CN114442034A - Positioning method and device based on hyperbolic TDOA and computer readable storage medium - Google Patents
Positioning method and device based on hyperbolic TDOA and computer readable storage medium Download PDFInfo
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Abstract
The invention relates to the technical field of communication, and discloses a positioning method, a positioning device and a computer readable storage medium based on hyperbolic TDOA, wherein the method comprises the following steps: the system acquires the signal receiving time difference between a first receiver and a second receiver, and the signal receiving time difference is a first TDOA value; improving the accuracy of the first TDOA value by quadratic linear difference and polynomial fitting; calculating to obtain a first hyperbolic curve according to the first TDOA value with improved precision; changing the positions of the first receiver or/and the second receiver, and calculating to obtain a second hyperbolic curve; and calculating the positioning of the signal source according to the intersection point of the first hyperbola and the second hyperbola. According to the method, the precision of the obtained TDOA value is improved through the quadratic linear difference value and polynomial fitting, and then the position of a high-precision signal source can be calculated based on the TDOA value.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a hyperbolic TDOA-based positioning method, apparatus, and computer-readable storage medium.
Background
With the rapid development of wireless network and internet of things technology, the interconnection of everything is no longer far away. How to accurately locate the position of a person or an object is the most fundamental problem for realizing the interconnection of everything, so that the wireless location technology plays an especially important role therein. The wireless positioning technology has very wide application prospect in both military and life.
In wireless positioning, it is particularly important to search the position of a Signal source, and conventional wireless positioning methods mainly include a method based on Received Signal Strength (RSSI), a method based on Time of Arrival (TOA), and a method based on Angle of Arrival (AOA). The observation quantities are needed for positioning, and the signal source can be positioned after the observation quantities are calculated and analyzed through a specific algorithm.
However, with the RSSI wireless positioning processing scheme, when the signal passes through a wall or other large obstacles, additional signal attenuation is caused, and the RSSI is susceptible to severe fluctuation caused by multipath, so that the positioning accuracy is not good; for the TOA wireless positioning processing scheme, the clock between the transmitting end and the receiving end is required to be highly synchronous, so that the TOA wireless positioning processing scheme has higher requirements on hardware and is very difficult to realize; for the AOA wireless positioning processing scheme, the required array is generally expensive, very heavy and not easy to realize, the positioning accuracy mainly depends on the obtained AOA accuracy, and a smaller AOA error may cause a larger positioning accuracy error; for the TDOA wireless location processing scheme, the time differences between the signals transmitted from the signal source to the receiver pairs are measured by a plurality of receivers (paired in pairs), and when the positions of the receiver pairs are known, the positions of the signal source can be estimated by the time differences.
Disclosure of Invention
The invention mainly aims to solve the technical problem of low positioning precision in the existing positioning method.
The invention provides a positioning method based on hyperbolic TDOA in a first aspect, which comprises the following steps:
the system acquires the signal receiving time difference between a first receiver and a second receiver, and the signal receiving time difference is a first TDOA value;
improving the accuracy of the first TDOA value by a quadratic linear difference;
improving the accuracy of the first TDOA value by polynomial fitting;
calculating to obtain a first hyperbolic curve according to the first TDOA value with improved precision;
changing the positions of the first receiver or/and the second receiver, and calculating to obtain a second hyperbolic curve;
and calculating the positioning of the signal source according to the intersection point of the first hyperbola and the second hyperbola.
