KR102470953B1 - Apparatus and method for estimating location with low complexity based on lens antenna array using GPS information - Google Patents

Abstract

The present invention is transmitted from a UAV through a lens antenna unit including a plurality of antennas arranged at predetermined intervals and a lens arranged apart from the plurality of antennas by a predetermined focal distance to focus an incident RF signal, and through the lens antenna unit An RF signal receiving unit that acquires a received signal, which is an RF beacon signal, a GPS information acquisition unit that obtains GPS information on the current location of the UAV and calculates a GPS incident angle according to the relative position with the UAV based on the obtained GPS information, and a lens antenna UAV including an azimuth estimation unit obtained by approximating the angle of incidence of the received signal incident to the negative and the estimated angle of incidence that maximizes the likelihood calculated by the conditional probability density function for the received signal in the form of an approximate formula for the angle of incidence of GPS according to the Taylor approximation technique It is possible to provide a lens antenna-based orientation estimating device and method capable of accurately estimating the UAV direction by compensating for the GPS information error of the UAV.

Description

Apparatus and method for estimating location with low complexity based on lens antenna array using GPS information}

The present invention relates to an apparatus and method for estimating a direction based on a lens antenna, and relates to an apparatus and method for estimating a direction based on a low-complexity lens antenna using GPS information.

Free space optical communication (FSO) is an optical signal transmitted through an air medium without a transmission line composed of optical fibers, so there are no restrictions on transmission speed and transmission capacity, and there are no restrictions on frequency use. In addition, since data is transmitted through space as a medium, cost and installation time required for fiber optic installation are drastically reduced compared to wired optical communication, and an effective communication network can be configured.

FSO is generally a method of transmitting an optical signal using a laser, and is mainly used outdoors and can easily perform communication at a distance of several km.

1 shows an example of an FSO communication system.

As shown in FIG. 1, the FSO system may be configured with a UAV-based network structure using an Unmanned Aerial Vehicle (UAV) to build a flexible communication network. In a UAV-based network structure, at least one UAV and a ground base station (GBS) transmit and receive optical signals using a laser or the like to provide high-speed communication through a very wide bandwidth.

As such, the FSO communication network built on the basis of the UAV can secure a flexible LOS link by utilizing the mobility of the UAV for the FSO link with high LOS (Line-Of-Sight) sensitivity, reducing construction cost and meeting network capacity requirements. It is attracting attention as a next-generation high-speed and high-efficiency communication system because it has additional benefits such as securing flexibility in response to

However, in order to perform stable communication at a long distance using an optical signal having high linearity such as a laser, it is necessary to accurately irradiate the optical signal to the other party. That is, the UAV and the GBS must accurately identify each other's location and transmit an optical signal in a direction corresponding to the confirmed location. In the case of GBS, it has a fixed location on the ground, but since UAV is mobile, its location changes from time to time. Therefore, for FSO communication, GBS must be able to accurately determine the location of the UAV and transmit optical signals in the confirmed direction. .

Accordingly, conventionally, a UAV obtains GPS (Global Positioning System) information indicating its location using a satellite (SAT), and transmits the obtained GPS information to GBS, so that mutual FSO communication can be performed.

However, as is well known, GPS information also has a certain level of error, and the error of this GPS information typically exceeds the error limit required to transmit optical signals in FSO communications. Therefore, there is a need for a technique capable of accurately estimating the direction in which the UAV is positioned so that the optical signal is stably transmitted to the UAV.

Korean Patent Publication No. 10-2018-0094943 (published on August 24, 2018)

An object of the present invention is to provide an apparatus and method for estimating azimuth based on a lens antenna capable of accurately estimating a UAV direction by compensating for an error in GPS information of a received UAV.

Another object of the present invention is to obtain a function for estimating the error between the actual direction in which the UAV is located and the direction according to the GPS information based on the previously obtained GPS information and the RF received signal applied through the lens antenna, without additional information. An object of the present invention is to provide an apparatus and method for estimating a direction based on a lens antenna capable of accurately estimating a UAV direction using only GPS information.

