Horizontal distance measurement system and method based on dual-row phase interferometric array

Abstract

The present application relates to the field of engineering surveying technology, and particularly relates to a horizontal distance measuring system and method based on a double-row phase interference array, a signal transmitting device for transmitting a measuring signal; a double-row receiving antenna array for receiving the measuring signal; a processing module connected with the double-row receiving antenna array; obtaining absolute slant ranges between the signal transmitting device and each antenna unit; obtaining vertical phase differences of the measuring signal; determining slant range differences between different antenna units; calculating a horizontal distance between a level gauge and a leveling rod; the present application firstly adopts a double-mode distance measuring mechanism which fuses absolute distance measurement and phase difference measurement, resolves the whole ambiguity through the absolute slant range, so as to determine the slant range differences between the antenna units; secondly, uses the horizontal phase difference generated by the double-row receiving antenna array to calculate the inclination of the leveling rod in real time, and compensates and corrects the measuring geometric model; finally, obtains the final horizontal distance through multiple calculation paths.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engineering surveying, and particularly relates to a horizontal distance measurement system and method based on a double-row phase interference array. BACKGROUND

[0002] Leveling is an important method of height measurement, with high precision and wide application. As one of the core tasks of engineering surveying, its precision is directly related to the reliability of terrain modeling, engineering construction and monitoring.

[0003] The core of leveling lies in using a horizontal line of sight as the basis for height transfer: a level establishes a horizontal line of sight parallel to the geoid, and the difference between the readings on the vertical leveling rods at the known elevation point (rear sight point) and the point to be measured (front sight point) is the height difference between the two points. The horizontal line of sight is crucial - it ensures that all readings are based on the same horizontal reference, making the height difference calculation unaffected by ground undulations or instrument position, thereby accurately transferring the height.

[0004] High-grade leveling has high requirements for the horizontal distance between the level and the front and rear leveling rods at each station. In order to eliminate the systematic effects of earth curvature, atmospheric refraction, and instrument collimation axis error on height measurement, it is necessary to first determine that the front and rear sight distances meet the corresponding grade specification requirements (such as GB / T 12898-2009 "National Third and Fourth Grade Leveling Specification", GB / T 12897-2006 "National First and Second Grade Leveling Specification") before measurement can be carried out.

[0005] In actual engineering, it becomes a key bottleneck restricting measurement efficiency and accuracy. In traditional operations, surveyors usually use the level to measure the distance, use a tape measure to measure, or use a distance measuring wheel to measure the distance to determine the distance between the instrument and the rod. Except for the level distance measurement, the other methods measure the approximate distance from the level to the level rod, which has a large error compared to the horizontal line of sight measurement. In addition, these methods, although low in cost, have the common defects of tedious operation process, inability to dynamically judge the equidistance of the double rods, low work efficiency, and susceptibility to external environmental interference.

[0006] In order to overcome the shortcomings of traditional methods, in recent years, the surveying and mapping field has attempted to introduce various technical innovations, such as using handheld laser range finders, portable electromagnetic wave distance measuring devices, and other non-contact measurement means to assist in distance control. To some extent, it has improved the convenience and accuracy of distance measurement, but usually still requires surveyors to perform multiple independent manual aiming, data reading and comparison calculations, and the degree of automation and integration is not high. In complex field operation environments such as strong light and signal obstruction, operation efficiency and reliability are still challenges. SUMMARY

[0007] The present application provides a horizontal distance measurement system and method based on a double-row phase interference array to quickly obtain the distance from the horizontal line of sight to the front and rear leveling rods in leveling measurement, achieve the purpose of equal front and rear sight distances, thereby improving the accuracy and efficiency.

[0008] The present application is realized by the following technical solutions:

[0009] A horizontal distance measurement system based on a double-row phase interference array comprises:

[0010] A signal transmitting device is arranged on a level gauge and used for transmitting a measurement signal;

[0011] A double-row receiving antenna array is symmetrically arranged on both sides of a leveling rod, and each row of the double-row receiving antenna array comprises a plurality of independent antenna units and is used for receiving the measurement signal;

[0012] A processing module is connected with the double-row receiving antenna array.

[0013] Optionally, the measurement signal comprises a pulse signal and a multi-frequency phase signal, the pulse signal is used for obtaining an absolute slant distance, and the multi-frequency phase signal is used for obtaining a vertical phase difference;

[0014] The processing module is used for:

[0015] Based on the measurement signals received by each antenna unit, the absolute slant distance between the signal transmitting device and each antenna unit is obtained;

[0016] Based on the measurement signals received by different antenna units, the vertical phase difference of the signals is obtained;

[0017] Based on the signals received by the antenna units at the same height of the leveling rod and respectively located on the two rows of the double-row receiving antenna array, the horizontal phase difference is obtained;

[0018] The vertical phase difference is de-blurred by using the absolute slant distance to determine the slant distance difference between different antenna units;

[0019] The inclination angle of the leveling rod is determined according to the horizontal phase difference;

[0020] The horizontal distance between the level gauge and the leveling rod is calculated based on the slant distance difference, and the calculation of the horizontal distance is corrected by using the inclination angle.

