CN115390120A - Early warning method for collision avoidance of offshore platform and ship and storage medium - Google Patents

Early warning method for collision avoidance of offshore platform and ship and storage medium Download PDF

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CN115390120A
CN115390120A CN202210954232.5A CN202210954232A CN115390120A CN 115390120 A CN115390120 A CN 115390120A CN 202210954232 A CN202210954232 A CN 202210954232A CN 115390120 A CN115390120 A CN 115390120A
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ship
offshore platform
platform
distance
offshore
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彭瀚
童赛美
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No 750 Test Field of China Shipbuilding Industry Corp
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No 750 Test Field of China Shipbuilding Industry Corp
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/42—Determining position
    • G01S19/43—Determining position using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
    • G01S19/44—Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/20—Instruments for performing navigational calculations
    • G01C21/203—Specially adapted for sailing ships
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/40—Correcting position, velocity or attitude
    • G01S19/41—Differential correction, e.g. DGPS [differential GPS]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
    • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/53—Determining attitude
    • G01S19/54—Determining attitude using carrier phase measurements; using long or short baseline interferometry
    • G01S19/55—Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T17/00—Three dimensional [3D] modelling, e.g. data description of 3D objects
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G3/00—Traffic control systems for marine craft
    • G08G3/02—Anti-collision systems

Abstract

The invention discloses a collision prevention early warning method for an offshore platform and ships and a storage medium, the method obtains carrier attitude information of each ship (platform) by double-antenna attitude measurement and satellite positioning technology, realizes modeling of the outline of each ship (platform) by combining three-dimensional scale information of each ship (platform), takes the platform as a differential reference station, transmits carrier observed quantity and positioning information of each operation ship to surrounding mobile stations through a data chain in real time by a base station on each operation ship, performs differential processing with phase observed quantity of the mobile stations, realizes accurate positioning of relative spatial position relation of each ship (platform), adjusts a three-dimensional model, can visually display three-dimensional real scenes on each ship (platform), and sends an alarm to the ship with collision risk so as to reduce the probability of collision accidents between the offshore operation ship and a production platform.

Description

Early warning method for collision avoidance of offshore platform and ship and storage medium
Technical Field
The invention relates to the technical field of ship collision avoidance early warning, in particular to an offshore platform and ship collision avoidance early warning method and a storage medium.
Background
In recent years, along with the rapid development of technologies such as artificial intelligence and smart oceans, unmanned defense systems such as underwater security become research hotspots and difficulties. In the production process of the offshore oil and gas platform, various production and living materials ensure that a ship can stop the platform to carry out loading and unloading or engineering operation, so that the accident that the ship collides the platform is inevitable, and the loss is caused to the offshore oil and gas production and the personnel safety. In order to reduce or avoid such accidents, platform collision avoidance systems are imperative.
The intelligent collision avoidance decision of the ship is beneficial to improving the safety of ship navigation, reducing the influence of human factors and the labor amount of people, has important significance on the development of the world shipping industry, and is a main and important research direction for a period of time in the future. Aiming at the current situation, countries in the world begin research work of intelligent ship collision avoidance and obtain certain research results. China's research on intelligent ship collision avoidance begins in the 80's of the 20 world. In the operation process of the water surface vehicle, the support ship is often required to keep straight navigation at a constant speed as much as possible on a planned navigation line, however, the operation ship is inevitably influenced by the comprehensive effects of various factors such as wind, current, wave and surge on the sea and is frequently corrected by a driver in real time, so that the navigation track of the support ship is irregularly changed, the positioning error is generated due to the updating or re-stabilization of equipment data such as a GPS compass and an attitude, and the navigation precision of an acoustic navigation system is reduced due to the unstable environment during navigation.
