Floating platform tide gauge method based on offshore GNSS data

Abstract

The invention relates to the technical field of sight distance measurement, and discloses a floating platform tide gauge method based on offshore GNSS (Global Navigation Satellite System) data, comprising GNSS equipment and communication equipment, and comprising the following steps: S01, deploying at least one piece of GNSS equipment sufficient to cover a detection area, and transmitting the GNSS equipment through the communication equipment to establish connection with a user side; s02, the data center of the user side receives real-time GNSS data transmitted by the GNSS device and stores the real-time GNSS data to obtain a GNSS data set; and S03, performing abnormal point deletion and data filtering correction on the received GNSS data set to obtain tide gauge data of the offshore point location. According to the method, accurate tide gauge data are obtained through correction such as GNSS elevation data abnormal point deletion and data filtering, and the problem that the precision of tide gauge data is too low due to displacement of a sinking type tide level instrument in areas such as a shore-based tide gauge station or a strong tide estuary and a soft substrate cannot be arranged in a long-distance offshore operation area is solved.

Description

Technical Field

[0001] The invention relates to line-of-sight measurement, and in particular to a floating platform tide measurement method based on offshore GNSS data. Background Art

[0002] The so-called tide gauge is the observation of water level. Through the observation of water level, we can intuitively understand the local tidal characteristics. Through the data obtained by observation, we can calculate the tidal harmonic parameters, mean sea level, depth reference surface, tide forecast of the area and provide water level correction numbers for measuring different times.

[0003] There are two types of tide measurement methods in the prior art: shore-based and offshore.

[0004] Shore-based type, which is divided into water gauge tide gauge, float tide gauge tide gauge, pressure water level gauge and radar water level gauge tide gauge. It is mainly through the construction of corresponding observation stations. In strong tidal estuaries or silted coastal areas, not only the investment is huge, but also the site selection is difficult. The siltation of the station will also seriously affect the precision and accuracy of the observation;

[0005] Compared with the shortcomings of the shore-based type, the offshore type is more flexible, but after deployment, it will be affected by water flow and deadweight and will have a vertical deviation. This change is generally difficult to measure and has a great impact on data accuracy.

[0006] Therefore, there is a need for a method that has the flexibility of an offshore tide gauge method while avoiding the problem of being greatly disturbed by external interference in a shore-based tide gauge method, and we look forward to a good solution. Summary of the invention

[0007] The purpose of the present invention is to provide a floating platform tide measurement method based on offshore GNSS data to solve the above problems.

[0008] In order to achieve the above object, the present invention provides the following technical solution: a floating platform tide measurement method based on offshore GNSS data, including GNSS equipment and communication equipment, including the following steps:

[0009] S01, deploying at least one GNSS device sufficient to cover the detection area, and communicating the GNSS device with the user end through the communication device;

[0010] S02. The data center of the user terminal receives and stores the real-time GNSS data transmitted by the GNSS device to obtain a GNSS data set;

[0011] S03, deleting abnormal points and correcting data filtering on the received GNSS data set to obtain tide measurement data of offshore points;

[0012] S04. The user terminal feeds back the tidal height data of the offshore point to the user.

[0013] Preferably, the GNSS data includes time and three directions of east, north and altitude.

[0014] Preferably, the observation frequency of the GNSS device is 10 Hz.

[0015] Preferably, the step S03 of deleting abnormal points and correcting data filtering of the received GNSS data set includes:

[0016] S31, based on a GNSS data set fed back by the GNSS device, 秒平均 , H 分钟平均 and H 小时平均 , construct outlier screening from top to bottom through hourly average, delete the points exceeding the threshold as outliers, obtain the outlier data set and the normal data set, and then fit them through polynomials to obtain the fitting curve;

[0017] S32, after smoothing the obtained fitting curve, interpolation processing is performed, and then polynomial interpolation is used to solve the tidal height of the point.

[0018] Preferably, the step S31 includes:

[0019] S311, sequentially calculating the average values ​​of the height of the GNSS data set for 1 second, 1 minute, and 60 minutes, wherein:

[0020] The calculation method for the 1-second average value is:

[0021]

[0022] Wherein, H is the highest data in the GNSS data, i is 10 GNSS data obtained by deploying at least one GNSS device sufficient to cover the detection area and performing 10 Hz observation within 1 second;

[0023] The 1-minute average is calculated as:

[0024]

[0025] Among them, H 分钟平均 For H within 60 seconds 秒平均 Find the average value obtained;

[0026] The calculation method for the 1-hour average is:

[0027]