[0021] A horizontal distance measurement method based on a double-row phase interference array comprises:

[0022] A signal transmitting device transmits a measurement signal, and the measurement signal is received by a plurality of antenna units in a double-row receiving antenna array;

[0023] acquiring absolute slant ranges between the signal emitting device and each of the antenna elements ;

[0024] acquiring vertical phase differences of the measurement signals based on the measurement signals received by different antenna elements ;

[0025] using the absolute slant ranges to resolve ambiguities of the vertical phase differences , to determine slant range differences between different antenna elements ;

[0026] based on the absolute slant ranges and / or the slant range differences , calculating horizontal distances between the level meter and the leveling rod .

[0027] Further, the control method further comprises:

[0028] acquiring horizontal phase differences based on signals received by antenna elements at the same height of the leveling rod and respectively located on two rows of the double-row receiving antenna array ;

[0029] determining an inclination angle of the leveling rod according to the horizontal phase differences ;

[0030] correcting the horizontal distances using the inclination angle to obtain corrected horizontal distances .

[0031] Optionally, the method for acquiring absolute slant ranges comprises:

[0032] performing bidirectional ranging between the signal emitting device and the antenna elements, and recording multiple groups of transmission-reception time stamps during the round-trip propagation of signals between the two ;

[0033] calculating clock offsets between the signal emitting device and the antenna elements according to multiple groups of the transmission-reception time stamps ;

[0034] determining corrected one-way signal propagation times based on the measured signal flight times and using the clock offsets for compensation ;

[0035] using the corrected one-way signal propagation times ​multiplying a preset wave velocity , calculating the absolute slant range .

[0036] Optionally, the method for obtaining the vertical phase difference of the measurement signal comprises:

[0037] selecting at least two antenna units of the same row of the double-row receiving antenna array and located at different heights;

[0038] taking the difference between the phases of the measurement signals received by the two antenna units as the vertical phase difference, i.e. .

[0039] Optionally, the method for determining the slant range difference between different antenna units comprises:

[0040] calculating the absolute slant range difference based on the absolute slant range ;

[0041] calculating the true slant range difference containing the integer ambiguity of the vertical phase difference ;

[0042] determining the integer value of the integer ambiguity by comparing the absolute slant range difference and the true slant range difference ;

[0043] correcting the true slant range difference using the determined integer value of the integer ambiguity to obtain the slant range difference between different antenna units .

[0044] Optionally, the method for resolving the horizontal distance comprises:

[0045] generating multiple groups of independent candidate solutions of the horizontal distance by multiple different resolving methods ;

[0046] performing weighted fusion on the multiple groups of independent candidate solutions of the horizontal distance to obtain the final horizontal distance . ;

[0047] wherein the multiple different resolving methods comprise one or more of TOF direct resolving, phase difference chain resolving, and double-antenna cross resolving.

[0048] Optionally, the method for determining the inclination angle of the leveling rod according to the horizontal phase difference comprises:

[0049] ​​​The difference between the phases of the signals received by the antenna elements at the same height of the leveling rod and located on the two rows of the double-row receiving antenna array respectively is determined as the horizontal phase difference ;

[0050] Based on the determined horizontal phase difference, the wavelength of the measurement signal , and the preset interval between the two rows of the double-row receiving antenna array , the inclination angle is calculated through a trigonometric function relationship .

[0051] Optionally, the method for correcting the horizontal distance using the inclination angle comprises:

[0052] According to the inclination angle , the vertical height value used by the antenna elements in the geometric model is corrected to obtain an effective height value .

[0053] A horizontal displacement component caused by the inclination angle is introduced into the geometric model, and the geometric model is corrected to , and the horizontal distance is recalculated based on this.

[0054] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0055] The present application first adopts a dual-mode distance measuring mechanism that combines absolute distance measurement and phase difference measurement, analyzes the integer ambiguity of the absolute slant range, and thereby determines the slant range difference between the antenna elements; secondly, uses the horizontal phase difference generated by the double-row receiving antenna array to real-time calculate the inclination angle of the leveling rod, and compensates and corrects the measurement geometric model; finally, generates multiple sets of independent horizontal distance solutions through multiple solving paths, and performs weighted fusion to obtain the final horizontal distance.

[0056] The present application utilizes the high-precision characteristics of phase measurement of relative position, and can achieve millimeter-level distance measuring precision; through the arrangement of the double-row antenna array on the leveling rod and the combination of the weighted fusion strategy of multiple solving paths, it can effectively identify and suppress abnormal data introduced by complex environmental factors such as multipath effect, thereby enhancing the reliability and stability of the measurement results in complex field environments.

[0057] By using the horizontal phase difference to real-time calculate and correct the error caused by the inclination angle of the leveling rod, the measurement deviation caused by common problems in actual operation such as rod body inclination or uneven site can be effectively addressed, thereby improving the adaptability of the system to the operating environment and ensuring the measurement precision under non-ideal conditions. BRIEF DESCRIPTION OF DRAWINGS

[0058] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0059] Figure 1 is a flow chart of a horizontal distance measurement method based on a double-row phase interference array according to the present application.

[0060] Figure 2 is a structural schematic diagram of a horizontal distance measurement system based on a double-row phase interference array according to the present application.

[0061] Figure 3 is one of the shielding conditions of the horizontal distance measurement system according to the present application, the upper part of the shielding in the figure.

[0062] Figure 4 is one of the shielding conditions of the horizontal distance measurement system according to the present application, the lower part of the shielding in the figure.

