Combination method, system and equipment of navigation system and computer readable storage medium

Abstract

The invention discloses a navigation system combination method, system and equipment and a computer readable storage medium, and relates to the technical field of aerospace navigation. Comprising a measurement vector, a Kalman filtering state vector, a target matrix comprising a measurement matrix, a discrete state transition matrix, a system noise matrix, a measurement noise matrix and a filtering initial covariance matrix, and a calculation matrix comprising an earth semi-major axis, correcting and converting the speed and the position of the current period under the northeast sky system according to the earth geometric parameters of the earth, the earth oblateness and the earth eccentricity to obtain a first target speed and a first target position under the transmitting system; determining a second target position and a second target speed under the transmitting system according to the current periodic position and speed under the transmitting system and the current periodic position and speed of the GPS; and determining a combined navigation result based on the first target position, the first target speed, the second target position and the second target speed. The output parameter accuracy and reliability of the integrated navigation system are improved while hardware resources are not increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aerospace navigation, in particular to a combination method, system and device of a navigation system and a computer readable storage medium. BACKGROUND

[0002] An inertial navigation system (INS) is an autonomous navigation sensor, which is not affected by external interference, can provide complete, continuous and high-frequency navigation data, has short-time high-precision characteristics, and becomes one of the main navigation systems. However, due to factors such as sensor zero drift, scale factor error, non-orthogonal installation error, etc., the INS error is continuously accumulated over time. Satellite navigation has the characteristics of wide coverage and high precision, and has long-time error stability, and becomes an auxiliary navigation device commonly used by INS. The combination scheme of INS and GPS overcomes the shortcomings of each subsystem and is superior to a single system in terms of reliability and continuity.

[0003] At present, in order to improve the reliability of the integrated navigation system, a redundant design is usually adopted, that is, the number of sensors is increased to avoid errors of the navigation system when the sensors fail. However, this method makes the integrated navigation system more complex due to the increase of equipment, and further makes the accuracy and reliability of the output parameters worse, and increases the hardware cost of the system.

[0004] Therefore, how to improve the accuracy and reliability of the output parameters of the integrated navigation system without increasing hardware resources is a current problem to be solved. SUMMARY

[0005] The present application provides a combination method, system, device and computer readable storage medium of a navigation system, which can improve the accuracy and reliability of the output parameters of the integrated navigation system without increasing hardware resources.

[0006] In a first aspect, the present application provides a combination method of a navigation system, which comprises: The velocity and position of the current period under the east-north-up system are corrected and coordinate system conversion is performed according to the measurement vector, the Kalman filter state vector, the target matrix and the earth geometric parameters, to obtain the first target velocity and the first target position corresponding to the launch system, wherein the target matrix comprises a measurement matrix, a discretized state transition matrix, a system noise matrix, a measurement noise matrix and a filter initial covariance matrix, and the earth geometric parameters comprise an earth semi-major axis, an earth flattening and an earth eccentricity; The second target position and the second target velocity corresponding to the launch system are determined according to the position and velocity of the current period under the launch system and the position and velocity of the current period of GPS, respectively; The combined navigation result is determined based on the first target position, the first target speed, the second target position and the second target speed.

[0007] In combination with the first aspect, in an implementation, before the step of correcting and converting the velocity and position of the current period in the ENU system to the first target speed and the first target position corresponding to the launch system according to the measurement vector, the Kalman filtering state vector, the target matrix and the earth geometry parameters, the method further comprises: The velocity and position of the current period in the ENU system are determined based on the earth basic parameters, the gyro increment, the accelerometer increment, the attitude quaternion, the velocity, the position, the gravitational acceleration of the last period in the ENU system and the angular velocity of the navigation system relative to the earth system, wherein the earth basic parameters comprise the earth meridian radius, the earth prime vertical radius and the earth rotation angular velocity, and the accelerometer increment is the velocity increment output by the accelerometer; The position and velocity of the current period in the launch system are determined based on the attitude change matrix, the current period velocity increment output by the inertial unit system, the position, the gravitational acceleration and the velocity of the last period in the launch system and the gravitational acceleration, the Coriolis acceleration and the related acceleration of the current period in the launch system.

[0008] In combination with the first aspect, in an implementation, the determination of the velocity and position of the current period in the ENU system based on the earth basic parameters, the gyro increment, the accelerometer increment and the attitude quaternion, the velocity, the position, the gravitational acceleration of the last period in the ENU system and the angular velocity of the navigation system relative to the earth system comprises: The first target speed increment is determined based on the gyro increment and the accelerometer increment; The projection of the first target speed increment in the ENU system is determined according to the first target speed increment and the attitude quaternion of the last period in the ENU system; The target angular velocity is determined based on the earth rotation angular velocity and the preset sampling period; The velocity of the current period in the ENU system is determined according to the projection of the first target speed increment in the ENU system, the target angular velocity and the velocity, the gravitational acceleration, the earth rotation angular velocity and the angular velocity of the navigation system relative to the earth system of the last period in the ENU system; The position of the current period in the ENU system is determined based on the earth meridian radius, the earth prime vertical radius, the preset sampling period, the velocity of the current period in the ENU system and the velocity and position of the last period in the ENU system, wherein the position comprises the latitude, the longitude and the altitude.

[0009] With reference to the first aspect, in an implementation form of the first aspect, the determining the position and the velocity in the launch frame in the current period based on the attitude change matrix, the current period velocity increment output by the inertial measurement unit, the position in the last period in the launch frame, the gravitational acceleration and the velocity in the last period in the launch frame, and the gravitational acceleration, the Coriolis acceleration and the drag acceleration in the current period in the launch frame comprises: converting the current period velocity increment output by the inertial measurement unit to the launch frame based on the attitude change matrix to obtain a second target velocity increment in the launch frame in the current period; determining the position in the launch frame in the current period according to the preset sampling period, the Coriolis acceleration, the drag acceleration and the second target velocity increment in the launch frame in the current period, and the position, the gravitational acceleration and the velocity in the last period in the launch frame; determining the velocity in the launch frame in the current period based on the preset sampling period, the velocity and the gravitational acceleration in the last period in the launch frame, and the second target velocity increment, the gravitational acceleration, the Coriolis acceleration and the drag acceleration in the current period in the launch frame.

[0010] With reference to the first aspect, in an implementation form of the first aspect, the correcting and the coordinate system conversion of the velocity and the position in the current period in the celestial north-east frame according to the measurement vector, the Kalman filtering state vector, the target matrix and the earth geometry parameters to obtain the first target velocity and the first target position corresponding to the launch frame comprises: updating the Kalman filtering state vector based on the measurement vector, the measurement matrix, the discretized state transition matrix, the system noise matrix, the measurement noise matrix and the filtering initial covariance matrix to obtain an updated state vector; feedback correcting the velocity and the position in the current period in the celestial north-east frame based on the updated state vector to obtain corrected velocity and position in the celestial north-east frame; converting the corrected velocity and position in the celestial north-east frame to the launch frame based on the earth semi-major axis, the earth flattening and the earth eccentricity to obtain the first target velocity and the first target position corresponding to the launch frame.

