CN112636893B - Method for improving eLoran system time service precision by using ASF grid and differential station - Google Patents
Method for improving eLoran system time service precision by using ASF grid and differential station Download PDFInfo
- Publication number
- CN112636893B CN112636893B CN202011365905.0A CN202011365905A CN112636893B CN 112636893 B CN112636893 B CN 112636893B CN 202011365905 A CN202011365905 A CN 202011365905A CN 112636893 B CN112636893 B CN 112636893B
- Authority
- CN
- China
- Prior art keywords
- asf
- time
- spacial
- grid
- eloran
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/0016—Arrangements for synchronising receiver with transmitter correction of synchronization errors
- H04L7/002—Arrangements for synchronising receiver with transmitter correction of synchronization errors correction by interpolation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/06—Synchronising arrangements
- H04J3/0635—Clock or time synchronisation in a network
- H04J3/0682—Clock or time synchronisation in a network by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
Abstract
The invention provides a method for improving the time service precision of an eLoran system by utilizing an ASF grid and a differential station, wherein the differential station carries out real-time difference measurement and calculates a differential correction number model to be transmitted to peripheral users; establishing an ASF grid database by using dynamic measurement data and an inverse bilinear interpolation algorithm; the user calculates the time delay of the user, and calculates the difference correction number according to the difference information to obtain the time component of the ASF; then, searching the located grid, and calculating the space component of the ASF according to the position information and the ASF values of the four vertexes of the grid; and finally, correcting the signal propagation delay by using the time component and the space component together to obtain more accurate signal propagation delay, thereby improving the time service precision of the system.
Description
Technical Field
The invention belongs to the technical field of communication, and relates to a time service method.
Background
With the deep and wide application of the GNSS system, the vulnerability of the GNSS system is gradually exposed, and the eLoran system is selected as a backup system of the GNSS system by virtue of the advantages of good signal stability, high reliability, strong anti-interference performance, long propagation distance and the like; however, the eLoran system and the GNSS system have a certain gap in terms of accuracy. Expert scholars in various countries begin to study methods for improving the precision of the eLoran system. The ASF grid improves eLoran precision from spatial dimension, and can realize time service precision superior to 200 ns; the time service precision of the eLoran system is improved by the time dimension of the differential station, and is close to 100 ns. The differential station significantly improves the accuracy of the eLoran system, but has some gap with the GNSS system. How to further improve the precision of the eLoran system and narrow the gap between the precision of the eLoran system and the precision of the GNSS system is an urgent problem to be solved.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a method for improving the precision of an eLoran system by comprehensively applying an ASF grid and a differential station.
The technical scheme adopted by the invention for solving the technical problem comprises the following steps:
(1) calculating the large ground wire distance of signal propagation according to the antenna position of the eLoran reference receiver and the transmitting antenna position of the transmitting station, and then calculating the signal propagation one-time delay PF;
(2) measuring and collecting the time difference N between a 1PPS signal output by an eLoran reference receiver and a standard time-frequency signal by using the standard time-frequency signal;
(3) using time difference data N acquired within a set duration i The PF is deducted to obtain an additional secondary time delay value ASF of the differential station at the ith moment i Forecasting the difference correction number model y ═ a in the set time by using least square fitting 1 t+a 0 Model coefficient a of 1 、a 0 Y represents ASF, t represents time and is sent to the surrounding users;
(4) in an arbitrarily set area, measuring the ASF (acquired Signal propagation time delay) according to an arbitrarily set track spacial ；
(5) If there are k test points in a grid, k spatial components ASF are measured spacial (ii) a ASF using these k test points spacial_j ASF of value-backprojection mesh vertices spacial ；
(6) Calculate each vertex ASF spacial After the value, according to the format [ Long j ,Lati j ,ASF spacial_j ]Stored into ASF grid database, wherein Long j 、Lati j 、ASF spacial_j Respectively representing longitude, latitude and ASF values of the grid vertex;
(7) the user calculates the large ground distance of signal propagation according to the antenna position of eLoran receiver and the transmitting antenna position of the transmitting station, and then calculates the one-time delay PF of signal propagation User' s ；
(8) Calculating ASF time component ASF using difference correction number model temperal Correcting the propagation delay TOA from the time dimension to PF User' s +ASF temperal ；
(9) Calculating ASF space component by using bilinear interpolation algorithm, and correcting signal propagation delay TOA (time of arrival) ═ PF + ASF from space dimension temperal +ASF sapcial 。
The step (1) calculates the time delay of signal propagation
Wherein n is s Representing the atmospheric refractive index, C the speed of light, d the distance of the large ground from the launch pad to the test point signal propagation.
