Beidou inertial combination rapid measurement system and method for large-scale bridge line shape

Abstract

The invention relates to a big dipper inertial combination rapid measurement system and method for a large-scale bridge line shape, and belongs to the technical field of bridge measurement, the big dipper inertial combination rapid measurement system for the large-scale bridge line shape comprises a measurement unit, the three-axis acceleration sensor is used for measuring the three-axis acceleration, the three-dimensional angular velocity vector, the absolute position coordinate, the forward speed and the height from a chassis to a bridge floor of the measuring vehicle; the data acquisition unit is used for synchronously recording and storing measurement data of the measurement unit according to a time sequence; and the data processing unit is used for carrying out bridge linear measurement based on the measurement data stored in the data acquisition unit. According to the invention, not only is the measurement efficiency ensured, but also the measurement precision is ensured while the elevation measurement of the bridge is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge measurement, and in particular to a Beidou inertial combination rapid measurement system and method for the linear shape of a large bridge. Background Art

[0002] Large bridges are important transportation infrastructure and play an important role in economic and social development. During the long-term service of large bridges, their bearing capacity, safety and durability will gradually fail to meet operational requirements, and even disasters and accidents may occur. Therefore, it is very important to carry out structural health monitoring and assessment.

[0003] The bridge alignment can directly invert the internal force changes of its structure under the combined action of various loads, and is an important technical content of bridge structure health monitoring. Due to the large span of large bridges, the main factors affecting their alignment include ambient temperature, load, etc. Therefore, the measurement of their alignment needs to take into account both accuracy and efficiency to ensure that the impact of ambient temperature is minimized.

[0004] Existing bridge linear measurement methods often fail to strike a balance between accuracy and efficiency, which results in unsatisfactory measurement results. Therefore, how to strike a balance between accuracy and efficiency in the bridge linear measurement process has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, it is necessary to provide a Beidou inertial combination rapid measurement system and method for the linear shape of large bridges to solve the problem that existing bridge linear shape measurement methods often find it difficult to balance accuracy and efficiency, which leads to unsatisfactory measurement results.

[0006] In order to solve the above problems, the present invention provides a Beidou inertial combination rapid measurement system for the linear shape of a large bridge, comprising: The measuring unit is used to measure the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and height of the chassis from the bridge deck of the measuring vehicle; A data acquisition unit, used to synchronously record and store the measurement data of the measurement unit in chronological order; The data processing unit is used to perform linear measurement of the bridge based on the measurement data stored in the data acquisition unit.

[0007] In a possible implementation, the measuring unit includes: A survey vehicle, an inertial measurement unit, a GNSS receiver and antenna, a displacement sensor and a prism rigidly fixed on a mounting bracket of the survey vehicle, an odometer rigidly fixed on wheels of the survey vehicle, and a total station set at preset control points at the starting point and the end point of the target bridge.

[0008] In a possible implementation, the inertial measurement unit includes a three-axis accelerometer and a three-axis gyroscope, which are used to measure the three-axis acceleration and three-dimensional angular velocity vector of the measurement vehicle; The GNSS receiver is used to measure the absolute position coordinates of the survey vehicle; The odometer is used to measure the forward speed of the measuring vehicle; The displacement sensor is used to measure the height of the chassis of the measuring vehicle from the bridge deck; The total station and the prism are used to measure the position coordinates of the measuring vehicle at the starting point and the end point of the target bridge.

[0009] The present invention also provides a Beidou inertial combination rapid measurement method for the linear shape of a large bridge based on the Beidou inertial combination rapid measurement system for the linear shape of a large bridge, comprising: Determining a first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional position information of the measuring vehicle on the measuring route; Determining a second elevation sequence based on the elevation value of the measuring vehicle at the measuring end point and the three-dimensional position information; Determining a target elevation sequence based on the first elevation sequence and the second elevation sequence; Based on the height sequence of the vehicle chassis of the measuring vehicle relative to the bridge deck on the measuring route, the target elevation sequence is corrected to obtain a continuous elevation curve of the target bridge.