[0063] Figure 5 is one of the shielding conditions of the horizontal distance measurement system according to the present application, the upper and lower parts of the shielding in the figure.

[0064] Reference signs: 1 - signal transmitting device, 2 - double-row receiving antenna array, 3 - level gauge, 4 - signal receiving device. DETAILED DESCRIPTION

[0065] In order to make the objects, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related content, rather than limit the present application.

[0066] In addition, it also needs to be explained that only the parts related to the present application are shown in the drawings for the convenience of description.

[0067] The embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0068] The traditional method has the following defects:

[0069] Low efficiency: the tape measurement needs to be repeated every time the station is changed, which is particularly cumbersome in the terrain with ups and downs or dense obstacles. For example, in hilly areas, the measurer needs to repeatedly clean the path and straighten the tape, and the single-station setting time may be more than 15 minutes.

[0070] Error accumulation: tape is easily affected by temperature and tension, and the ranging wheel is easy to slip on soft ground, resulting in a deviation in sight distance exceeding the specification limit (such as the requirement of four-level leveling that the sight distance difference be ≤3 m). Research shows that when the sight distance difference reaches 5 m, the height deviation caused by the i angle error can reach more than 2 mm at a distance of 100 m.

[0071] Susceptible to external environmental interference: in steep slopes, swamps or dense shrubs, manual tape may not be implemented.

[0072] These methods not only increase labor intensity, but also introduce systematic errors. Especially in the subway tunnel settlement monitoring and other scenarios that require sub-millimeter level of height accuracy, the imbalance of front and rear sight distance has become a prominent factor restricting data quality.

[0073] In order to overcome the shortcomings of traditional methods, in recent years, the surveying and mapping field has tried to introduce various technical innovations, although some progress has been made, but there are still obvious bottlenecks.

[0074] For example, using a handheld laser range finder, using phase laser ranging principle, the accuracy can reach millimeter level (such as ±1.5 mm / 30 m), which is significantly better than the tape. But the operation needs to aim at the front and rear scales respectively and manually calculate the distance difference, the process is not automatic, and the laser spot is difficult to identify in the environment with strong light during measurement, which prolongs the aiming time and makes it difficult to control the ranging accuracy.

[0075] Using laser-vision guided fusion method, combining monocular camera target recognition and laser automatic aiming technology, such as gradient self-focusing error compensation algorithm used in oblique plane airborne radar. In engineering surveying, such systems identify the scale barcode area through the camera, guide the laser beam to accurately irradiate the reflection area, realize "what you see is what you measure", and avoid manual aiming deviation. Experiments show that this method can shorten the aiming time to 2 seconds within 50 m, but the volume of such devices is too large, the mechanical structure is more, and the cost is too high, which also leads to the difficulty of using in production.

[0076] Using portable GNSS receivers and other positioning equipment, often because of high cost, slow solution speed, low positioning accuracy, and many obstacles in leveling affecting satellite signal reception, etc. lead to too many limitations.

[0077] In order to solve the above problems, portable electromagnetic wave ranging technology is introduced into the field of leveling. This technology is based on phase or pulse ranging principle, and the distance is calculated by modulating the time difference between the transmission and echo of electromagnetic waves, with an accuracy of ±(1-5 mm) and a range of 5 cm to 200 meters, with the advantage of non-contact measurement. Compared with traditional methods, its core breakthrough lies in three aspects:

[0078] Efficiency improvement: real-time ranging does not require manual tape, and the station setting time is shortened by more than 60%, especially suitable for long distance leveling routes;

[0079] Environment adaptability: In steep slope, forest and other field operations can quickly measure distance, avoid artificial back and forth walking distance measurement.

[0080] Intelligent integration: Modern devices embedded edge computing chips support GNSS positioning and multi-sensor fusion (such as inclination compensation), and real-time feedback the line-of-sight difference to the instrument screen through Bluetooth or LoRa protocol, automatically prompt to adjust the direction, realize the "measurement-computation-guidance" closed loop.

[0081] Embodiment one

[0082] The embodiment provides a horizontal distance measurement system based on a double-row phase interference array. From the overall architecture, the system introduces an electronic measurement component on the basis of the traditional "level 3 - level rod" measurement combination. The core components include a signal transmitting device 1 arranged at the measurement center point, a double-row receiving antenna array 2 arranged at the target point (i.e. the level rod), and a processing module for data processing and operation, which specifically includes the following components:

[0083] The signal transmitting device 1 is the signal source of the entire measurement system, which is arranged at the level 3 and can be integrated with the level 3 or attached to the level 3 as an independent module. The core function is to transmit a predetermined format of measurement signal to the direction of the level rod, and all distance solving is based on the reception and analysis of the measurement signal. The measurement signal includes a pulse signal and a multi-frequency phase signal. The pulse signal is used to obtain the absolute slant range, and the multi-frequency phase signal is used to obtain the vertical phase difference.

[0084] The double-row receiving antenna array 2 is symmetrically arranged on both sides of the level rod, which is taken as the axis of the center scale line of the level rod, and the two rows of antennas are mirror distributed. Each row of the double-row receiving antenna array 2 includes a plurality of independent antenna units. The antenna unit is a basic receiving element in the antenna array, each unit can independently receive and process signals, thereby providing signal samples from different spatial positions for the system, and simultaneously forming a vertical baseline (between different height units in the same row) and a horizontal baseline (between units of the same height in different rows) in space. The double-row multi-segment antenna can be used for segmented phase ranging and each unit can be independently ranged. If part of the antenna is blocked, the data of the antenna outside the blockage can be used for calculation, which is very suitable for field leveling operation and improves the ranging accuracy under the multiple support of multi-frequency antenna and redundant data (also TOA / TOF ranging).