An Automatic Identification System (AIS) of ship is an international standard system for preventing ship from collision during navigation, and its principle is that GPS positioning system is used to obtain the position, speed and course of ship, and UHF communication network and relative protocol are used to transmit relative information to each other for realizing automatic identification of ship. Because the ship information in the AIS system is only a point source target containing GPS position information (with the error of ten meters), although the dimension information of the ship is derived by combining the course information in the navigation process and the registration information, the ship does not have obvious course information when the ship works near the platform in a floating or dynamic positioning state, and the updating rate of the position information is limited by a communication protocol and sometimes reaches several minutes, so the AIS system cannot be directly used for avoiding collision between the platform and the working ship based on the three aspects.
Disclosure of Invention
Aiming at the problems, the inventor provides an offshore platform and ship collision avoidance early warning method and a storage medium which integrate double-antenna attitude measurement and differential positioning, so that high-precision positioning of the three-dimensional space relative position relation between a test platform and each operation ship is realized, the probability of collision accidents between the offshore operation ship and a production platform is reduced, and the loss caused by the accidents is reduced.
According to a first aspect, the invention provides a collision avoidance early warning method for an offshore platform and a ship, comprising the following steps:
step S1: a double-antenna attitude measurement system is arranged on the offshore platform and the ship;
constructing a differential positioning system, wherein an offshore platform is used as a reference station, and a ship is used as a mobile station;
step S2: acquiring the position of an offshore platform, the position of a ship and the posture of the ship based on a double-antenna attitude measurement system;
and step S3: carrying out digital derivation on three-dimensional scale information on the outline of the offshore platform and the ship, constructing appearance models of the offshore platform and the ship, and adjusting the appearance models by using the position of the offshore platform, the position of the ship and the ship posture to obtain a three-dimensional model containing the position of the offshore platform, the position of the ship and the ship posture;
and step S4: correcting the position of the ship based on a differential positioning system, and synchronously adjusting a three-dimensional model;
step S5: determining the geometric center distance and the edge distance of the three-dimensional model, the offshore platform position, the ship attitude and the corrected ship position based on the adjusted three-dimensional model;
step S6: and when the geometric center distance is the distance sum of the geometric center distance and the edge distance is larger than the minimum distance interval threshold, giving an alarm.
Further, in the step S3, the step of constructing the external shape models of the offshore platform and the ship includes:
s31: obtaining appearance discrete point data of an offshore platform and a ship;
s32: reducing the data volume of the outline discrete point data by using precision comparison software;
s33: extracting the geometric characteristics of the appearance of the offshore platform and the ship, and performing geometric segmentation according to discrete point data;
s34: performing surface characteristic curve fitting, curved surface fitting, intersection cutting and splicing to realize the reconstruction of the appearance model of the offshore platform and the ship;
s35: and correcting and checking the geometric shape of the model, checking whether the difference between the geometric shape and the discrete point data meets the precision requirement, and if not, optimizing and adjusting the model until the precision requirement is met.
Further, the step of adjusting the shape model by using the position of the offshore platform, the position of the ship and the attitude to obtain a three-dimensional model including the position of the offshore platform, the position of the ship and the attitude of the ship comprises the following steps:
calculating the offshore platform position, the ship position and the ship posture to obtain a three-dimensional model image gray value, and obtaining a mapping relation between the offshore platform position, the ship position and the ship posture and a gray value function according to the three-dimensional model image gray value;
calculating the Euclidean distance between each pixel of the offshore platform and the geometric centroid of all ships by taking the screen coordinate of the three-dimensional space model modeling area as a reference;
substituting the Euclidean distance into a kernel density function to obtain a probability density estimation value of the distance between each pixel of the offshore platform and the geometric centroid of all ships;
superposing all positive platform probability density estimated values to obtain a total probability density estimated value of a platform coverage pixel point;
normalizing the total probability density estimation value to obtain each pixel point value;
and building a three-dimensional space model based on the pixel point values.