[0010] In a possible implementation, the target elevation sequence is corrected based on the height sequence of the chassis of the measuring vehicle relative to the bridge deck on the measuring route to obtain a continuous elevation curve of the target bridge, including: Correcting the height sequence based on the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary to obtain a corrected sequence; The target elevation sequence is corrected based on the correction sequence to obtain a continuous elevation curve of the target bridge.

[0011] In a possible implementation, the step of correcting the height sequence based on the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary to obtain a corrected sequence includes: The correction sequence is obtained by performing a difference operation on the height data of each time stamp in the height sequence and the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary.

[0012] In a possible implementation, the step of correcting the target elevation sequence based on the correction sequence to obtain a continuous elevation curve of the target bridge includes: A difference operation is performed on the height data of the same time stamp in the target elevation sequence and the correction sequence to obtain a continuous elevation curve of the target bridge.

[0013] In a possible implementation, determining the first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional position information of the measuring vehicle on the measuring route includes: The first elevation sequence is determined based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route.

[0014] In a possible implementation, determining the first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route includes: The first high-order sequence is determined based on the following formula:

[0015] in, Indicates that the measuring vehicle is The elevation value at Indicates the elevation value of the measuring vehicle at the measuring starting point, represents the mileage value of the measuring vehicle at the measuring starting point, Indicates that the measuring vehicle is The mileage value at Indicates that the measuring vehicle is The pitch angle at Indicates the mileage increment per unit time.

[0016] In a possible implementation, the three-dimensional position information and the height sequence are time synchronized with reference to the GNSS second pulse.

[0017] The beneficial effects of the present invention are as follows: the Beidou inertial combination rapid measurement system and method for the linear shape of a large bridge provided by the present invention performs linear measurement of the bridge by measuring the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and height of the chassis from the bridge deck of the measuring vehicle. The measurement process is simple, thereby ensuring measurement efficiency. In addition, the vibration displacement caused by the shock absorbing system during the movement of the measuring vehicle is compensated by the height sequence of the vehicle chassis relative to the bridge deck on the measuring route, thereby further improving the accuracy of the target bridge elevation measurement. While realizing the bridge elevation measurement, the present invention ensures both measurement efficiency and measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of an embodiment of a Beidou inertial combination rapid measurement system for the linear shape of a large bridge provided by the present invention; Figure 2 A schematic flow chart of an embodiment of a Beidou inertial combination rapid measurement method for the linear shape of a large bridge provided by the present invention; Figure 3 A schematic structural diagram of another embodiment of a Beidou inertial combination rapid measurement system for the linear shape of a large bridge provided by the present invention; Figure 4 A schematic diagram of an embodiment of data flow in a measurement process provided by the present invention. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0020] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] In the description of the present invention, reference to an "embodiment" means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the described embodiments may be combined with other embodiments.

[0022] Large bridges are important transportation infrastructure and play an important role in economic and social development. During the long-term service of large bridges, their bearing capacity, safety and durability will gradually fail to meet operational requirements, and even disasters and accidents may occur. Therefore, it is very important to carry out structural health monitoring and assessment.

[0023] The bridge alignment can directly invert the internal force changes of its structure under the combined action of various loads, and is an important technical content of bridge structure health monitoring. Due to the large span of large bridges, the main factors affecting their alignment include ambient temperature, load, etc. Therefore, the measurement of their alignment needs to take into account both accuracy and efficiency to ensure that the impact of ambient temperature is minimized.

[0024] Existing bridge alignment measurement methods often fail to strike a balance between accuracy and efficiency, resulting in less than ideal measurement results.

[0025] In order to solve the above problems, the present invention provides a Beidou inertial combination rapid measurement system for the linear shape of a large bridge.

