RU2442996C1 - Method for locating satellite communication earth station - Google Patents

Abstract

FIELD: satellite control systems. ^ SUBSTANCE: satellite control system antenna is pointed on the satellite retranslating the signal of this earth station. Measuring receiver is connected to the antenna-feeder tract of the SCS station and is used to measure mean square value of retranslated signal power from simultaneously operating through retranslating satellite reference earth stations with known earth coordinates and target ES. The measurements are performed in discrete moments of time on fixed frequency of retranslated signals of ES on the observation interval TH. The results of measurements are recorded in text files and are presented in form of curves (fig.1) where on the horizontal axis there are counting numbers n=0,1,2Ç.,N - numbering of counting with spacing öt with öt=const, öt -interval between counting, and on the vertical axis there are values of counting equal to signal levels yq(n), q=1,2,Ç, q- numbering of earth stations. Using visual analysis of the dependences long-term cyclic repetition of signal level fall with short-living high frequency components. Fall of signal level is associated with its weakening when the ES- retranslating satellite is passing through the areas of volumetrically distributed hydrometeors (VDH). With such repetitions on the observation interval TH the detailed information is determined on dynamic properties of signals - parameters of reviewed repetitions (beginning, duration, ending). In order to get it the procedure of processing of discrete sequences of signal counting yq(n) is performed using the software means of discrete wavelength transformer on the base of basic Dobeshi wavelength of the 1st order on PC in MathLab program. Discrete sequences of signal counting yq(n) are decomposed into refining wavelength-coefficients 1d,n where d=1,2,Ç, D - numbering of decomposition level of different scope of signal dynamic with Dëñlog2N. Refining wavelength-coefficients 1d,n are presented in form of curves (fig.2) where on the horizontal axis are number of counting n, and on the vertical counting - values of refining wavelength-rations 1d,n that show on selected decomposition level d in different scope dynamic properties of the signal - parameters of cyclic repetition of signal level falls (beginning, duration, amount). Using visual analysis of the curves the similarity of such parameters is detected between target ES and at least one reference ES. Based on the geometric presentation of the method (fig.3) showing local homogenous area of VDH, central prospective projection of such area on the Earth surface and routes ES-retranslating satellite, it is thought that the similarity is caused by routes ES-retranslating satellite passing through the same VDH area with limited occupying space and condition of passing of different routes ES-retranslating satellite through VDH area with such characteristics is territorial proximity of ES. The area of most probable location of target ES is determined by referencing the earth coordinates of reference ES that is similar to target ES in dynamics of retranslated signals levels. ^ EFFECT: simplification and decreased realization cost of the method achieved due to locating earth station (ES) in the abovementioned way. ^ 1 dwg, 3 dwg

Description

The invention relates to the field of satellite radio monitoring, and in particular to methods for determining the location of earth stations of satellite communications (hereinafter referred to as AP) based on regularities in the dynamics of levels of relayed signals, and can be used in the search and localization of AP - sources of interference to trunks with direct relay of satellites transponders in geostationary orbit.

To date, methods for determining the location of APs were difficult to implement and required expensive equipment.

A known method for determining the coordinates of an unknown transmitter by a satellite communications system in the description of the invention to US patent No. 5008679, IPC G01S 005/02, G01S 003/02, G01S 001/24 from 01/31/1991 publ. 04/16/1991, which consists in the fact that the system uses two repeater satellites in the geostationary orbit CP1 and CP2, an unknown transmitter emits a signal in the direction of CP1 along the main lobe of the radiation pattern, and in the direction of CP2, on the side lobe, at earth stations ЗС1 and ЗС2 signals of an unknown transmitter relayed from СР1 and СР2 are received with a time shift, on the Earth’s surface, the isoline of constant differences of distances from the unknown transmitter to two points of the orbital positions СР1 and СР2 is determined, the caused With the daily movement of CP1 and with CP2, the Doppler frequency shift of the received signal, the Doppler isoline is determined on the Earth's surface - the constancy of the Doppler frequency bias for CP1 and CP2, the location of the unknown transmitter is determined as the intersection point of the Doppler and range isolines.

The disadvantage of this method is the complexity of its implementation, since it requires the choice of a pair of satellites with the coincidence of the frequency-polarization plans at closely located orbital positions.

