CN116593959B - Method and system for positioning radiation source by mutual ambiguity function mapping based on carrier frequency search - Google Patents
Method and system for positioning radiation source by mutual ambiguity function mapping based on carrier frequency search Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/0246—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves involving frequency difference of arrival or Doppler measurements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/0205—Details
- G01S5/0221—Receivers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/0278—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves involving statistical or probabilistic considerations
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention discloses a method and a system for positioning a radiation source by mutual ambiguity function mapping based on carrier frequency search, which solve the technical problem that the radiation source cannot be positioned when the carrier frequency of the radiation source is difficult to judge in the face of unknown signals, and belong to the field of radiation source positioning, and comprise the following steps: dividing grid points for a target area to obtain a time-frequency difference lookup table; determining a searching range and a searching step length of searching carrier frequencies; obtaining a time difference value and a frequency difference value corresponding to the search carrier frequency according to the time frequency difference lookup table, and obtaining a time frequency difference range; obtaining a mutual fuzzy function value through a mutual fuzzy function model and mapping the mutual fuzzy function value on grid points to form a distribution diagram; updating the searching carrier frequency according to the searching step length until the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all the mapped mutual fuzzy function values; obtaining the carrier frequency estimated value and the position of the radiation source; the invention does not need carrier frequency estimation, and realizes carrier frequency estimation while successfully positioning the radiation source through carrier frequency searching accumulation.
Description
Technical Field
The invention belongs to the technical field of passive positioning of radiation sources, and relates to a method and a system for positioning a radiation source by mutual ambiguity function mapping based on carrier frequency searching.
Background
Signals such as broadcasting, television, navigation and the like are often easily interfered by ground radiation sources, and in order to ensure normal transmission and reception of the signals and avoid interference, the radiation sources generating interference signals need to be positioned.
In the prior art, the radiation source is generally positioned by adopting a traditional positioning method, a direct positioning method, a mutual fuzzy function mapping method and the like;
the method generally comprises multi-station direction-finding cross positioning, time difference positioning, frequency difference positioning and time-frequency difference combined positioning, wherein specific parameters such as angles, time difference values and frequency difference values of a receiver relative to a radiation source are measured, then a positioning equation is solved according to the obtained parameter values, and finally the estimation of the position of the radiation source is obtained. Such as "passive positioning principle and method" Guo Fucheng.
In the direct positioning method, signal parameter values such as angles, time differences, frequency differences and the like are not measured, sampling signals are directly used as input, a cost function is constructed, and the position estimation of the radiation source is obtained under the condition of not measuring the parameters in an exhaustive search mode. Such as: wu Guizhou, guo Fucheng, zhang Min. General review of direct Signal positioning techniques [ J ]. Radar journal, 2020,9 (6): 16.
The mutual blur function mapping method mainly relies on the basic principle that the main correlation peak value of the stationary radiation source is completely consistent with all the mutual blur function amplitudes, and all the mutual blur function amplitudes are mapped and combined in a common geographic framework to form an image similar to radio imaging. Dividing a target area into grid points, calculating to obtain a time-frequency difference lookup table, calculating a mutual blurring function in a time-frequency difference range, mapping the mutual blurring function value onto the grid points according to the time-frequency difference lookup table, and finally obtaining the estimation of the position of the radiation source. For example: hartwell G D.improved geo-spatial resolution using a modified approach to the Complex Ambiguity Function (CAF) [ J ]. Thesis Collection,2005, which also eliminates the numerical estimates required for conventional positioning methods and thus is also a direct positioning method.
For the situation that carrier frequency signals of the target radiation source are different, various current direct positioning methods need to estimate the carrier frequency of the target radiation source, input the carrier frequency of the target radiation source as a known quantity, and then position the target radiation source, otherwise, the positioning of the radiation source cannot be realized; in the face of unknown signals, the carrier frequency of the target radiation source is often difficult to judge, so that the prior art has certain limitation in application.
Disclosure of Invention
Aiming at the technical problem that the positioning of the target radiation source cannot be realized when the carrier frequency of the target radiation source is difficult to judge in the prior art, the invention provides a mutual ambiguity function mapping radiation source positioning method and a system based on carrier frequency searching, which can realize the positioning under the condition of not inputting the carrier frequency of the target radiation source, successfully position the radiation sources of different carrier frequencies through carrier frequency searching accumulation under the premise of not estimating the carrier frequency, and can additionally realize the estimation of the target carrier frequency in the positioning process.
The aim of the invention is realized by the following technical scheme:
the invention discloses a method for positioning a radiation source by mutual ambiguity function mapping based on carrier frequency searching, which comprises the following steps:
dividing a grid point for a radiation source target area, and generating a time-frequency difference lookup table through a time difference value and a frequency difference value of a radiation source signal corresponding to the grid point;
step two, determining a searching range and a searching step length of a searching carrier frequency of the radiation source signal, and obtaining an initial carrier frequency of the searching carrier frequency according to the searching range;
thirdly, obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
step four, using a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual blurring function model, obtaining a mutual blurring function value through the mutual blurring function model, mapping the mutual blurring function value onto grid points, and forming a distribution diagram on the grid points;
step five, obtaining a real-time carrier frequency in a searching range according to the initial carrier frequency and the searching step length, updating the initial carrier frequency of the searching carrier frequency into the real-time carrier frequency, returning to the step three until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all mapped mutual fuzzy function values;
step six, obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; and meanwhile, the position coordinates of the radiation source are obtained through the peak value coordinate positioning in the distribution diagram.