[0026] The specific embodiments are described in detail below: The present invention discloses a Beidou inertial combination rapid measurement system for the linear shape of a large bridge. Figure 1 Come and see, Figure 1 The schematic diagram of the structure of an embodiment of a Beidou inertial combination rapid measurement system for large bridge linear shape provided by the present invention is as follows. The Beidou inertial combination rapid measurement system 100 for large bridge linear shape comprises: The measuring unit 101 is used to measure the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and height of the chassis from the bridge deck of the measuring vehicle; A data acquisition unit 102, used to synchronously record and store the measurement data of the measurement unit in chronological order; The data processing unit 103 is used to perform linear measurement of the bridge based on the measurement data stored in the data acquisition unit.

[0027] During implementation, we can first build a Beidou inertial combination rapid measurement system for the linear shape of a large bridge, which includes a measurement unit, a data acquisition unit and a data processing unit. The measurement unit can measure the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and the height of the chassis from the bridge deck of the measuring vehicle. The height of the measuring vehicle chassis from the bridge deck can be used to compensate for the vibration displacement caused by the shock absorption system during the movement of the measuring vehicle. The data acquisition unit can synchronously record and store the measurement data of the measurement unit in chronological order. The data processing unit can perform linear measurement of the bridge based on the measurement data stored in the data acquisition unit.

[0028] Compared with the prior art, the Beidou inertial combination rapid measurement system for the linear shape of a large bridge provided in this embodiment performs linear measurement of the bridge by measuring the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and the height of the chassis from the bridge deck of the measuring vehicle. The measurement process is simple, thereby ensuring measurement efficiency. In addition, the vibration displacement caused by the shock absorbing system during the movement of the measuring vehicle is compensated by the height sequence of the vehicle chassis relative to the bridge deck on the measuring route, thereby further improving the accuracy of the target bridge elevation measurement. While realizing the bridge elevation measurement, the present invention ensures both measurement efficiency and measurement accuracy.

[0029] Exemplarily, the measuring unit comprises: A survey vehicle, an inertial measurement unit, a GNSS receiver and antenna, a displacement sensor and a prism rigidly fixed on a mounting bracket of the survey vehicle, an odometer rigidly fixed on wheels of the survey vehicle, and a total station set at preset control points at the starting point and the end point of the target bridge.

[0030] Specifically, the measurement unit may include an inertial measurement unit (IMU), a global navigation satellite system (GNSS) receiver and antenna, an odometer, a displacement sensor, a total station, a prism, and a survey vehicle. The inertial measurement unit, the GNSS receiver and antenna, the displacement sensor, and the prism are rigidly fixed on the mounting bracket of the survey vehicle, the odometer is rigidly fixed on the wheels of the survey vehicle, the survey vehicle is the mounting carrier of the above sensors, and the contact surface between the wheels and the bridge deck during the driving process of the survey vehicle is the measured surface of the bridge; the total station is set up on the control point with fixed known position coordinates at the starting and ending points of the bridge.

[0031] Exemplarily, the inertial measurement unit includes a three-axis accelerometer and a three-axis gyroscope, which are used to measure the three-axis acceleration and three-dimensional angular velocity vector of the measurement vehicle; The GNSS receiver is used to measure the absolute position coordinates of the survey vehicle; The odometer is used to measure the forward speed of the measuring vehicle; The displacement sensor is used to measure the height of the chassis of the measuring vehicle from the bridge deck; The total station and the prism are used to measure the position coordinates of the measuring vehicle at the starting point and the end point of the target bridge.

[0032] Specifically, the inertial measurement unit includes a three-axis accelerometer and a three-axis gyroscope, which can be used to measure the three-axis acceleration and three-dimensional angular velocity vector of the measuring vehicle; the GNSS receiver and antenna can be used to measure the absolute position coordinates of the measuring vehicle; the odometer can be used to measure the forward speed of the measuring vehicle; the displacement sensor can be used to measure the height of the measuring vehicle chassis from the bridge deck in real time, thereby compensating for the vibration displacement caused by the shock absorption system during the movement of the measuring vehicle; the total station and prism can be used to measure the position coordinates of the measuring vehicle at the starting and ending points of the bridge.

