GNSS vibration-measurement system

Abstract

A GNSS vibration-measurement system, according to an embodiment of the present disclosure, comprises a GNSS receiver, a reference station that provides observation values from GNSS satellites, and a vibration-measurement processor unit that communicates with the GNSS receiver and the reference station through a network, wherein the vibration-measurement processor unit may comprise: an interface unit that communicates with the reference station and the GNSS receiver; a GNSS data-processing unit that processes the observation values received from the GNSS receiver and the reference station, removes errors, and formulates linear observation equations to produce time-series data; and a vibration-estimation unit that estimates vibration information through spectral analysis of the time-series data generated by the GNSS data-processing unit.

Description

GNSS Vibration Measurement System

[0001] The disclosed content relates to a GNSS vibration measurement system including a GNSS receiver.

[0002] Unless otherwise indicated in this specification, the contents described in this section are not prior art for the claims of this application, and are not to be recognized as prior art simply because they are included in this section.

[0003] GNSS (Global Navigation Satellite System) is a satellite-based position tracking and time synchronization system that provides accurate location, speed, and time information anywhere in the world. This system transmits radio signals through multiple satellites, and ground receivers analyze these signals to calculate the location. GNSS consists of various satellite systems operated by different countries and organizations. Representative systems include the U.S. Global Positioning System (GPS), Russia's GLONASS, Europe's Galileo, and China's BeiDou.

[0004] GNSS uses the principle of trilateration based on satellite signals. A receiver measures the arrival times of signals from multiple satellites to calculate the distance to each satellite, and based on this, determines the location on Earth in three dimensions. Through this, users can obtain geographical coordinates, altitude, and velocity information.

[0005] The accuracy of GNSS can be affected by various error factors (ionospheric and tropospheric delay, satellite clock errors, multipath, etc.). To improve this, correction techniques such as RTK (Real-Time Kinematic) or PPP (Precise Point Positioning) are used.

[0006] The disclosed content aims to provide a GNSS vibration measurement system capable of detecting vibration through spectrum analysis based on carrier signals of GNSS satellites received by a GNSS receiver.

[0007] A GNSS vibration measurement system according to an embodiment of the present disclosure comprises: a GNSS receiver; a reference station providing observation values ​​of a GNSS satellite; and a vibration measurement processor unit communicating with the GNSS receiver and the reference station through a network. The vibration measurement processor unit may include: an interface unit communicating with the reference station and the GNSS receiver; a GNSS data processing unit generating a linear observation equation and generating time series data by processing observation values ​​received from the GNSS receiver and the reference station to remove errors; and a vibration estimation unit estimating vibration information through spectrum analysis of the time series data generated from the GNSS data processing unit.

[0008] As an example, the linear observation equation can be calculated by the following formula.

[0009] (formula)

[0010]

[0011] Here, y is the residual observation vector with GNSS error removed,

[0012] is the transformation matrix,

[0013] x is the location of the GNSS receiver,

[0014] λ is the wavelength of the GNSS carrier,

[0015] N is an initial unknown integer,

[0016] e is the residual error vector

[0017] Q is the variance-covariance matrix representing the statistical characteristics of the residual error.

[0018]

[0019] As an example, the time series data is observation area time series data and can be calculated by the following formula.

[0020] (formula)

[0021]

[0022] Here, the subscript i is a subscript representing a specific GNSS satellite,

[0023] y is the residual observation vector with GNSS error removed,

[0024] λ is the wavelength of the GNSS carrier,

[0025] is the estimated value of the initial unknown vector,

[0026] is the transpose of the transformation matrix A, which is the vector for the corresponding satellite,

[0027] is the estimated position of the GNSS receiver,

[0028] e” is the change in a physical quantity (i.e., the signal transmission distance between the GNSS satellite and the GNSS receiver) that appears in the observation direction of the GNSS satellite due to oscillation, along with the residual error (e).