In the first step, dividing the target area of the radiation source into grid points, and generating a time-frequency difference lookup table by the time difference value and the frequency difference value of the radiation source signals corresponding to the grid points, wherein the method comprises the following steps:
presetting a corresponding number of radiation source target area positioning coverage areas according to target radiation source positioning task requirements; grid division is carried out on a preset positioning coverage range of a radiation source target area to obtain a grid point set and a geographic coordinate set corresponding to the grid point set;
according to the geometric distribution relation between at least two receivers and the grid point set, calculating the time difference value and the frequency difference value of the arrival of the radiation source signals received by at least two receivers corresponding to each grid point through the geographic coordinate set corresponding to the grid point set, and generating a time-frequency difference lookup table uniquely corresponding to the radiation source signals and the grid points based on the time difference value and the frequency difference value.
In the second step, the searching range and searching step length of the searching carrier frequency of the radiation source signal are determined, and the method for obtaining the initial carrier frequency of the searching carrier frequency according to the searching range comprises the following steps:
determining a bandwidth range of a receiver receiving the radiation source signal as a search range of a search carrier frequency of the radiation source signal, and setting a minimum value of the search range as an initial carrier frequency of the search carrier frequency;
the search step length of the search carrier frequency of the radiation source signal is determined according to the precision requirement of the carrier frequency estimation.
Thirdly, obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; the method for obtaining the frequency difference table by summarizing the frequency difference values according to the frequency difference lookup table to obtain the frequency difference value corresponding to the initial carrier frequency of the search carrier frequency comprises the following steps:
obtaining the distance difference between at least two receivers receiving the initial carrier frequency of the search carrier frequency and the grid point in the search range according to the time-frequency difference lookup table, obtaining the time difference value from the grid point to at least two receivers by using the calculation method of the distance difference/the light speed, namely obtaining the time difference value corresponding to the initial carrier frequency of the search carrier frequency, and summarizing the time difference value to obtain a time difference table;
in the searching range, according to the time-frequency difference lookup table, obtaining the radial speed difference between at least two receivers receiving the initial carrier frequency of the searching carrier frequency and the grid point, and using the speed difference multiplied by the operation method of searching carrier frequency/light speed to obtain the difference between the Doppler frequencies of the grid point relative to at least two receivers, namely obtaining the frequency difference value corresponding to the initial carrier frequency of the searching carrier frequency, and summarizing the frequency difference values to obtain the frequency difference table.
In the third step, the method for determining the time-frequency difference range through the time difference table and the frequency difference table comprises the following steps:
obtaining a time difference range represented by the maximum time difference value and the minimum time difference value according to the time difference table;
obtaining a frequency difference range represented by the maximum frequency difference value and the minimum frequency difference value according to the frequency difference table;
and setting an error range to obtain a time-frequency difference range of the coverage time-frequency difference lookup table, wherein the time-difference range comprises the error range and the frequency-frequency difference range comprises the error range.
In the fourth step, the mutual ambiguity function model is:
wherein CAF (τ, f d ) Is a mutual blurring function model; receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Time difference values of (2); f (f) d Is the time-frequency differenceThe second receiver in the enclosure receives the radiation source signal r 2 Receiving a radiation source signal r relative to a first receiver 1 Frequency difference value of (2); t is the total duration of receiving the radiation source signal; r is (r) 1 (t) receiving a time domain sample of the radiation source signal for the first receiver; r is (r) 2 (t+τ) is the time-domain sampling result of the radiation source signal received by the second receiver with the time difference value τ;a second receiver which is the time difference value tau receives conjugation of the time domain sampling result of the radiation source signal; t is a sampling time point; e is a natural constant; j is the sign of the imaginary number.
In the fourth step, the mutual ambiguity function value is mapped to a grid point, and the step of forming a distribution diagram on the grid point comprises the following steps:
corresponding the time difference coordinates of the mutual ambiguity function values to grid point time difference values;
corresponding the frequency difference coordinates of the mutual ambiguity function values to the grid point frequency difference values;
thereby, the grid points are corresponding to the mutual fuzzy function values, and a distribution diagram of the mutual fuzzy function values on the grid points is obtained;
the time difference value and the peak coordinates of the frequency difference value of the grid points are displayed in the distribution diagram.
In the fifth step, in the searching range, the real-time carrier frequency is obtained according to the initial carrier frequency and the searching step length, the initial carrier frequency of the searching carrier frequency is updated to the real-time carrier frequency, the third step is returned until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, the carrier frequency searching is completed, and the method for accumulating all the mapped mutually fuzzy function values comprises the following steps:
in the searching range, adding the initial carrier frequency and the searching step length to obtain a real-time carrier frequency, replacing the initial carrier frequency of the searching carrier frequency with the real-time carrier frequency, updating the searching carrier frequency, and returning to the step three;
obtaining a time difference value corresponding to the real-time carrier frequency of the search carrier frequency according to the time frequency difference lookup table, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the real-time carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
using a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual blurring function model, obtaining a mutual blurring function value through the mutual blurring function model, and mapping the mutual blurring function value to a previous distribution diagram;
each mapping is accumulated on the basis of the original distribution diagram until the searching carrier frequency is updated to the maximum value of the searching range, carrier frequency searching is completed, and the mutual ambiguity function values of all the mappings are accumulated.
