A Ship Ultra-High Collision Bridge Warning Method Based on Differential GNSS Technology

Abstract

The present invention discloses a method for warning of ships' ultra-high collision with bridges based on differential GNSS technology, which comprises the following steps: S1) performing static and accurate elevation measurement on bridges based on differential GNSS to obtain the elevation of each bridge; S2) performing dynamic and accurate elevation measurement on ships based on differential GNSS; S3) when navigating to the bridge area waters, comparing the ship's elevation at this time with the elevation of the bridge that has been measured before to determine whether the ship can safely pass through the bridge. The method for warning of ships' ultra-high collision with bridges based on differential GNSS technology provided by the present invention can accurately calculate the elevation of the bridge opening and the ship, improve the measurement accuracy, better meet the warning requirements for ships' ultra-high collision with bridges, and greatly improve the safety of ship navigation.

Description

Technical Field

[0001] The present invention relates to a warning method for a ship with an ultra-high collision risk against a bridge, and particularly to a warning method for a ship with an ultra-high collision risk against a bridge based on differential GNSS technology. Background Art

[0002] The Global Navigation Satellite System (GNSS) technology can provide users with accurate and continuous three-dimensional position and velocity information and is the most commonly used positioning method. It has the advantages of all-weather, global coverage, high precision, and real-time monitoring. With the rapid development of the economy and technology, GNSS positioning technology and systems are constantly updated and iterated, and have gone through stages such as Doppler positioning, pseudo-range single-point positioning, pseudo-range differential positioning, carrier-phase differential positioning (RTK), precise point positioning (PPP), regional RTK (network RTK), and wide-area RTK (PPP-RTK). Among them, the real-time carrier-phase differential (RTK) in phase differential has reached the centimeter level. Now, in the fields of deformation monitoring, control surveying, urban planning, topographic mapping, etc., the carrier-phase differential (RTK) technology has been widely used, making people's lives more convenient and efficient. Currently, not only the GPS positioning system in the United States is under construction, but also the GLONASS system in Russia, the Galileo system in Europe, and the Beidou Navigation Satellite System independently developed and designed in China.

[0003] At present, the continuously operating satellite positioning reference station system CORS (Continuously Operating Reference Stations) based on multi-base network RTK technology has been applied in various industries as a more accurate and convenient service. China's CORS system mainly adopts a multi-integration networking mode jointly responsible by multiple units and industries, realizing the reasonable sharing of resources. The Beidou CORS system can be defined as one or more fixed and continuously operating reference stations of Beidou, a network composed of modern computers, data communication, and Internet (LAN / WAN) technologies, which can automatically provide various correction signals, status information, etc. related to the Beidou Navigation Satellite System for users of different types, requirements, and levels in real-time and pseudo-range, including the observations (carrier phase) of the Beidou Navigation Satellite System. The CORS system shortens the initialization time, expands the measurement range, and completely changes the traditional operation mode.

[0004] Bridge collisions caused by the excessive height of ships occur frequently. Therefore, there is an urgent need for a method that can effectively determine whether a ship can pass under a bridge safely. Some scholars have studied using the method of taking photos and identifying the depth of field to calculate whether a ship can pass under a bridge safely, and some scholars have studied using the method of combining radar and GPS to determine whether a ship can pass under a bridge safely. However, the existing methods have problems such as low accuracy, limited detection range, and susceptibility to weather conditions. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a warning method for ship's excessive height collision with bridges based on differential GNSS technology, which can accurately calculate the elevations of bridge openings and ships, improve the measurement accuracy, better meet the warning requirements for ship's excessive height collision with bridges, and greatly improve the safety of ship navigation.

[0006] The technical solution adopted by the present invention to solve the above technical problem is to provide a warning method for ship's excessive height collision with bridges based on differential GNSS technology, including the following steps: S1) Based on differential GNSS, perform static and accurate elevation measurement on the bridge to obtain the elevation of each bridge; S2) Based on differential GNSS, perform dynamic and accurate elevation measurement on the ship; S3) When navigating to the bridge area waters, compare the ship's elevation at this time with the elevation of the bridge that has been measured before to determine whether the ship can pass under the bridge safely.