[0029]

[0030] As an example, the time series data is position value area time series data and can be calculated by the following formula.

[0031] (formula)

[0032]

[0033] Here, is the GNSS receiver's position estimate,

[0034] is the transformation matrix,

[0035] Is The transpose of,

[0036] y is the residual observation vector with GNSS error removed,

[0037] λ is the wavelength of the GNSS carrier,

[0038] is the estimated value of the initial unknown vector

[0039] is the inverse of Q

[0040]

[0041] As an example, the spectrum analysis may be characterized as a Lomb-Scargle Periodogram.

[0042] A GNSS vibration measurement system according to an embodiment of the present disclosure can eliminate errors in observation values ​​from GNSS satellites and measure the amplitude, period, and direction of vibrations on the 1st to 3rd axes through spectrum analysis.

[0043] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims.

[0044] FIG. 1 is a configuration diagram of a GNSS vibration measurement system according to an embodiment of the present disclosure.

[0045] FIG. 2 is a configuration diagram of a vibration measurement processor unit of a GNSS vibration measurement system according to an embodiment of the present disclosure.

[0046] FIG. 3 is an example of a parameter setting window for a vibration parameter control unit of a GNSS vibration measurement system according to an embodiment of the present disclosure.

[0047] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols will be assigned the same reference number, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not inherently possess distinct meanings or roles. Furthermore, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0048] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0049] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0050]

[0051] Hereinafter, a GNSS vibration measurement system according to an embodiment of the present disclosure will be described in detail with reference to the attached drawings.

[0052] FIG. 1 is a configuration diagram of a GNSS vibration measurement system according to an embodiment of the present disclosure, and FIG. 2 is a configuration diagram of a vibration measurement processor unit (300) of a GNSS vibration measurement system according to an embodiment of the present disclosure. Referring to FIG. 1, the GNSS vibration measurement system of the present disclosure may include a GNSS receiver (100), a reference station (200), and a vibration measurement processor unit (300).

[0053] The GNSS receiver (100) functions to receive a carrier signal from a GNSS satellite (10). That is, the GNSS receiver (100) may be an antenna that receives a type of satellite signal. The GNSS receiver (100) may be configured to receive various frequency bands so as to receive carrier frequencies from satellites such as the US GPS (Global Positioning System), Russia's GLONASS, Europe's Galileo, and China's BeiDou. The GNSS receiver (100) may include means for amplifying the signal of the GNSS satellite (10) to improve the signal-to-noise ratio of the signal of the GNSS satellite (10), and means for filtering to remove unnecessary frequency bands.

[0054] The GNSS receiver (100) can generate an observation value by receiving a carrier signal from a GNSS satellite (10) and compress it into a data format for transmission to a vibration measurement processor unit (300) to be described later. Generally, the data format may be RTCM (Radio Technical Commission for Maritime Services) Version 3 and RTCM MSM (Multiple Signal Message), which are used as industry standards. The GNSS receiver (100) is installed at a point to measure vibration.

[0055] The reference station (200) is a GNSS receiving facility fixedly installed on the surface of the Earth to increase the accuracy of the GNSS system and provide correction data. The reference station (200) can receive signals from the GNSS satellite (10) at a known accurate location and provide the observation values ​​of the GNSS satellite (10) to the vibration measurement processor unit (300), which will be described later, via the network (20). The reference station (200) can provide correction data to the vibration measurement processor unit (300) to calculate an error based on the observation values ​​of the GNSS satellite (10) of the reference station (200).

[0056] The vibration measurement processor unit (300) may be a computing device or process board comprising at least one CPU (Central Process Unit) and at least one memory device. The vibration measurement processor unit (300) may communicate with the GNSS receiver (100) and the reference station (200) via a network (20). Here, the network (20) may be a mobile communication network including 2G, 3G, 4G, 5G, and future 6G services, or a TCP / IP-based wired data network, but is not limited thereto. Referring to FIG. 2, the vibration measurement processor unit (300) may include an interface unit (310), a GNSS data processing unit (320), and a vibration estimation unit (330).

