Satellite internet high-reliability positioning communication method and system in construction process

Abstract

The present application relates to the technical field of satellite communication, in particular to a satellite internet high-reliability positioning communication method and system in construction process. The present application firstly acquires differential positioning data packets, solves the approximate coordinate geometric line-of-sight distance of construction machinery, then compares the phase observation distance and the geometric line-of-sight distance to obtain the ranging deviation; further, according to the change of the phase observation distance between the current adjacent epochs, the Doppler observation speed is compared, combined with the difference between the elevation angle of the satellite and the maximum shielding elevation angle, the Doppler usable state is determined; further, for the satellite with unavailable Doppler, the deviation trend parameter of the ranging deviation is extracted and the degradation flag is updated; finally, according to the Doppler usable state of each satellite, a preset reconstruction mode is selected, the reconstructed phase observation value is obtained, and encapsulation and transmission are carried out, so as to ensure the stability and precision of satellite positioning communication in complex construction environment.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, specifically to a highly reliable satellite internet positioning and communication method and system during construction. Background Technology

[0002] In open-pit mining, deep foundation excavation, and infrastructure construction in canyon areas, engineering teams increasingly favor low-Earth orbit (LEO) satellite internet as the backhaul link for differential positioning data due to the often-existing coverage blind spots or unstable signals of terrestrial public communication networks. However, the complex forwarding mechanism of LEO satellite communication systems inevitably introduces random transmission delay jitter into the differential data packets arriving at the field gateway, disrupting the strict time synchronization between the rover and base station observation data. To ensure the computational requirements of high-precision RTK positioning, it is typically necessary to extrapolate the lagging differential data using Doppler observations to compensate for transmission delays.

[0003] Existing time delay compensation methods are typically based on the assumption that Doppler frequency shift accurately reflects the rate of change of line-of-sight distance. However, in environments with strong multipath propagation, such as deep pits and rock walls, reflected signals can interfere with the receiver's tracking loop, resulting in inaccurate radial velocity components in Doppler observations. In this scenario where "time delay compensation" and "multipath effect" are coupled, directly using contaminated Doppler data for long-term extrapolation will amplify instantaneous velocity errors into distance errors, causing the reconstructed carrier phase to deviate from the true value. This makes it difficult to generate continuous and accurate differential observation data, thus failing to meet the high reliability requirements of construction machinery. Summary of the Invention

[0004] To address the technical problem of obtaining accurate reconstructed phase observations in complex construction environments due to the coupling of satellite communication link delay jitter and on-site multipath effects, this invention aims to provide a highly reliable satellite internet positioning communication method and system during construction. The specific technical solution adopted is as follows: A highly reliable satellite internet positioning communication method during construction, the method comprising: Acquire differential positioning data packets transmitted via low-Earth orbit satellite links. For each current satellite: calculate the approximate coordinates of the construction machinery based on pseudorange observations and satellite ephemeris, and calculate the geometric line-of-sight distance; compare the phase observation distance with the geometric line-of-sight distance to obtain the ranging deviation. Based on the changes in the phase observation distance between adjacent epochs, the Doppler observation velocity is compared, and the difference between the satellite's elevation angle and the maximum obstruction elevation angle is considered to determine the Doppler availability status. The extrapolation span is calculated based on the data generation time and the preset target time. For satellites where Doppler is unavailable, the deviation trend parameters are extracted from the historical ranging deviation sequence and the degradation flag is updated. Based on the deviation trend parameters, the extrapolation span, the approximate coordinates, and the status of the degradation flag, a preset reconstruction mode is selected according to the Doppler availability status of each satellite to obtain reconstructed phase observation values, which are then encapsulated and transmitted.

[0005] Furthermore, the preset reconstruction modes include velocity integral mode, geometric trend synthesis mode, and degradation mode.

[0006] Furthermore, the method for selecting the preset reconstruction mode includes: When the satellite is determined to be Doppler available, the velocity integration mode is selected; when the satellite is determined to be Doppler unavailable: if the degradation flag is invalid, the geometric trend synthesis mode is selected; if the degradation flag is valid, the degradation mode is selected.

[0007] Furthermore, the method for obtaining the reconstructed phase observations includes: For each satellite currently in use: when the velocity integration mode is selected, the current phase observation distance is linearly extrapolated using the Doppler observation velocity and the extrapolation span to obtain the initial reconstruction value; When the geometric trend synthesis mode is selected, the predicted coordinates of the satellite at the preset target time are compared with the approximate coordinates to obtain the theoretical geometric line-of-sight distance. The theoretical geometric line-of-sight distance is linearly extrapolated using the deviation trend parameter and the extrapolation span to obtain the initial reconstruction value. When the degradation mode is selected, the phase observation distance is used as the initial reconstruction value of the preset target time; Based on the switching of the preset reconstruction mode, the deviation value in the register is updated, and the initial reconstruction value and the deviation value are fused to obtain the reconstructed phase observation value.

[0008] Furthermore, the method for determining the Doppler availability state includes: For each satellite currently in use: obtain the rate of change of the phase observation distance between the current epoch and the adjacent previous epoch, as the phase difference velocity; obtain the velocity deviation based on the difference between the phase difference velocity and the Doppler observation velocity; obtain the terrain occlusion factor based on the difference between the satellite's elevation angle and the maximum occlusion elevation angle. Based on the velocity deviation and the terrain occlusion factor, the Doppler availability status of each satellite is determined.