[0007] In the above warning method for ship's excessive height collision with bridges based on differential GNSS technology, in step S1, 3 measurement points are taken for each bridge opening, namely the highest point and two lowest points of the bridge opening. Subtract the distance h from the elevation of the bridge measured at the highest point of the bridge opening to the highest point of the bridge opening 1 , and the elevation values h of the bridge opening are obtained respectively 高 =h 测 -h 1 , h 低 =h 测 -h 2 , h 2 is the distance from the bridge deck to the safe protection distance of the bridge pier of the bridge opening. Subtract the elevation of the lowest point from the elevation of the highest point of the bridge opening to obtain h 差 =h 高 -h 低 , ε=h 差 / 2.

[0008] In the above warning method for ship's excessive height collision with bridges based on differential GNSS technology, in step S1, the CORS system based on carrier phase differential is used to measure the same measurement point multiple times, and the static measurement data is analyzed through internal consistency accuracy and external consistency accuracy to control the error within the centimeter level.

[0009] The above ship ultra-high collision bridge warning method based on differential GNSS technology, wherein in step S2, the elevation of the ship is obtained in real time through differential positioning, and the measured elevation of the ship is added to the distance h from the measuring device to the highest point of the ship 3 , to obtain the elevation value h of the ship 船 =h 测 +h 3 .

[0010] The above ship ultra-high collision bridge warning method based on differential GNSS technology, wherein in step S2, two sets of data in the ship's moored state and sailing state are obtained respectively, and the internal consistency accuracy and the dynamic positioning accuracy method based on the fitting trajectory deviation are used for the dynamic measurement to analyze and control the error to be kept at the decimeter level.

[0011] The above ship ultra-high collision bridge warning method based on differential GNSS technology, wherein in step S2, according to the elevation data of the ship at berth and the elevation data of the ship during navigation, fitting lines are established respectively, the distances between the measured points and the points on the fitting lines are obtained, and the mean square error of the dynamic data is calculated.

[0012] The above ship ultra-high collision bridge warning method based on differential GNSS technology, wherein in step S2, the total least squares model is used for fitting the line:

[0013] The straight line equation is expressed as:

[0014] y=ax + b

[0015] where x and y are variables, and a and b are equation coefficients;

[0016] The error equation is expressed as:

[0017]

[0018] where v y =[v y1 v y2 v y3 …v yn T , x=[x 1 x 2 x 3 …x n T , y=[y 1 y 2 y 3 …y n T ;

[0019] It is transformed into the following matrix form

[0020] ​​​V = AX - L

[0021] Wherein, V is the error matrix, A is the coefficient matrix, and L is the observed quantity;

[0022] The constraint condition is expressed as:

[0023]

[0024] The least squares solution is obtained as:

[0025] X = (A T A) -1 A T .

[0026] In the above ship ultra-high collision bridge warning method based on differential GNSS technology, in step S1, the elevation of the bridge is accurately measured statically by the positioning module BT-F9PK2, and the static measurement data controls the error within 1 cm through the analysis of the internal compliance accuracy and the external compliance accuracy. In step S2, the Beidou-RTK differential positioning of the ship is carried out by the positioning module BT-F9PK2 and the high-precision helical antenna to obtain the elevation of the ship in real time. The measurement error is controlled within 6 cm when the ship is berthed, within 45 cm when the ship just starts, and within 16 cm during stable navigation.

[0027] In the above ship ultra-high collision bridge warning method based on differential GNSS technology, assuming that α is the safety height margin between the ship and the bridge, step S3 includes:

[0028] When h 船 < h 低 -, it is determined that the ship can pass the bridge safely. When h 低 - ≤ h 船 < h 高 -, a reminder warning message for driving in the middle is provided. When h 高 - ≤ h 船 < h 高 -, a dangerous signal of possible ship-bridge collision is provided to remind driving in the middle. When h 高 - ≤ h 船 , it is considered that the ship cannot pass the bridge.