In order to achieve the above object, a lens antenna-based orientation estimation device according to an embodiment of the present invention is a plurality of antennas arranged spaced apart at predetermined intervals and an RF signal incident from the plurality of antennas spaced apart from each other by a predetermined focal distance. A lens antenna unit including a lens for focusing; an RF signal receiving unit for obtaining a received signal ( x ) that is an RF beacon signal transmitted from an unmanned aerial vehicle (UAV) through the lens antenna unit; a GPS information acquisition unit that obtains GPS information about the current location of the UAV and calculates a GPS incident angle (ø _gps ) according to a relative location with the UAV based on the obtained GPS information; and estimation that maximizes the likelihood calculated by the conditional probability density function (f(ø| x )) for the received signal ( x ) and the angle of incidence (ø) of the received signal ( x ) incident on the lens antenna unit. It includes an orientation estimating unit for approximating the incident angle (ø _est ) in the form of an approximation formula for the GPS incident angle (ø _gps ) according to a Taylor approximation technique.

The direction estimator converts the difference between the expected signal from which noise is removed from the received signal ( x ) and the received signal ( x ) into the difference between the GPS incident angle (ø _gps ) and the incident angle (ø) of the actual received signal ( x ). Taking into account, the approximated equation for the estimated angle of incidence (ø _est )

(Where g is the received power of the received signal ( x ), A ( ø _gps ) is the amplitude of the received signal ( x ) according to the GPS incidence angle ( ø _gps ), s is the steering vector, e ^jb is the distance between each antenna and the center of the lens Represents the phase change according to (z), γ is the signal-to-noise ratio (SNR) for the received signal, calculated as γ = g ² /2σ _n ² , and σ _gps represents the standard deviation for the GPS incident angle (ø _gps ). ) can be calculated according to

The orientation estimation unit is expressed by Equation

(Where g is the received power of the received signal ( x ), A (ø) represents the amplitude according to the angle of incidence (ø) of the received signal ( x ), s is the steering vector, e ^jb is the distance between each antenna and the center of the lens ( Represents the phase change according to z), and n represents noise. The amplitude ( A (ø)) of the sink form of the received signal ( x ) expressed as Equation

(Where n is the antenna index, L is the diameter of the lens, z is the distance between the antenna and the center of the lens, d is the distance between the antennas, λ represents the wavelength of the RF signal, and sinc[] represents the sync function.) have.

The GPS information obtaining unit may acquire and store the GPS information transmitted in the form of an RF signal from the UAV in advance.

The lens antenna-based orientation estimating apparatus may further include an optical communication unit configured to adjust a steering direction of an optical signal according to the obtained estimated incident angle ø _est and transmit/receive the optical signal in the adjusted steering direction.

A method for estimating a bearing based on a lens antenna according to another embodiment of the present invention for achieving the above object is arranged spaced apart at a predetermined interval from an unmanned aerial vehicle (UAV) through a plurality of antennas receiving RF signals focused by a lens. Obtaining a received signal ( x ) that is a transmitted RF beacon signal; Obtaining GPS information on the current location of the UAV, and calculating a GPS incident angle (ø _gps ) according to a relative location with the UAV based on the obtained GPS information; And to maximize the likelihood calculated by the conditional probability density function (f(ø| x )) for the received signal ( x ) and the incident angle (ø) at which the received signal ( x ) is incident on the plurality of antennas. A step of approximating the estimated angle of incidence (ø _est ) in the form of an approximate formula for the angle of incidence (ø _gps ) of the GPS according to a Taylor approximation technique and obtaining it.

Therefore, an apparatus and method for estimating azimuth based on a lens antenna according to an embodiment of the present invention is based on pre-obtained GPS information and an RF received signal applied through a lens antenna to determine the difference between the actual direction where the UAV is located and the direction according to the GPS information. A function for estimating an error may be obtained, and a UAV direction may be accurately estimated by compensating for an error in GPS information of the UAV received thereafter using the acquired function. Therefore, it is possible to perform stable FSO communication by accurately estimating the UAV direction only with GPS information without additional information.

