling period is acquired according to the sampling data of the GPS pseudorange and pseudorange rate and the sampling data of the inertial navigation system pseudorange and pseudorange rate within the inertial navigation system sampling period.

In an embodiment, the measured values of the pseudorange and pseudorange rate of the GPS navigation system at a certain moment can be obtained, and the pseudorange and pseudorange rate predicted values of the INS navigation system engraved at the same time as the GPS navigation system can be obtained, and then the The measured value of the pseudorange and the predicted value are made difference, and the measured value of the pseudorange rate and the predicted value are made difference to obtain measurement information. The measurement information matrix obtained is as follows:

Where k is the kth sampling time, Z is the measurement vector, m is the number of satellites,

Indicates the measurement information of the pseudorange,

Indicates the measurement information of the pseudorange rate.

In an embodiment, the measurement information in the sampling period T _s of the INS navigation system may be acquired to analyze the time synchronization error in the sampling period T _s of the INS navigation system.

In step 206, the measurement vector is linearized according to the measurement information and the extended Kalman filter to obtain a measurement matrix.

The measurement vector is a non-linear function about the error state vector, which can be linearized by using Extended Kalman filter (EFK, Extended Kalman filter) to grasp the law of sampling data change and obtain the measurement matrix. Among them, the extended Kalman filter linearization formula for:

In one embodiment, the pseudorange and pseudorange rate are weakly correlated with attitude error, acceleration zero offset, and gyro zero offset. Pseudorange is also weakly correlated with velocity error, and pseudorange rate with position error. These items are ignored during matrix linearization, and the approximate measurement matrix obtained is:

The time synchronization error between the GPS navigation system and the INS navigation system can be obtained according to the approximate measurement matrix.

In step 207, the time synchronization error between the global positioning system and the inertial navigation system is obtained according to the measurement matrix, and the time synchronization error is eliminated to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

After the time synchronization error is obtained, the time synchronization error between the INS navigation system and the GPS navigation system in the sampling period can be eliminated, so that the GPS/INS tight integrated navigation system can accurately locate. In addition, it is recorded by the embodiment of this application. The navigation method can reduce the amount of calculation when calculating the time synchronization error, so as to realize the fast positioning function.

In an embodiment, the method of correction may be to obtain time synchronization error correction values at multiple times, calculate the average value of multiple time synchronization error correction values, and then correct the time synchronization error according to the average value. .

The embodiment of the application obtains the pseudorange and pseudorange rate measurement values of the global positioning system, and obtains the pseudorange and pseudorange rate predicted values of the inertial navigation system engraved simultaneously with the global positioning system, according to the global positioning system The measured values of the pseudo-range and the pseudo-range rate and the Taylor formula acquire the sampling data of the GPS pseudo-range and the pseudo-range rate during the sampling period of the inertial navigation system, according to the global positioning system pseudo-range and the pseudo-range rate The sampling data of the inertial navigation system and the sampling data of the pseudo-range and the pseudo-range rate of the inertial navigation system within the sampling period of the inertial navigation system acquire measurement information during the sampling period.

Finally, the measurement vector is linearized according to the measurement information and the extended Kalman filter to obtain the measurement moment, and then the time synchronization error between the global positioning system and the inertial navigation system is obtained according to the measurement matrix, and the time synchronization is performed The error is eliminated to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

By eliminating the time synchronization error between the global positioning system and the inertial navigation system, navigation accuracy and positioning speed are improved.

Please refer to FIG. 3, which is a schematic diagram of a scene of a navigation method provided by an embodiment of the present application. In Figure 3, a three-dimensional fully dynamic carrier motion track including acceleration, deceleration, turning and climbing is designed, and then the time synchronization error and other errors between the INS navigation system and the GPS navigation system are obtained.

Considering the time synchronization error, the system equations and measurement equations of the GPS/INS tight combination are simulated. Obtain the error analysis data in the following table:

Among them, Max is the maximum error value, SD is the average error value, and Mean is the minimum error value.

Please refer to FIG. 4 for details. FIG. 4 is an error comparison curve diagram provided by an embodiment of the present application, where curve A is an error curve without compensation for time synchronization error, and curve B is an error curve for compensation for time synchronization error.

It can be seen from Figure 4 that through the above-mentioned navigation method, the time synchronization error of the GPS/INS navigation system is compensated, and the positioning and speed fix performance of the navigation system is significantly improved. It can also be seen that the impact of time asynchrony on the navigation performance is more The dynamic level of the carrier is related. The higher the dynamic level of the carrier, that is, the greater the speed and acceleration, the more prominent the time synchronization problem. The model designed based on the distance domain can effectively suppress the time synchronization problem, and the compensated position and velocity errors are basically the same as those without time synchronization problems.

