Ship self-positioning precision enhancement method and system under GNSS interruption condition

Abstract

The invention provides a ship autonomous positioning precision enhancement method under a GNSS interruption condition, and belongs to the technical field of ship intelligent navigation autonomous positioning. The method comprises the following specific steps: acquiring the latitude and longitude of a target ship through an automatic ship identification system (AIS); obtaining the distance and orientation of the target ship relative to the ship through a radar; based on the latitude and longitude of the target ship and the distance and orientation of the target ship relative to the ship, obtaining an electronic plotting ship position of the ship; the electronic plotting ship position of the ship and navigation positioning parameters output based on an inertial navigation system (INS) are fused through a volume Kalman filtering algorithm to serve as the ship position after precision enhancement. According to the invention, the electronic plotting ship position of the ship is obtained through AIS information and radar information; and the electronic plotting ship position of the ship is used for performing precision enhancement on the ship position output by the INS, so that the ship position after precision enhancement is obtained. The problem that the positioning precision of an existing INS / GNSS integrated navigation system is reduced due to the fact that measurement data are lost under the condition that the GNSS is interrupted is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ship intelligent navigation autonomous positioning technology, and in particular to a method and system for enhancing ship autonomous positioning in the case of GNSS interruption. Background Art

[0002] In recent years, autonomous surface ships with autonomous navigation capabilities have become an important goal of the development of intelligent ships, which has put forward higher requirements for the accuracy and reliability of ship positioning systems. The combined application of the Global Navigation Satellite System (GNSS) and the Inertial Navigation System (INS) can complement the advantages of INS's short-term high precision and GNSS's long-term stability to improve the accuracy of ship positioning. However, as a radio space positioning technology, GNSS signals are susceptible to environmental interference. In bad weather or sheltered waters, GNSS signals may be interfered or interrupted, resulting in the loss of ship GNSS positioning data. INS errors cannot be effectively suppressed due to cumulative effects, and the reliability of the INS / GNSS combined navigation system is also destroyed, which seriously affects the accuracy and reliability of the ship's navigation and positioning system.

[0003] To solve this problem, existing technologies use deep learning technology to build a pseudo GNSS prediction model to predict missing data when GNSS is interrupted to maintain the continuity of the shipborne INS / GNSS integrated navigation system. However, the prediction error of the deep learning model will increase over time, and its accuracy and reliability can only be maintained for a short period of time, which is difficult to meet the requirements of long-term ship applications.

[0004] Therefore, there is an urgent need for a method that can ensure the ship autonomous positioning capability of the INS / GNSS combined navigation system in the event of a long-term GNSS interruption, and meet the accuracy and reliability requirements of autonomous navigation of autonomous surface ships at sea. Summary of the invention

[0005] In view of this, the present invention provides a method and system for enhancing ship autonomous positioning in the case of GNSS interruption, which solves the problem in the prior art that autonomous surface ships at sea cannot accurately locate themselves in the case of GNSS signal interruption.

[0006] To this end, the present invention provides the following technical solutions:

[0007] A method for enhancing the accuracy of autonomous positioning of a ship in the case of GNSS interruption, comprising:

[0008] Receive AIS information and radar information to obtain the latitude and longitude of the target ship and the distance and direction of the target ship relative to the own ship;

[0009] The electronically plotted position of the own ship is obtained by using the latitude and longitude of the target ship and the distance and bearing of the target ship relative to the own ship;

[0010] The ship's electronically plotted position and the navigation positioning parameters output by the inertial navigation system are integrated to obtain the ship's position with enhanced accuracy.

[0011] Further, the obtaining of the electronically plotted position of the own ship based on the latitude and longitude of the target ship and the distance and azimuth of the target ship relative to the own ship comprises:

[0012] Obtaining the latitude difference and longitude difference between the target ship and the own ship based on the latitude and longitude of the target ship and the distance and azimuth of the target ship relative to the own ship;

[0013] The estimated position of the own ship relative to the target ship is obtained by the latitude difference and longitude difference between the target ship and the own ship;

[0014] When the number of target ships is 1, the estimated position of own ship relative to the target ship is used as the electronically plotted position of own ship;

[0015] When the number of target ships is greater than 1, the estimated position of the own ship relative to each target ship is aggregated through a genetic algorithm to obtain the electronically plotted position of the own ship.