Optionally, the acquiring, by the system, a signal reception time difference between the first receiver and the second receiver, and the obtaining, as the first TDOA value, includes:
the signal sent by the signal source is s (t), and the signals received by the first receiver and the second receiver are x (t), y (t):
wherein n is1(t)，n2(t) is the noise interference in the channel transmission process, A is the amplitude of y (t) after amplitude normalization, t1For the value of the time delay at which the signal arrives at the first receiver, t2The first TDOA value is a time delay value of the signal arriving at the second receiver: d ═ t2-t1；
The system obtains the first TDOA value through correlation processing between the received signals of the first receiver and the second receiver, wherein the correlation processing comprises the following steps:
assuming that the system has limited time in the signal collection sampling process and the data obtained by AD sampling is discrete, after sampling, the signals received by the first receiver and the second receiver are respectively:
wherein, N is the number of sampling points of the signal in time T, D is the sampling point where the first TDOA value is located, and then the two signals are processed in a cross-correlation manner to obtain a cross-correlation function:
wherein R isss(n-D) is the cross-correlation between source signals,
for the cross-correlation between the noises, the position where the cross-correlation function takes the maximum value is the position where the first TDOA value is located;
the higher the rate of the AD sampling, the smaller the sampling interval, so that the higher the accuracy of the first TDOA value, the calculation formula is: t is ts＝n*T。
Optionally, the increasing the accuracy of the first TDOA value by a quadratic linear difference includes:
the data obtained by AD sampling is discrete, a straight line is drawn by taking two adjacent points in the sampling points as a reference, and other values between the two points are replaced by values on the straight line:
(I0，A0) And (I)1，A1) As original sampling points, the empty points are assumed interpolated values, where the equation corresponding to the straight line is: kt- (kI)1-A1)
Wherein the content of the first and second substances,
the slope of the line, the value of the empty point to be inserted is estimated according to this equation,
inserting N values between two points of the original sample data, the number of original sample data becomes: m is Na+N(Na-1)，
The total time of sampling is unchanged, and the sampling interval after interpolation is:
wherein, TaIs the total time of sampling, NaMuch greater than N, by at least one order of magnitude, T0The sampling interval is the original sampling interval,
the original sampling rate is calculated to become: fs＝(N+1)F0In which F is0And increasing the original sampling rate to be N +1 times, and increasing the precision of the first TDOA value to be N +1 times.
Optionally, the improving the accuracy of the first TDOA value by polynomial fitting includes:
the polynomial fitting includes: constructing a function y ═ f (x), and approximating the function to an original function g (x) in an infinite manner so that the deviation δ ═ Σ | f (x) -g (x) is equal to ∑ f (x)i) (i-1, 2, 3 … N) is minimal, in that process f (x) is not required to pass through all points, but is simply brought as close as possible to them;
after obtaining f (x) by polynomial fitting, calculating function point (x) corresponding to maximum value of f (x)a，ya) And inserting N number between two points during secondary interpolation, and equating the sampling interval to the original 1/N to obtain a first TDOA value with improved precision: t is tr＝(xa-300)*Ta/N。
Optionally, the improving the accuracy of the first TDOA value by polynomial fitting includes:
the polynomial fitting includes: assuming that n sampling points are provided, a polynomial of m times (m < n) is constructed in the following construction mode: f (x) ═ a0+a1x1+a2x2+…+amxm，
When calculating the function fitting function, the calculation is performed by using a least square method, as shown in the following equation:
find f (x) that minimizes ε,
after f (x) is obtained by polynomial fitting, the function point (x) corresponding to the maximum value of f (x) is calculateda，ya) During secondary interpolation, 100 samples are inserted between two points, the sampling interval is equivalent to the original 1/100, and the first TDOA value with improved precision is obtained: t is tr＝(xa-300)*Ta/100。
Optionally, the obtaining a first hyperbolic curve by calculating according to the first TDOA value with improved accuracy includes:
the system calculates a distance difference between the signal source and the first receiver and the second receiver, and the distance difference is expressed by the following formula: rd＝c*td，
Wherein R isdC is the propagation speed of electromagnetic wave in space, t is the distance difference between the signal source and the first receiver and the second receiverdThe first TDOA value after the precision is improved;
a first hyperbola is calculated:
wherein (x)1，y1) Is the position of the first receiver, (x)2，y2) Is the location of the second receiver.
Optionally, the changing the position of the first receiver or/and the second receiver, and calculating a second hyperbolic curve includes:
changing the position of the first receiver or/and the second receiver;
the system acquires the signal receiving time difference between a first receiver and a second receiver, and the signal receiving time difference is a second TDOA value;
improving the accuracy of the second TDOA value by a quadratic linear difference;
improving the accuracy of the second TDOA value by polynomial fitting;
and calculating to obtain a second hyperbolic curve according to the second TDOA value after the precision is improved.
Optionally, the acquiring, by the system, a signal reception time difference between the first receiver and the second receiver, and the first TDOA value includes:
the system carries out multiple data acquisition measurements to obtain multiple corresponding first TDOA values;
discarding first TDOA values that meet an outlier determination condition among the plurality of first TDOA values;
and averaging the rest first TDOA values to obtain the first TDOA value.
