阅读说明：本技术 一种火星edl过程大动态导航试验验证系统及方法 (Mars EDL process large dynamic navigation test verification system and method ) 是由 徐超 黄翔宇 李茂登 胡锦昌 孙赫婕 王晓磊 赵宇 何健 张琳 周益 于 2021-09-13 设计创作，主要内容包括：一种火星EDL过程大动态导航试验验证系统及方法,属于导航技术领域。本发明试验系统采用机械转台携带IMU敏感器通过姿态映射方法模拟火星着陆器EDL过程的真实姿态运动,利用机械转台实际输出数据和IMU采集的数据可对惯性导航的关键技术及相关性能进行有效验证和评估,具有试验方法简单、易实现、可靠性高、针对性强等特点。(A big dynamic navigation test verification system and method in Mars EDL process belongs to the navigation technical field. The testing system provided by the invention adopts the mechanical turntable carrying the IMU sensor to simulate the real attitude motion of the Mars lander EDL process through an attitude mapping method, can effectively verify and evaluate the key technology and related performance of inertial navigation by utilizing the actual output data of the mechanical turntable and the data acquired by the IMU, and has the characteristics of simple testing method, easiness in realization, high reliability, strong pertinence and the like.)

1. The utility model provides a big dynamic navigation test verification system of mars EDL process which characterized in that: the system comprises a mathematical simulation computer, an IMU module and data acquisition equipment thereof, a three-axis mechanical turntable and a control computer thereof, an on-board computer and a ground computer;

the digital simulation computer is used for constructing an attitude dynamics model for simulating the attitude motion of the Mars EDL whole-process lander, calculating attitude change data of the Mars EDL whole-process lander in real time and sending the attitude change data to the mechanical turntable control computer through the data interface module;

the three-axis mechanical turntable control computer generates a three-axis mechanical turntable control instruction according to the received attitude change data of the Mars EDL process lander and sends the three-axis mechanical turntable control instruction to the three-axis mechanical turntable;

the three-axis mechanical turntable carries an IMU module and performs three-axis rotation according to a three-axis mechanical turntable control instruction; the IMU module is fixedly arranged on the three-axis mechanical rotary table, rotates along with the three-axis mechanical rotary table, measures angular velocity information, and sends the acquired angular velocity information to the satellite-borne computer and the ground computer;

the satellite-borne computer is used for carrying out inertial navigation calculation according to the angular velocity information and outputting attitude information obtained by inertial navigation calculation;

and the ground computer is used for performing navigation calculation according to the angular velocity information, converting the angular velocity information into the attitude of the IMU module relative to the geographic system, and comparing the attitude with the attitude information calculated by inertial navigation to obtain an inertial navigation attitude determination error so as to realize the experimental verification of the on-satellite inertial navigation.

2. The Mars EDL process large dynamic navigation test verification system of claim 1, wherein: the three-axis mechanical turntable control computer receives an initial attitude control mechanical turntable sent by the mathematical simulation computer through the data interface module to complete initial attitude alignment; and then the three-axis mechanical rotary table realizes the attitude tracking of the Mars EDL process by tracking the three-axis angular velocity sent by the mathematical simulation computer in real time, acquires and records the three-axis angular velocity and the attitude angle of the rotary table according to a preset sampling period by the test equipment matched with the rotary table in the attitude tracking process, and sends the acquired data to the ground computer.

3. The Mars EDL process high dynamic navigation experiment verification system of claim 2, wherein the verification system is based onAndcalculating to obtain IMU at initial t of test₀The position, speed and posture of the moment are used for finishing the initial alignment; wherein the content of the first and second substances,for testing the initial t₀The IMU measures the transformation matrix of the coordinate system relative to the inertial reference system when the rotary table is at zero position,for the IMU to measure the transformation matrix of the coordinate system relative to the IMU reference coordinate system,is a conversion matrix of the IMU reference coordinate system relative to the rotary table reference coordinate system when the rotary table is at the zero position,a transformation matrix C of a reference coordinate system of the rotary table relative to the northeast geographic system of the test site_nfAn attitude matrix from the earth's fixed system to the east-north-heaven geographic system, C_fiIs an attitude array from an inertia system to a ground fixation system, R is the geocentric distance of the test field, R is the local earth reference ellipsoid radius of the test field, h is the elevation of the test field, R is the earth reference ellipsoid radius of the test field_e、R_pSemi-major and semi-minor axes, L, of a georeferenced ellipsoid_cThe geocentric latitude of the test site.

4. The Mars EDL process large dynamic navigation test verification system of claim 1, wherein the inertial navigation solution comprises the steps of:

carrying out inertial navigation extrapolation calculation by using the received IMU module measurement data;

and converting the attitude of the IMU module relative to the inertial system and the position and the speed under the inertial system obtained by inertial navigation solution to the space northeast geographic system to complete inertial navigation solution.

5. The Mars EDL process large dynamic navigation test verification system of claim 1, wherein: the attitude dynamics model outputs three-axis angular velocity information of a Mars EDL process IMU module measuring coordinate system relative to an inertia system according to actual installation of the IMU module, the three-axis mechanical turntable control computer calculates a three-axis mechanical turntable rotating instruction according to the installation relation of the IMU module and the three-axis mechanical turntable and the three-axis angular velocity of the IMU measuring coordinate system relative to the inertia system received from the mathematical simulation computer, and drives the three-axis mechanical turntable to rotate so as to simulate movement of the Mars EDL process attitude.

6. The Mars EDL process large dynamic navigation test verification system of claim 5, wherein: in the attitude kinetic model, the attitude kinetic equation of Mars EDL process isWherein:I_Sis the moment of inertia; omega is the angular velocity of the detector relative to the inertial system; m (mum)_RIs a pneumatic moment; m (mum)_cTorque generated for the engine; m (mum)_dIs a disturbance moment; m (mum)_laIs the tension moment of the umbrella rope.

7. The Mars EDL process large dynamic navigation test verification method realized by the Mars EDL process large dynamic navigation test verification system according to claim 1, is characterized by comprising the following steps:

constructing an attitude dynamics model for simulating attitude motion of the Mars EDL whole-process lander, calculating attitude change data of the Mars EDL whole-process lander in real time, and sending the attitude change data to a mechanical turntable control computer through a data interface module;

the three-axis mechanical turntable control computer generates a three-axis mechanical turntable control instruction according to the received attitude change data of the Mars EDL process lander and sends the three-axis mechanical turntable control instruction to the three-axis mechanical turntable;

the IMU module on the three-axis mechanical turntable performs three-axis rotation according to a three-axis mechanical turntable control instruction; the IMU module is fixedly arranged on the three-axis mechanical rotary table, rotates along with the three-axis mechanical rotary table, measures angular velocity information, and sends the acquired angular velocity information to the satellite-borne computer and the ground computer;

the satellite-borne computer carries out inertial navigation resolving according to the angular velocity information and outputs attitude information resolved by the inertial navigation;

and the ground computer performs navigation calculation according to the angular velocity information, converts the angular velocity information into the attitude of the IMU module relative to the geographic system, and compares the attitude with the attitude information calculated by inertial navigation to obtain an inertial navigation attitude determination error so as to realize the experimental verification of the on-satellite inertial navigation.

8. The Mars EDL process large dynamic navigation test verification method as claimed in claim 7, wherein the three-axis mechanical turntable control computer receives an initial attitude control mechanical turntable sent by a mathematical simulation computer through a data interface module to complete initial attitude alignment; then the three-axis mechanical rotary table realizes the attitude tracking of the Mars EDL process by tracking the three-axis angular velocity sent by the mathematical simulation computer in real time, acquires and records the three-axis angular velocity and the attitude angle of the rotary table according to a preset sampling period by a test device matched with the rotary table in the attitude tracking process, and sends the acquired data to the ground computer;

according toAndcalculating to obtain IMU at initial t of test₀The position, speed and posture of the moment are used for finishing the initial alignment; wherein the content of the first and second substances,for testing the initial t₀The IMU measures the transformation matrix of the coordinate system relative to the inertial reference system when the rotary table is at zero position,for the IMU to measure the transformation matrix of the coordinate system relative to the IMU reference coordinate system,is a conversion matrix of the IMU reference coordinate system relative to the rotary table reference coordinate system when the rotary table is at the zero position,a transformation matrix C of a reference coordinate system of the rotary table relative to the northeast geographic system of the test site_nfAn attitude matrix from the earth's fixed system to the east-north-heaven geographic system, C_fiIs an attitude array from an inertia system to a ground fixation system, R is the ground center distance of the test field, R is the local earth reference ellipsoid of the test field, h is the elevation of the test field, R is the ground center distance of the test field_e、R_pSemi-major and semi-minor axes, L, of a georeferenced ellipsoid_cThe geocentric latitude of the test site;

the inertial navigation solution comprises the following steps:

carrying out inertial navigation extrapolation calculation by using the received IMU module measurement data;

converting the attitude of the IMU module relative to the inertial system and the position and the speed under the inertial system obtained by inertial navigation solution to the space northeast geographic system to complete inertial navigation solution;

the attitude dynamics model outputs three-axis angular velocity information of an IMU (inertial measurement Unit) module measurement coordinate system relative to an inertial system in a Mars EDL (electronic device development) process according to actual installation of the IMU module, the three-axis mechanical turntable control computer calculates a three-axis mechanical turntable rotation instruction according to the installation relation of the IMU module and the three-axis mechanical turntable and the three-axis angular velocity of the IMU measurement coordinate system relative to the inertial system, which is received from the mathematical simulation computer, drives the three-axis mechanical turntable to rotate, and simulates the movement of the Mars EDL process attitude;

in the attitude kinetic model, the attitude kinetic equation of Mars EDL process isWherein: i is_SIs the moment of inertia; omega is the angular velocity of the detector relative to the inertial system; m (mum)_RIs a pneumatic moment; m (mum)_cTorque generated for the engine; m (mum)_dIs a disturbance moment; m (mum)_laIs the tension moment of the umbrella rope.

9. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 7 to 8.

10. A mars EDL process high dynamic navigation experiment verification apparatus comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: the processor, when executing the computer program, performs the steps of the method according to any one of claims 7 to 8.

Technical Field

The invention relates to a system and a method for verifying a large dynamic navigation test in a Mars EDL process, and belongs to the technical field of navigation.

Background

The Entry, Landing and Landing segment (EDL) of the mars detection task is the last 6 and 7 minutes of a 7 hundred million kilometer trip of the mars detector, is a key stage of the mars surface detection task, and is the most difficult stage. The EDL technique is also one of the key techniques for the task of Mars surface probing. The method is characterized in that a Mars detector enters Mars atmosphere at the speed of 2 ten thousand kilometers per hour, a series of stages such as atmosphere deceleration, parachute dragging, power descent and the like are carried out, inertial navigation can be carried out only by using an IMU (inertial measurement Unit), no other measurement can be carried out in the whole course of attitude estimation in the inertial navigation, and once the attitude estimation error is too large, a lander is crashed, so that the performance of the inertial navigation in the Mars EDL process, particularly the accuracy of the attitude estimation, is a key factor for determining the success of a Mars soft landing task. In the former ChangE series moon soft landing process, the attitude motion of the detector is relatively stable, the interference is less, the IMU working environment is ideal, and therefore the inertial navigation performance in the moon landing process can be verified only by performing a static navigation test. Compared with a moon landing process, the dynamic state of the Mars EDL process is extremely large, especially the angular velocity of the parachuting section vibrates violently, even the gyroscope is saturated, the IMU in the whole process is interfered more, the working environment is severe, and therefore the reliability and the effectiveness of inertial navigation based on the IMU need to be verified by simulating the attitude motion of the Mars EDL large dynamic process.

Disclosure of Invention

The technical problem solved by the invention is as follows: the testing system adopts a mechanical rotary table carrying an IMU sensor to simulate the real attitude motion of the Mars lander EDL process through an attitude mapping method, can effectively verify and evaluate the key technology and related performance of inertial navigation by utilizing the actual output data of the mechanical rotary table and the data acquired by the IMU, and has the characteristics of simple testing method, easy realization, high reliability, strong pertinence and the like.

The technical solution of the invention is as follows: a Mars EDL process large dynamic navigation test verification system comprises a mathematical simulation computer, an IMU module and data acquisition equipment thereof, a three-axis mechanical turntable and a control computer thereof, an on-board computer and a ground computer;

the digital simulation computer is used for constructing an attitude dynamics model for simulating the attitude motion of the Mars EDL whole-process lander, calculating attitude change data of the Mars EDL whole-process lander in real time and sending the attitude change data to the mechanical turntable control computer through the data interface module;

the three-axis mechanical turntable control computer generates a three-axis mechanical turntable control instruction according to the received attitude change data of the Mars EDL process lander and sends the three-axis mechanical turntable control instruction to the three-axis mechanical turntable;

the three-axis mechanical turntable carries an IMU module and performs three-axis rotation according to a three-axis mechanical turntable control instruction; the IMU module is fixedly arranged on the three-axis mechanical rotary table, rotates along with the three-axis mechanical rotary table, measures angular velocity information, and sends the acquired angular velocity information to the satellite-borne computer and the ground computer;

the satellite-borne computer is used for carrying out inertial navigation calculation according to the angular velocity information and outputting attitude information obtained by inertial navigation calculation;

and the ground computer is used for performing navigation calculation according to the angular velocity information, converting the angular velocity information into the attitude of the IMU module relative to the geographic system, and comparing the attitude with the attitude information calculated by inertial navigation to obtain an inertial navigation attitude determination error so as to realize the experimental verification of the on-satellite inertial navigation.

Further, the three-axis mechanical turntable control computer receives an initial attitude control mechanical turntable sent by the mathematical simulation computer through the data interface module to complete initial attitude alignment; and then the three-axis mechanical rotary table realizes the attitude tracking of the Mars EDL process by tracking the three-axis angular velocity sent by the mathematical simulation computer in real time, acquires and records the three-axis angular velocity and the attitude angle of the rotary table according to a preset sampling period by the test equipment matched with the rotary table in the attitude tracking process, and sends the acquired data to the ground computer.

Further in accordance withAndcalculating to obtain IMU at initial t of test₀The position, speed and posture of the moment are used for finishing the initial alignment; wherein the content of the first and second substances,for testing the initial t₀The IMU measures the transformation matrix of the coordinate system relative to the inertial reference system when the rotary table is at zero position,for the IMU to measure the transformation matrix of the coordinate system relative to the IMU reference coordinate system,is a conversion matrix of the IMU reference coordinate system relative to the rotary table reference coordinate system when the rotary table is at the zero position,a transformation matrix C of a reference coordinate system of the rotary table relative to the northeast geographic system of the test site_nfAn attitude matrix from the earth's fixed system to the east-north-heaven geographic system, C_fiIs an attitude array from an inertia system to a ground fixation system, R is the geocentric distance of the test field, R is the local earth reference ellipsoid radius of the test field, h is the elevation of the test field, R is the earth reference ellipsoid radius of the test field_e、R_pSemi-major and semi-minor axes, L, of a georeferenced ellipsoid_cFor test sitesThe geocentric latitude.

Further, the inertial navigation solution comprises the following steps:

carrying out inertial navigation extrapolation calculation by using the received IMU module measurement data;

and converting the attitude of the IMU module relative to the inertial system and the position and the speed under the inertial system obtained by inertial navigation solution to the space northeast geographic system to complete inertial navigation solution.

Furthermore, the attitude dynamics model outputs three-axis angular velocity information of the Mars EDL process IMU module measurement coordinate system relative to the inertia system according to the actual installation of the IMU module, the three-axis mechanical turntable control computer calculates a three-axis mechanical turntable rotation instruction according to the installation relation of the IMU module and the three-axis mechanical turntable and the three-axis angular velocity of the IMU measurement coordinate system relative to the inertia system received from the mathematical simulation computer, and drives the three-axis mechanical turntable to rotate so as to simulate the motion of the Mars EDL process attitude.

Further, in the attitude dynamics model, the attitude dynamics equation of Mars EDL process isWherein: i is_SIs the moment of inertia; omega is the angular velocity of the detector relative to the inertial system; m (mum)_RIs a pneumatic moment; m (mum)_cTorque generated for the engine; m (mum)_dIs a disturbance moment; m (mum)_laIs the tension moment of the umbrella rope.

The Mars EDL process large dynamic navigation test verification method realized by the Mars EDL process large dynamic navigation test verification system comprises the following steps:

constructing an attitude dynamics model for simulating attitude motion of the Mars EDL whole-process lander, calculating attitude change data of the Mars EDL whole-process lander in real time, and sending the attitude change data to a mechanical turntable control computer through a data interface module;

the three-axis mechanical turntable control computer generates a three-axis mechanical turntable control instruction according to the received attitude change data of the Mars EDL process lander and sends the three-axis mechanical turntable control instruction to the three-axis mechanical turntable;

the IMU module on the three-axis mechanical turntable performs three-axis rotation according to a three-axis mechanical turntable control instruction; the IMU module is fixedly arranged on the three-axis mechanical rotary table, rotates along with the three-axis mechanical rotary table, measures angular velocity information, and sends the acquired angular velocity information to the satellite-borne computer and the ground computer;

the satellite-borne computer carries out inertial navigation resolving according to the angular velocity information and outputs attitude information resolved by the inertial navigation;

and the ground computer performs navigation calculation according to the angular velocity information, converts the angular velocity information into the attitude of the IMU module relative to the geographic system, and compares the attitude with the attitude information calculated by inertial navigation to obtain an inertial navigation attitude determination error so as to realize the experimental verification of the on-satellite inertial navigation.

Further, the three-axis mechanical turntable control computer receives an initial attitude control mechanical turntable sent by the mathematical simulation computer through the data interface module to complete initial attitude alignment; then the three-axis mechanical rotary table realizes the attitude tracking of the Mars EDL process by tracking the three-axis angular velocity sent by the mathematical simulation computer in real time, acquires and records the three-axis angular velocity and the attitude angle of the rotary table according to a preset sampling period by a test device matched with the rotary table in the attitude tracking process, and sends the acquired data to the ground computer;

according toAndcalculating to obtain IMU at initial t of test₀The position, speed and posture of the moment are used for finishing the initial alignment; wherein the content of the first and second substances,for testing the initial t₀The IMU measures the transformation matrix of the coordinate system relative to the inertial reference system when the rotary table is at zero position,measuring coordinate system phases for IMUFor the transformation matrix of the IMU reference coordinate system,is a conversion matrix of the IMU reference coordinate system relative to the rotary table reference coordinate system when the rotary table is at the zero position,a transformation matrix C of a reference coordinate system of the rotary table relative to the northeast geographic system of the test site_nfAn attitude matrix from the earth's fixed system to the east-north-heaven geographic system, C_fiIs an attitude array from an inertia system to a ground fixation system, R is the ground center distance of the test field, R is the local earth reference ellipsoid of the test field, h is the elevation of the test field, R is the ground center distance of the test field_e、R_pSemi-major and semi-minor axes, L, of a georeferenced ellipsoid_cThe geocentric latitude of the test site;

the inertial navigation solution comprises the following steps:

carrying out inertial navigation extrapolation calculation by using the received IMU module measurement data;

converting the attitude of the IMU module relative to the inertial system and the position and the speed under the inertial system obtained by inertial navigation solution to the space northeast geographic system to complete inertial navigation solution;

the attitude dynamics model outputs three-axis angular velocity information of an IMU (inertial measurement Unit) module measurement coordinate system relative to an inertial system in a Mars EDL (electronic device development) process according to actual installation of the IMU module, the three-axis mechanical turntable control computer calculates a three-axis mechanical turntable rotation instruction according to the installation relation of the IMU module and the three-axis mechanical turntable and the three-axis angular velocity of the IMU measurement coordinate system relative to the inertial system, which is received from the mathematical simulation computer, drives the three-axis mechanical turntable to rotate, and simulates the movement of the Mars EDL process attitude;

in the attitude kinetic model, the attitude kinetic equation of Mars EDL process isWherein: i is_SIs the moment of inertia; omega is the angular velocity of the detector relative to the inertial system; m (mum)_RIs a pneumatic moment; m (mum)_cFor enginesThe resulting moment; m (mum)_dIs a disturbance moment; m (mum)_laIs the tension moment of the umbrella rope.

A computer readable storage medium storing a computer program which, when executed by a processor, implements the steps of the method for verification of a mars EDL procedure large dynamic navigation test.

A Mars EDL process large dynamic navigation test verification device comprises a memory, a processor and a computer program which is stored in the memory and can run on the processor, wherein the processor executes the computer program to realize the steps of the Mars EDL process large dynamic navigation test verification method.

Compared with the prior art, the invention has the advantages that:

(1) the testing system provided by the invention can be used for acquiring the attitude angle and the angular velocity information of the Mars EDL process in real time through the mathematical closed-loop simulation system, driving the three-axis mechanical turntable carrying the IMU sensor to rotate by utilizing the attitude information to simulate the real attitude motion of the Mars lander EDL process, effectively verifying and evaluating the key technology and related performance of inertial navigation by utilizing the actual output data of the mechanical turntable and the data acquired by the IMU, and has the characteristics of simple testing method, easiness in implementation, high reliability, strong pertinence and the like.

(2) The invention designs a Mars EDL process large dynamic navigation test verification system, which realizes high-precision simulation of large-range attitude motion in complex dynamic processes of cabin pneumatic deceleration, parachute ejection, parachute descent, large bottom throwing, back cover throwing and the like in the Mars EDL process, and lays a foundation for IMU-based inertial navigation algorithm verification and performance evaluation in the Mars EDL process. (ii) a

(3) The invention designs a Mars EDL process large dynamic navigation test verification method, provides a dynamic navigation test process pose mapping method and an inertial navigation performance evaluation method, and realizes validity verification and performance evaluation of an inertial navigation algorithm.

Drawings

FIG. 1 is a schematic diagram of the composition of a Mars EDL process large dynamic navigation test verification system of the present invention.

Detailed Description

In order to better understand the technical solutions, the technical solutions of the present application are described in detail below with reference to the drawings and specific embodiments, and it should be understood that the specific features in the embodiments and examples of the present application are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application, and the technical features in the embodiments and examples of the present application may be combined with each other without conflict.

The system and the method for verifying the large dynamic navigation test in the mars EDL process provided by the embodiment of the present application are further described in detail below with reference to the drawings of the specification, and specific implementation manners may include (as shown in fig. 1 to fig. 1):

the test system consists of a mathematical simulation computer, an IMU (inertial measurement Unit) and data acquisition equipment thereof, a three-axis mechanical turntable and a control computer thereof, an on-board computer and on-board inertial navigation algorithm software, a ground computer and ground navigation performance evaluation software.

The mathematical simulation computer establishes the attitude motion of the Mars EDL whole-process lander through establishing a Mars EDL process dynamic model, a sensor measurement model, an actuating mechanism model and an on-satellite GNC algorithm, gives the attitude change of the Mars EDL whole-process lander in real time, comprises the attitude quaternion and the angular velocity of a lander body system relative to an inertial system, and sends the attitude quaternion and the angular velocity to the mechanical turntable control computer through a data interface module.

The three-axis mechanical turntable carries the IMU to rotate in three axes according to the instructions of the mechanical turntable control computer. The mechanical turntable control computer receives an initial attitude sent by the mathematical simulation computer through the data interface module to control the mechanical turntable to complete initial attitude alignment; and then the three-axis turntable tracks the postures of the Mars EDL process by tracking the three-axis angular velocity sent by the mathematical simulation computer, acquires and records the three-axis angular velocity and the posture angle of the turntable according to a preset sampling period by the supporting test equipment of the turntable in the posture tracking process, and sends the acquired data to the ground computer.

The IMU is firmly installed on the mechanical rotary table through the tool, rotates along with the three-axis rotary table, measures the rotation angular speed, and sends the collected angular speed information to the satellite-borne computer.

And the on-board computer runs the on-board inertial navigation algorithm software by using the data acquired by the IMU. And the inertial navigation algorithm software utilizes the received IMU measurement data to carry out inertial navigation extrapolation calculation. And then converting the attitude of the IMU relative to the inertial system and the position and the speed under the inertial system obtained by inertial navigation calculation into the space of the northeast geographic system, wherein the position and speed true value of the IMU relative to the geographic system is zero, so the position and speed estimated value obtained by navigation calculation is the navigation error value.

The ground computer runs ground resolving software by using data output by the mechanical rotary table, converts the rotation angle output by the rotary table into the attitude of the IMU relative to the geographic system, and can obtain inertial navigation attitude determination errors by comparing the attitude determination errors with the attitude resolved by the inertial navigation, thereby realizing the function of checking the performance of the on-satellite inertial navigation.

Mars EDL process attitude dynamics simulation method

The method comprises the steps of establishing an attitude dynamics model of a Mars EDL process lander, giving high-simulation degree simulation of Mars EDL process attitude motion, outputting three-axis angular velocity information of an IMU measurement coordinate system relative to an inertia system according to actual installation of the IMU, calculating a three-axis mechanical turntable rotation instruction by a mechanical turntable control computer according to installation relation of the IMU and the turntable and three-axis angular velocity of the IMU measurement coordinate system relative to the inertia system received from a digital simulation computer, and driving the three-axis mechanical turntable to rotate to really simulate the motion of the Mars EDL process attitude.

Pose mapping method in dynamic navigation test process

The initial attitude of the initial moment IMU measurement coordinate system of the navigation test relative to the inertial reference system can be established by defining a local fixedly-connected coordinate system and the inertial reference system and determining a conversion array of the three-axis mechanical rotary table reference coordinate system relative to the local northeast geographic coordinate system, a conversion array of the initial moment IMU reference coordinate system relative to the zero position coordinate system of the rotary table and the like through external measurement; on the other hand, the position and the initial speed of the IMU at the initial moment in the inertial system can be calculated according to the local longitude and latitude and the relation between the earth-fixed system and the inertial reference system; once the initial attitude, the initial position and the initial velocity of the IMU measurement coordinate system are established, the attitude, the position and the velocity of the IMU relative to an inertial reference system in the test process can be obtained by utilizing an on-satellite inertial navigation extrapolation algorithm according to the angular velocity and the acceleration measurement of the IMU, and the attitude, the position and the velocity of the IMU measurement coordinate system relative to a local north-east system can be obtained through the conversion relation between the inertial reference system and the local north-east geographic system, so that the attitude mapping in the dynamic navigation test process is completed

EDL process dynamic navigation performance evaluation method

The attitude of the IMU measurement coordinate system relative to the local northeast system in the dynamic navigation test process can be calculated through the mounting relation between the IMU and the mechanical rotary table at the test initial moment obtained through external measurement, the relation between the mechanical rotary table and the local northeast geographic system and the frame angle of the three-axis rotation of the rotary table. The attitude estimation performance of the satellite inertial navigation can be evaluated by comparing the attitude of the IMU measurement coordinate system obtained through the rotation angle of the turntable with the attitude of the IMU obtained through an attitude mapping method with the attitude of the local northeast system as a reference; on the other hand, the IMU at the starting time and the ending time of the test is unchanged relative to the position of the local geographical system of the northeast of the earth, and the speed is 0, so the position and speed estimated values of navigation calculation are navigation error values, and accordingly the performance evaluation of the satellite inertial navigation position estimation is completed.

In the scheme provided by the embodiment of the application, the method for verifying the large dynamic navigation test in the Mars EDL process specifically comprises the following steps:

first, dynamic navigation trial initial alignment

Defining a locally fixed coordinate systemThe z axis points to the earth rotation axis, the x axis points to the longitude meridian where the test site is located, and the y axis, the x axis and the z axis form a right-hand rectangular coordinate system which rotates along with the earth; defining an inertial coordinate systemThe earth fixing system being instantaneous with the starting time of the testThe same, it is an inertia fixed coordinate system, and does not rotate with the earth; geographical coordinate system of TiandongbeiIt rotates with the earth ball; coordinate system of the turntableReference coordinate system of rotary tableIMU reference coordinate systemWhich rotates with the turntable; measurement coordinate system formed by IMU three-axis sensitive axisWhich rotates with the turntable.

Attitude matrix C from geostationary system to the northeast-heaven geographic system_nf: obtained by rotation of the main shaft

C_nf＝C_y(-L) (1)

In the formula, C_y() For rotation about the Y-axis principal axis, L is the geographic latitude.

Attitude matrix C of inertial system to earth fixed system_fiObtained by rotation of the spindle

C_fi＝C_z(ωΔt) (2)

In the formula, C_z() Rotating around the Z-axis main shaft; omega is the rotational angular velocity of the earth; t-t ═ t₀Relative to the initial time of the experiment, t₀Time C_fiIs a unit array.

Determining a conversion matrix of a reference coordinate system of a rotary table relative to a northeast geographic system of a test field day through external field measurementAnd when the rotary table is at zero position, the IMU reference coordinate system is converted into a conversion matrix relative to the rotary table reference coordinate systemThen the initial t of the test can be calculated₀Conversion array of IMU reference coordinate system relative to the northeast geographic system of the earth when the time rotary table is at zero position

Further, the initial t of the test can be obtained₀Conversion array of IMU measurement coordinate system relative to inertial reference system at zero position of moment turntable

Then test initial t₀Attitude quaternion q of IMU measurement coordinate system relative to earth-sky northeast geographic system when time turntable is at zero position₀

Where Aq () represents the conversion function from the attitude matrix to the attitude quaternion.

The formula for calculating the center distance r of the test site is as follows

r＝R+h

Wherein h is the elevation of the test site; r_eAnd R_pThe semimajor axis and the semiminor axis of the earth reference ellipsoid.

Test initial t₀IMU at moment in inertial parameterPosition r of the system under examination_i,0And velocity v_i,0Calculated according to the following formula

r_i,0＝r[cosL_c 0 sinL_c]

v_i,0＝ω_f×r_i,0

(7)

Wherein L is_cThe geocentric latitude of the test site; omega_f＝[0 0 1]^TIs the projection of the rotation vector of the earth in the earth fixation system.

Calculating to obtain IMU at initial t of test according to the formulas (4) and (6)₀The position, velocity and attitude at the moment complete the initial alignment.

Second, Mars EDL Process attitude dynamics simulation

The Mars EDL process attitude kinetic equation is as follows:

wherein: i is_SIs the moment of inertia; omega is the angular velocity of the detector relative to the inertial system; m (mum)_RThe aerodynamic moment can be obtained by calculation according to the position, the speed and the posture of the atmosphere model and the detector; m (mum)_cThe torque generated by the engine is given according to an engine control instruction given by an on-satellite GNC algorithm and an engine model; m (mum)_dThe moment generated in the processes of polishing the outsole, polishing the back cover and the like is mainly used as the disturbance moment, and is given by a model in the processes of polishing the outsole and polishing the back cover; m (mum)_laThe tensile moment of the umbrella rope is given by an umbrella dynamics model.

The angular speed omega of the detector can be converted into the angular speed omega of the IMU measurement coordinate system relative to the inertial system according to the actual installation of the IMU_s＝C_sbω, wherein C_sbIs the mounting matrix of the IMU in the probe.

And according to the attitude dynamics model, high-precision angular velocity simulation of large-range attitude motion in complex dynamics processes such as pneumatic deceleration, parachute ejection, parachute descent, large bottom throwing, back cover throwing and the like in the Mars EDL process is given, and the high-precision angular velocity simulation is sent to a three-axis mechanical turntable control computer in real time.

Thirdly, dynamic navigation test of Mars EDL process

The three-axis mechanical turntable control computer measures the three-axis angular velocity omega of the coordinate system relative to the inertial system according to the installation relation between the IMU and the turntable and the received IMU_sCan calculate the rotating angular velocity omega of the rotary table_cIs composed of

And controlling the mechanical rotary table to rotate. The IMU collects angular velocity and acceleration information in real time in the rotation process of the mechanical turntable and sends the angular velocity and acceleration information to the satellite-borne computer, and the satellite-borne computer extrapolates the angular velocity and acceleration information according to the following formula

Wherein r, v and q are respectively IMU position, velocity and attitude quaternion of IMU measurement coordinate system relative to the inertial system under the inertial system, g is the representation of local gravity acceleration of the test site under the inertial system, a_imuAnd ω_imuThe method is used for obtaining the body acceleration and the angular velocity after IMU measurement processing according to the satellite inertial navigation algorithm.

The navigation test end t can be obtained from the equation (9)_fMoment of inertia position r_fVelocity v_fPosture q_fT is obtained according to the relation between the inertia system and the local geographical system of northeast_fPosition r under northeast geographic system of local day of time_nfVelocity v_nfPosture q_nf。

Attitude array of rotary table coordinate system relative to rotary table reference coordinate system in dynamic navigation test processFrame angle calculation capable of rotating through three axes of rotary table

WhereinC_y(θ),C_z(psi) rotation about x, y, z axes, respectivelyA rotation matrix of angles theta, psi. Then the attitude transformation matrix C from the geographical system of northeast of the heaven to the IMU measurement coordinate system is calculated by the rotation of the rotary table_snIs composed of

C_snCorresponding attitude quaternion is

q_fc＝Aq(C_sn) (13)

The attitude estimation error delta q of the satellite inertial navigation algorithm is

WhereinRepresenting a quaternion multiplication operation.

The position estimation error of the satellite inertial navigation algorithm is delta r ═ r_nfThe speed estimation error is delta v ═ v_nfAccordingly, the process of verifying the large dynamic navigation test in the Mars EDL process is completed.

Further, in the present invention,

in one possible implementation of the solution according to the invention,

in one possible implementation form of the method,

alternatively to this, the first and second parts may,

a computer-readable storage medium having stored thereon computer instructions which, when executed on a computer, cause the computer to perform the method of fig. 1.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.