Antenna phase center calibration method and system, terminal and readable storage medium

Abstract

The invention provides an antenna phase center calibration method and system, a terminal and a readable storage medium. The method comprises the following steps: collecting carrier phase observation data corresponding to a to-be-tested antenna and a reference antenna; calculating a non-geometric distance combination observation value of the to-be-measured antenna and a non-geometric distance combination observation value of the reference antenna; subtracting the non-geometric distance combination observation value of the to-be-measured antenna at the corresponding frequency from the non-geometric distance combination observation value of the reference antenna to obtain an initial difference combination observation value, obtaining a non-cycle-slip difference combination observation value in combination with a preset cycle slip threshold, and constructing a target difference combination observation value; fitting a phase center change model corresponding to the to-be-tested antenna based on the target differential combination observation value and a preset satellite; and calibrating the phase center of a to-be-tested antenna based on the phase center change model. The antenna phase center calibration is completed by eliminating external error interference and fitting the phase center change model, and the antenna phase calibration accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antenna calibration, and particularly relates to an antenna phase center calibration method and system, a terminal and a readable storage medium. BACKGROUND

[0002] A GNSS antenna is a core component for signal reception in a satellite navigation system. The observation value obtained by observing a satellite through the GNSS antenna is the distance from the satellite phase center to the position of the GNSS antenna phase center. Since the phase centers of the GNSS antenna for different satellites and different frequencies are not at the same position, and there is a certain deviation in the installation process of the GNSS antenna, how to accurately calibrate the antenna phase center becomes a technical problem to be solved at present.

[0003] At present, the existing antenna phase center deviation mainly includes a phase center offset PCO and a phase center variation PCV. The phase center offset PCO for a certain frequency of the GNSS antenna is generally in the order of centimeters to decimeters, and the value is large, which can be provided by the manufacturer. However, the information of the phase center variation PCV is usually missing when the existing technology publishes an antenna file. Therefore, the existing technology cannot eliminate external errors such as clock differences of ground receivers when calibrating the GNSS antenna phase center, thereby resulting in the problem of poor antenna phase calibration accuracy. SUMMARY

[0004] In order to solve the above problems, the present application provides an antenna phase center calibration method, system, terminal and readable storage medium, which realizes the calibration of the antenna phase center by eliminating external error interference and fitting a phase center variation model, and improves the antenna phase calibration accuracy.

[0005] To achieve the above object, the embodiment of the present application provides an antenna phase center calibration method, which is applied to a to-be-tested antenna and a reference antenna, the to-be-tested antenna and the reference antenna are arranged at a preset geometric distance, and the antenna phase center calibration method comprises the following steps: observing a preset satellite by the to-be-tested antenna and the reference antenna respectively, collecting to-be-tested antenna carrier phase observation data and reference antenna carrier phase observation data; calculating the frequency domain difference of the to-be-tested antenna carrier phase observation data to obtain to-be-tested antenna geometry-free distance combination observation values; calculating the frequency domain difference of the reference antenna carrier phase observation data to construct reference antenna geometry-free distance combination observation values; subtracting the to-be-tested antenna geometry-free distance combination observation values corresponding to the frequency from the reference antenna geometry-free distance combination observation values to obtain initial differential combination observation values; obtaining non-cycle slip differential combination observation values based on a preset cycle slip threshold and the initial differential combination observation values; constructing target differential combination observation values based on the non-cycle slip differential combination observation values; fitting a phase center variation model corresponding to the to-be-tested antenna based on the target differential combination observation values and the preset satellite; and calibrating the phase center of the to-be-tested antenna based on the phase center variation model.

[0006] The embodiment of the present application provides an antenna phase center calibration method, which is applied to a to-be-tested antenna and a reference antenna, the to-be-tested antenna and the reference antenna are arranged at a preset geometric distance, and the antenna phase center calibration method comprises the following steps: observing a preset satellite by the to-be-tested antenna and the reference antenna respectively, collecting to-be-tested antenna carrier phase observation data and reference antenna carrier phase observation data; calculating the frequency domain difference of the to-be-tested antenna carrier phase observation data to obtain to-be-tested antenna geometry-free distance combination observation values; calculating the frequency domain difference of the reference antenna carrier phase observation data to construct reference antenna geometry-free distance combination observation values; subtracting the to-be-tested antenna geometry-free distance combination observation values corresponding to the frequency from the reference antenna geometry-free distance combination observation values to obtain initial differential combination observation values; obtaining non-cycle slip differential combination observation values based on a preset cycle slip threshold and the initial differential combination observation values; constructing target differential combination observation values based on the non-cycle slip differential combination observation values; fitting a phase center variation model corresponding to the to-be-tested antenna based on the target differential combination observation values and the preset satellite; and calibrating the phase center of the to-be-tested antenna based on the phase center variation model.

[0007] Further, the carrier phase observation data of the to-be-tested antenna and the carrier phase observation data of the reference antenna are collected by observing the preset satellite through the to-be-tested antenna and the reference antenna, including: based on the preset observation time length and the preset observation interval, observing the preset satellite through the to-be-tested antenna, recording the geometric distance between the to-be-tested antenna and the preset satellite, the relative clock difference between the to-be-tested antenna and the preset satellite, the phase deviation between the to-be-tested antenna and the preset satellite, the troposphere delay of the to-be-tested antenna corresponding to the frequency, the ionosphere delay of the to-be-tested antenna corresponding to the frequency, the integer ambiguity of the to-be-tested antenna corresponding to the frequency and other noises of the to-be-tested antenna corresponding to the frequency; based on the geometric distance between the to-be-tested antenna and the preset satellite, the relative clock difference between the to-be-tested antenna and the preset satellite, the phase deviation between the to-be-tested antenna and the preset satellite, the troposphere delay of the to-be-tested antenna corresponding to the frequency, the ionosphere delay of the to-be-tested antenna corresponding to the frequency, the integer ambiguity of the to-be-tested antenna corresponding to the frequency and other noises of the to-be-tested antenna corresponding to the frequency, the carrier phase observation data of the to-be-tested antenna is constructed; based on the preset observation time length and the preset observation interval, observing the preset satellite through the reference antenna, recording the geometric distance between the reference antenna and the preset satellite, the relative clock difference between the reference antenna and the preset satellite, the phase deviation between the reference antenna and the preset satellite, the troposphere delay of the reference antenna corresponding to the frequency, the ionosphere delay of the reference antenna corresponding to the frequency, the integer ambiguity of the reference antenna corresponding to the frequency and other noises of the reference antenna corresponding to the frequency; based on the observation of the preset satellite through the reference antenna, the geometric distance between the reference antenna and the preset satellite, the relative clock difference between the reference antenna and the preset satellite, the phase deviation between the reference antenna and the preset satellite, the troposphere delay of the reference antenna corresponding to the frequency, the ionosphere delay of the reference antenna corresponding to the frequency, the integer ambiguity of the reference antenna corresponding to the frequency and other noises of the reference antenna corresponding to the frequency are recorded, and the carrier phase observation data of the reference antenna is constructed.