[0016] Further, the latitude difference and longitude difference between the target ship and the own ship are obtained based on the latitude and longitude of the target ship and the distance and azimuth of the target ship relative to the own ship:

[0017]

[0018] In the formula, and is the latitude and longitude of the target ship; and It is the distance and direction of the target ship relative to own ship.

[0019] Furthermore, the estimated position of the own ship relative to the target ship is obtained by using the latitude difference and longitude difference between the target ship and the own ship:

[0020]

[0021] In the formula, is the latitude difference between the target ship and own ship; δλ is the longitude difference between the target ship and own ship.

[0022] Furthermore, the process of aggregating the estimated position of the own ship relative to each target ship by a genetic algorithm to obtain the electronically plotted position of the own ship includes:

[0023] The extreme values ​​of all the estimated positions of the own ship are used as vertex coordinates to construct a two-dimensional plane space;

[0024] Randomly select the initial population in a two-dimensional plane;

[0025] Iterate with the goal of minimizing the fitness function;

[0026] When the preset iteration threshold is reached, the optimal estimated ship position is output as the electronically plotted ship position of the ship.

[0027] Furthermore, the extreme value of the estimated position of the own ship relative to all target ships includes:

[0028] Minimum latitude, maximum latitude, minimum longitude, and maximum longitude.

[0029] Furthermore, the sum of the distances from the optimal estimated ship position to each estimated ship position is used as the fitness function.

[0030] Furthermore, the electronically plotted position of the ship and the navigation positioning parameters output by the inertial navigation system are fused through a volumetric Kalman filter algorithm to obtain the ship position with enhanced accuracy.

[0031] A system for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption, comprising:

[0032] AIS equipment, radar, INS equipment, system server and display interface;

[0033] AIS equipment and radar receive target ship positioning information and transmit it to the system server;

[0034] The INS equipment transmits the navigation and positioning parameters of the ship to the system server;

[0035] The system server performs ship autonomous positioning accuracy enhancement according to the ship autonomous positioning accuracy enhancement method under GNSS interruption conditions according to any one of claims 1 to 8, and outputs the ship position after the accuracy enhancement;

[0036] The target ship positioning information, the own ship's navigation positioning parameters and the ship's position after precision enhancement are visually presented through a display interface.

[0037] Advantages and positive effects of the present invention:

[0038] The present invention obtains the positioning information of the target ship through the ship automatic identification system (Automatic Identification System, AIS) information and radar information, thereby obtaining the electronically plotted ship position of the ship; and uses the electronically plotted ship position of the ship to enhance the accuracy of the ship position output by INS, thereby obtaining the ship position with enhanced accuracy. The problem of reduced positioning accuracy caused by the loss of measurement data in the case of GNSS interruption in the existing INS / GNSS integrated navigation system is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 This is a flow chart of a method for enhancing autonomous positioning of a ship in the event of GNSS interruption in an embodiment of the present invention;

[0041] Figure 2 Schematic diagram of calculating the estimated position of the own ship based on spherical triangles in a single ship encounter scenario in an embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of aggregating multiple estimated positions of the own ship by genetic algorithm in a multi-ship encounter scenario in an embodiment of the present invention;

[0043] Figure 4 It is a framework diagram of a ship autonomous positioning enhancement system under GNSS interruption conditions in an embodiment of the present invention;

[0044] Figure 5 To obtain the target ship positioning information and the electronic plotting position information of the own ship in the scenario where four target ships meet in the embodiment of the present invention;

[0045] Figure 6 It is a schematic diagram of estimating the position of the aggregated own ship in a scenario where four target ships meet in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] The present invention provides a method for ship autonomous positioning in the case of GNSS interruption, which regards the target ship encountered during navigation as a pseudo radar beacon, obtains the electronically plotted ship position of the ship based on the positioning information of the target ship's AIS equipment and the distance and azimuth information of the target ship detected by the ship's radar, and replaces the interrupted GNSS information to input into the INS / GNSS integrated navigation system to enhance the accuracy and reliability of the ship's autonomous positioning. It is achieved to maintain the continuity of the INS integrated navigation system in the case of long-term GNSS interruption, thereby ensuring the ship's autonomous positioning and accuracy enhancement in the case of GNSS interruption.

