KR101689628B1 - Apparatus and method for estimating passive emitter location - Google Patents

Apparatus and method for estimating passive emitter location Download PDF

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KR101689628B1
KR101689628B1 KR1020150108274A KR20150108274A KR101689628B1 KR 101689628 B1 KR101689628 B1 KR 101689628B1 KR 1020150108274 A KR1020150108274 A KR 1020150108274A KR 20150108274 A KR20150108274 A KR 20150108274A KR 101689628 B1 KR101689628 B1 KR 101689628B1
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doa
signal source
calculating
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value
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박영미
박진오
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국방과학연구소
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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
    • G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
    • G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves

Abstract

The present invention relates to an apparatus and a method for estimating a position of a fixed signal source in a mobile receiver environment. According to an embodiment of the present invention, the apparatus for estimating a position of a fixed signal source comprises: a direction of arrival (DOA) calculation unit for calculating a direction of arrival (DOA)_1 and a DOA_2 which are a candidate value of a DOA; an initial position calculation unit for calculating an X_0 (1) and an X_0 (2), which are an initial position value of the fixed signal source; a position estimation unit for calculating an x (1) and an x (2) which are a position estimation value of the fixed signal source, and g (1) and g (2) which are an absolute value of residual corresponding to each position estimation value by applying method of least squares to X_0 (1) and an X_0 (2), TDOA measured as time goes by, frequency difference of arrival (FDOA), DOA1 and DOA2; and a position calculation unit for calculating either the x (1) or the x (2) as a position of the fixed signal source based on the calculated g (1) and g (2).

Description

[0001] APPARATUS AND METHOD FOR ESTIMATING PASSIVE EMITTER LOCATION [0002]

The present invention relates to an apparatus and method for estimating the position of a fixed signal source in a mobile receiver environment.

In order to estimate the position of the signal source, information such as time difference of arrival (TDOA), frequency difference of arrival (FDOA), and direction of arrival (DOA) may be used.

However, in the field of passive emitter localization, there is a problem that it is difficult to precisely estimate the position of a remote signal source using a small number of receivers.

The present invention is directed to solving the above-mentioned problems and other problems.

Yet another object is to provide a method and apparatus for determining a LM (Levenberg-Berkeley) method, which is one of nonlinear least squares methods, based on continuous composite measurement information of time difference of arrival (TDOA), frequency difference of arrival (FDOA) and direction of arrival (DOA) It is an object of the present invention to provide an apparatus and method for estimating the position of a fixed signal source using a Marquardt algorithm.

According to one aspect of the present invention there is provided a method for determining a time difference of arrival (DOA) based on a time difference of arrival (TDOA) value for a first mobile receiver receiving a signal from a fixed signal source and a second mobile receiver, a DOA calculation unit for calculating DOA 1 and DOA 2, which are candidate values of the arrival of the vehicle;

The calculated DOA 1 And DOA 2 Based on the value and the maximum position estimation range of the reception of the first moving receiver and the second moving receiver, calculating the initial position for calculating the initial position value of x 0 (1) and x 0 (2) of the fixed signal source part;

By applying the calculation by x 0 (1) and x 0 (2), the value of the TDOA, FDOA (frequency difference of arrival), DOA 1 and DOA 2, measured according to the continuous time in a non-linear least square method, the fixing signal A position estimator for calculating g (1) and g (2), which are absolute values of residuals corresponding to the respective position estimation values, x (1) and x And

And a position calculating unit for calculating one of the x (1) and x (2) as the position of the fixed signal source based on the calculated values of g (1) and g (2) The present invention provides an apparatus for estimating the position of a fixed signal source.

In an embodiment, the position estimator may use an LM (Levenberg-Marquardt) algorithm with the nonlinear least squares method.

In an embodiment, the residual corresponding to each of the position estimate values means a degree of matching of the algorithm and values applied to the algorithm.

In the embodiment, the position calculation unit may calculate the position of the fixed signal source that the absolute value of the corresponding residual of x (1) and x (2) is smaller.

According to another aspect of the present invention,

(a) a DOA calculation unit configured to calculate a DOA (direction of arrival) candidate value (DOA) based on a time difference of arrival (TDOA) value for a first mobile receiver and a second mobile receiver that receive a signal from a fixed signal source, 1 and DOA 2 ;

(b) The initial position calculating unit calculates the DOA 1 And DOA 2 Calculating a value and the first moving receiver and the initial position value of x 0 (1) and x 0 (2) of the fixed signal source based on the maximum position estimation range by the reception sensitivity of the second mobile receiver;

(c) TDOA, frequency difference of arrival (FDOA), DOA 1 and DOA 2 values measured according to the calculated continuous x 0 (1) and x 0 (2) (1) and g (2), which are the absolute values of residuals corresponding to the respective estimated position values, are obtained by applying the least squares method to the position estimate values x (1) and x Calculating; And

(d) calculating one of the x (1) and x (2) as the position of the fixed signal source based on the calculated values of g (1) and g (2) The method of estimating a position of a stationary signal source according to the present invention includes the steps of:

In the embodiment, the step (c) may include using a LM (Levenberg-Marquardt) algorithm with the nonlinear least squares method.