There is also a method of determining the location of an earth station by relayed signal in the description of the invention to the patent of the Russian Federation No. 2172495, IPC G01S 5/00, G01S 5/06 from 05/06/2000, publ. 08/20/2001, consisting in the fact that a signal is received from an earth station at a receiving earth station, the values of the Doppler shift of the signal carrier frequency for the entire path "earth station - satellite-receiving earth station" are measured at the corresponding time t _i with a step Δ _t , process them, based on the processing, the values of the Doppler shift of the carrier frequency of the signal for the earth station-satellite path are calculated, characterized in that the total number Q of the measured values of the Doppler shift of the frequency of the signal for the earth station-satellite-pr path emnaya earth station "and the calculated values of Doppler shift frequency for the signal line" earth station - satellite "is selected from the condition 100≤Q≤86400 / Δ _t Δ _t and the value chosen in the range Δ _t = 30 ... 6000, said stored values and Q the corresponding moments of time t _i calculate the size of the maximum bearing base, and the bearing base is various pairs of points of the satellite’s orbit, remember it, group in pairs all possible combinations of direction finding bases on the interval of the mentioned Q values with a step n = Δ _T / Δ _t , where Δ _T - temporary step of forming bearing bases, compare the sizes of bearing bases in grouped pairs with a threshold value, select pairs of bearing bases in which both direction-finding bases are not shorter than the threshold value, measure the angle between direction-finding bases in the selected pairs of direction-finding bases, compare the measured angle with the threshold value, choose pairs of bearing bases in which the measured angle between them is not less than a threshold value, and for each of the selected pairs of bearing bases integrate on the corresponding For each direction-finding base, the time interval, the stored values of the Doppler shift of the signal carrier frequency for the earth station-satellite path are determined using the differential-ranging method to locate the earth station, and after determining the location, the coordinates of the earth station are stored, the stored coordinates are averaged, and the averaging result is determined as the final location earth station.

The disadvantage of this method is the complexity and high cost of its implementation, as it additionally requires an external source of data on the ephemeris of satellite movement in the vicinity of the nominal orbital position and a special multi-station ground-based system to eliminate the ambiguity of determining the location of the AP.

The technical result is the simplification and reduction of the cost of implementing the method.

The technical result is achieved due to the fact that the method of determining the location of the satellite earth station, which consists in receiving and measuring the parameters of relayed signals at the satellite radio monitoring station (hereinafter referred to as SRK), processing measurements, analyzing the results of processing and on this basis determining the location of the satellites, characterized in that when signals are received at the SRK station at discrete time instants with a step Δt, at Δt = const, the levels of relayed signals from simultaneously working through nick repeater reference AP with known geographical coordinates and the unknown AP, is recorded measurement results as sampled sequences of equal signal levels y _q (n), where q = 1, 2, ..., Q - AP numbering, n = 0, 1 , 2, ..., N - numbering of samples sampled sequence y _q (n) recorded in the text files and are in the form of plots by visual analysis of these curves reveal the long-term cyclical repetition falling signal level to the background to the high-frequency short-lived components, associate the drop in the signal level with their attenuation during the passage of the "ZS-satellite-relay" paths through the areas of volumetric hydrometeors (hereinafter referred to as the ORG), provided that the signal level drops are detected, the text files are processed on a personal electronic computer (hereinafter referred to as PC ) in the MathLab environment, using discrete wavelet transform software based on the Daubechies base wavelet of order 1, we obtain the detailed wavelet coefficients 1 _{d, n} , where d = 1, 2, ..., D is the numbering of the levels of decomp the positions of the sequences of discrete samples y _q (n), for D≤log ₂ N, detailing the wavelet coefficients 1 _{d, n are} represented as graphic dependences on the levels d and numbers of samples n, according to the graphic dependences of the wavelet coefficients 1 _{d, n} in different on a scale at levels d, analyze the parameters of cyclic repetitions (beginning, duration, quantity) of the drop in the level of each signal in relation to the others, using visual analysis reveal the similarity of these parameters between the desired GL and at least one of the reference GL, the reason for this convergence they consider the passage of the tracks “AP - satellite-relay” through the same area of the ORG with a limited size of occupied space, as the condition for the passage of different routes of “AP - satellite-relay” through the region of the ORG with these characteristics, take the territorial proximity of the AP, determine the binding to the geographical coordinates of the identified reference AP, the region of the most probable location of the desired AP, perform the final search and localization of the desired AP relative to the identified reference AP in the horizontal radius the length of the projection of the local homogeneous region of the ORG on Earth.