[0057] The interface unit (310) may include a communication module capable of communicating with the GNSS receiver (100) and the reference station (200). The communication module may support the aforementioned network (20). In other words, if the network (20) is a mobile communication network, the communication module may be a mobile communication module, and if the network (20) is a wired data network, the communication module may be an Ethernet communication module. The interface unit (310) functions to receive observation values ​​for the GNSS satellite (10) from the GNSS receiver (100) and the reference station (200).

[0058] The GNSS data processing unit (320) can process observation values ​​of the GNSS satellite (10) received from the GNSS receiver (100) and the reference station (200), remove errors, generate a linear observation equation, and generate time series data.

[0059] The carrier signal of the GNSS satellite (10) received from the GNSS receiver (100) may contain errors due to various factors. Factors of error may include tropospheric error due to delay of the signal of the GNSS satellite (10) caused by the refraction effect of the troposphere, ionospheric error due to refraction and delay of the signal of the GNSS satellite (10) caused by the electron density of the ionosphere, satellite orbit error caused by inaccurate orbit information of the GNSS satellite (10), multipath error caused by the signal of the GNSS satellite (10) reaching the GNSS receiver (100) after being reflected by surrounding objects, and receiver noise error caused by noise of the GNSS receiver (100). The GNSS data processing unit (320) can eliminate the aforementioned errors by utilizing correction data received from the reference station (200).

[0060] The linear observation equation generated by the GNSS data processing unit (320) is as follows (Equation 1).

[0061] (Mathematical Formula 1)

[0062] Here, y is a residual observation vector with GNSS error removed, which is the residual distance from the GNSS satellite (10) to the GNSS receiver (100), and is a transformation matrix, x is the position of the GNSS receiver (100), λ is the wavelength of the GNSS carrier, N is an initial unknown integer, e is a residual error vector, and Q is a variance-covariance matrix representing the statistical characteristics of the residual error.

[0063] Since vibrations detected by the GNSS receiver (100) appear in the x value in (Equation 1), the initial unknown integer N must be removed in order to estimate the accurate value. To remove the initial unknown integer N, the GNSS data processing unit (320) may apply the OMEGA (Optimal Method for Estimating GNSS Ambiguities) technique, for example. The OMEGA technique is a method for accurately and efficiently estimating integer ambiguities in GNSS data processing.

[0064] Consequently, the linear observation equation after removing the initial unknown constant N is as follows (Equation 2).

[0065] (Mathematical Formula 2)

[0066] Here, is an estimate of the initial unknown integer N, and Is It is the residual error that has changed due to. In reality, since there is no change in the residual error before and after the estimation of the initial unknown value N, the same variance-covariance matrix Q of the residual observations is applied.

[0067] The GNSS data processing unit (320) can generate time series data from (Equation 2).

[0068] The time series data may be observation domain time series data. Generally, since the position x of the GNSS receiver (100) is expressed in three-dimensional space, at least three adjusted carrier phase observations of the aforementioned (Equation 2) are required. However, due to field conditions, there may be cases where a sufficient number of GNSS satellites (10) cannot be observed, and the estimated position of the GNSS receiver (100) known in advance Oscillations can be estimated with only a single observation using [this method]. The observation domain time series data is as follows (Equation 3).

[0069] (Mathematical Formula 3)

[0070] Here, the subscript i is a subscript representing a specific GNSS satellite (10), y is a residual distance between the GNSS satellite (10) and the GNSS receiver (100) as a residual observation vector with GNSS error removed, and λ is the wavelength of the GNSS carrier wave. is an estimate of the initial unknown vector, and is the transpose of transformation matrix A, which is a vector for the corresponding satellite, and is the estimated position of the GNSS receiver (100), and e” is the change in a physical quantity (i.e., the signal transmission distance between the GNSS satellite (10) and the GNSS receiver (100)) that appears in the observation direction of the GNSS satellite (10) due to vibration along with the residual error (e). When using observation value domain time series data, the magnitude and direction of the vibration cannot be known, and only the period of the vibration can be estimated.