A second aspect of the present invention provides a hyperbolic TDOA-based positioning apparatus, comprising:
the acquisition module is used for acquiring the signal receiving time difference between the first receiver and the second receiver, and the signal receiving time difference is a first TDOA value;
a precision improving module for improving the precision of the first TDOA value through a quadratic linear difference value and improving the precision of the first TDOA value through polynomial fitting;
and the calculating module is used for calculating to obtain a first hyperbolic curve according to the first TDOA value after the precision is improved, calculating a second hyperbolic curve and calculating the positioning of the signal source according to the intersection point of the first hyperbolic curve and the second hyperbolic curve.
A third aspect of the present invention provides a computer-readable storage medium having stored therein instructions, which, when run on a computer, cause the computer to perform the hyperbolic TDOA-based positioning method described above.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a positioning method, which is characterized in that after TDOA values of two receivers are obtained, precision of the TDOA values is improved through quadratic linear difference values and polynomial fitting, so that the precision of the TDOA values is obviously improved, and then when the position of a signal source is calculated based on the TDOA values, the position of a high-precision signal source can be calculated. In addition, the position of two receivers is changed, so that the effect of detecting positioning by a plurality of receivers is achieved.
Drawings
FIG. 1 is a flowchart illustrating a hyperbolic TDOA-based positioning method according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating a scenario of hyperbolic positioning processing according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a scenario of precision enhancement processing based on quadratic linear difference according to an embodiment of the present invention;
FIG. 4 is a schematic view of a scenario of a hyperbolic TDOA-based positioning method according to the present invention;
FIG. 5 is a schematic diagram of an embodiment of a hyperbolic TDOA-based positioning device of the present invention.
Detailed Description
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Before describing the hyperbolic TDOA-based positioning method provided by the present invention, the background of the present invention will be described.
The hyperbolic TDOA-based positioning method, the hyperbolic TDOA-based positioning device and the computer-readable storage medium provided by the invention can be applied to a positioning system of a signal source, and are used for performing precision improvement processing on the obtained TDOA value through quadratic linear difference and polynomial fitting in a TDOA wireless positioning processing scheme, so that the position of the high-precision signal source can be calculated based on the TDOA value.
TDOA location refers to the measurement of the time difference between the signal transmitted from a signal source to a pair of receivers by a plurality of receivers (paired pairwise), respectively, and the position of the signal source can be estimated from these time differences when the positions of the pair of receivers are known. Conventional TDOA location methods typically use three or more receivers to locate the signal source, where the measured TDOA value between each two receivers corresponds to a hyperbola/plane, and the intersection of the different hyperbolas/planes is the location of the signal source.
The hyperbolic TDOA-based positioning method provided by the invention can be implemented by a positioning device of a signal source or a positioning system of the signal source of the positioning device integrated with the signal source. The positioning device of the signal source may be implemented in a hardware or software manner, the positioning system of the signal source may be set in a device cluster manner, the devices related to the system may be different types such as a server, a physical host, or a User Equipment (UE), and the UE may be a terminal device such as a smart phone, a tablet computer, a notebook computer, a desktop computer, or a Personal Digital Assistant (PDA).
In addition, the positioning system based on the hyperbolic TDOA can be combined with a receiver or even a signal source outside the system to cooperate to determine the position of the signal source, and the receiver or even the signal source can be directly included in the system and can be specifically adjusted according to specific application scenarios.
The embodiment of the invention provides a positioning method and device based on hyperbolic TDOA and a computer readable storage medium.
For the sake of understanding, the following detailed description of the embodiments of the present invention refers to fig. 1, and an embodiment of the hyperbolic TDOA-based positioning method in the embodiments of the present invention includes:
101. the system obtains the signal receiving time difference of the first receiver and the second receiver as the first TDOA value
The first TDOA value is a time delay value between the point in time of reception of the signal emitted by the signal source by the first receiver and the second receiver. The calculation of the first TDOA delay value includes two methods, one is to obtain the first TDOA value by directly subtracting the measured TOA values, and the other is to obtain the first TDOA value by correlating the two received signals.
102. Increasing the accuracy of the first TDOA value by a quadratic linear difference
The accuracy of the first TDOA value is related to the sampling rate of the signal. The sampling rate of the signal is the rate of AD sampling on the receiving device, and the general AD sampling rate is not high, so that the AD sampling rate can be increased by a quadratic linear difference method, and the accuracy of the first TDOA value is further improved.