[0033] The present invention also discloses a Beidou inertial combination rapid measurement method for large bridge linear shape based on the Beidou inertial combination rapid measurement system for large bridge linear shape, combined with Figure 2 Come and see, Figure 2 A schematic flow chart of an embodiment of a Beidou inertial combination rapid measurement method for a large bridge linear shape provided by the present invention includes steps S201 to S204, wherein: In step S201, a first elevation sequence is determined based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture information of the measuring vehicle on the measuring route; In step S202, a second elevation sequence is determined based on the elevation value of the measuring vehicle at the measuring end point and the three-dimensional posture information; In step S203, a target elevation sequence is determined based on the first elevation sequence and the second elevation sequence; In step S204, based on the height sequence of the chassis of the measuring vehicle relative to the bridge deck on the measuring route, the target elevation sequence is corrected to obtain a continuous elevation curve of the target bridge.

[0034] During implementation, the elevation values ​​of the measuring vehicle at the measuring start and end points and the three-dimensional position and posture on the measuring route can be obtained first. The elevation values ​​of the measuring vehicle at the measuring start and end points can be measured by the prism installed on the measuring vehicle and the total station installed at the known coordinate points near the target bridge. The three-dimensional position and posture of the measuring vehicle on the measuring route can be determined by the inertial measurement unit, GNSS receiver and odometer installed on the measuring vehicle.

[0035] Then, the first elevation sequence can be determined by the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional position of the measuring vehicle on the measuring route, and the second elevation sequence can be determined by the elevation value of the measuring vehicle at the measuring end point and the three-dimensional position of the measuring vehicle on the measuring route. Then, the first elevation sequence and the second elevation sequence are combined to determine the target elevation sequence. For example, the elevation data at the same timestamp of the first elevation sequence and the second elevation sequence can be averaged to obtain the target elevation sequence.

[0036] Finally, the target elevation sequence can be corrected according to the height sequence of the chassis of the measuring vehicle relative to the bridge deck on the measuring route to obtain the continuous elevation curve of the target bridge. The height sequence of the chassis of the measuring vehicle relative to the bridge deck on the measuring route can be determined by the displacement sensor installed on the measuring vehicle, which can be used to compensate for the vibration displacement caused by the shock absorption system during the movement of the measuring vehicle, thereby further improving the accuracy of the target bridge elevation measurement. The continuous elevation curve of the target bridge can be used for the bridge line shape evaluation of the target bridge.

[0037] Compared with the prior art, the Beidou inertial combination rapid measurement method for the linear shape of a large bridge provided in this embodiment determines the initial continuous elevation curve of the target bridge by measuring the elevation values ​​of the measuring vehicle at the measuring starting point and the measuring end point, and the three-dimensional posture of the measuring vehicle on the measuring route. The measurement process is simple, thereby ensuring the measurement efficiency. In addition, the vibration displacement caused by the shock absorbing system during the movement of the measuring vehicle is compensated by the height sequence of the vehicle chassis relative to the bridge deck on the measuring route, thereby further improving the accuracy of the target bridge elevation measurement. While realizing the bridge elevation measurement, the present invention ensures both measurement efficiency and measurement accuracy.

[0038] Exemplarily, the target elevation sequence is corrected based on the height sequence of the vehicle chassis of the measuring vehicle relative to the bridge deck on the measuring route to obtain a continuous elevation curve of the target bridge, including: Correcting the height sequence based on the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary to obtain a corrected sequence; The target elevation sequence is corrected based on the correction sequence to obtain a continuous elevation curve of the target bridge.

[0039] Specifically, when the target elevation sequence is corrected according to the height sequence of the vehicle chassis relative to the bridge deck on the measurement route, the height sequence of the vehicle chassis relative to the bridge deck on the measurement route can be corrected according to the height of the vehicle chassis relative to the bridge deck when the measurement vehicle is stationary to obtain a correction sequence. Then, the target elevation sequence is corrected according to the correction sequence, thereby obtaining a continuous elevation curve of the target bridge.