Simplification of the location of APs is achieved simultaneously with the elimination of significant financial and material costs for the deployment and operation of additional hardware due to the formalization of the regularities in the dynamics of the levels of relayed signals associated with the passage of paths "AP - satellite-relay" through the ORG, and their subsequent analysis . It does not require the choice of a pair of satellites with matching frequency-polarization plans at closely located orbital positions, which is difficult to achieve in real conditions.

In the US analogue No. 5008679, reception and processing of a low-level signal with CP2 are difficult, the choice of a pair of satellites with coincidence of frequency-polarization plans at closely located orbital positions is difficult, measures are needed to eliminate the ambiguity in determining the location. All this complicates the determination of the location of the AP.

Unlike analogs in the claimed invention, when determining the location of the AP of the search object, the antenna of the SRK station is pointed at the satellite-relay of the signals of this AP. A measuring receiver is connected to the antenna-feeder path of the SRK station to measure the rms values of the power (levels) of the relayed signals from the ST search object and the specified reference ST working simultaneously with the ST search object via this relay satellite. Measurements are performed at discrete time instants with a step Δ _t , at Δ _t = const. The measurement results are recorded in the form of sequences of discrete samples equal to the signal levels y _q (n), where q = 1, 2, ..., Q is the numbering of the AP, n = 0, 1, 2, ..., N is the numbering of the samples. The sequences of discrete samples y _q (n) are recorded in text files and presented as graphical dependencies.

In analogs, the Doppler shift of the carrier frequency of the signal is measured for the entire path "AP - satellite-relay - receiving AP". This requires an external highly stable reference generator and knowledge of the exact time, which makes the implementation of known methods more complicated compared to the claimed invention, in which signal levels are measured.

In analogs, the location of APs is determined by the difference-ranging method, which requires accurate data on the ephemeris of the relay satellite at the end points of direction finding bases. This entails additional costs for solving a number of technical problems and complicates the known methods in comparison with the claimed invention, in which such data are not used.

In analogs, when implementing the difference-ranging method, the ambiguity of determining the location of the AP arises. To eliminate this drawback, a special multi-station ground support system is additionally required. In the claimed invention use a different approach to determining the location of the AP and the need to create such a system is absent.

Unlike analogues in the claimed invention, an analysis of the patterns of dynamics of the levels of relayed signals is performed. For this, the graphical dependences y _q (n) reveal long-term cyclic repetitions of the level drop during the passage of the tracks "ZS - satellite-relay" through the regions of the ORG. After their identification, text files containing records of sequences of discrete samples y _q (n) are processed on a personal computer in the MathLab environment by means of a discrete wavelet transform software based on a basic Daubechies wavelet of order 1. Receive detailed wavelet coefficients 1 _{d, n} , where d = 1, 2, ..., D is the numbering of the levels of decomposition of the sequences of discrete samples y _q (n) for D ≤ log ₂ N. The detailed wavelet coefficients 1 _{d, n are} presented in the form of graphs that show at different scales on the selected levels of decomposition d dynamic features of signals - parameters of cyclic repetitions of a drop in the level of signals (beginning, duration, quantity). Using a visual analysis of the graphs, the similarity of these parameters between the desired GL and at least one of the reference GLs is revealed. The reason for this similarity is considered to be the passage of the tracks "AP - satellite-relay" through the same area of the ORG with a limited size of the occupied space. As a condition for the passage of different paths "AP - satellite-relay" through the area of the ORG with these characteristics take the territorial proximity of the AP. Determine by reference to the geographic coordinates of the identified reference AP the region of the most probable location of the desired AP. Next, they carry out the final search and localization of the desired ES with respect to the identified reference ES in the radius of the horizontal extent of the projection of the local homogeneous region of the ORG onto the Earth. The inventive method has a novelty in comparison with the known methods, differing from them in such a significant feature as taking into account patterns in the dynamics of the levels of relayed signals and using the similarities of these patterns to determine the location of the AP during the passage of the paths "AP - satellite-relay" through the ORG region. All this leads to a simplification of methods for determining the location of the AP.