The step (4) takes 1PPS output by the GPS receiver or the GNSS receiver or the BD receiver as a reference standard, and compares the reference standard with the time difference M of 1PPS output by the eLoran reference receiver by using a time interval counter i Obtaining ASF 'of the test point' i ＝M i PF', and then deducting the ASF of the differential station at the same moment i Obtaining space component ASF of test point relative to differential station spacial ＝ASF' i -ASF i 。
The step (5) establishes a matrix equation according to a bilinear interpolation algorithm, wherein C1, C2, C3 and C4 represent ASF of grid vertices spacial ，
ASF for obtaining grid vertex by solving matrix equation spacial Values, wherein the coefficient matrix
Assuming that there are (m-1) × n meshes in one region and there are m × n corresponding mesh vertices, the mesh vertices are arranged to obtain C ═ C [ -n [ -C ] ] 1 ,C 2 …C n ,C n+1 ,C n+2 …C 2n ,C (m-1)*n+1 ,C (m-1)*n+2 …C m*n ]', equation of the ith test point
(1-α i )·(1-β i )·C 2 +(1-α i )·β i ·C 3 +α i ·(1-β i )·C n+2 +α i ·β i ·C n+3 ＝ASF spacial_i The matrix equation is A x C ═ ASF spacial_i Solving the matrix equation to obtain C, i.e. ASF of the grid vertex spacial The value is obtained.
In the step (9), the coordinates of the user are (x, y), and the coordinates of four vertexes of the grid are (x, y) respectively 1 ,y 1 )、 (x 2 ,y 2 )、(x 3 ,y 3 ) And (x) 4 ,y 4 ) Four-point ASF spacial ASF with values of C1, C2, C3 and C4, respectively, at the point to be interpolated (x, y) sapcial ＝(1-α)[(1-β)*C1+β*C3]+α[[(1-β)*C2+β*C4]]Wherein
The invention has the beneficial effects that: the method comprehensively utilizes the advantages of the ASF grid and the differential station technology, corrects the propagation delay of the signal from the space dimension and the time dimension, breaks through the limitation that the grid only corrects the propagation delay from the space dimension, breaks through the limitation that the differential station only corrects the propagation delay from the time dimension, and improves the time service precision of the eLoran system from 100ns to 50ns when only the differential station acts.
Compared with the traditional ASF grid establishing method, the ASF grid establishing method adopts the inverse operation of dynamic testing and bilinear interpolation algorithm and is based on the space component ASF of the test point relative to the differential station spacial And the space component is convenient for a user to correct. Thus, instead of the ASF of the mesh vertices, the mesh database storesVertex ASF versus differential station spatial component ASF spacial 。
Drawings
FIG. 1 is a layout of a grid;
FIG. 2 is a schematic diagram of a grid;
FIG. 3 is a flow chart;
FIG. 4 is a dynamic test trace.
Detailed Description
The present invention will be further described with reference to the following drawings and examples, which include, but are not limited to, the following examples.
The invention provides an ASF (enhanced secondary factor) grid of an eLoran (enhanced Long Range navigation) system established by utilizing inverse operation of a bilinear interpolation algorithm, and a user corrects propagation delay of received signals from time and space latitude by utilizing the combined action of the ASF grid and differential information of a differential station, so that the time service precision of the eLoran system is improved.