Further, it is assumed that the offshore platform is covered by n pixel points, m ships exist around the offshore platform, and the screen coordinates (x) corresponding to the platform pixel points i ，y i ) The ship corresponds to the screen coordinate of (x) j ，y j ) Distance D from offshore platform pixel point to ship centroid ij Comprises the following steps:
Figure BDA0003790519780000031
further, the platform probability density estimate
Figure BDA0003790519780000032
Comprises the following steps:
Figure BDA0003790519780000033
wherein D is ij (x, y) represents the distance from the offshore platform pixel point to the ship centroid; h represents the window width of the kernel density estimate; h = (4/3) 1/5 n -1/5 [f i (D ij )/l] -γ ，
Figure BDA0003790519780000034
Sensitivity coefficient γ =0.5.
Further, pixel point values v ij Comprises the following steps:
Figure BDA0003790519780000035
wherein the content of the first and second substances,
Figure BDA0003790519780000036
representing an overall probability density estimate; v. of min Is v is ij Minimum over all samples; v. of max Is v ij Maximum over all samples.
Further, in the step S5, the step of obtaining the edge distance includes:
pixel point value v ij With the centre v of the vessel c The pixel interval of (1) is converted into an actual physical distance to obtain an edge distance; edge distance D p Comprises the following steps:
Figure BDA0003790519780000041
wherein the pixel point values v ij The corresponding image grid cell coordinate is (x) ij ,y ij ) The resolution grid interval of the pixel grid unit corresponding to the actual physical distance is delta d p Central pixel point v c The corresponding grid cell coordinate is (x) c ,y c )。
According to a second aspect, the invention also provides a computer-readable storage medium having stored thereon a computer program executable by a processor to implement the steps of the method as described above.
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the anti-collision early warning method for the offshore platform and the ship, provided by the invention, a mode of integrating double-antenna attitude measurement and differential positioning is adopted, so that the attitude measurement precision of the carrier system can be improved, and quick and high-precision alignment can be realized, so that the positioning requirement of attitude information of a water surface carrier is met.
(2) The relative position relation of the space outline of the carrier can be realized through the digital derivation mode of the attitude and position positioning data of the ship (platform) and the three-dimensional scale information, the three-dimensional real scene can be visually displayed on each ship (platform), an alarm is sent to the ship with collision risk, the probability of collision accidents between the offshore operation ship and the production platform is favorably reduced, and the loss caused by the accidents is reduced.
Drawings
Fig. 1 is a flow chart of the marine platform and ship collision avoidance early warning method of the present application;
FIG. 2 is a schematic view of the present application of collision avoidance for a vessel;
FIG. 3 is a schematic diagram of the principle of dual antenna attitude measurement;
FIG. 4 is a schematic diagram of a differential positioning system;
FIG. 5 is a schematic diagram of a differential measurement principle;
fig. 6 is a schematic diagram of carrier phase observations.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings.
Example 1
As shown in fig. 1, the invention provides a collision avoidance early warning method for an offshore platform and a ship, comprising the following steps:
step S1: a double-antenna attitude measuring system is arranged on the offshore platform and the ship; the double-antenna attitude measurement system comprises two satellite positioning GPS antennas (not limited to GPS, but also positioning systems such as Granese, beidou or Galileo and the like) and a signal receiver. The receiver antenna may share one antenna with a dual antenna system or may be separated into individual antennas. Namely, the antenna and the receiver are arranged in a separated mode or a centralized mode. When the double antennas are arranged, the base line is required to be coincident with a ship crankshaft, so that the deviation of course measurement of the carrier caused by attitude transformation is reduced.
And constructing a differential positioning system, wherein the offshore platform is used as a reference station, and the ship is used as a mobile station. The GPS receiver collects platform data and broadcasts the platform data to the surrounding mobile operation ships through a radio data link or a GSM telephone.