103. Improving accuracy of first TDOA values by polynomial fitting
Polynomial fitting is a method that is commonly used mathematically to construct a fitting function using a plurality of points in order to minimize the deviation of the fitting function from these points. By constructing the function y (f) (x) and approximating it infinitely to the original function g (x) such that its deviation δ ∑ i f (x) -g (xi) i (i ═ 1, 2, 3 … N) is minimal, it is not necessary for f (x) to pass through all points, but rather to be as close as possible to them.
104. Calculating to obtain a first hyperbolic curve according to the first TDOA value after the precision is improved
After the first TDOA value which is more accurate is obtained, the distance difference between the signal source and the two receivers can be obtained, and according to the hyperbolic principle, the signal source is on a hyperbolic curve which takes the two receivers as focuses and the distance difference as a long axis, and then the first hyperbolic curve is obtained through calculation.
105. Changing the position of the first receiver or/and the second receiver to obtain a second hyperbola
The purpose that a plurality of receivers receive signals is achieved by changing the positions of the first receiver or the second receiver, signal collection and analysis are carried out again, the steps are repeated, and the system obtains the signal receiving time difference of the first receiver and the second receiver, namely a second TDOA value; improving the accuracy of the second TDOA value through quadratic linear difference and polynomial fitting; and calculating to obtain a second hyperbolic curve according to the second TDOA value with improved precision.
106. Calculating the location of the signal source from the intersection of the first hyperbola and the second hyperbola
As shown in fig. 2, the intersection point of the first hyperbola and the second hyperbola is the position of the signal source.
The positioning algorithm of the embodiment of the method is very simple, and the positioning precision mainly depends on the precision of the TDOA obtained through calculation. It can be understood that, in the application scenario of the TDOA wireless processing scheme, the positioning method provided in the embodiment of the present invention performs the calculation of the position of the corresponding signal source according to the conventional TDOA value, and in this process, the accuracy improvement processing is performed on the TDOA value, that is, between the input data and the output data, the accuracy of the intermediate parameter is improved, so that the output data with high accuracy can be output.
Specifically, in step S101, the acquired first TDOA value may be an existing TDOA value directly extracted from a local system or other devices, wherein the extracted TDOA value may also carry or configure related information, such as signal content, time point, device identification, and the like of the received signal. In addition, the TDOA in step S101 may be processed in real time by the system, or may be processed in a historical time period, and may be extracted when the method for positioning the signal source provided by the present invention is triggered.
Taking the first method as an example, the system processes the first TDOA value in real time, and as a practical implementation, a direct measurement method may be adopted, for example: the system acquires a receiving time point t1 of the first receiver for the signal sent by the signal source; the system acquires a receiving time point t2 of the second receiver for the signal sent by the signal source; the system determines the time delay value between the reception time t1 and the reception time t2 as the first TDOA value.
It can be seen that in this direct measurement mode, the TDOA value is directly used by taking the difference between the two signals, following the principle that the TDOA value is used as the time difference of arrival (time delay value) between the two signals received by the two receivers.
In addition, as another practical implementation manner, that is, the second method for calculating the first TDOA delay value, the first TDOA value may also be obtained by performing Correlation processing through Correlation between two received signals, for example, the embodiment of the present invention may specifically perform the processing by using a Generalized Cross Correlation (GCC), specifically:
suppose that the signal sent by the signal source is s (t), and the signals received by the two receivers are x (t), y (t):
wherein n is1(t)，n2(t) is the noise interference in the channel transmission process, A is the amplitude of y (t) after amplitude normalization, t1For the value of the time delay at which the signal arrives at the first receiver, t2The first TDOA value is a time delay value of the signal arriving at the second receiver:
d＝t2-t1 (2)
assuming that the time is limited during the signal collection and sampling process and the data obtained by AD (analog to Digital) sampling is discrete, the two signals after sampling are:
wherein, N is the number of sampling points of the signal in time T, D is the sampling point at which the first TDOA value is located, and the two signals are processed by cross-correlation:
wherein R isss(n-D) is the cross-correlation between source signals,
for the cross-correlation between the noise, the position at which the cross-correlation function takes the maximum value, is the position at which the TDOA value is located,
however, it can be known from equation (3) that the value of n can only be a positive integer, so the calculated first TDOA value can only be an integer multiple of the sampling interval T, so the accuracy of the TDOA value has a close relationship with the rate of AD sampling, and the higher the rate of AD sampling, the smaller the sampling interval, so that the higher the accuracy of the first TDOA value, the calculation formula is as follows:
ts＝n*T (5)
it can be seen that, in the process of acquiring the first TDOA value, the system may also improve the accuracy of the acquired initial first TDOA value by optimizing the acquisition manner.