[0011] With reference to the first aspect, in an implementation form of the first aspect, the determining the second target position and the second target velocity corresponding to the launch frame according to the position and the velocity in the current period in the launch frame and the position and the velocity in the current period of the GPS respectively comprises: determining the position error in the launch frame based on the position in the current period in the launch frame and the position in the current period of the GPS; determining the velocity error in the launch frame based on the velocity in the current period in the launch frame and the velocity in the current period of the GPS; performing least square fitting on the position error and the velocity error respectively to obtain a position deviation and a velocity deviation; The second target position and the second target velocity corresponding to the launch system are determined according to the position deviation, the speed deviation, and the position and the speed of the current period in the launch system.

[0012] With reference to the first aspect, in an implementation form of the first aspect, the determining the integrated navigation result based on the first target position, the first target velocity, the second target position and the second target velocity comprises: determining a target position error based on the first target position and the second target position; determining a target speed error based on the first target velocity and the second target velocity; if it is detected that the target position error is not greater than a preset position error threshold and the target speed error is not greater than a preset speed error threshold, taking the first target position and the first target velocity as the integrated navigation result; if it is detected that the target position error is greater than the preset position error threshold or the target speed error is greater than the preset speed error threshold, taking the second target position and the second target velocity as the integrated navigation result.

[0013] The second aspect, the embodiments of the present application provide a kind of integrated navigation system of navigation system, the integrated navigation system of navigation system comprises: the first processing module is used to correct and coordinate system conversion according to measurement vector, Kalman filtering state vector, target matrix and earth geometry parameter to the speed and position of the current period in the East North system, obtain the first target velocity and the first target position corresponding to the launch system, the target matrix includes measurement matrix, the state transition matrix after discretization, system noise matrix, measurement noise matrix and filter initial covariance matrix, and the earth geometry parameter includes earth semi-major axis, earth flattening and earth eccentricity; the second processing module is used to determine the second target position and the second target velocity corresponding to the launch system according to the position and the speed of the current period in the launch system and the position and the speed of the current period in GPS respectively; the third processing module is used to determine the integrated navigation result based on the first target position, the first target velocity, the second target position and the second target velocity.

[0014] The third aspect, the embodiments of the present application provide an integrated navigation device of navigation system, the integrated navigation device of navigation system includes processor, memory and the integrated navigation program of navigation system stored in the memory and can be executed by the processor, wherein when the integrated navigation program of navigation system is executed by the processor, the steps of the integrated navigation method of navigation system as described in any preceding manner are implemented.

[0015] In a fourth aspect, the embodiments of the present application provide a computer readable storage medium, and the computer readable storage medium stores a combination program of a navigation system, wherein the combination program of the navigation system, when executed by a processor, implements the steps of the combination method of the navigation system according to any one of the preceding aspects.

[0016] The technical scheme provided by the embodiments of the present application has the beneficial effects of: According to the measurement vector, the Kalman filtering state vector, the target matrix including the measurement matrix, the discrete state transition matrix, the system noise matrix, the measurement noise matrix and the filtering initial covariance matrix, and the earth geometry parameter including the earth semi-major axis, the earth flattening and the earth eccentricity, the velocity and the position of the current period in the equatorial system are corrected and converted to obtain the first target velocity and the first target position corresponding to the launch system; the second target position and the second target velocity corresponding to the launch system are determined according to the position and the velocity of the current period in the launch system and the position and the velocity of the current period in the GPS respectively, and the combination navigation result is determined based on the first target position, the first target velocity, the second target position and the second target velocity. The navigation algorithms in the equatorial system and the launch system are used respectively for navigation calculation and correction in the embodiments of the present application, the first target position and the velocity in the launch system and the second target position and the velocity in the launch system are obtained, and finally the combination navigation result is obtained. No additional sensor device is needed, and the accuracy and the reliability of the output parameters of the combination navigation system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The flowchart of the combination method of the navigation system according to the embodiments of the present application is shown in the figure; Figure 2 The flowchart of the step S10 in the combination method of the navigation system according to the embodiments of the present application is shown in the figure; Figure 1 Figure 3 The function module diagram of the combination system of the navigation system according to the embodiments of the present application is shown in the figure; Figure 4 The hardware structure diagram of the combination device of the navigation system involved in the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0018] In order to enable the persons skilled in the art to better understand the present application, the technical scheme in the embodiments of the present application will be described clearly and completely 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, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the persons skilled in the art without creative labor are within the protection scope of the present application.

[0019] ​In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the embodiments of the present application with reference to the accompanying drawings.

[0020] In a first aspect, the embodiments of the present application provide a combination method of a navigation system.

[0021] In an embodiment, the combination method of the navigation system comprises the following steps. Figure 1 Figure 1 FIG. 1 is a flowchart of a combination method of a navigation system according to an embodiment of the present application. As shown in FIG. 1, the combination method of the navigation system comprises the following steps. Figure 1 Step S10: correcting and converting the velocity and position of the current period under the ENU system according to the measurement vector, the Kalman filtering state vector, the target matrix and the earth geometry parameters, to obtain the first target velocity and the first target position corresponding to the launch system, wherein the target matrix comprises a measurement matrix, a discretized state transition matrix, a system noise matrix, a measurement noise matrix and a filtering initial covariance matrix, and the earth geometry parameters comprise the semi-major axis of the earth, the flattening of the earth and the eccentricity of the earth.

[0022] In an embodiment of the present application, the ENU coordinate system is a local celestial coordinate system, which is used to describe the position and height of a ground object relative to an observer; it takes a certain point on the ground as a reference point and defines three axes: the X axis (E direction), the Y axis (N direction) and the Z axis (U direction); the measurement vector represents the observation data obtained from sensors or other measuring devices, which is used to reflect the measurement information of the current state of the target; the Kalman filtering state vector is an estimate of the system state, which includes inertial navigation errors, velocity errors, position errors, gyroscope errors and accelerometer errors; the target matrix comprises a measurement matrix, a discretized state transition matrix, a system noise matrix, a measurement noise matrix and a filtering initial covariance matrix, wherein the measurement matrix is used to describe the relationship between the measurement data and the state vector, the discretized state transition matrix is used to describe the change of the system state over time, the system noise matrix represents the uncertainty inside the system, the measurement noise matrix represents the uncertainty of the measurement error, and the filtering initial covariance matrix is used to describe the uncertainty of the initial estimate of the state; the earth geometry parameters comprise the semi-major axis of the earth, the flattening of the earth and the eccentricity of the earth, which are physical parameters describing the shape of the earth and play an important role in coordinate conversion.

[0023] It should be noted that the filtering initial covariance matrix, the system noise matrix and the measurement noise matrix need to be initialized when applied. Table 1 is the initialization of the filtering initial covariance matrix, Table 2 is the initialization of the system noise matrix, and Table 3 is the initialization of the measurement noise matrix.

[0024] Table 1 Initialization of the filtering initial covariance matrix ​​

[0025] Wherein, referring to Table 1, the diagonal line serial number is 4-6, and the corresponding value is [0.3 0.3 0.3]^2.

[0026] Table 2 initialization of system noise matrix

[0027] Wherein, referring to Table 2, the diagonal line serial number is 7-9, and the corresponding value is

[000] .

[0028] Table 3 initialization of measurement noise matrix

[0029] Wherein, referring to Table 3, the diagonal line serial number is 1-3, and the corresponding value is [0.1 0.1 0.1]^2.

[0030] It can be understood that, by means of Kalman filtering technology, the velocity and position under the northeast sky navigation system are corrected in combination with the measurement vector, the state vector and the target matrix in the embodiments of the present application; then the coordinate system conversion is performed by using the earth geometric parameters, and finally the first target velocity and the first target position corresponding to the launch system are obtained, so that the accurate target positioning and navigation information feedback correction are realized.

