阅读说明：本技术 水下动态重力数据采集半实物仿真方法及系统 (Semi-physical simulation method and system for underwater dynamic gravity data acquisition ) 是由 李姗姗 王傲明 李新星 赵东明 张金辉 单建晨 范雕 黄炎 黄志勇 于 2020-12-18 设计创作，主要内容包括：本发明属于水下潜器半实物仿真技术领域,特别涉及一种水下动态重力数据采集半实物仿真方法及系统,用于在实验室环境下模拟水下重力辅助惯性导航航迹上的重力测量数据的实时采集,包含：依据初始设定参数获取水下潜器预设航迹,并依据预设航迹确定其在每个采样点上的航迹数据；根据航迹数据通过计算角增量、速度增量和比力来模拟水下动态重力测量数据,并通过扣除有害加速度以及该点正常重力影响来获取水下采样点重力异常值；依据重力异常值及各采样点实际重力异常值的差值进行统计分析,评估半实物仿真精度。本发明能够对潜器沿水下航迹重力数据测量采集过程进行物理呈现,提供与实际测量环境相似的可靠便捷实验条件,节省人力物力财力。(The invention belongs to the technical field of underwater vehicle semi-physical simulation, and particularly relates to an underwater dynamic gravity data acquisition semi-physical simulation method and system, which are used for simulating the real-time acquisition of gravity measurement data on an underwater gravity assisted inertial navigation track in a laboratory environment and comprise the following steps: acquiring a preset track of the underwater vehicle according to initial setting parameters, and determining track data of the underwater vehicle on each sampling point according to the preset track; simulating underwater dynamic gravity measurement data by calculating angle increment, speed increment and specific force according to the flight path data, and acquiring an underwater sampling point gravity abnormal value by deducting harmful acceleration and normal gravity influence of the point; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision. The invention can physically present the measurement and acquisition process of the gravity data of the submersible vehicle along the underwater track, provides reliable and convenient experimental conditions similar to the actual measurement environment, and saves manpower, material resources and financial resources.)

1. A semi-physical simulation method for underwater dynamic gravity data acquisition is used for simulating real-time acquisition of gravity measurement data on an underwater gravity-assisted inertial navigation track in a laboratory environment, and is characterized by comprising the following contents:

acquiring a preset track of the underwater vehicle according to initial setting parameters, and determining track data of the underwater vehicle on each sampling point according to the preset track, wherein the track data comprises: position, velocity, and attitude information;

simulating underwater dynamic gravity measurement data by calculating an angle increment and a speed increment according to the track data, wherein the underwater dynamic gravity measurement data comprises an inertia angle increment, a speed increment and a specific force;

acquiring an underwater sampling point gravity abnormal value by deducting harmful acceleration and normal gravity influence at a corresponding sampling point aiming at underwater dynamic gravity measurement data; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision.

2. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 1, wherein the initial setting parameters comprise initial attitude, speed, position, motion acceleration and angular velocity of the underwater vehicle; and acquiring a preset track of the underwater vehicle by using track calculation.

3. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 1, wherein maneuvering actions are set in segments, and track data of the underwater vehicle at each sampling point is determined from a preset track according to the inertial navigation data sampling rate.

4. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 1, wherein angle increment and speed increment information is obtained by a strapdown inertial navigation algorithm for track data.

5. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 4, wherein the angular increment and the velocity increment information are obtained according to the navigation system conversion from the previous moment to the current moment, the projection of the rotation angular velocity of the navigation system relative to the inertial system under the navigation system, the equivalent rotation vector of the rotation of the coordinate system of the body, the velocity increment caused by specific force and harmful acceleration, the projection of the rotational angular velocity of the earth under the navigation system, and the projection of the navigation system relative to the angular velocity of the earth coordinate system under the navigation system.

6. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 4, characterized in that sea gravity anomaly is extended to an underwater sampling point track by considering the influence of sea water layer quality, and angle increment and speed increment information is acquired by using a strapdown inertial navigation algorithm based on the actual gravity of the sampling point; and adding gravity measurement white noise to obtain a specific force value of underwater dynamic gravity data output.

7. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 1, wherein in the simulation of the underwater dynamic gravity data, the acceleration meter and the gyroscope are sampled and output in an updating period according to the track data of the underwater vehicle at the previous moment by using a strapdown inertial navigation algorithm to obtain the previous track data at the next moment.

8. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 1, wherein a dynamic gravity measurement equation based on strapdown inertial navigation is obtained according to an underwater dynamic gravity measurement equation of a navigation system and according to a gravity vector mode invariant property.

9. The underwater dynamic gravity data acquisition semi-physical simulation method according to claim 8, wherein for underwater vehicle track data and acceleration information provided in real time by simulation, the gravity abnormal value of the underwater sampling point is obtained by deducting the influence of coriolis acceleration and motion acceleration from an underwater dynamic gravity measurement equation.

10. The utility model provides an underwater dynamic gravity data acquisition semi-physical simulation system for simulate the real-time collection of gravity measurement data on the supplementary inertial navigation flight path of gravity under water under the laboratory environment, its characterized in that contains: a presetting module, a simulation module and an evaluation module, wherein,

the presetting module is used for acquiring a preset track of the underwater vehicle according to the initial setting parameters and determining track data of the underwater vehicle on each sampling point according to the preset track, wherein the track data comprises: position, velocity, and attitude information;

the simulation module is used for simulating underwater dynamic gravity data by calculating angle increment and speed increment according to the track data, and the underwater dynamic gravity measurement data comprises inertia angle increment, speed increment and specific force;

the evaluation module is used for acquiring an abnormal gravity value of an underwater sampling point by deducting harmful acceleration and normal gravity influence at the corresponding sampling point aiming at underwater dynamic measurement gravity data; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision.

Technical Field

The invention belongs to the technical field of underwater vehicle semi-physical simulation, and particularly relates to an underwater dynamic gravity data acquisition semi-physical simulation method and system.

Background

The underwater vehicle is a movable deep diving device with underwater observation and operation capability, is mainly used for executing tasks such as underwater investigation, submarine exploration, submarine development and salvage, lifesaving and the like, and can be used as an underwater operation base for the activity of divers. With the use of underwater vehicles in coastal projects, many of the investigation and testing work can be done in a shorter time and with lower costs. The requirements of autonomy, concealment and high precision of the underwater vehicle determine that a navigation system is a combined navigation system which takes inertial navigation as a core and is assisted by other navigation systems. The gravity-assisted inertial navigation has the advantages of strong autonomy, good concealment, no limitation by regions and time domains, high positioning accuracy and the like, and is one of important means for realizing long-term safe navigation of the underwater vehicle at present. The method is limited by a plurality of conditions for implementing the underwater actual gravity-assisted inertial navigation experiment, so that repeated experimental verification and optimization of key technologies and algorithm models of the underwater actual gravity-assisted inertial navigation experiment are difficult to perform through actually acquired data.

Disclosure of Invention

Therefore, the invention provides a semi-physical simulation method and a semi-physical simulation system for underwater dynamic gravity data acquisition, which can physically present the gravity data measurement and acquisition process of a submersible vehicle along an underwater track, and provide data support which is consistent with actual track acquisition and has practical physical significance for theoretical research and model verification of underwater gravity-assisted inertial navigation in a laboratory environment.

According to the design scheme provided by the invention, the semi-physical simulation method for acquiring the underwater dynamic gravity data is used for simulating the real-time acquisition of the gravity measurement data on the underwater gravity-assisted inertial navigation track in a laboratory environment and comprises the following contents:

acquiring a preset track of the underwater vehicle according to initial setting parameters, and determining track data of the underwater vehicle on each sampling point according to the preset track, wherein the track data comprises: position, velocity, and attitude information;

simulating underwater dynamic gravity measurement data by calculating an angle increment and a speed increment according to the track data, wherein the underwater dynamic gravity measurement data comprises an inertia angle increment, a speed increment and a specific force;

acquiring an underwater sampling point gravity abnormal value by deducting harmful acceleration and normal gravity influence of the point aiming at underwater dynamic gravity measurement data; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision.