Step six, obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; the method for obtaining the position coordinates of the radiation source through peak coordinate positioning in the distribution diagram comprises the following steps:
obtaining a maximum mutual blur function value in a distribution diagram according to the distribution diagram of the accumulated mapped mutual blur function values on grid points, wherein the real-time carrier frequency corresponding to the maximum mutual blur function value is a carrier frequency estimated value of the radiation source;
for example: obtaining a carrier frequency estimated value parameter range of the radiation source corresponding to the mutual blurring function value based on the mutual blurring function value in the distribution diagram; deriving carrier frequency estimated value parameters to obtain a data change rate; the inflection point of the data change rate, namely the maximum value position where the derivative of the carrier frequency estimation value parameter is 0, and the real-time carrier frequency corresponding to the obtained maximum mutual ambiguity function value is the carrier frequency estimation value of the radiation source;
and extracting the peak coordinates in the distribution diagram to obtain the position coordinates of the target radiation source.
The invention also discloses a system for positioning the radiation source by the mutual ambiguity function mapping based on carrier frequency searching, which comprises the following steps:
the grid point dividing module is used for dividing the target area of the radiation source into grid points, and generating a time-frequency difference lookup table through the time difference value and the frequency difference value of the radiation source signals corresponding to the grid points;
the searching carrier frequency determining module is used for determining the searching range and the searching step length of the searching carrier frequency of the radiation source signal and obtaining the initial carrier frequency of the searching carrier frequency according to the searching range;
the time-frequency difference range determining module is used for obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time-frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
the mutual fuzzy function value mapping module is used for taking a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual fuzzy function model, obtaining a mutual fuzzy function value through the mutual fuzzy function model, mapping the mutual fuzzy function value, and forming a distribution diagram on grid points;
the carrier frequency searching module is used for obtaining a real-time carrier frequency in a searching range according to the initial carrier frequency and the searching step length, updating the initial carrier frequency of the searching carrier frequency into the real-time carrier frequency, and re-calling the time frequency difference range determining module until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all the mapped mutual fuzzy function values;
the radiation source positioning module is used for obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; and meanwhile, the position coordinates of the radiation source are obtained through the peak value coordinate positioning in the distribution diagram.
The beneficial effects of the invention are as follows:
the invention increases the carrier frequency searching and accumulating positioning process:
1. the sampling signal is directly used as calculation input without measuring signal parameters, so that the precision loss of intermediate parameter estimation is avoided;
2. the radiation source can be positioned without carrying out carrier frequency estimation on the signals independently in carrier frequency searching and accumulated positioning modes;
3. the method has the advantages that the target positioning and the target signal carrier frequency estimation are simultaneously carried out in the carrier frequency searching and accumulated positioning modes, and a reference is provided for subsequent signal sorting processing.
Drawings
The invention is described in further detail below with reference to the drawings and examples.
Fig. 1 is a meshing schematic diagram.
Fig. 2 is a diagram showing the intention of the time difference.
Fig. 3 is a frequency offset representation intent.
Fig. 4 is a schematic diagram of the result of the calculation of the mutual blur function value.
Fig. 5 is an overview diagram of the positioning result of a radiation source searching carrier frequency of 2GHz with different signal carrier frequencies and no noise.
FIG. 6 is a top view of the result of locating a radiation source at a search carrier frequency of 2GHz with different signal carrier frequencies and no noise.
Fig. 7 is an overview diagram of the positioning results of a 2.5GHz carrier frequency searching radiation source with different signal carrier frequencies and no noise.
FIG. 8 is a top view of the results of searching for a carrier frequency 2.5GHz radiation source with different signal carrier frequencies, no noise, and the like.
Fig. 9 is an overview diagram of the positioning results of the 2.8GHz carrier frequency searching radiation source with different signal carrier frequencies and no noise.
FIG. 10 is a top view of the results of searching for a carrier frequency 2.8GHz radiation source with different signal carrier frequencies, no noise, and no noise.
Fig. 11 is an overview schematic of the radiation source signal positioning results of the present disclosure.
Fig. 12 is a schematic top view of the result of positioning a radiation source signal in accordance with the present disclosure.
Fig. 13 is a schematic diagram of the result of calculating the mutual blur function value at the radiation source coordinate point.