[0031] Step S20: determining the second target position and the second target velocity corresponding to the launch system according to the position and the velocity of the current period under the launch system and the position and the velocity of the current period under GPS respectively.

[0032] Exemplarily, in the embodiments of the present application, the error between the position of the current period under the launch system and the position of the current period under GPS and the error between the velocity of the current period under the launch system and the velocity of the current period under GPS are calculated, and then the least square method is used to fit and calculate the position error and the velocity error after fitting, and then the navigation parameters (i.e. the position and the velocity) of the current period can be effectively corrected according to the velocity error and the position error after fitting to obtain the second target position and the second target velocity corresponding to the launch system, so that the position and the velocity under the launch system are ensured to be more accurate.

[0033] Step S30: determining the combined navigation result based on the first target position, the first target velocity, the second target position and the second target velocity.

[0034] For example, in the embodiment of the present application, the comparison between the difference between the first target position and the second target position and the preset position error threshold value and the comparison between the difference between the first target speed and the second target speed and the preset speed difference threshold value can be used to evaluate which navigation algorithm can provide more accurate results. Through the comparison and determination of the results of the two algorithms, the navigation data can be effectively integrated to obtain the most accurate combined navigation result.

[0035] The present application corrects and converts the velocity and position of the current period in the equatorial system according to the measurement vector, the Kalman filter state vector, the target matrix including the measurement matrix, the discrete state transition matrix, the system noise matrix, the measurement noise matrix and the filter initial covariance matrix, and the earth geometry parameters including the earth semi-major axis, the earth flattening and the earth eccentricity, to obtain the first target velocity and the first target position corresponding to the launch system. The second target position and the second target velocity corresponding to the launch system are determined according to the position and velocity of the current period in the launch system and the position and velocity of the current period in the GPS, respectively. The combined navigation result is determined based on the first target position, the first target velocity, the second target position and the second target velocity. The present application uses the navigation algorithms in the equatorial system and the launch system to perform navigation calculation and correction, respectively, to obtain the first target position and velocity in the launch system and the second target position and velocity in the launch system, and finally obtain the combined navigation result. No additional sensor equipment is needed, and the accuracy and reliability of the output parameters of the combined navigation system are improved.

[0036] Further, in an embodiment, before the step of correcting and converting the velocity and position of the current period in the equatorial system according to the measurement vector, the Kalman filter state vector, the target matrix and the earth geometry parameters to obtain the first target velocity and the first target position corresponding to the launch system, the method further comprises: The velocity and position of the current period in the equatorial system are determined based on the earth basic parameters, the gyroscope increment, the accelerometer increment, the attitude quaternion, the velocity, the position, the gravitational acceleration of the last period in the equatorial system and the angular velocity of the navigation system relative to the earth system, wherein the earth basic parameters include the earth meridian radius, the earth equinoctial radius and the earth rotation angular velocity, and the accelerometer increment is the velocity increment output by the accelerometer; The position and velocity of the current period in the launch system are determined based on the attitude change matrix, the current period velocity increment output by the inertial measurement unit, the position, the gravitational acceleration and the velocity of the last period in the launch system, and the gravitational acceleration, the Coriolis acceleration and the related acceleration of the current period in the launch system.

[0037] Exemplarily, in the embodiment of the present application, the earth basic parameters include the earth meridian radius, the earth prime vertical radius and the earth rotation angular velocity, wherein the earth meridian radius is the equatorial radius of the earth, the earth prime vertical radius is the polar radius of the earth, and the earth rotation angular velocity refers to the speed of the earth rotation, which provides the calculation basis for the earth gravity field and the rotation effect; the gyro increment is used to describe the change of the angular velocity, which can accurately correct the attitude of the object by updating the attitude quaternion; the accelerometer increment is the velocity increment output by the accelerometer. The velocity and the position of the last period are updated in combination with the influence of the earth basic parameters, the gyro increment, the accelerometer increment, the gravity acceleration in the north-east sky system, the attitude quaternion and the earth rotation angular velocity, so as to accurately calculate the velocity and the position of the current period in the north-east sky system.

[0038] It can be understood that the gravitational acceleration is the acceleration under the action of the earth gravity, which affects the acceleration of the object; the Coriolis acceleration is the inertial force caused by the earth rotation, which affects the object moving at high speed; and the drag acceleration is the additional acceleration caused by the change of the curvature of the earth surface and the accelerated motion, all of which affect the calculation of the velocity and the position; the attitude change matrix is used to represent the change of the direction of the object in space, which reflects the current orientation by correcting the attitude quaternion of the object, thereby affecting the velocity update; the current period velocity increment output by the inertial measurement unit represents the change of the velocity relative to the last period; in combination with the influence of the attitude change matrix, the current period velocity increment, the gravitational acceleration, the Coriolis acceleration and the drag velocity on the velocity and the position of the last period in the launch system, the position and the velocity of the current period in the launch system can be accurately calculated.

[0039] Further, in an embodiment, the velocity and the position of the current period in the north-east sky system are determined based on the earth basic parameters, the gyro increment, the accelerometer increment, and the attitude quaternion, the velocity, the position, the gravity acceleration of the last period in the north-east sky system and the angular velocity of the navigation system relative to the earth system, comprising: a first target velocity increment is determined based on the gyro increment and the accelerometer increment; a projection of the first target velocity increment in the north-east sky system is determined according to the first target velocity increment and the attitude quaternion of the last period in the north-east sky system; a target angular velocity is determined based on the earth rotation angular velocity and a preset sampling period; the velocity of the current period in the north-east sky system is determined according to the projection of the first target velocity increment in the north-east sky system, the target angular velocity, and the velocity, the gravity acceleration, the earth rotation angular velocity of the last period in the north-east sky system and the angular velocity of the navigation system relative to the earth system; The position of the current period under the equatorial system is determined based on the radius of the meridian of the earth, the radius of the prime vertical of the earth, a preset sampling period, a velocity of a current period under the equatorial system, and a velocity and a position of a previous period under the equatorial system, and the position includes latitude, longitude and altitude.

[0040] Exemplarily, in the embodiment of the present application, before the position and velocity update is performed, the attitude update can be performed first, and the formula is as follows:

[0041] In the formula, is the attitude quaternion of the kth sampling period (i.e. the previous period); is the conjugate attitude quaternion of the kth sampling period; is the attitude quaternion of the k+1th sampling period (i.e. the current period); is an intermediate variable quaternion; denotes a preset sampling period, denotes a gyro increment, denotes the angular velocity of the earth rotation under the equatorial system, and the symbol denotes quaternion multiplication; it can be understood that the function denotes the quaternion q solved from the rotation vector v, and the formula is as follows: .

[0042] The gyro increment and the accelerometer increment are substituted into the following calculation formula to obtain a first target velocity increment, and the calculation formula is as follows:

[0043] In the formula, is the accelerometer increment of the X axis of the k+1th sampling period (i.e. the current period), is the accelerometer increment of the Y axis of the k+1th sampling period, is the accelerometer increment of the Y axis of the k+1th sampling period; is the gyro increment of the X axis of the k+1th sampling period, is the gyro increment of the Y axis of the k+1th sampling period, is the gyro increment of the Z axis of the k+1th sampling period; is the first target velocity increment.