[0008] In the above scheme, the preset satellite is observed with the preset observation time length and the preset observation interval, and the geometric distance, the relative clock difference, the phase deviation, the troposphere delay, the ionosphere delay, the integer ambiguity and other noises between the to-be-tested antenna and the reference antenna and the satellite are recorded. The structured carrier phase observation data is constructed by collecting external errors, which provides a reliable data basis for subsequent external error separation, helps to complete the antenna phase center calibration by eliminating external error interference and fitting the phase center variation model, and improves the antenna phase calibration accuracy.

[0009] Further, the frequency domain difference of the carrier phase observation data of the to-be-tested antenna is calculated to obtain the non-geometric distance combined observation value of the to-be-tested antenna, including: the carrier phase observation data of the to-be-tested antenna is subtracted in the frequency domain to obtain the phase bias frequency domain difference of the to-be-tested antenna and the preset satellite, the ionospheric delay frequency domain difference corresponding to the frequency of the to-be-tested antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the to-be-tested antenna, and the other noise frequency domain difference corresponding to the frequency of the to-be-tested antenna; the phase bias frequency domain difference of the to-be-tested antenna and the preset satellite, the ionospheric delay frequency domain difference corresponding to the frequency of the to-be-tested antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the to-be-tested antenna, and the other noise frequency domain difference corresponding to the frequency of the to-be-tested antenna are summed to obtain the non-geometric distance combined observation value of the to-be-tested antenna. Further, the frequency domain difference of the carrier phase observation data of the reference antenna is calculated to construct the non-geometric distance combined observation value of the reference antenna, including: the carrier phase observation data of the reference antenna is subtracted in the frequency domain to obtain the phase bias frequency domain difference of the reference antenna and the preset satellite, the ionospheric delay frequency domain difference corresponding to the frequency of the reference antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the reference antenna, and the other noise frequency domain difference corresponding to the frequency of the reference antenna; the phase bias frequency domain difference of the reference antenna and the preset satellite, the ionospheric delay frequency domain difference corresponding to the frequency of the reference antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the reference antenna, and the other noise frequency domain difference corresponding to the frequency of the reference antenna are summed to obtain the non-geometric distance combined observation value of the reference antenna.

[0010] In the above scheme, the carrier phase observation data corresponding to the to-be-tested antenna and the reference antenna is subtracted in the frequency domain, the errors irrelevant to the frequency such as geometric distance, clock difference and tropospheric delay are eliminated, the frequency domain difference of the ionospheric delay, the integer ambiguity, the phase bias and other noises is retained, and the non-geometric distance combined observation value of the to-be-tested antenna is obtained by summing. By eliminating the external errors irrelevant to the frequency, the dominant position of the phase center change related error is highlighted, and the data dimension is reduced, which is helpful for subsequent antenna phase center calibration by eliminating the external error interference and fitting the phase center change model, and improves the antenna phase calibration accuracy.

[0011] Further, based on the preset cycle slip threshold and the initial differential combined observation value, the non-cycle slip differential combined observation value is obtained, including: the initial differential combined observation value is traversed based on the preset data interval, and the local standard deviation of the initial differential combined observation value is calculated; if the local standard deviation meets the preset cycle slip threshold, the initial differential combined observation value located in the middle of the preset data interval is taken as the non-cycle slip differential combined observation value.

[0012] In the above scheme, the initial differential combined observation values are traversed, the local standard deviation of the continuous data segment is calculated, and compared with the threshold value, the data segment where the cycle slip occurs is dynamically identified and removed, and the differential combined observation values without cycle slip are obtained. Thus, the influence of external error on the antenna phase center variation is further reduced, which is helpful for subsequent elimination of external error interference and fitting of the phase center variation model to complete the antenna phase center calibration, and improves the antenna phase calibration accuracy.

[0013] Further, the target differential combined observation values are constructed based on the differential combined observation values without cycle slip, including: calculating the mean value of the initial differential combined observation values based on the initial differential combined observation values; and subtracting the mean value of the initial differential combined observation values from the differential combined observation values without cycle slip to obtain the target differential combined observation values.

[0014] In the above scheme, the mean value of the initial differential combined observation values is calculated, and the target differential combined observation values are obtained by subtracting the mean value of the initial differential combined observation values from the differential combined observation values without cycle slip. In the case without cycle slip, the mean value of the initial differential combined observation values can offset the error term related to the frequency, and then effectively eliminate the remaining external error, which provides a reliable data basis for subsequent fitting of the phase center variation model, and is helpful for improving the antenna phase calibration accuracy.

[0015] Further, the phase center variation model corresponding to the antenna to be measured is fitted based on the target differential combined observation values and the preset satellite, including: obtaining the satellite elevation angle and target differential combined observation value change relationship data set by polynomial regression fitting based on the preset satellite; and fitting the phase center variation model corresponding to the antenna to be measured based on the preset phase center variation parameter set and the satellite elevation angle and target differential combined observation value change relationship data set.

[0016] In the above scheme, the change relationship between the target differential combined observation values and the satellite elevation angle is fitted by polynomial regression, and then the phase center variation model corresponding to the antenna to be measured is fitted in combination with the preset phase center variation parameter set. Thus, the nonlinear characteristics between the phase center variation and the satellite elevation angle are effectively obtained, which is used for subsequent calibration of the phase center of the antenna to be measured. The antenna phase center calibration is completed by eliminating the external error interference and fitting the phase center variation model, and the antenna phase calibration accuracy is improved.

[0017] The embodiment of the present application also provides an antenna phase center calibration system, comprising: a data acquisition module, a first non-geometric distance combined observation value acquisition module, a second non-geometric distance combined observation value acquisition module, an initial differential combined observation value acquisition module, a non-cycle slip differential combined observation value acquisition module, a target differential combined observation value acquisition module, a phase center variation model construction module and a phase center calibration module; the data acquisition module is used for observing a preset satellite by a to-be-tested antenna and a reference antenna respectively, and acquiring to-be-tested antenna carrier phase observation data and reference antenna carrier phase observation data; the first non-geometric distance combined observation value acquisition module is used for calculating the frequency domain difference of the to-be-tested antenna carrier phase observation data, and obtaining to-be-tested antenna non-geometric distance combined observation values; the second non-geometric distance combined observation value acquisition module is used for calculating the frequency domain difference of the reference antenna carrier phase observation data, and constructing reference antenna non-geometric distance combined observation values; the initial differential combined observation value acquisition module is used for subtracting the to-be-tested antenna non-geometric distance combined observation values corresponding to a frequency from the reference antenna non-geometric distance combined observation values, and obtaining initial differential combined observation values; the non-cycle slip differential combined observation value acquisition module is used for obtaining non-cycle slip differential combined observation values based on a preset cycle slip threshold and the initial differential combined observation values; the target differential combined observation value acquisition module is used for constructing target differential combined observation values based on the non-cycle slip differential combined observation values; the phase center variation model construction module is used for fitting a phase center variation model corresponding to the to-be-tested antenna based on the target differential combined observation values and the preset satellite; and the phase center calibration module is used for calibrating the phase center of the to-be-tested antenna based on the phase center variation model.