[0029] The present invention has the following beneficial effects compared with the prior art: The ship ultra-high collision bridge warning method based on differential GNSS technology provided by the present invention measures the elevations of the ship and the bridge through the differential Beidou navigation satellite system positioning technology, thereby effectively calculating the elevations of the bridge opening and the ship, improving the measurement accuracy, and preferably meeting the warning requirements for ships with ultra-high collision bridges. By comparing the elevations of the ship and the bridge and conducting continuous dynamic measurement and analysis during the passage of the ship, the longitudinal space of the ship passing through the bridge can be measured in real time, and four situations are used to provide ship ultra-high warning for the crew, ensuring the safety and smoothness of inland river navigation. This is of great significance for improving water traffic safety at home and abroad and greatly improves the safety of ship navigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram for measuring the elevation value of the bridge opening of the present invention;

[0031] Figure 2 It is a schematic diagram for measuring the elevation value of the ship of the present invention;

[0032] Figure 3 It is a schematic diagram for anti-collision of bridge and ship elevation measurement of the present invention;

[0033] Figure 4 It is a flow chart for anti-collision of bridge and ship elevation measurement of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The following further describes the present invention in conjunction with the drawings and embodiments.

[0035] The ship ultra-high collision bridge warning method based on differential GNSS technology provided by the present invention includes the following steps:

[0036] S1: Adopt the centimeter-level positioning module BT-F9PK2 of Qianxun Positioning Co., Ltd., and conduct precise static elevation measurement on the bridge and precise dynamic elevation measurement on the ship through the Qianxun CORS (Continuously Operating Reference Stations) network provided by Qianxun Positioning Co., Ltd. When conducting differential measurement of the static real-time kinematic Beidou-RTK (Real Time Kinematic) technology on the bridge, the measured data is the height h from the bridge deck to the reference ellipsoid P. 测 , Take 3 measurement points for the bridge opening respectively, take the highest point and two lowest points of the bridge opening, and subtract the distance h from the bridge deck to the highest point of the bridge opening from the bridge elevation measured at the highest point of the bridge opening. 1 , h 2 is the distance from the bridge deck to the distance L of the safety protection distance of the pier of the bridge opening, and the elevation value h of the bridge opening is obtained respectively. 高 = h 测 - h 1 , h低 =h 测 -h 2 .

[0037] S2: When performing differential measurement of the ship using the dynamic Beidou Navigation Satellite System-RTK technology, the measured data is the height h from the measuring equipment to the reference ellipsoid P. 测 Since the measuring equipment cannot be installed at the highest part of the ship, the measured ship elevation plus the distance h from the measuring equipment to the highest point of the ship is 3 , get the ship's elevation h 船 =h 测 +h 3 , the principle is as follows Figure 1 , Figure 2 shown.

[0038] S3: Perform error analysis on the obtained bridge and ship elevation data. When the bridge elevation measurement error is kept at the centimeter level and the ship elevation error is kept at the decimeter level, the difference between the highest and lowest points of the bridge hole can be obtained to obtain h 差 =h 高 -h 低 , ε=h 差 / 2.

[0039] The step S3 comprises:

[0040] This test uses the CORS system based on carrier phase differential (RTK) technology to measure the same point 6 times to obtain the average level of the measured point in the elevation direction, and calculates the distance deviation between the data and the average level in the elevation direction. The internal accuracy expression is:

[0041]

[0042] Among them, Δ is the distance deviation between the measured data and the average level of the measured value, n is the total number of data obtained in each measurement, and M is the internal accuracy.

[0043] External accuracy is the deviation between the measured data and the known value. The calculation formula is shown in formula (5-2):

[0044]

[0045] Among them, θ is the external accuracy, δ i is the measured value of the i-th point, τ i is the known value of the i-th point, and N is the number of data actually measured.

[0046] Analysis of dynamic positioning accuracy method based on fitting trajectory deviation: The methods for precision measurement include mean square error, average error, etc. Mean square error is a numerical standard used to measure the accuracy of observations, also known as "standard deviation" or "root mean square error". Since the true error cannot be accurately obtained, the correction of the observed value obtained by the least squares method is usually used to replace the true error. Mean square error is the square root of the ratio of the sum of the squares of the deviations between the observed values and the true values to the number of observations n.

[0047]

[0048] Among them, M is the measurement mean square error. In the general process of dynamic positioning accuracy analysis, when calculating the mean square error, x i is the deviation between the measured value and the true value, and n is the number of observations. The distance between the measuring point and the point on the fitting curve or straight line at the same time series is used as the deviation between the measured value and the true value and substituted into the error calculation formula to obtain the mean square error of the measurement data, and then analyze the real-time dynamic measurement positioning accuracy.