[0044] The first target velocity increment and the attitude quaternion of the previous period under the equatorial system are substituted into the following calculation formula to obtain the projection of the first target velocity increment under the equatorial system, and the calculation formula is as follows:

[0045] In the formula, is the first target velocity increment; is the attitude quaternion of the previous period in the ENU system, wherein, ; is the projection of the first target velocity increment in the ENU system, wherein, is the projection of the first target velocity increment in the ENU system in the E direction (i.e., the X axis), is the projection of the first target velocity increment in the ENU system in the N direction (i.e., the Y axis), is the projection of the first target velocity increment in the ENU system in the U direction (i.e., the Z axis).

[0046] The target angular velocity is obtained by substituting the Earth rotation angular rate and the preset sampling period into the following calculation formula:

[0047] In the formula, is the Earth rotation angular rate in the kth sampling period in the ENU system; is the preset sampling period; is the target angular velocity, is the target angular velocity of the X axis, is the target angular velocity of the Y axis, is the target angular velocity of the Z axis.

[0048] The velocity in the current period in the ENU system is obtained by substituting the projection of the first target velocity increment in the ENU system, the target angular velocity, and the velocity, the gravitational acceleration, the Earth rotation angular rate in the previous period in the ENU system, and the angular rate of the navigation system relative to the Earth system in the kth sampling period in the ENU system into the following calculation formula:

[0049] In the formula, is the projection of the first target velocity increment in the ENU system; is the target angular velocity; is the velocity in the kth sampling period (i.e., the previous period) in the ENU system; is the gravitational acceleration in the kth sampling period in the ENU system; is the angular rate of the navigation system relative to the Earth system in the kth sampling period in the ENU system; is the Earth rotation angular rate in the kth sampling period in the ENU system; is the velocity in the k+1th sampling period (i.e., the current period) in the ENU system.

[0050] It should be noted that the position includes latitude, longitude and altitude, the radius of the terrestrial meridian, the latitude of the previous period of the northeast celestial system, the altitude of the previous period of the northeast celestial system, the speed of the previous period of the northeast celestial system, the speed of the current period of the northeast celestial system, the preset sampling period is substituted into the following calculation formula to obtain the latitude of the current period of the northeast celestial system, and the calculation formula is:

[0051] In the formula, the radius of the terrestrial meridian; the latitude of the previous period of the northeast celestial system; the speed of the N direction of the previous period of the northeast celestial system; the speed of the N direction of the current period of the northeast celestial system; the preset sampling period; the latitude of the current period of the northeast celestial system; the altitude of the previous period of the northeast celestial system.

[0052] The radius of the terrestrial prime vertical, the longitude of the previous period of the northeast celestial system, the speed of the previous period of the northeast celestial system, the altitude of the previous period of the northeast celestial system, the speed of the current period of the northeast celestial system, and the preset sampling period are substituted into the following calculation formula to obtain the longitude of the current period of the northeast celestial system, and the calculation formula is:

[0053] In the formula, the radius of the terrestrial prime vertical; the longitude of the previous period of the northeast celestial system; the speed of the E direction of the previous period of the northeast celestial system; the speed of the E direction of the current period of the northeast celestial system; the preset sampling period; the longitude of the current period of the northeast celestial system; the altitude of the previous period of the northeast celestial system; the latitude of the current period of the northeast celestial system.

[0054] The altitude of the previous period of the northeast celestial system, the speed of the previous period of the northeast celestial system, the speed of the current period of the northeast celestial system, and the preset sampling period are substituted into the following calculation formula to obtain the altitude of the current period of the northeast celestial system, and the calculation formula is:

[0055] In the formula, the altitude of the previous period of the northeast celestial system, the speed of the U direction of the previous period of the northeast celestial system, the speed of the U direction of the current period of the northeast celestial system; is a preset sampling period; is the altitude of the current period under the northeast celestial system.

[0056] Further, in an embodiment, the determination of the position and the velocity of the current period under the launch system based on the attitude change matrix, the current period velocity increment output by the inertial measurement unit, the position of the last period under the launch system, the gravitational acceleration and the velocity, and the gravitational acceleration, the Coriolis acceleration and the drag acceleration of the current period under the launch system, comprises: converting the current period velocity increment output by the inertial measurement unit to the launch system based on the attitude change matrix to obtain the second target velocity increment of the current period under the launch system; determining the position of the current period under the launch system according to the preset sampling period, the Coriolis acceleration, the drag acceleration and the second target velocity increment of the current period under the launch system, and the position, the gravitational acceleration and the velocity of the last period under the launch system; determining the velocity of the current period under the launch system based on the preset sampling period, the velocity and the gravitational acceleration of the last period under the launch system, and the second target velocity increment, the gravitational acceleration, the Coriolis acceleration and the drag acceleration of the current period under the launch system.

[0057] Exemplarily, in the embodiment of the present application, the attitude change quaternion under the launch system can be updated according to the angular increment output by the inertial system to obtain the updated attitude change quaternion, and the calculation formula is:

[0058]

[0059] In the formula, is the attitude change quaternion of the j+1th sampling period (i.e. after updating); is the attitude change quaternion of the jth sampling period (i.e. before updating); is the angular increment output by the inertial system in the j+1th sampling period, is the X-axis angular increment output by the inertial system in the j+1th sampling period, is the Y-axis angular increment output by the inertial system in the j+1th sampling period, is the Z-axis angular increment output by the inertial system in the j+1th sampling period; and the attitude change matrix is obtained from the updated attitude change quaternion, wherein the implementation process of obtaining the attitude change matrix from the attitude change quaternion is well known in the art, and for the sake of brevity of description, it will not be described here.

[0060] Specifically, the attitude change matrix and the current period velocity increment output by the inertial measurement unit are substituted into the following calculation formula to obtain the second target velocity increment of the current period under the launch system, and the calculation formula is:

[0061] In the formula, is the attitude change matrix of the j+1th sampling period (i.e. the current period); is the velocity increment of the current period output by the inertial navigation system of the j+1th sampling period, wherein, is the velocity increment of the X axis, is the velocity increment of the Y axis, is the velocity increment of the Z axis; is the second target velocity increment of the j+1th sampling period, is the second target velocity increment of the X axis, is the second target velocity increment of the Y axis, is the second target velocity increment of the Z axis.

[0062] Specifically, the preset sampling period, the Coriolis acceleration of the X axis in the current period in the launch system, the Coriolis acceleration of the X axis in the current period in the launch system, the second target velocity increment of the X axis in the current period, the position of the X axis in the last period in the launch system, the gravitational acceleration of the X axis in the last period in the launch system and the velocity of the X axis in the last period in the launch system are substituted into the following calculation formula to obtain the position of the X axis in the current period in the launch system, and the calculation formula is:

[0063] In the formula, is the preset sampling period; is the Coriolis acceleration of the X axis in the current period in the launch system; is the Coriolis acceleration of the X axis in the current period in the launch system; is the second target velocity increment of the X axis in the current period; is the position of the X axis in the last period in the launch system; is the gravitational acceleration of the X axis in the last period in the launch system; is the velocity of the X axis in the last period in the launch system; is the position of the X axis in the current period in the launch system.