In an embodiment, the residual corresponding to each of the position estimate values means a degree of matching of the algorithm and values applied to the algorithm.

In the embodiment, the step (d) may include calculating the absolute value of the corresponding residual of x (1) and x (2) to be smaller in the position of the fixed signal source .

According to the present invention, time difference of arrival (TDOA), frequency difference of arrival (FDOA), and direction of arrival (DOA) information excellent in the position estimation performance of a fixed signal source can be used in the operating environment of two moving receivers . Specifically, the position of the fixed signal source can be estimated with a small number of receivers based on the nonlinear least squares method.

In order to improve the stability of the LM (Levenberg-Marquardt) algorithm, which is one of the nonlinear least squares methods, the position of the initial signal source can be selected. As a result, the position of the stationary signal source can be stably estimated even with a small number of receivers.

Further scope of applicability of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, such as the preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

1 is a block diagram illustrating an apparatus for estimating a position of a fixed-signal source according to an embodiment of the present invention.
2 is a flowchart illustrating an embodiment of a method of estimating the position of a fixed signal source according to the present invention.
3 is a conceptual diagram for explaining the concept of direction detection using TDOA.
FIG. 4 is an example showing the ambiguity of the DOA of the fixed signal source generated according to the measured value of the TDOA.
5 is a conceptual diagram showing an embodiment in which the same TDOA value is measured in different orientations.
6 is a conceptual diagram showing an embodiment of the LM method.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the technical idea of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly explain the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

First, the principle of an apparatus and method for estimating the position of a fixed signal source according to the present invention will be described.

In the present invention, a realistic algorithm for performing position estimation using TDOA, FDOA, and DOA information having the smallest theoretical positioning error lower limit (CRLB) is proposed.

In particular, the LM (Levenberg-Marquardt) method having the fast convergence speed of the Gauss-Newton method and stable convergence of the gradient descent method among the nonlinear least squares method can be selected to perform the position estimation.

In order to reduce the probability of misdiagnosis according to the divergence and local characteristics of the nonlinear least squares method, the DOA of the signal source using the TDOA and the maximum position estimation range based on the receiver sensitivity of the receiver are combined, . Accordingly, the position can be estimated based on a small number of receivers.

1 is a block diagram illustrating an apparatus for estimating a position of a fixed-signal source according to an embodiment of the present invention.

1, a stationary signal source position estimating apparatus 100 according to the present invention includes a DOA calculating unit 110, an initial position calculating unit 120, a position estimating unit 130, and a position calculating unit 140, .

DOA calculation portion 110, on the basis of the TDOA (time difference of arrival) value for the first moving receiver and the second moving receiver receiving a signal from a fixed signal source, value, candidates for the DOA (direction of arrival) DOA 1 And DOA 2 are calculated.

Calculating the initial position unit 120, the calculating the DOA 1 And DOA 2 Based on the value and the maximum position estimation range of the reception of the first moving receiver and the second moving receiver, and calculates the initial value of position x 0 (1) and x 0 (2) of the fixed signal source.

The position estimating unit 130 calculates TDOA, frequency difference of arrival (FDOA), DOA 1, and DOA 2 , which are measured according to the calculated time x 0 (1) and x 0 (1) and g (2), which are the absolute values of the residual corresponding to the respective estimated position values, are calculated by applying the squared method to the position estimate values x (1) and x do.

Here, the residual corresponding to each of the position estimation values may be defined as a matching of the algorithm and values applied to the algorithm.

In addition, the position estimating unit 130 may use an LM (Levenberg-Marquardt) algorithm with the nonlinear least squares method.

The position calculating unit 140 calculates one of x (1) and x (2) as the position of the fixed signal source based on the calculated values of g (1) and g (2).

As an example, the position calculating unit 140 may calculate the position of the fixed signal source that the absolute value of the corresponding residual of x (1) and x (2) is smaller.

2 is a flowchart illustrating an embodiment of a method of estimating the position of a fixed signal source according to the present invention.

2, first, the DOA calculation unit 110 calculates a time difference of arrival (DOA) based on a time difference of arrival (TDOA) value for a first mobile receiver and a second mobile receiver that receive a signal from a fixed signal source, a step (S210) and proceeds to calculate a candidate value DOA DOA 1 and 2 in the direction of arrival).