[0018] The embodiment of the present application provides an antenna phase center calibration system, which sets the to-be-tested antenna and the reference antenna within a preset geometric distance range, and collects corresponding carrier phase observation data by observing a preset satellite by the to-be-tested antenna and the reference antenna. Then, the carrier phase observation data is subtracted in the frequency domain to obtain non-geometric distance combined observation values corresponding to the to-be-tested antenna and the reference antenna. The non-geometric distance combined observation values corresponding to the to-be-tested antenna and the reference antenna are also subjected to differential processing to obtain initial differential combined observation values. Through the subtraction in the frequency domain and the differential processing, most external errors can be effectively eliminated, the complex observation equation is simplified into an error term mainly caused by phase center variation, and then the target differential combined observation values are obtained by combining a cycle slip detection mechanism. Finally, the phase center variation model corresponding to the to-be-tested antenna is fitted to calibrate the phase center of the to-be-tested antenna. Thus, the antenna phase center calibration is completed by eliminating external error interference and fitting the phase center variation model, and the antenna phase calibration accuracy is improved.

[0019] The embodiment of the present application provides an antenna phase center calibration terminal, which comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor. When the computer program is executed by the processor, an antenna phase center calibration method is implemented.

[0020] The embodiment of the present application provides an antenna phase center calibration readable storage medium, and the readable storage medium comprises a stored computer program, wherein the readable storage medium controls a device to execute an antenna phase center calibration method when the computer program runs. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A step flowchart of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure; Figure 2 A reference antenna and a to-be-measured antenna setting diagram of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure; Figure 3 A GPS satellite sky map diagram of a reference antenna and a to-be-measured antenna of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure Figure 1 ; Figure 4 A GPS satellite sky map diagram of a reference antenna and a to-be-measured antenna of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure Figure 2 ; Figure 5 A G24 satellite signal geometry-free distance combination observation value statistical diagram of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure; Figure 6 A G24 satellite signal initial differential combination observation value statistical diagram of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure; Figure 7 A G24 satellite signal target differential combination observation value statistical diagram of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure; Figure 8 A satellite elevation angle and target differential combination observation value fitting diagram of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure; Figure 9 A to-be-measured antenna phase center change fitting value and real value difference diagram of an antenna phase center calibration method provided by an embodiment of the present application is shown in the figure, wherein, Figure 9 (a) of the figure is a to-be-measured antenna phase center change fitting value column diagram of an antenna phase center calibration method provided by an embodiment of the present application; Figure 9 (b) of the figure is a to-be-measured antenna phase center change real value column diagram of an antenna phase center calibration method provided by an embodiment of the present application; Figure 9 (c) of the figure is a to-be-measured antenna phase center change real value and fitting value difference column diagram of an antenna phase center calibration method provided by an embodiment of the present application. Figure 10 A module structure schematic diagram of an antenna phase center calibration system is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] Embodiment 1 Reference Figure 1 , Figure 1 A step flowchart of an antenna phase center calibration method is provided for an embodiment of the present application. As shown in Figure 1 The present application proposes an antenna phase center calibration method applied to a to-be-measured antenna and a reference antenna, the to-be-measured antenna and the reference antenna are arranged at a preset geometric distance, the antenna phase center calibration method comprises steps 101 to 108, and each step is specifically as follows: Step 101, the to-be-measured antenna and the reference antenna are used to observe a preset satellite respectively, and to-be-measured antenna carrier phase observation data and reference antenna carrier phase observation data are collected; Step 102, a frequency domain difference of the to-be-measured antenna carrier phase observation data is calculated to obtain to-be-measured antenna geometry-free distance combination observation values; Step 103, a frequency domain difference of the reference antenna carrier phase observation data is calculated to construct reference antenna geometry-free distance combination observation values; Step 104, the to-be-measured antenna geometry-free distance combination observation values corresponding to the frequency are subtracted from the reference antenna geometry-free distance combination observation values to obtain initial differential combination observation values; Step 105, based on a preset cycle slip threshold and the initial differential combination observation values, non-cycle slip differential combination observation values are obtained; Step 106, target differential combination observation values are constructed based on the non-cycle slip differential combination observation values; Step 107, based on the target differential combination observation values and the preset satellite, a phase center variation model corresponding to the to-be-measured antenna is fitted; Step 108, the phase center of the to-be-measured antenna is calibrated based on the phase center variation model.

[0024] A specific implementable manner is shown in Figure 2 , Figure 2 A reference antenna and a to-be-measured antenna setting schematic diagram of an antenna phase center calibration method is provided for an embodiment of the present application. As shown in Figure 2As shown, in the embodiment, taking the GNSS antenna as an example for explanation, in order to accurately describe the coordinates of the station millimeter level, it is necessary to apply the antenna parameters of each phase center for calibration, and to reduce each phase center to the same physical position at the bottom, generally set at the center of the circular base of the antenna, which is called the antenna reference point ARP (Antenna Reference Point), and a reference antenna A with a known PCV and a to-be-measured antenna B with an unknown PCV at a certain frequency are erected at the same time, and the two antennas are set apart by a predetermined geometric distance, in the embodiment, the two antennas constitute a short baseline, the reference antenna A and the to-be-measured antenna B are set apart by 7m, the satellite S is observed by the reference antenna A and the to-be-measured antenna B, and the satellite S is preset in the embodiment, then the single-carrier phase observation data of the reference antenna A and the to-be-measured antenna B is collected, which is in the unit of length; then the double-frequency carrier phase observation values of the reference antenna A and the to-be-measured antenna B are used to construct geometry-free (Geometry-Free, GF) combination observation values, which can eliminate the influence of geometric distance, clock difference and troposphere delay in the frequency domain; since the distance between the reference antenna A and the to-be-measured antenna B is close, the ionospheric delay of the corresponding frequency signals is almost the same, therefore, the geometry-free combination observation values of the to-be-measured antenna corresponding to the frequency are subtracted from the geometry-free combination observation values of the reference antenna, that is, the initial differential combination observation values are obtained , so as to eliminate the ionospheric delay; in order to ensure the accuracy of the subsequent fitting results, the data without cycle slip of the reference antenna A and the to-be-measured antenna B are selected to obtain the non-cycle slip differential combination observation values, when the reference antenna A and the to-be-measured antenna B continuously track the satellite S and no cycle slip occurs, the target differential combination observation values are constructed by using the non-cycle slip differential combination observation values, and finally the target differential combination observation values of all satellites are counted , the phase center variation model corresponding to the to-be-measured antenna is fitted according to the change of the satellite elevation angle and the other known PCV parameters provided by igs20.atx, the phase center variation model corresponding to the to-be-measured antenna is provided to calibrate the antenna phase center with 1mm precision, in the embodiment, the reference antenna A is explained by Trimble (TRIMBLE) TRM57971.00 NONE, and the to-be-measured antenna B is explained by Huachu CHCC220GR2 CHCD, and igs20.atx is an antenna file published by IGS (International GNSS Service).