Detailed Description
Example 1
The first embodiment of the invention provides a method for positioning a radiation source mapped by a mutual ambiguity function based on carrier frequency searching, which comprises the following steps:
dividing a grid point for a radiation source target area, and generating a time-frequency difference lookup table through a time difference value and a frequency difference value of a radiation source signal corresponding to the grid point;
step two, determining a searching range and a searching step length of a searching carrier frequency of the radiation source signal, and obtaining an initial carrier frequency of the searching carrier frequency according to the searching range;
thirdly, obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
step four, using a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual blurring function model, obtaining a mutual blurring function value through the mutual blurring function model, mapping the mutual blurring function value onto grid points, and forming a distribution diagram on the grid points;
step five, obtaining a real-time carrier frequency in a searching range according to the initial carrier frequency and the searching step length, updating the initial carrier frequency of the searching carrier frequency into the real-time carrier frequency, returning to the step three until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all mapped mutual fuzzy function values;
step six, obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; and meanwhile, the position coordinates of the radiation source are obtained through the peak value coordinate positioning in the distribution diagram.
In the first step, dividing the target area of the radiation source into grid points, and generating a time-frequency difference lookup table by the time difference value and the frequency difference value of the radiation source signals corresponding to the grid points, wherein the method comprises the following steps:
presetting a corresponding number of radiation source target area positioning coverage areas according to target radiation source positioning task requirements;
grid division is carried out on a preset positioning coverage range of a radiation source target area to obtain a grid point set and a geographic coordinate set corresponding to the grid point set;
according to the geometric distribution relation between at least two receivers and the grid point set, calculating the time difference value and the frequency difference value of the arrival of the radiation source signals received by at least two receivers corresponding to each grid point through the geographic coordinate set corresponding to the grid point set, and generating a time-frequency difference lookup table uniquely corresponding to the radiation source signals and the grid points based on the time difference value and the frequency difference value.
According to the technical scheme disclosed by the invention, when a plurality of receivers are selected, the technical scheme of the invention can be realized in a pairwise pairing mode.
In the second step, the searching range and searching step length of the searching carrier frequency of the radiation source signal are determined, and the method for obtaining the initial carrier frequency of the searching carrier frequency according to the searching range comprises the following steps:
determining a bandwidth range of a receiver receiving the radiation source signal as a search range of a search carrier frequency of the radiation source signal, and setting a minimum value of the search range as an initial carrier frequency of the search carrier frequency;
the search step length of the search carrier frequency of the radiation source signal is determined according to the precision requirement of the carrier frequency estimation.
Thirdly, obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; the method for obtaining the frequency difference table by summarizing the frequency difference values according to the frequency difference lookup table to obtain the frequency difference value corresponding to the initial carrier frequency of the search carrier frequency comprises the following steps:
obtaining the distance difference between at least two receivers receiving the initial carrier frequency of the search carrier frequency and the grid point in the search range according to the time-frequency difference lookup table, obtaining the time difference value from the grid point to at least two receivers by using the calculation method of the distance difference/the light speed, namely obtaining the time difference value corresponding to the initial carrier frequency of the search carrier frequency, and summarizing the time difference value to obtain a time difference table;
in the searching range, according to the time-frequency difference lookup table, obtaining the radial speed difference between at least two receivers receiving the initial carrier frequency of the searching carrier frequency and the grid point, and using the speed difference multiplied by the operation method of searching carrier frequency/light speed to obtain the difference between the Doppler frequencies of the grid point relative to at least two receivers, namely obtaining the frequency difference value corresponding to the initial carrier frequency of the searching carrier frequency, and summarizing the frequency difference values to obtain the frequency difference table.
In the third step, the method for determining the time-frequency difference range through the time difference table and the frequency difference table comprises the following steps:
obtaining a time difference range represented by the maximum time difference value and the minimum time difference value according to the time difference table;
obtaining a frequency difference range represented by the maximum frequency difference value and the minimum frequency difference value according to the frequency difference table;
and setting an error range to obtain a time-frequency difference range of the coverage time-frequency difference lookup table, wherein the time-difference range comprises the error range and the frequency-frequency difference range comprises the error range.
In the fourth step, the mutual ambiguity function model is:
wherein CAF (τ, f d ) Is a mutual blurring function model; receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Time difference values of (2); f (f) d For receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Frequency difference value of (2); t is the total duration of receiving the radiation source signal; r is (r) 1 (t) receiving a time domain sample of the radiation source signal for the first receiver; r is (r) 2 (t+τ) is the time-domain sampling result of the radiation source signal received by the second receiver with the time difference value τ;a second receiver which is the time difference value tau receives conjugation of the time domain sampling result of the radiation source signal; t is a sampling time point; e is a natural constant; j is the sign of the imaginary number.
In the fourth step, the mutual ambiguity function value is mapped to a grid point, and the step of forming a distribution diagram on the grid point comprises the following steps:
corresponding the time difference coordinates of the mutual ambiguity function values to grid point time difference values;
corresponding the frequency difference coordinates of the mutual ambiguity function values to the grid point frequency difference values;
thereby, the grid points are corresponding to the mutual fuzzy function values, and a distribution diagram of the mutual fuzzy function values on the grid points is obtained;
the time difference value and the peak coordinates of the frequency difference value of the grid points are displayed in the distribution diagram.