The analysis of the prior art showed that the claimed combination of essential features set forth in the claims is unknown. This allows us to conclude that it meets the criterion of "novelty." To verify the conformity of the claimed invention with the criterion of "inventive step", an additional search was carried out for known technical solutions in order to identify features that match the distinctive features of the claimed technical solution from the prototype. It is established that the claimed technical solution does not follow explicitly from the prior art. Therefore, the claimed invention meets the criterion of "inventive step".

The essence of the method and the possibility of its implementation are illustrated by figures 1, 2, 3, where

figure 1 in graphical form shows a discrete sequence of samples of levels of relay signals of the AP;

figure 2 in graphical form shows the decomposition of discrete sequences of samples of relayed signals of the AP on the levels d8-d12;

figure 3 shows a diagram of a geometric representation of the implementation of the method.

The inventive method is as follows.

When determining the location of the desired AP, the antenna of the SRK station is pointed at the satellite through which the signals of this AP are relayed. A measuring receiver is connected to the antenna-feeder path of the SRK station, with the help of which the mean-square power values (levels) of relayed signals are measured, working simultaneously through the satellite-relay of the desired and reference ZS (with known geographical coordinates). Measurements are performed at discrete time instants at fixed frequencies of relay signals of the ES in the observation interval T _n . The measurement results are recorded in text files and presented in the form of graphical dependencies (Fig. 1), where the numbers of samples n = 0, 1, 2, ..., N are plotted along the abscissa, the numbering of samples, in increments of Δt, with Δt = const, Δ _t is the interval between samples, along the ordinate axis, the values of samples equal to the signal levels y _q (n), q = 1, 2, ..., Q are the numbering of APs. Using a visual analysis of the dependencies (see Fig. 1), long-term cyclic repetitions of a drop in the signal level against the background of short-lived high-frequency components are revealed. The drop in the signal level is associated with their attenuation during the passage of the paths "ZS - satellite-relay" through the regions of the ORG. In the presence of such repetitions on the observation interval T _n determine detailed information about the dynamic characteristics of the signals - the parameters of the repetitions under consideration (start, duration, quantity). To obtain it, use the procedure for processing discrete sequences of samples of signals _{q q} (n) using discrete wavelet transform software based on a basic Daubechies wavelet of order 1 on a PC in MathLab. Discrete sequences of signal samples y _q (n) are decomposed into detailed wavelet coefficients 1 _{d, n} , where d = 1, 2, ..., D is the numbering of decomposition levels of different scales of signal dynamics at D≤og ₂ N. Detailed wavelet coefficients l _{d, n are} presented in the form of graphs (Fig. 2), where the numbers of samples n are plotted on the abscissa axis, and the values of the detailed wavelet coefficients 1 _{d, n} on the ordinate axis, which show the dynamic characteristics of the signals at different levels of decomposition d at different scales - parameters of cyclic tendencies of falling signal level (beginning, duration, quantity). Using a visual analysis of the graphs (see figure 2) reveal the similarity of such parameters between the desired ES and at least one of the reference ES. Based on the geometric representation of the method (figure 3), which shows the local homogeneous region of the ARG (horizontal length of 20-50 km), the central perspective projection of this region on the Earth's surface (commensurate with the horizontal length of the ORG region) and the track "AP - satellite-relay ", They believe that the reason for this similarity is the passage of the tracks" AP - satellite-relay "through the same area of the ORG with a limited size of the occupied space, and the condition for the passage of different paths" AP - satellite-relay FES through the region with such characteristics is the geographic proximity of AP. The region of the most probable location of the search object of the search is determined by reference to the geographic coordinates of the reference AP, which is similar to the search object in the dynamics of the levels of relayed signals. Search and localization of the desired object is carried out with respect to the identified reference GL within a radius comparable with the horizontal extent of the projection of the ORG region onto the Earth (the accuracy of determining the location is limited by the horizontal extent of the projection of the ORG region onto the Earth, which can be 20 ... 50 km).

The method extends to the reception of signals by the SRK station in clear sky conditions when operating the AP without tuning frequency tuning and with constant radiated power.

An example implementation of the proposed method.

