Measurement Method of Multi-station Propagation Delay Time-sharing Extension

Abstract

The present invention discloses a method for measuring the time-sharing extension of propagation delays of multiple stations, which is implemented according to the following steps: step 1, time-sharing tracking and measuring multiple stations to obtain propagation delay data of multiple stations with time information; step 2, pre-processing the propagation delay data of multiple stations obtained in step 1 to obtain the final intermittent propagation delay data of each station; step 3, according to the time information of step 1, the final intermittent propagation delay data of each station pre-processed in step 2 are extended for the whole period by using the segmented extension method to obtain the propagation delay data of each station that changes continuously with time. It effectively improves the measurement efficiency of long-wave ground wave propagation delay and reduces the measurement cost, can realize the simultaneous measurement of propagation delays of multiple stations, can realize the full-time extension of intermittent measurement data, and ensures that the measurement data can truly and reliably reflect the change of propagation delay with time.

Description

Technical Field

[0001] The invention belongs to the technical field of land-based long-wave navigation / timing, and in particular relates to a method for measuring time-division extension of propagation delays of multiple stations. Background Art

[0002] The land-based long-wave navigation / timing system is an important part of the modern PNT system, which uses long-wave ground wave signals as navigation / timing signals. In the process of realizing navigation and timing, obtaining accurate ground wave propagation delay at the receiving point is the key to ensuring high-precision navigation and timing. At the same time, long-term monitoring of the broadcast signal is also the key to ensuring the quality of the broadcast and mastering the time-varying law of the propagation delay. All of this requires a set of efficient long-wave ground wave propagation delay measurement methods.

[0003] The long-wave ground-wave propagation delay measurement system, which uses satellite timing time as the reference time, realizes the ground-wave propagation delay measurement by comparing the second signal output by the long-wave receiver with the second signal output by the high-precision timing GNSS (such as GPS, Beidou) receiver. Usually, the measurement of the broadcast signals of different stations is achieved by controlling the stations tracked by the long-wave receiver. The more measurement stations there are, the more receivers need to be configured or the more times the stations need to be switched; the more accurate the measurement results and the wider the measurement area, the longer the time required. In the measurement process, it is often expected to spend as little cost (including material, manpower, and time) as possible to obtain as many and accurate measurement results as possible (including obtaining the ground-wave propagation delays of as many broadcasting stations as possible, and the data can truly reflect the spatial and temporal variations of the propagation delay). Summary of the invention

[0004] The purpose of the present invention is to provide an efficient multi-station propagation delay time-sharing extension measurement method, a long-wave ground wave propagation delay measurement system using satellite timing time as the reference time, which can use a set of equipment to simultaneously measure the long-wave ground wave propagation delay of multiple stations through time-sharing measurement and data extension technology, thereby obtaining the propagation delay data of each station that changes continuously with time.

[0005] The technical solution adopted by the present invention is a method for measuring the time-division extension of propagation delay of multiple stations, which is specifically implemented according to the following steps:

[0006] Step 1: Time-sharing tracking and measuring of multiple stations to obtain multi-station propagation delay data with time information;

[0007] Step 2, preprocessing the propagation delay data of multiple stations obtained in step 1 to obtain the final intermittent propagation delay data of each station;

[0008] Step 3: Based on the time information of step 1 and the final intermittent propagation delay data of each station preprocessed in step 2, the final intermittent propagation delay data of each station is extended over the entire period using a segmented extension method to obtain the propagation delay data of each station that changes continuously over time.

[0009] The present invention is also characterized in that:

[0010] This measurement method is based on a long-wave ground wave propagation delay measurement system, which includes a long-wave receiver and a GNSS receiver. The long-wave receiver is connected to a long-wave receiver antenna, and the GNSS receiver is connected to a GNSS receiver antenna. Both the long-wave receiver and the GNSS receiver are connected to a time counter, and the long-wave receiver, the GNSS receiver, and the time counter are connected to a PC.