1 shows an example of an FSO communication system.
2 shows a schematic structure of an orientation estimation device based on a lens antenna according to an embodiment of the present invention.
FIG. 3 shows a direction in which the lens antenna unit of FIG. 2 and a received signal are incident.
FIG. 4 shows an example of a difference between a received signal received by the lens antenna of FIG. 3 and an expected signal.
5 illustrates a lens antenna-based orientation estimation method according to an embodiment of the present invention.

In order to fully understand the present invention and its operational advantages and objectives achieved by the practice of the present invention, reference should be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the described embodiments. And, in order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals in the drawings indicate the same members.

Throughout the specification, when a part "includes" a certain component, it means that it may further include other components, not excluding other components unless otherwise stated. In addition, terms such as "... unit", "... unit", "module", and "block" described in the specification mean a unit that processes at least one function or operation, which is hardware, software, or hardware. And it can be implemented as a combination of software.

2 shows a schematic structure of an orientation estimation device based on a lens antenna according to an embodiment of the present invention, FIG. 3 shows a direction in which the lens antenna unit of FIG. 2 and a received signal are incident, and FIG. 4 shows the lens antenna of FIG. 3 An example of the difference between the received signal and the expected signal is shown.

Referring to FIG. 2, the lens antenna-based orientation estimation device according to the present embodiment includes a lens antenna unit 110, an RF signal receiver 120, a GPS information acquisition unit 130, a direction estimation unit 140, and an optical communication unit ( 150) may be included.

In this embodiment, it is assumed that the lens antenna-based direction estimation device is provided in the GBS and can receive an RF signal transmitted from the UAV or transmit the RF signal to the UAV. This is because the UAV is a mobile device whose location changes frequently, whereas the GBS is a fixed device on the ground. As shown in FIG. 1, in the FSO communication system, GBS and USV perform communication by transmitting and receiving optical signals. However, in order for the GBS and the UAV to communicate using optical signals, they must be able to accurately recognize each other's position and irradiate the optical signal in a direction according to the recognized position. Therefore, it is difficult to perform FSO communication until the location is accurately determined, and GBS must always control the UAV to designate the location to which the UAV must move. It consists of

In particular, in this embodiment, the UAV is an RF Beacon Signal (hereinafter referred to as RF signal) to the GBS so that the lens antenna-based orientation estimation device provided in the GBS can correct the error of the GPS information indicating the position of the UAV obtained in advance. can also be sent.

The lens antenna unit 110 transfers the RF signal transmitted from the USV to the RF signal receiver 120 .

As shown in FIG. 3, the lens antenna unit 110 is spaced apart from each other by a focal length (f) from the plurality of antennas (ANT) and the plurality of antennas (ANT) arranged at a predetermined interval (d). It includes lenses disposed spaced apart from each other. Here, the lens has a convex lens structure and focuses the RF signal transmitted from the UAV and incident in a form close to a plane wave. Each of the plurality of antennas ANT receives a focused RF signal through a lens.

At this time, since the plurality of antennas ANT receives the RF signals focused by the lens, the phases of the RF signals received by the plurality of antennas ANT are different from each other. In particular, the phase of the RF signal received by the plurality of antennas ANT is different depending on the location where each antenna is disposed with respect to the center of the lens and the angle of incidence (or angle of arrival) ø of the RF signal. . Here, it is assumed that n antennas (ANTs) are arranged in a one-dimensional array, and the index of each antenna is expressed as n.

Further, the RF signal receiving unit 120 obtains the RF signal transmitted through the plurality of antennas ANT of the lens antenna unit 110 as a received signal ( x ) to the GPS information obtaining unit 130 and the direction estimation unit 140. convey

When an RF signal is received through the lens antenna unit 110 in a form similar to a plane wave, the RF signal receiver 120 receives a received signal (n) in the form of adding noise ( n ) to the amplitude ( A (ø)) of the sink form. x ) is obtained, and thus the received signal ( x ) can be expressed as in Equation 1.

where g is the received power of the received signal ( x ), A (ø) represents the amplitude according to the angle of incidence (ø) of the received signal ( x ), s is the steering vector, e ^jb is the distance between each antenna and the center of the lens (z ), and n represents noise.