[0085] The processing module is in data connection with the double-row receiving antenna array 2 through wired or wireless mode, and the core task is to receive the original signal data collected by each antenna unit in the array, and to perform processing algorithms including but not limited to signal synchronization, phase extraction, ambiguity resolution, distance calculation and error correction.

[0086] The overall working steps are: the signal is transmitted by the signal transmitting device 1, the different antenna units of the double-row receiving antenna array 2 receive the signal from their respective spatial positions, and transmit the signal data to the processing module, and the processing module is used for:

[0087] Based on the measurement signals received by each of the antenna units, the absolute slant range between the signal transmitting device 1 and each of the antenna units is obtained;

[0088] Based on the measurement signals received by different antenna units, the vertical phase difference of the signal is obtained;

[0089] Based on the signals received by the antenna units on the same height of the leveling rod and respectively located on the two rows of the double-row receiving antenna array 2, the horizontal phase difference is obtained;

[0090] The vertical phase difference is deambiguated using the absolute slant range to determine the slant range difference between different antenna units;

[0091] The inclination angle of the leveling rod is determined according to the horizontal phase difference;

[0092] Based on the slant range difference, the horizontal distance between the level 3 and the leveling rod is calculated, and the calculation of the horizontal distance is corrected using the inclination angle.

[0093] Specifically, the processing module comprises:

[0094] Central processing unit, FPGA parallel computing, for real-time calculation of phase difference, TOA / TOF distance, deambiguity, optimization solution, etc.;

[0095] Phase processing unit, for synchronous acquisition of phase values of all frequencies, etc., each channel is configured with: low noise amplifier (LNA) → mixer → phase detector (such as IQ demodulator);

[0096] Timing unit for TOA / TOF distance measurement;

[0097] Display for outputting front and rear rod horizontal distance, front and rear rod horizontal distance difference, leveling rod inclination angle, etc.

[0098] Communication unit for communication with the front and rear rod signal receiving device 4 through Bluetooth WIFI and other communication methods, and exchanging data;

[0099] The entire system also includes a battery unit for providing electrical energy.

[0100] For the convenience of description, it is assumed that the signal transmitting device transmits a continuous wave signal of a coherent frequency , a wavelength , usually a mixed frequency signal combining high and low frequencies, uses a continuous wave (CW) or frequency modulation continuous wave (FMCW) auxiliary anti-jamming, can overcome the limitations of a single frequency, and improves the performance, reliability and applicability of the distance measuring system.

[0101] The signal receiving device 4 is placed on the leveling rod and connected with the receiving antenna, and is mainly used to display the front and rear rod distance, inclination angle and other information, so that the rod setting personnel can quickly make adjustments. The single-side antenna is connected at the head and tail by N independent multi-frequency directional patch antennas (antenna units) with the same or different lengths, the distance between the head and tail adjacent antennas is , and the length of the whole single-side antenna is not greater than the length of the leveling rod; the two groups of single-side antennas are symmetrically arranged on both sides of the leveling code with the leveling code as the symmetric axis, and are arranged in parallel on both sides of the leveling code, and the distance between the two antennas is , and each antenna independently receives signals, and there are 2N channels.

[0102] The path difference is calculated by the phase difference of the signals in different antenna units, the phase ambiguity (integer period ambiguity) is solved by combining the multi-frequency signals, and then the horizontal distance and the instrument height are solved by a geometric model.

[0103] Embodiment two

[0104] The embodiment provides a method for measuring a horizontal distance based on the system in embodiment one, that is, a horizontal distance measurement method based on a double-row phase interference array. The method mainly and in parallel includes two core technologies: the first is "distance measurement", which aims to solve the horizontal distance; and the second is "attitude correction", which aims to measure and correct the error introduced by the non-ideal attitude (such as inclination) of the leveling rod. Finally, the result of the attitude correction will be used to calibrate the distance measurement result, so as to output the final horizontal distance.

[0105] The detailed steps of the method are as follows:

[0106] First step, signal transmission and reception.

[0107] The signal transmitting device transmits a measurement signal, and the measurement signal is received through a plurality of antenna units in the double-row receiving antenna array.

[0108] The signal transmitting device located on the level instrument transmits a predetermined measurement signal to the direction of the leveling rod provided with the double-row receiving antenna array.

[0109] Two rows of antennas are pasted on both sides of the scale code of the leveling rod, and each row of antennas is divided into N segments. The left and right antenna units at the same height form a horizontal baseline, and the antenna units in the vertical direction form a vertical baseline, forming a two-dimensional interference array.

[0110] Second step, obtaining absolute slant range.

[0111] Obtaining the absolute slant range between the signal transmitting device and each antenna unit .

[0112] After receiving the signal, the processing module first performs the first measurement calculation. The absolute slant range refers to the straight-line spatial distance from the signal transmitting device to the first antenna unit on the array, which is calculated by TOA (Time of Arrival) or TOF (Time of Flight) ranging method.