[0011] The long-wave receiver is connected to the long-wave receiver antenna. The long-wave receiver is used to provide basic information of each long-wave navigation / timing station and track the pulse group repetition period GRI signal of the timing station. The long-wave receiver sends the basic information of each long-wave navigation / timing station to the PC through the serial port, and outputs the GRI signal or the second (1PPS) signal to the time counter. The GNSS receiver is connected to the GNSS receiver antenna. The GNSS receiver is used to provide position information and the time reference 1PPS signal. The GNSS receiver sends the current position information to the PC through the serial port and sends the time reference 1PPS signal to the time counter. The GRI signal or 1PPS signal output by the long-wave receiver and the time reference 1PPS signal output by the GNSS receiver are compared by the time counter to obtain the propagation delay from the tracking station to the measurement point. The time counter sends the obtained propagation delay to the PC through the serial port.

[0012] Step 1 is as follows:

[0013] Set the time interval for switching tracking stations, and track and measure different stations at the time interval. The basis for selecting tracking stations is: the most expected measurement station or the station with good signal quality; time interval: switch the tracking station every 10 minutes; after comprehensively considering the tracking time and information integrity and conducting a large number of comparative tests, it is clear that the number of tracking stations should not exceed 3, and obtain multi-station propagation delay data with time information.

[0014] Step 2 is as follows:

[0015] Step 2.1: For the propagation delay data of multiple stations obtained in step 1, extract them separately according to different stations, and judge the data flag of the propagation delay data of multiple stations to determine whether the current data is normal and available. When the flag shows that the data is normal and available, extract the current data according to different stations; otherwise, discard the current data and obtain the initial intermittent propagation delay data of each station.

[0016] Step 2.2: For the initial intermittent propagation delay data of each station obtained in step 2.1, perform outlier judgment on each station.

[0017] Step 2.3: Correct the abnormal values ​​of the initial intermittent propagation delay data of the stations determined in step 2.2 to obtain the final intermittent propagation delay data of each station.

[0018] In step 2.2, the Raida criterion is used to judge outliers.

[0019] Step 2.3 is as follows:

[0020] For the abnormal values ​​in the initial intermittent propagation delay data of each station determined in step 2.2, in order to ensure the continuity of the propagation delay data sequence, they are replaced by the data of the previous point adjacent to the abnormal value to obtain the final intermittent propagation delay data of each station.

[0021] Step 3 is as follows:

[0022] Step 3.1: For the multi-station propagation delay data obtained in step 1, extract the time information according to different stations;

[0023] Step 3.2: Based on the time information of each station obtained in step 3.1 and the final intermittent propagation delay data of each station corrected in step 2, the final intermittent propagation delay data of each station is extended over the entire period according to different stations to obtain the propagation delay data of each station that changes continuously over time.

[0024] Step 3.2 is as follows:

[0025] Step 3.2.1, according to the time information of each station extracted in step 3.1, determine which half hour of each hour each ten-minute time is located according to different stations; and evenly expand the ten-minute time to the half hour according to different stations;

[0026] Step 3.2.2, the final intermittent propagation delay data of each station after preprocessing in step 2 is matched with the time after each station is evenly spread in step 3.2.1, and the final intermittent propagation delay data of each station is evenly spread in different time periods;

[0027] Step 3.2.3: For the time information of each station processed in step 3.2.1, the step length between each time point is constant, which is 3 seconds. Two new time points are evenly inserted between every two time points;

[0028] Step 3.2.4: For the time point inserted in step 3.2.3, based on the correspondence between the time information in step 3.2.2 and the final intermittent propagation delay data of each station, each station uses a cubic spline interpolation function to interpolate the propagation delay data at the inserted time point, thereby obtaining the propagation delay data of each station that changes continuously with time.

[0029] The multi-station propagation delay time-sharing extension measurement method of the present invention effectively improves the measurement efficiency of long-wave ground wave propagation delay and reduces the measurement cost. The time-sharing measurement method adopted can realize the simultaneous measurement of propagation delays of multiple stations; the segmented extension method adopted can realize the full-time extension of intermittent measurement data; the comprehensive consideration of the number of stations, interval time and extension method ensures that the measurement data can truly and reliably reflect the changes of propagation delay over time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of a long wave ground wave propagation delay measurement system of the present invention;

[0031] Figure 2 It is a schematic diagram of the process of the present invention;

[0032] Figure 3 This is the propagation delay diagram of the first station 6000M in a complete measurement of one day in an embodiment of the present invention;

[0033] Figure 4 This is a graph of intermittent propagation delay data obtained by time-sharing measurement of the first station 6000M in an embodiment of the present invention;