[0040] Exemplarily, the step of correcting the height sequence based on the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary to obtain a corrected sequence includes: The correction sequence is obtained by performing a difference operation on the height data of each time stamp in the height sequence and the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary.

[0041] Specifically, when the height sequence is corrected according to the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary, a difference operation can be performed between the height data of each timestamp in the height sequence and the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary, thereby obtaining a corrected sequence.

[0042] Exemplarily, the step of correcting the target elevation sequence based on the correction sequence to obtain a continuous elevation curve of the target bridge includes: A difference operation is performed on the height data of the same time stamp in the target elevation sequence and the correction sequence to obtain a continuous elevation curve of the target bridge.

[0043] Specifically, when the target elevation sequence is corrected according to the correction sequence, a difference operation may be performed on the height data of the same time stamp in the target elevation sequence and the correction sequence, thereby obtaining a continuous elevation curve of the target bridge.

[0044] Exemplarily, determining the first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional position information of the measuring vehicle on the measuring route includes: The first elevation sequence is determined based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route.

[0045] Specifically, when determining the first elevation sequence according to the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture information of the measuring vehicle on the measuring route, the first elevation sequence can be determined according to the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route. Similarly, the second elevation sequence can also be determined according to the elevation value of the measuring vehicle at the measuring end point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route.

[0046] Exemplarily, determining the first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route includes: The first high-order sequence is determined based on the following formula:

[0047] in, Indicates that the measuring vehicle is The elevation value at Indicates the elevation value of the measuring vehicle at the measuring starting point, represents the mileage value of the measuring vehicle at the measuring starting point, Indicates that the measuring vehicle is The mileage value at Indicates that the measuring vehicle is The pitch angle at Indicates the mileage increment per unit time.

[0048] Specifically, the first elevation sequence can be determined according to the above formula. Similarly, when determining the second elevation sequence, the elevation value of the measuring vehicle at the measuring starting point can be replaced by the elevation value of the measuring vehicle at the measuring end point, and then reverse calculation can be performed.

[0049] For example, the second highest sequence can be determined by the following formula:

[0050] in, Indicates that the measuring vehicle is The elevation value at Indicates the elevation value of the measuring vehicle at the measuring end point, represents the mileage value of the measuring vehicle at the measuring end point, Indicates that the measuring vehicle is The mileage value at Indicates that the measuring vehicle is The pitch angle at Indicates the mileage increment per unit time.

[0051] Exemplarily, the three-dimensional posture information and the height sequence are time synchronized with reference to the GNSS second pulse.

[0052] Specifically, the three-dimensional position information of the measuring vehicle on the measuring route and the height sequence of the vehicle chassis of the measuring vehicle relative to the bridge deck on the measuring route can be time synchronized with the GNSS second pulse as a reference, thereby ensuring the accuracy of data processing.

[0053] The technical solution of the present invention is better described below with reference to a specific embodiment: Combination Figure 3 Come and see, Figure 3 A schematic structural diagram of another embodiment of a Beidou inertial combination rapid measurement system for the linear shape of a large bridge provided by the present invention. The system includes a measurement unit, a data acquisition unit and a data processing unit.

[0054] The measurement unit includes an inertial measurement unit, a GNSS receiver and antenna, an odometer, a displacement sensor, a total station and a prism. The inertial measurement unit, the GNSS receiver and antenna, the displacement sensor and the prism are rigidly fixed on the mounting bracket of the measuring vehicle, the odometer is rigidly fixed on the non-steering wheel hub, and the relative positions between the inertial measurement unit and the GNSS antenna, the displacement sensor, the odometer and the prism are calibrated in advance. The total station is set up at the control point with fixed known position coordinates at the starting and ending points of the bridge.