[0025] The embodiment of the present application provides an antenna phase center calibration method, the antenna to be measured and the reference antenna are arranged within a preset geometric distance range, and the antenna to be measured and the reference antenna observe a preset satellite, corresponding carrier phase observation data is collected, the carrier phase observation data is subtracted in a frequency domain to obtain corresponding non-geometric distance combination observation values of the antenna to be measured and the reference antenna, the non-geometric distance combination observation values of the antenna to be measured and the reference antenna are also subjected to differential processing to obtain initial differential combination observation values, through the subtraction in the frequency domain and the differential processing, most external errors can be effectively eliminated, a complex observation equation is simplified into an error term mainly caused by phase center variation, then the target differential combination observation values are obtained by combining a cycle slip detection mechanism, and finally a phase center variation model corresponding to the antenna to be measured is fitted to calibrate the phase center of the antenna to be measured. Therefore, the antenna phase center calibration is completed by eliminating external error interference and fitting the phase center variation model, and the antenna phase calibration accuracy is improved.

[0026] In a preferred scheme, the antenna to be measured and the reference antenna respectively observe a preset satellite, and antenna to be measured carrier phase observation data and reference antenna carrier phase observation data are collected, including: based on a preset observation time length and a preset observation interval, the antenna to be measured observes the preset satellite, and the geometric distance between the antenna to be measured and the preset satellite, the relative clock difference between the antenna to be measured and the preset satellite, the phase deviation between the antenna to be measured and the preset satellite, the troposphere delay of the antenna to be measured corresponding to a frequency, the ionosphere delay of the antenna to be measured corresponding to a frequency, the integer ambiguity of the antenna to be measured corresponding to a frequency and other noises of the antenna to be measured corresponding to a frequency are recorded; based on the geometric distance between the antenna to be measured and the preset satellite, the relative clock difference between the antenna to be measured and the preset satellite, the phase deviation between the antenna to be measured and the preset satellite, the troposphere delay of the antenna to be measured corresponding to a frequency, the ionosphere delay of the antenna to be measured corresponding to a frequency, the integer ambiguity of the antenna to be measured corresponding to a frequency and other noises of the antenna to be measured corresponding to a frequency, the antenna to be measured carrier phase observation data is constructed; based on the preset observation time length and the preset observation interval, the reference antenna observes the preset satellite, and the geometric distance between the reference antenna and the preset satellite, the relative clock difference between the reference antenna and the preset satellite, the phase deviation between the reference antenna and the preset satellite, the troposphere delay of the reference antenna corresponding to a frequency, the ionosphere delay of the reference antenna corresponding to a frequency, the integer ambiguity of the reference antenna corresponding to a frequency and other noises of the reference antenna corresponding to a frequency are recorded; based on the observation of the reference antenna to the preset satellite, the geometric distance between the reference antenna and the preset satellite, the relative clock difference between the reference antenna and the preset satellite, the phase deviation between the reference antenna and the preset satellite, the troposphere delay of the reference antenna corresponding to a frequency, the ionosphere delay of the reference antenna corresponding to a frequency, the integer ambiguity of the reference antenna corresponding to a frequency and other noises of the reference antenna corresponding to a frequency are recorded, and the reference antenna carrier phase observation data is constructed.

[0027] In an implementation of the preferred solution, the satellite S is observed by a reference antenna A and a to-be-measured antenna B, the satellite is preset to be satellite S in the embodiment, and then single-epoch carrier phase observation data of the reference antenna A and the to-be-measured antenna B is collected, which is in a length unit; specifically, the data recording interval of the reference antenna A and the to-be-measured antenna B is set to be 30 s, the cut-off elevation angle is 10°, static measurement is performed at the same time, and the continuous observation duration is 24 h; and the carrier phase observation equation corresponding to the satellite S to the reference antenna A and the to-be-measured antenna B is as follows: ; ; In the formula, is the carrier phase observation value of the reference antenna A corresponding to the frequency; is the carrier phase observation value of the to-be-measured antenna B corresponding to the frequency, is the geometric distance of the reference antenna A and the to-be-measured antenna B to the satellite S respectively, is the light speed, is the relative clock difference of the reference antenna A and the to-be-measured antenna B to the satellite S respectively, is the tropospheric delay of the reference antenna A and the to-be-measured antenna B respectively, is the ionospheric delay of the reference antenna A corresponding to the frequency; is the ionospheric delay of the to-be-measured antenna B corresponding to the frequency, is the carrier wavelength corresponding to the frequency respectively, is the integer ambiguity of the reference antenna A corresponding to the frequency; is the integer ambiguity of the to-be-measured antenna B corresponding to the frequency, is the phase deviation of the reference antenna A and the to-be-measured antenna B and the satellite S caused by the hardware delay on the corresponding frequency respectively, is other noise of the reference antenna A corresponding to the frequency; is other noise of the to-be-measured antenna B corresponding to the frequency, in the embodiment, for the GNSS receiver, only the carrier phase observation value can be measured, that is, in the formula , , other parameters exist in theory, but are difficult to measure and separate, and cannot be directly obtained, therefore, twice difference is performed subsequently to eliminate them, so as to fit the PCV parameter of the to-be-measured antenna; in addition, since the observation environment is good, the other noise mainly contains the error caused by the PCV.