A method for determining the location of a satellite earth station is as follows. The antenna of the SRK station is pointed at the satellite, through which the signal of the search object is relayed. The levels of relayed signals simultaneously working through the satellite-relay of the desired and reference ZS are measured by a measuring receiver connected to the antenna-feeder path of the SRK station. A rms detector is used in the measuring receiver. For guaranteed overlapping of the moments of the beginning and end of the “life” time of the regions of the ORG, the observation interval T _{n is} chosen to be about 24 hours. In this case, implementations of signals with a duration of N = 4096 samples are used, decomposition is carried out at D = 12 decomposition levels at D≤log ₂ N. Discrete sequences of samples are recorded in text files. When detecting long-term cyclic repetitions of a drop in the level (see Fig. 1), the text files of the signals are processed on a personal computer in the MathLab environment by means of a discrete wavelet transform software based on a basic Daubechies wavelet of order 1. The processing results are displayed in the form of graphs detailing the wavelet coefficients (see Fig. 2), which show details of the dynamics of the signals of the ES at the selected levels of decomposition (d8 is the closest approximation to the original signals, and d12 is the most distant). According to the graphs (see figure 2) using visual analysis to determine the characteristics of each signal (start, duration, number of repetitions of the level drop) in relation to others and establish that the reference 3C2 is similar to the search object 3C1. The region of the most probable location of the desired ZS1 is determined by reference to the geographical coordinates of the reference ZS2. Search and localization of ZS1 is carried out with respect to the identified reference ZS2 in a radius of up to 50 km, commensurate with the most probable horizontal extent of the projection of a homogeneous local region of the Earth’s Earth and Earth.

Technical appraisal and economic effect.

The use of the proposed method since 2009 when operating a stationary RCC of the radio monitoring department of satellite radio communication services of a branch of the Federal State Unitary Enterprise Central Federal District in the Voronezh Region experimentally confirmed the possibility of locating and locating an AP with an accuracy of up to 50 km based on formalization and analysis of patterns of dynamics of levels of relayed signals. The application of the method allows to simplify the determination of the location of the satellite earth station while eliminating the costs of the deployment and operation of additional hardware.

Claims (1)

A method for determining the location of a satellite communications earth station, comprising receiving and measuring the parameters of relay signals of satellite communications earth stations at a satellite radio monitoring station, processing measurements, analyzing processing results, and based on this, determining the location of a satellite communications earth station, characterized in that when receiving signals on satellite monitoring stations at discrete time instants with a step Δ _t , at Δ _t = const, measure the levels of relayed signals from simultaneously working Using satellite-relay of reference satellite earth stations with known geographical coordinates and the desired satellite earth station, the measurement results are recorded in the form of sequences of discrete samples equal to signal levels y _q (n), where q = 1, 2, ..., Q - numbering of satellite earth stations, n = 0, 1, 2, ..., N - numbering of samples, sequences of discrete samples y _q (n) are recorded in text files and presented in the form of graphical dependencies, by visual analysis of these dependencies long-term cyclic repetitions of a drop in the signal level against the background of short-lived high-frequency components, connect the drop in the signal level with their attenuation during the passage of the satellite earth station - satellite-relay routes through the areas of spatially distributed hydrometeors, provided that the signal level drops are detected, text files are processed on a personal electronic computer in a MathLab environment using discrete wavelet transform software based on the Daubechies base wavelet oryadka 1, the detailing wavelet coefficients 1, _{d, n,} where d = 1, 2, ..., D - numbering decomposition levels sampled sequence y _q (n), at D≤log ₂ N, detailing wavelet coefficients 1 _{d, n are} represented as graphical dependences on levels d and sample numbers n, according to the graphical dependences of the wavelet coefficients 1 _{d, n} on a different scale at levels d, parameters of cyclic repetitions (beginning, duration, quantity) of the level drop of each signal relative to others are analyzed, using visual analysis revealed they show the similarity between the desired satellite earth station and at least one of the satellite earth reference stations, the reason for this similarity is the passage of the satellite earth station - satellite-relay routes through the same area of spatially distributed hydrometeors with a limited size space, as a condition for the passage of different routes "satellite earth station - satellite-relay" through the region of spatially distributed hydrometeors with such characteristics they accept the territorial proximity of satellite earth stations, determine the region of the most probable location of the desired satellite earth station by geographic coordinates of the identified satellite earth station, perform the final search and localization of the desired satellite earth station with respect to the identified satellite earth station in the horizontal radius the projection length of a local homogeneous region of spatially distributed hydrometeors on The earth.

Images