[0034] Figure 5 This is a data diagram of the propagation delay of the first station 6000M measured in time division after segment extension in an embodiment of the present invention;

[0035] Figure 6 This is the propagation delay diagram of the second station 8390M in a complete measurement of one day in an embodiment of the present invention;

[0036] Figure 7 This is a graph of intermittent propagation delay data obtained by time-sharing measurement of the second station 8390M in an embodiment of the present invention;

[0037] Figure 8 This is a data diagram of the propagation delay of the second station 8390M measured in time division after segment extension in an embodiment of the present invention;

[0038] Fig. 9 It is a propagation delay diagram of the third station 7430X of a complete measurement of one day in an embodiment of the present invention;

[0039] Fig.10This is a graph of intermittent propagation delay data obtained by time-sharing measurement of the third station 7430X in an embodiment of the present invention;

[0040] Fig.11 This is a data diagram of the propagation delay of the third station 7430X measured in time-sharing manner after segmented extension in an embodiment of the present invention.

[0041] In the figure, 1. long wave receiver antenna, 2. GNSS receiver antenna, 3. long wave receiver, 4. time counter, 5. GNSS receiver, 6. PC terminal. DETAILED DESCRIPTION

[0042] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] The measurement method of the present invention is based on the long wave ground wave propagation delay measurement system. Figure 1 As shown, it includes a long-wave receiver 3 and a GNSS receiver 5, the long-wave receiver 3 is connected to a long-wave receiver antenna 1, and the GNSS receiver 5 is connected to a GNSS receiver antenna 2; the long-wave receiver 3 and the GNSS receiver 5 are both connected to a time counter 4, and the long-wave receiver 3, the GNSS receiver 5, and the time counter 4 are connected to a PC terminal 6.

[0044] The selected long-wave receiver should have the following functions: it can receive the broadcast signals of different long-wave navigation / timing stations, it can track the signal of a long-wave navigation / timing station and output the GRI signal or the second signal, and the output signal does not correct the propagation delay. The selected high-precision timing GNSS receiver should have the following functions: it can receive multiple satellite signals (such as GPS, Beidou), it can locate the current position according to the received satellite signals and output the second signal.

[0045] In this embodiment, the structure of the long-wave ground wave propagation delay measurement system is as follows: the long-wave receiver 3 is connected to the long-wave receiver antenna 1, and the long-wave receiver 3 is used to provide basic information of each long-wave navigation / timing station, and simultaneously track the pulse group repetition period (GRI) signal of the timing station. The long-wave receiver 3 sends the basic information of each long-wave navigation / timing station to the PC6 terminal through the serial port, and outputs the GRI signal or the second (1PPS) signal to the time counter 4. The GNSS receiver 5 is connected to the GNSS receiver antenna 2, and the GNSS receiver 5 is used to provide position information and the time reference 1PPS signal. The GNSS receiver 5 sends the current position information to the PC6 terminal through the serial port, and sends the time reference 1PPS signal to the time counter 4. The GRI signal or 1PPS signal output by the long-wave receiver 3 and the time reference 1PPS signal output by the GNSS receiver 5 are compared by the time counter 4, and the propagation delay from the tracking station to the measurement point can be obtained. The time counter 4 sends the obtained propagation delay to the PC6 terminal through the serial port.

[0046] The present invention is a method for measuring the propagation delay of multiple stations by time division. The flow chart is as follows: Figure 2 As shown, the specific implementation steps are as follows:

[0047] Step 1: Time-sharing tracking and measuring of multiple stations to obtain multi-station propagation delay data with time information, as follows:

[0048] Set the time interval for switching tracking stations, and track and measure different stations at the time interval. The basis for selecting tracking stations is: the most expected measurement station or the station with good signal quality; time interval: switch the tracking station every 10 minutes; after comprehensively considering the tracking time and information integrity and conducting a large number of comparative tests, it is clear that the number of tracking stations should not exceed 3, and obtain the propagation delay data of multiple stations with time information.

[0049] In the embodiment of the present invention, 6000M, 8390M and 7430X long-wave transmitters are selected as tracking measurement stations to measure the propagation delays from the three transmitters to the XUT (Xi'an University of Technology, Xi'an University of Technology, referred to as "XUT") receiving point.

