Beidou inertial navigation positioning system and method

Abstract

The invention discloses a Beidou inertial navigation positioning system and method, and relates to the technical field of ocean detection, and the method comprises the following steps: respectively arranging a Beidou navigation system and an inertial navigation system in an underwater detector, and when the inertial navigation system just intervenes, recording initial positioning information and a current speed vector of the Beidou system; the underwater motion state of the detector is monitored in real time through the inertial measurement unit, positioning errors caused by water flow and the sonar effect are analyzed and corrected through the sonar detector in combination with a water flow sensor and sonar signals, when the positioning precision meets the requirement, the corrected actual position is output, and if the precision does not meet the requirement, the actual position is corrected. And if not, the positioning precision is further optimized through iterative optimization analysis. According to the invention, high-precision and stable positioning of the detector in an underwater environment is realized, the problem of signal attenuation of a traditional Beidou system in underwater application is solved, and the positioning precision and reliability of the underwater detector are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ocean exploration, in particular to a Beidou inertial navigation positioning system and method. BACKGROUND

[0002] With the continuous development of ocean exploration technology, underwater detectors are increasingly widely used in scientific research, resource exploration, military defense and other fields. Especially in deep sea exploration, seabed mineral resource exploitation, marine environment monitoring and other tasks, the accuracy and reliability of underwater positioning become key factors. Traditional underwater positioning technology faces many challenges such as complex water flow, sonar attenuation, equipment drift, etc., which has an important influence on the success of the exploration task. Therefore, how to improve the positioning accuracy of underwater detectors, especially in the deep sea environment where GPS signals cannot effectively cover, has become a technical problem to be solved. With the combination of Beidou navigation system and inertial navigation technology, new positioning schemes have gradually emerged, which can overcome the shortcomings of traditional methods and promote the development of ocean exploration technology to be more accurate and efficient.

[0003] Although the Beidou inertial navigation system combines the inertial navigation system to provide relatively stable positioning support for underwater detectors, there are still some deficiencies. The variable factors in the underwater environment, such as water flow, the influence of sound wave propagation, changes in seawater density and the attenuation effect of sonar reflection, etc., can all cause the continuous deviation of positioning accuracy. Especially in tasks with high positioning accuracy requirements, the accumulation of inertial navigation system errors often becomes a big problem. Since the inertial navigation system itself is sensitive to the accumulation of long-term deviation, after the underwater detector runs for a long time, the original positioning error may be amplified sharply, affecting the successful execution of the task. Although the traditional compensation method can correct the positioning deviation to a certain extent, it still cannot effectively realize accurate real-time positioning feedback. Therefore, there is a need to more accurately and effectively integrate various factors and optimize positioning accuracy, especially when real-time correction of dynamically changing environmental factors is required, there is still a certain technical gap. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a Beidou inertial navigation positioning system and method, which solves the problems in the above background technology.

[0005] To achieve the above purpose, the present application is realized by the following technical scheme: a Beidou inertial navigation positioning method, comprising the following steps:

[0006] S1, respectively, equip the underwater detector with a Beidou navigation system and an inertial navigation system, and start the inertial navigation system for positioning correction when the Beidou navigation system signal is attenuated to less than or equal to -20dB;

[0007] S2, when the inertial navigation system just intervenes in the positioning supplement of the underwater detector, the positioning information of the Beidou navigation system at this time is calibrated as the initial coordinates, and the current speed vector v0 is recorded, and the inertial navigation position of the underwater detector is analyzed in real time through the inertial measurement unit;

[0008] S3, the inertial navigation system is corrected through the sonar detector, the depth deviation, lateral deviation and longitudinal deviation are analyzed in real time, and the positioning deviation is evaluated after being summarized;

[0009] S4, when the positioning accuracy meets the requirements, the position vector is output, when the positioning accuracy does not meet the requirements, the flow influence analysis and sonar influence analysis are carried out;

[0010] S5, after the comprehensive optimization of S3 and S4, the positioning analysis is carried out, and the corrected positioning deviation is evaluated, and the evaluation result is that when the positioning accuracy does not meet the requirements, the iterative optimization is executed, and when the positioning accuracy meets the requirements, the position vector is output.

[0011] Preferably, S1 includes S11 and S12;

[0012] S11, the Beidou navigation system and the inertial navigation system are respectively arranged in the underwater detector, when the underwater detector is started, the initial position of the device is determined through the Beidou navigation system receiving the Beidou satellite signal, and the Beidou navigation system provides the initial positioning information for the underwater detector before diving;

[0013] S12, when the underwater detector starts to dive, the GPS signal will be gradually limited, after the Beidou navigation system signal is attenuated to less than or equal to-20dB, the underwater detector is compensated in real time through the inertial navigation system, and the motion state of the underwater detector in the underwater three-dimensional space is monitored in real time by using the inertial measurement unit arranged in the underwater detector;

[0014] The inertial measurement unit is integrated with an accelerometer, a gyroscope and a magnetometer.

[0015] Preferably, S2 includes S21 and S22;

[0016] S21, after the Beidou navigation system signal is attenuated to less than or equal to-20dB, when the inertial navigation system just intervenes in the positioning supplement of the underwater detector, the positioning information of the Beidou navigation system at this time is calibrated as the initial coordinates ins0=(x0, y0, z0), and the initial speed vector v0 is recorded according to the inertial measurement unit of the underwater detector, wherein x0, y0 and z0 respectively represent the initial longitude coordinate, the initial latitude coordinate and the initial diving depth of the underwater detector;

[0017] S22, when the underwater detector continues to move, the accelerometer, gyroscope and magnetometer integrated by the inertial measurement unit are used to obtain the acceleration components of the underwater detector in the x-axis, y-axis and z-axis directions respectively, and the acceleration vector a(t) of the underwater detector at time t is obtained by summarizing, specifically: a(t)=(a x (t), a y (t), a z (t)), wherein a x (t), a y (t), a z (t) respectively represent the acceleration components of the acceleration in the x-axis, y-axis and z-axis directions at time t;

[0018] The x-axis, y-axis and z-axis directions respectively represent the east-west flow direction of seawater, the north-south flow direction of seawater and the high-low flow direction of seawater;