[0055] The inertial measurement unit includes a three-axis accelerometer and a three-axis gyroscope, which are used to measure the three-axis acceleration and three-dimensional angular velocity vector of the measuring vehicle; the GNSS receiver and antenna are used to measure the absolute position coordinates of the measuring vehicle; the odometer is used to measure the forward speed of the measuring vehicle; the displacement sensor is used to measure the height of the vehicle chassis from the bridge deck in real time, which is used to compensate for the vibration displacement caused by the shock absorption system during the movement of the measuring vehicle; the total station and prism are used to initialize the elevation of the measuring vehicle at the starting and ending points of the bridge.

[0056] The data acquisition unit synchronously records and stores the measurement data of the measurement unit in chronological order. The original measurement values ​​of the inertial measurement unit, GNSS receiver, odometer and displacement sensor are synchronized with the GNSS pulse per second (PPS) as a reference and are stamped with a unified timestamp.

[0057] The data processing unit is used to post-process the original data recorded in the data recording unit.

[0058] Combination Figure 4 Come and see, Figure 4 This is a schematic diagram of an embodiment of the data flow in the measurement process provided by the present invention. The data flow in the measurement process is further explained below through the description of the method steps.

[0059] The inertial measurement method of a continuous bridge elevation curve provided by the present invention comprises the following steps: 1. The measuring vehicle stays still at the starting point of the bridge for a period of time and starts all sensors of the measuring unit. The data acquisition unit synchronously records and stores the measurement data of the measuring unit in chronological order.

[0060] The raw measurements of the inertial measurement unit, GNSS receiver, odometer and displacement sensor are synchronized with the GNSS pulse per second as a reference and are stamped with a unified timestamp.

[0061] 2. While the survey vehicle is stationary, the total station is set up at a known coordinate point near the starting point of the bridge, and the current elevation of the survey vehicle is determined through the prism installed on the survey vehicle.

[0062] The total station is used to measure the elevation at the starting point of the bridge to achieve the elevation transfer from the control point to the vehicle-mounted inertial measurement unit for the elevation initialization of the measuring vehicle, where the precise coordinates of the control point have been measured and obtained in advance.

[0063] 3. After the stationary state is completed, the measuring vehicle drives along the bridge surface to the end of the bridge for measurement, and the data acquisition unit synchronously records and stores the measurement data of the measuring unit in chronological order.

[0064] The survey vehicle should try to maintain a relatively constant speed as it travels along the bridge deck toward the end of the bridge.

[0065] 4. After reaching the end point of the bridge, the survey vehicle remains stationary at the end point for a period of time. While the survey vehicle is stationary, the total station is set up at a known coordinate point near the end point of the bridge. The current elevation of the survey vehicle is determined through the prism installed on the survey vehicle.

[0066] The total station is used to measure the elevation at the end point of the bridge to achieve the elevation transfer from the control point to the vehicle-mounted inertial measurement unit for the elevation initialization of the measuring vehicle, where the precise coordinates of the control point have been measured and obtained in advance.

[0067] 5. Stop data collection after the stationary state is achieved.

[0068] In this example, after step 1 starts data storage, until step 5 is completed, it is ensured that the data storage unit works normally and data storage is not interrupted.

[0069] 6. According to the stationary data at the starting point of the bridge stored in step 1, the initial attitude angle of the inertial navigation measurement unit is calculated.

[0070] When the inertial measurement unit is stationary, the accelerometer's specific force only has gravity input. At this time, the specific force direction is approximately coincident with the opposite direction of the earth's axis of the navigation coordinate system. The origin of the navigation coordinate system is the IMU center, the Z axis is perpendicular to the reference ellipsoid and points vertically downward, the X axis and the Y axis are on the horizontal plane perpendicular to the Z axis, the X axis is parallel to the meridian and points to the North Pole, and the Y axis points to the east. The origin of the sensor coordinate system is the IMU measurement center, and the coordinate axis "XYZ" is defined as the "front-right-down" of the inertial measurement unit. Use the accelerometer in the stationary data of the inertial measurement unit to sense the gravity acceleration and find the horizontal attitude angle:

[0071]

[0072] In the formula, is the initial pitch angle, is the initial roll angle, and are the average outputs of the acceleration of the sensor coordinate system X and sensor coordinate system Y axes during the static period, is the normal acceleration due to gravity.