[0028] Referring to Figure 3 and Figure 4 , Figure 3 is a GPS satellite sky map diagram of a reference antenna and a to-be-measured antenna of an antenna phase center calibration method provided in an embodiment of the application Figure 1 ; Figure 4A reference antenna of an antenna phase center calibration method provided for an embodiment of the application and a to-be-measured antenna GPS satellite sky map diagram Figure 2 ; as Figure 3 and Figure 4 shown, since the reference antenna A and the to-be-measured antenna B are arranged close, Figure 3 the GPS satellite sky map of the reference antenna A shown and Figure 4 the GPS satellite sky map of the to-be-measured antenna B shown are basically consistent with the GPS satellites that can be observed, and the elevation angle and azimuth angle of the same satellite are also basically the same for different antennas, which is beneficial to the calculation of the non-geometric distance combination observation value, and it is worth mentioning that Figure 3 and Figure 4 each gray curve in and corresponds to the running track of a satellite.

[0029] In the above scheme, the preset satellite is observed for a preset observation time and a preset observation interval, and the geometric distance between the to-be-measured antenna and the reference antenna and the satellite, the relative clock error, the phase deviation, the troposphere delay, the ionosphere delay, the integer ambiguity and other noise parameters are recorded, the structured carrier phase observation data is constructed by collecting external errors, a reliable data basis is provided for subsequent external error separation, which is helpful to complete the antenna phase center calibration by eliminating external error interference and fitting the phase center change model, and improve the antenna phase calibration accuracy.

[0030] A preferred scheme, calculating the frequency domain difference of the to-be-measured antenna carrier phase observation data to obtain the non-geometric distance combination observation value of the to-be-measured antenna, comprising: differencing the to-be-measured antenna carrier phase observation data in the frequency domain to obtain the phase deviation frequency domain difference between the to-be-measured antenna and the preset satellite, the ionosphere delay frequency domain difference corresponding to the frequency of the to-be-measured antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the to-be-measured antenna and the other noise frequency domain difference corresponding to the frequency of the to-be-measured antenna; summing the phase deviation frequency domain difference between the to-be-measured antenna and the preset satellite, the ionosphere delay frequency domain difference corresponding to the frequency of the to-be-measured antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the to-be-measured antenna and the other noise frequency domain difference corresponding to the frequency of the to-be-measured antenna to obtain the non-geometric distance combination observation value of the to-be-measured antenna. Further, the frequency domain difference of the reference antenna carrier phase observation data is calculated to construct the non-geometric distance combination observation value of the reference antenna, comprising: differencing the reference antenna carrier phase observation data in the frequency domain to obtain the phase deviation frequency domain difference between the reference antenna and the preset satellite, the ionosphere delay frequency domain difference corresponding to the frequency of the reference antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the reference antenna and the other noise frequency domain difference corresponding to the frequency of the reference antenna; summing the phase deviation frequency domain difference between the reference antenna and the preset satellite, the ionosphere delay frequency domain difference corresponding to the frequency of the reference antenna, the integer ambiguity frequency domain difference corresponding to the frequency of the reference antenna and the other noise frequency domain difference corresponding to the frequency of the reference antenna to obtain the non-geometric distance combination observation value of the reference antenna.

[0031] In an implementation of the preferred scheme, the double-frequency carrier phase observations of the reference antenna A and the antenna under test B are used to construct geometry-free (GF) combined observations, and the difference in the frequency domain can eliminate the influence of geometry, clock error and tropospheric delay. Specifically, the geometry-free combined observation equations of the reference antenna A and the antenna under test B are as follows: In the formula, are the geometry-free combined observations of the reference antenna A and the antenna under test B for the satellite S, respectively. See Figure 5 , Figure 5 FIG. 1 is a statistical diagram of the geometry-free combined observations of the G24 satellite signals of an antenna phase center calibration method according to an embodiment of the present application; as shown in Figure 5 , specifically shows and dGF change with time, and when no cycle slip occurs, they are basically a horizontal straight line, so it can be proved that by calculating the geometry-free combined observations, the influence of geometry, clock error and tropospheric delay can be eliminated.

[0032] In the above scheme, the carrier phase observation data corresponding to the antenna under test and the reference antenna are subtracted in the frequency domain to eliminate the error terms irrelevant to frequency, such as geometry, clock error and tropospheric delay, and the frequency domain difference of ionospheric delay, integer ambiguity, phase bias and other noise is retained to obtain the geometry-free combined observations of the antenna under test. By eliminating the external errors irrelevant to frequency, the phase center change related errors are highlighted, the data dimension is reduced, which is helpful for subsequent antenna phase center calibration by eliminating external error interference and fitting the phase center change model, and the antenna phase calibration accuracy is improved.

[0033] In a preferred scheme, the non-cycle slip differential combined observations are obtained based on the preset cycle slip threshold and the initial differential combined observations, including: traversing the initial differential combined observations based on the preset data interval, and calculating the local standard deviation of the initial differential combined observations; if the local standard deviation meets the preset cycle slip threshold, the initial differential combined observation located in the middle of the preset data interval is taken as the non-cycle slip differential combined observation.

[0034] In an implementation of the preferred scheme, since the distance between the reference antenna A and the antenna under test B is close, the ionospheric delay of the corresponding frequency signals is almost the same, so the geometry-free combined observations of the antenna under test and the reference antenna corresponding to the frequency are subtracted, that is, the initial differential combined observations are obtained to eliminate the ionospheric delay; specifically, the calculation formula of the initial differential combined observations is as follows: ; in: ; ; In the formula, For reference antenna A and antenna B under test relative to satellite S In this embodiment, the combined observations are represented as the initial difference combined observations; This is a combined value of ambiguity and phase deviation, representing the condition when reference antenna A and antenna B under test continuously track and observe satellite S without cycle slips. Basically unchanged; Other error combinations mainly include the effects of phase center changes. The PCV parameters at the frequency corresponding to reference antenna A; PCV parameters of antenna B at the corresponding frequency. See [link / reference] Figure 6 , Figure 6 A statistical diagram illustrating the initial differential combination observations of G24 satellite signals for an antenna phase center calibration method according to a certain embodiment of the present invention; as shown. Figure 6 As shown, the mean and standard deviation were quantitatively calculated, where the mean is represented by 'mean' and the standard deviation by 'std'. The stable data distribution and small standard deviation demonstrate that the initial difference combination of observations was successfully calculated. It can eliminate ionospheric delay.

[0035] To ensure the accuracy of subsequent fitting results, it is necessary to select data from both the reference antenna A and the antenna under test B that have no cycle slips, thus obtaining cycle slip-free differential combination observations. Specifically, within a preset data interval, initial differential combination observations are calculated. For each data interval, the local standard deviation is calculated. When the local standard deviation is less than a preset cycle slip threshold (in this embodiment, the preset cycle slip threshold is 0.010m), the observed data in that data interval is considered to have no cycle slip. The initial difference combination observation located in the middle of the preset data interval is then used as the cycle slip-free difference combination observation. Taking 11 consecutive local standard deviations as an example, when the local standard deviation is less than the preset cycle slip threshold, the data from the 6th epoch is added to the target difference combination observation. The calculation is performed, otherwise the epoch is discarded, until the entire data segment is traversed.