[0071] The time series data may be position value domain time series data. When carrier signals are received from a sufficient number (three or more) of GNSS satellites (10), it is possible to directly estimate the position of the GNSS receiver (100) through the position value domain time series data as shown in the following (Equation 4).

[0072] (Mathematical Formula 4)

[0073] Here, is the position estimate of the GNSS receiver (100), and is a transformation matrix, and is a transformation matrix It is the transpose matrix of, y is the residual observation vector with GNSS error removed, i.e., the residual distance from the GNSS satellite (10) to the GNSS receiver (100), and λ is the wavelength of the GNSS carrier wave, and is an estimate of the initial unknown vector. When using position value domain time series data, it is possible to estimate the magnitude, period, and direction of the vibration. This can be viewed as a function similar to a 3-axis accelerometer, but unlike a 3-axis accelerometer, it has the advantage of not requiring alignment and calibration of each axis.

[0074] The vibration estimation unit (330) can estimate vibrations through spectrum analysis of time series data generated by the GNSS data processing unit (320). As an example, the Lomb-Scargle Periodogram technique can be applied as spectrum analysis. The Lomb-Scargle Periodogram technique is the most suitable technique for unevenly sampled data. The Lomb-Scargle Periodogram technique operates by fitting a sine wave model for a specific frequency in the given data using the weighted least squares method.

[0075] The vibration estimation unit (330) has the characteristic of maintaining the continuity of vibration analysis by selectively processing observation value area time series data and position value area time series data according to field conditions. As described above, when using observation value area time series data, the vibration estimation unit (330) can only estimate the vibration period, but when using position value area time series data, the vibration estimation unit (330) can estimate the vibration magnitude, period, and direction. The vibration estimation unit (330) can also detect vibrations with an amplitude of several mm based on the carrier signal of the GNSS satellite (10).

[0076] FIG. 3 is an example of a parameter setting window for a vibration parameter control unit (340) of a GNSS vibration measurement system according to an embodiment of the present disclosure.

[0077] In one embodiment, the vibration measurement processor unit (300) may further include a vibration parameter control unit (340). The vibration parameter control unit (340) functions to set parameters for spectrum analysis performed by the vibration estimation unit (330). Referring to FIG. 3, a user can input parameters for spectrum analysis through a parameter setting window on a user terminal. The vibration parameter control unit (340) sets parameters for spectrum analysis input from the user terminal and transmits them to the vibration estimation unit (330), and the vibration estimation unit (330) can perform spectrum analysis based on the parameters for spectrum analysis transmitted from the vibration parameter control unit (340). The parameters for spectrum analysis may be at least one of the size of time series data, frequency band, number of vibration signals to be detected, vibration detection reliability, noise level, and vibration direction.

[0078] The size of the time series data is the size of the time series data to be used for spectrum analysis, and is the observation value of the GNSS satellite (10) of the GNSS receiver (100) detected over a certain period of time. For example, the certain period of time may be 1 second, 2 seconds, 3 seconds, etc., but is not limited thereto. The frequency band is a parameter for setting an environment that allows spectrum analysis to be performed only within a specific frequency band. The number of vibration signals to be detected, the vibration detection reliability, and the noise level are factors that affect the Lomb-Scargle Periodogram technique used for spectrum analysis. The number of vibration signals to be detected is a setting for the number of vibration signals to be detected in spectrum analysis, the vibration detection reliability is a setting for the reliability of the result of the vibration estimation unit (330) estimating the vibration, and the noise level is a setting for the noise that must be considered during spectrum analysis. The vibration direction is a parameter selected to estimate one of the vibrations of the 1st axis, 2nd axis, or 3rd axis.