[0049] In the linear fitting model, since the least squares algorithm only considers the error caused by one variable, while the total least squares algorithm considers both the variable and the error of the coefficient matrix, using the total least squares model for linear fitting is more in line with the actual trajectory.

[0050] The linear equation is expressed as:

[0051] y = ax + b (5-4)

[0052] In the formula, x and y are variables, and a and b are the coefficients of the equation.

[0053] The error equation can be expressed as:

[0054]

[0055] Among them, v y = [v y1 v y2 v y3 …v yn T , x = [x 1 x 2 x 3 …x n T , y = [y 1 y 2 y 3 …y n T .

[0056] Then the matrix form of formula (5-5) is

[0057] V = AX - L (5-6)

[0058] Wherein, V is the error matrix, A is the coefficient matrix, and L is the observed quantity.

[0059] The constraint condition can be expressed as:

[0060]

[0061] Therefore, its least squares solution is:

[0062] X = (A T A) -1 A T (5-8)

[0063] According to the elevation data of the ship at berth and the elevation data of the ship during navigation, fitting lines are established respectively, the distances between the measurement points and the points on the fitting lines are obtained, and the mean square error of the dynamic data is calculated.

[0064] Elevation measurements and analyses were carried out on the test points, bridges and ships. First, static measurements were carried out: the test points were measured 6 times, and the internal consistency accuracy and external consistency accuracy of the measurement data were analyzed, with the accuracy within 1 cm. Static measurements were carried out on the three bridges respectively and the internal consistency accuracy was analyzed. Then dynamic measurements were carried out: during the passage of the ship, dynamic elevation measurements were carried out on the ship, and the internal consistency accuracy and the dynamic positioning accuracy method based on the fitting trajectory deviation of the measurement data were analyzed respectively.

[0065] S4: Assume that α is the safety height margin between the ship and the bridge, h 船 < h 低 - When this is the case, the present invention believes that the ship can pass through the bridge safely. When h 低 - ≤ h 船 < h 高 - When this is the case, the system automatically generates a warning and timely provides the crew with a reminder warning message to drive in the middle. When h 高 - ≤ h 船 < h 高 - When this is the case, the risk of ship-bridge collision is relatively large, the system automatically generates a warning, and timely provides the crew with a dangerous signal that a ship-bridge collision may occur, reminding the crew to drive in the middle. When h 高 - ≤ h 船 When this is the case, the present invention believes that the ship cannot pass through the bridge. At this time, a ship over-height warning message is sent to the crew, and the ship can stop nearby and wait for the water level to drop before passing through the bridge. Therefore, the present invention can intuitively know whether the ship can pass through the bridge safely. As Figure 3 shown, the test process is as Figure 4 shown.

[0066] The present invention proposes a new method for measuring the elevations of ships and bridges based on the differential Beidou Navigation Satellite System - RTK technology, which can play an important role in the safe navigation of ships. When a ship is sailing, the Beidou - RTK differential positioning of the ship can be obtained in real time through the positioning module BT - F9PK2 and the high - precision helical antenna to obtain the elevation of the ship. It is not necessary to build a base station for RTK precise differential positioning, and the accuracy can reach the centimeter level. This method directly measures the heights of the ship and the bridge, thereby effectively calculating the elevations of the bridge opening and the ship, improving the measurement accuracy. When navigating to the bridge area waters, comparing the elevation of the ship at this time with the highest and lowest elevations of the bridge that have been measured before can visually determine whether the ship can safely pass through the bridge, and it has good practicability. It is divided into four situations, respectively providing warnings for the driver that it can pass safely, drive in the middle, there is a greater risk of ship - bridge collision and drive in the middle, and cannot pass, which better meets the warning requirements for ships with excessive height colliding with bridges.