[0049] Combination Figure 1 The method of the present invention specifically comprises:

[0050] S1: The accelerometer and angular velocity meter outputs of the ship are measured by the inertial navigation system during navigation, and the navigation and positioning parameters of the ship are updated based on the INS navigation and positioning parameter update algorithm, including the ship attitude matrix. Velocity Vector Position vector (p INS ), and own ship at sea Figure 2 Dead reckoning of ship position by INS on a 3D plane

[0051] S11. Use the angular velocity meter in the INS to measure the angular velocity of the ship carrier coordinate system relative to the inertial coordinate system. And the specific force information (f b );

[0052] S12. Obtain the navigation and positioning parameters of the ship based on INS calculation based on the INS navigation and positioning parameter update algorithm. The INS navigation and positioning parameter update algorithm is mainly derived based on the differential equations of attitude, velocity and position:

[0053]

[0054] In the formula, is the attitude matrix of own ship, is the projection component of the ship's velocity in the navigation coordinate system, p INS is the position vector of the ship, which is determined by the geographic latitude Geographic longitude and altitude composition.

[0055] Own ship position vector and For this ship at sea Figure 2 Dead reckoning of ship position by INS on a 3D plane The coordinate value of

[0056] S2: Use the AIS equipment of the ship to receive the AIS position information released by the target ship encountered during the voyage; at the same time, based on the distance and direction of the target ship detected by the radar of the ship, obtain the electronically plotted ship position.

[0057] According to the number of target ships to be encountered, the electronically plotted ship position includes two situations:

[0058] If the number of target ships is 1, the calculated position is the electronically plotted position of the ship P TS ;

[0059] The number of target ships is greater than 1, and each encountering ship will get a calculated position (P TSi ), using genetic algorithm to transform multiple P TSi Aggregate and obtain the optimal estimated ship position as the electronically plotted ship position P of the ship TS .

[0060] S21, Single-ship encounter scenario

[0061] AIS equipment mainly transmits and receives signals based on VHF antennas. Its coverage range is generally within 30-50 nautical miles, which is a very small range compared to the radius of the earth. Therefore, when calculating the ship's estimated position, the earth is assumed to be a sphere. Figure 2 shown.

[0062] The ship is located at Figure 2 (a) shows point A on the earth. The target ship is located at point B on the earth. The latitude and longitude of point B are obtained through the AIS equipment: Get the distance between point B and point A through radar and direction

[0063] use Calculate the estimated position of the ship at point A

[0064] On the earth's sphere, the own ship and the target ship together form a spherical triangle p n AB. In the spherical triangle p n In AB, p n Point A' on A is on the same meridian as point A and on the same equal latitude circle as point B. Since the longitude and latitude of point B can be obtained through AIS, the latitude difference between points A and B is calculated. The estimated position of the ship can be obtained by the difference in longitude (δλ).

[0065] Calculate the latitude difference between point A and point B

[0066] It is the difference in arc between the two equal latitude circles where points A and B are located, which is regarded as the difference in arc between two points on the earth's surface along the meridian direction. Figure 2 (a) A'A is the corresponding

[0067] In the spherical triangle p n AB intercepts the non-standard spherical triangle A'AB. Since the non-standard spherical triangle A'AB covers a small area, it can be positioned as an approximate right triangle, such as Figure 2 (b). At this time, the length of A'A is:

[0068]

[0069] Since AB is on a great circle on the surface of the earth, the length of AB can be calculated from the distance between points A and B. And the radius of the earth (R) is calculated, that is:

[0070]

[0071] In summary, the latitude difference between points A and B is:

[0072]

[0073] Calculation of the longitude difference (δλ) between point A and point B:

[0074] δλ corresponds to the length of the arc between the meridians of points A and B on the equator, corresponding to Figure 2 A in (a) q B q . Due to A q B q Cannot be used with d B and C B Establish direct contact, but A q B q The corresponding central angle (∠A q O g Bq ) and the central angle (∠A'O g 'B) are the same, so the following relationship can be established:

[0075]

[0076] Based on formula (5), we can get:

[0077]

[0078] In the nonstandard spherical triangle A'AB:

[0079]

[0080] Combining formula (7) and formula (8) we can get δλ:

[0081]

[0082] Based on the target ship at point B, the estimated position of the own ship is obtained, such as Figure 2 (c) as shown:

[0083]

[0084] The electronically plotted position obtained based on the target ship at point B is the electronically plotted position of this ship.

[0085] S22, Multiple Ships Encounter Scene

[0086] For multi-ship encounter scenarios, each target ship will have a target ship i (i = 1, 2, 3, ..., n) position information published by AIS. And the distance between the target ship i detected by the radar and the ship and direction

[0087] The estimated positions of n own ships are obtained by formula (10):

[0088] In the process of obtaining the target ship's positioning information, the AIS information is based on the installation position of its antenna, and the radar detection information tests the distance and direction of the target ship's closest cross section from the ship. The position references of the radar and AIS are not in the same position, so the calculation based on different target ships cannot be located in the same position, so the genetic algorithm is used to separate the scattered Aggregate into one electronically plotted position like Figure 3 As shown:

[0089] In multiple The extreme value of the electronically plotted position of the ship in the screening, that is, the minimum latitude Maximum latitude Minimum longitude Maximum longitude

[0090] Perform genetic algorithm population initialization operation. The two-dimensional space of the chart plane determined by these four vertices Randomly initialize 20 possible optimal estimated positions of the ship within the range As the initial population for genetic operations.

[0091] Calculated using the Haversine formula To each The distance (d TSi ):

[0092]

[0093] Construct a fitness function for genetic operations. To each The sum of the distances is used as a fitness function

[0094]

[0095] Set the maximum number of iterations of genetic operation to 50 times, and in each iteration step, the fitness function The target is to minimize the number of populations, perform selection, crossover and mutation operations on the population, and output the optimal estimated ship position after reaching the maximum iteration step of 50 times. The best estimated ship position shall be used as the electronically plotted ship position of the ship.

[0096] S3: The obtained electronically plotted position of own ship (P TS ) is used as the alternative GNSS position information during the GNSS outage, and the cubature Kalman filter is used to fuse the navigation positioning parameters output by the INS equipment to obtain the ship position after accuracy enhancement (P A ).

[0097] S31. Construct the integrated navigation system equation based on formula (1):

[0098]

[0099] In the formula, x(t) is composed of the attitude error (φ), velocity error Position error (δp INS ), gyroscope random constant drift (ε b ), random constant drift of acceleration The 15-dimensional state vector is composed of these two together; F(t) is the transfer matrix of the state equation; G(t) is the noise driving matrix; is the system noise, which is a Gaussian white noise with a mean of 0 and a variance of Q.

[0100] S32, using the electronically plotted position of the own ship obtained in step S2 The ship position output by INS Construct the measurement equation:

[0101]

[0102] Where υ(t) is the measurement noise, which is composed of radar measurement error, AIS error, error caused by the inconsistency of radar and AIS coordinate systems, and rounding error caused in the calculation process. In the calculation process, it is assumed to have a mean of 0 and a variance of R. k Gaussian white noise.

[0103] S33, using the volumetric Kalman filter algorithm, the constructed system equation and the measurement equation are fused, and the electronic plotting position of the ship (P TS ) for the ship position (P) output by INS INS ) to enhance the accuracy, and then obtain the ship position P after the accuracy enhancement A By introducing the electronic plotting position of the ship (P TS ) makes up for the problem of measurement data loss in the INS / GNSS integrated navigation system in the event of GNSS interruption.