Subsequently, the initial position calculating unit 120 calculates the DOA 1 And DOA 2 Values and wherein the step of first moving, based on the receiver and the maximum position estimation range of the reception sensitivity of the second mobile receiver, calculating the initial position value of x 0 (1) and x 0 (2) of the fixed signal source (S220 ).

By then, the position estimating unit 130, the calculating the x 0 (1) and x 0 (2), TDOA, FDOA (frequency difference of arrival) is measured according to the successive time, DOA 1 and DOA 2 (1) and g (1), which are absolute values of the residual corresponding to the respective estimated position values, and g (1) (S230) of calculating the value (2) is proceeded.

As an example, step S230 may include using the LM (Levenberg-Marquardt) algorithm with the nonlinear least squares method.

The residual corresponding to each of the position estimate values may be defined as a matching of the algorithm and values applied to the algorithm.

Thereafter, the position calculating unit 140 calculates one of x (1) and x (2) as the position of the fixed signal source based on the calculated values of g (1) and g (2) (S240) is performed.

As an example, the step S240 may include calculating a smaller absolute value of the corresponding one of the x (1) and x (2) as the position of the fixed signal source.

Hereinafter, an apparatus and method for estimating the position of a fixed-signal source according to the present invention will be described with reference to specific examples of mathematical expressions and algorithms.

3 is a conceptual diagram for explaining the concept of direction detection using TDOA.

Referring to FIG. 3, when the fixed signal source 310 is assumed to be remotely located, the wave front of the signal radiated from the fixed signal source 310 becomes almost straight.

If direction detection is performed only within the range of 0 DEG to 180 DEG, the following equation (2) regarding the direction of arrival (DOA) can be calculated from the following equation (1) regarding time difference of arrival (TDOA) have.

Figure 112015074371327-pat00001

Figure 112015074371327-pat00002

Where B is the distance between r i and r j .

However, in the range of 0 deg. To 360 deg., Ambiguity of the DOA occurs. Hereinafter, the present invention will be described in detail with reference to the drawings.

FIGS. 4 and 5 are conceptual diagrams for explaining the ambiguity of the DOA generated according to the TDOA.

Specifically, FIG. 4 is an example showing the ambiguity of the DOA of the fixed signal source generated according to the measured value of TDOA. That is, the location of the stationary signal source can be estimated at two locations 410, 420.

5 is a conceptual diagram showing an embodiment in which the same TDOA value is measured in different orientations.

Referring to FIG. 5, it can be seen that the same TDOA value is measured for different orientations. This means that two DOA values are calculated in the range of 0 DEG to 360 DEG. That is, one of them is the actual DOA value and the other one is the DOA value generated by ambiguity. At this time, each value can be expressed by DOA 1 (tn) and DOA 2 (tn).

Combining the DOA 1 (tn) and DOA 2 (tn) derived using the TDOA with the maximum position estimation range based on the receiver sensitivity of the receiver, the initial position values x 0 (1) and x 0 (2) can be calculated according to the following equation (3).

Figure 112015074371327-pat00003

At this time, Rmax denotes a maximum position estimation range. In addition, as described above, the position estimation can be performed using the LM method having the advantages of the Gauss-Newton method and the gradient descent method for stability of the position estimation and convergence.

The measurement data of TDOA, FDOA and DOA can be defined as the following Equations (4) to (6).

Figure 112015074371327-pat00004

Figure 112015074371327-pat00005

Figure 112015074371327-pat00006

here,

Figure 112015074371327-pat00007
,
Figure 112015074371327-pat00008
Is a measurement error of independent TDOA, a measurement error of FDOA, and a Gaussian probability distribution. And,
Figure 112015074371327-pat00009
Is a side error of the DOA, and is a DOA using TDOA, and thus has a correlation as shown in Equation (7).

Figure 112015074371327-pat00010

Figure 112015074371327-pat00011

here,

Figure 112015074371327-pat00012
Is a transpose matrix. In addition, the mathematical model of TDOA, FDOA, and DOA can be expressed as M (x) as shown in Equation (8).

Figure 112015074371327-pat00013

Here, the cost function f (x) of the LM method can be defined as the following Equation (9).

Figure 112015074371327-pat00014

6 is a conceptual diagram showing an embodiment of the LM method.

Referring to FIG. 6, ε 1 is a constant indicating the termination condition of the LM method, ε 2 is a step size, and τ and kmax are a user defined constant and a maximum number of iterations of the algorithm, respectively. And j (x) is a Jacobian matrix of f (x).

Specifically, x 0 (1) and x 0 (2) are set as the initial position values of the fixed signal source, and DOA 1 and DOA 2 in the corresponding directions are set. It also has TDOA and FDOA information as input.