[0009] Furthermore, the method for determining the current Doppler availability status of each satellite based on the velocity deviation and the terrain occlusion factor includes: When the velocity deviation is greater than a preset velocity consistency threshold, or the terrain occlusion factor is greater than a preset terrain risk threshold, the satellite is determined to be Doppler unavailable; when the velocity deviation is less than or equal to the preset velocity consistency threshold, and the terrain occlusion factor is less than or equal to the preset terrain risk threshold, the satellite is determined to be Doppler available.

[0010] Furthermore, the method for specifying the deviation trend parameter includes: The deviation trend parameters include the shift rate and intercept of the fitted straight line of the historical sequence of the ranging deviation.

[0011] Furthermore, the fitted straight line is obtained using a random sampling consensus algorithm.

[0012] Furthermore, the method for updating the degradation flag includes: Within the historical sequence of ranging biases, points where the residual from the sample point to the fitted straight line is less than a preset tolerance threshold are marked as inliers. When the proportion of inliers to all sample points is less than a preset inlier proportion threshold, or the total number of sample points is less than a preset regression threshold, the degradation flag is updated to be valid.

[0013] The present invention also proposes a high-reliability satellite internet positioning and communication system during construction, the system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the steps of the high-reliability satellite internet positioning and communication method during construction.

[0014] The present invention has the following beneficial effects: This invention first acquires differential positioning data packets, calculates the approximate coordinates and geometric line-of-sight distance of the construction machinery, and then compares the phase observation distance and the geometric line-of-sight distance to obtain the ranging deviation. This physically eliminates macroscopic distance changes caused by satellite orbital motion, providing a direct input basis for subsequent multipath detection and data reconstruction based on error signal characteristics. Furthermore, based on the changes in phase observation distance between adjacent epochs, it compares the Doppler observation velocity and, combined with the difference between the satellite's elevation angle and the maximum obstruction elevation angle, determines the Doppler availability status, accurately identifying Doppler velocity anomalies caused by deep pit multipath effects, ensuring the physical authenticity of the reconstructed data. For satellites with unavailable Doppler, it extracts the deviation trend parameters of the ranging deviation and updates the degradation flag. Finally, based on the Doppler availability status of each satellite, it selects a preset reconstruction mode, performs adaptive strategy switching, obtains reconstructed phase observation values, ensures the accuracy and continuity of the output observation data, and encapsulates and transmits the data. This invention extracts ranging errors by solving approximate coordinates, and determines the Doppler availability status by combining phase change rate, Doppler observation, and obstruction elevation angle. Under the coupling of multipath and satellite link time delay, it generates highly reliable phase observation values, ensuring the stability and accuracy of satellite positioning communication in complex construction environments. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A flowchart illustrating a highly reliable satellite internet positioning and communication method during construction, as provided in one embodiment of the present invention; Figure 2 A flowchart illustrating a method for obtaining deviation trend parameters, provided as an embodiment of the present invention. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a high-reliability satellite internet positioning and communication method and system during construction, based on the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] The following description, in conjunction with the accompanying drawings, details a specific scheme for a high-reliability satellite internet positioning and communication method and system during construction provided by this invention.

[0020] Please see Figure 1 The document illustrates a flowchart of a high-reliability satellite internet positioning and communication method during construction, provided by an embodiment of the present invention, specifically including: Step S1: Obtain the differential positioning data packet transmitted via the low-orbit satellite link. For each current satellite: calculate the approximate coordinates of the construction machinery based on pseudorange observations and satellite ephemeris, and calculate the geometric line-of-sight distance; compare the phase observation distance and the geometric line-of-sight distance to obtain the ranging deviation.

[0021] In one embodiment of the invention, the system monitors UDP or TCP data streams from low-Earth orbit (LEO) satellite communication terminals (such as Starlink user terminals or other LEO constellation terminals) in real time via the gateway's network interface. The system captures differential data packets compliant with the RTCM (Radio Technical Commission for Maritime Services) standard transmitted via the LEO satellite link.

[0022] The moment the data packet arrives at the gateway kernel protocol stack, the system reads the system time maintained by the local high-precision oscillator and records the physical arrival time of the data packet. Subsequently, the system parses the application layer header of the data packet to extract the data generation time stamped by the base station or satellite at the moment of signal transmission / generation. This time is usually represented as GPS Week Seconds or a UTC timestamp.

[0023] Data generation time With physical arrival time Reflecting the current communication transmission latency , This is used for real-time monitoring of link congestion. The local clock of the edge gateway needs to be synchronized with the GPST satellite time system via NTP or GNSS timing.

[0024] Before data analysis and reconstruction, in order to meet the requirements of downstream positioning and calculation equipment (such as RTK boards) for strictly equal-interval sampling of input data (e.g., 1Hz, 5Hz, or 10Hz), the system calculates the next upcoming sampling hour based on the preset sampling rate, and uses this as the preset target hour. Time-domain alignment is performed based on a preset target time. For example, if the sampling interval is seconds (10Hz), and Seconds, then the system will Set as Seconds. All subsequent data reconstruction operations will be performed based on this. The simulation is performed with the endpoint in mind.