[0050] A 10-minute station-changing interval is set. At the 1st to 10th minute and the 31st to 40th minute of each hour, the propagation delay measurement system measures the propagation delay from the first station, the 6000M long-wave transmitter, to XUT. At the 11th to 20th minute and the 41st to 50th minute of each hour, the propagation delay measurement system measures the propagation delay from the second station, the 8390M long-wave transmitter, to XUT. At the 21st to 30th minute and the 51st to 60th minute of each hour, the propagation delay measurement system measures the propagation delay from the third station, the 7430X long-wave transmitter, to XUT, to obtain multi-station propagation delay data with time information.

[0051] Step 2: Preprocess the 6000M, 8390M and 7430X multi-station propagation delay data obtained in step 1. The specific steps are as follows:

[0052] Step 2.1: For the multi-station propagation delay data obtained in step 1, extract them according to different stations 6000M, 8390M and 7430X respectively. Perform data flag judgment on the propagation delay data of multiple stations to determine whether the current data is normal and available. When the flag is "q", it shows that the data is normal and available, and the current data is extracted according to different stations 6000M, 8390M and 7430X respectively; on the contrary, when the flag is not "q", the current data is discarded, and the initial intermittent propagation delay data of each station 6000M, 8390M and 7430X is obtained.

[0053] Step 2.2: For the initial intermittent propagation delay data of 6000M, 8390M and 7430X stations obtained in step 2.1, perform outlier judgment according to different stations;

[0054] Step 2.3: Correct the abnormal values ​​of the initial intermittent propagation delay data of 6000M, 8390M and 7430X stations determined in step 2.2 to obtain the final intermittent propagation delay data of each station. In the actual measured propagation delay data, if a set of measured data contains abnormal values ​​and is not eliminated, it will directly affect the further analysis of the later data. In order to minimize the impact on the further analysis of the later data, it is necessary to correct the abnormal values ​​in the propagation delay data.

[0055] In step 2.2, the Raida criterion is used to judge outliers.

[0056] Step 2.3 is as follows:

[0057] For the abnormal values ​​in the initial intermittent propagation delay data of 6000M, 8390M and 7430X stations determined in step 2.2, in order to meet the continuity of the propagation delay data sequence, they are replaced by the data of the previous point adjacent to the abnormal value: for the abnormal value in the initial intermittent propagation delay data of the first station 6000M long-wave transmitter to XUT, it is replaced by the data of the previous point adjacent to the abnormal value of the initial intermittent propagation delay data of the 6000M long-wave transmitter to XUT, and the final intermittent propagation delay data of the first station 6000M is obtained; for the second station 8390 The outliers in the initial intermittent propagation delay data from the M long-wave transmitter to XUT are replaced by the data of the previous point adjacent to the outliers in the initial intermittent propagation delay data from the 8390M long-wave transmitter to XUT, and the final intermittent propagation delay data of the second station 8390M are obtained; for the outliers in the initial intermittent propagation delay data from the 7430X long-wave transmitter to XUT of the third station, the data of the previous point adjacent to the outliers in the initial intermittent propagation delay data from the 7430X long-wave transmitter to XUT are replaced by the data of the previous point adjacent to the outliers in the initial intermittent propagation delay data from the 7430X long-wave transmitter to XUT, and the final intermittent propagation delay data of the third station 7430X are obtained.

[0058] Step 3: Based on the time information of step 1 and the final intermittent propagation delay data of each station preprocessed in step 2, the final intermittent propagation delay data of each station is extended over the entire period using the segmented extension method to obtain the propagation delay data of each station that changes continuously over time, as follows:

[0059] Step 3.1, for the multi-station propagation delay data obtained in step 1, extract the time information according to different stations 6000M, 8390M and 7430X;

[0060] Step 3.2: According to the time information of each station 6000M, 8390M and 7430X obtained in step 3.1 and the final intermittent propagation delay data of each station 6000M, 8390M and 7430X corrected in step 2, the final intermittent propagation delay data of each station is extended for the whole period according to different stations to obtain the propagation delay data of each station that changes continuously with time:

[0061] According to the time information of the first station 6000M obtained in step 3.1 and the final intermittent propagation delay data of the first station 6000M corrected in step 2, the final intermittent propagation delay data of the first station 6000M is extended for the entire period; according to the time information of the second station 8390M obtained in step 3.1 and the final intermittent propagation delay data of the second station 8390M corrected in step 2, the final intermittent propagation delay data of the second station 8390M is extended for the entire period; according to the time information of the third station 7430X obtained in step 3.1 and the final intermittent propagation delay data of the third station 7430X corrected in step 2, the final intermittent propagation delay data of the third station 7430X is extended for the entire period.