And the amplitude ( A (ø)) is expressed by Equation 2.

(Where n is the antenna index, L is the diameter of the lens, z is the distance between the antenna and the center of the lens, d is the distance between the antennas, λ represents the wavelength of the RF signal, and sinc[] represents the sync function.)

Here, the received signal ( x ) is modeled as a signal model of a sink type and expressed using a sink function (sinc[]) as shown in Equation 2, but it may be modeled as a signal model of another type.

The GPS information acquisition unit 130 acquires GPS information indicating the location of the UAV. Here, the GPS information may receive GPS information from the UAV through RF communication, for example, and may obtain GPS information about the UAV in another method. When GPS information is received through RF communication, the GPS information obtainer 130 may extract and obtain GPS information from the received signal obtained by the signal receiver 120 .

And calculates the GPS angle of incidence (ø _gps ) from the position of the UAV according to the acquired GPS information. The GPS information acquiring unit 130 calculates a GPS incident angle (ø _gps ) by receiving previously applied GPS information from the UAV before transmitting an RF signal to the GBS. Here, the GPS angle of incidence (ø _gps ) may be obtained by calculating relative positions based on GPS location information obtained for the UAV and the GBS. In addition, the GPS amplitude ( A (ø _gps )) is calculated from the calculated GPS angle of incidence (ø _gps ). The GPS amplitude ( A (ø _gps )) can be calculated using Equation 2.

The direction estimation unit 140 receives the received signal ( x ) from the RF signal receiver 120, and calculates the GPS incident angle (ø _gps ) in the GPS information acquisition unit 130 based on the applied received signal ( x ). By correcting the error, the incident angle (ø) of the received signal ( x ) is estimated.

로 나타날 수 있으며, GPS 정보에 따른 UAV의 위치에 따른 GPS 입사각(ø_gps)에서의 신호로 고려할 수 있다. 즉 실제 UAV의 위치에서의 수신 신호(x)의 입사각(ø)과 GPS 정보에 따른 UAV의 위치에서의 GPS 입사각(ø_gps) 사이의 오차로 인해 노이즈가 발생된 것으로 고려할 수 있다.If the signal from which noise is removed from the received signal ( x ) in Equation 1 is called an expected signal, the expected signal is

, and can be considered as a signal at the GPS angle of incidence (ø _gps ) according to the position of the UAV according to the GPS information. That is, it can be considered that noise is generated due to an error between the angle of incidence (ø) of the received signal ( x ) at the location of the actual UAV and the angle of incidence (ø _gps ) of the GPS at the location of the UAV according to the GPS information.

In addition, the difference between the expected signal and the actual received signal ( x ) appears differently depending on the position of each antenna (ANT). 4 shows a difference in amplitude ( A (ø)) between a received signal ( x ) and an expected signal according to positions of each of a plurality of antennas (ANT). therefore

The difference between the incident angle ø of the received signal x with respect to the GPS incident angle ø _gps can be inversely estimated from the difference between the received signal x actually received by the plurality of antennas ANT and the expected signal. That is, the GPS incidence angle (ø _gps ) can be estimated using the difference between the received signal ( x ) for each of the plurality of antennas (ANT) and the expected signal (ø) for the actual received signal ( x ).

As described above, if the difference between the received signal ( x ) and the expected signal is considered as noise, the likelihood of the received signal ( x ) according to the incident angle (ø) can be obtained. Here, the likelihood is the probability that the received signal appears as shown in Equation 1 when the incident angle (ø) is determined, and is calculated using the conditional probability density function (f(ø| x )) for the incident angle (ø) and the received signal ( x ). It can be calculated with the conditional probability as shown in Equation 3.

Further, the orientation estimator 140 aims to estimate an incident angle (ø _est ) that maximizes the conditional probability (f(ø| x )) of Equation 3. That is, the objective function of the orientation estimator 140 may be expressed by Equation 4.