The outputs have positions x (1) and x (2) of the estimated stationary signal source, respectively. Then, ∥g (1) ∥, ∥g (2) ∥, which are the absolute values of the residuals indicating the degree of matching between the model of the algorithm and the measurement information, are output. As this value becomes smaller, It means that the degree is large.

Based on the meaning of these residuals, the position calculation unit 140 compares the sizes of ∥g (1) ∥ and ∥g (2) ∥ to select a relatively small value, Finally, you choose.

As a result, according to the present invention, time difference of arrival (TDOA), frequency difference of arrival (FDOA), and DOA (direction of arrival) of arrival information is available. Specifically, the position of the fixed signal source can be estimated with a small number of receivers based on the nonlinear least squares method.

In order to improve the stability of the LM (Levenberg-Marquardt) algorithm, which is one of the nonlinear least squares methods, the position of the initial signal source can be selected. As a result, the position of the stationary signal source can be stably estimated even with a small number of receivers.

As described above, the method of estimating the position of the stationary signal source is not limited to the configuration and method of the above-described embodiments, but the embodiments may be modified such that all or some of the embodiments are selectively And may be configured in combination.

The present invention described above can be embodied as computer-readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). In addition, the above detailed description should not be construed in all aspects as limiting and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

110 - DOA calculation unit
120 - initial position calculating section
130 -
140 - Position calculation section

Claims (8)

A DOA calculation that calculates DOA 1 and DOA 2, which are candidate values of a DOA (direction of arrival), based on a time difference of arrival (TDOA) value for a first mobile receiver and a second mobile receiver that receive signals from a fixed signal source part;
The calculated DOA 1 And DOA 2 Based on the value and the maximum position estimation range of the reception of the first moving receiver and the second moving receiver, calculating the initial position for calculating the initial position value of x 0 (1) and x 0 (2) of the fixed signal source part;
By applying the calculation by x 0 (1) and x 0 (2), the value of the TDOA, FDOA (frequency difference of arrival), DOA 1 and DOA 2, measured according to the continuous time in a non-linear least square method, the fixing signal A position estimator for calculating g (1) and g (2), which are absolute values of residuals corresponding to the respective position estimation values, x (1) and x And
And a position calculating unit for calculating one of the x (1) and x (2) as the position of the fixed signal source based on the calculated values of g (1) and g (2) The position of the stationary signal source. The method according to claim 1,
The position estimating unit may calculate,
Wherein the LM (Levenberg-Marquardt) algorithm is used in the nonlinear least squares method. 3. The method of claim 2,
Wherein the residual corresponding to each of the position estimate values means a degree of matching of the algorithm and values applied to the algorithm. The method of claim 3,
The position calculating unit calculates,
Wherein the position of the fixed signal source is calculated as the absolute value of the corresponding one of the x (1) and the x (2). (a) a DOA calculation unit configured to calculate a DOA (direction of arrival) candidate value (DOA) based on a time difference of arrival (TDOA) value for a first mobile receiver and a second mobile receiver that receive a signal from a fixed signal source, 1 and DOA 2 ;
(b) The initial position calculating unit calculates the DOA 1 And DOA 2 Calculating a value and the first moving receiver and the initial position value of x 0 (1) and x 0 (2) of the fixed signal source based on the maximum position estimation range by the reception sensitivity of the second mobile receiver;
(c) TDOA, frequency difference of arrival (FDOA), DOA 1 and DOA 2 values measured according to the calculated continuous x 0 (1) and x 0 (2) (1) and g (2), which are the absolute values of residuals corresponding to the respective estimated position values, are obtained by applying the least squares method to the position estimate values x (1) and x Calculating; And
(d) calculating one of the x (1) and x (2) as the position of the fixed signal source based on the calculated values of g (1) and g (2) And estimating a position of the fixed signal source. 6. The method of claim 5,
The step (c)
And using an LM (Levenberg-Marquardt) algorithm with the nonlinear least squares method. The method according to claim 6,
Wherein the residual corresponding to each of the position estimate values means a degree of matching of the algorithm and values applied to the algorithm. 8. The method of claim 7,
The step (d)
And calculating a position of the fixed signal source in which the absolute value of the corresponding one of the x (1) and the x (2) is smaller.
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KR20180085910A (en) * 2017-01-20 2018-07-30 국방과학연구소 Method for adaptive geo-positioning detection based on tdoa applied to multi-aircraft platform
KR20180107964A (en) * 2017-03-23 2018-10-04 국방과학연구소 Method and apparatus for positioning using combination of tdoa/fdoa

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KR20140090746A (en) * 2013-01-10 2014-07-18 이흥수 Location detection system and method

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