[0104] The present invention also includes a system for enhancing the autonomous positioning of ships under GNSS interruption conditions, which integrates the constructed method for enhancing the autonomous positioning of ships under GNSS interruption conditions to realize the visualization of the target ship radar information, AIS information, the INS navigation positioning parameters of the ship, the electronically plotted ship position of the ship, and the ship position after accuracy enhancement.

[0105] Combination Figure 4 The ship autonomous positioning enhancement system under the GNSS interruption condition of the present invention comprises:

[0106] AIS equipment, radar, INS equipment, system server and display interface;

[0107] AIS equipment and radar receive target ship positioning information and transmit it to the system server;

[0108] The INS equipment transmits the navigation and positioning parameters of the ship to the system server;

[0109] The system server enhances the ship's autonomous positioning accuracy according to the ship's autonomous positioning accuracy enhancement method under GNSS interruption conditions, and outputs the ship's position after the accuracy enhancement;

[0110] The target ship positioning information, the own ship's navigation positioning parameters and the ship's position after precision enhancement are visualized through the display interface.

[0111] The display interface includes: (1) radar information display module: used to display radar target detection images; (2) INS equipment information display module: used to display the navigation positioning parameters of the ship obtained based on the INS equipment (3) Electronically plotted position display module for own ship: used to display radar and AIS information of different targets (TSi), and the electronically plotted position of own ship calculated based on different TSi And the electronically plotted position of the ship after aggregation by genetic algorithm (4) After the accuracy is enhanced, the ship position display module is used to display and The ship position after fusion with enhanced accuracy (P A ).

[0112] Combination Figure 5 The method of the present invention is further described with the following application examples:

[0113] The ship is in a navigation scenario where it will meet four target ships. At this time, the GNSS signal of the ship is interrupted. The ship positioning information based on GNSS (P GNSS ) is lost, the ship performs autonomous positioning based on the ship autonomous positioning enhancement under GNSS interruption:

[0114] The INS equipment installed on the ship is used to measure the output of the accelerometer and angular velocity meter during the navigation process of the ship. Then, based on the INS navigation parameter update algorithm, the navigation parameters of the ship calculated based on the INS are obtained, including the ship attitude matrix. Velocity Vector Position vector (p INS ), and own ship at sea Figure 2 Dead reckoning of ship position by INS on a 3D plane Will p INS as well as Input to Figure 4 The constructed ship autonomous positioning enhancement system includes p INS Input into the system equation constructed by formula (13) to prepare for the subsequent acquisition of the electronically plotted position of the ship Then perform data fusion; Then transfer to Figure 4The INS information display module of the constructed ship autonomous positioning augmentation system in the event of GNSS interruption.

[0115] First, use AIS equipment and radar to obtain the location of each target distance and location information like Figure 5 Then, the four dead reckoning positions of the own ship based on the information of four different target ships are calculated using formula (10): Since the position references used by AIS and radar of different target ships are not necessarily the same, and there are errors in the calculation process, the four electronic dead reckoning positions of the ship are Not necessarily at the same location, but may be distributed at the optimal electronically plotted position around, such as Figure 6 As shown, at this time, the optimal electronic optimal ship position aggregation algorithm based on the genetic algorithm constructed above is further applied to obtain the optimal electronic plotted ship position of the own ship. and will Input to formula (14) Construct the measurement equation. The as well as Will be transferred to Figure 4 The electronically plotted ship position display module of the ship autonomous positioning enhancement system constructed in the case of GNSS interruption.

[0116] The cubature Kalman filter algorithm is used to fuse the constructed system equation and the measurement equation to obtain the ship position after precision enhancement (P A ), to achieve autonomous positioning of the ship without GNSS information. A Transfer to Figure 4 The ship position display module after the accuracy enhancement of the ship's autonomous positioning enhancement system in the case of GNSS interruption is shown. Radar information is transmitted to the radar information display module; the navigation positioning parameters of the ship obtained based on the INS equipment Transmitted to the INS equipment information display module; radar and AIS information of different targets (TSi), electronically plotted position of own ship calculated based on different TSi And the electronically plotted position of the ship after aggregation by genetic algorithm Transmitted to the electronic plotting position display module of the ship.