[0025] Because different satellite navigation systems (such as GPS, BDS, and Galileo) have different definitions of their original observations, the system needs to map them uniformly to physical metric space. The system parses the data packet... Raw carrier phase observations of the satellite (Unit: Week) and the original Doppler frequency shift observations (Unit: Hz).

[0026] The system utilizes the first The carrier wavelength of the signal frequency corresponding to each satellite (e.g., GPS L1 band) Adjustments will be made to the following (meters): Phase observation distance (Unit: meters): Phase observation distance characterizes the comprehensive distance between the satellite and the receiver, including geometric distance, receiver clock error, atmospheric delay, multipath error, and integer ambiguity.

[0027] Doppler observation speed (Unit: meters per second): The negative sign is introduced here because a positive Doppler frequency shift indicates that the satellite and receiver are relatively close (distance decreases), and velocity is defined as the rate of change of distance. Doppler observation velocity characterizes the line-of-sight relative velocity between the satellite and receiver, and also includes the frequency shift component caused by receiver clock drift.

[0028] In order to accurately isolate the influence of satellite orbital motion on the observation distance in subsequent steps, the system needs to know the approximate current position of the construction machinery as a reference point. Therefore, the approximate coordinates of the construction machinery are calculated based on pseudorange observations and satellite ephemeris. Subsequently, the geometric line-of-sight distance is calculated based on the approximate coordinates, representing the theoretical propagation path under ideal error-free conditions. Then, the phase observation distance and the geometric line-of-sight distance are compared to obtain the ranging deviation. This physically eliminates the macroscopic distance changes caused by satellite orbital motion, allowing the residual ranging deviation sequence to clearly reveal the composite error dynamics composed of environmental factors such as receiver clock bias, atmospheric delay, and multipath effects. This transforms the original, mixed observations into a purer error signal, providing a direct input basis for subsequent multipath detection and data reconstruction based on the error signal characteristics.

[0029] Preferably, in one embodiment of the present invention, considering that the system may be in a cold start phase or that downstream RTK devices may lose lock due to signal blockage and be unable to provide feedback position, the system has a built-in independent single-point positioning (SPP) calculation function: The system extracts the first data packet from the data packet. pseudorange observations of satellites (Code Pseudorange). Simultaneously, the system decodes the satellite broadcast ephemeris (satellite ephemeris) broadcast along with the path and calculates the data generation time. Position coordinates of each satellite in the geocentric-ground-fixed coordinate system (ECEF) and satellite clock bias .

[0030] Construct the pseudorange observation equations: ; In the formula, The approximate coordinates of the machine to be solved , The receiver clock error to be solved is... At the speed of light, For residual error, , This represents the current number of satellites.

[0031] The system employs the well-known weighted least squares method to iteratively solve the pseudorange observation equations, thereby calculating the approximate coordinates of the construction machinery. After calculating a set of approximate coordinates, these are used as the locked coordinates and remain unchanged for a preset locking period (e.g., 5 minutes). When the locking period ends, the calculation is repeated and the locked coordinates are updated.

[0032] In other embodiments of the present invention, the implementer may also set a coordinate mutation threshold, such as 20 meters, to calculate a set of approximate coordinates as the locked coordinates. In subsequent epochs, SPP calculation is continuously performed in the background to obtain real-time coordinates, and the distance between the real-time coordinates and the locked coordinates is calculated. If the distance is less than the coordinate mutation threshold, the locked coordinates are continued to be used; if the distance is greater than the threshold, the locked coordinates are updated to the current approximate coordinates, and the historical data buffer is reset.

[0033] It should be noted that if the current number of satellites is less than 4, the equations cannot be solved. In this case, the system will directly use the approximate coordinates of the construction machinery obtained from the previous epoch as the current coordinates. If the system is in the cold start phase and has no historical coordinates, it is marked that the current epoch cannot establish a baseline, and the system enters a waiting state or only performs data pass-through; the solution process of the equation system is a well-known technique and will not be described in detail.

[0034] In this embodiment, the approximate coordinates calculated are only used as linearization reference points for subsequent calculations of geometric line-of-sight distance, and not the final positioning result. In deep pit multipath environments, approximate coordinates calculated based on pseudorange may have absolute positioning errors on the order of meters or even tens of meters. However, since navigation satellite orbital altitudes are typically above 20,000 kilometers, the directional change in the satellite line-of-sight vector caused by a ten-meter error in the receiver's ground position is extremely small (usually within...). (Radian scale). According to the principle of geometric projection, the effect of such a small directional deviation on the projection of the rate of change of geometric distance (i.e., line-of-sight velocity) is negligible, thus meeting the requirements of this system as a linearization reference.

[0035] Calculate the data generation time based on satellite ephemeris. No. Precise orbital position of the satellite Combined with the calculated approximate coordinates The geometric line-of-sight distance from the satellite to the phase center of the construction machinery antenna is obtained. , , This indicates taking the Euclidean distance.

[0036] Finally, from the phase observation distance Subtract geometric line-of-sight distance from the middle The ranging deviation was obtained. The system maintains a first-in-first-out (FIFO) historical data buffer for each satellite, and the system stores tuples... Store in the buffer. The buffer length can be set to... Each epoch (e.g., the amount of data corresponding to the past 3 seconds) is used to support short-term trend analysis.

[0037] Before storing the ranging deviation of the current epoch into the historical data buffer, the system executes a cycle slip detection mechanism to ensure the continuity and trend validity of the data in the buffer.