Furthermore, simulation analysis of different modulation modes in a noisy environment can find that when two signals are subjected to cross-correlation operation, a peak point of a cross-correlation function may shift, and the actual peak value is deviated to another peak value, so that a rough time delay value may generate a great error which may reach hundreds of nanoseconds, so that the time delay value is not credible and cannot be used for positioning,
in order to solve the problem of difficult positioning in a noisy environment, an embodiment of the present invention further provides a solution for removing outliers through multiple measurements, where the system includes, in the process of calculating the first TDOA value: the system carries out data acquisition and measurement for multiple times to obtain a plurality of corresponding first TDOA values; discarding the first TDOA values meeting the outlier determination condition from the plurality of first TDOA values; and averaging the rest first TDOA values to obtain the first TDOA value.
Through outlier judgment processing and mean value processing, a very accurate first TDOA value can be guaranteed, since the signal-to-noise ratio is basically over 10dB on a designed hardware platform, and when the signal-to-noise ratio is 10dB, the outlier probability of an algorithm is far less than 50% and is only 13.3%, the outlier elimination processing is easily realized, and averaging is performed, so that the result is more integrated, the accuracy of the calculated first TDOA value is higher, and the problem of noise interference on the signal source positioning can be effectively solved.
After the initial first TODA value is obtained, the initial first TDOA value may also be affected by the AD sampling rate at the receiver (the AD sampling rate is generally not high), which results in that the accuracy of the calculated first TDOA value is not high, that is, a problem of the existing TDOA wireless positioning scheme, for which, the embodiment performs further accuracy improvement processing by step S102.
Specifically, in step S102, referring to a scene diagram of the accuracy improvement processing based on the quadratic linear difference value of the present invention shown in fig. 3, a straight line is drawn with two adjacent points of the discrete points as references, and the other values between the two points are replaced by the values on the straight line:
two solid points (I)0，A0) And (I)1，A1) For the original sample point, the empty point is the value assumed to be inserted, where the equation corresponding to the straight line is:
y＝kt-(kI1-A1) (6)
wherein the content of the first and second substances,
the slope of the line, the value of the empty point to be inserted is estimated according to this formula,
assuming that N values need to be inserted between two points of the original sample data, the number of the original sample data is:
M＝Na+N(Na-1) (7)
but the total time of sampling is not changed, only the data length is changed, and the sampling interval after interpolation can be expressed as follows:
wherein, TaIs the total time of sampling, since in general N isaMuch larger than N, by at least one order of magnitude, which is equivalent to:
wherein, T0And finally, changing the original sampling rate into an equivalent value as follows:
Fs＝(N+1)F0 (10)
it can be found that, for the initial TDOA value obtained in step S101, the accuracy thereof is relatively rough, but the accuracy thereof can be significantly improved after the accuracy improvement processing of the quadratic linear difference and the polynomial fitting is introduced in the present invention.
Among them, for the precision improvement processing of the performed quadratic linear difference, the present invention considers that N is not as large as possible, because it is limited by the magnitude of the actual delay of the two signals, the signal noise, and the AD sampling rate.
Therefore, the present invention continues to incorporate a process for accuracy improvement of polynomial fitting, a method for constructing a fitting function using a plurality of points, with the objective of minimizing the deviation between the fitting function and these points, and improving the accuracy of the first TDOA value.
Specifically, in step S103, the function y ═ f (x) is constructed, and infinitely approximated to the original function g (x), and the deviation δ ═ Σ | f (x) -g (x) is seti) I (i-1, 2, 3 … N) is minimal, and it is not required in this process that f (x) pass through all points, but as close as possible to them.