[0064] The preset sampling period, the Coriolis acceleration of the Y axis in the current period in the launch system, the Coriolis acceleration of the Y axis in the current period in the launch system, the second target velocity increment of the Y axis in the current period, the position of the Y axis in the last period in the launch system, the gravitational acceleration of the Y axis in the last period in the launch system and the velocity of the Y axis in the last period in the launch system are substituted into the following calculation formula to obtain the position of the Y axis in the current period in the launch system, and the calculation formula is:

[0065] In the formula, is the preset sampling period; Coriolis acceleration of the current period Y axis under the launch system; Inertial acceleration of the current period Y axis under the launch system; Second target speed increment of the current period Y axis; Position of the last period Y axis under the launch system; Gravitational acceleration of the last period Y axis under the launch system; Speed of the last period Y axis under the launch system; Position of the current period Y axis under the launch system.

[0066] The preset sampling period, Coriolis acceleration of the current period Z axis under the launch system, inertial acceleration of the current period Z axis under the launch system, second target speed increment of the current period Z axis, position of the last period Z axis under the launch system, gravitational acceleration of the last period Z axis under the launch system and speed of the last period Z axis under the launch system are substituted into the following calculation formula to obtain the position of the current period Z axis under the launch system, and the calculation formula is:

[0067] In the formula, T is the preset sampling period; is the preset sampling period; Coriolis acceleration of the current period Z axis under the launch system; Inertial acceleration of the current period Z axis under the launch system; Second target speed increment of the current period Z axis; Position of the last period Z axis under the launch system; Gravitational acceleration of the last period Z axis under the launch system; Speed of the last period Z axis under the launch system; Position of the current period Z axis under the launch system.

[0068] The preset sampling period, speed of the last period X axis under the launch system, gravitational acceleration of the last period X axis under the launch system, second target speed increment of the current period X axis under the launch system, gravitational acceleration of the current period X axis under the launch system, Coriolis acceleration of the current period X axis under the launch system and inertial acceleration of the current period X axis under the launch system are substituted into the following calculation formula to obtain the speed of the current period X axis under the launch system, and the calculation formula is:

[0069] In the formula, T is the preset sampling period; is the preset sampling period; Speed of the last period X axis under the launch system; Gravitational acceleration of the last period X axis under the launch system; Second target speed increment of the current period X axis under the launch system; the Coriolis acceleration of the X-axis in the current period under the launching system; the Coriolis acceleration of the X-axis in the current period under the launching system; the Coriolis acceleration of the X-axis in the current period under the launching system; the Coriolis acceleration of the X-axis in the current period under the launching system;

[0070] the Coriolis acceleration of the X-axis in the current period under the launching system;

[0071] In the formula, T is the preset sampling period; T is the preset sampling period; is the velocity of the Y-axis in the previous period under the launching system; is the gravitational acceleration of the Y-axis in the previous period under the launching system; is the second target velocity increment of the Y-axis in the current period under the launching system; is the gravitational acceleration of the Y-axis in the current period under the launching system; is the Coriolis acceleration of the Y-axis in the current period under the launching system; is the Coriolis acceleration of the Y-axis in the current period under the launching system; is the velocity of the Y-axis in the current period under the launching system.

[0072] the Coriolis acceleration of the X-axis in the current period under the launching system;

[0073] In the formula, T is the preset sampling period; T is the preset sampling period; is the velocity of the Z-axis in the previous period under the launching system; is the gravitational acceleration of the Z-axis in the previous period under the launching system; is the second target velocity increment of the Z-axis in the current period under the launching system; is the gravitational acceleration of the Z-axis in the current period under the launching system; is the Coriolis acceleration of the Z-axis in the current period under the launching system; is the Coriolis acceleration of the Z-axis in the current period under the launching system; is the velocity of the current period in the Z axis of the launch system.

[0074] Further, in an embodiment, the step of correcting and converting the velocity and position of the current period in the ECI system according to the measurement vector, the Kalman filter state vector, the target matrix and the earth geometry parameters to obtain the first target velocity and the first target position corresponding to the launch system comprises: Figure 2 Step S101: updating the Kalman filter state vector based on the measurement vector, the measurement matrix, the discretized state transition matrix, the system noise matrix, the measurement noise matrix and the filter initial covariance matrix to obtain an updated state vector; Step S102: feeding back and correcting the velocity and position of the current period in the ECI system based on the updated state vector to obtain the corrected velocity and position in the ECI system; Step S103: converting the corrected velocity and position in the ECI system to the launch system based on the earth semi-major axis, the earth flattening and the earth eccentricity to obtain the first target velocity and the first target position corresponding to the launch system.

[0075] Exemplarily, in the embodiment of the present application, the state equation of the Kalman filter is constructed as follows:

[0076] wherein, is the state transition matrix, which is a 21x21 matrix; is the system state noise, which is a 21x1 vector; is the Kalman filter state vector.

[0077] In the embodiment of the present application, the Kalman filter state vector includes inertial navigation attitude error, velocity error, position error, gyro constant error and accelerometer constant error, which is 21-dimensional in total, and the vector order and physical meaning are shown in Table 4.

[0078] Table 4 Kalman filter state vector

[0079] The measurement vector and the measurement matrix of the Kalman filter are constructed as follows:

[0080]

[0081] wherein, is the velocity of the inertial navigation system in the ECI system; is the velocity of the satellite navigation system in the ECI system; is the position of the inertial navigation system in the ECI system; ​is the position of the satellite navigation system under the Northeast Sky System; is the measurement vector; is the 3-dimensional unit matrix; is the measurement matrix.

[0082] The Kalman filter is constructed for extrapolation processing:

[0083] wherein, is the one-step transition vector; is the discrete state transition matrix; is the Kalman filter state vector; is the filter initial covariance matrix; is the system noise matrix; is the one-step transition matrix.

[0084] The Kalman filter is updated according to the above parameters:

[0085] wherein, is the Kalman gain matrix; is the measurement noise matrix; is the updated state vector; is the observation vector.

[0086] The Kalman filter measurement update result is taken The 4th to 6th elements in the vector are velocity errors to correct the Northeast Sky navigation velocity information:

[0087] wherein, is the corrected velocity under the Northeast Sky System in the k+1 sampling period; is the velocity under the Northeast Sky System in the current period.

[0088] The Kalman filter measurement update result is taken The 7th to 9th elements in the vector are position errors to correct the Northeast Sky navigation position information:

[0089] wherein, is the corrected position under the Northeast Sky System; is the position under the Northeast Sky System in the current period; Convert the corrected velocity and position under the Northeast Sky System to the launch system. First, convert the longitude and latitude to the CGCS2000 coordinate system:

[0090] wherein, is the length of the semi-major axis of the Earth, and is a constant value of 6378137, is the flattening of the Earth, and is a constant value of 0.003352810681182, is the eccentricity of the Earth, and is a constant value of 0.0818191908426; B is the latitude, L is the longitude, and h is the altitude, which are the corrected positions; is the radius of the equinoctial circle of the Earth; and then converted from the CGCS2000 coordinate system to the launch system:

[0091] wherein, is the coordinate of the launch point in the CGCS2000 system; is the coordinate of the northeast navigation point in the CGCS2000 system; is the coordinate of the northeast navigation point in the launch system, i.e., the first target position corresponding to the launch system; is the conversion matrix from the ECEF system (Earth-Centered Earth-Fixed coordinate system) to the launch system, and its expression is as follows:

[0092] wherein, is the latitude of the launch point; is the longitude of the launch point; is the launch angle of the launch point.