[0019] S23, according to the obtained acceleration vector a(t), the velocity vector v(t) of the underwater detector at time t is calculated by time integration, specifically: In the formula, a(t) represents the acceleration vector at time t, and dt represents the time differential;

[0020] The inertial navigation system calculates the preliminary inertial navigation position vector ins(t) according to the obtained velocity vector v(t), specifically:

[0021] Preferably, S3 includes S31 and S32;

[0022] S31, the depth and surrounding obstacles of the underwater detector are monitored in real time by the sonar detector installed on the underwater detector, and the monitoring result is fed back to the inertial navigation system for positioning correction, specifically including S311, S312 and S313;

[0023] S311, the real-time water depth information so(t) at time t provided by the sonar is compared with the water depth in(t) at time t calculated by the inertial navigation system in real time, the depth offset hz(t) at time t is calculated, and the water depth information of the inertial navigation system is corrected, specifically: hz(t)=so(t)-in(t);

[0024] S312, when the positioning information error of the inertial navigation system accumulates with the running time of the underwater detector, the seawater density md is collected in real time by the densitometer installed outside the underwater detector, after dimensionless processing, the distance jl(t) between the underwater detector and the obstacle at time t is measured in real time by the sonar, In the formula, sc0 represents the sound wave propagation speed at the standard water temperature, k1 represents the constant of the influence of seawater density on the sound speed, which is obtained through experiments, md0 represents the density of seawater at the standard state, md(t) represents the seawater density at time t, and Δt represents the time interval from the emission of the sound wave to the reception.

[0025] S313, after obtaining the distance jl(t) between the underwater detector and the obstacle at time t, the dimensionless processing is compared with the distance jl(t-1) between the underwater detector and the obstacle at time t-1, and the offset distance yl(t) at time t is obtained, specifically: yl(t) = jl(t) - jl(t-1).

[0026] In combination with the real-time heading angle θ(t) of the underwater detector at time t, the lateral offset amount hx(t) and the longitudinal offset amount hy(t) of the underwater detector at time t are calculated by using the trigonometric function, specifically: hx(t) = yl(t) * cos(θ(t)), hy(t) = yl(t) * sin(θ(t)), wherein cos represents the cosine function, and sin represents the sine function.

[0027] Preferably, S32, the position information of the underwater detector is preliminarily analyzed by using the inertial navigation system, and the positioning evaluation is performed, specifically including S321 and S322.

[0028] S321, the depth offset amount hz(t), the lateral offset amount hx(t) and the longitudinal offset amount hy(t) are summarized to obtain the position offset vector py(t), that is, py = (hx, hy, hz).

[0029] Preferably, S322, the error precision modulus A is preset based on the positioning deviation error allowed in the underwater exploration navigation technology field, and the positioning deviation evaluation is performed on the obtained position offset vector py(t), and the specific evaluation scheme is as follows.

[0030] When the position offset vector py(t) ≤ error precision threshold A, the positioning accuracy meets the requirements, the normal monitoring is maintained, and the current positioning is output by using the inertial navigation system.

[0031] When the position offset vector py(t) > error precision threshold A, the positioning accuracy does not meet the requirements, and compensation optimization analysis is performed at this time.

[0032] Preferably, S4, the related instructions are executed based on the evaluation result of the positioning deviation evaluation, specifically including S41 and S42.

[0033] S41, when the positioning accuracy meets the requirements, the position offset vector py(t) obtained by the sonar assisted positioning and the preliminary inertial navigation position ins(t) obtained by the inertial navigation system are comprehensively calculated to obtain the actual output position vector scw(t) of the inertial navigation system at time t, specifically: scw(t) = ins(t) - py(t);

[0034] S42, when the preliminary accuracy evaluation does not meet the requirements, compensation optimization analysis is performed;

[0035] The compensation optimization analysis includes water flow influence analysis and sonar influence analysis;

[0036] The water flow influence analysis collects the flow velocity components l x (t), l y (t) and l z (t) of seawater in the x-axis direction, y-axis direction and z-axis direction at time t through the flow sensor installed outside the underwater detector, and after dimensionless processing, they are summarized as a seawater flow velocity three-dimensional vector, which is represented as ls(t) = (l x (t), l y (t), l z (t)), the water flow changes the speed and motion trajectory of the underwater detector, and the inertial navigation system corrects the position of the underwater detector through the seawater flow velocity three-dimensional vector ls(t) obtained, and the flow influence correction vector flo(t) at time t is obtained through formula calculation, and the correction formula is as follows: In the formula, ls(t) represents the seawater flow velocity three-dimensional vector ls at time t, γ represents the influence coefficient of the water flow on the inertial navigation error, and dt represents the time integral quantity;

[0037] The sonar influence analysis is based on the influence of the sonar signal in the seawater environment, and a sonar compensation correction formula is constructed through the inertial navigation system, and the influence coefficient and the attenuation coefficient of the sonar signal are introduced, and then the influence coefficient and the attenuation coefficient are input into the sonar compensation correction formula, and the sonar influence correction vector sxz(t) at time t is output, and the influence of the reflection intensity of the sonar on the obstacle position discrimination error is optimized, and the specific formula is as follows: In the formula, T represents the total monitoring time interval, I ech (t) represents the intensity vector of the received echo signal in the three-dimensional space under the sea at time t, w1 represents the initial influence coefficient of the sonar reflection intensity, w2 represents the attenuation coefficient of the influence of the propagation distance on the sound wave transmission, exp represents the exponential decay function, and cz represents the three-dimensional position vector of the reflecting object.

[0038] Preferably, S5 includes S51 and S52;

[0039] S51, according to the obtained position offset vector py(t), water flow influence correction vector flo(t) and sonar influence correction vector sxz(t), comprehensive summary calculation is carried out, and the comprehensive optimization correction position vector yxh(t) at t time is obtained, and the specific is: In the formula, T represents the total monitoring time interval.