As the underwater dynamic gravity data acquisition semi-physical simulation method, further, the initial setting parameters comprise the initial attitude, the speed, the position, the motion acceleration and the angular velocity of the underwater vehicle; and acquiring a preset track of the underwater vehicle by using track calculation.

As the underwater dynamic gravity data acquisition semi-physical simulation method, the maneuvering action is set in a segmentation mode, and the flight path data of the underwater vehicle on each sampling point is determined from the preset flight path according to the sampling rate of inertial navigation data.

As the semi-physical simulation method for acquiring the underwater dynamic gravity data, angle increment and speed increment information are further obtained by a strapdown inertial navigation inversion algorithm aiming at the flight path data.

The underwater dynamic gravity data acquisition semi-physical simulation method further acquires the information of the angular increment and the speed increment according to the conversion of a navigation system from the previous moment to the current moment, the projection of the rotation angular velocity of the navigation system relative to an inertial system under the navigation system, the equivalent rotation vector of the rotation of a machine body coordinate system, the speed increment caused by specific force and harmful acceleration, the projection of the rotational angular velocity of the earth under the navigation system and the projection of the navigation system relative to the angular velocity of a terrestrial coordinate system under the navigation system.

As the semi-physical simulation method for acquiring the underwater dynamic gravity data, the influence of the quality of a seawater layer is further considered, the known actual ocean gravity anomaly is extended to the track of an underwater sampling point, and the information of the angle increment and the speed increment is acquired by utilizing a strapdown inertial navigation algorithm based on the actual gravity of the sampling point; and adding gravity measurement white noise to obtain a specific force value of underwater dynamic gravity data output.

As the semi-physical simulation method for acquiring the underwater dynamic gravity data, disclosed by the invention, further, in the simulation of the underwater dynamic gravity data, the acceleration meter and the gyroscope are sampled and output in an updating period according to the track data of the underwater vehicle at the previous moment by utilizing a strapdown inertial navigation algorithm to acquire the previous track data at the next moment.

As the underwater dynamic gravity data acquisition semi-physical simulation method, further, a dynamic gravity measurement equation based on strapdown inertial navigation is obtained according to an underwater dynamic gravity measurement equation of a navigation system and the invariant property of a gravity vector model.

As the semi-physical simulation method for acquiring the underwater dynamic gravity data, the gravity abnormal value of the underwater sampling point is further acquired by deducting the influence of Coriolis acceleration and motion acceleration from an underwater dynamic gravity measurement equation according to the track data and the acceleration information of the underwater vehicle provided in real time by simulation.

Further, based on the above method, the present invention further provides a semi-physical simulation system for acquiring underwater dynamic gravity data, which is used for simulating real-time acquisition of gravity measurement data on an underwater gravity-assisted inertial navigation track in a laboratory environment, and comprises: a presetting module, a simulation module and an evaluation module, wherein,

the presetting module is used for acquiring a preset track of the underwater vehicle according to the initial setting parameters and determining track data of the underwater vehicle on each sampling point according to the preset track, wherein the track data comprises: position, velocity, and attitude information;

the simulation module is used for simulating underwater dynamic gravity measurement data by calculating angle increment and speed increment according to the track data, and the underwater dynamic gravity measurement data comprises inertia angle increment, speed increment and specific force;

the evaluation module is used for acquiring an underwater sampling point gravity abnormal value by deducting acceleration influence aiming at the underwater dynamic gravity data; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision.

The invention has the beneficial effects that:

the invention realizes the physical presentation of the gravity data measurement and acquisition process of the submersible along the underwater track by semi-physical simulation of underwater dynamic gravity data acquisition, and can provide reliable and convenient experimental conditions similar to the actual measurement environment for the deep research of the key technology of underwater gravity-assisted inertial navigation, thereby saving a large amount of manpower, material resources and time cost, evaluating the simulation, improving the simulation effect and the accuracy and having better application prospect.