[0073] The three-axis gyroscope data of the stationary inertial measurement unit is processed to calculate the heading angle of the inertial measurement unit at the initial moment:

[0074] Where A is the initial heading angle, and They are the average outputs of the angular velocity of the sensor coordinate system X and sensor coordinate system Y axes during the static period.

[0075] 7. Perform combined navigation and positioning calculations based on the three-dimensional coordinates calculated by the GNSS receiver, the inertial measurement unit measurements, and the odometer measurements obtained in step 3 to obtain the three-dimensional position and attitude sequence of the measuring vehicle with a GNSS time stamp.

[0076] The combined navigation solution uses mechanical arrangement solution to process the angular velocity and acceleration measurements measured by the inertial measurement unit, and uses the Kalman filter algorithm to fuse the three-dimensional coordinates calculated by GNSS and the speed data measured by the odometer to perform positioning solution.

[0077] 8. Based on the elevation measurement values ​​obtained by the total station, prism, and control points in steps 2 and 4, combined with the position and attitude sequence obtained in step 7, the precise elevation value of any point in the measurement process is obtained through A-INS recursion; INS elevation calculation process:

[0078] In the formula, is the elevation of the measuring vehicle at mileage S, The height of the measuring vehicle at the starting point in step 2. is the mileage value at the starting point, is the mileage value to be calculated, is the pitch angle of the vehicle measured at mileage point S, and ds is the mileage increment per unit time.

[0079] Similarly, use the exact elevation value measured at the end point in step 4 , reverse calculation of accurate high-order sequence.

[0080] 9. Based on the precise elevation values ​​obtained in step 8, close and correct the elevation measurement values ​​in the three-dimensional position sequence in step 7.

[0081] 10. According to the displacement sensor data stored in step 3, the height of the inertial measurement unit from the bridge deck is compensated to obtain a continuous elevation curve of the bridge.

[0082] The present invention uses a total station to measure the elevation at both ends of the bridge, realizes the elevation transfer from the control point to the vehicle-mounted inertial measurement unit, and is used for inertial navigation elevation initialization and elevation closure correction, which can improve the measurement accuracy of the entire system; using an ordinary survey vehicle can effectively improve the measurement efficiency; using a displacement sensor to measure and compensate the height of the survey vehicle from the ground can effectively reduce the vibration error caused by the shock absorption system. The present invention uses an inertial measurement unit, GNSS positioning information, an odometer, a total station to initialize the elevation, and a displacement sensor to compensate for the height above the ground, to estimate and compensate for various errors, and the elevation measurement accuracy of any point on the bridge relative to the control point is better than 1 cm.

[0083] The present invention discloses a Beidou inertial combination rapid measurement system and method for the linear shape of a large bridge. The linear measurement of the bridge is performed by measuring the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and the height of the chassis from the bridge deck of a measuring vehicle. The measurement process is simple, thereby ensuring the measurement efficiency. In addition, the vibration displacement caused by the shock absorbing system during the movement of the measuring vehicle is compensated by the height sequence of the vehicle chassis relative to the bridge deck on the measuring route, thereby further improving the accuracy of the target bridge elevation measurement. The present invention ensures both the measurement efficiency and the measurement accuracy while realizing the bridge elevation measurement.

[0084] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A Beidou inertial combination rapid measurement system for the linear shape of a large bridge, characterized in that: include: The measuring unit is used to measure the three-axis acceleration, three-dimensional angular velocity vector, absolute position coordinates, forward speed and height of the chassis from the bridge deck of the measuring vehicle; A data acquisition unit, used to synchronously record and store the measurement data of the measurement unit in chronological order; The data processing unit is used to perform linear measurement of the bridge based on the measurement data stored in the data acquisition unit.

2. The Beidou Inertial Combined Rapid Measurement System for the Linear Shape of a Large Bridge according to claim 1 is characterized in that: The measuring unit comprises: A survey vehicle, an inertial measurement unit, a GNSS receiver and antenna, a displacement sensor and a prism rigidly fixed on a mounting bracket of the survey vehicle, an odometer rigidly fixed on wheels of the survey vehicle, and a total station set at preset control points at the starting point and the end point of the target bridge.