[0040] Preferably, S52, according to the obtained comprehensive optimization correction position vector yxh and preset error precision modulus A, the corrected positioning deviation is evaluated, and the specific evaluation scheme is as follows:

[0041] When the comprehensive optimization correction position vector yxh(t) is greater than the error precision threshold A, the corrected positioning precision does not meet the requirements;

[0042] When the comprehensive optimization correction position vector yxh(t) is less than or equal to the error precision threshold A, the corrected positioning precision meets the requirements, and normal monitoring is maintained;

[0043] After the corrected positioning deviation is evaluated, the obtained comprehensive optimization correction position vector yxh(t) and the preliminary inertial navigation position ins(t) obtained by the inertial navigation system are comprehensively calculated, and the optimized actual position vector ycw(t) of the inertial navigation system is obtained, and the specific is: ycw(t) = ins(t)- yxh(t);

[0044] When the corrected positioning deviation evaluation is that the positioning precision does not meet the requirements, the obtained optimized actual position vector ycw(t) is iterated and evaluated by S4;

[0045] When the corrected positioning deviation evaluation is that the positioning precision meets the requirements, the optimized actual position vector ycw(t) is output by the inertial navigation system.

[0046] A Beidou inertial navigation positioning system, comprising a navigation component module, a position analysis module, a position precision evaluation module, a precision correction module and a comprehensive correction evaluation module;

[0047] The navigation component module is used for arranging a Beidou navigation system and an inertial navigation system in the underwater detector respectively, and starting the inertial navigation system to correct the positioning when the Beidou navigation system signal is attenuated to less than or equal to-20dB;

[0048] The position analysis module is used for calibrating the Beidou navigation system positioning information at this time as the initial coordinates when the inertial navigation system just intervenes in the positioning supplement of the underwater detector, recording the current velocity vector v0, and analyzing the inertial navigation position of the underwater detector in real time through the inertial measurement unit;

[0049] The position accuracy evaluation module is used for positioning correction of the inertial navigation system by the sonar detector, real-time analysis of depth deviation, lateral deviation and longitudinal deviation, and positioning deviation evaluation after summarization;

[0050] The accuracy correction module is used for outputting the position vector when the positioning accuracy meets the requirements, and performing water flow influence analysis and sonar influence analysis when the positioning accuracy does not meet the requirements.

[0051] The comprehensive correction evaluation module is used for comprehensive optimization positioning analysis and correction positioning deviation evaluation according to the position accuracy evaluation module and the accuracy correction module, and the evaluation result is that when the positioning accuracy does not meet the requirements, iteration optimization is performed, and when the positioning accuracy meets the requirements, the position vector is output.

[0052] The application provides a Beidou inertial navigation positioning system and method.

[0053] (1) In the preliminary positioning stage, the Beidou navigation system in the underwater detector receives the Beidou satellite signal and provides the initial position when the underwater detector starts. When the GPS signal gradually decays to less than -20 dB, the inertial navigation system starts to intervene to compensate for real-time positioning. At this time, the inertial measurement unit monitors the acceleration, angular velocity and other motion states of the underwater detector in the underwater three-dimensional space in real time through the cooperation of the accelerometer, gyroscope and magnetometer, to provide support for accurate positioning, and ensure that the detector can continuously correct the position even in the underwater environment where the GPS signal cannot completely cover.

[0054] (2) In the positioning correction stage, the sonar detector monitors the depth of the underwater detector and the surrounding obstacles in real time, and feeds back to the inertial navigation system for positioning correction. The real-time water depth information provided by the sonar is compared with the water depth calculated by the inertial navigation system to calculate the depth deviation hz(t), and the water depth information of the inertial navigation system is corrected. At the same time, the density meter installed outside the underwater detector collects seawater density data in real time to provide an important reference for positioning deviation correction. Based on the sonar data and the distance of the underwater obstacle, combined with the heading angle of the underwater detector, the lateral deviation hx(t) and the longitudinal deviation hy(t) are calculated through the trigonometric function, the depth deviation hz(t), the lateral deviation hx(t) and the longitudinal deviation hy(t) are summarized, the position deviation vector py(t) is obtained, and the positioning deviation is evaluated, so that the positioning error is accurately corrected. The main purpose of this stage is to optimize the positioning accuracy of the underwater detector in the complex underwater environment and minimize the influence of external interference.

[0055] (3) The method in the comprehensive optimization stage, through the combination of water flow influence correction and sonar influence correction further improves the positioning accuracy. The water flow sensor collects the flow velocity of seawater in three directions in real time, and obtains the three-dimensional vector of seawater flow velocity after dimensionless processing, and then corrects the position information of the underwater detector through the inertial navigation system. At the same time, the propagation attenuation and reflection characteristics of the sonar signal are also included in the correction process, and by comprehensively collecting the position offset vector py(t), the water flow influence correction vector flo(t) and the sonar influence correction vector sxz(t), the comprehensive optimization correction position vector yxh(t) is obtained. The positioning deviation is evaluated after correction, and the positioning result is further optimized. If the positioning accuracy still does not meet the requirements, the correction will be carried out through the iterative optimization process until the positioning accuracy reaches the predetermined standard. This comprehensive optimization process not only effectively eliminates the positioning error of the underwater detector in complex environment, but also ensures its efficient and stable operation in dynamic water area, and meets the demand of high-precision positioning. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 It is a Beidou inertial navigation positioning method step schematic diagram of the application;

[0057] Figure 2 It is a Beidou inertial navigation positioning system flow schematic diagram of the application;

[0058] Figure 3 It is a connection diagram of the running relationship of each system of the application. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0060] Embodiment 1

[0061] Please refer to Figure 1 The application provides a Beidou inertial navigation positioning method, in order to achieve the above purpose, the application is realized through the following technical scheme: comprising the following steps:

[0062] S1, the Beidou navigation system and the inertial navigation system are respectively arranged in the underwater detector, and when the Beidou navigation system signal attenuation is less than or equal to-20dB, the inertial navigation system is started to correct the positioning;

[0063] S2, when the inertial navigation system just intervenes in the positioning of the underwater detector, calibrate the positioning information of the Beidou navigation system at this time as the initial coordinates, record the current speed vector v0, and then analyze the inertial navigation position of the underwater detector in real time through the inertial measurement unit;

[0064] S3, the inertial navigation system is corrected by the sonar detector, real-time analysis of depth deviation, lateral deviation and longitudinal deviation, and the positioning deviation is evaluated after being summarized;

[0065] S4, when the positioning accuracy meets the requirements, output the position vector, when the positioning accuracy does not meet the requirements, perform flow influence analysis and sonar influence analysis;

[0066] S5, after comprehensive optimization according to S3 and S4, the positioning analysis is performed, and the positioning deviation is evaluated after correction, and the evaluation result is that when the positioning accuracy does not meet the requirements, iterative optimization is performed, and when the positioning accuracy meets the requirements, the position vector is output.