In the fifth step, in the searching range, the real-time carrier frequency is obtained according to the initial carrier frequency and the searching step length, the initial carrier frequency of the searching carrier frequency is updated to the real-time carrier frequency, the third step is returned until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, the carrier frequency searching is completed, and the method for accumulating all the mapped mutually fuzzy function values comprises the following steps:
in the searching range, adding the initial carrier frequency and the searching step length to obtain a real-time carrier frequency, replacing the initial carrier frequency of the searching carrier frequency with the real-time carrier frequency, updating the searching carrier frequency, and returning to the step three;
obtaining a time difference value corresponding to the real-time carrier frequency of the search carrier frequency according to the time frequency difference lookup table, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the real-time carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
using a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual blurring function model, obtaining a mutual blurring function value through the mutual blurring function model, and mapping the mutual blurring function value to a previous distribution diagram;
each mapping is accumulated on the basis of the original distribution diagram until the searching carrier frequency is updated to the maximum value of the searching range, carrier frequency searching is completed, and the mutual ambiguity function values of all the mappings are accumulated.
Step six, obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; the method for obtaining the position coordinates of the radiation source through peak coordinate positioning in the distribution diagram comprises the following steps:
obtaining a maximum mutual blur function value in a distribution diagram according to the distribution diagram of the accumulated mapped mutual blur function values on grid points, wherein the real-time carrier frequency corresponding to the maximum mutual blur function value is a carrier frequency estimated value of the radiation source;
for example: obtaining a carrier frequency estimated value parameter range of the radiation source corresponding to the mutual blurring function value based on the mutual blurring function value in the distribution diagram; deriving carrier frequency estimated value parameters to obtain a data change rate; the inflection point of the data change rate, namely the real-time carrier frequency corresponding to the maximum mutual ambiguity function value obtained at the maximum value position where the derivative of the carrier frequency estimation value parameter is 0 is the carrier frequency estimation value of the radiation source;
and extracting the peak coordinates in the distribution diagram to obtain the position coordinates of the target radiation source.
The following provides a simulation verification test, and the detailed description of the method provided by the invention is as follows:
under the condition that the signal power, the carrier frequency, the bandwidth and the modulation type of the radiation source are the same, different actual carrier frequencies are selected, so that the carrier frequency estimation value of the invention is conveniently verified, and a plurality of radiation source parameters are set as shown in table 1:
TABLE 1
As shown in fig. 1, the preset multi-radiation source target area positioning coverage area is subjected to grid division, so as to obtain a series of grid points and corresponding geographic coordinates. And then according to the geometric distribution relation between the at least two receivers and the grid points, the time difference value and the frequency difference value of arrival of the multi-radiation source signals received by the at least two receivers corresponding to each grid point can be calculated, and a time-frequency difference lookup table uniquely corresponding to the multi-radiation source signals and the grid points is obtained based on the time difference value and the frequency difference value.
For radiation source signals received by the receiver, the carrier frequency search range may be determined based on the receiver bandwidth. For example, for a receiver with a reception bandwidth of 2GHz to 4GHz, the carrier frequency search range may be set to [2GHz,4GHz ]. The step length of carrier frequency searching can be set according to the precision requirement of carrier frequency estimation, when the step length is larger, the positioning is faster, but the precision of carrier frequency estimation is reduced, and the smaller the value, the higher the precision of carrier frequency estimation is, for example, the carrier frequency estimation can be set to be 100MHz.
And setting the searching carrier frequency as an initial carrier frequency of 2GHz according to the set searching range.
According to the searching carrier frequency at this time, namely the initial carrier frequency of 2GHz, the time difference value and the frequency difference value of each grid point can be obtained, and the time difference table and the frequency difference table can be obtained by summarizing, as shown in fig. 2 and 3.
The time difference value is calculated by the following steps: and in the searching range, obtaining the distance difference between any two receivers of the initial carrier frequency of 2GHz for receiving the searching carrier frequency and the grid point according to the time-frequency difference lookup table, and obtaining the time difference value from the grid point to the two receivers by using the distance difference/light speed operation method, thus obtaining the time difference value corresponding to the initial carrier frequency of the searching carrier frequency.
The frequency difference value is calculated by the following steps: according to the time-frequency difference lookup table, obtaining the radial speed difference between any two receivers receiving the initial carrier frequency of 2GHz of the search carrier frequency and the grid point, and obtaining the difference between Doppler frequencies of the grid point relative to the two receivers by using the speed difference multiplied by the operation method of the search carrier frequency/light speed, thereby obtaining the frequency difference value corresponding to the initial carrier frequency of the search carrier frequency.
Summarizing the time difference values to obtain a time difference table, and summarizing the frequency difference values to obtain a frequency difference table; and obtaining the maximum and minimum values of the time difference value and the frequency difference value according to the time difference table and the frequency difference table. On the basis of the above-mentioned method, the calculation range of the mutual blur function value can be defined, i.e. minimum value to maximum value of time difference and minimum value to maximum value of frequency difference. During calculation, an error range is set, the time-frequency difference range can be obtained by expanding the time-frequency difference range and the frequency-frequency difference range, and the calculated mutual ambiguity function value is ensured to cover the numerical range in the whole time-frequency difference lookup table.
Within the time-frequency difference range of the coverage grid points, the mutual blurring function model is adoptedThe value of the mutual ambiguity function is calculated as shown in fig. 4.