Description of the drawings:

FIG. 1 is a schematic diagram of a semi-physical simulation method for underwater dynamic gravity data acquisition in an embodiment;

FIG. 2 is a schematic diagram of a semi-physical simulation principle of underwater dynamic gravity data acquisition in an embodiment;

FIGS. 3 to 7 are schematic diagrams of flight path calculation of each sampling point in the embodiment;

FIG. 8 is a graph showing simulated specific force values of the outputs of three accelerometers of the gravimeter at a sampling point in the example;

FIG. 9 is an illustration of an embodiment of a simulated gravity anomaly;

FIG. 10 is an illustration of an actual gravity anomaly in an embodiment;

FIG. 11 is an illustration of an abnormal difference in gravity in an embodiment.

The specific implementation mode is as follows:

in order to make the objects, technical solutions and advantages of the present invention clearer and more obvious, the present invention is further described in detail below with reference to the accompanying drawings and technical solutions.

The embodiment of the invention, as shown in fig. 1, provides a semi-physical simulation method for acquiring underwater dynamic gravity data, which is used for simulating an underwater gravity assisted inertial navigation track in a laboratory environment, and comprises the following contents:

s101, acquiring a preset track of the underwater vehicle according to initial setting parameters, and determining track data of the underwater vehicle on each sampling point according to the preset track, wherein the track data comprises: position, velocity, and attitude information;

s102, simulating underwater dynamic gravity measurement data by calculating an angle increment and a speed increment according to the track data, wherein the underwater dynamic gravity measurement data comprises an inertia angle increment, a speed increment and a specific force;

s103, acquiring an underwater sampling point gravity abnormal value by deducting harmful acceleration and normal gravity influence of the point aiming at underwater dynamic gravity data; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision.

The physical presentation of the gravity data measurement and acquisition process of the submersible along the underwater track is realized by semi-physical simulation of underwater dynamic gravity data acquisition, reliable and convenient experimental conditions similar to actual measurement environment can be provided for deep research of the underwater gravity-assisted inertial navigation key technology, so that a large amount of manpower, material resources and time cost are saved, simulation is evaluated, and the simulation effect and accuracy are improved.

Furthermore, in the embodiment of the invention, the preset track of the submersible vehicle is obtained based on a track calculation method by setting the initial posture, speed, position, motion acceleration and angular speed parameters of the submersible vehicle; and determining the attitude, the speed and the position of the submersible vehicle on each sampling point from a preset track according to the inertial navigation data sampling rate.

The local horizontal coordinate system is recorded as an n system, the carrier coordinate system is recorded as a b system, and the Euler angle vector of the pitching, rolling and orientation is recorded as A ═ theta gamma psi]^TAnd the euler angular velocity vector ω ═ ω_θω_γω_ψ]^TB is the acceleration a^b＝[0a_y 0]^TAnd then, the underwater navigation motion track setting meets the following differential equation set:

wherein

Assume an initial value A (t)₀)＝[θ₀γ₀ψ₀]^T，p(t₀)＝[B₀L₀ H₀]^T，R_MRadius of curvature of meridian, R_NIs the curvature radius of the mortise-unitary ring, B is the geodetic latitude, H is the geodetic height,the attitude matrix is obtained by real-time calculation of the Euler angle at the current moment.

By setting manoeuvres, i.e. track-by-track, by sections_θ、ω_γ、ω_ψAnd a_yOne or more of the parameters are solved into flight path parameters A and v by adopting a first-order Euler method and setting step length parameters according to the inertial navigation sampling rate to solve the formula (1) time-varying differential equationⁿAnd p, completing underwater track presetting.

And (3) outputting simulation of the inertia angle increment and the speed increment, solving the information of the angle increment and the speed increment through a strapdown inertial navigation inversion algorithm principle, and simulating the measurement output of an inertia system.