[0067] In this embodiment, the inertial navigation system is automatically started after the Beidou signal is attenuated to-20dB, effectively making up for the shortcomings of single navigation system. After taking over, the inertial navigation system will compensate in real time according to the inertial measurement unit of the underwater detector, ensuring that the underwater detector can still operate stably even in the case of GPS signal disappearance. This mechanism improves the stability and reliability of underwater positioning, and in complex underwater environment, the detector can continuously provide accurate position information, overcoming the positioning blind area of traditional method after signal attenuation. Through the auxiliary correction of the sonar detector, the system can analyze the depth deviation hz(t), lateral deviation hx(t) and longitudinal deviation hy(t) of the underwater detector in real time, so as to further optimize the positioning accuracy. Specifically, the water depth information provided by the sonar detector is compared with the water depth calculated by the inertial navigation system, and the depth deviation hz(t) is calculated to correct it. In addition, by monitoring the distance jl(t) of the obstacle and combining the heading angle θ(t) of the underwater detector, the lateral deviation hx(t) and longitudinal deviation hy(t) can be accurately calculated, and the position deviation vector py(t) is obtained by summarizing these positioning deviations. These correction methods can effectively reduce the error accumulation in the inertial navigation system, ensuring that the underwater detector can still be positioned efficiently and accurately in different water environments. The comprehensive optimization process further improves the positioning accuracy through flow influence analysis and sonar influence analysis. The flow sensor obtains the three-dimensional vector ls(t) of seawater flow rate in real time, and by correcting the influence of flow on inertial navigation error, the position information of the underwater detector can be effectively corrected. At the same time, the sonar influence correction analyzes the propagation attenuation and reflection characteristics of sound wave in water, and combines the sonar echo signal intensity I ech(t) and the impact coefficient, optimizing the error of the sonar in distinguishing the position of the obstacle. Finally, by synthesizing the position offset vector py(t), the water flow correction vector flo(t) and the sonar correction vector sxz(t), the comprehensive optimized correction position vector yxh(t) is obtained, and according to the positioning accuracy evaluation result, iterative optimization or output of the optimized actual position vector ycw(t) is performed. Compared with the traditional technology, this method has achieved significant improvement in accuracy and stability, especially in dynamic water environment, through the fine compensation and correction mechanism, the adaptability and reliability of the underwater positioning system are greatly improved, and the detector can efficiently cope with the positioning challenge in complex environment.

[0068] Embodiment 2

[0069] This embodiment is an explanation and illustration in embodiment 1, please refer to Figure 1 and Figure 3 Specifically, S1 includes S11 and S12.

[0070] S11, the Beidou navigation system and the inertial navigation system are respectively arranged in the underwater detector, when the underwater detector is started, the initial position of the device is determined by receiving the Beidou satellite signal through the Beidou navigation system, and the Beidou navigation system provides the initial positioning information for the underwater detector before diving;

[0071] S12, when the underwater detector starts to dive, the GPS signal will be gradually limited, after the Beidou navigation system signal is attenuated to less than or equal to-20dB, the underwater detector is compensated in real time by the inertial navigation system, and the motion state of the underwater detector in the three-dimensional space underwater is monitored in real time by the inertial measurement unit arranged in the underwater detector.

[0072] The inertial measurement unit is integrated with an accelerometer, a gyroscope and a magnetometer.

[0073] In this embodiment, by integrating the Beidou navigation system and the inertial navigation system in the underwater detector, the problem of GPS signal attenuation and loss in the underwater positioning process can be effectively solved. The Beidou navigation system provides accurate initial positioning information for the underwater detector, ensuring that the device can be accurately started. When the underwater detector starts to dive, the GPS signal is gradually limited, and the inertial navigation system can be intelligently switched to the inertial navigation system. When the Beidou signal is attenuated to-20dB, the inertial navigation system monitors the three-dimensional motion state of the underwater detector in real time through the accelerometer, gyroscope and magnetometer of the inertial measurement unit, ensuring the continuity and stability of the positioning. The implementation of this mechanism enables the underwater detector to maintain high-precision positioning even in the absence of GPS signals or weak signals, not only improving the reliability and stability of positioning, but also significantly enhancing the adaptability of the system in complex underwater environments.

[0074] Embodiment 3

[0075] This embodiment is an explanation and illustration in Embodiment 2, please refer to Figure 1 and Figure 3 , specifically: S2 includes S21 and S22;

[0076] S21, after the Beidou navigation system signal is attenuated to less than or equal to -20dB, the inertial navigation system just intervenes in the positioning supplement of the underwater detector, the Beidou navigation system positioning information at this time is set as the initial coordinate ins0=(x0, y0, z0), and the initial velocity vector v0 recorded by the inertial measurement unit of the underwater detector is obtained, wherein x0, y0 and z0 represent the initial longitude coordinate, the initial latitude coordinate and the initial diving depth of the underwater detector, respectively;

[0077] S22, when the underwater detector continues to move, the acceleration components of the underwater detector in the x-axis, y-axis and z-axis directions are obtained by the accelerometer, gyroscope and magnetometer integrated in the inertial measurement unit, respectively, and the acceleration vector a(t) of the underwater detector at time t is obtained by summarizing, specifically: a(t)=(a x (t), a y (t), a z (t)), wherein a x (t), a y (t), a z (t) represent the acceleration components of the acceleration in the x-axis, y-axis and z-axis directions at time t, respectively;

[0078] The x-axis, y-axis and z-axis directions represent the east-west flow direction of seawater, the south-north flow direction of seawater and the high-low flow direction of seawater, respectively;

[0079] S23, the velocity vector v(t) of the underwater detector at time t is calculated by time integration according to the obtained acceleration vector a(t), specifically: In the formula, a(t) represents the acceleration vector at time t, and dt represents the time differential;

[0080] The inertial navigation system calculates the preliminary inertial navigation position vector ins(t) according to the obtained velocity vector v(t), specifically: In the formula.