Assuming n sampling points, a polynomial of degree m (m < n) is constructed in the following way:
f(x)＝a0+a1x1+a2x2+…+amxm (11)
in calculating the fitting function, the fitting function is calculated by using a least square method, as shown in the following formula:
bringing formula (11) into formula (12), obtaining f (x) that minimizes ε,
when calculating TDOA value, after quadratic interpolation and polynomial fitting to obtain f (x), finding function point (x) corresponding to maximum valuea，ya) This function point can be called as a fine peak point of the cross-correlation function because 100 numbers of the function points are inserted between the two points during the quadratic interpolation, where N is much larger than N, and the sampling interval is equivalent to the original one as can be seen from equation (8)1/100, calculating a fine delay value as:
tr＝(xa-300)*Ta/100 (13)
through tests, the method can improve the precision of the TDOA value to ns level after improving the precision of the TDOA value in a soft mode and in a mode of combining quadratic linear interpolation and polynomial fitting.
Specifically, in step S104, the system finds a distance difference between the signal source and two receivers, and the distance difference is expressed as follows:
Rd＝c*td (14)
wherein R isdC is the propagation speed of electromagnetic wave in space, assumed as the speed of light, tdTo calculate the first TDOA value after the precision improvement process,
according to the hyperbolic principle, a signal source is on a hyperbolic curve which takes two receivers as focuses and takes a distance difference as a long axis, and the specific formula is as follows:
wherein (x)1，y1) Is the position of the first receiver, (x)2，y2) Is the location of the second receiver.
In step S105 and step S106, after the positions of the two receivers are changed (which may be triggered by the system, the change processing of the positions is performed, or the change of the positions of the receivers is monitored), the system performs signal acquisition and analysis again, and re-determines the position of another hyperbola, where the intersection point of the two hyperbolas is the location of the signal source.
In order to facilitate understanding of the calculation processing of the signal source herein, it can be understood by combining with a scenario diagram of the hyperbolic positioning processing of the present invention shown in fig. 4, and in practical operation, it is found that the positioning processing is very simple, the positioning accuracy thereof mainly depends on the accuracy of the calculated previous TDOA value, the higher the accuracy of the previous TDOA value is, the higher the positioning accuracy of the algorithm is, and if a very accurate TDOA value can be obtained, the positioning error of the algorithm can be even ignored.
After the accuracy of the previous TDOA value (obtained in step S101) is significantly improved by the signal source positioning method provided by the present invention, in practical application, the position of the signal source can be accurately located only by one set of TDOA values (only two receivers), so as to achieve the effect of detecting and positioning by multiple receivers in the TDOA wireless positioning scheme in the prior art.
Through tests, the position of the signal source is determined through the TDOA value after precision improvement processing, and the error precision of the positioning signal source is about meter level.
For the convenience of understanding, the above description can be further understood with reference to a scene schematic diagram of the signal source positioning method of the present invention shown in fig. 4.
After determining the location of the signal source, the system may then output the location of the signal source, e.g., for display on a display screen, for transmission to other devices to provide for use of the data, etc.
Or, the system can also perform corresponding data processing according to the data use requirement in the system based on the position of the signal source.
As another practical implementation, after obtaining the location of the signal source, the signal source can be further converted into a location position adapted to the use platform according to the use requirement, that is: the system determines a localized position of the signal source on the platform based on the position of the signal source and the localized position range on the platform.
It can be understood that, in the related platform using the location position, the location position that can be displayed or used by the user can be adjusted to a certain extent (i.e. the location position range on the platform) according to the use requirement of the user, the operation requirement of the platform, or even the requirement of the related policy, so that after the system background calculates the position of the signal source according to the TDOA value, the position can be adjusted to the location position adapted to the platform in the operation process, thereby ensuring good practicability.
The foregoing is an introduction to the hyperbolic TDOA-based positioning method, and in order to better implement the hyperbolic TDOA-based positioning method provided in the present invention, the present invention further provides a hyperbolic TDOA-based positioning apparatus from a functional block perspective.
Referring to fig. 5, fig. 5 is a schematic structural diagram of an embodiment of a location apparatus based on hyperbolic TDOA according to the present invention, in the embodiment, the location apparatus 500 based on hyperbolic TDOA specifically includes the following structures:
an obtaining module 501, configured to obtain a signal receiving time difference between a first receiver and a second receiver, where the signal receiving time difference is a first TDOA value;
a precision increasing module 502 for increasing the precision of the first TDOA value by a quadratic linear difference and by polynomial fitting;
a calculating module 503, configured to calculate a first hyperbolic curve according to the first TDOA value with improved accuracy, calculate a second hyperbolic curve, and calculate a location of the signal source according to an intersection point of the first hyperbolic curve and the second hyperbolic curve.