Correspondingly, an embodiment of the present application also provides a navigation device, as shown in FIG. 5 for a first structural diagram of the navigation device. The navigation device includes: a first acquisition module 510, a second acquisition module 520, a calculation module 530, and a correction module 540.

Wherein, the first obtaining module 510 is used to obtain the measured values of the pseudorange and the pseudorange rate of the global positioning system.

The first obtaining module 510 may use a first preset algorithm to obtain, for example, code tracking to obtain the pseudorange measurement value in the GPS ranging processor.

The second obtaining module 520 is used to obtain the predicted values of the pseudorange and the pseudorange rate of the inertial navigation system at the same time as the global positioning system.

In an embodiment, the second obtaining module 520 is specifically configured to obtain the pseudorange measurement value of the global positioning system according to the first preset algorithm, and obtain the pseudorange rate measurement value of the global positioning system according to the second preset algorithm.

It should be noted that the second acquisition module 520 also includes an acquisition sub-module 521 and a first calculation sub-module 522. For details, please refer to FIG. 6, which is a schematic diagram of a second structure of the navigation device according to an embodiment of the present application.

Wherein, the acquisition sub-module 521 is used to acquire system parameters of the combined positioning system of the global positioning system and the inertial navigation system. The system parameters include the navigation solution, satellite parameters, clock offset and clock drift of the inertial navigation system.

It is understandable that the predicted values of the pseudorange and pseudorange rate of the inertial navigation system cannot be directly output from the inertial navigation processor, and calculations are needed to obtain the predicted values of the pseudorange and pseudorange rate of the inertial navigation system. The system parameters of the combined positioning system of the global positioning system and the inertial navigation system can be acquired through the acquisition submodule 521. It should be noted that the satellite parameters include parameters such as the position and speed of the satellite.

The first calculation sub-module 522 is configured to calculate, according to the system parameters, the predicted values of the pseudorange and the pseudorange rate of the inertial navigation system at the same time as the global positioning system.

In an embodiment, the first calculation sub-module 522 may be used to calculate the data output by the inertial measurement unit (IMU) to obtain the current attitude, speed, and position in the inertial navigation system, and then to resolve the message obtained by the satellite receiving system Calculate, obtain the satellite position, speed and other information, and finally calculate the pseudorange and pseudorange rate predicted value of the inertial navigation system according to the satellite position, velocity and the position and velocity information of the inertial navigation system.

In an embodiment, the first calculation sub-module 522 may use the unit line-of-sight distance vector between the satellite and the user and the navigation solution in the inertial navigation system to obtain the estimated value of the pseudorange and the pseudorange rate of the inertial navigation system.

among them,

Is the first converted value,

among them

Is the pseudorange prediction value of the inertial navigation system,

It is the measured value of the pseudo-range rate of the inertial navigation system. The superscript l represents the lever arm coordinate system, i represents the inertial coordinate system, e represents the geocentric ground-fixed coordinate system, j represents the number of satellites, and a represents the parameters of the satellite attributes , A is acceleration, C is coordinate transformation matrix, U is unit vector and line-of-sight unit vector.

The calculation module 530 is configured to calculate the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate.

The calculation module 530 may obtain the measurement information according to the acquired measured values of the pseudorange and pseudorange rate of the GPS navigation system and the predicted values of the pseudorange and pseudorange rate of the INS navigation system. For example, the difference between the measured value of the pseudorange of the GPS navigation system and the predicted value of the pseudorange of the INS navigation system, and the difference between the measured value of the pseudorange rate of the GPS navigation system and the predicted value of the pseudorange rate of the INS navigation system, You can get the measurement information.

The calculation module 530 includes a sampling sub-module 531 and a second calculation sub-module 532.

The sampling sub-module 531 is configured to obtain sampling data of the GPS pseudorange and pseudorange rate in the inertial navigation system sampling period according to the measured values of the GPS pseudorange and pseudorange rate and Taylor formula .

First, the sampling sub-module 531 expands the pseudorange and pseudorange rate of the GPS navigation system at the time t=kT _s using Taylor’s formula and keeps it to the second order, where T _s is the sampling period of the INS navigation system, and the GPS navigation is obtained The pseudorange and pseudorange rate of the system can be expressed by the following formula:

It’s important to note that

Is the pseudorange measurement value of the GPS navigation system,

The second calculation sub-module 532 acquires the sampling data based on the sampling data of the GPS pseudorange and the pseudorange rate and the sampling data of the inertial navigation system pseudorange and the pseudorange rate during the sampling period of the inertial navigation system. Measurement information during the period.