[0028] Among them, H小时平均 For 60 minutes of H 分钟平均 Find the average value obtained;

[0029] S312, the obtained multiple H 小时平均 , and get L by fitting it with a polynomial 小时 Fit the curve and record the data of the fitting curve as H 小时拟合 , calculate the difference between the data before and after fitting:

[0030]

[0031] Double σ 小时 The size of H is used as the threshold to detect H values ​​that are beyond the ±2σ range of the fitting curve. 分钟平均 The data of is regarded as gross error and removed from the GNSS data set. The gross error removed is H 分钟平均 H 分钟剔除 ;

[0032] S313, fit it again through the polynomial to obtain L 分钟 Fit the curve and record the data of the fitting curve as H 分钟拟合 , calculate the difference between the data before and after fitting:

[0033]

[0034] Double σ 分钟 The size of is used as the threshold, and the data of H observation i that exceeds the range of ±2σ of the fitting curve is regarded as a gross error and is removed from the GNSS data set. The H observation i with gross errors removed is recorded as H second removal.

[0035] Preferably, the step S32 includes:

[0036] S321, using a moving average method to smooth the GNSS data set after deleting abnormal points,

[0037]

[0038] S322, calculating the GNSS data set with outliers deleted by an interpolation method,

[0039]

[0040] S322, calculate H 平滑i and H 插补i The GNSS data is then imported into (1) to obtain the tide height data.

[0041] In the above technical solution, the present invention provides a floating platform tide measurement method based on offshore GNSS data, which has the following beneficial effects:

[0042] 1. Data is collected directly using the floating platform, and the site layout is relatively convenient, and actual measurements can be made without the need to establish a station. At the same time, high-frequency GNSS observation combined with data processing avoids the problem of traditional bottom-mounted tide gauges being unable to obtain accurate tide data due to settlement or other displacements;

[0043] 2. By processing high-frequency GNSS observation data, the mean is calculated from seconds to minutes to hours, and then the abnormal points are screened and interpolated by constructing fitting curves for hours and minutes. The tide data is calculated using a simple and easy-to-implement algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0045] Figure 1 A flowchart provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] like Figure 1 As shown, a floating platform tide measurement method based on offshore GNSS data includes the following steps:

[0048] S01. Deploy at least one GNSS device that is sufficient to cover the detection area, and establish a connection between the GNSS device and the user end through a communication device;

[0049] S02. The data center at the user end receives and stores the real-time GNSS data transmitted by the GNSS device to obtain a GNSS data set;

[0050] S03, deleting abnormal points and correcting data filtering on the received GNSS data set to obtain tide gauge data of offshore points;

[0051] S04. The user end feeds back the tidal height data of the offshore point to the user.

[0052] Specifically, the deployment of at least one GNSS device sufficient to cover the detection area in the above embodiment means building a floating platform according to the detection area in advance, fixing the floating platform through an anchor rod system, and then fixing the GNSS device, power supply equipment and communication equipment on the floating platform.

[0053] The observation frequency of GNSS equipment is 10Hz.

[0054] Furthermore, the GNSS data in the above embodiment includes time and three directions: east, north, and altitude. In step S03, the received GNSS data set is subjected to outlier deletion and data filtering correction, mainly for the altitude in the GNSS data. The detailed processing steps include:

[0055] Based on the GNSS dataset fed back by a GNSS device, the H 秒平均 , H 分钟平均 and H 小时平均 , construct outlier screening from top to bottom through hourly average, delete the points exceeding the threshold as outliers, obtain the outlier data set and the normal data set, and then fit them through polynomials to obtain the fitting curve, that is:

[0056] S311, sequentially calculating the average values ​​of the height of the GNSS data set for 1 second, 1 minute, and 60 minutes, wherein:

[0057] The calculation method for the 1-second average value is:

[0058]

[0059] Wherein, H is the highest data in the GNSS data, i is 10 GNSS data obtained by deploying at least one GNSS device sufficient to cover the detection area and performing 10 Hz observation within 1 second;

[0060] The 1-minute average is calculated as:

[0061]

[0062] Among them, H 分钟平均 For H within 60 seconds 秒平均 Find the average value obtained;

[0063] The calculation method for the 1-hour average is:

[0064]

[0065] Among them, H 小时平均 For 60 minutes of H 分钟平均 Find the average value obtained;

[0066] S312, the obtained multiple H 小时平均 , and get L by fitting it with a polynomial 小时 Fit the curve and record the data of the fitting curve as H 小时拟合 , calculate the difference between the data before and after fitting:

[0067]

[0068] Double σ 小时 The size of H is used as the threshold to detect H values ​​that are beyond the ±2σ range of the fitting curve. 分钟平均 The data is treated as gross errors and removed from the GNSS data set. The data after removing the gross errors is recorded as H 分钟平均 H 分钟剔除 ;

[0069] S313, fit it again through the polynomial to obtain L 分钟 Fit the curve and record the data of the fitting curve as H 分钟拟合 , calculate the difference between the data before and after fitting:

[0070]

[0071] Double σ 分钟 The size of is used as the threshold, and the data of H observation i that exceeds the range of ±2σ of the fitting curve is regarded as a gross error and is removed from the GNSS data set. The H observation i with gross errors removed is recorded as H second removal.