[0038] Specifically, the system employs a conventional cycle slip detection method. It checks the satellite's Loss of Lock Indicator (LLI) in the differential data packet, or calculates whether the difference between the current ranging deviation and the ranging deviation of the previous epoch exceeds a preset wavelength threshold (e.g., half a carrier wavelength or a preset empirical jump threshold). If the LLI flag is detected as set or the difference exceeds the threshold, the system determines that a cycle slip has occurred in the satellite signal.

[0039] Because cycle slips cause instantaneous jumps in carrier phase observations (corresponding to meter-level or even kilometer-level steps in distance), if subsequent RANSAC algorithms attempt to fit the trend across this jump point, they will obtain incorrect slope parameters, leading to reconstruction failure. Therefore, once a cycle slip is detected, the system immediately clears the historical data buffer for the corresponding satellite, restarts data accumulation, and ceases using historical data from before the jump for trend extrapolation.

[0040] It should be noted that the approximate coordinates The absolute error mainly introduces a relatively stable constant term offset or an extremely low-frequency, slowly varying component into the calculated ranging bias. Since subsequent steps primarily focus on the high-frequency jitter characteristics of the ranging bias (for multipath detection) and the linear drift slope (for trend reconstruction), both of which are insensitive to the constant term offset. Furthermore, in the differential positioning double-difference algorithm of downstream RTK devices, this common constant term error is completely eliminated. Therefore, even if the SPP solution accuracy is limited, it will not affect the convergence and fixation of the final high-precision positioning.

[0041] It should be noted that the analysis process for each differential positioning data packet is the same. The system first parses the data packet to obtain the identifiers (PRN numbers) of all visible satellites contained in the current epoch and establishes a satellite index sequence. Subsequently, the system traverses this sequence and performs calculations and analyses for each satellite separately. The analysis process for each satellite is consistent, and only one example is described here without repeating the explanation.

[0042] Meanwhile, the system dynamically maintains the historical data buffer using satellite identifiers as keys. If the current data packet does not contain any satellite data (e.g., communication data is corrupted or completely blocked), or if a satellite is interrupted (lost) in the current epoch, the system will skip the processing of that epoch or clear the historical buffer of the corresponding satellite and stop outputting the reconstructed data of that satellite until new observation data containing that satellite is received.

[0043] Step S2: Based on the change in phase observation distance between adjacent epochs, compare the Doppler observation velocity and combine the difference between the satellite elevation angle and the maximum obstruction elevation angle to determine the Doppler availability status; calculate the extrapolation span based on the data generation time and the preset target time; for satellites where Doppler is unavailable, extract the deviation trend parameters from the historical ranging deviation sequence and update the downgrade flag.

[0044] In practical engineering, the carrier tracking loop (PLL) and frequency tracking loop (FLL) of a GNSS receiver have different loop bandwidths and dynamic response characteristics. When a strong multipath signal (non-line-of-sight signal or synthesized signal) enters the receiver, the phase observation (cumulative quantity) and the Doppler observation (instantaneous quantity) will produce asynchronous numerical responses to signal distortion under the filtering effect of different bandwidths, which is manifested as statistical inconsistency in the rate of change of the two. In addition to signal dimension analysis, a digital elevation model (DEM) is also introduced for auxiliary judgment, extracting the maximum obstruction elevation angle and identifying the potential obstruction risk of satellite signals by large-scale, long-term stable landforms such as the main body of the deep pit rock wall. Therefore, based on the changes in phase observation distance between adjacent epochs, the Doppler observation velocity is compared, and the difference between the satellite's elevation angle and the maximum obstruction elevation angle is considered to determine the Doppler availability status. By constructing a dual judgment mechanism of "microscopic signal response difference" and "macroscopic terrain risk", the Doppler velocity anomaly caused by deep pit multipath effect can be accurately identified. In the subsequent reconstruction process, the accumulation of velocity error and distance divergence caused by directly using Doppler data contaminated by multipath for time delay extrapolation is effectively avoided, ensuring the physical authenticity of the reconstructed data.

[0045] Preferably, in one embodiment of the present invention, in order to prevent receiving duplicate packets (with the same timestamp) due to network retransmission or division by zero anomalies due to extremely short sampling intervals, the current epoch time is compared before analyzing the change in phase observation distance between adjacent epochs. and the adjacent previous epoch Calculate the time difference ; like ( For example, the minimum time resolution of the system If the time interval is less than one millisecond, the system determines that the current epoch is invalid or a duplicate sample, and directly sets the time interval to zero. It equals the calculated value of the previous epoch, or skips the current detection step.

[0046] like Then, proceed with the following calculations: obtain the rate of change of the phase observation distance between the current epoch and the adjacent previous epoch, as the phase difference velocity. ; Then, based on the difference between the phase difference velocity and the Doppler observed velocity, the velocity deviation is obtained. As an example, The difference between data is represented by the absolute value of the difference; the velocity deviation characterizes the degree of inconsistency between the two observation channels in engineering measurements. In an ideal environment without multipath propagation, The value should be close to zero (affected only by measurement noise); however, in environments with severe multipath propagation, The value will increase significantly.