[0093] The corrected velocity in the northeast system is converted to the launch system to obtain the first target velocity corresponding to the launch system, and the calculation formula is as follows:

[0094] wherein, is the corrected velocity in the northeast system; is the first target velocity corresponding to the launch system.

[0095] Further, in an embodiment, the second target position and the second target velocity corresponding to the launch system are determined according to the position and the velocity of the current period in the launch system and the position and the velocity of the current period in the GPS, comprising: determining the position error in the launch system based on the position of the current period in the launch system and the position of the current period in the GPS; determining the velocity error in the launch system based on the velocity of the current period in the launch system and the velocity of the current period in the GPS; performing least square fitting on the position error and the velocity error to obtain the position deviation and the velocity deviation, respectively; and The second target position and the second target velocity corresponding to the launching system are determined according to the position deviation, the velocity deviation, and the position and the velocity of the current period under the launching system respectively.

[0096] Exemplarily, in the embodiment of the present application, the position error under the launching system is obtained by substituting the position of the current period under the launching system and the position of the current period of the GPS into the following calculation formula:

[0097] In the formula, is the position of the current period of the GPS; is the position of the current period under the launching system; is the position error under the launching system.

[0098] The velocity error under the launching system is obtained by substituting the velocity of the current period under the launching system and the velocity of the current period of the GPS into the following calculation formula:

[0099] In the formula, is the velocity of the current period of the GPS; is the velocity of the current period under the launching system; is the velocity error under the launching system.

[0100] It can be understood that n sets of position errors and velocity errors are accumulated, and least square fitting is performed on the n sets of data; taking the X-axis data as an example, the X-axis position error is set as a function of the flight time t as the independent variable The fitting calculation is performed, and the formula is as follows:

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] In the formula, is the time corresponding to the i-th set of data; is the mean of all times; is the velocity deviation calculated by least square; is the mean of all position deviations; is a temporary time variable; is the position deviation calculated by least square; is a temporary variable of position deviation; wherein the fitting algorithm of Y axis and Z axis is the same as that of X axis, which will not be described here for the sake of simplicity of description.

[0107] Substitute the position deviation of X axis and the position of X axis in the current period under the launch system into the following calculation formula to obtain the second target position corresponding to the launch system, and the calculation formula is:

[0108] In the formula, is the position deviation of X axis; is the position of X axis in the current period under the launch system; is the second target position corresponding to the launch system; wherein the determination method of the second target position of Y axis and Z axis is the same as that of X axis, which will not be described here for the sake of simplicity of description.

[0109] Substitute the velocity deviation of X axis and the velocity of X axis in the current period under the launch system into the following calculation formula to obtain the second target velocity corresponding to the launch system, and the calculation formula is:

[0110] In the formula, is the velocity deviation of X axis; is the velocity of X axis in the current period under the launch system; is the second target velocity corresponding to the launch system; wherein the determination method of the second target velocity of Y axis and Z axis is the same as that of X axis, which will not be described here for the sake of simplicity of description.

[0111] Further, in an embodiment, the determination of the integrated navigation result based on the first target position, the first target velocity, the second target position and the second target velocity comprises: determination of a target position error based on the first target position and the second target position; determination of a target velocity error based on the first target velocity and the second target velocity; if it is detected that the target position error is not greater than a preset position error threshold and the target velocity error is not greater than a preset velocity error threshold, then the first target position and the first target velocity are taken as the integrated navigation result; if it is detected that the target position error is greater than the preset position error threshold or the target velocity error is greater than the preset velocity error threshold, then the second target position and the second target velocity are taken as the integrated navigation result.

[0112] Exemplarily, in the embodiments of the present application, since the principles of the target position error and the target velocity error on the X, Y and Z axes are the same, for the sake of simplicity of description, the first target position, the second target position, the first target velocity and the second target velocity of the X axis are taken as examples for description: The first target position of the X axis and the second target position of the X axis are substituted into the following calculation formula to obtain a target position error of the X axis, the calculation formula being:

[0113] In the formula, is the first target position of the X axis; is the second target position of the X axis; is the target position error of the X axis.

[0114] The first target speed of the X axis and the second target speed of the X axis are substituted into the following calculation formula to obtain a target speed error of the X axis, the calculation formula being:

[0115] In the formula, is the first target speed of the X axis; is the second target speed of the X axis; is the target speed error of the X axis.

[0116] It should be noted that specific values of the preset position error threshold and the preset speed error threshold can be determined according to actual requirements, which are not limited herein. For example, the preset position error threshold can be preferably 50 m, and the preset speed error threshold can be preferably 5 m / s. If it is detected that the target position error is not greater than the preset position error threshold and the target speed error is not greater than the preset speed error threshold, it is indicated that the current navigation system state is relatively stable and the measurement result is reliable, and then the first target position and the first target speed obtained by the Kalman filtering correction can be taken as the integrated navigation result. If it is detected that the target position error is greater than the preset position error threshold or the target speed error is greater than the preset speed error threshold, it is indicated that the current navigation result is affected by a large error, and then the second target position and the second target speed obtained by the least square fitting can be taken as the integrated navigation result.

[0117] In a second aspect, the embodiments of the present application further provide an integrated navigation system.

[0118] In an embodiment, the integrated navigation system comprises: Figure 3 Figure 3 is a functional module schematic diagram of the integrated navigation system embodiment of the present application. As shown in Figure 3 , the integrated navigation system comprises: ​a first processing module configured to correct and convert coordinates of the velocity and the position of a current period in the ENU system according to the measurement vector, a Kalman filtering state vector, a target matrix and earth geometry parameters, to obtain a first target velocity and a first target position corresponding to the launch system, the target matrix comprising a measurement matrix, a discretized state transition matrix, a system noise matrix, a measurement noise matrix and a filtering initial covariance matrix, and the earth geometry parameters comprising an earth semi-major axis, an earth flattening and an earth eccentricity; a second processing module configured to determine a second target position and a second target velocity corresponding to the launch system respectively according to the position and the velocity of the current period in the launch system and the position and the velocity of the current period in the GPS system; a third processing module configured to determine a combined navigation result based on the first target position, the first target velocity, the second target position and the second target velocity.

[0119] Further, in an embodiment, the first processing module is specifically configured to: determine the velocity and the position of the current period in the ENU system respectively based on earth basic parameters, gyroscopic increments, accelerometer increments and the attitude quaternion, the velocity, the position, the gravitational acceleration and the angular velocity of the navigation system relative to the earth system of the last period in the ENU system, the earth basic parameters comprising an earth meridian radius, an earth equator radius and an earth rotation angular velocity, and the accelerometer increments being velocity increments output by an accelerometer; determine the position and the velocity of the current period in the launch system respectively based on an attitude change matrix, current period velocity increments output by an inertial measurement unit, the position, the gravitational acceleration and the velocity of the last period in the launch system and the gravitational acceleration, the Coriolis acceleration and the related acceleration of the current period in the launch system.