Step S2: the position of the offshore platform, the position of the ship and the posture of the ship are obtained based on the double-antenna attitude measurement system. The double-antenna attitude measurement is a mature technology, and the principle is as follows:
the satellite positioning signal to the double antenna can be regarded as a far field signal, the received satellite signals are approximately parallel, and the coordinate of the bow-stern antenna of the double antenna attitude measurement system under the deck coordinate system is obtained through the satellite signals as (x) 1 ,y 1 ,z 1 ) And (x) 2 ,y 2 ,z 3 ) Then, a baseline vector L pointing from the stern antenna to the bow antenna is expressed as (x) in the ship deck coordinate system L ,y L ,z L ) The base line vector is in the geographical coordinate system of the ship
Figure BDA0003790519780000051
The ship geopolar coordinates are denoted as (R, a, H). R is the length of the measured base line, A is the included angle between the base line vector and the due north direction, and H is the included angle between the base line vector and the local horizontal plane. The following relationship is satisfied:
Figure BDA0003790519780000052
according to the definition of the course angle measured by the double antennas, the course A and the pitch angle H of the carrier can be expressed as
Figure BDA0003790519780000053
Figure BDA0003790519780000054
The yaw angle A and the pitch angle H of the ship (platform) are calculated, the attitude of the carrier is obtained, and the position positioning data of the ship (platform) is obtained through the IMU.
Differentiating the two formulas, and neglecting the correlation between the coordinate components to obtain course angle error and pitch angle error:
Figure BDA0003790519780000061
Figure BDA0003790519780000062
wherein, L is the length of the base line, and sigma represents the error estimation value and can be obtained by a GNSS positioning model.
And step S3: and carrying out digital derivation on three-dimensional scale information on the outline of the offshore platform and the ship, and constructing the outline models of the offshore platform and the ship. The method adopts and is not limited to modeling software Solidworks/3dMax/sketchup, the modeling mode adopts a reverse modeling mode, and the appearance of the model is established based on the existing platform (ship) model target. The specific process is as follows:
s31: and (3) acquiring appearance discrete point data of the offshore platform and the ship by adopting a three-dimensional laser scanner and a three-coordinate measuring machine, and storing the appearance discrete point data as a database.
S32: and reducing the data volume of the data of the outline discrete point by using precision comparison software, for example, adopting splicing and filtering blocking operations.
S33: and acquiring the appearance geometric characteristics of the offshore platform and the ship in a set characteristic matching and identifying mode, and performing geometric segmentation according to discrete point data.
S34: performing surface characteristic curve fitting, curved surface fitting, intersection cutting and splicing to realize the reconstruction of the offshore platform and the ship appearance model;
s35: and correcting and checking the geometric shape of the model, checking whether the difference between the geometric shape and the discrete point data meets the precision requirement, and if not, optimizing and adjusting the model until the precision requirement is met.
And adjusting the appearance model by using the offshore platform position, the ship position and the ship posture to obtain a three-dimensional model comprising the offshore platform position, the ship position and the ship posture. The specific process is as follows:
and performing operation processing on the offshore platform position, the ship position and the ship posture to obtain a three-dimensional model image gray value, and obtaining a mapping relation between the offshore platform position, the ship position and the ship posture and a gray value function according to the three-dimensional model image gray value.
And calculating the distance between each pixel of the offshore platform and the geometric centroid of all ships by taking the screen coordinate of the three-dimensional space model modeling area as a reference. The offshore platform is covered by n pixel points, m ships exist around the offshore platform, and the screen coordinates (x) corresponding to the platform pixel points i ，y i ) The corresponding screen coordinate of the ship is (x) j ，y j ) Distance D from offshore platform pixel point to ship centroid ij Comprises the following steps:
Figure BDA0003790519780000071
will be at a distance D ij The kernel density function is brought in to obtain the probability density estimated value of the distance between each pixel of the offshore platform and the geometric centroid of all ships
Figure BDA0003790519780000072
Figure BDA0003790519780000073
Wherein D is ij (x, y) represents the distance from the offshore platform pixel point to the ship centroid; h represents the window width of the kernel density estimate; h = (4/3) 1/5 n -1/5 [f i (D ij )/l] -γ ，
Figure BDA0003790519780000074
Sensitivity coefficient γ =0.5.