[0047] Then the system utilizes As an index, the first [item] is retrieved from the preset DEM. azimuth of satellite The terrain profile is shown. The maximum occlusion elevation angle of terrain obstacles in this direction is calculated using a ray tracing algorithm. (Publicly known technology). Based on the satellite's elevation angle The terrain occlusion factor is obtained from the difference between the elevation angle and the maximum occlusion angle. ; As an example, when When the satellite's line of sight is completely blocked by terrain obstacles or is in a diffraction blind zone extremely close to the Earth's surface, the directly received signal is mainly a non-line-of-sight reflected signal or a strongly attenuated signal, lacking the availability for high-precision positioning. Therefore, it is directly determined that the i-th satellite is currently in the obstruction area. Set to preset maximum value For example, 100, or the flag is unavailable; when hour, ,in, This represents the minimum value function, which uses a sine function to represent the difference between the satellite elevation angle and the maximum obstruction elevation angle. When the satellite line of sight gradually approaches or falls below the edge of the rock wall, the diffraction and multipath risks increase sharply in a nonlinear manner. At this time, the mapping value after the sine function decreases sharply, and the logical relationship is adjusted by using the power of -1 (taking the reciprocal). The larger the terrain obstruction factor, the greater the terrain obstruction factor.

[0048] The values ​​for both the satellite elevation angle and the maximum obstruction elevation angle are within the range of 0-90 degrees and then 0-π / 2 radians, and there are angular constraints before the calculation. The range of values ​​must be (0, ...). Within this interval, the sine function is monotonically increasing and has no periodicity, meaning that the terrain occlusion factor is unique. The larger the value, the closer the satellite is to or has been occluded by the terrain.

[0049] Finally, based on the velocity deviation and terrain occlusion factor, the Doppler availability status of each satellite is determined.

[0050] As an example, when the velocity deviation is greater than the preset velocity consistency threshold, or the terrain occlusion factor is greater than the preset terrain risk threshold, the satellite is determined to be Doppler unavailable; when the velocity deviation is less than or equal to the preset velocity consistency threshold, and the terrain occlusion factor is less than or equal to the preset terrain risk threshold, the satellite is determined to be Doppler available.

[0051] In this example, a preset speed consistency threshold is used to determine whether the signal's microscopic quality is acceptable. An empirical value can be set as follows: m / s, 0.10 in this example. The value is usually slightly larger than the receiver's nominal velocity noise level in open environments.

[0052] A preset terrain risk threshold is used to determine whether the satellite's geometric location is in a high-risk zone. An empirical value can be set as follows: In this example, we take 3.5.

[0053] The Doppler availability status is determined by the status of the internal control flag, which includes two states: "available" and "unavailable." The "available" state indicates that the current Doppler observation is not significantly affected by multipath interference and has high reliability; the "unavailable" state indicates that the current Doppler observation is contaminated or located in a high-risk terrain area and has no extrapolation value. This flag will serve as the direct basis for selecting the subsequent data reconstruction mode.

[0054] It should be noted that if a digital elevation model (DEM) is not deployed at the construction site, or if the DEM data is unavailable, the system will set the terrain occlusion factor to 0 by default and make Doppler availability determination only based on the velocity deviation.

[0055] It should be noted that for the first epoch when the system starts up, since there is no data from the previous epoch, the rate of change of the phase observation distance cannot be calculated. Therefore, the system defaults to the Doppler availability status of this epoch as "unavailable" (or directly executes the pass-through strategy), and executes the decision logic starting from the second epoch after initialization is completed.

[0056] The minimum time resolution of the system is determined by the hardware clock frequency or data sampling rate of the receiver board, and is usually set to a value slightly smaller than the minimum nominal sampling interval. The preset speed consistency threshold and preset terrain risk threshold can be offline statistically calibrated by collecting measured data at typical deep pit construction sites. Statistical quantiles that can distinguish between line-of-sight signals and multipath signals are selected as empirical values, and will not be elaborated further.

[0057] Due to the transmission delay in the satellite communication link, the differential data packets arriving at the gateway lag behind the real-time observation time required by the downstream RTK equipment. In order to compensate for this lag and achieve strict synchronization with the local sampling time, the system needs to calculate the extrapolation span based on the data generation time and the preset target time to provide a time reference for subsequent data extrapolation and reconstruction. Furthermore, since the instantaneous velocity information of satellites deemed unusable by Doppler is contaminated by multipath interference and cannot accurately reflect distance changes, directly using Doppler extrapolation would lead to error accumulation. Therefore, for satellites unusable by Doppler, the system extracts the deviation trend parameters from the historical ranging deviation sequence and updates the degradation flag. This aims to replace the high-frequency contaminated velocity with the low-frequency geometric and clock bias trends that are less affected by multipath interference, ensuring the continuity and availability of observation data even when there are no reliable velocity observations.

[0058] Preferably, in one embodiment of the present invention, the difference between the preset target time and the data generation time is used as the extrapolation span. ; The system extracts the satellite's most recent data from the historical data buffer. The system generates a series of ranging biases over each epoch (e.g., corresponding to the past 3 seconds). To simplify calculations and eliminate the accuracy loss caused by large values, the system converts the time axis to a timeline relative to the current moment. relative time .

[0059] Building the dataset: Where i corresponds to the i-th satellite, This represents the data generation time of the k-th epoch in the historical sequence; Indicates the relative time of the i-th satellite Distance measurement deviation.