[0062] Step 3.2 is as follows:

[0063] Step 3.2.1: Based on the time information of each station extracted in step 3.1, determine which half hour of each hour each ten minutes of time is located according to different stations; and evenly expand the ten minutes of time to the half hour of each hour according to different stations.

[0064] For the first station 6000M, when the time is between the 1st and 10th minutes of each hour, it is in the first half hour of each hour; when the time is between the 31st and 40th minutes of each hour, it is in the second half hour of each hour. Evenly expand every ten minutes of the first station 6000M to the corresponding half hour: evenly expand the time between the 1st and 10th minutes of each hour to the first half hour of the hour; evenly expand the time between the 31st and 40th minutes of each hour to the second half hour of the hour, as the evenly expanded time T of the first station 6000M r1 :

[0065]

[0066] Where, T p1 is the unprocessed time of the first station 6000M, in hours, It is the integer part of the unprocessed time of the first station 6000M.

[0067] For the second station 8390M, when the time is between the 11th and 20th minutes of each hour, it is in the first half hour of each hour; when the time is between the 41st and 50th minutes of each hour, it is in the second half hour of each hour. Evenly expand every ten minutes of the second station 8390M to the corresponding half hour: evenly expand the time between the 11th and 20th minutes of each hour to the first half hour of the hour; evenly expand the time between the 41st and 50th minutes of each hour to the second half hour of the hour, as the time T after the second station 8390M is evenly expanded. r2 :

[0068]

[0069] Where, T p2 is the unprocessed time of the second station 8390M, in hours, It is the integer part of the unprocessed time of the second station 8390M.

[0070] For the third station 7430X, when the time is between the 21st and 30th minutes of each hour, it is in the first half hour of each hour; when the time is between the 51st and 60th minutes of each hour, it is in the second half hour of each hour. Evenly expand every ten minutes of the third station 7430X to the corresponding half hour: evenly expand the time between the 21st and 30th minutes of each hour to the first half hour of the hour; evenly expand the time between the 51st and 60th minutes of each hour to the second half hour of the hour, as the time T after the third station 7430X is evenly expanded in sections r3 :

[0071]

[0072] Where, T p3 is the unprocessed time of the third station 7430X, in hours, It is the integer part of the unprocessed time of the third station 7430X.

[0073] Step 3.2.2: The final intermittent propagation delay data of each station after preprocessing in step 2 is matched with the time after each station is evenly expanded in step 3.2.1. The final intermittent propagation delay data of each station is evenly expanded in different time periods:

[0074] The final intermittent propagation delay data of the first station 6000M after preprocessing in step 2 is corresponded one by one with the time after the uniform expansion of the first station 6000M in step 3.2.1, and the final intermittent propagation delay data of the first station 6000M is evenly expanded in different time periods; the final intermittent propagation delay data of the second station 8390M after preprocessing in step 2 is corresponded one by one with the time after the uniform expansion of the second station 8390M in step 3.2.1, and the final intermittent propagation delay data of the second station 8390M is evenly expanded in different time periods; the final intermittent propagation delay data of the third station 7430X after preprocessing in step 2 is corresponded one by one with the time after the uniform expansion of the third station 7430X in step 3.2.1, and the final intermittent propagation delay data of the third station 7430X is evenly expanded in different time periods.

[0075] Step 3.2.3: For the time information of each station processed in step 3.2.1, the step length between each time point is constant, which is 3 seconds. Two new time points are evenly inserted between every two time points:

[0076] For the time information of the first station 6000M, the interval between every two time points is 3 seconds, and two new time points are evenly inserted; for the time information of the second station 8390M, the interval between every two time points is 3 seconds, and two new time points are evenly inserted; for the time information of the third station 7430X, the interval between every two time points is 3 seconds, and two new time points are evenly inserted.