The idea of the invention is as follows: the differential station must have a standard time-frequency signal, real-time difference measurement is carried out, and a differential correction number model is calculated and transmitted to peripheral users; firstly, an ASF grid database is established by utilizing dynamic measurement data and an inverse bilinear interpolation algorithm. Firstly, a user calculates the time delay of the user, and calculates a difference correction number according to difference information to obtain an ASF time component; then, searching the located grid, and calculating the space component of the ASF according to the position information and the ASF values of four vertexes of the grid; and finally, correcting the signal propagation delay by using the time component and the space component together to obtain more accurate signal propagation delay, thereby improving the time service precision of the system.
The technical scheme of the invention comprises the following steps:
(1) the differential station calculates one-time delay PF according to the position information
And calculating the large ground distance of signal propagation according to the antenna position of the eLoran reference receiver and the transmitting antenna position of the transmitting station, and then calculating the signal propagation one-time delay PF according to a formula (1-1).
Wherein n is s Indicating the refractive index of the atmosphere, international standard atmospheric regulation n s 1.000315, the speed of light C is 0.299792458 km/mus, and d is the distance from the broadcaster to the ground line where the test point signal travels.
(2) Differential station test acquisition data
And measuring and acquiring the time difference N between the 1PPS signal output by the eLoran reference receiver and the standard time frequency signal by using the standard time frequency signal, and acquiring one datum per second.
(3) Model for calculating difference correction
PF was subtracted from N using 600 data N collected over 10 minutes i I is more than or equal to 1 and less than or equal to 600, and subtracting PF to obtain ASF value ASF of the differential station at the ith moment i ＝N i PF (added secondary delay factor), forecasting a difference correction model within 5 minutes by using least square fitting (modeling the ASF value of the current 10 minutes of the difference station by using least square fitting, and y is a 1 t+a 0 Y denotes ASF, t denotes time) y ═ a 1 t+a 0 Model coefficient a of 1 、 a 0 And sending the data to peripheral users (the distance between the user and the differential station is not more than 55 km).
(4) Testing collected data
In an arbitrarily set area, the propagation delay of the acquired signal is measured according to an arbitrarily set track, and in the specific process, 1PPS output by a GPS receiver (or a GNSS receiver or a BD receiver) is taken as a reference standard, and a time interval counter is used for comparing the time difference M of the 1PPS output by the GPS and the 1PPS output by an eLoran reference receiver. M i Subtracting the one-time delay PF ' of the test point to obtain ASF ' of the test point ' i ＝M i PF', and then deducting the ASF of the differential station at the same moment i Obtaining space component ASF of test point relative to differential station spacial ＝ASF' i -ASF i . The calculation formula of the first time delay PF is shown as 1-1, and ASF spacial The calculation of (a) is shown in equations 1-2.
ASF spacial ＝ASF' i -ASF i (1-2)
(5) ASF value calculation by inverse bilinear interpolation algorithm
If there are k test points in a grid, k spatial components ASF are measured spacial (ii) a ASF using these k test points spacial_j ASF of value-backprojection mesh vertices spacial . Firstly, an equation set is established according to a bilinear interpolation algorithm as shown in (1-3), wherein C1, C2, C3 and C4 represent ASF of grid vertices spacial 。
It is converted into a matrix equation as shown in (1-4) below
ASF for obtaining grid vertex by solving matrix equation spacial Values, as shown in 1-5.
Coefficient matrix
Assuming that there are (m-1) × n meshes in one region and there are m × n corresponding mesh vertices, as shown in fig. 1, the dotted line in the figure is a test trace, and the mesh vertices are first arranged as shown in formulas 1 to 6.
C＝[C 1 ,C 2 …C n ,C n+1 ,C n+2 …C 2n ,C (m-1)*n+1 ,C (m-1)*n+2 …C m*n ]' (1-6)
The equation of the ith test point is shown in formulas 1-6
(1-α i )·(1-β i )·C 2 +(1-α i )·β i ·C 3 +α i ·(1-β i )·C n+2 +α i ·β i ·C n+3 ＝ASF spacial_i (1-7)
The matrix equation is shown in (1-7)
A*C＝ASF spacial_i (1-8)
Solving the matrix equation to obtain C, i.e. ASF of the mesh vertex spacial The value is obtained.