[0113] Third step, obtaining vertical phase difference.

[0114] Based on the measurement signals received by different antenna units, the vertical phase difference of the measurement signals is obtained .

[0115] The processing module performs the second measurement calculation. The vertical phase difference refers to the phase value difference of the same frequency signal received by two antenna units at different heights on the same row of antennas (such as unit and unit).

[0116] Fourth step, ambiguity resolution and slant range difference determination.

[0117] Using the absolute slant range , the vertical phase difference is deambiguated to determine the slant range difference between different antenna units ;

[0118] Fuse the data obtained in the first two steps: use the absolute slant range obtained by coarse measurement without ambiguity as a reference to analyze the integer ambiguity of the vertical phase difference obtained by fine measurement with ambiguity. Through this ambiguity resolution, the system can accurately calculate the slant range difference between different antenna units, i.e., the difference between the real spatial distances of the unit and the unit to the transmitting device.

[0119] Fifth step, preliminary horizontal distance calculation.

[0120] Based on the absolute slant range and / or the slope difference The horizontal distance between the level instrument and the leveling rod is calculated. .

[0121] To obtain accurate slope difference Then, combining the geometric models of each antenna element on the antenna array, the processing module can calculate a preliminary horizontal distance by solving a system of geometric equations. .

[0122] Step 6: Obtain the horizontal phase difference.

[0123] The horizontal phase difference is obtained based on the signals received by the antenna elements located at the same height as the leveling rod and on two rows of the dual-row receiving antenna array. ;

[0124] Horizontal phase difference refers to the difference in phase value of the same frequency signal received by two antenna elements located on the left and right rows of antennas at the same height on a leveling rod. The slight optical path difference between the two antenna elements and the transmitting device caused by the tilt of the leveling rod around its central axis results in the horizontal phase difference.

[0125] Step 7: Determine the inclination angle of the leveling rod.

[0126] According to the horizontal phase difference Determine the inclination angle of the leveling rod. ;

[0127] Based on known parameters such as the spacing between the two rows of antennas, the current tilt angle of the leveling rod is calculated using trigonometric functions.

[0128] Step 8: Correct and obtain the final horizontal distance.

[0129] Using the tilt angle The horizontal distance is corrected to obtain the corrected horizontal distance. .

[0130] The processing module uses the tilt angle calculated in step seven. The geometric model used in the fifth step to calculate the initial horizontal distance is modified (for example, the effective height of the antenna element is corrected and the horizontal displacement caused by tilt is introduced), and then the calculation is performed again to obtain a final horizontal distance after attitude error compensation.

[0131] Example 3

[0132] This embodiment describes in detail the specific method for obtaining the absolute slant range and vertical phase difference in the method described in Embodiment 2.

[0133] TOF ranging will be affected by clock non-synchronization between the transmitting end and the receiving end, resulting in errors. In order to overcome this problem, the embodiment adopts bidirectional ranging, measures and eliminates the clock offset between the two devices through a complete signal round trip (transmit -> receive -> transmit -> receive) process, so as to obtain an accurate signal one-way propagation time, and finally calculate the absolute slant range.

[0134] The basic model of TOF ranging is , wherein, is the speed of light, is the time of electromagnetic wave from the transmitting end to the receiving end.

[0135] In fact, the commonly used bidirectional ranging method eliminates the clock offset, assuming that in the first segment antenna unit, the signal generation time of the transmitting end is and records the time, the arrival time of the receiving end is and records the time, and the return signal time from the receiving end is , and the arrival time of the transmitting end is .

[0136] The specific method for obtaining the absolute slant range includes:

[0137] Bidirectional ranging is performed between the signal transmitting device and the antenna unit, and a plurality of groups of transceiving time stamps in the round trip propagation process between the two are recorded ;

[0138] is the time when the signal of the first unit is emitted from the transmitting device.

[0139] is the time when the signal arrives at the first unit.

[0140] is the time when the signal responds and sends back from the first unit.

[0141] is the time when the response signal of the first unit returns to the transmitting device.

[0142] According to a plurality of groups of the transceiving time stamps, the clock offset between the signal transmitting device and the antenna unit is calculated;

[0143] Based on the measured signal flight time , and using the clock offset for compensation, the corrected signal one-way propagation time is determined;

[0144] The corrected one-way propagation time of the signal Multiplied by the preset wave speed The absolute slope distance is calculated. .

[0145] When coherent signals emitted from the same signal source arrive at receiving points at different locations in space, their phases will differ due to the different propagation path lengths. Methods for obtaining the vertical phase difference of the signal include:

[0146] Select at least two antenna elements from the same row of the dual-row receiving antenna array, located at different heights, for example, the first... Unit and the unit.

[0147] The processing module extracts the frequencies received by the two antenna elements respectively. (corresponding wavelength is) The phase value of the measured signal and The fundamental relationship between the phase of a single signal and its propagation slant range is as follows: , in, This is the initial phase shift, which is independent of frequency.

[0148] The phase difference between the measurement signals received by the two antenna elements is taken as the vertical phase difference, i.e. .

[0149] Example 4

[0150] This embodiment describes in detail how the raw data (absolute slant range and vertical phase difference) obtained in Embodiment 3 are calculated and fused to obtain the preliminary horizontal distance.

[0151] Determine the slant range difference between the different antenna elements. The methods include:

[0152] The absolute slope distance difference is obtained based on the absolute slope distance calculation. ;

[0153] As can be seen from Example 3, the vertical phase difference Difference between slope distance and slope distance The following relationship exists between them: Based on the vertical phase difference Calculate the ambiguity including integers The true slope distance difference , For integer ambiguity.

[0154] Choose a frequency that corresponds to the equivalent wavelength. sufficiently large to ensure ambiguity-free. The integer value of the integer ambiguity is determined by comparing the absolute slant range difference and the true slant range difference : .

[0155] The integer value of the integer ambiguity is determined by comparing the absolute slant range difference and the true slant range difference ; represents taking the nearest integer.

[0156] The true slant range difference is corrected using the determined integer value of the integer ambiguity to obtain the true slant range difference between the different antenna elements .

[0157] In order to further improve the reliability and anti-interference ability of the final result, the embodiment does not use a single algorithm path to calculate the horizontal distance. Instead, multiple sets of independent horizontal distance "candidate solutions" are generated in parallel through multiple solving methods based on different physical principles or data combinations. Then, these candidate solutions are intelligently weighted and fused to obtain a final result that is much more stable and accurate than any single solution.

[0158] The method for solving the horizontal distance comprises:

[0159] A plurality of sets of independent candidate solutions of the horizontal distance are generated through a plurality of different solving methods ;

[0160] The plurality of different solving methods include one or more of TOF direct solving, phase difference chain solving, and double-antenna cross solving.

[0161] TOF direct solving: directly using the absolute slant range to calculate, the candidate solution obtained is For each antenna element , there are 2N independent solutions.

[0162] Phase difference chain solving: taking the absolute slant range of one antenna as the reference, using the true slant range difference to recursively calculate the slant range of other antennas, and then solving, the candidate solution obtained is . There are 2N-1 independent solutions.

[0163] The solving principle is roughly as follows:

[0164] A geometric equation set is constructed, the slant range model is known, and the ω influence is ignored: .

[0165] The slant range difference relationship is known, and the reference segment S1 is taken as the reference: .

[0166] The slant range difference relationship is brought into the slant range model, and the following is obtained: , and the simultaneous equations are eliminated to obtain: .

[0167] The residual error equation can be obtained from the above formula: .

[0168] By means of the nonlinear optimization algorithm (Levenberg-Marquardt algorithm), the variables and are optimized by minimizing the objective function .

[0169] Let , be the initial values, where is the estimated reference horizontal distance: .

[0170] The optimal solution , is brought into the slant range model, and the horizontal distance D is obtained: .

[0171] The double-antenna cross-solution utilizes the signals of the left and right antenna units at the same height to obtain candidate solutions , and there are N independent solutions. is the slant range of the left antenna, is the slant range of the right antenna.

[0172] The multiple groups of independent horizontal distance candidate solutions are weighted and fused to obtain the final horizontal distance ; is the weight of the i-th candidate solution .

[0173] Using the weighted average method, assuming that there is no outlier (Litter rule to remove outliers), Q (Q=2N+(2N-1)+N=5N-1) final horizontal distances can be obtained.

[0174] Different horizontal distance solving groups are assigned weights, as shown in the following table.

[0175] Table 1 Weight table of different horizontal distance solving groups

[0176]

[0177] Example Five

[0178] This embodiment describes in detail the measurement and correction process of the inclination angle used to improve the measurement accuracy under complex working conditions in the method of the application.

[0179] The double-row antenna array structure of the present application can accurately perceive the inclination of the leveling rod relative to the measuring line of sight by comparing the slight difference in phase of signals received by the left and right rows of antennas.

[0180] The specific method for determining the inclination of the leveling rod based on the horizontal phase difference comprises:

[0181] The difference between the phases of signals received by the antenna units at the same height of the leveling rod and located in the two rows of the double-row receiving antenna array is determined as the horizontal phase difference . , is the antenna unit in the left row, is the antenna unit in the right row. The slight path difference between the left and right antennas and the signal transmitting device .

[0182] Based on the determined horizontal phase difference, the wavelength of the measuring signal , and the preset distance between the two rows of the double-row receiving antenna array , there is a trigonometric relationship , and the inclination is calculated based on the above relationship .

[0183] Since the antenna array of the present application has multiple groups of units in the vertical direction, a series of inclinations can be calculated . By comparing the inclination values at different heights, the detection of whether the rod body itself is bent can also be realized, for example, when is greater than a preset threshold ( ), the system can issue a rod body deformation warning.

[0184] Then, the inclination is used to correct the horizontal distance, correct the projection height of the antenna unit in the vertical direction, and compensate for the additional displacement of the antenna unit in the horizontal direction due to the inclination. The specific method comprises:

[0185] When the leveling rod is inclined by an angle, the effective projection height of an antenna unit with an original height of in the direction perpendicular to the horizontal line of sight will be shortened, i.e., according to the inclination , the vertical height value used in the geometric model of the antenna unit is corrected to obtain the effective height value .

[0186] In a more precise model, a pre-calibrated calibration parameter , can also be introduced.

[0187] Standard slant distance geometric model is based on the ideal case that all antenna elements are located on a vertical line. When the leveling rod is tilted, the antenna elements not only change in vertical height, but also produce a horizontal displacement away from the center line, which is about , the horizontal displacement component caused by the tilt angle is introduced into the geometric model, and the geometric model is revised to Based on this revised model, the processing module re-solves the horizontal distance to obtain the final horizontal distance and re-solves the horizontal distance based on it.