[0060] When Doppler observations are unavailable due to multipath contamination, the system requires an alternative that does not rely on instantaneous velocity observations to predict changes in ranging bias in the future: a linear fit is made to historical ranging biases, where the slope captures and predicts deterministic trends in the biases, replacing contaminated Doppler velocities for time extrapolation; the intercept provides an accurate starting point for bias prediction, ensuring that the reconstructed observations are consistent with the real physical world in terms of numerical magnitude, so the bias trend parameters include the shift rate and intercept of the fitted linear line of the historical ranging bias sequence.

[0061] Since multipath effects often manifest as instantaneous jumps in observations or outliers, direct least-squares fitting is easily skewed by these outliers. Therefore, this system employs the Random Sample Consensus Algorithm (RANSAC) to fit the dataset. Robust linear regression is performed to extract the underlying physical fact that receiver clock drift and environmental error changes typically exhibit a linear trend over short time spans (e.g., seconds). The low-frequency linear trend caused by the deviation, where the slope mainly reflects the slow changes in receiver clock drift rate and atmospheric delay, while the intercept includes the variation caused by... The constant offset and other static deviations caused by absolute error.

[0062] It should be noted that, Each epoch must belong to the same continuous phase tracking arc. If a cycle slip event is detected in the buffer (lost lock flag set or wavelength-level step occurs), the system will only extract the latest data segment after the cycle slip occurrence as the dataset; Please see Figure 2The flowchart illustrates a method for obtaining a deviation trend parameter according to an embodiment of the present invention, specifically including: S201, Random Sampling: From the dataset Two sample points were randomly selected from the data. and .

[0063] S202, Model Building: Calculate the parameters of the straight line passing through these two points, i.e., the temporary slope. With temporary intercept .

[0064] S203, Interior Point Statistics: Traversing the Dataset For all sample points, calculate the residual distance from each point to the line. If the residual is less than a preset tolerance threshold (e.g., ...), then... If the distance is less than 1 meter, then the sample point is marked as an inlier.

[0065] S204, Iterative optimization: Repeat steps S201-S203 for a total of Next (for example) (This may involve traversing all sample point combinations once or after iterating through all sample point combinations). Record the parameter model with the largest number of interior points, and extract the corresponding slope, denoted as . The intercept is denoted as .

[0066] RANSAC is a classic robust regression algorithm, which will only be briefly described here. In actual operation, if multiple parameter models are found to achieve the same optimal number of inliers (the model with the most inliers has the highest number of parameters), the parameters of the first model found will be used as the final trend parameters. There may also be situations where insufficient historical data or excessive data dispersion prevents the extraction of a valid trend; in such cases, a downgrade flag will be set as a fallback. Before each degradation flag update, the degradation flag is reset to invalid. Within the historical range deviation sequence, points whose residual from the sample point to the fitted line is less than a preset tolerance threshold are marked as inliers. When the proportion of inliers to all sample points is less than a preset inlier proportion threshold, or the total number of sample points is less than a preset regression threshold, the downgrade flag is updated to be valid.

[0067] As an example, the preset inlier proportion threshold is 0.3 and the preset regression threshold is 3. When the proportion of inliers to all sample points is less than 0.3, it indicates that the historical data is extremely discrete and there is no significant linear pattern; or when the total number of sample points is less than the preset regression threshold, it indicates that the minimum regression requirement is not met (the calculation of the deviation trend parameter is skipped). In this case, the deviation trend parameter is invalid and the downgrade flag is valid.

[0068] It should be noted that the preset tolerance threshold, preset inlier ratio threshold, and preset regression threshold can be set according to the statistical characteristics of historical observation data or the results of on-site calibration under typical application scenarios. In other embodiments of the present invention, the implementer can adaptively adjust and optimize each threshold parameter according to the specific positioning accuracy requirements, the severity of the multipath environment on site, and the performance indicators of the receiver hardware used. When there are multiple sets of model parameters with the largest number of inliers, the average value of multiple model parameters can also be taken.

[0069] Step S3: Based on the deviation trend parameters, extrapolation span, approximate coordinates, and the status of the degradation flag, and according to the Doppler availability status of each satellite, a preset reconstruction mode is selected to obtain the reconstructed phase observation values, which are then encapsulated and transmitted.

[0070] The deviation trend parameter reflects the historical evolution of ranging deviation, the extrapolation span clarifies the length of time compensation, the approximate coordinates establish the spatial geometric benchmark, the state of the degradation flag characterizes the reliability of historical trend extraction, and the Doppler availability state of each satellite directly determines whether the current Doppler observation velocity is reliable. Therefore, based on the deviation trend parameter, extrapolation span, approximate coordinates, and the state of the degradation flag, a preset reconstruction mode is selected according to the Doppler availability state of each satellite to obtain reconstructed phase observation values. This enables adaptive strategy switching under different signal quality and data availability conditions, preserving high-frequency dynamic details when Doppler is reliable and achieving robust extrapolation using historical geometric trends when Doppler fails. This maximizes the accuracy and continuity of the output observation data, which is then encapsulated and transmitted.

[0071] Preferably, in one embodiment of the present invention, the preset reconstruction mode includes a velocity integral mode, a geometric trend synthesis mode, and a degradation mode.