[0117] The method of the present invention can provide ship positioning information for the INS / GNSS integrated navigation system in the case of GNSS interruption, thereby solving the problem that the INS navigation error caused by GNSS interruption in the INS / GNSS integrated navigation system cannot be effectively suppressed due to the cumulative effect, thereby destroying the reliability.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption, characterized in that: include: Receive AIS information and radar information to obtain the latitude and longitude of the target ship and the distance and direction of the target ship relative to the own ship; The electronically plotted position of the own ship is obtained by using the latitude and longitude of the target ship and the distance and bearing of the target ship relative to the own ship; The ship's position after accuracy enhancement is obtained by integrating the ship's electronically plotted position and the navigation positioning parameters output by the inertial navigation system.

2. According to the method for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption in claim 1, it is characterized in that: The step of obtaining the electronically plotted position of the own ship based on the latitude and longitude of the target ship and the distance and azimuth of the target ship relative to the own ship comprises: Obtaining the latitude difference and longitude difference between the target ship and the own ship based on the latitude and longitude of the target ship and the distance and azimuth of the target ship relative to the own ship; The estimated position of the own ship relative to the target ship is obtained by the latitude difference and longitude difference between the target ship and the own ship; When the number of target ships is 1, the estimated position of own ship relative to the target ship is used as the electronically plotted position of own ship; When the number of target ships is greater than 1, the estimated position of the own ship relative to each target ship is aggregated through a genetic algorithm to obtain the electronically plotted position of the own ship.

3. According to claim 2, a method for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption, characterized in that: The latitude difference and longitude difference between the target ship and the own ship are obtained based on the latitude and longitude of the target ship and the distance and azimuth of the target ship relative to the own ship: In the formula, and is the latitude and longitude of the target ship; and It is the distance and direction of the target ship relative to own ship.

4. According to claim 3, a method for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption is characterized in that: The estimated position of the own ship relative to the target ship is obtained by the latitude difference and longitude difference between the target ship and the own ship: In the formula, is the latitude difference between the target ship and own ship; δλ is the longitude difference between the target ship and own ship.

5. According to claim 2, a method for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption, characterized in that: The method of aggregating the estimated position of the own ship relative to each target ship by using a genetic algorithm to obtain the electronically plotted position of the own ship includes: The extreme values ​​of all the estimated positions of the own ship are used as vertex coordinates to construct a two-dimensional plane space; Randomly select the initial population in a two-dimensional plane; Iterate with the goal of minimizing the fitness function; When the preset iteration threshold is reached, the optimal estimated ship position is output as the electronically plotted ship position of the ship.

6. According to claim 5, a method for enhancing the accuracy of autonomous ship positioning in the case of GNSS interruption is characterized in that: The extreme value of the estimated position of the own ship relative to all target ships includes: Minimum latitude, maximum latitude, minimum longitude, and maximum longitude.

7. According to claim 5, a method for enhancing the accuracy of autonomous ship positioning in the case of GNSS interruption is characterized in that: The sum of the distances from the optimal estimated ship position to each estimated ship position is taken as the fitness function.

8. According to the method for enhancing the accuracy of ship autonomous positioning in the case of GNSS interruption in claim 1, it is characterized in that: The electronically plotted ship position of the ship and the navigation positioning parameters output by the inertial navigation system are fused through the cubature Kalman filter algorithm to obtain the ship position with enhanced accuracy.

9. A system for enhancing the accuracy of ship autonomous positioning in the event of GNSS interruption, characterized in that: include: AIS equipment, radar, INS equipment, system server and display interface; AIS equipment and radar receive target ship positioning information and transmit it to the system server; The INS equipment transmits the navigation and positioning parameters of the ship to the system server; The system server performs ship autonomous positioning accuracy enhancement according to the ship autonomous positioning accuracy enhancement method under GNSS interruption conditions according to any one of claims 1 to 8, and outputs the ship position after the accuracy enhancement; The target ship positioning information, the own ship's navigation positioning parameters and the ship's position after precision enhancement are visually presented through a display interface.

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