[0072] The purpose of smoothing the obtained fitting curve is that since the GNSS platform is directly deployed on the water surface, it is not only affected by the tide level, but also by various factors such as currents, ship waves and wind. Abnormal values ​​may occasionally appear in the observation. These influences are short-period data relative to the tidal level changes, and the tidal level changes are long-period changes. Therefore, using high-frequency observations to obtain the average values ​​of seconds, minutes and hours respectively can smooth the data and eliminate the influence of short-period data on the abnormal data of tidal observations.

[0073] The purpose of interpolation after smoothing is that the change of tide level is a continuous process without mutation. Therefore, if there is enough observation data, some missing data can be interpolated. When the data observation density is high enough, it can even be considered that the data within a short period (such as 1 minute) is linearly related. In order to better fit the tide level observation.

[0074] Finally, polynomial interpolation is used to solve the tidal height of the point.

[0075] The detailed steps of the above embodiment are as follows:

[0076] S321, using a moving average method to smooth the GNSS data set after deleting abnormal points,

[0077]

[0078] S322, calculating the GNSS data set with outliers deleted by an interpolation method,

[0079]

[0080] S322, calculate H 平滑i and H 插补i The GNSS data is then imported into (1) to obtain the tide height data.

[0081] It should be noted that the polynomial in the above embodiment is fitted by determining the order of the fitting polynomial. Since the amount of collected data is large, the known 6 data closest to the point to be interpolated are used (here there are three cases, there are three data before and after the point to be inserted, and the data before or after the point to be inserted is more than 3, which does not affect the operation of the algorithm). A total of 6 points are interpolated by the cubic spline method, and the process is as follows:

[0082] 1) Read known data, that is, node (x i ,y i ), i ranges from 0 to 5, and the point to be inserted is marked as (x′, y′)

[0083] 2) For i = 0, 1, ..., 5, calculate h i =x i+1 -x i

[0084] 3) Calculate α i and β i (i=0,1,…,5)

[0085]

[0086] For i=1,…,4 calculate:

[0087]

[0088] 4) Calculate a i and b i (i=0,1,…,5)

[0089]

[0090] For i=1,…,5 calculate:

[0091]

[0092] 5) Calculate m i (i=0,1,…,5)

[0093] m n =b n

[0094] m i =a i m i+1 +b i (i=n-1,...,1,0)

[0095] 6) Determine the interval [x i , x i+1 ](i=0,1,...,5), then find the corresponding value and output it:

[0096]

[0097] In the above, x represents the observation time, y represents the tide height at the observation time; h is the step size, and a, b, α, β, and m are the correlation coefficients of cubic spline interpolation.

[0098] In the above technologies, data is collected directly using a floating platform, and its site layout is relatively convenient, and actual measurements can be made without building a station. At the same time, high-frequency GNSS observation combined with data processing avoids the problem of traditional bottom-mounted tide gauges being unable to obtain accurate tide data due to settlement or other displacements.

[0099] By processing high-frequency GNSS observation data, the mean was calculated from seconds to minutes to hours, and then the outliers were screened and interpolated by constructing fitting curves for hours and minutes. The tide data was calculated using a simple and easy-to-implement algorithm.

[0100] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0101] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0102] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0103] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0104] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0105] The embodiments of the present application also provide a specific implementation of an electronic device capable of implementing all steps of the method in the above embodiments, and the electronic device specifically includes the following contents:

[0106] Processor, memory, communications interface and bus;

[0107] Wherein, the processor, memory, and communication interface communicate with each other via the bus;

[0108] The processor is used to call the computer program in the memory, and when the processor executes the computer program, all the steps in the method in the above embodiment are implemented.

[0109] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps of the method in the above embodiments, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, all the steps of the method in the above embodiments are implemented.