The initial carrier frequency 2GHz of the searched carrier frequency is input into a mutual ambiguity function model, and the mutual ambiguity function value is mapped to grid points in the step. It can be found that each of the mutual ambiguity function values has corresponding time difference coordinates and frequency difference coordinates, and each of the grid points has corresponding time-frequency difference values. The grid points and the mutual blur function values can be corresponding through the time-frequency difference value, so that a distribution diagram of the mutual blur function values on the grid points is obtained, as shown in fig. 5 and 6.
It can be seen from fig. 5 and 6 that only the coordinate point latitude=20 and longitude=68 is relatively prominent, whereas the carrier frequency of the radiation source a at this coordinate point is 2.3GHz, as is known from the previous radiation source parameters. Whereas the carrier frequency of the first radiation source a is closest to 2GHz compared to the other radiation sources, so that a distinct peak is obtained at the corresponding coordinates.
And (3) obtaining real-time carrier frequency according to the previously set searching step length, updating the searching carrier frequency, returning to the step (III), inputting the updated searching carrier frequency, namely searching the real-time carrier frequency again, mapping the mutual ambiguity function value onto the result obtained in the last cycle, and accumulating each mapping on the original basis until the searching carrier frequency is updated to the maximum value of the previously set searching range. Fig. 7 and 8 are positioning results when the search carrier frequency is 2.5 GHz; fig. 9 and 10 are positioning results when the search carrier frequency is 2.8 GHz.
It can be found that as the real-time carrier frequency input value gradually approaches the actual carrier frequency of the radiation source, the mutual ambiguity function value at the corresponding radiation source coordinates gradually increases. Namely, under the condition that the signal carrier frequencies of the radiation sources are different, the search of the signal carrier frequencies is added on the basis of grid search, so that the radiation sources with different carrier frequencies are positioned.
After the search is completed, all the mutual ambiguity function values are accumulated to obtain the result as shown in fig. 11 and 12.
It can be seen that 5 distinct peaks appear in fig. 11 and 12, the coordinates of which coincide with the previously set coordinates of the 5 radiation sources. The result shows that the problem of positioning the radiation sources with different carrier frequencies can be effectively solved by accumulating the cost function of the mutual ambiguity function values after carrier frequency step search.
And extracting the peak coordinates in the accumulated function images to obtain the positioning result of the radiation source.
In the carrier frequency searching process, the closer the real-time carrier frequency of the searching carrier frequency is to the actual carrier frequency of the radiation source, the larger the calculation result of the cost function of the mutual ambiguity function value corresponding to the coordinate point of the radiation source is, so that the parameter range of the actual carrier frequency of the corresponding radiation source can be obtained according to the change condition of the cost function, and a certain reference is provided for signal sorting.
Fig. 13 shows a variation of the result of calculation of the cost function at the radiation source coordinate point during carrier frequency searching.
The data of fig. 13 is then derived to obtain the data change rate. The inflection point of the data change, namely the position with the derivative of 0, and the carrier frequency searching value of the corresponding real-time carrier frequency is the carrier frequency estimated value of the radiation source. In fig. 13, the cost function results are maximized when the search carrier frequencies are around 2.4GHz, 2.7GHz, 3GHz, 3.45GHz, and 3.6GHz, respectively, which are close to the actual carrier frequencies of the radiation source of 2.3GHz, 2.6GHz, 2.9GHz, 3.2GHz, and 3.5 GHz. The method for positioning disclosed by the invention achieves rough estimation of the carrier frequency parameters of the target while positioning the target.
According to the simulation verification test disclosed by the invention, when the technical problem of positioning a single radiation source is faced by a person in the field, the position of the single radiation source can be positioned by utilizing the technical scheme disclosed by the invention only by arranging the single radiation source in the grid point.
Example two
The second embodiment of the invention provides a mutual ambiguity function mapping radiation source positioning system based on carrier frequency searching, which comprises:
the grid point dividing module is used for dividing the target area of the radiation source into grid points, and generating a time-frequency difference lookup table through the time difference value and the frequency difference value of the radiation source signals corresponding to the grid points;
the searching carrier frequency determining module is used for determining the searching range and the searching step length of the searching carrier frequency of the radiation source signal and obtaining the initial carrier frequency of the searching carrier frequency according to the searching range;
the time-frequency difference range determining module is used for obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time-frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
the mutual fuzzy function value mapping module is used for taking a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual fuzzy function model, obtaining a mutual fuzzy function value through the mutual fuzzy function model, mapping the mutual fuzzy function value onto grid points, and forming a distribution diagram on the grid points;
the carrier frequency searching module is used for obtaining a real-time carrier frequency in a searching range according to the initial carrier frequency and the searching step length, updating the initial carrier frequency of the searching carrier frequency into the real-time carrier frequency, and re-calling the time frequency difference range determining module until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all the mapped mutual fuzzy function values;
the radiation source positioning module is used for obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; and meanwhile, the position coordinates of the radiation source are obtained through the peak value coordinate positioning in the distribution diagram.
Details of a carrier frequency search-based mutual ambiguity function mapping radiation source positioning system refer to details of a carrier frequency search-based mutual ambiguity function mapping radiation source positioning system method, which are not described herein.