[0077] Step 3.2.4: For the time point inserted in step 3.2.3, according to the corresponding relationship between the time information in step 3.2.2 and the final intermittent propagation delay data of each station, each station uses a cubic spline interpolation function to interpolate the propagation delay data at the inserted time point, thereby obtaining the propagation delay data of each station that changes continuously with time:

[0078] For the time point when the first station 6000M is inserted in step 3.2.3, based on the corresponding relationship between the time information of the first station 6000M in step 3.2.2 and the final intermittent propagation delay data of the first station 6000M, the cubic spline interpolation function is used to interpolate the propagation delay data at the time point when the first station 6000M is inserted, thereby obtaining the propagation delay data of the first station 6000M that continuously changes with time; for the time point when the second station 8390M is inserted in step 3.2.3, based on the time information of the second station 8390M in step 3.2.2 and the final intermittent propagation delay data of the second station 8390M According to the correspondence between the time information of the third station 7430X in step 3.2.2 and the final intermittent propagation delay data of the third station 7430X, the cubic spline interpolation function is used to interpolate the propagation delay data at the time point of the insertion of the second station 8390M, thereby obtaining the propagation delay data of the second station 8390M that changes continuously with time; for the time point of the insertion of the third station 7430X in step 3.2.3, according to the correspondence between the time information of the third station 7430X in step 3.2.2 and the final intermittent propagation delay data of the third station 7430X, the cubic spline interpolation function is used to interpolate the propagation delay data at the time point of the insertion of the third station 7430X, thereby obtaining the propagation delay data of the third station 7430X that changes continuously with time.

[0079] Figure 3 The propagation delay diagram of the first station 6000M in the complete measurement of one day in this embodiment is given, and the mean and standard deviation are marked in the figure, and their values ​​are 307.9676μs and 0.0125μs respectively; Figure 4 This is a diagram of intermittent propagation delay data of the first station 6000M measured in time division in an embodiment of the present invention; Figure 5 The data graph of the propagation delay of the first station 6000M measured in time-sharing mode after segment extension in this embodiment is given, and the mean value and standard deviation are marked in the graph, and their values ​​are 307.9676μs and 0.0125μs respectively;

[0080] Depend on Figure 3 and Figure 5 It can be seen that the change pattern of the data after the segmented extension of the time-sharing measurement of the propagation delay of 6000M at the first station is similar to the change pattern of the propagation delay of 6000M in a complete measurement of one day. The extended data can truly and reliably reflect the change of the 6000M propagation delay over time.

[0081] Figure 6 The propagation delay diagram of the second station 8390M in a complete measurement of one day in this embodiment is given, and the mean and standard deviation are marked in the figure, and their values ​​are 3319.6687μs and 0.1245μs respectively; Figure 7 This is a graph of intermittent propagation delay data of the second station 8390M measured in time division in an embodiment of the present invention; Figure 8The data graph of the propagation delay of the second station 8390M measured in time-sharing mode after segment extension in this embodiment is given, and the mean value and standard deviation are marked in the graph, and their values ​​are 3319.6688μs and 0.1219μs respectively;

[0082] Depend on Figure 6 and Figure 8 It can be seen that the change pattern of the propagation delay of the second station 8390M after the segmented extension of the time-sharing measurement is similar to the change pattern of the propagation delay of 8390M measured in one day. The extended data can truly and reliably reflect the change of the propagation delay of 8390M over time.

[0083] Fig. 9 The propagation delay diagram of the third station 7430X in a complete measurement of one day in this embodiment is given, and the mean and standard deviation are marked in the figure, and their values ​​are 3318.8777μs and 0.1192μs respectively; Fig.10 This is a graph of intermittent propagation delay data of the third station 7430X measured in time division in an embodiment of the present invention; Fig.11 The data graph of the propagation delay of the third station 7430X measured in time-sharing mode after segment extension in this embodiment is given, and the mean value and standard deviation are marked in the graph, and their values ​​are 3318.8788μs and 0.1192μs respectively;

[0084] Depend on Fig. 9 and Fig.11 It can be seen that the change pattern of the propagation delay of the third station 7430X measured in time-sharing mode after segmented extension is similar to the change pattern of the propagation delay of 7430X measured in one day. The extended data can truly and reliably reflect the change of the propagation delay of 7430X over time.

[0085] Based on the above analysis, the long-wave ground wave propagation delay measurement system adopts a time-sharing measurement method, which can realize the simultaneous measurement of propagation delays of multiple stations; the segmented extension method can realize the full-time extension of intermittent measurement data. The extended data can truly and reliably reflect the changes of propagation delay over time.

Claims

1. A method for measuring multi-station propagation delay by time division, characterized in that: Follow the steps below to implement it: Step 1: Time-sharing tracking and measuring of multiple stations to obtain multi-station propagation delay data with time information; In the step 1, different stations are tracked and measured at intervals of 10 minutes to obtain propagation delay data of multiple stations with time information; Step 2, preprocessing the propagation delay data of multiple stations obtained in step 1 to obtain the final intermittent propagation delay data of each station; The step 2 is specifically implemented according to the following steps: Step 2.1, extract the propagation delay data of multiple stations obtained in step 1 according to different stations, perform data flag bit judgment on the propagation delay data of multiple stations, and judge whether the current data is normal and available; When the flag indicates that the data is available normally, the current data is extracted according to different stations; otherwise, the current data is discarded and the initial intermittent propagation delay data of each station is obtained; Step 2.2: For the initial intermittent propagation delay data of each station obtained in step 2.1, perform outlier judgment on each station; Step 2.3, correcting the abnormal values ​​of the initial intermittent propagation delay data of the stations determined in step 2.2, and obtaining the final intermittent propagation delay data of each station; Step 3: Based on the time information of step 1 and the final intermittent propagation delay data of each station preprocessed in step 2, a segmented extension method is used to extend the final intermittent propagation delay data of each station over the entire period of time to obtain the propagation delay data of each station that continuously changes with time; The step 3 is specifically implemented according to the following steps: Step 3.1: For the multi-station propagation delay data obtained in step 1, extract the time information according to different stations; Step 3.2, according to the time information of each station obtained in step 3.1 and the final intermittent propagation delay data of each station corrected in step 2, the final intermittent propagation delay data of each station is extended for the entire period according to different stations to obtain the propagation delay data of each station that changes continuously with time; The step 3.2 is specifically implemented according to the following steps: Step 3.2.1, according to the time information of each station extracted in step 3.1, determine which half hour of each hour each ten-minute time is located according to different stations; and evenly expand the ten-minute time to the half hour according to different stations; Step 3.2.2, the final intermittent propagation delay data of each station after preprocessing in step 2 is matched with the time after each station is evenly spread in step 3.2.1, and the final intermittent propagation delay data of each station is evenly spread in different time periods; Step 3.2.3: For the time information of each station processed in step 3.2.1, the step length between any two time points is constant, which is 3 seconds. Two new time points are evenly inserted between every two time points. Step 3.2.4: For the time point inserted in step 3.2.3, based on the correspondence between the time information in step 3.2.2 and the final intermittent propagation delay data of each station, each station uses a cubic spline interpolation function to interpolate the propagation delay data at the inserted time point, thereby obtaining the propagation delay data of each station that changes continuously with time.

2. The method for measuring the time-division extension of propagation delay of multiple stations according to claim 1, characterized in that: The number of tracking stations in step 1 shall not exceed 3.

3. The method for measuring the time-division extension of propagation delay of multiple stations according to claim 1, characterized in that: In step 2.2, the Raida criterion is used to determine outliers.

4. The method for measuring the time-division extension of propagation delay of multiple stations according to claim 1, characterized in that: Step 2.3 is specifically implemented according to the following steps: For the abnormal values ​​in the initial intermittent propagation delay data of each station determined in step 2.2, in order to meet the continuity of the propagation delay data sequence, the data of the previous point adjacent to the abnormal value are used to replace them respectively to obtain the final intermittent propagation delay data of each station.

5. The method for measuring the time-division extension of propagation delay of multiple stations according to claim 4, characterized in that: The method is completed based on a long-wave ground wave propagation delay measurement system, wherein the long-wave ground wave propagation delay measurement system comprises a long-wave receiver (3) and a GNSS receiver (5), wherein the long-wave receiver (3) is connected to a long-wave receiver antenna (1), and the GNSS receiver (5) is connected to a GNSS receiver antenna (2); the long-wave receiver (3) and the GNSS receiver (5) are both connected to a time counter (4), and the long-wave receiver (3), the GNSS receiver (5), and the time counter (4) are connected to a PC end (6).

Images