[0036] In the above scheme, the initial differential combined observation values are traversed, the local standard deviation of the continuous data segment is calculated, and compared with the threshold value to dynamically identify and eliminate the data segment where the cycle slip occurs, and the differential combined observation values without cycle slip are obtained. Thus, the influence of the external error on the antenna phase center variation is further reduced, which is helpful for subsequent elimination of the external error interference and fitting of the phase center variation model to complete the antenna phase center calibration and improve the antenna phase calibration accuracy.

[0037] In a preferred scheme, the target differential combined observation values are constructed based on the differential combined observation values without cycle slip, including: calculating the mean value of the initial differential combined observation values based on the initial differential combined observation values; and subtracting the mean value of the initial differential combined observation values from the differential combined observation values without cycle slip to obtain the target differential combined observation values.

[0038] In a preferred scheme, when the reference antenna A and the antenna B to be measured continuously track the satellite S and no cycle slip occurs, the target differential combined observation values are constructed based on the differential combined observation values without cycle slip; specifically, when the reference antenna A and the antenna B to be measured continuously track the satellite S and no cycle slip occurs, are basically unchanged, and are the same as the mean value of the initial differential combined observation values , therefore, in order to eliminate the influence of , the calculation formula of the target differential combined observation values is as follows: ; In the formula, is the target differential combined observation value of the reference antenna A and the antenna B to be measured for the satellite S, in the embodiment, the target differential combined observation value and the target differential combined observation value both represent the initial differential combined observation values.

[0039] In the above scheme, the mean value of the initial differential combined observation values is calculated, and the target differential combined observation values are obtained by subtracting the mean value from the differential combined observation values without cycle slip. In the case without cycle slip, the mean value of the initial differential combined observation values can offset the error term related to the frequency, and then effectively eliminate the remaining external error, which provides a reliable data basis for subsequent fitting of the phase center variation model, and is helpful for improving the antenna phase calibration accuracy.

[0040] In a preferred scheme, based on the target differential combined observation values and the preset satellite, a phase center variation model corresponding to the antenna to be measured is fitted, including: based on the preset satellite, a satellite elevation angle and target differential combined observation value change relationship data set is obtained through polynomial regression fitting; and based on the preset phase center variation parameter set and the satellite elevation angle and target differential combined observation value change relationship data set, the phase center variation model corresponding to the antenna to be measured is fitted.

[0041] In an implementation of the preferred scheme, the target differential combined observation values of all satellites are finally counted With the change of the satellite elevation angle, other known PCV parameters provided by igs20.atx are combined to fit the phase center variation model corresponding to the antenna to be measured. Specifically, refer to Figure 7 , Figure 7 The target differential combined observation value statistical diagram of the G24 satellite signal of an antenna phase center calibration method provided by an embodiment of the application is shown in the figure. Figure 7 The change of the target differential combined observation value with the satellite elevation angle is shown in the figure. The target differential combined observation values of all GPS satellites are counted and the satellite elevation angle, and the calculation formula of the satellite elevation angle and the target differential combined observation value change relationship data set is obtained through polynomial regression fitting as follows: ; ; In the formula, y is the target differential combined observation value, the unit is mm, x is the satellite elevation angle, the unit is °, and the rest are polynomial fitting coefficients. The preset phase center variation parameter set is represented as igs20.atx in this embodiment. The partial antenna phase center models of the reference antenna A and the antenna to be measured B have been published in igs20.atx, as shown in Table 1: Table 1 PCV parameters of the reference antenna A and the antenna to be measured B In Table 1, the PVC parameter of the reference antenna A at the G01 frequency point is represented as , the PVC parameter of the reference antenna A at the G02 frequency point is represented as , the PVC parameter of the antenna to be measured B at the G01 frequency point is represented as , and the PVC parameter of the antenna to be measured B at the G02 frequency point is represented as ; taking the PCV of the antenna to be measured B at the G02 frequency point without considering the azimuth angle (NOAZI) as an example, the single-GPS carrier phase observation value is used to fit the phase center variation model expression corresponding to the antenna to be measured as follows: ; In the above scheme, the change relationship between the target differential combined observation value and the satellite elevation angle is fitted by polynomial regression, and the preset phase center variation parameter set is combined to fit the phase center variation model corresponding to the antenna to be measured. Therefore, the nonlinear characteristics between the phase center variation and the satellite elevation angle are effectively obtained, which is used for subsequent calibration of the phase center of the antenna to be measured. The antenna phase center calibration is completed by eliminating external error interference and fitting the phase center variation model, and the antenna phase calibration accuracy is improved.

[0042] One possible implementation example involves step 108, which calibrates the phase center of the antenna under test based on a phase center change model. This includes: providing a phase center change result with 1mm accuracy using the phase center change model corresponding to the antenna under test to calibrate the antenna's phase center. Here, igs20.atx is an antenna file published by IGS (International GNSS Service). In this embodiment, see... Figure 8 , Figure 8 This is a schematic diagram illustrating the fitting of satellite elevation angle and target differential combination observations in an antenna phase center calibration method according to a certain embodiment of the present invention; as shown. Figure 8 As shown, in order to verify the rationality of the fitting results of the phase center change model, in Figure 8 The “regression curve” in the text corresponds to the curve obtained by calculating the relationship between the satellite elevation angle and the target difference combination observation value dataset through polynomial regression fitting. The “PCV combination value” corresponds to... The two curves are very close in the 10° to 90° range. Based on the phase center change model obtained from the fitting, and the data in Table 1... Parameters can be fitted to The fitting results for the changes in elevation angle, i.e., the changes in the phase center of the antenna B under test at the G02 frequency, are shown in Table 2: Table 2 Comparison of the true and fitted values ​​of the phase center model of antenna B at frequency G02. See Figure 9 , Figure 9 This is a schematic diagram illustrating the difference between the fitted value and the true value of the phase center change of the antenna under test in an antenna phase center calibration method provided in a certain embodiment of the present invention; as shown. Figure 9 As shown, Figure 9 (a) is a histogram of fitted values ​​of the phase center change of the antenna under test in an antenna phase center calibration method provided in a certain embodiment of the present invention. Figure 9 (a) shows the true values ​​using a bar chart; Figure 9 (b) is a bar chart illustrating the true values ​​of the phase center change of the antenna under test in an antenna phase center calibration method according to a certain embodiment of the present invention. Figure 9 (b) shows the fitted values ​​using a bar chart; Figure 9 (c) is a bar chart illustrating the difference between the true value and the fitted value of the phase center change of the antenna under test in an antenna phase center calibration method provided in a certain embodiment of the present invention. Figure 9 (c) uses a bar chart to show the difference between the true and fitted values; from Figure 9 of (a) Figure 9 (b) andFigure 10 As can be seen in (c), when the satellite elevation angle is below 10° or equal to 90°, the difference between the two is significantly larger. This is because the cutoff satellite elevation angle and the characteristics of satellite operation result in a lack of data when the satellite elevation angle is too low or too high, which makes the fitting effect worse. Therefore, for most normal satellite elevation angle ranges, the difference between the two is better than 1 mm.