In yet another exemplary implementation, the apparatus further includes an output module 504 configured to:
outputting a location of the signal source;
alternatively, the apparatus further comprises a processing module 505 for:
and carrying out corresponding data processing based on the position of the signal source.
In another exemplary implementation manner, the processing module 505 is specifically configured to:
and determining the positioning position of the signal source on the platform based on the position of the signal source and the positioning position range on the platform.
It is clear to those skilled in the art that, for convenience and brevity of description, the detailed working process of the positioning apparatus based on hyperbolic TDOA and the corresponding modules thereof described above may refer to the description of the positioning method based on hyperbolic TDOA in the corresponding embodiment of fig. 1, and detailed description thereof is omitted here.
It will be understood by those skilled in the art that all or part of the steps of the methods of the above embodiments may be performed by instructions or by associated hardware controlled by the instructions, which may be stored in a computer readable storage medium and loaded and executed by a processor.
For this reason, the present invention provides a computer-readable storage medium, wherein a plurality of instructions are stored, and the instructions can be loaded by a processor to execute the steps of the hyperbolic TDOA-based positioning method in the embodiment corresponding to fig. 1 of the present invention, and specific operations can refer to the description of the hyperbolic TDOA-based positioning method in the embodiment corresponding to fig. 1, and are not repeated herein.
Wherein the computer-readable storage medium may include: read Only Memory (ROM), Random Access Memory (RAM), magnetic or optical disks, and the like.
Since the instructions stored in the computer-readable storage medium can execute the steps of the hyperbolic TDOA-based positioning method in the embodiment corresponding to fig. 1, the advantageous effects that can be achieved by the hyperbolic TDOA-based positioning method in the embodiment corresponding to fig. 1 can be achieved, which are described in detail in the foregoing description and are not repeated herein.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A hyperbolic TDOA-based positioning method, characterized in that the positioning method comprises:
the system acquires the signal receiving time difference between a first receiver and a second receiver, and the signal receiving time difference is a first TDOA value;
improving the accuracy of the first TDOA value by a quadratic linear difference;
improving the accuracy of the first TDOA value by polynomial fitting;
calculating to obtain a first hyperbolic curve according to the first TDOA value with improved precision;
changing the positions of the first receiver or/and the second receiver, and calculating to obtain a second hyperbolic curve;
and calculating the positioning of the signal source according to the intersection point of the first hyperbola and the second hyperbola.
2. The hyperbolic TDOA-based positioning method of claim 1, wherein said system obtaining the time difference between the first and second receiver signal receptions as a first TDOA value comprises:
the signal sent by the signal source is s (t), and the signals received by the first receiver and the second receiver are x (t), y (t):
wherein n is1(t)，n2(t) is the noise interference in the channel transmission process, A is the amplitude of y (t) after amplitude normalization, t1For the value of the time delay at which the signal arrives at the first receiver, t2The first TDOA value is a time delay value of the signal arriving at the second receiver: d ═ t2-t1；
The system obtains the first TDOA value through correlation processing between the received signals of the first receiver and the second receiver, wherein the correlation processing comprises the following steps:
assuming that the system has limited time in the signal collection sampling process and the data obtained by AD sampling is discrete, after sampling, the signals received by the first receiver and the second receiver are respectively:
wherein, N is the number of sampling points of the signal in time T, D is the sampling point where the first TDOA value is located, and then the two signals are processed in a cross-correlation manner to obtain a cross-correlation function:
wherein R isss(n-D) is the cross-correlation between source signals,
for the cross-correlation between the noises, the position where the cross-correlation function takes the maximum value is the position where the first TDOA value is located;
the higher the rate of the AD sampling, the smaller the sampling interval, so that the higher the accuracy of the first TDOA value, the calculation formula is: t is ts＝n*T。
3. The hyperbolic TDOA-based positioning method of claim 1, wherein said improving the accuracy of said first TDOA value by a quadratic linear difference comprises:
the data obtained by AD sampling is discrete, a straight line is drawn by taking two adjacent points in the sampling points as a reference, and other values between the two points are replaced by values on the straight line:
(I0，A0) And (I)1，A1) As original sampling points, the empty points are assumed interpolated values, where the equation corresponding to the straight line is: kt- (kI)1-A1)
Wherein, the first and the second end of the pipe are connected with each other,
the slope of the line, the value of the empty point to be inserted is estimated according to this equation,
inserting N values between two points of the original sample data, the number of original sample data becomes: m is equal to Na+N(Na-1)，
The total time of sampling is not changed, and the sampling interval after interpolation is:
wherein, TaIs the total time of sampling, NaGreater than N by at least one order of magnitude, T0The sampling interval is the original sampling interval,
the original sampling rate is calculated to become: fs＝(N+1)F0In which F is0And increasing the original sampling rate to be N +1 times, and increasing the precision of the first TDOA value to be N +1 times.