However, since it is assumed here that the received signal ( x ) has the form of a sync function, the conditional probability density function for calculating the _likelihood also does not appear in the form of a convex function. , In order to find the solution of Equation 4, a full search for all possible angles of incidence (ø) is required. However, since full search for all angles of incidence (ø) requires a lot of computation, real-time processing is difficult. In particular, since the position of the UAV may be frequently moved, it is necessary to be able to estimate the estimated angle of incidence (ø _est ) with a maximum likelihood with low complexity.

Accordingly, the direction estimation unit 140 of the present embodiment corrects the error of the GPS angle of incidence (ø _gps ) calculated based on the GPS information acquired by the GPS information acquisition unit 130, and obtains the received signal ( x ) having the maximum likelihood. Estimate the estimated angle of incidence (ø _est ) with low complexity.

In Equation 3, the conditional probability (f( x |ø)) for the received signal ( x ) and the angle of incidence (ø) and the probability (f(ø)) for the angle of incidence (ø) according to the probability density function (f()) are calculated by Equations 5 and 6, respectively.

Here, * denotes a Hermitian matrix, and σ _n denotes a standard deviation of incident angles (ø) of N antennas (ANT).

Here, σ _gps represents the standard deviation for the GPS angle of incidence (ø _gps ).

In addition, in order to obtain an estimated angle of incidence (ø _est ) that satisfies Equation 4, Equation 7 may be obtained from Equation 3.

The angle of incidence ø that satisfies Equation 7 is the angle of incidence ø for the maximum or minimum point of the conditional probability f(ø| x ), and may be referred to as the estimated incident angle ø _est .

는 수학식 5로부터 수학식 8과 같이 획득될 수 있다.And in Equation 7

Can be obtained from Equation 5 as in Equation 8.

는 수학식 9로 계산된다.in Equation 8

is calculated by Equation 9.

On the other hand, assuming that GPS information has a general level of reliability, given the GPS incident angle (ø _gps ), the GPS probability (f(ø _gps )) and the conditional probability (f( x ) according to the probability density function (f()) The product of |ø)) is proportional to the conditional probability (f(ø| x )) for the received signal ( x ) applied from the actual UAV. Therefore, the conditional probability f(ø| x ) for the incident angle ø and the received signal x can be calculated from the GPS probability f(ø _gps ) and the conditional probability f( x |ø).

Therefore, given the GPS incident angle (ø _gps ), the amplitude ( A (ø)) of Equation 2 can be approximated as in Equation 10 according to the Taylor approximation technique.

Here , A' (ø _gps ) represents the derivative of A (ø _gps ).

And when the Taylor approximated amplitude of Equation 10 is applied to Equation 9, Equation 8 is expressed as Equation 11.

Also, f'( x |ø) in Equation 7 is expressed by Equation 12.

When Equation 7 is calculated using the approximations of Equations 11 and 12, the estimated incident angle (ø _est ) can be calculated according to Equation 13.

Here, γ is the signal-to-noise ratio (SNR) of the received signal and can be calculated as γ = g ² /2σ _n ² .

As a result, the orientation estimator 140 according to the present embodiment corresponds to the position of the UAV from the GPS amplitude A (ø _gps ) obtained from the GPS information and the received signal ( x ) in Equation 13 approximated by the Taylor approximation technique The estimated angle of incidence (ø _est ) can be easily obtained with a small amount of computation.

The optical communication unit 150 transmits and receives an optical signal by steering in the UAV direction according to the estimated incident angle (ø _est ) estimated by the azimuth estimation unit 140 . The optical communication unit 150 may include a light steering unit 151 and an optical transmission/reception unit 152 . The light steering unit 151 adjusts the direction for transmitting or receiving the light signal according to the estimated incident angle ø _est estimated by the direction estimation unit 140 . Further, the light transmission/reception unit 152 may transmit an optical signal in the direction steered by the light steering unit 151 or may detect a received optical signal and convert it into an electrical signal. The light transmitting/receiving unit 152 may include a laser device or a light detector.