[0110] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the hardware + program embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. Although the embodiment of this specification provides the method operation steps described in the embodiment or flow chart, more or less operation steps can be included based on conventional or non-creative means. The order of steps listed in the embodiment is only one way of executing the order of many steps, and does not represent the only execution order. When the device or terminal product in practice is executed, it can be executed in sequence or in parallel according to the method shown in the embodiment or the accompanying drawings (for example, a parallel processor or a multi-threaded processing environment, or even a distributed data processing environment). The term "include", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, product or device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such a process, method, product or device. In the absence of more restrictions, it is not excluded that there are other identical or equivalent elements in the process, method, product or device including the elements. For the convenience of description, the above device is described by dividing it into various modules according to its functions. Of course, when implementing the embodiments of this specification, the functions of each module can be implemented in the same one or more software and / or hardware, or the module implementing the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the coupling or direct coupling or communication connection between each other shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms. The present invention is described with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the process and / or box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the process Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0111] Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems or computer program products. Therefore, the embodiments of this specification may be in the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the embodiments of this specification may be in the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts refer to the partial description of the method embodiment. In the description of this specification, the description of the reference term "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification.

[0112] In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradicting each other. The above is only an embodiment of the embodiment of this specification and is not intended to limit the embodiment of this specification. For those skilled in the art, the embodiment of this specification may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiment of this specification shall be included in the scope of the claims of the embodiment of this specification.

Claims

1. A floating platform tide measurement method based on offshore GNSS data, comprising GNSS equipment and communication equipment, characterized in that: The following steps are involved: S01, deploying at least one GNSS device sufficient to cover the detection area, and communicating the GNSS device with the user end through the communication device; S02. The data center of the user terminal receives and stores the real-time GNSS data transmitted by the GNSS device to obtain a GNSS data set; S03, deleting abnormal points and correcting data filtering on the received GNSS data set to obtain tide measurement data of offshore points; S04. The user terminal feeds back the tidal height data of the offshore point to the user.

2. A floating platform tide measurement method based on offshore GNSS data according to claim 1, characterized in that: The GNSS data includes time and three directions: east, north and altitude.

3. The floating platform tide measurement method based on offshore GNSS data according to claim 1 is characterized in that: The observation frequency of the GNSS device is 10 Hz.

4. The floating platform tide measurement method based on offshore GNSS data according to claim 1 is characterized in that: The step S03 includes deleting abnormal points and correcting data filtering of the received GNSS data set, including: S31, based on a GNSS data set fed back by the GNSS device, 秒平均 , H 分钟平均 and H 小时平均 , construct outlier screening from top to bottom through hourly average, delete the points exceeding the threshold as outliers, obtain the outlier data set and the normal data set, and then fit them through polynomials to obtain the fitting curve; S32, after smoothing the obtained fitting curve, interpolation processing is performed, and then polynomial interpolation is used to solve the tidal height of the point.

5. A floating platform tide measurement method based on offshore GNSS data according to claim 4, characterized in that: The step S31 includes: S311, sequentially calculating the average values ​​of the height of the GNSS data set for 1 second, 1 minute, and 60 minutes, wherein: The calculation method for the 1-second average value is: （1）； Wherein, H is the highest data in the GNSS data, i is 10 GNSS data obtained by deploying at least one GNSS device sufficient to cover the detection area and performing 10 Hz observation within 1 second; The 1-minute average is calculated as: （2）； Among them, H 分钟平均 For H within 60 seconds 秒平均 Find the average value obtained; The calculation method for the 1-hour average is: （3）； Among them, H 小时平均 For 60 minutes of H 分钟平均 Find the average value obtained; S312, the obtained multiple H 小时平均 , and get L by fitting it with a polynomial 小时 Fit the curve and record the data of the fitting curve as H 小时拟合 , calculate the difference between the data before and after fitting: （4）； Will double The size of Range of H 分钟平均 The data is treated as gross errors and removed from the GNSS data set. The data after removing the gross errors is recorded as H 分钟平均 H 分钟剔除 ; S313, fit it again through the polynomial to obtain L 分钟 Fit the curve and record the data of the fitting curve as H 分钟拟合 , calculate the difference between the data before and after fitting: （5）； Will double The size of The data of H observations i within the range are treated as gross errors and removed from the GNSS data set. The H observations i with gross errors removed are denoted as H second removals.

6. The method for tide measurement of a floating platform based on offshore GNSS data according to claim 4, characterized in that: The step S32 includes: S321, using a moving average method to smooth the GNSS data set after deleting abnormal points, （6）； S322, calculating the GNSS data set with outliers deleted by an interpolation method, （7）； S323, calculate H 平滑i and H 插补i The GNSS data is then imported into (1) to obtain the tide height data.

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