[0079] In one embodiment, the vibration measurement processor unit (300) may further include a multicasting unit (350). The multicasting unit (350) has the function of transmitting vibration information estimated by the vibration estimation unit (330) to a user terminal via the network (20).

[0080]

[0081] The disclosed content is merely illustrative and can be modified and implemented in various ways by a person skilled in the art without departing from the gist of the claim in the patent claims; therefore, the scope of protection of the disclosed content is not limited to the specific embodiments described above.

[0082]

[0083] Explanation of the symbols

[0084] 10: GNSS satellite

[0085] 20: Network

[0086] 100: GNSS receiver

[0087] 200: Standard country

[0088] 300: Vibration measurement processor unit

[0089] 310: Interface section

[0090] 320: GNSS Data Processing Unit

[0091] 330: Vibration Estimation Unit

[0092] 340: Vibration Parameter Control Unit

[0093] 350: Multicasting section

[0094] The GNSS vibration measurement system of the present disclosure can be used in industrial fields to diagnose the safety of structures by measuring the vibrations of structures such as bridges and buildings.

Claims

1. GNSS receiver; A reference station providing observations from GNSS satellites; and A GNSS vibration measurement system comprising: a vibration measurement processor unit communicating with the above-mentioned GNSS receiver and the above-mentioned reference station via a network; The above vibration measurement processor unit An interface unit communicating with the above-mentioned reference station and the above-mentioned GNSS receiver; A GNSS data processing unit that generates a linear observation equation and generates time series data by processing the observation values ​​of the GNSS satellite received from the GNSS receiver and the reference station and removing errors; and A GNSS vibration measurement system comprising: a vibration estimation unit that estimates vibration information through spectrum analysis of the time series data generated from the GNSS data processing unit.

2. In Claim 1, A GNSS vibration measurement system characterized in that the above linear observation equation is calculated by the following formula: (formula) (formula) Here, y is the residual observation vector with GNSS error removed, is the transformation matrix, x is the location of the GNSS receiver, λ is the wavelength of the GNSS carrier, N is an initial unknown integer, e is the residual error vector Q is the variance-covariance matrix representing the statistical characteristics of the residual error.

3. In Claim 1, A GNSS vibration measurement system characterized by the above time series data being observation domain time series data and calculated by the following formula: (formula) Here, the subscript i is a subscript representing a specific GNSS satellite, y is the residual observation vector with GNSS error removed, λ is the wavelength of the GNSS carrier, is the estimated value of the initial unknown vector, is the transpose of the transformation matrix A, which is the vector for the corresponding satellite, is the estimated position of the GNSS receiver, e” is the change in a physical quantity (i.e., the signal transmission distance between the GNSS satellite and the GNSS receiver) that appears in the observation direction of the GNSS satellite due to oscillation, along with the residual error (e).

4. In Claim 1, A GNSS vibration measurement system characterized by the above time series data being position value domain time series data and calculated by the following formula: (formula) Here, is the GNSS receiver's position estimate, is the transformation matrix, Is The transpose of, y is the residual observation vector with GNSS error removed, λ is the wavelength of the GNSS carrier, is the estimated value of the initial unknown vector is the inverse of Q 5. In Claim 1, A GNSS vibration measurement system characterized by the above spectrum analysis being a Lomb-Scargle Periodogram technique.

6. In Claim 1, The above vibration measurement processor unit further includes a vibration parameter control unit, and A GNSS vibration measurement system characterized in that the vibration parameter control unit sets parameters for the spectrum analysis performed by the vibration estimation unit.

7. In Claim 6, A GNSS vibration measurement system characterized in that the above parameters include at least one of the size of time series data, frequency band, number of vibration signals to be detected, vibration detection reliability, noise level, and vibration direction.

8. In Claim 1, The above vibration measurement processor unit further includes a multicasting unit, and A GNSS vibration measurement system characterized by the above-mentioned multicasting unit transmitting the estimated vibration information to a user terminal via a network.

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