(6) Building a grid database
Calculate each vertex ASF spacial After the value, according to the format [ Long j ,Lati j ,ASF spacial_j ](longitude, latitude and ASF of grid vertex) is stored in ASF grid database, which is convenient for user to query and use.
(7) The user calculates a time delay PF according to the position information
Calculating the large ground wire distance of signal propagation according to the antenna position of eLoran receiver and the transmitting antenna position of transmitting station, and then calculating the one-time signal propagation delay PF according to the formula (1-1) User' s 。
(8) Calculating ASF time component ASF using difference correction number model temperal Correcting propagation delay from the time dimension
TOA＝PF User' s +ASF temperal (1-9)
(9) Calculating ASF space component by using bilinear interpolation algorithm, and correcting propagation delay from space dimension
According to the coordinates (x, y) of the self-body and the coordinates (x) of four vertexes of the located grid 1 ,y 1 )、(x 2 ,y 2 )、(x 3 ,y 3 ) And (x) 4 ,y 4 ) Computing ASF using bilinear interpolation algorithm spacial The value is obtained. As shown in FIG. 2, assuming A, B, C and D coordinates of four points as shown, the four points ASF spacial ASF with values of C1, C2, C3 and C4, respectively, at the point (x, y) to be interpolated spacial Has a value of
ASF sapcial ＝(1-α)[(1-β)*C1+β*C3]+α[[(1-β)*C2+β*C4]]， (1-10)
Wherein
Correcting signal propagation delay from spatial dimensions
TOA＝PF+ASF temperal +ASF sapcial (1-11)
The following examples are given by taking a grid as an example, and experiments were carried out using eLoran broadcasting station (Typha) of national time service center of Chinese academy of sciences, the location of the broadcasting station (109.5431, 34.9486).
The differential station performs the following operations:
(1) calculating a time delay PF from position information
The specific position (106.5, 34.8) of the differential receiver antenna placed by the differential station calculates the geodesic distance 278.6985km of signal propagation according to the antenna position of the eLoran reference receiver and the transmitting antenna position of the broadcasting station, and then calculates the signal propagation time delay PF 92.9310 mus according to the formula (1-1).
(2) Testing collected data
And measuring and acquiring the time difference N between the 1PPS signal output by the eLoran reference receiver and the standard time-frequency signal by using the standard time-frequency signal, and acquiring one datum every second.
(3) Model for calculating difference correction
According to the collected data, the difference correction model in a certain time period is y ═ a 1 t+a 0 Wherein t is the data age of the forecasting model, t is more than or equal to 0 and less than or equal to 300s, the data age is 5 minutes, a 1 ＝0.0016,a 0 ＝0.0784。
The establishment of the ASF mesh comprises the following operations:
(1) testing collected data
Data are acquired by using a test acquisition system, and 5 test points are taken from the test track in fig. 4 and are sequentially marked as P1, P2, P3, P4 and P5 from left to right. The secondary delay ASF of the differential station is measured to be 1.4860 mus, the coordinates of the 5 points and the measured ASF and the spatial component relative to the differential station are the ASF sapcial As shown in the table below.