Indicates the measurement information of the pseudorange,

Indicates the measurement information of the pseudorange rate.

The correction module 540 is configured to eliminate the time synchronization error between the inertial navigation system and the global positioning system according to the measurement information, so as to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.

The correction module 540 includes an analysis sub-module 541 and a correction sub-module 542.

The analysis sub-module 541 is configured to linearize the measurement vector according to the measurement information and the extended Kalman filter to obtain a measurement matrix.

The measurement vector is a non-linear function about the error state vector. The analysis sub-module 541 can use the extended Kalman filter (EFK, Extended Kalman filter) to linearize it to grasp the law of sampling data change, and obtain the measurement matrix. The filter linearization formula is:

A correction sub-module 542, which obtains the time synchronization error between the global positioning system and the inertial navigation system according to the measurement matrix, and eliminates the time synchronization error to correct the global positioning system and the inertial navigation system combined positioning system Positioning.

After obtaining the time synchronization error, the correction sub-module 542 can eliminate the time synchronization error between the INS navigation system and the GPS navigation system in the sampling period, so that the GPS/INS tight integrated navigation system can accurately locate. The navigation method described in the application embodiment can reduce the amount of calculation when calculating the time synchronization error, thereby realizing the fast positioning function.

Correspondingly, an embodiment of the present application further provides an electronic device, including a processor and a memory, the memory stores a plurality of instructions, and the processor loads the instructions in the memory to perform the following steps:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

In an embodiment, the processor is configured to perform the following steps when acquiring the pseudorange and pseudorange rate measurement values of the global positioning system:

In an embodiment, when acquiring the predicted values of the pseudorange and pseudorange rate of the inertial navigation system at the same time as the global positioning system, the processor is configured to perform the following steps:

In an embodiment, when calculating the pseudorange and pseudorange rate predicted values of the inertial navigation system at the same time as the global positioning system based on the system parameters, the processor is configured to perform the following steps:

In an embodiment, when lever arm coordinate conversion is performed on the navigation solution of the inertial navigation system to obtain the first conversion value and the second conversion value, the processor is configured to perform the following steps:

among them,

Is the first converted value,

In an embodiment, when the measurement information of the combined positioning system of the global positioning system and the inertial navigation system is calculated according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate, The processor is used to execute the following steps:

The measurement information in the sampling period is acquired according to the sampling data of the global positioning system pseudorange and the pseudorange rate and the sampling data of the inertial navigation system pseudorange and the pseudorange rate within the sampling period of the inertial navigation system.

In an embodiment, the time synchronization error of the combined positioning system of the global positioning system and the inertial navigation system is eliminated according to the measurement information to correct the positioning time of the combined positioning system of the global positioning system and the inertial navigation system , The processor is configured to execute the following steps:

As shown in FIG. 7, the terminal may include a display unit 701, an input unit 702, a memory 703 including one or more computer-readable storage media, a processor 704 including one or more processing cores, a power supply 705, and Sensor 706 and other components. Those skilled in the art can understand that the structure of the electronic device shown in FIG. 7 does not constitute a limitation on the electronic device, and may include more or fewer components than shown in the figure, or a combination of certain components, or different component arrangements. among them:

The display unit 701 may be used to display information input by the user or information provided to the user and various graphical user interfaces of the terminal. These graphical user interfaces may be composed of graphics, text, icons, videos, and any combination thereof. The display unit 701 may include a display panel. Optionally, the display panel may be configured in the form of a liquid crystal display (LCD, Liquid Crystal Display), an organic light emitting diode (OLED, Organic Light-Emitting Diode), etc. Further, the touch-sensitive surface can cover the display panel. When the touch-sensitive surface detects a touch operation on or near it, it is transmitted to the processor 704 to determine the type of the touch event, and then the processor 704 displays the display panel according to the type of the touch event. Corresponding visual output is provided on the panel. Although in Fig. 7, the touch-sensitive surface and the display panel are used as two independent components to realize the input and input functions, in some embodiments, the touch-sensitive surface and the display panel can be integrated to realize the input and output functions.