Note t_mAttitude matrix of time ist_m-1N at time being t_mA conversion matrix of n series of time instantsThe projection of the navigation system at the moment relative to the rotation angular velocity of the inertial system under the navigation system ist_m-1Time t_mB is the equivalent rotation vector of the rotation at the momentTime period T ═ T_m-t_m-1The velocity increment caused by the internal specific force isTime period T ═ T_m-t_m-1The velocity increment caused by the internal detrimental acceleration isThe projection of the angular velocity of the earth at the moment under the n system isThe projection of the angular velocity of the system of time n relative to the system of e under the system of n isThe gravity value of the carrier at the position of the moment isAfter the design of the submarine track is finished, the attitude, speed and position parameters of each sampling point on the track are known, so that the attitude, speed and position parameters of each sampling point on the track are knownAndthe equivalent quantities are known or can be calculated, and from these quantities, the incremental sampling information of the inertial sensor can be solved.

First, the angle increment calculation formula is:

let an initial value Δ θ₀＝0。

The velocity increment calculation formula is:

in the formula

Let the initial value Δ v₀0. Completing the angle increment delta theta according to the formulas (2) and (3)_mAnd velocity increment Δ v_mAnd generating inertia output angle increment and speed increment.

Outputting simulation of underwater dynamic gravity measurement specific force, considering influence of sea water layer quality, and extending ocean gravity anomaly to an underwater sampling point track; substituting the actual gravity value of the sampling point into a strapdown inertial navigation inversion algorithm instead of the normal gravity value to obtain angle increment and speed increment information, and then determining specific force, wherein the specific force value can be used as underwater dynamic gravity data measurement output.

Assuming the density of the sea water layer is delta₀The quality of the sea water layer is affected

T_z＝2×2πGδ₀h (6)

Wherein G is a universal gravitation constant, and h is the diving depth of the submersible vehicle. After the influence of the sea water layer mass is deducted, an earth gravity field model (C) is utilized_nm,S_nm) And calculating the vertical gradient change of the gravity anomaly delta g, so as to extend the gravity anomaly of the sea surface downwards to the diving depth of the submersible vehicle.

Wherein M is the total mass of the earth, R represents the mean radius of the earth,is the latitude and longitude of the geocentric,representing the associated legendre function.

Calculating the normal gravity value of the sampling point according to the WGS84 normal gravity formula:

substituting the extended ocean actual gravity value into the formula (5), calculating the velocity increment by the formula (3), and differentiating the time to obtain the specific force:

note that in the formula,. DELTA.v_mThe actual gravity value is substituted into the formula (4) to obtain the gravity value. On the basis, gravity measurement white noise is added to generate an underwater dynamic gravity data output ratio value.

And (4) resolving inertial measurement data. And outputting simulation by the generated inertial measurement data, and determining the attitude, the speed and the position of the submersible vehicle according to the strapdown inertial navigation algorithm principle.

The strapdown inertial navigation updating algorithm is a recursion algorithm, namely, the attitude, the speed and the position of the submersible vehicle at the later moment are calculated according to the attitude, the speed and the position of the submersible vehicle at the previous moment and the sampling output of an accelerometer and a gyroscope in an updating period.

And (3) updating the posture, namely multiplying the posture by a matrix chain:

in the formula (I), the compound is shown in the specification,andrespectively represent t_m-1And t_mThe attitude matrix of the time of day.

The top is at_m-1,t_m]，[t_m-2,t_m-1]Sampling angular increments at equal intervals over a time period to a sum Δ θ_m-1Let T equal T_m-t_m-1Then there is Delta theta_m

(11)

Equations (10) to (13) are the strapdown inertial navigation value recursion attitude updating principle.

In the update of the speed, the speed is updated,

wherein the content of the first and second substances,andare each t_m-1And t_mThe speed of the moment. Caused by unwanted accelerationThe speed increment is calculated according to the formula (5) and the specific forceIntegral velocity deltaThe calculation formula is as follows:

in the formula,. DELTA.theta._mAnd Δ θ_m-1Respectively in the time period t_m-1,t_m]，[t_m-2,t_m-1]Incremental output of internal angle, Δ v_mAnd Δ v_m-1Respectively in the time period t_m-1,t_m]，[t_m-2,t_m-1]And outputting the inner speed increment.Is t_m-1The attitude matrix of the time of day.

And (3) position updating, namely discretizing the position differential expression of the expression (1) by adopting a trapezoidal integral method to obtain a position updating algorithm:

in the formula, M_pv(m-1/2)Linear extrapolation can be used for matrix integration M_pvCarrying out extrapolation; it is also possible to extrapolate the position variables B, H in the matrix elements and reconstruct the matrix M_pv。

And processing underwater dynamic gravity measurement data, resolving and providing the position, the attitude, the speed and the acceleration of the submersible vehicle in real time through inertial measurement data by inertial output simulation, deducting the influence of Coriolis acceleration and motion acceleration from the underwater dynamic gravity measurement data output, and generating a gravity abnormal value of an underwater sampling point.

The underwater dynamic gravity measurement vector equation under the n system is described as follows:

in the formula, gⁿIs the acceleration of gravity.A specific force output value of dynamic gravity measurement data on each sampling point;is the coriolis acceleration.

The design focuses on underwater scalar gravity measurement, and in order to avoid transmission accumulation of attitude errors, a dynamic gravity measurement equation based on strapdown inertial navigation is rewritten into the following formula according to the gravity vector model invariant principle:

in the formula (I), the compound is shown in the specification,

and carrying out statistical analysis on the difference value between the gravity abnormal value obtained after the gravity simulation generated value is subjected to data processing and the actual gravity abnormal value of each sampling point, and evaluating the simulation precision of the underwater dynamic gravity data acquisition semi-physical simulation system.

Further, based on the foregoing method, an embodiment of the present invention further provides a semi-physical simulation system for acquiring underwater dynamic gravity data, which is used for simulating real-time acquisition of gravity measurement data on an underwater gravity-assisted inertial navigation track in a laboratory environment, and includes: a presetting module, a simulation module and an evaluation module, wherein,

the presetting module is used for acquiring a preset track of the underwater vehicle according to the initial setting parameters and determining track data of the underwater vehicle on each sampling point according to the preset track, wherein the track data comprises: position, velocity, and attitude information;

the simulation module is used for simulating underwater dynamic gravity data by calculating angle increment and speed increment according to the track data, and the underwater dynamic gravity measurement data comprises inertia angle increment, speed increment and specific force;

the evaluation module is used for acquiring an abnormal gravity value of an underwater sampling point by deducting harmful acceleration and normal gravity influence at the corresponding sampling point aiming at underwater dynamic measurement gravity data; and carrying out statistical analysis according to the gravity abnormal value and the difference value of the actual gravity abnormal value of each sampling point, and evaluating the semi-physical simulation precision.

To verify the validity of the scheme, the following explanation is made in combination with simulation data:

setting underwater track parameters as follows, wherein the longitude and latitude pos0 of a track starting point is (110.9 degrees and 7.5 degrees); the diving depth is 100 m; initial attitude att0 ═ (0 ° 0 ° 0 °); initial speed v0 ═ 000 preset; the maneuvering action is at 0.0172m/s²The acceleration of the robot is uniformly accelerated for 300s, the robot moves linearly for 1h at a constant speed after the speed reaches 10 knots, then turns 90 degrees to the left, moves for 1h at a constant speed, then turns 90 degrees to the right, moves for 1h at a constant speed, and the track is finished. The whole simulation time length is 3 h. On the basis of the flight path parameter setting, the sampling rate is set to be 100HZ, and the attitude, the speed and the position of each sampling point shown in figures 3-7 are obtained, such as a flight path reduced pitch angle, a roll angle, a course angle, an estimated speed and an estimated position shown in figures 3 a-7 a respectively; and generating angle increment and speed increment of inertial output by using an inertial navigation inversion algorithm, and carrying out inertial navigation calculation under the influence of constant drift and random walk errors of a gyroscope and an accelerometer to obtain the attitude, the speed and the position of the submersible vehicle, wherein the attitude, the speed and the position are respectively calculated by error-free inertial navigation shown in figures 3b to 7b, namely the pitch angle, the roll angle, the course angle, the calculated speed and the calculated position. The attitude, speed and position of each sampling point obtained by theoretical calculation should be completely equal to those of each sampling point on the designed flight path, but are limited by model error and computer word lengthAnd if the attitude angle error is in the order of angular seconds and the speed error is less than 0.01m/s, the inertial output information obtained by simulation is considered to meet the precision requirement. The attitude, speed and position errors of each sampling point are shown in fig. 3 c-7 c as pitch angle error, roll angle error, course angle error, estimated speed error and estimated position error, and the error statistics are listed in tables 1-3.

TABLE 1 attitude error statistics

Table 2 speed error statistics table 3 position error statistics

As can be seen from tables 1 to 3, the maximum error of the attitude angle is 0.29', the maximum value of the velocity error is 0.002m/s, and the maximum value of the position error is 8.5m in the time period of the simulation time length 3 h. Because the position error of the submersible vehicle usually takes the ocean as a unit, the position error can completely meet the requirement of underwater navigation on the simulation precision of a data source in magnitude, and meanwhile, the accuracy of the information of the simulation inertial component is verified.

And (c) substituting the actual gravity value, posture, speed and position of the sampling point generated by the underwater flight path into a strapdown inertial navigation inversion algorithm, and determining output simulation specific force values of three accelerometers of the gravimeter at each sampling point, wherein (a), (b) and (c) respectively represent specific force outputs of accelerometers in x, y and z directions of the gravimeter as shown in fig. 8. After the actual measurement value-specific force of the gravimeter is obtained, the measurement data of the motor-driven steering time period of the submersible vehicle are cut off, and then the velocity, the position and the Coriolis acceleration and the motion acceleration of each sampling point obtained by inertial navigation resolving are used for correcting the gravity measurement value, so that the gravity anomaly at the point can be determined. Theoretically, the gravity outlier obtained by simulation measurement should be equal to the actual gravity outlier of each sampling point on the designed track, but due to the influence of inertial navigation simulation errors and calculation errors, the simulation measurement gravity outlier is different from the actual marine gravity outlier, the difference value is shown in fig. 9-11, the error statistics is listed in table 4, the maximum error is 0.026mGal, and the mean square error is 0.0096mGal, and the experimental result shows that the designed underwater dynamic gravity data acquisition semi-physical simulation system meets the strapdown dynamic gravity measurement principle, and can meet the simulation requirements of the laboratory underwater gravity measurement.

Table 4 gravity simulation accuracy assessment/unit: mGal

Unless specifically stated otherwise, the relative steps, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the present invention.

Based on the foregoing system, an embodiment of the present invention further provides a server, including: one or more processors; a storage device to store one or more programs that, when executed by the one or more processors, cause the one or more processors to implement the system as described above.

Based on the above system, the embodiment of the present invention further provides a computer readable medium, on which a computer program is stored, wherein the program, when executed by a processor, implements the above system.

The device provided by the embodiment of the present invention has the same implementation principle and technical effect as the system embodiment, and for the sake of brief description, reference may be made to the corresponding content in the system embodiment for the part where the device embodiment is not mentioned.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the system and the apparatus described above may refer to the corresponding processes in the foregoing system embodiments, and are not described herein again.

In all examples shown and described herein, any particular value should be construed as merely exemplary, and not as a limitation, and thus other examples of example embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus, and system may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or units through some communication interfaces, and may be in an electrical, mechanical or other form.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the system according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present invention, which are used for illustrating the technical solutions of the present invention and not for limiting the same, and the protection scope of the present invention is not limited thereto, although the present invention is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the embodiments of the present invention, and they should be construed as being included therein. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.