The embodiment of the invention has the beneficial effects that:
the invention increases the carrier frequency searching and accumulating positioning process:
1. the sampling signal is directly used as calculation input without measuring signal parameters, so that the precision loss of intermediate parameter estimation is avoided;
2. the radiation source can be positioned without carrying out carrier frequency estimation on the signals independently in carrier frequency searching and accumulated positioning modes;
3. the method has the advantages that the target positioning and the target signal carrier frequency estimation are simultaneously carried out in the carrier frequency searching and accumulated positioning modes, and a reference is provided for subsequent signal sorting processing.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. A method for positioning a radiation source based on carrier frequency search and mutual ambiguity function mapping is characterized by comprising the following steps:
dividing a grid point for a radiation source target area, and generating a time-frequency difference lookup table through a time difference value and a frequency difference value of a radiation source signal corresponding to the grid point;
step two, determining a searching range and a searching step length of a searching carrier frequency of the radiation source signal, and obtaining an initial carrier frequency of the searching carrier frequency according to the searching range;
thirdly, obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
step four, using a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual blurring function model, obtaining a mutual blurring function value through the mutual blurring function model, mapping the mutual blurring function value onto grid points, and forming a distribution diagram on the grid points; the mutual ambiguity function model is as follows:
wherein CAF (τ, f d ) Is a mutual blurring function model; receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Time difference values of (2); f (f) d For receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Frequency difference value of (2); t is the total duration of receiving the radiation source signal; r is (r) 1 (t) receiving a time domain sample of the radiation source signal for the first receiver; r is (r) 2 (t+τ) is the second receiver of the time difference τReceiving a radiation source signal time domain sampling result;a second receiver which is the time difference value tau receives conjugation of the time domain sampling result of the radiation source signal; t is a sampling time point; e is a natural constant; j is the sign of the imaginary number;
step five, obtaining a real-time carrier frequency in a searching range according to the initial carrier frequency and the searching step length, updating the initial carrier frequency of the searching carrier frequency into the real-time carrier frequency, returning to the step three until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all mapped mutual fuzzy function values;
step six, obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; and meanwhile, the position coordinates of the radiation source are obtained through the peak value coordinate positioning in the distribution diagram.
2. The method of claim 1, wherein in step one, dividing the radiation source target area into grid points, and generating the time-frequency difference lookup table by the time-difference value and the frequency-difference value of the radiation source signal corresponding to the grid points comprises:
presetting a corresponding number of radiation source target area positioning coverage areas according to target radiation source positioning task requirements; grid division is carried out on a preset positioning coverage range of a radiation source target area to obtain a grid point set and a geographic coordinate set corresponding to the grid point set;
according to the geometric distribution relation between at least two receivers and the grid point set, calculating the time difference value and the frequency difference value of the arrival of the radiation source signals received by at least two receivers corresponding to each grid point through the geographic coordinate set corresponding to the grid point set, and generating a time-frequency difference lookup table uniquely corresponding to the radiation source signals and the grid points based on the time difference value and the frequency difference value.
3. The method of claim 1, wherein in the second step, a search range and a search step of a search carrier frequency of the radiation source signal are determined, and the method of obtaining an initial carrier frequency of the search carrier frequency according to the search range comprises:
determining a bandwidth range of a receiver receiving the radiation source signal as a search range of a search carrier frequency of the radiation source signal, and setting a minimum value of the search range as an initial carrier frequency of the search carrier frequency;
the search step length of the search carrier frequency of the radiation source signal is determined according to the precision requirement of the carrier frequency estimation.
4. The method of claim 1, wherein in the third step, in the search range, a time difference value corresponding to an initial carrier frequency of the search carrier frequency is obtained according to a time-frequency difference lookup table, and the time difference values are summarized to obtain a time difference table; the method for obtaining the frequency difference table by summarizing the frequency difference values according to the frequency difference lookup table to obtain the frequency difference value corresponding to the initial carrier frequency of the search carrier frequency comprises the following steps:
obtaining the distance difference between at least two receivers receiving the initial carrier frequency of the search carrier frequency and the grid point in the search range according to the time-frequency difference lookup table, obtaining the time difference value from the grid point to at least two receivers by using the calculation method of the distance difference/the light speed, namely obtaining the time difference value corresponding to the initial carrier frequency of the search carrier frequency, and summarizing the time difference value to obtain a time difference table;
in the searching range, according to the time-frequency difference lookup table, obtaining the radial speed difference between at least two receivers receiving the initial carrier frequency of the searching carrier frequency and the grid point, and using the speed difference multiplied by the operation method of searching carrier frequency/light speed to obtain the difference between the Doppler frequencies of the grid point relative to at least two receivers, namely obtaining the frequency difference value corresponding to the initial carrier frequency of the searching carrier frequency, and summarizing the frequency difference values to obtain the frequency difference table.