[0072] The selection method for the preset reconstruction mode includes: when the satellite is determined to be Doppler available, it means that the satellite's Doppler observations are not significantly affected by multipath interference and can accurately reflect the rate of change of line-of-sight distance, so the velocity integration mode is selected; when the satellite is determined to be Doppler unavailable: if the degradation flag is in an invalid state, it means that the historical ranging deviation data is sufficient and the linear trend is significant, which can provide reliable low-frequency extrapolation parameters, so the geometric trend synthesis mode is selected; if the degradation flag is in an valid state, it means that the historical data is insufficient or the dispersion is too large, and it is impossible to extract effective deviation trend parameters, so the degradation mode is selected.

[0073] Furthermore, the reconstructed phase observations are calculated: When the velocity integration mode is selected, the current phase observation distance is linearly extrapolated using the Doppler observation velocity and the extrapolation span to obtain the initial reconstruction value. ; As an example, In the formula, i corresponds to the i-th satellite. The current phase observation distance, To extrapolate the span, This refers to the Doppler observation speed.

[0074] When the geometric trend synthesis mode is selected, the predicted coordinates and approximate coordinates of the satellite at the preset target time are compared to obtain the theoretical geometric line-of-sight distance. Using the deviation trend parameter and the extrapolation span, the theoretical geometric line-of-sight distance is linearly extrapolated to obtain the initial reconstruction value. As an example, satellites in The spatial position changes during this period are objective physical facts and can be accurately predicted. The system retrieves the Kepler orbital parameters and their variability from the satellite's ephemeris, and then... The orbital status of the satellite from Recursively push to the preset target time The updated predicted coordinates of the satellites are obtained. ; calculate Approximate coordinates of the machine The Euclidean distance between them is used as the theoretical geometric line-of-sight distance at the preset target time. ; ; In the formula, The slope of the deviation trend parameter obtained in step S2. This is the intercept.

[0075] When the degradation mode is selected, the phase observation distance is used as the initial reconstruction value for the preset target time; Finally, when switching between different reconstruction modes, the initial reconstruction values ​​calculated based on different physical principles or data sources will have a fixed numerical deviation. This deviation will cause discontinuous jumps in the final output phase observation sequence at the switching point. Downstream RTK solvers will misjudge such jumps as integer cycle jumps in the carrier phase or signal loss, thereby triggering the re-initialization process of integer ambiguity, which seriously damages the continuity and convergence of positioning. Therefore, a phase alignment deviation correction mechanism needs to be introduced: based on the switching of the preset reconstruction mode, the deviation value in the register is updated, the initial reconstruction value and the deviation value are fused, and the reconstructed phase observation value is obtained.

[0076] When the system detects that the reconstruction mode of the current epoch is inconsistent with that of the adjacent previous epoch, a new alignment deviation is calculated. , =The output value sent by the system to the downstream RTK device in the previous epoch - the current initial reconstruction value; update the calculated new alignment offset to the alignment offset register, and Superimposed on the current initial reconstruction value This is the final output, ensuring the numerical continuity of the phase data stream at the moment of mode switching.

[0077] Alignment deviation The core objective is to introduce a compensation value at the moment of mode switching to offset the systematic deviation between different modes, thereby ensuring that the sequence of reconstructed phase observations output to the RTK device is numerically smooth and continuous, technically eliminating misjudgments caused by mode switching and ensuring the realization of high-reliability positioning; when the reconstructed modes of adjacent epochs are the same, the alignment deviation remains unchanged.

[0078] It should be noted that this method is mainly applicable to scenarios where communication is interrupted or packet jitter lasts for a short period of time (e.g., less than 10 seconds). If the continuous reconstruction time exceeds a preset threshold (e.g., 10 seconds), the system will forcibly clear the historical buffer and reset the alignment deviation, waiting for the receiver to relock the true observation value to prevent the accumulated error from spreading indefinitely.

[0079] When the preset reconstruction mode is set to degrade mode, the satellite's signal quality indicator is marked as "low precision" in the data packet, informing downstream equipment to reduce the satellite's weight.

[0080] Finally, after completing the reconstruction calculations, the system will Divide by carrier wavelength The system then reverse-engineers the carrier phase cycles. For satellites using the geometric trend synthesis mode, the system sets the corresponding Doppler observation field to zero or marks it as invalid to prevent downstream equipment from misusing contaminated velocity information.

[0081] The system reassembles the differential data frames according to the RTCM 3.x protocol standard. The system updates the GPS reference timestamp in the frame header to align with the target time. The system then recalculates the Cyclic Redundancy Check (CRC) code. Finally, the system sends the reconstructed standard data stream to the positioning and calculation board of the construction machinery in real time via the gateway's serial port or network interface. The downstream equipment will receive a set of highly reliable observation data with strictly aligned timestamps and free from multipath velocity outliers.

[0082] An embodiment of the present invention also provides a satellite internet high-reliability positioning and communication system during construction. The system includes a memory, a processor, and a computer program. The memory is used to store the corresponding computer program, and the processor is used to run the corresponding computer program. When the computer program runs in the processor, it can implement the satellite internet high-reliability positioning and communication method described in steps S1-S3 during construction.