Table 1 test point location information and ASF spatial components relative to a differential station
| Test point | Longitude (G) | Latitude | Distance between two adjacent plates | ASF/μs | ASF sapcial /μs |
| P1 | 106.22 | 35.24 | 304.7239 | 1.5881 | 0.1021 |
| P2 | 106.24 | 35.26 | 303.1402 | 1.5819 | 0.0959 |
| P3 | 106.26 | 35.26 | 301.3090 | 1.5747 | 0.0887 |
| P4 | 106.28 | 35.26 | 299.4980 | 1.5676 | 0.0816 |
| P5 | 106.28 | 35.24 | 299.2811 | 1.5668 | 0.0808 |
(2) Computing ASF space component value by inverse bilinear interpolation algorithm
The set of equations is set up as follows,
let coefficient matrix A
(3) Building a grid database
TABLE 2 mesh vertex ASF spatial component database
| Mesh vertices | Longitude (G) | Latitude | ASF sapcial /μs |
| C1 | 106 | 35 | 0.1072 |
| C2 | 106.2 | 35 | 0.0722 |
| C3 | 106 | 35.2 | 0.1122 |
| C4 | 106.2 | 35.2 | 0.0759 |
The user performs the following operations:
(1) calculating a time delay PF from position information
The antenna position (106.1, 35.1) of the user receiver calculates the geodesic distance 314.6520km of signal propagation according to the antenna position of the eLoran receiver and the transmitting antenna position of the transmitting station, and then calculates the time delay PF of signal propagation once according to the formula (1-1) User' s ＝1049.8907μs。
(2) Computing ASF time component ASF using difference model and model parameters temperal 0.1256 mus, the propagation delay TOA is corrected from the time dimension by PF User' s +ASF temperal ＝1050.0163μs
(3) Calculating an ASF space component 0.0919 mu s by using a bilinear interpolation algorithm, and correcting the propagation delay TOA (time of arrival) from the space dimension to be PF User' s +ASF temperal +ASF spacial ＝1050.1082μs
The measured actual path delay is 1050.1405 mus, the delay corrected by the differencing station and the trellis is 1050.1082 mus, and the difference is 32 ns. Therefore, the time service error of eLoran after comprehensive correction of the differential station and the ASF grid is better than 50 ns.
Claims (4)
1. A method for improving the time service precision of an eLoran system by using an ASF grid and a differential station is characterized by comprising the following steps:
(1) the differential station calculates the large ground wire distance of signal propagation according to the antenna position of the eLoran reference receiver and the transmitting antenna position of the transmitting station, and then calculates the signal propagation one-time delay PF;
(2) the differential station measures and collects the time difference N of a 1PPS signal output by the eLoran reference receiver and a standard time-frequency signal by using the standard time-frequency signal;
(3) the difference station utilizes the time difference data N acquired in the set time length i The PF is deducted to obtain an additional secondary time delay value ASF of the differential station at the ith moment i Forecasting the difference correction number model y ═ a in the set time by using least square fitting 1 t+a 0 Model coefficient a of 1 、a 0 Y represents ASF, t represents time and is sent to the surrounding users;
(4) in an arbitrarily set area, measuring the ASF (acquired Signal propagation time delay) according to an arbitrarily set track spacial ；
(5) If there are k test points in a grid, k spatial components ASF are measured spacial (ii) a ASF using these k test points spacial_j ASF of value-backprojection mesh vertices spacial ；
(6) Calculate each vertex ASF spacial After the value, according to the format [ Long j ,Lati j ,ASF spacial_j ]Stored into ASF grid database, wherein Long j 、Lati j 、ASF spacial_j Respectively representing longitude, latitude and ASF values of the grid vertex;
(7) the user calculates the large ground wire distance of signal propagation according to the antenna position of eLoran reference receiver and the transmitting antenna position of the transmitting station, and then calculates the signal propagation one-time delay PF User' s ；
(8) User calculates ASF time component ASF by using difference correction number model temperal Correcting the propagation delay TOA from the time dimension to PF User' s +ASF temperal ；
(9) The user calculates ASF space components by using a bilinear interpolation algorithm, and corrects the signal propagation delay TOA (time of arrival) from the dimension of the space to be PF + ASF temperal +ASF sapcial ；
In the step (9), the coordinates of the user are (x, y), and the coordinates of four vertexes of the grid are (x, y) respectively 1 ,y 1 )、(x 2 ,y 2 )、(x 3 ,y 3 ) And (x) 4 ,y 4 ) Four-point ASF spacial ASF with values of C1, C2, C3 and C4, respectively, at the point (x, y) to be interpolated sapcial ＝(1-α)[(1-β)*C1+β*C3]+α[[(1-β)*C2+β*C4]]Wherein
2. The method for improving the time service accuracy of eLoran system by using ASF grids and difference stations as claimed in claim 1, wherein said step (1) calculates the time delay of signal propagation
Wherein n is s Representing the atmospheric refractive index, C the speed of light, d the distance of the large ground from the launch pad to the test point signal propagation.