[0120] Further, in an embodiment, the first processing module is specifically further configured to: determine a first target velocity increment based on the gyroscopic increments and the accelerometer increments; determine a projection of the first target velocity increment in the ENU system according to the first target velocity increment and the attitude quaternion of the last period in the ENU system; determine a target angular velocity based on the earth rotation angular velocity and a preset sampling period; determine the velocity of the current period in the ENU system according to the projection of the first target velocity increment in the ENU system, the target angular velocity and the velocity, the gravitational acceleration, the earth rotation angular velocity and the angular velocity of the navigation system relative to the earth system of the last period in the ENU system; determine the position of the current period in the ENU system based on the earth meridian radius, the earth equator radius, the preset sampling period, the velocity of the current period in the ENU system and the velocity and the position of the last period in the ENU system, the position comprising latitude, longitude and altitude.

[0121] Further, in an embodiment, the first processing module is specifically further configured to: convert the current period of velocity increment output by the inertial measurement unit system to the launch frame based on the attitude change matrix to obtain a second target velocity increment of the current period in the launch frame; determine the position of the current period in the launch frame according to the preset sampling period, the current period of Coriolis acceleration in the launch frame, the induced acceleration and the second target velocity increment, and the position of the last period in the launch frame, the gravitational acceleration and the velocity; determine the velocity of the current period in the launch frame based on the preset sampling period, the velocity of the last period in the launch frame and the gravitational acceleration, and the second target velocity increment, the gravitational acceleration, the Coriolis acceleration and the induced acceleration of the current period in the launch frame.

[0122] Further, in an embodiment, the first processing module is specifically further configured to: update the Kalman filter state vector based on the measurement vector, the measurement matrix, the discretized state transition matrix, the system noise matrix, the measurement noise matrix and the filter initial covariance matrix to obtain an updated state vector; feedback correct the velocity and the position of the current period in the equatorial coordinate system based on the updated state vector to obtain a corrected velocity and a corrected position in the equatorial coordinate system; convert the corrected velocity and the corrected position in the equatorial coordinate system to the launch frame based on the semi-major axis of the earth, the flattening of the earth and the eccentricity of the earth to obtain a first target velocity and a first target position corresponding to the launch frame.

[0123] Further, in an embodiment, the second processing module is specifically configured to: determine the position error in the launch frame based on the position of the current period in the launch frame and the position of the current period of GPS; determine the velocity error in the launch frame based on the velocity of the current period in the launch frame and the velocity of the current period of GPS; perform least squares fitting on the position error and the velocity error respectively to obtain a position deviation and a velocity deviation; determine a second target position and a second target velocity corresponding to the launch frame according to the position deviation, the velocity deviation, and the position and the velocity of the current period in the launch frame, respectively.

[0124] Further, in an embodiment, the third processing module is specifically configured to: determine a target position error based on the first target position and the second target position; determine a target velocity error according to the first target velocity and the second target velocity; If it is detected that the target position error is not greater than the preset position error threshold and the target speed error is not greater than the preset speed error threshold, the first target position and the first target speed are taken as the combined navigation result. If it is detected that the target position error is greater than the preset position error threshold or the target speed error is greater than the preset speed error threshold, the second target position and the second target speed are taken as the combined navigation result.

[0125] The present application corrects and converts the current period velocity and position in the equatorial system according to the measurement vector, the Kalman filter state vector, the target matrix including the measurement matrix, the discrete state transition matrix, the system noise matrix, the measurement noise matrix and the filter initial covariance matrix, and the earth geometry parameters including the earth semi-major axis, the earth flattening and the earth eccentricity, to obtain the first target velocity and the first target position corresponding to the launch system; the second target position and the second target velocity corresponding to the launch system are determined according to the current period position and velocity in the launch system and the current period position and velocity in the GPS respectively, and the combined navigation result is determined based on the first target position, the first target velocity, the second target position and the second target velocity. The present application uses the navigation algorithms in the equatorial system and the launch system respectively to perform navigation calculation and correction, obtains the first target position and velocity in the launch system and the second target position and velocity in the launch system, and finally obtains the combined navigation result, without the need to increase additional sensor equipment, and improves the accuracy and reliability of the output parameters of the combined navigation system.

[0126] The functions of each module in the combined system of the navigation system correspond to the steps in the combined method of the navigation system, and the functions and implementation processes are not repeated here.

[0127] In a third aspect, the embodiments of the present application provide a combined device of a navigation system. The combined device of the navigation system can be a personal computer (PC), a notebook computer, a server, or the like device with data processing function.

[0128] Reference Figure 4 , Figure 4 The figure is a schematic diagram of the hardware structure of the combined device of the navigation system involved in the embodiments of the present application. In the embodiments of the present application, the combined device of the navigation system can include a processor, a memory, a communication interface and a communication bus.

[0129] The communication bus can be any type, used to realize the interconnection of the processor, the memory and the communication interface.

[0130] The communication interface includes input / output (I / O) interface, physical interface and logical interface, etc. for realizing the interconnection of devices inside the combination device of the navigation system, and for realizing the interconnection of the combination device of the navigation system and other devices (e.g. other computing devices or user devices). The physical interface can be an Ethernet interface, a fiber interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.

[0131] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0132] The processor can be a general-purpose processor, which can invoke the combination program of the navigation system stored in the memory and execute the combination method of the navigation system provided by the embodiments of the present application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed by the combination program of the navigation system can refer to the embodiments of the combination method of the navigation system of the present application, which will not be repeated here.

[0133] Those skilled in the art can understand that the hardware structure shown in the above-mentioned embodiments is not a limitation of the present application, and can include more or less components than the illustrated components, or combine some components, or different component arrangements. Figure 4

[0134] In a fourth aspect, the embodiments of the present application further provide a readable storage medium.

[0135] The readable storage medium of the present application stores the combination program of the navigation system, wherein the combination program of the navigation system is executed by the processor to realize the steps of the combination method of the navigation system as described above.

[0136] The method realized by the execution of the combination program of the navigation system can refer to the embodiments of the combination method of the navigation system of the present application, which will not be repeated here.

[0137] ​The terms "comprise", "comprising", "include", "including", "have" and "having" and any variations thereof in the Specification and in the Claims are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a list of steps or elements is not necessarily limited to those listed steps or elements but can include other not-listed steps or elements. The terms "first", "second", and "third" and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances.

[0138] In the description of the present embodiments, the terms "example" and "exemplary" are used to mean serving as an example, instance, or illustration. Any embodiment or design described in this application as "example", "exemplary", or "for example" should not be construed as being superior to other embodiments or designs. Rather, use of the terms "example" and "exemplary" is merely intended to present concepts in a concrete manner.

[0139] In the description of the present embodiments, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text merely describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that there are three cases of A alone, A and B together, and B alone. In addition, in the description of the present embodiments, "multiple" means two or more than two.

[0140] In some of the processes described in the present embodiments, numerous specific details are set forth. In other instances, well-known methods have not been described in detail. In the description of the present embodiments, unless otherwise specified, the order of the operations or steps should not be construed as a mandatory order, and the operations or steps can be performed in parallel or in any order. In addition, the processes can include more or fewer operations, and the operations or steps can be combined or separated, and can be performed in sequence or in parallel.

[0141] It should be noted that the sequence numbers of the above embodiments of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments.

[0142] Those skilled in the art can clearly understand the above-mentioned embodiment method can be realized by means of software and the necessary general hardware platform, of course, can also be realized by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a plurality of instructions for making a terminal device execute the method described in each embodiment of the present application.