In the above, the case where the lens antenna-based direction estimation device is provided in the GBS has been described as an example, but the movement of the UAV may cause the need to adjust the direction so that the UAV can also irradiate an optical signal to the GBS. Accordingly, the lens antenna-based direction estimation device may also be provided in a UAV.

5 illustrates a lens antenna-based orientation estimation method according to an embodiment of the present invention.

Referring to FIGS. 1 to 4, the lens-antenna-based direction estimation method of FIG. 5 is described. First, GPS information indicating location information of a UAV is acquired (S10). Then, based on the acquired GPS information, the relative position between the user's position and the position according to the GPS information is checked to calculate the GPS incidence angle (ø _gps ) (S20). Thereafter, a plurality of antennas (ANT) arranged at a predetermined interval (d) from the UAV and an RF signal incident from the plurality of antennas (ANT) spaced apart from each other by a focal distance (f) to the plurality of antennas (ANT) It is determined whether the RF beacon signal is received by the lens antenna unit 110 including the focusing lens (S30). When the RF beacon signal is received by the plurality of antennas (ANT) of the lens antenna unit 110, the RF beacon signal received by the plurality of antennas (ANT) is acquired as a received signal ( x ), and the obtained received signal ( x ) Based on Equation 13, the error of the previously obtained GPS angle of incidence (ø _gps ) is corrected to estimate the angle of incidence (ø _est ) for the received signal ( x ) obtained by transmitting the actual UAV (S40).

Then, the direction for transmitting or receiving the optical signal is adjusted to the UAV direction according to the estimated angle of incidence (ø _est ) (50). Thereafter, the light transmission/reception unit 152 transmits or receives an optical signal in the direction steered by the light steering unit 151 (S60).

The method according to the present invention may be implemented as a computer program stored in a medium for execution on a computer. Here, computer readable media may be any available media that can be accessed by a computer, and may also include all computer storage media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, including read-only memory (ROM) dedicated memory), random access memory (RAM), compact disk (CD)-ROM, digital video disk (DVD)-ROM, magnetic tape, floppy disk, optical data storage device, and the like.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

SAT: artificial satellite UAV: unmanned aerial vehicle
GBS: terrestrial base station 110: lens antenna unit
120: RF signal receiver 130: GPS information acquisition unit
140: direction estimation unit 150: optical communication unit
151: light steering unit 152: optical transmission and reception unit

Claims (10)

A lens antenna unit including a plurality of antennas spaced apart from each other at predetermined intervals and a lens arranged spaced apart from the plurality of antennas by a predetermined focal distance to focus an incident RF signal;
an RF signal receiving unit for obtaining a received signal ( x ) that is an RF beacon signal transmitted from an unmanned aerial vehicle (UAV) through the lens antenna unit;
a GPS information acquisition unit that obtains GPS information about the current location of the UAV and calculates a GPS incident angle (ø _gps ) according to a relative location with the UAV based on the obtained GPS information; and
The estimated incident angle maximizing the likelihood calculated by the incident angle ø of the received signal x incident on the lens antenna unit and the conditional probability density function f(ø| x ) for the received signal x A lens antenna-based orientation estimating device including an orientation estimating unit for approximating (ø _est ) in the form of an approximate formula for a GPS incidence angle (ø _gps ) according to a Taylor approximation technique. The method of claim 1, wherein the direction estimation unit
Considering the difference between the expected signal from which noise is removed from the received signal ( x ) and the received signal ( x ) as the difference between the GPS incident angle (ø _gps ) and the incident angle (ø) of the actual received signal ( x ), Equation approximating the estimated angle of incidence (ø _est )

(Where g is the received power of the received signal ( x ), A (ø _gps ) is the amplitude of the received signal ( x ) according to the GPS incidence angle (ø _gps ), A' (ø _gps ) is the derivative of A (ø _gps ), s is the steering vector, e ^jb represents the phase change according to the distance (z) between each antenna and the center of the lens, γ is the signal-to-noise ratio (SNR) for the received signal, calculated as γ = g ² /2σ _n ² , and σ _gps represents the standard deviation for the GPS angle of incidence (ø _gps ).
A lens antenna-based orientation estimation device that calculates according to The method of claim 2, wherein the direction estimation unit
math formula