[0081] In this embodiment, by recording the positioning information of the Beidou navigation system in real time and taking it as the initial coordinates, the inertial navigation system can continuously calculate and update the acceleration vector a(t) and the velocity vector v(t) based on the initial positioning combined with the data collected by the inertial measurement unit of the underwater probe, such as the measurement results of the accelerometer, gyroscope and magnetometer. Through the time integration process, the displacement and velocity change of the underwater probe can be accurately calculated, ensuring that even if the GPS signal gradually weakens or disappears in the complex underwater environment, the inertial navigation system can still accurately provide position information. This real-time positioning correction and velocity tracking mechanism significantly enhances the adaptability and robustness of the system in the underwater environment, enabling stable maintenance of high-precision positioning in seawater flow and dynamic environments, providing reliable navigation support for underwater tasks.

[0082] Embodiment 4

[0083] This embodiment is an explanation and description in Embodiment 3, please refer to Figure 1 and Figure 3 Specifically, S3 includes S31 and S32;

[0084] S31, through the sonar detector installed on the underwater probe, real-time monitoring the depth and surrounding obstacles of the underwater probe, and feeding back to the inertial navigation system for positioning correction, specifically including S311, S312 and S313;

[0085] S311, through the real-time water depth information so(t) provided by the sonar at time t, and the water depth in(t) calculated by the inertial navigation system at time t, real-time comparison is made to calculate the depth offset hz(t) at time t, and the water depth information of the inertial navigation system is corrected, specifically: hz(t) = so(t) - in(t);

[0086] S312, when the positioning information error of the inertial navigation system accumulates with the running time of the underwater probe, it will cause the position to deviate constantly, through the real-time collection of seawater density md by the densimeter installed outside the underwater probe, after dimensionless processing, combined with the real-time measurement of the distance jl(t) between the underwater probe and the obstacle at time t by the sonar, In the formula, sc0 represents the sound propagation speed under standard water temperature, k1 represents the constant of the influence of seawater density on sound speed, which is obtained through experiment, md0 represents the density of seawater under standard state, md(t) represents the seawater density at time t, and Δt represents the time interval from sound emission to reception;

[0087] The dimensionless processing eliminates the dimensional influence of the navigation data and detailed morphological information by the Max-Min minimization method;

[0088] S313, after obtaining the distance jl(t) between the underwater detector and the obstacle at time t, the dimensionless processing is performed to compare with the distance jl(t-1) between the underwater detector and the obstacle at time t-1, and the offset distance yl(t) at time t is obtained, specifically: yl(t) = jl(t) - jl(t-1);

[0089] The real-time horizontal offset amount hx(t) and the real-time longitudinal offset amount hy(t) of the underwater detector at time t are calculated in real time by a trigonometric function in combination with the real-time heading angle θ(t) of the underwater detector at time t, specifically: hx(t) = yl(t) * cos(θ(t)), hy(t) = yl(t) * sin(θ(t)), wherein, cos represents a cosine function, and sin represents a sine function.

[0090] S32, the position information of the underwater detector is analyzed preliminarily by the inertial navigation system, and positioning evaluation is performed, specifically including S321 and S322;

[0091] S321, the depth offset amount hz(t), the horizontal offset amount hx(t) and the longitudinal offset amount hy(t) are summarized according to the obtained depth offset amount hz(t), the horizontal offset amount hx(t) and the longitudinal offset amount hy(t), and the position offset vector py(t) is obtained, that is, py = (hx, hy, hz).

[0092] S322, the preset error precision modulus A is performed based on the positioning deviation error allowed in the underwater detection navigation technology field, and the positioning deviation evaluation is performed with the obtained position offset vector py(t), and the specific evaluation scheme is as follows:

[0093] When the position offset vector py(t) ≤ error precision threshold A, the positioning precision meets the requirements, normal monitoring is maintained, and the current positioning is output by the inertial navigation system.

[0094] When the position offset vector py(t) > error precision threshold A, the positioning precision does not meet the requirements, and compensation optimization analysis is performed at this time.

[0095] In this embodiment, the water depth information provided by the sonar is compared with the water depth calculated by the inertial navigation system, and the calculated depth offset hz(t) can timely correct the water depth data of the underwater detector, and reduce the deviation caused by the accumulation of positioning error. In addition, by combining the real-time heading angle θ(t) of the underwater detector, the lateral offset hx(t) and the longitudinal offset hy(t) are further corrected by the real-time collected seawater density data and the obstacle distance jl(t) measured by the sonar, and the position offset vector py(t) is obtained by summarizing, that is, py=(hx, hy, hz), and the positioning deviation is evaluated with the preset error precision module A. This comprehensive correction mechanism is particularly important in dynamic water areas, because it can effectively overcome the error caused by environmental factors, thereby ensuring the continuous high-precision positioning of the underwater detector. Through the evaluation and optimization of the positioning deviation, the positioning information can be continuously and stably output when the accuracy meets the requirements, and the positioning ability and reliability of the underwater detector are significantly improved.

[0096] Embodiment 5

[0097] This embodiment is an explanation and description in embodiment 4, please refer to Figure 1 and Figure 3 , specifically: S4, executing relevant instructions based on the evaluation results of the positioning deviation evaluation, specifically including S41 and S42;

[0098] S41, when the positioning accuracy meets the requirements, the position offset vector py(t) obtained by the sonar auxiliary positioning and the preliminary inertial navigation position ins(t) obtained by the inertial navigation system are comprehensively calculated to obtain the actual output position vector scw(t) of the inertial navigation system at time t, specifically: scw(t)=ins(t)-py(t);

[0099] S42, when the preliminary accuracy evaluation is not satisfied, execute compensation optimization analysis;

[0100] The compensation optimization analysis includes water flow influence analysis and sonar influence analysis;

[0101] The water flow influence analysis collects the flow velocity components l x (t), l y (t) and l z (t) of seawater in x-axis direction, y-axis direction and z-axis direction at time t through the water flow sensor installed outside the underwater detector, and the dimensionless processing is summarized as seawater flow velocity three-dimensional vector, which is represented as ls(t)=(l x (t), l y (t), lz (t)),water flow will change the speed and trajectory of the underwater probe, and the inertial navigation system corrects the position of the underwater probe by acquiring the three-dimensional vector of the sea water flow velocity ls(t), and the flow influence correction vector flo(t) at time t is obtained by formula calculation, and the correction formula is as follows: In the formula, ls(t) represents the three-dimensional vector of the sea water flow velocity ls at time t, γ represents the influence coefficient of the flow on the inertial navigation error, and dt represents the time differential quantity.