3. The method for improving the timing accuracy of eLoran system using ASF grid and difference station as claimed in claim 1, wherein said step (4) is performed by using 1PPS outputted from GPS receiver or GNSS receiver or BD receiver as reference standard, and comparing the time difference M of the reference standard and 1PPS outputted from eLoran reference receiver by using time interval counter i Obtaining ASF 'of the test point' i ＝M i PF', and then deducting the ASF of the differential station at the same moment i Obtaining space component ASF of test point relative to differential station spacial ＝ASF′ i -ASF i 。
4. The method for improving the timing accuracy of eLoran system using ASF grids and differencing stations as claimed in claim 1, wherein said step (5) establishes matrix equations according to bilinear interpolation algorithm, wherein C1, C2, C3 and C4 represent ASF of grid vertices spacial ，
ASF for obtaining grid vertex by solving matrix equation spacial Values, wherein the coefficient matrix
Assuming that there are (m-1) × n meshes in one region and there are m × n corresponding mesh vertices, the mesh vertices are arranged to obtain C ═ C [ -n [ -C ] ] 1 ,C 2 …C n ,C n+1 ,C n+2 …C 2n ,C (m-1)*n+1 ,C (m-1)*n+2 …C m*n ]', equation of the ith test point
(1-α i )·(1-β i )·C 2 +(1-α i )·β i ·C 3 +α i ·(1-β i )·C n+2 +α i ·β i ·C n+3 ＝ASF spacial_i ，
The matrix equation is A C ASF spacial_i Solving the matrix equation to obtain C, i.e. ASF of the grid vertex spacial The value is obtained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011365905.0A CN112636893B (en) | 2020-11-29 | 2020-11-29 | Method for improving eLoran system time service precision by using ASF grid and differential station |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011365905.0A CN112636893B (en) | 2020-11-29 | 2020-11-29 | Method for improving eLoran system time service precision by using ASF grid and differential station |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112636893A CN112636893A (en) | 2021-04-09 |
| CN112636893B true CN112636893B (en) | 2022-08-02 |
Family
ID=75306762
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011365905.0A Active CN112636893B (en) | 2020-11-29 | 2020-11-29 | Method for improving eLoran system time service precision by using ASF grid and differential station |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112636893B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107196716A (en) * | 2017-04-21 | 2017-09-22 | 中国科学院国家授时中心 | Calculate the difference method of long wave ground wave signals propagated time delay |
| CN109100931A (en) * | 2018-07-25 | 2018-12-28 | 中国科学院国家授时中心 | A kind of calculated using differential data user ASF carries out accurate modified method |
| CN111125885A (en) * | 2019-12-03 | 2020-05-08 | 杭州电子科技大学 | ASF correction table construction method based on improved kriging interpolation algorithm |
| CN111866754A (en) * | 2020-06-29 | 2020-10-30 | 湖南省时空基准科技有限公司 | Wireless broadcast time service information processing method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7782983B2 (en) * | 2006-12-18 | 2010-08-24 | Crossrate Technology Llc | Method and system for demodulation of a differential Loran C signal |
| US10778362B2 (en) * | 2018-12-21 | 2020-09-15 | Eagle Technology, Llc | Enhanced loran (eLORAN) system having divided non-station specific eLORAN data |
| US11041932B2 (en) * | 2019-02-22 | 2021-06-22 | Eagle Technology, Llc | Enhanced LORAN (eLORAN) system having corrected additional secondary factor (ASF) data |
| CN110715670A (en) * | 2019-10-22 | 2020-01-21 | 山西省信息产业技术研究院有限公司 | Method for constructing driving test panoramic three-dimensional map based on GNSS differential positioning |
-
2020
- 2020-11-29 CN CN202011365905.0A patent/CN112636893B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107196716A (en) * | 2017-04-21 | 2017-09-22 | 中国科学院国家授时中心 | Calculate the difference method of long wave ground wave signals propagated time delay |