[0188] Embodiment Six

[0189] This embodiment provides a specific application example in a real non-ideal measurement environment to illustrate the complete workflow and technical effects.

[0190] Suppose in a high-level leveling operation, the leveling instrument is placed at a station, and the initial absolute distance from the front and rear leveling rods is about 50 meters. There are metal guardrails near the leveling rods, which easily cause multipath interference of the signal; at the same time, there are slight obstacles in the line of sight of the observer, which may cause some antenna elements to be blocked. In this scenario, the front rod is measured to have a tilt angle of The temperature and humidity conditions during the operation are suitable.

[0191] The following will take the distance measurement of the front-view leveling rod as an example to explain the specific application process of the method step by step. This process can refer to the system and various blocking conditions shown in Figures 2 to 5 .

[0192] (1) First, the measurement personnel place the leveling instrument on the station according to the conventional leveling requirements, and set the front and rear leveling rods on the known point and the point to be measured, respectively, as shown in Figure 2 . Then, start the signal transmitting device on the leveling instrument and the signal receiving and processing system on the leveling rod.

[0193] (2) The operator aims the leveling instrument at the front-view leveling rod and starts the measurement program. At this time, the processing module will perform a multi-path, multi-dimensional data acquisition and fusion solving process:

[0194] (a) Multi-path parallel computing and data acquisition are executed simultaneously to perform multiple solving to generate a set of independent candidate solutions.

[0195] TOF direct solving path: the system first obtains an initial absolute slant range by measuring the time of flight (TOF) of the signal. However, due to the multipath reflection interference of the metal guardrails, the measurement result of this path is contaminated, for example, an abnormal value of 50.127 meters containing a +12 centimeter error is measured.

[0196] Phase difference chain solution path: At the same time, the system performs phase difference solution on the received signals. By using the aforementioned TOF value to solve the ambiguity, the system obtains high-precision slant range difference between antenna units. Based on this, through chain recursion, the system calculates another horizontal distance candidate solution.

[0197] Dual-antenna cross solution path: Using the signals of the left and right units of the dual-row antenna at the same height, the system performs cross solution with strong anti-dip interference capability and obtains a third independent horizontal distance candidate solution.

[0198] (b) Dip angle calculation and model correction: At the same time as the above calculation, the system calculates the current dip angle of the leveling rod in real time using the horizontal phase difference as . This dip angle parameter is used to correct the geometric model relied on in all solution paths, thereby compensating for the error caused by the inclination of the rod body.

[0199] (c) Data fusion and final output: The fusion algorithm in the processing module analyzes all the candidate solutions generated above. It identifies that the 50.127 meters obtained by the TOF direct solution path is an outlier caused by multipath effect and is excluded or given a very low weight in the final weighted average calculation. Subsequently, the algorithm performs weighted fusion on other candidate solutions with high reliability (such as phase difference chain solution and cross solution) and outputs the forward horizontal distance: D1 = 50.012 ± 0.004 meters.

[0200] (3) Back rod distance solution: In the same way, the system measures and solves the horizontal distance D2 between the leveling instrument and the back leveling rod.

[0201] Sight distance difference calculation and adjustment: The processing module automatically calculates the front-back sight distance difference and displays the result in real time to the operator. The operator adjusts the position of the front rod or the back rod according to the displayed difference until the corresponding leveling measurement level specification requirements are met (e.g., less than 1 meter).

[0202] Station reset: If the leveling rod position adjustment cannot meet the sight distance difference requirements, the system will prompt the operator to move the leveling instrument to a new position, and then repeat steps (1) to (3) until the sight distance is balanced.

[0203] In the present application, TOF is used to provide an absolute distance reference and constrain phase difference solution ambiguity; phase difference is used to provide high-precision relative correction and improve TOF accuracy; and dual-row antenna is used to provide dip angle compensation and spatial diversity.

[0204] In combination with Embodiments 1 to 5, the present application has the following advantages:

[0205] (1) Hardware topology innovation (double-row 2N-section antenna) → Realize spatial dense sampling and inclination layer perception.

[0206] (2) Signal coordination design (TOA + phase difference joint transmission) → Achieve centimeter-level reference and millimeter-level correction.

[0207] (3) Algorithm fusion architecture (5N-1 weighted fusion) → Break through the bottleneck of single-point error and multipath interference.

[0208] (4) Real-time parallel processing (FPGA full-channel calculation) → Complete 100 times efficiency leap.

[0209] Finally, four core achievements are realized:

[0210] (1) Millimeter-level accuracy (±4mm / 100m), expected results as follows:

[0211] Table 2 Comparison of expected results

[0212]

[0213] (2) Large inclination tolerance (≤5° without precision reduction), anti-interference effect as follows:

[0214] Table 3 Comparison of anti-interference effects

[0215]

[0216] (3) Stability in complex environment (multipath suppression ratio >25dB), environment adaptability comparison as follows:

[0217] Table 4 Comparison of environment adaptability

[0218]

[0219] (4) Second-level automatic measurement (<0.5s / point), efficiency improvement comparison as follows:

[0220] Table 5 Comparison of efficiency improvement

[0221]

[0222] In the description of the specification, the description of the terms "one embodiment / way", "some embodiments / ways", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In the description of the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments / ways or examples. In addition, the person skilled in the art can combine and combine the different embodiments / ways or examples described in the specification and the features of the different embodiments / ways or examples, without contradiction.

[0223] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0224] The person skilled in the art should understand that the above-mentioned embodiments are only for the purpose of clearly illustrating the present application, and are not intended to limit the scope of the present application. For those skilled in the art, other changes or modifications can be made on the basis of the above-mentioned application, and these changes or modifications are still within the scope of the present application.

Claims

1. A horizontal distance measurement system based on a dual-row phase interferometric array, characterized in that, include: A signal transmitting device (1) is installed on the level (3) and is used to transmit measurement signals; A dual-row receiving antenna array (2) is symmetrically arranged on both sides of the leveling rod, and each row of the dual-row receiving antenna array (2) includes multiple independent antenna elements for receiving the measurement signal; A processing module, which is connected to the dual-row receiving antenna array (2); The measurement signal includes a pulse signal and a multi-frequency phase signal. The pulse signal is used to obtain the absolute slant range, and the multi-frequency phase signal is used to obtain the vertical phase difference. The processing module is used for: Based on the measurement signals received by each of the antenna elements, the absolute slant distance between the signal transmitting device and each of the antenna elements is obtained; The vertical phase difference of the signal is obtained based on the measurement signals received by different antenna elements; The horizontal phase difference is obtained based on the signals received by the antenna elements at the same height as the leveling rod and located on two rows of the dual-row receiving antenna array. The absolute slant range is used to de-ambiguate the vertical phase difference in order to determine the slant range difference between different antenna elements. The inclination angle of the leveling rod is determined based on the horizontal phase difference; Based on the slope difference, the horizontal distance between the level instrument and the leveling rod is calculated, and the calculation of the horizontal distance is corrected using the inclination angle.

2. A horizontal distance measurement method based on a dual-row phase interferometer array, characterized in that, include: The signal transmitting device transmits measurement signals and receives the measurement signals through multiple antenna elements in a dual-row receiving antenna array; Obtain the absolute slant distance between the signal transmitting device and each antenna element; The method for obtaining the absolute slant range includes: performing bidirectional ranging between the signal transmitting device and the antenna element, and recording multiple sets of transmit and receive timestamps during the round-trip propagation of the signal between the two; calculating the clock offset between the signal transmitting device and the antenna element based on the multiple sets of transmit and receive timestamps; determining the corrected one-way propagation time of the signal based on the measured signal flight time and by compensating for the clock offset; and multiplying the corrected one-way propagation time of the signal by a preset wave velocity to calculate the absolute slant range. The vertical phase difference of the measurement signals is obtained based on the measurement signals received by different antenna elements. The method for obtaining the vertical phase difference includes: selecting at least two antenna elements in the same row of the dual-row receiving antenna array and located at different heights; and taking the phase difference of the measurement signals received by the two antenna elements as the vertical phase difference. The slant range difference between different antenna elements is determined by deambiguing the vertical phase difference using absolute slant range. The method for determining the slant range difference includes: calculating the absolute slant range difference using the absolute slant ranges of different antenna elements; calculating the true slant range difference including integer ambiguity based on the vertical phase difference of the corresponding antenna elements; comparing the absolute slant range difference and the true slant range difference to determine the integer value of the integer ambiguity; and correcting the true slant range difference using the determined integer value of the integer ambiguity to obtain the slant range difference between the different antenna elements. Based on the absolute slope range and / or slope range difference, the horizontal distance between the level and the leveling rod is calculated. The method for calculating the horizontal distance includes: generating multiple independent candidate solutions for the horizontal distance through various different calculation methods; and weightedly fusing the multiple independent candidate solutions for the horizontal distance to obtain the final horizontal distance. Among these, the various different calculation methods include one or more of the following: TOF direct calculation, phase difference chain calculation, and dual-antenna cross calculation.

3. The horizontal distance measurement method based on a dual-row phase interferometric array according to claim 2, characterized in that, Also includes: The horizontal phase difference is obtained based on the signals received by the antenna elements at the same height as the leveling rod and located on two rows of the dual-row receiving antenna array. The inclination angle of the leveling rod is determined based on the horizontal phase difference; The horizontal distance is corrected using the tilt angle.

4. The horizontal distance measurement method based on a dual-row phase interferometer array according to claim 3, characterized in that, The method for determining the inclination angle of the leveling rod based on the horizontal phase difference includes: The phase difference between the signals received by the antenna elements at the same height on the leveling rod and located on the two rows of the double-row receiving antenna array is defined as the horizontal phase difference. Based on the determined horizontal phase difference, the wavelength of the measured signal, and the preset spacing between the two rows of the dual-row receiving antenna array, the tilt angle is calculated using a preset trigonometric function relationship.

5. The horizontal distance measurement method based on a dual-row phase interferometric array according to claim 3, characterized in that, The method for correcting the horizontal distance using the tilt angle includes: Based on the tilt angle, the vertical height value used by the antenna element in the geometric model for calculating the horizontal distance is corrected to obtain an effective height value; The horizontal displacement component caused by the tilt angle is introduced into the geometric model, and the horizontal distance is recalculated based on the effective height value and the horizontal displacement component.

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