[0102] The sonar influence analysis is based on the influence of the sonar signal existing in the sea water environment, a sonar compensation correction formula is constructed through the inertial navigation system, and the influence coefficient and the attenuation coefficient of the sonar signal are introduced, and then the influence coefficient and the attenuation coefficient are input into the sonar compensation correction formula, and the sonar influence correction vector sxz(t) at time t is output, so as to optimize the influence of the reflection intensity of the sonar on the error of the obstacle position discrimination, and the specific process is as follows: In the formula, T represents the total monitoring time interval, I ech (t) represents the intensity vector of the received echo signal in the three-dimensional space under the sea at time t, which reflects the propagation attenuation and reflection characteristics of the sound wave in different directions, w1 represents the initial influence coefficient of the sonar reflection intensity, which reflects the transmission power of the sonar system and the initial propagation amplitude of the sound wave, w2 represents the attenuation coefficient of the propagation distance on the influence of the sound wave transmission, exp represents the exponential decay function, and cz represents the three-dimensional position vector of the reflected object.

[0103] In this embodiment, when the preliminary accuracy evaluation meets the requirements, the position offset vector py(t) obtained through the sonar auxiliary positioning is combined with the preliminary inertial navigation position ins(t) of the inertial navigation system, and the actual output position vector scw(t) of the inertial navigation system is calculated, so as to effectively reduce the positioning deviation caused by the inertial navigation error. When the positioning accuracy does not meet the requirements, the compensation optimization analysis is automatically started, the flow influence analysis and the sonar influence analysis are combined, the three-dimensional vector ls(t) of the sea water flow velocity is collected in real time, and the interference of the flow on the positioning accuracy is corrected. The influence of the flow on the inertial navigation error is effectively corrected, so that the underwater probe can cope with the dynamically changing flow environment. At the same time, the sonar compensation correction introduces the attenuation coefficient and the influence coefficient of the sonar echo signal, optimizes the influence of the sonar on the error of the obstacle position discrimination, and further improves the positioning ability of the system in the complex underwater environment. This comprehensive optimization correction mechanism not only enhances the adaptability of the underwater probe to external interference, but also greatly improves the positioning accuracy and stability, and ensures that the probe can continuously provide high-precision position information in unstable environment.

[0104] Embodiment 6

[0105] This embodiment is an explanation and description in embodiment 5, please refer to Figure 1and Figure 3 Specifically, S5 includes S51 and S52.

[0106] S51, according to the obtained position offset vector py(t), the water flow influence correction vector flo(t) and the sonar influence correction vector sxz(t), comprehensive summary calculation is performed to obtain the comprehensive optimization correction position vector yxh(t) at time t, specifically: In the formula, T represents the total monitoring time interval.

[0107] S52, according to the obtained comprehensive optimization correction position vector yxh and the preset error precision modulus A, the modified positioning deviation is evaluated, and the specific evaluation scheme is as follows:

[0108] When the comprehensive optimization correction position vector yxh(t) is greater than the error precision threshold A, the positioning precision after correction does not meet the requirements.

[0109] When the comprehensive optimization correction position vector yxh(t) is less than or equal to the error precision threshold A, the positioning precision after correction meets the requirements, and normal monitoring is maintained.

[0110] After the modified positioning deviation is evaluated, the obtained comprehensive optimization correction position vector yxh(t) and the preliminary inertial navigation position ins(t) obtained by the inertial navigation system are comprehensively calculated to obtain the optimized actual position vector ycw(t) of the inertial navigation system, specifically: ycw(t) = ins(t) - yxh(t).

[0111] When the modified positioning deviation evaluation is that the positioning precision does not meet the requirements, the obtained optimized actual position vector ycw(t) is subjected to iterative evaluation through S4.

[0112] When the modified positioning deviation evaluation is that the positioning precision meets the requirements, the optimized actual position vector ycw(t) is output by the inertial navigation system.

[0113] In this embodiment, by comprehensively optimizing the calculation of the position vector yxh(t) and comparing it with the preset error accuracy modulus A, the positioning deviation can be effectively identified and eliminated, thereby significantly improving the positioning accuracy. When the comprehensively optimized position vector yxh(t) meets the accuracy requirement, the inertial navigation system can output the optimized actual position vector ycw(t), ensuring that the underwater probe can continuously provide accurate positioning information in complex environments. During the post-correction positioning deviation evaluation process, when the accuracy does not meet the requirement, further correction can be performed through iterative optimization to ensure that the positioning accuracy gradually reaches or exceeds the predetermined standard. The special benefit of this process is that it realizes continuous optimization and adaptive adjustment of positioning accuracy, through dynamic correction and accurate error evaluation, ensuring that the underwater probe can always maintain high-precision positioning in dynamic and complex underwater environments, avoiding positioning failure caused by error accumulation or external interference in traditional methods.

[0114] Embodiment 7

[0115] Please refer to Figure 2 A Beidou inertial navigation positioning system, comprising a navigation component module, a position analysis module, a position accuracy evaluation module, an accuracy correction module, and a comprehensive correction evaluation module.

[0116] The navigation component module is used to equip the underwater probe with a Beidou navigation system and an inertial navigation system, and to start the inertial navigation system for positioning correction when the Beidou navigation system signal decays to less than or equal to -20 dB.

[0117] The position analysis module is used to calibrate the Beidou navigation system positioning information at this time as the initial coordinates and record the current velocity vector v0 when the inertial navigation system just intervenes in the positioning supplement of the underwater probe, and to analyze the inertial navigation position of the underwater probe in real time through the inertial measurement unit.

[0118] The position accuracy evaluation module is used to analyze the depth deviation, lateral deviation, and longitudinal deviation in real time through the sonar probe for positioning correction of the inertial navigation system, and to evaluate the positioning deviation after summarizing.