[0143] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for combining navigation systems, characterized in that, The method for combining the navigation system includes: Based on the measurement vector, Kalman filter state vector, target matrix, and Earth geometric parameters, the velocity and position of the current period under the northeastern sky system are corrected and the coordinate system is transformed to obtain the first target velocity and the first target position corresponding to the launch system. The target matrix includes the measurement matrix, the discretized state transition matrix, the system noise matrix, the measurement noise matrix, and the initial covariance matrix of the filter. The Earth geometric parameters include the Earth's semi-major axis, the Earth's oblateness, and the Earth's eccentricity. The position and velocity of the second target corresponding to the launch system are determined based on the position and velocity of the launch system in the current cycle and the position and velocity of the GPS in the current cycle, respectively. The combined navigation result is determined based on the position and velocity of the first target, the position and velocity of the second target, and the velocity of the second target.

2. The method for combining navigation systems as described in claim 1, characterized in that, Before the step of correcting and transforming the velocity and position of the current period under the northeastern sky system based on the measurement vector, Kalman filter state vector, target matrix, and Earth geometric parameters to obtain the first target velocity and first target position corresponding to the launching system, the method further includes: Based on the Earth's basic parameters, gyroscope increments, accelerometer increments, and the attitude quaternions, velocity, position, gravitational acceleration, and angular rate of the navigation system relative to the Earth system of the previous cycle under the northeastern celestial system, the velocity and position of the current cycle under the northeastern celestial system are determined respectively. The Earth's basic parameters include the Earth's meridian radius, the Earth's zonal radius, and the Earth's rotation angular rate. The accelerometer increment is the velocity increment output by the accelerometer. The position and velocity in the current period of the launch system are determined based on the attitude change matrix, the current period velocity increment output by the inertial navigation system, the position, gravitational acceleration and velocity in the previous period in the launch system, and the gravitational acceleration, Coriolis acceleration and entrainment acceleration in the current period in the launch system.

3. The method for combining navigation systems as described in claim 2, characterized in that, The velocity and position in the current cycle under the northeastern celestial system are determined based on Earth's fundamental parameters, gyroscope increments, accelerometer increments, and the attitude quaternions, velocity, position, gravitational acceleration, and angular rate of the navigation frame relative to the Earth system from the previous cycle under the northeastern celestial system. This includes: The first target velocity increment is determined based on the gyroscope increment and the increment of the adder. The projection of the first target velocity increment under the northeastern celestial system is determined based on the first target velocity increment and the attitude quaternion of the previous cycle under the northeastern celestial system. The target angular velocity is determined based on the Earth's rotation angular rate and a preset sampling period; The velocity of the current period under the northeastern sky system is determined based on the projection of the first target velocity increment under the northeastern sky system, the target angular velocity, the velocity of the previous period under the northeastern sky system, the gravitational acceleration, the Earth's rotation angular rate, and the angular rate of the navigation system relative to the Earth system. The position of the current cycle under the northeastern celestial system is determined based on the radius of the Earth's meridian, the radius of the Earth's zonal circle, the preset sampling period, the velocity of the current cycle under the northeastern celestial system, and the velocity and position of the previous cycle under the northeastern celestial system. The position includes latitude, longitude, and altitude.

4. The method for combining navigation systems as described in claim 2, characterized in that, The determination of the position and velocity in the current period of the launch system based on the attitude change matrix, the current period velocity increment output by the inertial navigation system, the position, gravitational acceleration and velocity in the previous period of the launch system, and the gravitational acceleration, Coriolis acceleration and entrainment acceleration in the current period of the launch system includes: Based on the attitude change matrix, the velocity increment of the current cycle output by the inertial navigation system is converted to the launch frame to obtain the second target velocity increment of the current cycle in the launch frame; The position of the current period in the launch system is determined based on the preset sampling period, the Coriolis acceleration, the entrainment acceleration, the second target velocity increment, and the position, gravitational acceleration, and velocity of the previous period in the launch system. The velocity in the current period of the launch system is determined based on the preset sampling period, the velocity and gravitational acceleration of the previous period in the launch system, and the velocity increment, gravitational acceleration, Coriolis acceleration and entrainment acceleration of the second target in the current period in the launch system.

5. The method for combining navigation systems as described in claim 1, characterized in that, The process of correcting and transforming the velocity and position of the current period under the northeastern sky system based on the measurement vector, Kalman filter state vector, target matrix, and Earth geometric parameters to obtain the first target velocity and first target position corresponding to the launch system includes: The updated state vector is obtained by updating the Kalman filter state vector based on the measurement vector, measurement matrix, discretized state transition matrix, system noise matrix, measurement noise matrix, and initial covariance matrix of the filter. Based on the updated state vector, the velocity and position of the current period under the northeastern celestial system are corrected by feedback correction to obtain the corrected velocity and position under the northeastern celestial system. Based on the Earth's semi-major axis, oblateness, and eccentricity, the corrected velocity and position of the northeastern sky system are converted to the launch system to obtain the first target velocity and first target position corresponding to the launch system.

6. The method for combining navigation systems as described in claim 1, characterized in that, The step of determining the position and velocity of the second target corresponding to the transmitting system based on the position and velocity of the current cycle under the transmitting system and the position and velocity of the current cycle under GPS includes: The position error under the transmitting system is determined based on the position under the current cycle of the transmitting system and the position under the current cycle of GPS. The velocity error in the transmission system is determined based on the velocity in the current cycle of the transmission system and the velocity in the current cycle of the GPS. The position deviation and velocity deviation are obtained by performing least-squares fitting on the position error and velocity error respectively. The position and velocity of the second target corresponding to the launch system are determined based on the position deviation, velocity deviation, and the position and velocity of the target in the current cycle under the launch system.

7. The method for combining navigation systems as described in claim 1, characterized in that, The determination of the integrated navigation result based on the first target position, the first target velocity, the second target position, and the second target velocity includes: The target position error is determined based on the first target position and the second target position. The target speed error is determined based on the first target speed and the second target speed; If the detected target position error is not greater than a preset position error threshold and the target velocity error is not greater than a preset velocity error threshold, then the first target position and the first target velocity are used as the combined navigation result. If the detected target position error is greater than a preset position error threshold or the target velocity error is greater than a preset velocity error threshold, then the second target position and the second target velocity are used as the combined navigation result.

8. A combined system for a navigation system, characterized in that, The combined system of the navigation system includes: The first processing module is used to correct and transform the velocity and position of the current period under the northeastern sky system according to the measurement vector, Kalman filter state vector, target matrix and Earth geometric parameters, so as to obtain the first target velocity and first target position corresponding to the launch system. The target matrix includes the measurement matrix, the discretized state transition matrix, the system noise matrix, the measurement noise matrix and the initial covariance matrix of the filter. The Earth geometric parameters include the Earth's semi-major axis, the Earth's oblateness and the Earth's eccentricity. The second processing module is used to determine the position and velocity of the second target corresponding to the transmitting system based on the position and velocity of the current cycle under the transmitting system and the position and velocity of the GPS in the current cycle, respectively. The third processing module is used to determine the combined navigation result based on the first target position, the first target velocity, the second target position, and the second target velocity.

9. A combined device for a navigation system, characterized in that, The navigation system assembly device includes a processor, a memory, and a navigation system assembly program stored in the memory and executable by the processor, wherein the navigation system assembly program, when executed by the processor, implements the steps of the navigation system assembly method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a navigation system assembly program, wherein when the navigation system assembly program is executed by a processor, it implements the steps of the navigation system assembly method as described in any one of claims 1 to 7.

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