Overlapping all positive platform probability density estimated values to obtain a total probability density estimated value of a platform coverage pixel point
Figure BDA0003790519780000075
Figure BDA0003790519780000076
Estimating the total probability density by adopting a maximum and minimum normalization method
Figure BDA0003790519780000077
Normalizing to obtain the value v of each pixel point ij 。
Figure BDA0003790519780000078
Wherein v is min Is v is ij Minimum over all samples; v. of max Is v ij Maximum over all samples.
Based on pixel point values v ij And building a three-dimensional space model.
And step S4: and correcting the position of the ship based on a differential positioning system, and synchronously adjusting the three-dimensional model. After receiving the CMR message sent by the reference station, the mobile station (ship) receiver carries out carrier phase calculation in real time. After the integer ambiguity is calculated, the high-precision three-dimensional space relative position positioning under the dynamic state can be realized.
The process is a mature technology and the principle is as follows:
receiver T i In-station clock epoch t i The satellite carrier signal received at the moment is the satellite clock at t j The phase value of the transmitted signal at a time is the phase difference between the two signals.
Figure BDA0003790519780000079
In the formula (I);
Figure BDA00037905197800000710
as a satellite S j In epoch t j The phase of the carrier signal transmitted at any moment;
Figure BDA00037905197800000711
for receiver T i In epoch t i The phase of the time reference carrier signal; phi ij For the above-mentioned two signal phase difference, the difference result is expressed as whole-cycle number and fractional number portion, i.e. has
Figure BDA0003790519780000081
Because the receiver can actually measure only a part less than a whole circle when the carrier phase measurement is carried out
Figure BDA0003790519780000082
However, since the carrier wave is a cosine wave without an identification mark, the fractional part of the whole cycle which is measured cannot be determined, so that the whole cycle ambiguity needs to be determined.
When the satellite signal is in epoch t 0 After being tracked (locked), the total phase difference of any epoch t thereafter is obtained as follows:
Figure BDA0003790519780000083
wherein: n is a radical of hydrogen ij (t 0 ) Determining a constant integer ambiguity, N, for a signal after it has been locked ij (t-t 0 ) Representing observation epoch t from the start 0 The number of whole cycles of carrier phase until the subsequent observation epoch t,
Figure BDA0003790519780000084
the fractional part phase of less than one week at the time of the subsequent observation epoch t.
The carrier phase solution is as follows: actual observed quantity of carrier phase
Figure BDA0003790519780000085
The pseudo-range between the satellites can be obtained by receiving signals through a GPS (global positioning system), and comprises the following steps:
Figure BDA0003790519780000086
where λ is the carrier wavelength. If the real distance rho between the satellites can be obtained by using the known coordinates and the satellite ephemeris at the reference station ij And the pseudo range observed value between the satellite stations is as follows:
Figure BDA0003790519780000087
in the formula, δ M i For multipath effects, V i Is GPS receiver noise.
The pseudorange corrections can be found at the platform reference station:
Figure BDA0003790519780000088
the correction is used to correct the pseudo-range observed value of the mobile station, including
Figure BDA0003790519780000089
As the ship operation condition within 1km range of the platform is concerned in the platform collision avoidance, delta I can be considered jk ＝δI ij ，δT jk ＝δT ij Then, then
Figure BDA00037905197800000810
Figure BDA0003790519780000091
Pseudorange observations of the carrier phase
Figure BDA0003790519780000092
Substituting the above formula to obtain
Figure BDA0003790519780000093
In the above formula, let N j (t 0 )＝N jk (t 0 )-N ij (t 0 ) The difference of the initial integer number of cycles, the difference of the carrier phase measurement
Figure BDA0003790519780000094
Obtaining:
Figure BDA0003790519780000095
due to N j (t 0 )、x k 、y k 、z k The variation quantity of the difference between clock differences of two receivers, the difference of noise and the difference of multipath effect between two stations between adjacent epochs is less than the error allowed by cm-level dynamic positioning, and the variation quantity can also be used in the solving process
Figure BDA0003790519780000096
As a constant. Thus, once the initial whole week is determined, the reference station and the mobile station are located on the platformAnd the mobile station can be positioned by observing the same 4 satellites simultaneously.