4. The hyperbolic TDOA-based positioning method of claim 3, wherein said improving the accuracy of said first TDOA value by polynomial fitting comprises:
the polynomial fitting includes: constructing a function y ═ f (x), and approximating the function to an original function g (x) in an infinite manner so that the deviation δ ═ Σ | f (x) -g (x) is equal to ∑ f (x)i) (i-1, 2, 3 … N) is minimal, in that process f (x) is not required to pass through all points, but is simply brought as close as possible to them;
after f (x) is obtained by polynomial fitting, the function point (x) corresponding to the maximum value of f (x) is calculateda，ya) And inserting N number between two points during secondary interpolation, and equating the sampling interval to the original 1/N to obtain a first TDOA value with improved precision: t is tr＝(xa-300)*Ta/N。
5. The hyperbolic TDOA-based positioning method of claim 4, wherein said improving the accuracy of said first TDOA value by polynomial fitting comprises:
the polynomial fitting includes: assuming that n sampling points are provided, a polynomial of m times (m < n) is constructed in the following construction mode: f (x) ═ a0+a1x1+a2x2+…+amxm，
When calculating the function fitting function, the calculation is performed by using a least square method, as shown in the following equation:
find f (x) that minimizes ε,
after f (x) is obtained by polynomial fitting, the function point (x) corresponding to the maximum value of f (x) is calculateda，ya) During secondary interpolation, 100 samples are inserted between two points, the sampling interval is equivalent to the original 1/100, and the first TDOA value with improved precision is obtained: t is tr＝(xa-300)*Ta/100。
6. The hyperbolic TDOA-based positioning method of claim 1, wherein said calculating a first hyperbola from said first TDOA values with improved accuracy comprises:
the system calculates a distance difference between the signal source and the first receiver and the second receiver, and the distance difference is expressed by the following formula: rd＝c*td，
Wherein R isdC is the propagation speed of electromagnetic wave in space, t is the distance difference between the signal source and the first receiver and the second receiverdThe first TDOA value after the precision is improved;
a first hyperbola is calculated:
wherein (x)1，y1) Is the position of the first receiver, (x)2，y2) Is the location of the second receiver.
7. The hyperbolic TDOA-based positioning method of claim 1, wherein said varying the position of said first receiver or/and said second receiver to calculate a second hyperbola comprises:
changing the position of the first receiver or/and the second receiver;
the system acquires the signal receiving time difference between a first receiver and a second receiver, and the signal receiving time difference is a second TDOA value;
improving the accuracy of the second TDOA value by a quadratic linear difference value;
improving the accuracy of the second TDOA value by polynomial fitting;
and calculating to obtain a second hyperbolic curve according to the second TDOA value with improved precision.
8. The hyperbolic TDOA-based positioning method of claim 1, wherein said system obtaining the time difference between the first and second receiver signal receptions as a first TDOA value comprises:
the system carries out data acquisition and measurement for multiple times to obtain a plurality of corresponding first TDOA values;
discarding first TDOA values that meet an outlier determination condition among the plurality of first TDOA values;
and averaging the rest first TDOA values to obtain the first TDOA value.
9. A hyperbolic TDOA-based positioning device, comprising:
the acquisition module is used for acquiring the signal receiving time difference between the first receiver and the second receiver, and the signal receiving time difference is a first TDOA value;
a precision improving module for improving the precision of the first TDOA value through a quadratic linear difference value and improving the precision of the first TDOA value through polynomial fitting;
and the calculating module is used for calculating to obtain a first hyperbolic curve according to the first TDOA value after the precision is improved, calculating a second hyperbolic curve and calculating the positioning of the signal source according to the intersection point of the first hyperbolic curve and the second hyperbolic curve.
10. A computer readable storage medium having stored thereon instructions which, when executed by a processor, implement the hyperbolic TDOA-based location method of any one of claims 1-8.
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