5. The method of claim 1, wherein in step three, the method of determining the time-frequency difference range by the time difference table and the frequency difference table comprises:
obtaining a time difference range represented by the maximum time difference value and the minimum time difference value according to the time difference table;
obtaining a frequency difference range represented by the maximum frequency difference value and the minimum frequency difference value according to the frequency difference table;
and setting an error range to obtain a time-frequency difference range of the coverage time-frequency difference lookup table, wherein the time-difference range comprises the error range and the frequency-frequency difference range comprises the error range.
6. The method of claim 1, wherein in step four, the step of mapping the mutual blur function values onto grid points, the step of forming a profile on grid points comprises:
corresponding the time difference coordinates of the mutual ambiguity function values to grid point time difference values;
corresponding the frequency difference coordinates of the mutual ambiguity function values to the grid point frequency difference values;
and then, the grid points are corresponding to the mutual fuzzy function values, and a distribution diagram of the mutual fuzzy function values on the grid points is obtained.
7. The method of claim 1, wherein in the fifth step, in the search range, a real-time carrier frequency is obtained according to the initial carrier frequency and the search step length, the initial carrier frequency of the search carrier frequency is updated to the real-time carrier frequency, the third step is returned until the real-time carrier frequency of the search carrier frequency is updated to the maximum value of the search range, and the method for completing carrier frequency search and accumulating all the mapped mutual ambiguity function values comprises:
in the searching range, adding the initial carrier frequency and the searching step length to obtain a real-time carrier frequency, replacing the initial carrier frequency of the searching carrier frequency with the real-time carrier frequency, updating the searching carrier frequency, and returning to the step three;
obtaining a time difference value corresponding to the real-time carrier frequency of the search carrier frequency according to the time frequency difference lookup table, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the real-time carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
using a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual blurring function model, obtaining a mutual blurring function value through the mutual blurring function model, and mapping the mutual blurring function value to a previous distribution diagram;
each mapping is accumulated on the basis of the original distribution diagram until the searching carrier frequency is updated to the maximum value of the searching range, carrier frequency searching is completed, and the mutual ambiguity function values of all the mappings are accumulated.
8. The method of claim 1, wherein in step six, carrier frequency estimates of the radiation source are obtained based on the distribution of the accumulated mapped mutually ambiguous function values at the grid points; the method for obtaining the position coordinates of the radiation source through peak coordinate positioning in the distribution diagram comprises the following steps:
obtaining a maximum mutual blur function value in a distribution diagram according to the distribution diagram of the accumulated mapped mutual blur function values on grid points, wherein the real-time carrier frequency corresponding to the maximum mutual blur function value is a carrier frequency estimated value of the radiation source;
and extracting the peak coordinates in the distribution diagram to obtain the position coordinates of the target radiation source.
9. A carrier frequency search based mutual ambiguity function mapping radiation source positioning system, comprising:
the grid point dividing module is used for dividing the target area of the radiation source into grid points, and generating a time-frequency difference lookup table through the time difference value and the frequency difference value of the radiation source signals corresponding to the grid points;
the searching carrier frequency determining module is used for determining the searching range and the searching step length of the searching carrier frequency of the radiation source signal and obtaining the initial carrier frequency of the searching carrier frequency according to the searching range;
the time-frequency difference range determining module is used for obtaining a time difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time-frequency difference lookup table in the search range, and summarizing the time difference value to obtain a time difference table; obtaining a frequency difference value corresponding to the initial carrier frequency of the search carrier frequency according to the time frequency difference lookup table, summarizing the frequency difference value to obtain a frequency difference table, and determining a time frequency difference range through the time difference table and the frequency difference table;
the mutual fuzzy function value mapping module is used for taking a time difference value and a frequency difference value in a time-frequency difference range as input of a mutual fuzzy function model, obtaining a mutual fuzzy function value through the mutual fuzzy function model, mapping the mutual fuzzy function value onto grid points, and forming a distribution diagram on the grid points; the mutual ambiguity function model is as follows:
wherein CAF (τ, f d ) Is a mutual blurring function model; receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Time difference values of (2); f (f) d For receiving radiation source signal r by second receiver in time-frequency difference range 2 Receiving a radiation source signal r relative to a first receiver 1 Frequency difference value of (2); t is the total duration of receiving the radiation source signal; r is (r) 1 (t) receiving a time domain sample of the radiation source signal for the first receiver; r is (r) 2 (t+τ) is the time-domain sampling result of the radiation source signal received by the second receiver with the time difference value τ;a second receiver which is the time difference value tau receives conjugation of the time domain sampling result of the radiation source signal; t is a sampling time point; e is a natural constant; j is the sign of the imaginary number;
the carrier frequency searching module is used for obtaining a real-time carrier frequency in a searching range according to the initial carrier frequency and the searching step length, updating the initial carrier frequency of the searching carrier frequency into the real-time carrier frequency, and re-calling the time frequency difference range determining module until the real-time carrier frequency of the searching carrier frequency is updated to the maximum value of the searching range, completing carrier frequency searching and accumulating all the mapped mutual fuzzy function values;
the radiation source positioning module is used for obtaining a carrier frequency estimated value of the radiation source according to the distribution diagram of the accumulated mapped mutual fuzzy function values on the grid points; and meanwhile, the position coordinates of the radiation source are obtained through the peak value coordinate positioning in the distribution diagram.
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