[0083] In summary, to address the technical problem of obtaining accurate reconstructed phase observations due to the coupling of satellite communication link delay jitter and on-site multipath effects in complex construction environments, this invention provides a highly reliable satellite internet positioning communication method and system for construction processes. This invention first acquires differential positioning data packets, calculates the approximate coordinates and geometric line-of-sight distance of the construction machinery, and then compares the phase observation distance with the geometric line-of-sight distance to obtain the ranging deviation. Further, based on the change in phase observation distance between adjacent epochs, it compares the Doppler observation velocity and, combined with the difference between the satellite's elevation angle and the maximum obstruction elevation angle, determines the Doppler availability status. For satellites with unavailable Doppler, it extracts the deviation trend parameter of the ranging deviation and updates the degradation flag. Finally, based on the Doppler availability status of each satellite, it selects a preset reconstruction mode, obtains the reconstructed phase observations, and encapsulates and transmits them. This invention extracts ranging deviations by calculating approximate coordinates, combines phase change rate, Doppler observations, and obstruction elevation angles to determine Doppler availability, and generates highly reliable phase observations under the coupling of multipath and satellite link delays, ensuring the stability and accuracy of satellite positioning communication in complex construction environments.

[0084] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0085] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A highly reliable satellite internet positioning and communication method during construction, characterized in that, The method includes: Acquire differential positioning data packets transmitted via low-Earth orbit satellite links. For each current satellite: calculate the approximate coordinates of the construction machinery based on pseudorange observations and satellite ephemeris, and calculate the geometric line-of-sight distance; compare the phase observation distance with the geometric line-of-sight distance to obtain the ranging deviation. Based on the changes in the phase observation distance between adjacent epochs, the Doppler observation velocity is compared, and the difference between the satellite's elevation angle and the maximum obstruction elevation angle is considered to determine the Doppler availability status. The extrapolation span is calculated based on the data generation time and the preset target time. For satellites where Doppler is unavailable, the deviation trend parameters are extracted from the historical ranging deviation sequence and the degradation flag is updated. Based on the deviation trend parameters, the extrapolation span, the approximate coordinates, and the status of the degradation flag, a preset reconstruction mode is selected according to the Doppler availability status of each satellite to obtain the reconstructed phase observation values, which are then encapsulated and transmitted. The preset reconstruction modes include velocity integral mode, geometric trend synthesis mode, and degradation mode; The method for obtaining the reconstructed phase observation values ​​includes: for each satellite currently: when the velocity integration mode is selected, the current phase observation distance is linearly extrapolated using the Doppler observation velocity and the extrapolation span to obtain an initial reconstruction value; when the geometric trend synthesis mode is selected, the predicted coordinates of the satellite at a preset target time are compared with the approximate coordinates to obtain the theoretical geometric line-of-sight distance, and the theoretical geometric line-of-sight distance is linearly extrapolated using the deviation trend parameter and the extrapolation span to obtain an initial reconstruction value; when the degradation mode is selected, the phase observation distance is used as the initial reconstruction value at the preset target time; according to the switching of the preset reconstruction mode, the deviation value in the register is updated, and the initial reconstruction value and the deviation value are fused to obtain the reconstructed phase observation value.

2. The satellite internet high-reliability positioning and communication method during construction as described in claim 1, characterized in that, The method for selecting the preset reconstruction mode includes: When the satellite is determined to be Doppler available, the velocity integration mode is selected; when the satellite is determined to be Doppler unavailable: if the degradation flag is invalid, the geometric trend synthesis mode is selected; if the degradation flag is valid, the degradation mode is selected.

3. The satellite internet high-reliability positioning and communication method during construction as described in claim 1, characterized in that, The method for determining the usability of Doppler includes: For each satellite currently in use: obtain the rate of change of the phase observation distance between the current epoch and the adjacent previous epoch, as the phase difference velocity; obtain the velocity deviation based on the difference between the phase difference velocity and the Doppler observation velocity; obtain the terrain occlusion factor based on the difference between the satellite's elevation angle and the maximum occlusion elevation angle. Based on the velocity deviation and the terrain occlusion factor, the Doppler availability status of each satellite is determined.

4. The satellite internet high-reliability positioning and communication method during construction as described in claim 3, characterized in that, The method for determining the current Doppler availability status of each satellite based on the velocity deviation and the terrain occlusion factor includes: When the velocity deviation is greater than a preset velocity consistency threshold, or the terrain occlusion factor is greater than a preset terrain risk threshold, the satellite is determined to be Doppler unavailable; when the velocity deviation is less than or equal to the preset velocity consistency threshold, and the terrain occlusion factor is less than or equal to the preset terrain risk threshold, the satellite is determined to be Doppler available.

5. A high-reliability satellite internet positioning and communication method during construction as described in claim 1, characterized in that, The deviation trend parameters include the shift rate and intercept of the fitted straight line of the historical sequence of the ranging deviation.

6. A high-reliability satellite internet positioning and communication method during construction as described in claim 5, characterized in that, The fitted straight line is obtained using a random sampling consensus algorithm.

7. A high-reliability satellite internet positioning and communication method during construction as described in claim 5, characterized in that, The method for updating the degradation flag includes: Within the historical sequence of ranging biases, points where the residual from the sample point to the fitted straight line is less than a preset tolerance threshold are marked as inliers. When the proportion of inliers to all sample points is less than a preset inlier proportion threshold, or the total number of sample points is less than a preset regression threshold, the degradation flag is updated to be valid.

8. A high-reliability satellite internet positioning and communication system during construction, the system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the satellite internet high-reliability positioning and communication method during construction as described in any one of claims 1 to 7.

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