Step S5: and determining the geometric center distance and the edge distance of the three-dimensional model, the offshore platform position, the ship attitude and the corrected ship position based on the adjusted three-dimensional model, the offshore platform position, the ship attitude and the corrected ship position. Step 3 shows that the distance between each pixel point of the offshore platform and the center of mass of the ship is D ij The distance between the geometric centers of the two is
Figure BDA0003790519780000097
The ship and the platform are positioned at the same sea level height, the height information of the ship and the platform in the z-axis direction is approximately consistent, and D is selected ij As the distance between the two geometric centers, i.e. D Geo ＝E[D ij |0<i<n,0<j<m]。
Each pixel point value v ij With the centre v of the vessel c The pixel interval of (2) is converted into an actual physical distance to obtain an edge distance D p ＝f(v ij ,v c ). The conversion process is as follows: assuming pixel point values v ij The corresponding image grid cell coordinate is (x) ij ,y ij ) Central pixel point v c The corresponding grid cell coordinate is (x) c ,y c ) The corresponding physical distance of each pixel point is resolved as deltad p That is, the actual distance length corresponding to one grid cell, the edge distance is obtained as follows:
Figure BDA0003790519780000098
step S6: an alarm is issued when the geometric center distance is such that the sum of the distances to the edges is greater than the minimum distance separation threshold.
Minimum distance interval threshold
Figure BDA0003790519780000099
Setting according to the actual physical size parameters of the platform (ship), and generating the following judgment relation:
Figure BDA0003790519780000101
i.e. when the distance between the geometric centers of the two is D Geo Distance D from edge p The sum is greater than the minimum distance interval threshold
Figure BDA0003790519780000102
When, decision A is performed 1 Generating an alarm signal; on the contrary, when the distance between the geometric centers is D Geo Distance D from edge p Sum is less than minimum distance interval threshold
Figure BDA0003790519780000103
When, decision A is performed 0 And no alarm is given.
The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.

Claims (8)

1. An early warning method for preventing collision between an offshore platform and a ship is characterized by comprising the following steps:
step S1: a double-antenna attitude measurement system is arranged on the offshore platform and the ship;
constructing a differential positioning system, wherein an offshore platform is used as a reference station, and a ship is used as a mobile station;
step S2: acquiring the position of an offshore platform, the position of a ship and the posture of the ship based on a double-antenna posture measuring system;
and step S3: carrying out digital derivation on three-dimensional scale information on the appearance profiles of the offshore platform and the ship, constructing appearance models of the offshore platform and the ship, and adjusting the appearance models by using the position of the offshore platform, the position of the ship and the posture of the ship to obtain a three-dimensional model comprising the position of the offshore platform, the position of the ship and the posture of the ship;
and step S4: correcting the position of the ship based on a differential positioning system, and synchronously adjusting a three-dimensional model;
step S5: determining the geometric center distance and the edge distance of the three-dimensional model, the offshore platform position, the ship posture and the corrected ship position based on the adjusted three-dimensional model, the offshore platform position, the ship posture and the corrected ship position;
step S6: and when the geometric center distance is the distance sum of the geometric center distance and the edge distance is larger than the minimum distance interval threshold, giving an alarm.