[0043] Example 2 See Figure 10 , Figure 10 This is a schematic diagram of the module structure of an antenna phase center calibration system according to a certain embodiment of the present invention. ​ As shown, this embodiment of the invention also provides an antenna phase center calibration system, including: a data acquisition module 201, a first geometric distance-free combined observation value acquisition module 202, a second geometric distance-free combined observation value acquisition module 203, an initial differential combined observation value acquisition module 204, a cycle-slip-free differential combined observation value acquisition module 205, a target differential combined observation value acquisition module 206, a phase center change model construction module 207, and a phase center calibration module 208; the data acquisition module 201 is used to observe a preset satellite through the antenna under test and a reference antenna respectively, and acquire carrier phase observation data of the antenna under test and the carrier phase observation data of the reference antenna; the first geometric distance-free combined observation value acquisition module 202 is used to calculate the frequency domain difference of the carrier phase observation data of the antenna under test to obtain the geometric distance-free combined observation value of the antenna under test; the second geometric distance-free combined observation value acquisition module 203 is used to calculate the frequency domain difference of the carrier phase observation data of the antenna under test to obtain the geometric distance-free combined observation value of the antenna under test; the second geometric distance-free combined observation value acquisition module 204 is used to calculate the geometric distance-free combined observation value of the antenna under test; the second geometric distance-free combined observation value acquisition module 205 is used to calculate the geometric distance-free combined observation value of the antenna under test; the second geometric distance-free combined observation value acquisition module 206 is used to calculate the geometric distance-free combined observation value of the antenna under test; the second geometric distance-free combined observation value acquisition module 207 ...4 is used to calculate the geometric distance-free combined observation value of the antenna under test; the first geometric distance- Module 203 is used to calculate the frequency domain difference of the carrier phase observation data of the reference antenna and construct the geometric distance-free combined observation value of the reference antenna; the initial differential combined observation value acquisition module 204 is used to subtract the geometric distance-free combined observation value of the antenna under test at the corresponding frequency from the geometric distance-free combined observation value of the reference antenna to obtain the initial differential combined observation value; the cycle slip-free differential combined observation value acquisition module 205 is used to obtain the cycle slip-free differential combined observation value based on the preset cycle slip threshold and the initial differential combined observation value; the target differential combined observation value acquisition module 206 is used to construct the target differential combined observation value based on the cycle slip-free differential combined observation value; the phase center change model construction module 207 is used to fit the phase center change model corresponding to the antenna under test based on the target differential combined observation value and the preset satellite; the phase center calibration module 208 is used to calibrate the phase center of the antenna under test based on the phase center change model.

[0044] The embodiment of the present application provides an antenna phase center calibration system, sets a to-be-measured antenna and a reference antenna in a preset geometric distance range, and performs observation on a preset satellite according to the to-be-measured antenna and the reference antenna, collects corresponding carrier phase observation data, then performs difference in a frequency domain on the carrier phase observation data to obtain a no-geometric distance combination observation value corresponding to the to-be-measured antenna and the reference antenna, and performs difference processing on the no-geometric distance combination observation value corresponding to the to-be-measured antenna and the reference antenna to obtain an initial difference combination observation value, through the difference in the frequency domain and the difference processing, most external errors can be effectively eliminated, a complex observation equation is simplified into an error term mainly in phase center variation, then a target difference combination observation value is obtained by combining a cycle slip detection mechanism, and finally a phase center variation model corresponding to the to-be-measured antenna is fitted to calibrate the phase center of the to-be-measured antenna. In this way, the antenna phase center calibration is completed by eliminating external error interference and fitting the phase center variation model, and the antenna phase calibration accuracy is improved.

[0045] The embodiment of the present application provides an antenna phase center calibration terminal, the terminal comprises a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, and the processor implements an antenna phase center calibration method when executing the computer program.

[0046] The embodiment of the present application provides an antenna phase center calibration readable storage medium, the readable storage medium comprises a stored computer program, wherein the readable storage medium controls a device where the readable storage medium is located to execute an antenna phase center calibration method when the computer program runs.

[0047] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.

[0048] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0049] In addition, the terms "first", "second", etc., are used only for the purpose of description, and should not be understood as indicating or implying relative importance or a required number thereof. Thus, features with "first" "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

Claims

1. A method for calibrating the phase center of an antenna, characterized in that, Applied to an antenna under test and a reference antenna, wherein the antenna under test and the reference antenna are set at a preset geometric distance, the antenna phase center calibration method includes: The preset satellite is observed by the antenna under test and the reference antenna respectively, and the carrier phase observation data of the antenna under test and the carrier phase observation data of the reference antenna are collected. Calculate the frequency domain difference of the carrier phase observation data of the antenna under test to obtain the geometric distance-free combined observation value of the antenna under test; Calculate the frequency domain difference of the carrier phase observation data of the reference antenna, and construct the geometric distance-free combined observation values ​​of the reference antenna; The initial differential combination observation value is obtained by subtracting the geometric distance-free combination observation value of the antenna under test at the corresponding frequency from the geometric distance-free combination observation value of the reference antenna. Based on the preset cycle slip threshold and the initial differential combination observations, cycle slip-free differential combination observations are obtained. Target difference combination observations are constructed based on the cycle-slip-free difference combination observations; Based on the target differential combination observations and the preset satellite, a phase center change model corresponding to the antenna under test is fitted; The phase center of the antenna under test is calibrated based on the phase center change model.