[0119] The accuracy correction module is used to output the position vector when the positioning accuracy meets the requirement, and to perform flow influence analysis and sonar influence analysis when the positioning accuracy does not meet the requirement.

[0120] The comprehensive correction evaluation module is used to perform comprehensive optimization of the positioning analysis according to the position accuracy evaluation module and the accuracy correction module, and to perform post-correction positioning deviation evaluation. When the evaluation result is that the positioning accuracy does not meet the requirement, iterative optimization is performed, and when the positioning accuracy meets the requirement, the position vector is output.

[0121] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A BeiDou inertial navigation and positioning method, characterized in that: Includes the following steps: S1. The underwater detector is equipped with a Beidou navigation system and an inertial navigation system respectively. After the Beidou navigation system signal attenuates to less than or equal to -20dB, the inertial navigation system is activated to perform positioning correction. S2. When the inertial navigation system first intervenes to supplement the positioning of the underwater detector, the positioning information of the Beidou navigation system at this time is calibrated as the initial coordinates, and the current velocity vector v0 is recorded. Then, the inertial navigation position of the underwater detector is analyzed in real time through the inertial measurement unit. S3. The inertial navigation system is corrected by using a sonar detector, and the depth offset, lateral offset and longitudinal offset are analyzed in real time. The results are then summarized to evaluate the positioning deviation. S4. When the positioning accuracy meets the requirements, output the position vector; when the positioning accuracy does not meet the requirements, perform water flow influence analysis and sonar influence analysis. S5. Based on S3 and S4, perform comprehensive optimization and positioning analysis, and evaluate the corrected positioning deviation. If the evaluation result shows that the positioning accuracy does not meet the requirements, perform iterative optimization. If the positioning accuracy meets the requirements, output the position vector.

2. The BeiDou inertial navigation and positioning method according to claim 1, characterized in that: S1 includes S11 and S12; S11. The underwater probe is equipped with a Beidou navigation system and an inertial navigation system respectively. When the underwater probe is started, it first receives Beidou satellite signals through the Beidou navigation system to determine the initial position of the equipment. Before diving, the Beidou navigation system provides the underwater probe with initial positioning information. S12. When the underwater probe begins to descend, the GPS signal will be gradually limited. After the Beidou navigation system signal attenuates to less than or equal to -20dB, the underwater probe will be positioned and compensated in real time through the inertial navigation system. The inertial measurement unit equipped with the underwater probe will be used to monitor the motion state of the underwater probe in the underwater three-dimensional space in real time. The inertial measurement unit integrates an accelerometer, a gyroscope, and a magnetometer.

3. The BeiDou inertial navigation and positioning method according to claim 2, characterized in that: S2 includes S21 and S22; S21. When the BeiDou navigation system signal attenuates to less than or equal to -20dB and the inertial navigation system just intervenes to supplement the underwater probe's positioning, the BeiDou navigation system positioning information at this time is set as the initial coordinates ins0 = (x0, y0, z0), and the initial velocity vector v0 is recorded according to the underwater probe's inertial measurement unit, where x0, y0, and z0 represent the initial longitude coordinates, initial latitude coordinates, and the initial diving depth of the underwater probe, respectively. S22. While the underwater probe is in continuous motion, the acceleration components of the underwater probe in the x-axis, y-axis, and z-axis directions are obtained by the accelerometer, gyroscope, and magnetometer integrated in the inertial measurement unit, respectively. These components are then summarized to obtain the acceleration vector a(t) of the underwater probe at time t, specifically: a(t) = (a x (t), a y (t), a z (t)), where a x (t), a y (t), a z (t) represent the acceleration components in the x-axis, y-axis and z-axis directions at time t, respectively; The x-axis, y-axis, and z-axis represent the east-west flow of seawater, the north-south flow of seawater, and the vertical flow of seawater, respectively. S23. Based on the obtained acceleration vector a(t), the velocity vector v(t) of the underwater probe at time t is calculated by time integration, specifically: In the formula, a(t) represents the acceleration vector at time t, and dt represents the time differential quantity; The inertial navigation system calculates the preliminary inertial navigation position vector ins(t) based on the acquired velocity vector v(t), specifically:

4. The BeiDou inertial navigation and positioning method according to claim 3, characterized in that: S3 includes S31 and S32; S31. The depth of the underwater detector and surrounding obstacles are monitored in real time by the sonar detector installed on the underwater detector, and the feedback is sent to the inertial navigation system for positioning correction. Specifically, this includes S311, S312 and S313. S311. The real-time water depth information so(t) provided by the sonar at time t is compared with the water depth in(t) calculated by the inertial navigation system at time t in real time. The depth offset hz(t) at time t is calculated and the water depth information of the inertial navigation system is corrected. Specifically: hz(t) = so(t) - in(t). S312. When the positioning information error of the inertial navigation system accumulates over time as the underwater detector operates, the seawater density md is collected in real time by a density meter installed outside the underwater detector. After dimensionless processing, the distance jl(t) between the underwater detector and the obstacle at time t is measured in real time by sonar. In the formula, sc0 represents the speed of sound propagation at standard water temperature, k1 represents the constant of the effect of seawater density on the speed of sound, which is obtained through experiments, md0 represents the density of seawater under standard conditions, md(t) represents the density of seawater at time t, and Δt represents the time interval between the transmission and reception of the sound wave. S313. After obtaining the distance jl(t) between the underwater detector and the obstacle at time t, compare it with the distance jl(t-1) between the underwater detector and the obstacle at time t-1 after dimensionless processing to obtain the offset distance yl(t) at time t, specifically: yl(t)=jl(t)-jl(t-1); Then, by combining the real-time heading angle θ(t) of the underwater probe at time t, the lateral offset hx(t) and longitudinal offset hy(t) of the underwater probe at time t are calculated in real time using trigonometric functions. Specifically, hx(t) = yl(t) * cos(θ(t)) and hy(t) = yl(t) * sin(θ(t)), where cos represents the cosine function and sin represents the sine function.