The input unit 702 can be used to receive input digital or character information, and generate keyboard, mouse, joystick, optical or trackball signal input related to user settings and function control. Specifically, in a specific embodiment, the input unit 702 may include a touch-sensitive surface and other input devices. A touch-sensitive surface, also called a touch screen or a touchpad, can collect the user's touch operations on or near it (for example, the user uses any suitable objects or accessories such as fingers, stylus, etc.) on the touch-sensitive surface or on the touch-sensitive surface. Operation near the surface), and drive the corresponding connection device according to the preset program. Optionally, the touch-sensitive surface may include two parts: a touch detection device and a touch controller. Among them, the touch detection device detects the user's touch position, detects the signal brought by the touch operation, and transmits the signal to the touch controller; the touch controller receives the touch information from the touch detection device, converts it into contact coordinates, and then sends it To the processor 704, and can receive and execute the commands sent by the processor 704. In addition, multiple types such as resistive, capacitive, infrared, and surface acoustic waves can be used to realize touch-sensitive surfaces. In addition to the touch-sensitive surface, the input unit 702 may also include other input devices. Specifically, other input devices may include, but are not limited to, one or more of a physical keyboard, function keys (such as volume control buttons, switch buttons, etc.), trackball, mouse, and joystick.

The memory 703 may be used to store software programs and modules, and the processor 608 executes various functional applications and data processing by running the software programs and modules stored in the memory 703. The memory 703 may mainly include a program storage area and a data storage area. The program storage area may store an operating system, an application program required by at least one function (such as a sound playback function, an image playback function, etc.), etc.; The data (such as audio data, phone book, etc.) created by the use of the terminal, etc. In addition, the memory 703 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices. Correspondingly, the memory 703 may further include a memory controller to provide the processor 703 and the input unit 702 to access the memory 703.

The processor 704 is the control center of the terminal. It uses various interfaces and lines to connect various parts of the entire mobile phone, and executes by running or executing software programs and/or modules stored in the memory 703, and calling data stored in the memory 703. Various functions of the terminal and processing data, so as to monitor the mobile phone as a whole. Optionally, the processor 704 may include one or more processing cores; preferably, the processor 704 may integrate an application processor and a modem processor, where the application processor mainly processes the operating system, user interface, and application programs, etc. , The modem processor mainly deals with wireless communication. It can be understood that the foregoing modem processor may not be integrated into the processor 704.

The terminal also includes a power source 705 (such as a battery) for supplying power to various components. Preferably, the power source can be logically connected to the processor 704 through a power management system, so that functions such as charging, discharging, and power consumption management can be managed through the power management system. The power supply 705 may also include one or more DC or AC power supplies, a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator, and any other components.

The terminal may also include at least one sensor 706, such as a light sensor, a motion sensor, and other sensors. Specifically, the light sensor may include an ambient light sensor and a proximity sensor, where the ambient light sensor can adjust the brightness of the display panel according to the brightness of the ambient light, and the proximity sensor can turn off the display panel and/or backlight when the terminal is moved to the ear . As a kind of motion sensor, the gravity acceleration sensor can detect the magnitude of acceleration in various directions (usually three-axis), and can detect the magnitude and direction of gravity when it is stationary. It can be used to identify mobile phone posture applications (such as horizontal and vertical screen switching, related Games, magnetometer posture calibration), vibration recognition related functions (such as pedometer, percussion), etc.; as for other sensors such as gyroscopes, barometers, hygrometers, thermometers, infrared sensors, etc., which can be configured on the terminal, I will not here Repeat.

Although not shown, the terminal may also include a camera, a Bluetooth module, etc., which will not be repeated here. Specifically, in this embodiment, the processor 704 in the terminal loads the executable file corresponding to the process of one or more application programs into the memory 703 according to the following instructions, and the processor 704 runs and stores the executable file in the memory 703 Applications in 703 to achieve various functions:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the foregoing embodiments can be completed by instructions, or by instructions to control related hardware. The instructions can be stored in a computer-readable storage medium. And loaded and executed by the processor.

To this end, an embodiment of the present application provides a storage medium in which multiple instructions are stored, and the instructions can be loaded by a processor to execute the steps in any navigation method provided in the embodiments of the present application. For example, the instruction can perform the following steps:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

For the specific implementation of the above operations, please refer to the previous embodiments, which will not be repeated here.

Wherein, the storage medium may include: read only memory (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk, etc.

Since the instructions stored in the storage medium can execute the steps in any navigation method provided in the embodiments of the present application, the beneficial effects that can be achieved by any navigation method provided in the embodiments of the present application can be achieved , Please refer to the previous embodiment for details, which will not be repeated here.

The navigation method, device, electronic equipment, and storage medium provided by the embodiments of this application are described in detail above. Specific examples are used in this article to illustrate the principles and implementations of this application. The description of the above embodiments is only used To help understand the methods and core ideas of this application; at the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation and scope of application. In summary, the content of this specification It should not be construed as a limitation on this application.

Claims

A navigation method, wherein the method includes:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

Acquiring the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system;

Calculating the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate;

The time synchronization error between the inertial navigation system and the global positioning system is eliminated according to the measurement information to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.
The navigation method according to claim 1, wherein said obtaining the measured values of the pseudorange and the pseudorange rate of the global positioning system comprises:

Acquire the pseudo-range measurement value of the global positioning system according to the first preset algorithm, and obtain the pseudo-range rate measurement value of the global positioning system according to the second preset algorithm.
The navigation method according to claim 1, wherein said obtaining the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system comprises:

Acquiring the system parameters of the combined positioning system of the global positioning system and the inertial navigation system, the system parameters including the navigation solution, satellite parameters, clock offset and clock drift of the inertial navigation system;

Calculate the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system according to the system parameters.
The navigation method according to claim 3, wherein the calculation of the pseudorange and the pseudorange rate predicted value of the inertial navigation system simultaneously engraved with the global positioning system according to the system parameters comprises:

Performing lever arm coordinate conversion on the navigation solution of the inertial navigation system to obtain a first conversion value and a second conversion value;

The predicted value of the pseudorange and pseudorange rate of the inertial navigation system simultaneously engraved with the global positioning system is calculated according to the first conversion value, the second conversion value, and the unit line-of-sight distance vector of the satellite and the electronic device.
The navigation method according to claim 4, wherein the lever arm coordinate conversion is performed on the navigation solution of the inertial navigation system to obtain the first conversion value and the second conversion value, comprising:

The navigation solution of the inertial navigation system is converted by lever arm coordinates to obtain the first conversion value and the second conversion value. The conversion formula is as follows:

among them,
Is the first converted value,
Is the second conversion value, Ω is the antisymmetric matrix of the angular velocity vector, C is the coordinate conversion matrix, L is the inter-system phase center lever arm, and W is the system noise vector.
The navigation method according to claim 1, wherein said global positioning system and inertial navigation system combined positioning is calculated based on the measured values of the pseudorange and pseudorange rate and the predicted value of the pseudorange and pseudorange rate System measurement information, including:

Acquiring the sampling data of the GPS pseudorange and the pseudorange rate during the sampling period of the inertial navigation system according to the measured values of the GPS pseudorange and the pseudorange rate and the Taylor formula;

The measurement information in the sampling period is acquired according to the sampling data of the global positioning system pseudorange and the pseudorange rate and the sampling data of the inertial navigation system pseudorange and the pseudorange rate within the sampling period of the inertial navigation system.
The navigation method according to claim 6, wherein the time synchronization error of the combined positioning system of the global positioning system and the inertial navigation system is eliminated according to the measurement information to correct the global positioning system and the inertial navigation system The positioning of the combined positioning system includes:

Linearize the measurement vector according to the measurement information and the extended Kalman filter to obtain a measurement matrix;

The time synchronization error between the global positioning system and the inertial navigation system is obtained according to the measurement matrix, and the time synchronization error is eliminated to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.
A navigation device, wherein the device includes:

The first acquiring module is used to acquire the measured values of the pseudorange and pseudorange rate of the global positioning system;

The second acquiring module is used to acquire the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system simultaneously engraved with the global positioning system;

A calculation module for calculating the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate;

The correction module is used to eliminate the time synchronization error between the inertial navigation system and the global positioning system according to the measurement information, so as to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.
The navigation device according to claim 8, wherein:

The first obtaining module is specifically configured to obtain the pseudorange measurement value of the global positioning system according to a first preset algorithm, and obtain the pseudorange rate measurement value of the global positioning system according to a second preset algorithm.
The navigation device according to claim 8, wherein the second acquisition module comprises:

The acquisition sub-module is used to acquire the system parameters of the combined positioning system of the global positioning system and the inertial navigation system, the system parameters including the navigation solution of the inertial navigation system, satellite parameters, clock offset and clock drift;

The first calculation sub-module is used to calculate the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system according to the system parameters.
The navigation device according to claim 8, wherein the calculation module comprises:

A sampling sub-module for obtaining sampling data of the GPS pseudorange and pseudorange rate within the inertial navigation system sampling period according to the measured values of the GPS pseudorange and pseudorange rate and Taylor formula;

The second calculation sub-module, based on the global positioning system pseudorange and pseudorange rate sampling data and the inertial navigation system pseudorange and pseudorange rate sampling data within the inertial navigation system sampling period Measurement information within.
The navigation device according to claim 11, wherein the correction module comprises:

The analysis sub-module is used to linearize the measurement vector according to the measurement information and the extended Kalman filter to obtain a measurement matrix;

A correction sub-module, which obtains the time synchronization error between the global positioning system and the inertial navigation system according to the measurement matrix, and eliminates the time synchronization error to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system .
An electronic device includes a processor and a memory, the memory stores a plurality of instructions, wherein the processor loads the instructions in the memory to perform the following steps:

Obtain the measured values of the pseudorange and pseudorange rate of the GPS;

Acquiring the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system;

Calculating the measurement information of the combined positioning system of the global positioning system and the inertial navigation system according to the measured values of the pseudorange and the pseudorange rate and the predicted values of the pseudorange and the pseudorange rate;

The time synchronization error between the inertial navigation system and the global positioning system is eliminated according to the measurement information to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.
The electronic device according to claim 13, wherein, when acquiring the measured values of the pseudorange and the pseudorange rate of the global positioning system, the processor is configured to perform the following steps:

Acquire the pseudo-range measurement value of the global positioning system according to the first preset algorithm, and obtain the pseudo-range rate measurement value of the global positioning system according to the second preset algorithm.
The electronic device according to claim 13, wherein, when acquiring the predicted value of the pseudorange and the pseudorange rate of the inertial navigation system at the same time as the global positioning system, the processor is configured to perform the following steps:

Acquiring the system parameters of the combined positioning system of the global positioning system and the inertial navigation system, the system parameters including the navigation solution, satellite parameters, clock offset and clock drift of the inertial navigation system;

Calculate the pseudorange and the predicted value of the pseudorange rate of the inertial navigation system at the same time as the global positioning system according to the system parameters.
The electronic device according to claim 15, wherein, when calculating the pseudorange and pseudorange rate predicted values of the inertial navigation system simultaneously with the global positioning system based on the system parameters, the processor is configured to execute The following steps:

Performing lever arm coordinate conversion on the navigation solution of the inertial navigation system to obtain a first conversion value and a second conversion value;

The predicted value of the pseudorange and pseudorange rate of the inertial navigation system simultaneously engraved with the global positioning system is calculated according to the first conversion value, the second conversion value, and the unit line-of-sight distance vector of the satellite and the electronic device.
The electronic device according to claim 16, wherein, when the lever arm coordinate conversion is performed on the navigation solution of the inertial navigation system to obtain the first conversion value and the second conversion value, the processor is configured to perform the following steps:

The navigation solution of the inertial navigation system is converted by lever arm coordinates to obtain the first conversion value and the second conversion value. The conversion formula is as follows:

among them,
Is the first converted value,
Is the second conversion value, Ω is the angular velocity vector antisymmetric matrix, C is the coordinate conversion matrix, L is the phase center lever arm between systems, and W is the system noise vector.
The electronic device according to claim 13, wherein the calculation of the global positioning system and inertial navigation system combined positioning based on the measured values of the pseudorange and pseudorange rate and the predicted value of the pseudorange and pseudorange rate When measuring information of the system, the processor is used to execute the following steps:

Acquiring the sampling data of the GPS pseudorange and the pseudorange rate during the sampling period of the inertial navigation system according to the measured values of the GPS pseudorange and the pseudorange rate and the Taylor formula;

The measurement information in the sampling period is acquired according to the sampling data of the global positioning system pseudorange and the pseudorange rate and the sampling data of the inertial navigation system pseudorange and the pseudorange rate within the sampling period of the inertial navigation system.
The electronic device according to claim 18, wherein the time synchronization error of the combined positioning system of the global positioning system and the inertial navigation system is eliminated according to the measurement information to correct the global positioning system and the inertial navigation system When positioning by the combined positioning system, the processor is used to execute the following steps:

Linearize the measurement vector according to the measurement information and the extended Kalman filter to obtain a measurement matrix;

The time synchronization error between the global positioning system and the inertial navigation system is obtained according to the measurement matrix, and the time synchronization error is eliminated to correct the positioning of the combined positioning system of the global positioning system and the inertial navigation system.
A storage medium, wherein the storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor to execute the steps in the navigation method according to any one of claims 1 to 7.