2. The antenna phase center calibration method as described in claim 1, characterized in that, The preset satellite is observed through the antenna under test and the reference antenna, respectively, and carrier phase observation data of the antenna under test and the reference antenna are collected, including: Based on a preset observation duration and a preset observation interval, the preset satellite is observed through the antenna under test, and the geometric distance between the antenna under test and the preset satellite, the relative clock difference between the antenna under test and the preset satellite, the phase deviation between the antenna under test and the preset satellite, the tropospheric delay at the frequency corresponding to the antenna under test, the ionospheric delay at the frequency corresponding to the antenna under test, the integer ambiguity at the frequency corresponding to the antenna under test, and other noise at the frequency corresponding to the antenna under test are recorded. Based on the geometric distance between the antenna under test and the preset satellite, the relative clock difference between the antenna under test and the preset satellite, the phase deviation between the antenna under test and the preset satellite, the tropospheric delay at the frequency corresponding to the antenna under test, the ionospheric delay at the frequency corresponding to the antenna under test, the integer ambiguity at the frequency corresponding to the antenna under test, and other noise at the frequency corresponding to the antenna under test, carrier phase observation data of the antenna under test is constructed. Based on the preset observation duration and the preset observation interval, the preset satellite is observed through the reference antenna, and the geometric distance between the reference antenna and the preset satellite, the relative clock difference between the reference antenna and the preset satellite, the phase deviation between the reference antenna and the preset satellite, the tropospheric delay at the frequency corresponding to the reference antenna, the ionospheric delay at the frequency corresponding to the reference antenna, the integer ambiguity at the frequency corresponding to the reference antenna, and other noise at the frequency corresponding to the reference antenna are recorded. Based on the reference antenna, the preset satellite is observed, and the geometric distance between the reference antenna and the preset satellite, the relative clock difference between the reference antenna and the preset satellite, the phase deviation between the reference antenna and the preset satellite, the tropospheric delay at the frequency corresponding to the reference antenna, the ionospheric delay at the frequency corresponding to the reference antenna, the integer ambiguity at the frequency corresponding to the reference antenna, and other noise at the frequency corresponding to the reference antenna are recorded to construct the reference antenna carrier phase observation data.

3. The antenna phase center calibration method as described in claim 2, characterized in that, Calculate the frequency domain difference of the carrier phase observation data of the antenna under test to obtain the geometrically distance-free combined observation values ​​of the antenna under test, including: The carrier phase observation data of the antenna under test are subtracted in the frequency domain to obtain the frequency domain difference of the phase deviation between the antenna under test and the preset satellite, the frequency domain difference of the ionospheric delay at the corresponding frequency of the antenna under test, the frequency domain difference of the integer ambiguity at the corresponding frequency of the antenna under test, and the frequency domain difference of other noise at the corresponding frequency of the antenna under test. The frequency domain difference of the phase deviation between the antenna under test and the preset satellite, the frequency domain difference of the ionospheric delay at the corresponding frequency of the antenna under test, the frequency domain difference of the integer ambiguity at the corresponding frequency of the antenna under test, and the frequency domain difference of other noise at the corresponding frequency of the antenna under test are summed to obtain the geometrically distance-free combined observation value of the antenna under test.

4. The antenna phase center calibration method as described in claim 2, characterized in that, Calculate the frequency domain difference of the carrier phase observation data of the reference antenna to construct a geometrically distance-free combined observation value of the reference antenna, including: The carrier phase observation data of the reference antenna are subtracted in the frequency domain to obtain the frequency domain difference of the phase deviation between the reference antenna and the preset satellite, the frequency domain difference of the ionospheric delay at the corresponding frequency of the reference antenna, the frequency domain difference of the integer ambiguity at the corresponding frequency of the reference antenna, and the frequency domain difference of other noise at the corresponding frequency of the reference antenna. The frequency domain difference of the phase deviation between the reference antenna and the preset satellite, the frequency domain difference of the ionospheric delay at the corresponding frequency of the reference antenna, the frequency domain difference of the integer ambiguity at the corresponding frequency of the reference antenna, and the frequency domain difference of other noise at the corresponding frequency of the reference antenna are summed to obtain the geometrically distance-free combined observation value of the reference antenna.

5. The antenna phase center calibration method as described in claim 1, characterized in that, Based on the preset cycle slip threshold and the initial differential combination observations, cycle slip-free differential combination observations are obtained, including: The initial difference combination observations are iterated through at preset data intervals, and the local standard deviation of the initial difference combination observations is calculated. If the local standard deviation meets the preset cycle slip threshold, then the initial difference combination observation located in the middle of the preset data interval is taken as the cycle slip-free difference combination observation.

6. The antenna phase center calibration method as described in claim 5, characterized in that, Constructing target difference combination observations based on the cycle-slip-free difference combination observations includes: Calculate the mean of the initial difference combination observations based on the initial difference combination observations; The target difference combination observation is obtained by subtracting the mean of the cycle-slip-free difference combination observation from the mean of the initial difference combination observation.

7. The antenna phase center calibration method as described in claim 1, characterized in that, Based on the target differential combination observations and the preset satellite, a phase center change model corresponding to the antenna under test is fitted, including: Based on the preset satellite, a dataset showing the relationship between the changes in satellite elevation angle and target difference combined observations is obtained through polynomial regression fitting. Based on the preset phase center change parameter set and the dataset of the relationship between the satellite elevation angle and the target differential combination observation value, a phase center change model corresponding to the antenna under test is fitted.

8. An antenna phase center calibration system, characterized in that, Performing an antenna phase center calibration method as described in any one of claims 1 to 7 includes: The system includes a data acquisition module, a first geometric distance-free combination observation acquisition module, a second geometric distance-free combination observation acquisition module, an initial difference combination observation acquisition module, a cycle slip-free difference combination observation acquisition module, a target difference combination observation acquisition module, a phase center change model construction module, and a phase center calibration module. The data acquisition module is used to observe a preset satellite through the antenna under test and the reference antenna, and to collect carrier phase observation data of the antenna under test and the carrier phase observation data of the reference antenna. The first geometric distance-free combined observation value acquisition module is used to calculate the frequency domain difference of the carrier phase observation data of the antenna under test, and obtain the geometric distance-free combined observation value of the antenna under test. The second geometric distance-free combined observation acquisition module is used to calculate the frequency domain difference of the reference antenna carrier phase observation data and construct the geometric distance-free combined observation of the reference antenna. The initial differential combination observation acquisition module is used to subtract the geometric distance-free combination observation value of the antenna under test at the corresponding frequency from the geometric distance-free combination observation value of the reference antenna to obtain the initial differential combination observation value. The cycle-slip-free differential combination observation acquisition module is used to obtain cycle-slip-free differential combination observations based on a preset cycle-slip threshold and the initial differential combination observations. The target difference combination observation acquisition module is used to construct target difference combination observations based on the cycle slip-free difference combination observations; The phase center change model construction module is used to fit the phase center change model corresponding to the antenna under test based on the target differential combination observation value and the preset satellite; The phase center calibration module is used to calibrate the phase center of the antenna under test based on the phase center change model.

9. An antenna phase center calibration terminal, characterized in that, The terminal includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements an antenna phase center calibration method as described in any one of claims 1 to 7.

10. A readable storage medium for antenna phase center calibration, characterized in that, The readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device containing the readable storage medium to perform an antenna phase center calibration method as described in any one of claims 1 to 7.

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