5. The BeiDou inertial navigation and positioning method according to claim 4, characterized in that: S32. The underwater detector's position information is initially analyzed through the inertial navigation system, and a positioning assessment is performed, specifically including S321 and S322. S321. Based on the obtained depth offset hz(t), lateral offset hx(t), and longitudinal offset hy(t), the position offset vector py(t) is obtained, i.e., py = (hx, hy, hz).

6. The BeiDou inertial navigation and positioning method according to claim 5, characterized in that: S322. Based on the industry-permitted positioning deviation error in the field of underwater detection and navigation technology, a preset error accuracy modulus A is made, and the positioning deviation is evaluated with the obtained position offset vector py(t). The specific evaluation scheme is as follows. When the position offset vector py(t) ≤ the error accuracy threshold A, the positioning accuracy meets the requirements, normal monitoring is maintained, and the current positioning is output through the inertial navigation system; When the position offset vector py(t) is greater than the error accuracy threshold A, the positioning accuracy does not meet the requirements, and compensation optimization analysis is performed.

7. The BeiDou inertial navigation and positioning method according to claim 6, characterized in that: S4. Execute relevant instructions based on the evaluation results of the positioning deviation assessment, specifically including S41 and S42; S41. Once the positioning accuracy meets the requirements, the position offset vector py(t) obtained by sonar-assisted positioning and the preliminary inertial navigation position ins(t) obtained by the inertial navigation system are combined to calculate the actual output position vector scw(t) of the inertial navigation system at time t, specifically: scw(t) = ins(t) - py(t). S42. When the initial accuracy assessment indicates that the requirements are not met, perform compensation optimization analysis. Compensation optimization analysis includes water flow impact analysis and sonar impact analysis; The water flow impact analysis uses a water flow sensor installed outside the underwater detector to collect the flow velocity components l of seawater in the x-axis, y-axis, and z-axis directions in real time at time t. x (t), l y (t) and l z (t), after dimensionless processing, is summarized into a three-dimensional vector of seawater velocity, which is expressed as ls(t)=(l x (t), l y (t), l z The water flow will change the speed and trajectory of the underwater detector. The inertial navigation system corrects the position of the underwater detector by acquiring the three-dimensional vector ls(t) of the seawater flow velocity. The water flow influence correction vector flo(t) at time t is calculated by the following formula: In the formula, ls(t) represents the three-dimensional vector ls of the seawater flow velocity at time t, γ represents the influence coefficient of the water flow on the inertial navigation error, and dt represents the time differential quantity; The sonar impact analysis is based on the influence of sonar signals in the seawater environment. A sonar compensation correction formula is constructed using an inertial navigation system, incorporating the influence coefficient and attenuation coefficient of the sonar signal. These coefficients are then input into the sonar compensation correction formula, outputting the sonar impact correction vector sxz(t) at time t. This optimizes the impact of sonar reflection intensity on obstacle location discrimination error, as detailed below: In the formula, T represents the total monitoring time interval, and I ech (t) represents the intensity vector of the echo signal received in the three-dimensional space underwater at time t, w1 represents the initial influence coefficient of the sonar reflection intensity, w2 represents the attenuation coefficient of the influence of the propagation distance on the sound wave transmission, exp represents the exponential attenuation function, and cz represents the three-dimensional position vector of the reflecting object.

8. A BeiDou inertial navigation and positioning method according to claim 7, characterized in that: S5 includes S51 and S52; S51. Based on the obtained position offset vector py(t), water flow influence correction vector flo(t), and sonar influence correction vector sxz(t), a comprehensive calculation is performed to obtain the comprehensive optimized correction position vector yxh(t) at time t, specifically: In the formula, T represents the total monitoring time interval.

9. A BeiDou inertial navigation and positioning method according to claim 8, characterized in that: S52. Based on the obtained comprehensive optimized and corrected position vector yxh and the preset error precision modulus A, the corrected positioning deviation is evaluated. The specific evaluation scheme is as follows. When the comprehensive optimization correction position vector yxh(t) > the error accuracy threshold A, the corrected positioning accuracy does not meet the requirements. When the comprehensive optimization and correction of the position vector yxh(t) ≤ the error accuracy threshold A, the corrected positioning accuracy meets the requirements and normal monitoring is maintained. After the positioning deviation is evaluated, the optimized corrected position vector yxh(t) and the preliminary inertial navigation position ins(t) obtained by the inertial navigation system are combined to calculate the optimized actual position vector ycw(t) of the inertial navigation system, specifically: ycw(t) = ins(t) - yxh(t); When the corrected positioning deviation is assessed as not meeting the positioning accuracy requirements, the optimized actual position vector ycw(t) is used to perform iterative evaluation through S4. If the corrected positioning deviation is assessed as meeting the positioning accuracy requirements, the optimized actual position vector ycw(t) is output through the inertial navigation system.

10. A BeiDou inertial navigation and positioning system, comprising the BeiDou inertial navigation and positioning method according to any one of claims 1-9, characterized in that: It includes a navigation component module, a position analysis module, a position accuracy assessment module, an accuracy correction module, and a comprehensive correction and assessment module; The navigation module is used to equip the underwater detector with the Beidou navigation system and the inertial navigation system respectively. After the Beidou navigation system signal attenuates to less than or equal to -20dB, the inertial navigation system is activated to perform positioning correction. The position analysis module is used to calibrate the BeiDou navigation system positioning information as the initial coordinates when the inertial navigation system first intervenes to supplement the positioning of the underwater detector, and to record the current velocity vector v0. Then, the inertial measurement unit analyzes the inertial navigation position of the underwater detector in real time. The position accuracy assessment module is used to correct the positioning of the inertial navigation system using sonar detectors, analyze depth offset, lateral offset and longitudinal offset in real time, and summarize them to assess the positioning deviation. The accuracy correction module is used to output the position vector when the positioning accuracy meets the requirements, and to perform water flow influence analysis and sonar influence analysis when the positioning accuracy does not meet the requirements. The comprehensive correction and evaluation module is used to perform comprehensive optimization and positioning analysis based on the position accuracy evaluation module and the accuracy correction module, and to evaluate the positioning deviation after correction. If the evaluation result shows that the positioning accuracy does not meet the requirements, iterative optimization is performed. If the positioning accuracy meets the requirements, the position vector is output.

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