CN113503896B - Mileage calibration method of railway measurement trolley based on positioning system - Google Patents

Abstract

The invention provides a mileage calibration method of a railway engineering measurement trolley based on a positioning system, which divides the environment of a railway construction site, comprises multiple combination conditions of tunnel, track and signal, adopts different positioning measurement modes or different positioning measurement mode combinations according to different conditions, and combines the advantages of various positioning measurement modes to mutually compensate the defects, wherein the positioning measurement modes comprise modeling positioning realized by a three-dimensional laser scanner, odometer positioning and real-time dynamic carrier phase difference technology.

Description

A mileage calibration method for railway measuring trolley based on positioning system

Technical Field

The invention relates to the field of engineering surveying, and in particular to a mileage calibration method for a railway engineering surveying trolley based on a positioning system.

Background Art

In recent years, railway construction has been a key project of the country. With the implementation of regional railway projects, it has greatly promoted the economic development of the region, eliminated regional restrictions, and accelerated the promotion and exchange of regional culture. In the process of railway construction, mileage measurement is an extremely important part. Through mileage measurement, accurate layout of trackside equipment can be achieved. In the traditional scheme, the mileage measurement of the line is completed by artificial detection with the help of some detection tools, and the mileage data is recorded by artificial marking. However, with the spread of railway lines, the environment of railway construction sites has become more complex, including tunnels, wastelands, water flows and other construction environments; these harsh natural environments have caused great obstacles to the traditional method of artificial mileage measurement. On the other hand, data errors are prone to occur through artificial measurement, which increases the workload of inspection personnel and increases the cost of mileage detection. Therefore, it is of great significance to improve the intelligence of the railway mileage measurement process and effectively reduce the error of mileage measurement for railway construction.

Summary of the invention

The purpose of the present invention is to solve the deficiencies of the prior art and to provide a mileage calibration method for a railway engineering surveying trolley based on a positioning system.

In order to solve the above technical problems, the present invention adopts the following solutions:

A method for calibrating the mileage of a railway engineering measurement vehicle based on a positioning system comprises the following steps:

Step 1: The car determines whether it is currently inside or outside the tunnel based on the light sensitivity value of the photosensor installed on its body; if the car is inside the tunnel, go to step 2; if the car is outside the tunnel, go to step 5;

Step 2: If the car is in the tunnel, the pressure values sensed by the pressure sensors respectively arranged on the inner and outer wheels of the car are further used to determine whether the car is currently on the track or in the trackless area; if the car is in the trackless area, the process proceeds to step 3; if the car is on the track, the process proceeds to step 4;

Step 3: If the car is in the tunnel and not on the track, a three-dimensional laser scanner is set on the car to achieve modeling positioning, obtain scanning modeling coordinate data, and use it as the real-time coordinates of the car, and return to step 1;

Step 4: When the car is in the tunnel and on the track, the odometer set on the wheels of the car is used to count and obtain the travel distance; the mileage coordinate data is obtained by the travel distance and used as the real-time coordinates of the car, and then return to step 1;

Step 5: If the car is outside the tunnel, the signal value of the signal receiving device set on the car body is further used to determine whether the car's received signal can reach the set strength; if the car's received signal reaches the set signal strength, proceed to step 6; otherwise, proceed to step 7;

Step 6: When the received signal reaches the set signal strength, the car's coordinate data is measured through real-time dynamic carrier phase differential technology to obtain the car's differential positioning coordinates, which are used as the car's real-time coordinates, and then return to step 1;

Step 7: If the signal received by the car does not reach the set signal strength, it is further determined whether the car is currently on the track or in the trackless area according to the pressure values sensed by the pressure sensors respectively arranged on the inner and outer wheels of the car; if the car is in the trackless area, it proceeds to step 8; if the car is on the track, it proceeds to step 9;

Step 8: If the car is not on the track, the real-time dynamic carrier phase difference technology is combined with the odometer set on the car wheel and the three-dimensional laser scanner set on the car to comprehensively determine the real-time position of the car, and return to step 1;

Step 9: If the car is on the track, the real-time dynamic carrier phase difference technology is combined with the odometer set on the car's wheels to comprehensively determine the real-time position of the car, and return to step 1.

Furthermore, in step 1, the sensitivity change rate of the photosensor is used to determine whether the car is inside or outside the tunnel, the sensitivity parameter is set to λ, and the sensitivity change rate Δλ at the set time interval is taken; the absolute value of the sensitivity change rate Δλ is compared with the set sensitivity change threshold Δλ ₀ , as shown below:

For the case of |Δλ|≤Δλ ₀ , if the state of the car in the previous time interval is inside the tunnel, then the state of the car is kept inside the tunnel; conversely, if the state of the car in the previous time interval is outside the tunnel, then the state of the car is kept outside the tunnel.

Furthermore, the inner and outer wheels in step 2 include an inner track wheel and an outer rubber wheel, wherein the inner track wheel is used for traveling on the track, and the outer rubber wheel is used for traveling on the ground; pressure sensors are provided on both the inner track wheel and the outer rubber wheel, wherein if the pressure sensed by the pressure sensor on the outer rubber wheel is greater than a set pressure value, it is considered that the trolley is traveling in a trackless area; if the pressure sensed by the pressure sensor on the inner track wheel is greater than a set pressure value, it is considered that the trolley is traveling on the track.

Furthermore, in step 3, the vehicle performs non-contact scanning and measurement of the space in which it is located by a three-dimensional laser scanner arranged on the vehicle body; wherein a mark is arranged at the calibration point, and the mark is a black and white reflective cross target or a marker ball; and the process of the three-dimensional laser scanner acquiring coordinate information includes the following steps:

Step 31: The vehicle obtains and stores the position information of the calibration point by scanning with a three-dimensional laser scanner; wherein the position information of the calibration point includes the spatial coordinates of the calibration point in the same spatial coordinate system or reference system and the point cloud data of the surface spectral characteristics of the calibration point;

Step 32: The car obtains the spatial coordinates of other entities in the space and a point cloud data set of their surface spectral characteristics through a 3D laser scanner;

Step 33: Obtain a three-dimensional solid model of the space through point cloud stitching and filtering analysis;

Step 34: Obtain scanning modeling coordinate data (x3, y3, z3) of the target point through the calibration points in the three-dimensional solid model;

In step 34, the scanning modeling coordinates are obtained relative to the calibration point, and the geographical location of the calibration point is set in advance; the geographical location of the target point is obtained based on the geographical location of the calibration point and the scanning modeling coordinate data of the target point relative to the calibration point.

Furthermore, in step 4, the trolley obtains the travel distance △l and the travel speed v through the odometer set on the wheel, and obtains the travel distance of the trolley in each direction in combination with the level meter set on the trolley, and obtains the mileage coordinate data (x2, y2, z2) based on the accumulated travel distance.

Furthermore, the calculation of the travel distance of the vehicle in each direction is shown in the following formula:

Wherein, _Δy2 represents the distance traveled by the car in the Y direction; _Δx2 represents the distance traveled by the car in the X direction; _Δz2 represents the distance traveled by the car in the Z direction; _t1 represents the time taken for the pressure sensors on the inner and outer wheels to change from the flat ground pressure value on the flat ground to the non-flat ground pressure value and then back to the flat ground pressure value, or the time taken for the inclination angle of the level to change from zero to a non-zero value and then back to zero, where the flat ground pressure value is the pressure sensing value of the pressure sensor when the level is 0; _vt represents the speed of the car obtained by the odometer at time t; _θt represents the inclination angle sensed by the level at time t; _θ2t is the complementary angle of _θt .

Furthermore, in the calculation process of the mileage coordinate data and the travel distance, a bump error elimination method is used to eliminate or reduce the travel distance measurement error caused by the bump of the car; the bump error elimination method includes the following steps:

Step S1: The built-in level of the car obtains the inclination angle of the car; if the inclination angle exceeds the set range, it is considered that the car is passing through a slope or a depression. At this time, the initial velocity of the car corresponding to the inclination angle is obtained through the odometer, and the process goes to step S2; if the inclination angle does not exceed the set range, it is considered that the car is traveling on flat ground, and the process goes to step S5;

Step S2: judging whether the trolley is in the air according to the pressure sensors arranged on the inner and outer wheels; if the trolley is in the air, proceeding to step S3; otherwise, proceeding to step S4;

Step S3: When the car flies over a slope or depression, the flying angle and initial flying speed of the car are obtained by combining a level meter with pressure sensors on the inner and outer wheels. The flying trajectory and landing coordinates of the car are obtained by simulation calculation. The travel distance of the car is obtained according to the landing coordinates, and the step ends.

Step S4: The trolley passes through a slope or a depression without being airborne. According to the inclination angle of the trolley obtained by the level meter, it is determined whether the trolley passes through a slope or a depression. If the inclination angle is greater than the maximum value of the set range, it is considered that the trolley passes through the slope; if the inclination angle is less than the minimum value of the set range, it is considered that the trolley passes through the depression; then proceed to step S5;

Step S5: Obtain the travel distance of the car in each direction by combining the level meter with the odometer, and end the step.

Furthermore, in step S1, the tilt angle represents the tilt angle with respect to the horizontal plane;

In step S2, if the pressure sensing value of the pressure sensor provided on the inner and outer wheels of the trolley suddenly changes to 0, it is considered that the trolley is in the air, and the moment when the pressure sensing value of the pressure sensor suddenly changes to 0 is regarded as the moment when the trolley is in the air;

In the simulation calculation of the flying trajectory and landing coordinates of the car in step S3, firstly, the traveling direction θ ₁ of the car is obtained through the level meter, and the flying angle θ ₀ formed by the car and the horizontal plane at the moment when the pressure sensor of the car suddenly changes to 0 is obtained; the flying initial velocity v ₀ of the car at the moment of flying is obtained through the odometer set on the car; according to the parabola theorem, the following formula is obtained:

ΔZ′ ₂ = 0

Among them, Δs′ represents the calculated displacement distance of the vehicle in the plane; Δt ₂ ′ represents the calculated displacement distance of the vehicle in the plane in the Y direction of the spatial position coordinate; Δx ₂ ′ represents the calculated displacement distance of the vehicle in the plane in the X direction of the spatial position coordinate; t′ represents the calculated time of the vehicle falling back to the plane at the moment of taking off after taking off; g represents the acceleration of gravity; the calculated displacement distance in the plane represents the calculated displacement distance of the vehicle falling back to the horizontal plane at the moment of taking off after taking off;

In order to ensure that there is no drop before and after the car leaves the ground and lands, the calculated time t′ in the plane is compared with the actual time t ₀ , where the actual time t ₀ represents the length of time that the pressure sensor is continuously at 0. If |tt ₀ | is less than the set threshold, no correction is required, and Δy ₂ ′, Δx ₂ ′ and ΔZ′ ₂ are directly substituted into the accumulated distance of the car in each direction. If |tt ₀ | is greater than the set threshold, correction is performed according to the following formula:

Among them, Δy ₂ ^* represents the calculated distance of the vehicle's corrected displacement in the Y direction; Δx ₂ ^* represents the calculated distance of the vehicle's corrected displacement in the X direction; Δz ₂ ^* represents the calculated distance of the vehicle's corrected displacement in the Z direction; the corrected Δx ₂ ^* , Δy ₂ ^* and Δz ₂ ^* are substituted into the accumulated travel distance of the vehicle in each direction;

In step S5, the travel distance of the trolley in each direction is obtained by the aforementioned formula for calculating the travel distance of the trolley based on the Pythagorean theorem; wherein the travel distance of the trolley in each direction is shown in the following formula:

Wherein, _Δy2 represents the distance traveled by the car in the Y direction; _Δx2 represents the distance traveled by the car in the X direction; _Δz2 represents the distance traveled by the car in the Z direction; _t1 represents the time taken for the pressure sensors on the inner and outer wheels to change from the flat ground pressure value on the flat ground to the non-flat ground pressure value and then back to the flat ground pressure value, or the time taken for the inclination angle of the level to change from zero to a non-zero value and then back to zero, where the flat ground pressure value is the pressure sensing value of the pressure sensor when the level is 0; _vt represents the speed of the car obtained by the odometer at time t; _θt represents the inclination angle sensed by the level at time t; _θ2t is the complementary angle of _θt .

Furthermore, the positioning of the real-time dynamic carrier phase difference technology in step 6 includes the following steps:

Step 61: The base station transmits the observation value and the station coordinate information to the mobile station via the data link;

Step 62: The mobile station receives the observation value and the station coordinate information, and collects satellite observation data through the satellite;

Step 63: The mobile station composes the received and collected data into differential observation values to obtain the differential positioning coordinates of the mobile station;

The mobile station in step 61 is a small vehicle.

Furthermore, in step 8, the real-time dynamic carrier phase difference technology is combined with the odometer set on the wheels of the car and the three-dimensional laser scanner set on the car to comprehensively determine the real-time position of the car, including the following steps:

Step 81: determine the time node t' when the signal received by the car reaches the set signal strength closest to the current time, and use the real-time dynamic carrier phase difference technology corresponding to the time node to obtain the differential positioning coordinates (x'1, y'1, z'1) of the car;

Step 82: Obtain the travel distance △l collected by the odometer from the time node t' to the current time;

Step 83: Draw a circle with the differential positioning coordinates (x'1, y'1, z'1) as the center and the travel distance △l as the radius; the range of the circular area represents the current position range of the car;

Step 84: Determine the relationship between the distance between the differential positioning coordinates (x1, y1, z1) of the car obtained by real-time dynamic carrier phase difference technology at the current time and the differential positioning coordinates (x'1, y'1, z'1) at the time node t' and the travel distance △l; if The differential positioning coordinates (x1, y1, z1) at the current time are used as the real-time coordinates of the car; if The scanning modeling coordinate data (x3, y3, z3) obtained by the 3D laser scanner is used as the real-time coordinates of the car; end the step;

In step 9, the real-time dynamic carrier phase difference technology is combined with the odometer set on the wheels of the car to comprehensively determine the real-time position of the car, including the following steps:

Step 91: determine the time node t' when the signal received by the car reaches the set signal strength closest to the current time, and use the real-time dynamic carrier phase difference technology corresponding to the time node to obtain the differential positioning coordinates (x'1, y'1, z'1) of the car;

Step 92: Obtain the travel distance △l collected by the odometer from the time node t' to the current time;

Step 93: Draw a circle with the differential positioning coordinates (x'1, y'1, z'1) as the center and the travel distance △l as the radius; the range of the circular area represents the current position range of the car;

Step 94: Determine the relationship between the distance between the differential positioning coordinates (x1, y1, z1) of the car obtained by real-time dynamic carrier phase difference technology at the current time and the differential positioning coordinates (x'1, y'1, z'1) at the time node t' and the travel distance △l; if The differential positioning coordinates (x1, y1, z1) at the current time are used as the real-time coordinates of the car; if Then use the car's odometer to obtain the mileage coordinate data (x2, y2, z2) as the car's real-time coordinates; end the step.

The beneficial effects of the present invention are:

By dividing the environment of the railway construction site into multiple combinations, including whether there are tunnels, tracks, and signals, different positioning measurement methods or combinations of positioning measurement methods are used for different situations, and the advantages of various positioning measurement methods are combined to make up for each other's shortcomings. The positioning measurement methods include three-dimensional laser scanners to achieve modeling positioning, odometer positioning, and real-time dynamic carrier phase difference technology;

By combining the odometer with the level, the travel distance of the car in the three directions of X, Y, and Y is obtained, and the mileage coordinate data of the car is accurately calculated to reduce errors;

By setting mileage reference points, the accumulated error of the vehicle mileage measurement is distributed within the interval of each reference point to avoid continuous accumulation of errors, which will affect the entire route.

The bump error elimination method is used to eliminate the flying error of the car during the odometer positioning process or the statistical process of the travel distance △l. The pressure sensor, odometer and level are combined to achieve accurate measurement of the car's mileage coordinate data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a general flow chart of Embodiment 1 of the present invention;

FIG2 is a flowchart of determining the light sensitivity value of a vehicle in accordance with the first embodiment of the present invention;

FIG3 is a schematic diagram of modeling of a three-dimensional laser scanner according to Embodiment 1 of the present invention;

FIG4 is a schematic diagram of positioning using a real-time dynamic carrier phase difference technology according to Embodiment 1 of the present invention;

FIG5 is a schematic diagram of the position range of the trolley in step 8 and step 9 in embodiment 1 of the present invention;

FIG6 is a schematic diagram of the moment when the trolley of the second embodiment of the present invention is lifted off;

FIG7 is a schematic diagram of a parabola of a trolley according to a second embodiment of the present invention;

FIG8 is a schematic diagram of a vehicle passing through a slope and a depression in Embodiment 2 of the present invention.

DETAILED DESCRIPTION

The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

Embodiment 1:

As shown in FIG1 , a method for calibrating the mileage of a railway engineering measurement vehicle based on a positioning system includes the following steps:

Step 1: The car determines whether it is currently inside or outside the tunnel based on the change in the light sensitivity value of the photosensitive sensor installed on its body; if the car is inside the tunnel, proceed to step 2; if the car is outside the tunnel, proceed to step 5;

Step 2: If the car is in the tunnel, the pressure values sensed by the pressure sensors respectively arranged on the inner and outer wheels of the car are further used to determine whether the car is currently on the track or in the trackless area; if the car is in the trackless area, the process proceeds to step 3; if the car is on the track, the process proceeds to step 4;

Step 3: If the car is in the tunnel and not on the track, a three-dimensional laser scanner is set on the car to achieve modeling positioning, obtain scanning modeling coordinate data, and use it as the real-time coordinates of the car, and return to step 1;

Step 4: When the car is in the tunnel and on the track, the odometer set on the wheels of the car is used to count and obtain the travel distance; the mileage coordinate data is obtained by the travel distance and used as the real-time coordinates of the car, and then return to step 1;

Step 5: When the car is outside the tunnel, it is further determined whether the signal received by the car can reach the set strength according to the signal value of the signal receiving device set on the car body; if the signal received by the car reaches the set signal strength, it proceeds to step 6; otherwise, it proceeds to step 7; wherein reaching the set signal strength means that the signal received by the car is greater than or equal to the set signal strength; in some other implementations, whether the received signal is greater than the set signal strength can also be used as a basis for judgment;

Step 6: When the received signal reaches the set signal strength, the car's coordinate data is measured through the real-time kinematic (RTK) carrier phase differential technology to obtain the car's differential positioning coordinates, which are used as the car's real-time coordinates, and then return to step 1;

Step 7: If the signal received by the car does not reach the set signal strength, it is further determined whether the car is currently on the track or in the trackless area according to the pressure values sensed by the pressure sensors respectively arranged on the inner and outer wheels of the car; if the car is in the trackless area, it proceeds to step 8; if the car is on the track, it proceeds to step 9;

Step 8: If the car is not on the track, the real-time dynamic carrier phase difference technology is combined with the odometer set on the car wheel and the three-dimensional laser scanner set on the car to comprehensively determine the real-time position of the car, and return to step 1;

Step 9: If the car is on the track, the real-time dynamic carrier phase difference technology is combined with the odometer set on the car's wheels to comprehensively determine the real-time position of the car, and return to step 1.

As shown in FIG2 , the judgment in step 1 as to whether the car is inside or outside the tunnel is mainly made by the sensitivity change rate of the photosensor. In this example, the sensitivity parameter is set to λ, and the sensitivity change rate Δλ at a set time interval is taken. The set time interval can be 1 minute or 30 seconds. The absolute value of the sensitivity change rate Δλ is compared with the set sensitivity change threshold Δλ ₀ , as shown below:

For the case of |Δλ|≤Δλ ₀ , if the state of the car in the previous time interval is inside the tunnel, then the state of the car is kept inside the tunnel; conversely, if the state of the car in the previous time interval is outside the tunnel, then the state of the car is kept outside the tunnel.

If the car is in a tunnel, it is considered that the car has no signal. Therefore, when the car is in a tunnel, it is not necessary to read the signal value of the signal receiving device.

The inner and outer wheels in step 2 include an inner track wheel and an outer rubber wheel, wherein the inner track wheel is used for traveling on the track, and the outer rubber wheel is used for traveling on the ground. In this example, pressure sensors are provided on both the inner track wheel and the outer rubber wheel, wherein if the pressure sensed by the pressure sensor on the outer rubber wheel is greater than the set pressure value, it is considered that the trolley is traveling in a trackless area; similarly, if the pressure sensed by the pressure sensor on the inner track wheel is greater than the set pressure value, it is considered that the trolley is traveling on the track. The set pressure value is set to avoid misjudgment caused by the outer rubber wheel touching the ground when the trolley is traveling on the track, or by the inner track wheel touching the ground when the trolley is traveling on the ground.

As shown in FIG3 , in step 3, the vehicle uses a three-dimensional laser scanner installed on the vehicle body to perform non-contact scanning and measurement of the space in which it is located. A mark is set at the calibration point, and the mark can be a black and white reflective cross target or a marker ball. The process of obtaining coordinate information by the three-dimensional laser scanner includes the following steps:

Step 31: The vehicle obtains and stores the position information of the calibration point by scanning with a three-dimensional laser scanner; wherein the position information of the calibration point includes the spatial coordinates of the calibration point in the same spatial coordinate system or reference system and the point cloud data of the surface spectral characteristics of the calibration point; in this example, the same spatial coordinate system or reference system is the space obtained by scanning with the scanner;

Step 32: The vehicle obtains the spatial coordinates of other entities in the space and a point cloud data set of their surface spectral characteristics through a 3D laser scanner;

Step 33: Obtain a three-dimensional solid model of the space through point cloud stitching and filtering analysis;

Step 34: Obtain the scanning modeling coordinate data (x3, y3, z3) of the target point through the calibration points in the three-dimensional solid model.

In step 34, the scanning modeling coordinates are obtained relative to the calibration point. In the actual operation process, the geographical location of the calibration point will be set. According to the geographical location of the calibration point, the target point's geographical location is obtained in combination with the scanning modeling coordinate data of the target point relative to the calibration point. In the three-dimensional solid model, any two points in the three-dimensional solid model can be specified, and the position, distance and relative displacement of the two points in space can be calculated. In addition, in other steps, the scanning modeling coordinate data can also be obtained through the process of steps 31 to 34.

It should be noted that the data obtained by the 3D laser scanner is huge, the amount of calculation is also large, the modeling time is long, the computer configuration requirements are high, and the power consumption is also large. Therefore, it is not convenient to use it on the whole line. In this case, the 3D laser scanner will only be enabled when the car is not on the track and the signal value received by the car does not reach the set signal strength. Because when the signal value received by the car does not reach the set signal strength, it is difficult to determine the coordinate position of the car in real time through the real-time dynamic carrier phase difference technology. On the other hand, the car is in a trackless area. The environment in the trackless area is complex and the car may be bumpy. At this time, it is difficult to accurately obtain the mileage of the car through the odometer set on the wheel. Therefore, the 3D laser scanner is enabled for positioning or auxiliary positioning.

In step 4, the odometer is a device for measuring the distance and speed of the vehicle. The mileage is calculated by measuring the rotation angle of the axle. The odometer is a Hall encoder, a rotary rheostat, or a photoelectric rotary encoder. In this example, a photoelectric rotary encoder is used as the odometer. The trolley obtains the travel distance △l and the travel speed v of the wheel through the odometer set on the wheel, and combines the level set on the trolley to obtain the travel distance of the trolley in each direction, and obtains the mileage coordinate data (x2, y2, z2) according to the accumulation of the travel distance.

Among them, the travel distance of the car in each direction is obtained by the Pythagorean theorem, as shown in the following formula:

Among them, Δy ₂ represents the distance traveled by the car in the Y direction; Δx ₂ represents the distance traveled by the car in the X direction; Δz ₂ represents the distance traveled by the car in the Z direction; t ₁ represents the time taken for the pressure sensor on the inner and outer wheels to change from the flat ground pressure value on the flat ground to the non-flat ground pressure value and then back to the flat ground pressure value, or the time taken for the inclination angle of the level to change from zero to a non-zero value and then back to zero, where the flat ground pressure value is the pressure sensing value of the pressure sensor when the level is 0; v _t represents the speed of the car obtained by the odometer at time t; θ _t represents the inclination angle sensed by the level at time t; θ _2t is the complementary angle of θ _t . It should be noted that in this example, when the car is traveling without a track, the wheel odometer only records the travel distance △l of the wheel, and does not accumulate the travel distance △l to obtain the mileage coordinate data.

It should be noted that in some other implementations, the mileage coordinate data of the vehicle can also be obtained directly through the travel distance and direction of the vehicle. At this time, the height coordinate z2 in the mileage coordinate data of the vehicle is replaced by the height coordinate in the scanning modeling coordinate data or the height coordinate obtained by real-time dynamic carrier phase difference technology.

As shown in Figure 4, the real-time dynamic carrier phase differential technology in step 6 is mainly implemented with the help of satellite positioning. Traditional high-precision satellite positioning must use carrier phase observations, while RTK positioning technology is a real-time dynamic positioning technology based on carrier phase observations, which can provide real-time spatial positioning results of the measuring station in a specified coordinate system with extremely high accuracy; the number of satellites is required to be maintained at more than four. The positioning of real-time dynamic carrier phase differential technology includes the following steps:

Step 61: The base station transmits the observation value and the station coordinate information to the mobile station via the data link;

Step 62: The mobile station receives the observation value and the station coordinate information, and collects satellite observation data through the satellite;

Step 63: The mobile station composes the received and collected data into differential observation values to obtain the differential positioning coordinates of the mobile station.

The mobile station in step 61 is a small vehicle in this example. In other steps, the differential positioning coordinates of the mobile station, that is, the small vehicle, can also be obtained through steps 61 to 63.

As shown in FIG5 , in step 8, the real-time dynamic carrier phase difference technology is combined with the odometer set on the wheels of the car and the three-dimensional laser scanner set on the car to comprehensively determine the real-time position of the car, including the following steps:

Step 81: determine the time node t' when the signal received by the car reaches the set signal strength closest to the current time, and use the real-time dynamic carrier phase difference technology corresponding to the time node to obtain the differential positioning coordinates (x'1, y'1, z'1) of the car;

Step 82: Obtain the travel distance △l collected by the odometer from the time node t' to the current time;

Step 83: Draw a circle with the differential positioning coordinates (x'1, y'1, z'1) as the center and the travel distance △l as the radius; the range of the circular area represents the current position range of the car;

Step 84: Determine the relationship between the distance between the differential positioning coordinates (x1, y1, z1) of the car obtained by real-time dynamic carrier phase difference technology at the current time and the differential positioning coordinates (x'1, y'1, z'1) at the time node t' and the travel distance △l; if The differential positioning coordinates (x1, y1, z1) at the current time are used as the real-time coordinates of the car; if The scanning modeling coordinate data (x3, y3, z3) obtained by the 3D laser scanner is used as the real-time coordinates of the car; end the step.

In step 9, because the trolley is on the track, the odometer can more accurately record the travel distance △l of the trolley, and then obtain accurate mileage coordinate data (x2, y2, z2). Therefore, when the trolley is on the track outside the tunnel, the real-time position of the trolley can be determined only by the real-time dynamic carrier phase difference technology combined with the odometer set on the wheels of the trolley. The real-time position of the trolley is comprehensively determined by the real-time dynamic carrier phase difference technology combined with the odometer set on the wheels of the trolley, including the following steps:

Step 91: determine the time node t' when the signal received by the car reaches the set signal strength closest to the current time, and use the real-time dynamic carrier phase difference technology corresponding to the time node to obtain the differential positioning coordinates (x'1, y'1, z'1) of the car;

Step 92: Obtain the travel distance △l collected by the odometer from the time node t' to the current time;

Step 93: Draw a circle with the differential positioning coordinates (x'1, y'1, z'1) as the center and the travel distance △l as the radius; the range of the circular area represents the current position range of the car;

Step 94: Determine the relationship between the distance between the differential positioning coordinates (x1, y1, z1) of the car obtained by real-time dynamic carrier phase difference technology at the current time and the differential positioning coordinates (x'1, y'1, z'1) at the time node t' and the travel distance △l; if The differential positioning coordinates (x1, y1, z1) at the current time are used as the real-time coordinates of the car; if Then use the car's odometer to obtain the mileage coordinate data (x2, y2, z2) as the car's real-time coordinates; end the step.

It should be noted that due to wheel slippage and other phenomena, the mileage count of the car will produce errors. In order to avoid the accumulation of errors, mileage reference points are set on the travel path of the car. During the travel of the car, if it passes through a mileage reference point, the mileage coordinate data is calibrated by manually setting the coordinate position data of the mileage reference point. The purpose is to distribute the error of the mileage count within the interval of each mileage reference point to avoid the accumulation of errors. In this example, the mileage reference point uses the CPⅢ point. In addition, the mileage reference point can also be used as the calibration point in step 34.

During the implementation process, the environment of the railway construction site is divided into multiple combinations, including whether there are tunnels, tracks, and signals. Different positioning and measurement methods or different combinations of positioning and measurement methods are used for different situations. The advantages of various positioning and measurement methods are combined to make up for each other's shortcomings. The positioning and measurement methods include three-dimensional laser scanners to achieve modeling positioning, odometer positioning, and real-time dynamic carrier phase difference technology. The odometer is combined with a level to obtain the travel distance of the car in the X, Y, and Y directions, and the mileage coordinate data of the car is accurately calculated to reduce errors. By setting mileage reference points, the cumulative error of the car mileage measurement is distributed in the interval of each reference point to avoid continuous accumulation of errors and thus affect the entire line.

Embodiment 2:

This embodiment is obtained by improving the first embodiment. In the process of calculating the mileage coordinate data or the travel distance, the vehicle will be bumpy, especially in the complex environment of the trackless area, resulting in measurement errors. Therefore, in the process of calculating the mileage coordinate data and the travel distance, a bump error elimination method is used to eliminate or reduce the travel distance measurement error caused by the bump of the vehicle. The bump error elimination method includes the following steps:

Step S1: The built-in level of the car obtains the inclination angle of the car; if the inclination angle exceeds the set range, it is considered that the car is passing through a slope or a depression. At this time, the initial velocity of the car corresponding to the inclination angle is obtained through the odometer, and the process goes to step S2; if the inclination angle does not exceed the set range, it is considered that the car is traveling on flat ground, and the process goes to step S5;

Step S2: judging whether the trolley is in the air according to the pressure sensors arranged on the inner and outer wheels; if the trolley is in the air, proceeding to step S3; otherwise, proceeding to step S4;

Step S3: When the car flies over a slope or depression, the flying angle and initial flying speed of the car are obtained by combining a level meter with pressure sensors on the inner and outer wheels. The flying trajectory and landing coordinates of the car are obtained by simulation calculation. The travel distance of the car is obtained according to the landing coordinates, and the step ends.

Step S4: The trolley passes through a slope or a depression without being airborne. According to the inclination angle of the trolley obtained by the level meter, it is determined whether the trolley passes through a slope or a depression. If the inclination angle is greater than the maximum value of the set range, it is considered that the trolley passes through the slope; if the inclination angle is less than the minimum value of the set range, it is considered that the trolley passes through the depression; then proceed to step S5; in this example, the set range is 0;

Step S5: Obtain the travel distance of the car in each direction by combining the level meter with the odometer, and end the step.

In step S1, the tilt angle represents the tilt angle with respect to the horizontal plane. The setting range of the tilt angle can be -10° to 10° or -5° to 5°, etc. In this example, the setting range of the tilt angle is 0, that is, if the vehicle body tilts, it is considered that the vehicle is passing through a slope or a depression, so as to achieve accurate detection and reduce errors.

In step S2, if the pressure sensing value of the pressure sensor provided on the inner and outer wheels of the trolley suddenly changes to 0, it is considered that the trolley is in the air, and the moment when the pressure sensing value of the pressure sensor suddenly changes to 0 is regarded as the moment when the trolley is in the air.

As shown in Figures 6 and 7, the simulation calculation of the flying trajectory and landing coordinates of the car in step S3 first obtains the traveling direction θ ₁ of the car through the level meter, and obtains the flying angle θ ₀ formed by the car and the horizontal plane at the moment when the pressure sensor of the car suddenly changes to 0; and obtains the initial flying velocity v ₀ of the car at the moment of flying through the odometer set on the car. According to the parabola theorem, the following formula is obtained:

ΔZ′ ₂ = 0

Among them, Δs′ represents the calculated displacement distance of the car in the plane; Δy ₂ ′ represents the calculated displacement distance of the car in the plane in the Y direction of the spatial position coordinates; Δx ₂ ′ represents the calculated displacement distance of the car in the plane in the X direction of the spatial position coordinates; t′ represents the calculated time of the car falling back to the plane at the moment of taking off after taking off; g represents the acceleration of gravity. Among them, the calculated displacement distance of the plane represents the calculated displacement distance of the horizontal plane at the moment of taking off after the car takes off.

In order to ensure that there is no drop before and after the car leaves the ground and lands, the calculated time t' in the plane is compared with the actual time _t0 , where the actual time _t0 represents the length of time that the pressure sensor is continuously at 0. If | _tt0 | is less than the set threshold, it does not need to be corrected, and _Δy2 ', _Δx2 ' and ΔZ'2 are _directly substituted into the accumulated distance of the car in each direction; if | _tt0 | is greater than the set threshold, it is corrected according to the following formula:

Among them, Δy ₂ ^* represents the calculated distance of the vehicle's corrected displacement in the Y direction; Δx ₂ ^* represents the calculated distance of the vehicle's corrected displacement in the X direction; Δz ₂ ^* represents the calculated distance of the vehicle's corrected displacement in the Z direction. Substitute the corrected Δx ₂ ^* , Δy ₂ ^* , and Δz ₂ ^* into the accumulated distance traveled by the vehicle in each direction.

As shown in FIG8 , the travel distance of the car in each direction in step S5 is obtained by the aforementioned formula for calculating the travel distance of the car based on the Pythagorean theorem. The travel distance of the car in each direction is shown in the following formula:

Wherein, _Δy2 represents the distance traveled by the car in the Y direction; _Δx2 represents the distance traveled by the car in the X direction; _Δz2 represents the distance traveled by the car in the Z direction; _t1 represents the time taken for the pressure sensors on the inner and outer wheels to change from the flat ground pressure value on the flat ground to the non-flat ground pressure value and then back to the flat ground pressure value, or the time taken for the inclination angle of the level to change from zero to a non-zero value and then back to zero, where the flat ground pressure value is the pressure sensing value of the pressure sensor when the level is 0; _vt represents the speed of the car obtained by the odometer at time t; _θt represents the inclination angle sensed by the level at time t; _θ2t is the complementary angle of _θt .

The bump error elimination method is used to eliminate the flying error of the car during the odometer positioning process or the statistical process of the travel distance △l. The pressure sensor, odometer and level are combined to achieve accurate measurement of the car's mileage coordinate data.

The above description is only a specific example of the present invention and does not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and principle of the present invention, various modifications and changes in form and details may be made without departing from the principle and structure of the present invention, but these modifications and changes based on the idea of the present invention are still within the scope of protection of the claims of the present invention.

Claims (6)

1. The mileage calibration method of the railway engineering measurement trolley based on the positioning system is characterized by comprising the following steps of:

Step 1: the trolley judges whether the trolley is currently positioned in a tunnel or outside the tunnel according to the photosensitive value of a photosensitive sensor arranged on the trolley body; if the trolley is in the tunnel, entering a step 2; if the trolley is outside the tunnel, entering a step 5;

step 2: if the trolley is in the tunnel, judging whether the trolley is currently in a track or a non-track area according to pressure values sensed by pressure sensors respectively arranged on the inner wheel and the outer wheel of the trolley; if the trolley is in the trackless area, entering a step 3; if the trolley is on the track, entering a step 4;

step 3: the trolley is positioned in the tunnel and is not positioned on the track, a three-dimensional laser scanner is arranged on the trolley to realize modeling and positioning, scanning modeling coordinate data is obtained and is used as real-time coordinates of the trolley, and the step 1 is returned;

Step 4: the trolley is positioned in the tunnel and on the track, and the travelling distance is obtained by counting with an odometer arranged on the wheels of the trolley; obtaining mileage coordinate data through the travelling distance, taking the mileage coordinate data as a real-time coordinate of the trolley, and returning to the step 1;

Step 5: if the trolley is outside the tunnel, judging whether the received signal of the trolley can reach the set strength or not according to the signal value of the signal receiving equipment arranged on the trolley body; if the signal received by the trolley reaches the set signal intensity, the step 6 is entered; otherwise, enter step 7;

Step 6: when the received signal reaches the set signal intensity, the trolley realizes the coordinate data measurement of the trolley through a real-time dynamic carrier phase difference technology, obtains the differential positioning coordinates of the trolley, takes the differential positioning coordinates as the real-time coordinates of the trolley, and returns to the step 1;

step 7: if the signal received by the trolley does not reach the set signal intensity, judging whether the trolley is currently positioned on a track or in a non-track area according to the pressure values sensed by the pressure sensors respectively arranged on the inner and outer wheels of the trolley; if the trolley is in the trackless area, the step 8 is entered; if the trolley is on the track, entering a step 9;

In the calculation process of the mileage coordinate data and the travel distance, a bump error elimination method is adopted to eliminate or reduce the travel distance measurement error generated by the bump of the trolley; the bump error cancellation method includes the steps of:

Step S1: acquiring the inclination angle of the trolley by a level gauge arranged in the trolley; if the inclination angle exceeds the set range, the trolley is considered to pass through the sloping field or the depression, at the moment, the initial speed of the trolley corresponding to the inclination angle is obtained through the odometer, and the step S2 is carried out; if the inclination angle does not exceed the set range, the trolley is considered to be running on the flat ground, and the step S5 is carried out;

step S2: judging whether the trolley is emptied according to pressure sensors arranged on the inner wheel and the outer wheel; if the trolley is emptied, the step S3 is entered: otherwise, entering step S4;

step S3: the trolley vacates and passes over the sloping field or the depression, the pressure sensors arranged on the inner wheel and the outer wheel are combined through the level meter, the vacation angle and the vacation initial speed of the trolley at the vacation moment are obtained, the vacation track and the landing coordinates of the trolley are obtained through analog calculation, the travelling distance of the trolley is obtained according to the landing coordinates, and the step is finished;

Step S4: judging whether the trolley passes through the sloping field or the depression according to the trolley inclination angle obtained by the level meter, wherein if the inclination angle is larger than the maximum value of the set range, the trolley is considered to pass through the sloping field; if the inclination angle is smaller than the minimum value of the set range, the trolley is considered to pass through the depression; step S5 is entered;

Step S5: obtaining the travelling distance of the trolley in all directions by combining a level meter with an odometer, and ending the steps;

in the step S1, the inclination angle represents an inclination angle with respect to a horizontal plane;

In the step S2, if the pressure sensing value of the pressure sensor arranged on the inner and outer wheels of the trolley suddenly changes to 0, the trolley is considered to be emptied, and the moment when the pressure sensing value of the pressure sensor suddenly changes to 0 is taken as the moment when the trolley is emptied;

In the step S3, the simulated calculation of the vacation track and the landing coordinate of the trolley is carried out, firstly, the travelling direction theta ₁ of the trolley is obtained through a level meter, and the vacation angle theta ₀ formed by the trolley and the horizontal plane at the moment that the pressure sensor of the trolley suddenly changes to 0 is obtained; obtaining the initial speed v ₀ of the car at the moment of the car emptying through an odometer arranged on the car; according to the parabolic theorem, the following equation is obtained:

ΔZ′₂＝0

Wherein Δs' represents the calculated distance of the empty displacement of the trolley in the plane; Δy ₂' represents the in-plane vacation displacement calculation distance of the trolley in the Y direction in the spatial position coordinates; Δχ ₂' represents the in-plane vacation displacement calculation distance of the trolley in the X-direction in the spatial position coordinates; t' represents the vacation calculation time of the plane where the trolley falls back to the vacation moment after vacation; g represents gravitational acceleration; the in-plane vacation displacement calculation distance represents the displacement calculation distance of the horizontal plane where the trolley falls back to the vacation moment after being vacated;

To ensure that there is no drop before and after the trolley is lifted off and landed, the in-plane vacation calculation time t' is compared with the actual vacation time t ₀, wherein the actual vacation time t0 represents the length of time the pressure sensor is continuously 0; if |t-t ₀ | is smaller than the set threshold, the correction is not needed, and delta y ₂′、Δx₂' and delta Z ₂ are directly substituted into the running distance accumulation of the trolley in all directions; if |t-t ₀ | is greater than the set threshold, the correction is performed according to the following formula:

Wherein Δy ₂ ^* represents the calculated distance of the empty displacement of the trolley after the correction in the Y direction; Δx ₂ ^* represents the calculated distance of the empty displacement of the trolley after correction in the X direction; Δz ₂ ^* represents the calculated distance of the empty displacement of the trolley after correction in the Z direction; substituting the corrected Deltax ₂ ^*、Δy₂ ^* and Deltaz ₂ ^* into the running distance accumulation of the trolley in each direction;

The travelling distance of the trolley in each direction in the step S5 is obtained by calculating the travelling distance of the trolley based on Pythagorean theorem; wherein the travel distance of the trolley in each direction is shown as follows:

Wherein Δy ₂ represents the travel distance of the trolley in the Y direction; Δx ₂ denotes the travel distance of the trolley in the X direction; Δz ₂ represents the travel distance of the trolley in the Z direction; t ₁ represents the time that the pressure sensor on the inner and outer wheels changes from the level ground pressure value to the non-level ground pressure value and then changes to the level ground pressure value again, or the time that the inclination angle of the level changes from zero to a non-zero value and then returns to zero again, wherein the level ground pressure value is the pressure sensing value of the pressure sensor when the level is 0; v _t denotes the travelling speed of the trolley obtained by the odometer at time t; θ _t represents the inclination angle sensed by the level at time t; θ _2t is the complement angle of θ _t;

Step 8: the trolley is not on a track, an odometer arranged on a wheel of the trolley is combined with a three-dimensional laser scanner arranged on the trolley through a real-time dynamic carrier phase difference technology, the real-time position of the trolley is comprehensively judged, and the step 1 is returned;

In the step 8, the real-time dynamic carrier phase difference technology is combined with the odometer arranged on the wheel of the trolley and the three-dimensional laser scanner is arranged on the trolley, so that the real-time position of the trolley is comprehensively judged, and the method comprises the following steps:

Step 81: judging a time node t 'of a signal received by a primary trolley closest to the current time reaching a set signal intensity, and obtaining differential positioning coordinates (x' 1, y '1, z' 1) of the trolley by a real-time dynamic carrier phase differential technology corresponding to the time node;

Step 82: acquiring a travel distance Deltal acquired by an odometer in the current time from the time node t';

step 83: drawing a circle by taking differential positioning coordinates (x '1, y '1, z ' 1) as circle centers and the travelling distance Deltal as a radius; the range of the circular area represents the current position range of the trolley;

Step 84: judging the current time to obtain the size relation between the distance between the differential positioning coordinates (x 1, y1, z 1) of the trolley and the differential positioning coordinates (x '1, y'1, z '1) of the time node t' and the travelling distance Deltal through a real-time dynamic carrier phase differential technology; wherein if it is The differential positioning coordinates (x 1, y1, z 1) of the current time are used as real-time coordinates of the trolley; if it isScanning the obtained scanning modeling coordinate data (x 3, y3, z 3) by a three-dimensional laser scanner to serve as real-time coordinates of the trolley; ending the step;

step 9: the trolley is positioned on the track, and the real-time position of the trolley is comprehensively judged by combining the real-time dynamic carrier phase difference technology with the odometer arranged on the wheel of the trolley, and the step 1 is returned;

in the step 9, the real-time position of the trolley is comprehensively judged by combining a real-time dynamic carrier phase difference technology with an odometer arranged on a wheel of the trolley, and the method comprises the following steps:

step 91: judging a time node t 'of a signal received by a primary trolley closest to the current time reaching a set signal intensity, and obtaining differential positioning coordinates (x' 1, y '1, z' 1) of the trolley by a real-time dynamic carrier phase differential technology corresponding to the time node;

step 92: acquiring a travel distance Deltal acquired by an odometer in the current time from the time node t';

Step 93: drawing a circle by taking differential positioning coordinates (x '1, y '1, z ' 1) as circle centers and the travelling distance Deltal as a radius; the range of the circular area represents the current position range of the trolley;

Step 94: judging the current time to obtain the size relation between the distance between the differential positioning coordinates (x 1, y1, z 1) of the trolley and the differential positioning coordinates (x '1, y'1, z '1) of the time node t' and the travelling distance Deltal through a real-time dynamic carrier phase differential technology; wherein if it is The differential positioning coordinates (x 1, y1, z 1) of the current time are used as real-time coordinates of the trolley; if it isObtaining mileage coordinate data (x 2, y2, z 2) by an odometer of the trolley as real-time coordinates of the trolley; and (5) ending the step.

2. The method for calibrating the mileage of the railway engineering measurement trolley based on the positioning system according to claim 1, wherein the step 1 is characterized in that the step 1 is to judge whether the trolley is positioned in a tunnel or outside the tunnel according to the photosensitive change rate of the photosensitive sensor, set the parameter of the sensitivity as lambda, and take the photosensitive change rate delta lambda of a set time interval; the absolute value of the photosensitive change rate Δλ is compared with a set photosensitive change threshold Δλ ₀ as follows:

Wherein for the case that |Deltalambda| is less than or equal to Deltalambda ₀, if the state of the trolley in the time interval of the previous section is in the tunnel, the state of the trolley is kept in the tunnel; otherwise, if the state of the trolley in the time interval of the last section is out of the tunnel, the state of the trolley is kept out of the tunnel.

3. The method for calibrating mileage of a railroad engineering measurement car based on a positioning system according to claim 1, wherein the inner and outer wheels in the step 2 include an inner rail wheel and an outer rubber wheel, wherein the inner rail wheel is used for traveling on a rail, and the outer rubber wheel is used for traveling on the ground; the inner side rail wheel and the outer side rubber wheel are respectively provided with a pressure sensor, wherein if the pressure sensed by the pressure sensors on the outer side rubber wheel is larger than a set pressure value, the trolley is considered to travel in the rail-free area; and if the pressure sensed by the pressure sensor on the inner track wheel is larger than the set pressure value, the trolley is considered to travel on the track.

4. The method for calibrating the mileage of the railway engineering measurement trolley based on the positioning system according to claim 1, wherein in the step 3, the trolley performs space full-section non-contact scanning measurement on the space where the trolley is located through a three-dimensional laser scanner arranged on the trolley body; wherein marks are arranged at the mark points, and the marks are black-white alternate reflective cross targets or mark balls; the process of acquiring coordinate information by the three-dimensional laser scanner comprises the following steps: step 31: the trolley scans and acquires and stores the position information of the standard point through a three-dimensional laser scanner; wherein the method comprises the steps of

The position information of the calibration point comprises the space coordinates of the calibration point under the same space coordinate system or reference system and the point cloud data of the spectrum characteristics of the surface of the calibration point;

Step 32: the trolley scans and acquires space coordinates of other entities in space and a point cloud data set of the surface spectral characteristics of the space coordinates through a three-dimensional laser scanner;

step 33: the three-dimensional entity model of the space is obtained through point cloud splicing and filtering analysis;

step 34: obtaining scan modeling coordinate data (x 3, y3, z 3) of the target point through a calibration point in the three-dimensional solid model;

In step 34, the scan modeling coordinates are obtained relative to calibration points whose geographic locations are set in advance; and according to the geographic position of the target point, combining scanning modeling coordinate data of the target point relative to the target point to obtain the geographic position of the target point.

5. The method for calibrating the mileage of the railway engineering measurement trolley based on the positioning system according to claim 1, wherein in the step 4, the trolley obtains the traveling distance Δl and the traveling speed v through the odometer arranged on the wheels, obtains the traveling distance of the trolley in all directions by combining with the level meter arranged on the trolley, and obtains mileage coordinate data (x 2, y2, z 2) according to the accumulation of the traveling distances.

6. The method for calibrating the mileage of the railway engineering measurement car based on the positioning system according to claim 1, wherein the positioning of the real-time dynamic carrier-phase difference technique in the step 6 includes the steps of:

Step 61: the reference station transmits the observed value and the coordinate information of the measuring station to the mobile station in a related manner through a data link;

Step 62: the mobile station receives the observation value and the coordinate information of the station, and acquires satellite observation data through a satellite;

Step 63: the mobile station forms the received and collected data into a differential observation value to obtain differential positioning coordinates of the mobile station;

The rover in step 61 is a trolley.