2. The method of claim 1, wherein the step of constructing the shape model of the offshore platform and the ship in step S3 comprises:
s31: obtaining appearance discrete point data of the offshore platform and the ship;
s32: reducing the data volume of the appearance discrete point data by using precision comparison software;
s33: extracting the appearance geometric characteristics of the offshore platform and the ship, and performing geometric segmentation according to discrete point data;
s34: performing surface characteristic curve fitting, curved surface fitting, intersection cutting and splicing to realize the reconstruction of the offshore platform and the ship appearance model;
s35: and correcting and checking the geometric shape of the model, checking whether the difference between the geometric shape and the discrete point data meets the precision requirement, and if not, optimizing and adjusting the model until the precision requirement is met.
3. The method of claim 2, wherein adjusting the profile model with the position of the offshore platform, the position of the vessel, and the attitude of the vessel to obtain a three-dimensional model including the position of the offshore platform, the position of the vessel, and the attitude of the vessel comprises:
calculating the offshore platform position, the ship position and the ship posture to obtain a three-dimensional model image gray value, and obtaining a mapping relation between the offshore platform position, the ship position and the ship posture and a gray value function according to the three-dimensional model image gray value;
calculating the Euclidean distance between each pixel of the offshore platform and the geometric centroid of all ships by taking the screen coordinate of the three-dimensional space model modeling area as a reference;
substituting the Euclidean distance into a kernel density function to obtain a probability density estimation value of the distance between each pixel of the offshore platform and the geometric centroid of all ships;
superposing all positive platform probability density estimated values to obtain a total probability density estimated value of a platform coverage pixel point;
normalizing the total probability density estimation value to obtain each pixel point value;
and building a three-dimensional space model based on the pixel point values.
4. The method of claim 3, wherein the offshore platform is covered by n pixels, m ships exist around the offshore platform, and the screen coordinates (x) corresponding to the platform pixels are determined i ，y i ) The ship corresponds to the screen coordinate of (x) j ，y j ) The distance from the offshore platform pixel point to the ship centroid is D ij ：
Figure FDA0003790519770000021
5. The method of claim 4, wherein the platform probability density estimate
Figure FDA0003790519770000022
Comprises the following steps:
Figure FDA0003790519770000023
wherein D is ij (x, y) represents the distance from the offshore platform pixel point to the ship centroid; h represents the window width of the kernel density estimate; h = (4/3) 1/5 n -1/5 [f i (D ij )/l] -γ ，
Figure FDA0003790519770000024
Sensitivity coefficient γ =0.5.
6. The method of claim 5, wherein the method further comprises the step of applying a voltage to the substratePixel point value v ij Comprises the following steps:
Figure FDA0003790519770000025
wherein the content of the first and second substances,
Figure FDA0003790519770000026
representing an overall probability density estimate; v. of min Is v is ij Minimum over all samples; v. of max Is v ij Maximum over all samples.
7. The method according to claim 6, wherein in the step S5, the step of obtaining the edge distance comprises:
pixel point value v ij With the centre v of the vessel c The pixel interval of (1) is converted into an actual physical distance to obtain an edge distance; edge distance D p Comprises the following steps:
Figure FDA0003790519770000031
wherein the pixel point values v ij The corresponding image grid cell coordinate is (x) ij ,y ij ) The resolution grid interval of the pixel grid unit corresponding to the actual physical distance is delta d p Central pixel point v c The corresponding grid cell coordinate is (x) c ,y c )。
8. A computer-readable storage medium, on which a computer program is stored, the computer program being executable by a processor for implementing the steps of the method according to any of claims 1-7.
CN202210954232.5A 2022-08-10 2022-08-10 Early warning method for collision avoidance of offshore platform and ship and storage medium Pending CN115390120A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117592787A (en) * 2024-01-16 2024-02-23 交通运输部水运科学研究所 Marine ship safety risk prediction method and electronic equipment

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117592787A (en) * 2024-01-16 2024-02-23 交通运输部水运科学研究所 Marine ship safety risk prediction method and electronic equipment
CN117592787B (en) * 2024-01-16 2024-04-02 交通运输部水运科学研究所 Marine ship safety risk prediction method and electronic equipment

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