[0067] The present invention measures three bridges, namely the Dazhi River Bridge on the Hangnan Highway, the Overhead Bridge on the Zhahang Road, and the Dazhi River Bridge. Five points of each bridge are measured respectively by the present invention. Through the analysis of the internal consistency accuracy and the external consistency accuracy of the static measurement data, the error can be obtained within 1 cm, and the elevation of each bridge can be obtained. Long - term measurements are carried out on the Shanghai - Ring solid waste container ship "Hu Huanyun Cargo 6006". Two groups of data in the moored state and the sailing state are obtained. The internal consistency accuracy and the dynamic positioning accuracy method based on the fitting trajectory deviation are respectively analyzed for the dynamic measurement. It can be obtained that the measurement error is within 6 cm when the ship is moored, within 45 cm when the ship just starts, and within 16 cm when the ship is sailing stably, which can better meet the warning requirements for ships with excessive height colliding with bridges, and the elevation of the ship can be obtained. Therefore, the present invention can visually know whether the ship can safely pass through the bridge. After analysis, it can be obtained that there is no problem for the ship to pass through the bridge under normal circumstances. In the case of high tide or heavy rain, the elevation can be measured by this method. This method can visually show the difference in elevation between the bridge and the ship, and can very intuitively know whether the ship can safely pass through the bridge, greatly improving the safety of ship navigation and having good practicability at the same time.

[0068] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the claims.

Claims

1. A method for warning of ships' ultra-high collision with bridges based on differential GNSS technology, characterized in that, it includes the following steps: S1) Based on differential GNSS, perform static and precise elevation measurement on bridges to obtain the elevation of each bridge; S2) Based on differential GNSS, perform dynamic and precise elevation measurement on ships; S3) When navigating to the bridge area waters, compare the ship's elevation at this time with the elevation of the bridge that has been measured before to determine whether the ship can safely pass the bridge; In step S1, three measurement points are taken for the bridge opening of each bridge, namely the highest point and the two lowest points of the bridge opening. The bridge elevation measured at the highest point of the bridge opening is subtracted by the distance h from the bridge deck to the highest point of the bridge opening 1 , and the elevation values of the bridge opening are obtained respectively = - h 1 , = - h 2 , h 2 is the distance from the bridge deck to the distance of the safety protection distance of the bridge pier of the bridge opening. Taking the difference between the elevations of the highest point and the lowest point of the bridge opening, we can get ; In step S1, a CORS system based on carrier phase difference is used to measure the same measurement point multiple times, and the static measurement data is analyzed through internal consistency accuracy and external consistency accuracy to control the error within the centimeter level; In step S2, the elevation of the ship is obtained in real time through differential positioning, and the measured elevation of the ship is added to the distance h from the measuring device to the highest point of the ship 3 , to obtain the elevation value of the ship = + h 3 ; In step S2, two groups of data in the ship's moored state and sailing state are obtained respectively, and the internal consistency accuracy and the dynamic positioning accuracy method based on the fitting trajectory deviation are used to analyze and control the error within the decimeter level for the dynamic measurement; In step S2, according to the elevation data of the ship at berth and the elevation data of the ship during navigation, fitting lines are established respectively, the distance between the measurement point and the point on the fitting line is obtained, and the mean square error of the dynamic data is calculated; In step S1, the elevation of the bridge is statically and precisely measured by the positioning module BT-F9PK2, and the static measurement data is analyzed through internal consistency accuracy and external consistency accuracy to control the error within 1 cm. In step S2, the Beidou-RTK differential positioning is used by the positioning module BT-F9PK2 and the high-precision helical antenna to obtain the elevation of the ship in real time, and the measurement error is controlled within 6 cm when the ship is at berth, within 45 cm when the ship just starts, and within 16 cm during stable navigation; Hypothesis is the safety height margin between the ship and the bridge, and the step S3 includes: When it is determined that the ship can safely pass through the bridge. When it is, a reminder warning message for driving in the middle is provided. When it is, a danger signal of possible ship-bridge collision is provided to remind driving in the middle. When it is, it is considered that the ship cannot pass through the bridge.

2. The method for warning of ships' ultra-high collision with bridges based on differential GNSS technology according to claim 1, characterized in that, in step S2, the total least squares model is used for the fitting of the straight line: The straight line equation is expressed as: In the formula, x , y are variables, a, b are equation coefficients; The error equation is expressed as: Among them, , , ; It is transformed into the following matrix form In the formula, V is the error matrix, A is the coefficient matrix, and L is the observable; The constraint condition is expressed as: The least squares solution is obtained as:

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