(Where g is the received power of the received signal ( x ), A (ø) represents the amplitude according to the angle of incidence (ø) of the received signal ( x ), s is the steering vector, e ^jb is the distance between each antenna and the center of the lens ( represents the phase change according to z), and n represents the noise.)
The amplitude ( A (ø)) of the sink form of the received signal ( x ) expressed by Equation

(Where n is the antenna index, L is the diameter of the lens, z is the distance between the antenna and the center of the lens, d is the distance between the antennas, λ represents the wavelength of the RF signal, and sinc[] represents the sync function.)
A lens antenna-based orientation estimation device that calculates with The method of claim 1, wherein the GPS information obtaining unit
A lens antenna-based orientation estimation device for obtaining and pre-stores the GPS information transmitted in the form of an RF signal from the UAV. The method of claim 1, wherein the lens antenna-based orientation estimation device
A lens antenna-based orientation estimating device further comprising an optical communication unit configured to adjust a steering direction of an optical signal according to the obtained estimated angle of incidence (ø _est ) and to transmit and receive an optical signal in the adjusted steering direction. Acquiring a received signal ( x ), which is an RF beacon signal transmitted from an unmanned aerial vehicle (hereinafter referred to as UAV) through a plurality of antennas spaced apart at predetermined intervals and receiving RF signals focused by lenses;
Obtaining GPS information on the current location of the UAV, and calculating a GPS incident angle (ø _gps ) according to a relative location with the UAV based on the obtained GPS information; and
Estimation that maximizes the likelihood calculated by the conditional probability density function (f(ø| x )) for the received signal ( x ) and the incident angle (ø) at which the received signal ( x ) is incident on the plurality of antennas. A method for estimating a direction based on a lens antenna, comprising approximating and obtaining an angle of incidence (ø _est ) in the form of an approximate formula for the angle of incidence (ø _gps ) of GPS according to a Taylor approximation technique. The method of claim 6, wherein the step of obtaining by approximating the GPS incidence angle (ø _gps )
Considering the difference between the expected signal from which noise is removed from the received signal ( x ) and the received signal ( x ) as the difference between the GPS incident angle (ø _gps ) and the incident angle (ø) of the actual received signal ( x ), Equation approximating the estimated angle of incidence (ø _est )

(Where g is the received power of the received signal ( x ), A ( ø _gps ) is the amplitude of the received signal ( x ) according to the GPS incidence angle ( ø _gps ), s is the steering vector, e ^jb is the distance between each antenna and the center of the lens Represents the phase change according to (z), γ is the signal-to-noise ratio (SNR) for the received signal, calculated as γ = g ² /2σ _n ² , and σ _gps represents the standard deviation for the GPS incident angle (ø _gps ). )
A lens antenna-based orientation estimation method calculated according to. The method of claim 7, wherein the received signal is
math formula

(Where g is the received power of the received signal ( x ), A (ø) represents the amplitude according to the angle of incidence (ø) of the received signal ( x ), s is the steering vector, e ^jb is the distance between each antenna and the center of the lens ( represents the phase change according to z), and n represents the noise.)
It is expressed as, and the amplitude ( A (ø)) of the sink form of the received signal ( x ) is expressed by Equation

(Where n is the antenna index, L is the diameter of the lens, z is the distance between the antenna and the center of the lens, d is the distance between the antennas, λ represents the wavelength of the RF signal, and sinc[] represents the sync function.)
A lens antenna-based orientation estimation method calculated by The method of claim 6, wherein the step of calculating the GPS angle of incidence (ø _gps )
obtaining and previously storing the GPS information transmitted in the form of an RF signal from the UAV; and
and obtaining the GPS incidence angle (ø _gps ) by calculating a relative position to the UAV from the stored GPS information. The method of claim 6, wherein the lens antenna-based orientation estimation method
adjusting the steering direction of the optical signal according to the obtained estimated incident angle (ø _est ); and
A method for estimating a bearing based on a lens antenna, further comprising transmitting and receiving an optical signal in the adjusted steering direction.

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