3. The Beidou Inertial Combined Rapid Measurement System for the Linear Shape of a Large Bridge according to claim 2, characterized in that: The inertial measurement unit includes a three-axis accelerometer and a three-axis gyroscope, which are used to measure the three-axis acceleration and three-dimensional angular velocity vector of the measurement vehicle; The GNSS receiver is used to measure the absolute position coordinates of the survey vehicle; The odometer is used to measure the forward speed of the measuring vehicle; The displacement sensor is used to measure the height of the chassis of the measuring vehicle from the bridge deck; The total station and the prism are used to measure the position coordinates of the measuring vehicle at the starting point and the end point of the target bridge.

4. A Beidou Inertial Combined Rapid Measurement Method for Large Bridge Alignment Based on the Beidou Inertial Combined Rapid Measurement System for Large Bridge Alignment According to any One of Claims 1 to 3, characterized in that: include: Determining a first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional position information of the measuring vehicle on the measuring route; Determining a second elevation sequence based on the elevation value of the measuring vehicle at the measuring end point and the three-dimensional position information; Determining a target elevation sequence based on the first elevation sequence and the second elevation sequence; Based on the height sequence of the vehicle chassis of the measuring vehicle relative to the bridge deck on the measuring route, the target elevation sequence is corrected to obtain a continuous elevation curve of the target bridge.

5. The Beidou Inertial Combination Rapid Measurement Method for the Linear Shape of a Large Bridge according to claim 4 is characterized in that: The method of correcting the target elevation sequence based on the height sequence of the vehicle chassis relative to the bridge deck on the measurement route to obtain a continuous elevation curve of the target bridge includes: Correcting the height sequence based on the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary to obtain a corrected sequence; The target elevation sequence is corrected based on the correction sequence to obtain a continuous elevation curve of the target bridge.

6. The Beidou Inertial Combination Rapid Measurement Method for the Linear Shape of a Large Bridge according to claim 5 is characterized in that: The step of correcting the height sequence based on the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary to obtain a corrected sequence comprises: The correction sequence is obtained by performing a difference operation on the height data of each time stamp in the height sequence and the height of the vehicle chassis relative to the bridge deck when the measuring vehicle is stationary.

7. The Beidou Inertial Combination Rapid Measurement Method for the Linear Shape of a Large Bridge according to claim 5 is characterized in that: The step of correcting the target elevation sequence based on the correction sequence to obtain a continuous elevation curve of the target bridge includes: The height data of the same time stamp in the target elevation sequence and the correction sequence are subjected to difference calculation to obtain a continuous elevation curve of the target bridge.

8. The Beidou Inertial Combination Rapid Measurement Method for the Linear Shape of a Large Bridge according to claim 4 is characterized in that: The step of determining a first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional position information of the measuring vehicle on the measuring route comprises: The first elevation sequence is determined based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route.

9. The Beidou Inertial Combination Rapid Measurement Method for the Linear Shape of a Large Bridge according to claim 8 is characterized in that: The determining of the first elevation sequence based on the elevation value of the measuring vehicle at the measuring starting point and the three-dimensional posture and mileage value of the measuring vehicle on the measuring route comprises: The first high-order sequence is determined based on the following formula: in, Indicates that the measuring vehicle is The elevation value at Indicates the elevation value of the measuring vehicle at the measuring starting point, represents the mileage value of the measuring vehicle at the measuring starting point, Indicates that the measuring vehicle is The mileage value at Indicates that the measuring vehicle is The pitch angle at Indicates the mileage increment per unit time.

10. The Beidou Inertial Combination Rapid Measurement Method for the Linear Shape of a Large Bridge according to any one of claims 4 to 9, characterized in that: The three-dimensional position information and the height sequence are time synchronized with reference to the GNSS second pulse.

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