| CN109100931A (en) * | 2018-07-25 | 2018-12-28 | 中国科学院国家授时中心 | A kind of calculated using differential data user ASF carries out accurate modified method |
| CN111125885A (en) * | 2019-12-03 | 2020-05-08 | 杭州电子科技大学 | ASF correction table construction method based on improved kriging interpolation algorithm |
| CN111866754A (en) * | 2020-06-29 | 2020-10-30 | 湖南省时空基准科技有限公司 | Wireless broadcast time service information processing method |
Non-Patent Citations (3)
| Title |
|---|
| Experimental Study on a Modified Method for Propagation Delay of Long Wave Signal;Yun Li,Yu Hua et.al;《IEEE Antennas and Wireless Propagation Letters》;20190704;全文 * |
| Universal Kriging for Loran ASF Map Generation;P. Son, J. H. Rhee, J. Hwang and J. Seo;《IEEE Transactions on Aerospace and Electronic Systems 》;20181018;全文 * |
| 一种基于差分的长波授时方法研究;燕保荣等;《天文学报》;20181123(第06期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112636893A (en) | 2021-04-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104965207A (en) | Method for acquiring area troposphere zenith delay | |
| CN110856106A (en) | Indoor high-precision three-dimensional positioning method based on UWB and barometer | |
| CN114417580B (en) | Method for evaluating influence of observation system on assimilation performance of global ionosphere data | |
| Carouge et al. | What can we learn from European continuous atmospheric CO 2 measurements to quantify regional fluxes–Part 2: Sensitivity of flux accuracy to inverse setup | |
| CN113325448A (en) | Large-altitude-difference CORS network resolving method considering troposphere delay reconstruction | |
| CN109917424B (en) | Residual error correction method for troposphere delay in NWP (N-WP) inversion under multi-factor constraint | |
| CN114019584A (en) | VRS resolving method for high-precision CORS network in large-altitude-difference area | |
| CN113791431B (en) | Peer-to-peer security satellite high-precision network enhancement method constructed based on P2P technology | |
| CN110595968B (en) | PM2.5 concentration estimation method based on geostationary orbit satellite | |
| CN113850908A (en) | Optimization method of ground flash back positioning data considering path extension factor | |
| CN107196716B (en) | Difference method for calculating long-wave ground wave signal path propagation time delay | |
| CN103592653A (en) | Ionized layer delay correction method for local area single-frequency satellite navigation user | |
| CN112636893B (en) | Method for improving eLoran system time service precision by using ASF grid and differential station | |
| CN114125699A (en) | Network RTK service method for reconstruction by using virtual reference station | |
| CN106878947B (en) | Indoor positioning method and device | |
| US10317575B2 (en) | Method and apparatus for forecasting weather | |
| CN113487100B (en) | Global accurate prediction method and system for photovoltaic power generation output | |
| CN114019585A (en) | High-precision positioning CORS network FKP resolving method for large-altitude-difference area | |
| CN114355400A (en) | Ionosphere modeling method based on ionosphere radial variation characteristics | |
| CN112198537A (en) | Rowland high-precision positioning resolving method based on difference | |
| CN113534206A (en) | Access virtual reference station quick selection mechanism based on Beidou foundation enhancement system | |
| CN114417579B (en) | Different unit grid distance conversion method for troposphere electric wave environment numerical mode result | |
| CN116299598B (en) | Bridge deformation monitoring method based on PPP-RTK and multipath correction | |
| CN116449117B (en) | Three-dimensional lightning positioning method suitable for complex terrain | |
| CN116430127B (en) | Method for reducing lightning positioning ground flash error |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |