JP7380779B1 - Mobile objects, methods and programs - Google Patents

Abstract

[Problem] To improve problems in communication. [Solution] A moving object, which includes a storage section that stores position information of a radio wave source, an array antenna, an attitude angle acquisition section that obtains an attitude angle of the moving object, and a position defined on the antenna surface of the array antenna. a first set of two points spaced apart in a first direction; and a second set of two points spaced apart in a second direction perpendicular to said first direction; The position of each of the at least three points having a position is calculated based on the attitude angle of the moving body, and path difference information between each of the two points of the first set and the position indicated by the position information of the radio wave source is calculated. , and a direction calculation unit that calculates the direction of the radio wave source based on path difference information between each of the two points of the second set and the position indicated by the position information of the radio wave source; A mobile object, comprising: a calculation unit that calculates a complex weight for giving directivity to communication in the array antenna based on a direction. [Selection diagram] Figure 4

Description

The present invention relates to a mobile object, a method, and a program.

Conventionally, as a technology to reduce interference when multiple wireless systems share a frequency, a base station uses an array antenna to estimate the direction of arrival of radio waves from nearby radio sources, and then assigns the main signal to the desired wave. Adaptive antenna technology is known in which a beam is directed and other incoming waves form a directivity with a null point directed.

For example, Patent Document 1 discloses an adaptive antenna technology applied to a mobile terminal, which is a technology for controlling antenna directivity according to the orientation or inclination of the mobile terminal.

Japanese Patent Application Publication No. 2004-64741

However, in the conventional technology, directional transmission from a mobile body may interfere with communications in other wireless systems. For example, if the attitude of the moving object changes between the timing when the direction of the radio wave source as seen from the moving object is estimated and the timing when the radio waves are transmitted, the radio waves will be transmitted with the directionality directed toward the interference wave source. This is a concern.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved mobile object, method, and program that can improve communication problems. It's about doing.

In order to solve the above problems, according to one aspect of the present invention, a mobile body includes a storage unit that stores position information of a radio wave source, an array antenna, and an attitude angle that acquires an attitude angle of the mobile body. an acquisition unit; a first set of at least three points defined on the antenna surface of the array antenna, two points separated in a first direction; and a second set of two points orthogonal to the first direction; the position of each of the at least three points having a second set of two points spaced apart in the direction of is calculated based on the attitude angle of the moving body, and the position of each of the two points of the first set and the of the radio wave source based on path difference information between the position indicated by the radio wave source position information and path difference information between each of the two points of the second set and the position indicated by the radio wave source position information. A moving body is provided, which includes an azimuth calculation unit that calculates an azimuth, and an arithmetic unit that calculates a complex weight for giving directivity to communication in the array antenna based on the azimuth of the radio wave source.

The mobile body further includes a positioning sensor that has a positioning antenna and performs positioning based on a signal received by the positioning antenna, and the azimuth calculation unit calculates the position of each of the at least three points. In addition to the attitude angle of the mobile object, the calculation may be based on position information obtained by the positioning sensor.

The mobile body includes a direction estimation unit that estimates a relative direction of the radio wave source as viewed from the antenna surface based on a signal received from the radio wave source by each antenna element constituting the array antenna; is converted into an absolute direction with the direction of gravity as a reference based on the attitude angle of the moving object, and the absolute direction of the radio wave source obtained at a plurality of times and the relative direction obtained by the positioning sensor at the plurality of times are determined. The radio wave source may further include a position estimating unit that estimates position information of the radio wave source based on the obtained position information.

The calculation unit calculates a complex weight for giving directivity such that a beam is directed toward the radio wave source when the radio wave source is a communication partner, and calculates a complex weight for giving the radio wave source directivity such that the beam is directed to the radio wave source when the radio wave source is an interference partner. Complex weights may be calculated to provide directivity such that the null points toward the source.

Each of the two points of the first set is separated by 1/2 wavelength or more of a radio wave in the first direction, and each of the two points of the second set is separated from each other in the second direction. may be separated by 1/2 wavelength or more of the radio wave.

The at least three points consist of two points included in the first set and two points included in the second set that are different from the two points included in the first set. , may be four points.

According to another aspect of the present invention, in order to solve the above problems, there is provided a method executed by a mobile body having an array antenna, the method comprising: storing position information of a radio wave source; a first set of at least three points defined on a surface, two points spaced apart in a first direction, and a first set of two points spaced apart in a second direction orthogonal to said first direction; calculating the position of each of the at least three points having a second set based on the attitude angle of the moving body; and the position information of each of the two points of the first set and the radio wave source indicated. Calculating the azimuth of the radio wave source based on path difference information with respect to the position and path difference information between each of the two points of the second set and the position indicated by the position information of the radio wave source; A method is provided, including calculating complex weights for imparting directivity to communications in the array antenna based on the orientation of the radio wave source.

According to another aspect of the present invention, in order to solve the above problems, position information of a radio wave source is stored in a mobile body having an array antenna, and at least said three points having a first set of two points spaced apart in a first direction and a second set of two points spaced apart in a second direction orthogonal to said first direction; calculating the position of each of the at least three points based on the attitude angle of the moving body; path difference information between each of the two points of the first set and the position indicated by the position information of the radio wave source; and calculating the direction of the radio wave source based on path difference information between each of the two points of the second set and the position indicated by the position information of the radio wave source, and based on the direction of the radio wave source. and calculating complex weights for imparting directivity to communication in the array antenna.

According to the present invention described above, it is possible to improve problems in communication.

FIG. 1 is an explanatory diagram showing an example of the configuration of a wireless system according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a specific example of the directivity of a radio signal transmitted by the flying object 20. FIG. FIG. 1 is an explanatory diagram showing the configuration of a flying object 20 according to an embodiment of the present invention. 3 is an explanatory diagram showing the configuration of a communication control section 300. FIG. 2 is a flowchart showing an outline of the operation of the flying object 20. FIG. It is a flowchart which shows transmission processing. 7 is a flowchart showing the flow of coordinate transformation. It is an explanatory view showing four points defined on an antenna plane. It is an explanatory view showing relative position Pt of an incoming wave source. 3 is a flowchart showing the flow of calculating a transmission direction. FIG. 3 is an explanatory diagram showing a change in posture of a moving body.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that, in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals and redundant explanation will be omitted.

Further, in this specification and the drawings, a plurality of components having substantially the same functional configuration may be distinguished by using different alphabets after the same reference numeral. However, if there is no particular need to distinguish each of the plurality of components having substantially the same functional configuration, only the same reference numerals are given to each of the plurality of components.

<1. Wireless system overview>
One embodiment of the present invention relates to a wireless system, and particularly to a flying vehicle that constitutes a wireless system. Hereinafter, with reference to FIG. 1, an overview of a wireless system and a flying object according to an embodiment of the present invention will be described.

FIG. 1 is an explanatory diagram showing a configuration example of a wireless system according to an embodiment of the present invention. FIG. 1 shows an interference wave source 30A and an interference wave source 30B, which are other wireless systems, in addition to a wireless base station 10 and a flying object 20 that constitute a wireless system according to an embodiment of the present invention.

The wireless base station 10 is an example of a wireless communication device installed on the ground. The wireless base station 10 wirelessly communicates various data with the flying object 20, as indicated by solid bidirectional arrows in FIG. For example, the wireless base station 10 may receive sensor data detected on the aircraft 20, image data obtained by imaging on the aircraft 20, and the like.

The flying object 20 is an example of a moving object. The flying object 20 is a device that flies in the air. The flying vehicle 20 is, for example, a multicopter, and may be a manned flying vehicle or an unmanned aerial vehicle (UAV). The flying object 20 flies, for example, according to a control signal received from the wireless base station 10 or according to a preset movement plan. Further, the flying object 20 has an array antenna. The flying object 20 is capable of wireless communication with the wireless base station 10 via an array antenna.

Wireless communication may also be performed between the interference wave source 30A and the interference wave source 30B. The radio signals transmitted by these interference wave sources 30A and 30B can reach the aircraft 20 as interference waves. Similarly, when the flying object 20 transmits a radio signal to the radio base station 10 without special measures, the radio signal is transmitted as an interference wave to the interference wave source 30A and the interference wave source 30B, as shown by the broken line arrow in FIG. can be reached. Note that the radio base station 10, the interference wave source 30A, and the interference wave source 30B are examples of radio wave sources.

Therefore, the flying object 20 imparts directivity to the radio signal transmitted from the array antenna to the radio base station 10 in order to reduce interference with other radio systems such as the interference wave source 30A and the interference wave source 30B. A specific example of the directivity will be described with reference to FIG. 2.

FIG. 2 is an explanatory diagram showing a specific example of the directivity of a radio signal transmitted by the aircraft 20. As shown in FIG. 2, the radio signal transmitted by the aircraft 20 has a beam directed in the direction of the radio base station 10, and the directions of the interference wave sources 30A and 30B (as seen from the aircraft 20). A direction in which the null is directed to the direction in which the interference wave source 30B is located is given. The null is the direction in which the gain decreases significantly. According to this configuration, while realizing smooth wireless communication with the wireless base station 10, the interference that the flying object 20 gives to the interference wave source 30A and the interference wave source 30B is reduced.

Here, a method may be considered in which the aircraft 20 forms a directivity that directs a null toward the interference wave source 30 based on an estimated value of the direction of arrival of the radio waves transmitted from the interference wave source 30. However, the position or attitude of the aircraft 20 may change between the timing at which the arrival direction of the radio waves is estimated and the timing at which the aircraft 20 transmits the radio waves. In this case, because the direction of the interference wave source 30 at the timing when the aircraft 20 transmits radio waves and the estimated arrival direction of the radio waves transmitted from the interference wave source 30 are different, the beam is directed in the direction of the interference wave source 30. There is a risk that radio waves may be transmitted. Due to similar circumstances, there is a possibility that the beam may be directed in a direction different from the direction of the wireless base station 10.

The inventor of the present invention has created an embodiment of the present invention by focusing on the above-mentioned circumstances. According to one embodiment of the present invention, it is possible to more effectively reduce interference with other wireless systems such as the interference wave source 30A and the interference wave source 30B. Further, it is possible to realize smooth communication with the wireless base station 10 that is the communication partner. That is, according to one embodiment of the present invention, it is possible to improve some problems in communication. Hereinafter, the configuration and operation of the flying object 20 according to an embodiment of the present invention will be described in detail.

<2. Configuration of the aircraft>
FIG. 3 is an explanatory diagram showing the configuration of the flying object 20 according to an embodiment of the present invention. As shown in FIG. 3, the flying object 20 according to an embodiment of the present invention includes a flight control device 220, a driving device 230, a battery 240, and a wireless control device 250.

(flight control device)
Flight control device 220 includes a sensor group 222 and a flight control section 224. The sensor group 222 is a collection of various sensors. The sensor group 222 may include, for example, a GPS sensor (GPS: Global Positioning System) that functions as a positioning sensor, a gyro sensor (angular velocity sensor), an acceleration sensor, a barometric pressure sensor, a magnetic sensor, or an ultrasonic sensor.

The flight control unit 224 is a collection of a general-purpose processor and a main memory device, and has a function as an information processing device. The flight control unit 224 also has an input/output interface function for acquiring sensor data output from the sensor group 222. The flight control unit 224 also has a function of acquiring movement plan information from the outside and storing it, and controlling the drive device 230 so that the flying object 20 autonomously navigates according to the stored movement plan information. Known techniques may be used for aviation control by the flight control unit 224. Further, the flight control unit 224 has a function as an attitude angle acquisition unit that calculates the attitude angle of the flying object 20 using the sensor data and sensor data acquired from the sensor group 222, for example. Flight control unit 224 provides data such as attitude angle information and movement plan information to radio control device 250.

(drive device)
The drive device 230 is a device that generates a driving force for flight of the flying object 20. The drive device 230 includes, for example, a motor for making the flying object 20 fly, a propeller, and an ESC (Electric Speed Controller) that controls their rotational speed.

(Battery)
Battery 240 supplies power to flight control device 220, drive device 230, and wireless control device 250. Flight control device 220, drive device 230, and wireless control device 250 operate using power supplied from battery 240. Battery 240 may be, for example, a lithium ion polymer secondary battery or a lithium ion secondary battery.

(Wireless control device)
The wireless control device 250 is a configuration for performing wireless communication. As shown in FIG. 3, the radio control device 250 includes an array antenna 252, an RF receiving circuit 254, an RF transmitting circuit 258, and a communication control section 300.

The array antenna 252 has a plurality (N) of element antennas 1n (n=1, 2, . . . , N), and these element antennas are arranged on the antenna surface. Array antenna 252 is connected to RF receiving circuit 254 and RF transmitting circuit 258. Array antenna 252 converts the radio signal into an electrical high frequency reception signal and outputs it to RF reception circuit 254. Furthermore, the array antenna 252 converts the high frequency transmission signal supplied from the transmission processing section 390 into a wireless signal and transmits the radio signal.

The RF receiving circuit 254 performs high frequency processing such as down conversion and AD conversion of the high frequency received signal input from the array antenna 252. RF receiving circuit 254 outputs the received signal obtained by down conversion and AD conversion to communication control section 300.

The RF transmission circuit 258 performs high frequency processing such as DA conversion and up-conversion of the transmission signal input from the communication control unit 300. RF transmission circuit 258 outputs a high frequency transmission signal obtained by DA conversion and upconversion to array antenna 252.

The communication control unit 300 is a collection of a general-purpose processor and a main memory device, and has a function as an information processing device. The communication control unit 300 may be a FPGA (Field Programmable Gate Array), which is a programmable logic device (PLD), or an ASIC (ASIC). cific Integrated Circuit) etc. It may also be an IC for a specific use. Further, the communication control unit 300 may be a functional block that shares one hardware with the flight control unit 224.

The communication control unit 300 controls processing using a received signal inputted from the RF receiving circuit 254, processing for generating a transmitted signal outputted to the RF transmitting circuit 258, and the like. The detailed configuration of the communication control unit 300 will be described below with reference to FIG. 4.

<3. Configuration of communication control unit>
FIG. 4 is an explanatory diagram showing the configuration of the communication control section 300. As shown in FIG. 4, the communication control unit 300 includes a direction of arrival estimation unit 310, a reception directivity calculation unit 320, a reception processing unit 330, an incoming wave source position estimation unit 340, a storage unit 350, a transmission direction calculation unit 360, a fluctuation It has a prediction section 370, a transmission directivity calculation section 380, and a transmission processing section 390.

(Direction of arrival estimation unit)
The direction of arrival estimating section 310 has a function of estimating the direction of arrival of a radio signal from the received signal from each element antenna. For example, the direction of arrival estimation unit 310 uses the MUSIC (Multiple Signal Classification) method or the ESPRIT (Estimation of Signal Parameters via Rotation Invariance Technique). The arrival direction of the wireless signal is estimated using a high-resolution algorithm such as the ques method. Note that the direction of arrival estimated by the direction of arrival estimation unit 310 is expressed in a local coordinate system with the flying object 20 as a reference.

(Reception directivity calculation section)
The reception directivity calculation unit 320 calculates complex weights for forming directivity in which a beam is directed toward the radio base station 10 and a null is directed toward the interference wave source 30. The complex weight is a weight that adjusts the phase and amplitude of the received signal from each element antenna. For example, a DCMP (Directionally Constrained Minimization of Power) method is used for the directivity calculation. Note that the reception directivity calculation unit 320 uses the position information of the wireless base station 10 and the interference wave source 30 stored in the storage unit 350, the attitude angle information and position information of the aircraft 20 supplied from the flight control unit 224, etc. Based on this, the direction of the wireless base station 10 and the direction of the interference wave source 30 may be specified.

(Reception processing unit)
The reception processing section 330 has a function of combining received signals from each element antenna by multiplying the complex weights obtained by the reception directivity calculation section 320, and a function of decoding the combined received signal according to a communication protocol. The reception processing section 330 outputs the received data obtained by decoding to the flight control section 224.

(Arriving wave source position estimation unit)
The incoming wave source position estimating unit 340 is an example of a position estimating unit that estimates the position of the incoming wave source that is the transmission source of the radio signal received by the aircraft 20. Specifically, the arriving wave source position estimation section 340 converts the direction of arrival in the local coordinate system estimated by the direction of arrival estimation section 310 into an absolute coordinate system based on the center of gravity of the earth. Then, the incoming wave source position estimating unit 340 estimates the position of the incoming wave source using the method of intersection, for example, using the direction of arrival in the absolute coordinate system obtained based on the radio signals received by the aircraft 20 at a plurality of different positions. Then, the estimation result is stored in the storage unit 350. Note that the incoming wave source position estimating unit 340 may estimate the position of the incoming wave source using information on the direction of arrival acquired through communication with the wireless base station 10. Furthermore, if location information indicating the location of an incoming wave source such as the wireless base station 10 is stored in the storage unit 350 in advance, the process of estimating the location of the incoming wave source can be omitted. A more detailed method by which the incoming wave source position estimator 340 estimates the position of the incoming wave source will be described later with reference to FIG. 7.

(Storage part)
The storage unit 350 stores various information used for the operation of the aircraft 20. For example, the storage unit 350 indicates the direction of arrival in the absolute coordinate system obtained by the incoming wave source position estimation unit 340 based on reception of the radio signal, and the position within the aircraft 20 at the time the radio signal was received. Remember information. Furthermore, the storage unit 350 stores incoming wave source position information indicating the position of the incoming wave source estimated by the incoming wave source position estimating unit 340. In addition to the radio base station 10, the incoming wave sources may include the interference wave source 30A and the interference wave source 30B.

(Transmission direction calculation section)
The transmission direction calculation unit 360 is an example of a direction calculation unit that calculates the direction in which the communication partner is located (transmission direction) and the direction in which the interference wave source is located (target direction). For example, when a transmission request to the radio base station 10 is input from the flight control unit 224, the transmission direction calculation unit 360 acquires the position information of the radio base station 10, the interference wave source 30A, and the interference wave source 30B from the storage unit 350. , based on this position information and the position information and attitude angle of the aircraft 20 inputted from the flight control unit 224, calculate the azimuth of the wireless base station 10, the azimuth of the interference wave source 30A, and the azimuth of the interference wave source 30B. Here, the transmission azimuth calculation unit 360 may estimate the position and attitude angle at the time of transmitting the wireless signal, and calculate each azimuth based on the position and attitude angle. The transmission azimuth calculation unit 360 can estimate the position and attitude angle at the time of transmitting the radio signal based on the moving speed data and angular velocity data of the flying object 20. A more detailed method of calculating the transmission direction by the transmission direction calculation section 360 will be described later with reference to FIG.

(Fluctuation prediction department)
The fluctuation prediction unit 370 functions as an acquisition unit that acquires attitude change information regarding the attitude change of the flying object 20, and a transmission control unit that controls directional transmission according to the attitude change information. When the attitude variation of the flying object 20 is large, as described above, the estimation accuracy of the position and attitude angle of the flying object 20 at the time of transmitting the radio signal becomes low, and as a result, there is a possibility that the error in the calculation result of each direction becomes large. . Therefore, the variation prediction unit 370 may calculate adjustment weights for increasing the angular spread of the beam toward the transmission direction and the angular spread of the null toward the target direction based on the attitude change information. Alternatively, the fluctuation prediction unit 370 may stop transmitting the wireless signal when the attitude fluctuation of the flying object 20 exceeds a predetermined standard. There are various methods for controlling directional transmission by the fluctuation prediction unit 370.

(Transmission directivity calculation section)
The transmission directivity calculation unit 380 is a calculation unit that calculates complex weights for imparting directivity to radio signals from the array antenna 252 to the wireless base station 10. The transmission directivity calculation section 380 acquires the transmission direction in which the wireless base station 10 is located and the target direction in which the interference wave source 30 is located from the transmission direction calculation section 360, and determines whether the beam is oriented with respect to the transmission direction and there is no null in the target direction. Complex weights are calculated to form a directivity. Here, when the transmission directivity calculation unit 380 is supplied with adjustment weights for adjusting the angular spread of beams and nulls from the fluctuation prediction unit 370, the transmission directivity calculation unit 380 calculates complex weights by taking the adjustment weights into consideration.

(Transmission processing unit)
The transmission processing unit 390 modulates the transmission data according to a communication protocol and creates a baseband signal. Then, the transmission processing section 390 multiplies the baseband signal by the complex weight calculated by the transmission directivity calculation section 380, and outputs the transmission signal obtained by the multiplication to the RF transmission circuit 258.

<4. Operation of the aircraft>
The configuration of the flying object 20 according to an embodiment of the present invention has been described above. Next, an outline of the operation of the flying object 20 will be summarized with reference to FIGS. 5 and 6.

FIG. 5 is a flowchart showing an outline of the operation of the aircraft 20. When the aircraft 20 starts up, the radio control device 250 acquires the initial value of the position information of the incoming wave source and stores it in the storage unit 350 (S1). The initial value of the position information may be position information of an incoming wave source estimated in the past, or may be position information of a known incoming wave source provided from the wireless base station 10.

The flight control unit 224 then determines whether the initial sequence is being executed (S2). If the initial sequence is being executed (S2/Yes), the flight control unit 224 controls the drive device 230 to change the position of the flying object 20 in order to acquire the surrounding radio wave environment (S3). At this time, at each position of the aircraft 20, the arrival direction estimation section 310 estimates the arrival direction of the radio signal, and the arrival wave source position estimation section 340 estimates the position of the arrival wave source. Since three or more positioning points are required to estimate the position from the direction of arrival, the flying object 20 can estimate the position by repeatedly estimating the direction of arrival of the radio signal while changing the altitude or position in stages. Get the information you need. After the initial sequence ends (S2/No), the flight control unit 224 controls the flight of the aircraft 20 according to the movement plan information (S17). Note that the movement plan information may be updated upon receiving a command from the wireless base station 10.

When there is a data transmission request from the flight control unit 224 (S4/Yes), the communication control unit 300 executes a transmission process to be described later (S5).

Further, the communication control unit 300 receives input of a received signal from the RF receiving circuit 254 (S6), and determines whether or not a wireless signal is received (S7). If no wireless signal is received, the process from S2 is repeated (S7/No). If a wireless signal is received, the processing from S8 to S12 and the processing from S13 to S16 are performed in parallel, and then the processing from S2 is repeated (S7/Yes).

Regarding the processing in S8 to S12, specifically, the direction of arrival estimating unit 310 estimates the direction of arrival of the radio signal from the received signal from each element antenna (S8). Since the direction of arrival estimated here is a direction in a relative coordinate system based on the flying object 20, the arriving wave source position estimation unit 340 converts the direction of arrival into an absolute coordinate system based on the center of gravity of the earth ( S9). Then, the incoming wave source position estimating unit 340 estimates the position of the incoming wave source using the method of intersection, for example, using the direction of arrival in the absolute coordinate system obtained based on the radio signals received by the aircraft 20 at a plurality of different positions. (S11). Further, the incoming wave source position estimating unit 340 updates the incoming wave source position information stored in the storage unit 350 with the incoming wave source position information estimated in S11 (S12).

Regarding the processing in S13 to S16, specifically, when the received radio signal is a radio signal transmitted from the radio base station 10 (S13/Yes), the reception directivity calculation unit 320 Complex weights are calculated to form directivity in which the beam is directed toward the interference wave source 30 and the null is directed toward the interference wave source 30 (S14). Then, the reception processing unit 330 combines the received signals from each element antenna by multiplying them by the complex weights obtained by the reception directivity calculation unit 320, and decodes the combined received signals according to the communication protocol (S15). The received data obtained by decoding is output to the flight control unit 224 (S16).

Next, the transmission process shown in S5 will be explained with reference to FIG.

FIG. 6 is a flowchart showing the transmission process. In the transmission process, first, the variation prediction unit 370 predicts the attitude variation (S17). In the process of the fluctuation prediction, if the transmission of the wireless signal is stopped (S18/No), the process of S17 is looped until the wireless signal can be transmitted. If it is determined that it is possible to transmit a wireless signal (S18/Yes), the transmission direction calculation unit 360 acquires the position information of each incoming wave source from the storage unit 350 (S19), and directs the aircraft 20 to each incoming wave source. The direction is calculated (S20).

Then, the transmission directivity calculation unit 380 calculates complex weights based on the direction of each incoming wave source so that a directivity is formed in which the beam is directed toward the radio base station 10 and the null is directed toward the interference wave source 30 (S21). . Subsequently, the transmission processing unit 390 modulates the transmission data according to the communication protocol to create a baseband signal. Then, the transmission processing section 390 multiplies the baseband signal by the complex weight calculated by the transmission directivity calculation section 380, and outputs the transmission signal obtained by the multiplication to the RF transmission circuit 258 (S22).

(Coordinate transformation)
Next, the coordinate transformation shown in S9 of FIG. 5 will be explained in more detail with reference to FIG.

FIG. 7 is a flowchart showing the flow of coordinate transformation. As shown in FIG. 7, the incoming wave source position estimating unit 340 first obtains the estimation result of the direction of arrival of the radio signal from the direction of arrival estimating unit 310 (S31), and obtains the attitude angle of the aircraft 20 from the flight control unit 224. (S33). Attitude angle is expressed by roll, pitch, and yaw. Let the angle around the z-axis be the yaw angle (azimuth angle), and let the azimuth where the yaw angle is 0 degrees be the x-axis direction. The rotation order is zyx.

Then, the incoming wave source position estimating unit 340 takes the center position of the antenna surface of the array antenna 252 as the origin, and calculates four points (P1 to P1 to P4) is defined. This point will be specifically explained with reference to FIG.

FIG. 8 is an explanatory diagram showing four points defined on the antenna plane. As shown in FIG. 8, P1 and P2 constitute a first set separated on the y-axis, and P3 and P4 constitute a second set separated on the z-axis. Based on the center position O(0,0,0) of the antenna surface, the positions of each point are P1=(0,a,0), P2=(0,-a,0), P3=(0,0 ,a), P4=(0,0,-a). a is 1/4 or more of the wavelength of the radio wave. Note that if the four points have already been defined, there is no need to define the four points anew in S35. Further, the definition of the four points may be performed in the flow of calculation of the transmission direction, which will be described later.

Further, FIG. 8 shows a position reference point BP. The position reference point BP is the antenna position of the positioning sensor of the flying object 20, and has (Bx, By, Bz) as an offset with respect to the center position O (0, 0, 0) of the antenna surface of the array antenna 252. There is. The absolute position of the antenna of the positioning sensor obtained by the positioning sensor is expressed as GP (Gx, Gy, Gz).

Returning to the explanation of the flow of coordinate transformation with reference to FIG. 7, the incoming wave source position estimating unit 340 uses the estimation result of the direction of arrival of the radio signal acquired in S31 and the attitude angle of the flying object 20 acquired in S33. , the absolute position of the incoming wave source is estimated (S37). To this end, the arriving wave source position estimating unit 340 first estimates the relative position Pt of the arriving wave source as viewed from the antenna plane. Assuming that the DOA (direction of arrival estimation processing) result at time T is (θ,φ), the distance between the incoming wave source and the center position O of the antenna plane is R, and the point P = (R,0,0), the incoming wave source The relative position Pt of is expressed as follows. Note that FIG. 9 also illustrates the relationship between the DOA results (θ, φ), the point P, and the relative position Pt of the arriving wave source.

Pt=roty(φ)rotz(θ)P
(Formula 1)

Further, the arriving wave source position estimating unit 340 converts the above-mentioned relative position Pt of the arriving wave source into an absolute position Ptx in the absolute coordinate system. Specifically, if the attitude angle of the aircraft 20 at time T is (θx, θy, θz) and the position information of the aircraft 20 (positioning sensor antenna) is GP (Gx, Gy, Gz), then the incoming wave source is The absolute position Ptx is expressed as follows.

Ptx=rotx(θx)roty(θy)rotz(θz)Pt＋GP-rotx(θx)roty(θy)rotz(θz)BP
(Formula 2)

Note that the distance R between the incoming wave source and the center position O of the antenna plane can be estimated by, for example, the intersection method, using the direction of arrival of the radio signal estimated at multiple times (preferably three or more) and multiple positions. be. Until the estimation results of the directions of arrival of radio signals at multiple points in time are obtained, the distance R between the incoming wave source and the center position O of the antenna plane is assumed to be a sufficiently large value, and the above-mentioned relative position Pt of the incoming wave source is assumed to be substantially In other words, it indicates the relative direction of the incoming wave source. In this case, it can be said that the first term on the right side of Equation 2 indicates the absolute direction of the arriving wave source expressed with respect to the direction of gravity. The incoming wave source and antenna are determined based on the absolute direction of the incoming wave source, position information GP (Gx, Gy, Gz), position reference point BP (Bx, By, Bz), and attitude angle (θx, θy, θz) at multiple points in time. After the distance to the center position O of the surface is estimated, the estimated distance is applied to the distance R.

Then, the storage unit 350 stores the absolute position Ptx of the arriving wave source estimated in S37 (S39).

(Calculation of transmission direction)
Next, the transmission direction calculation shown in S20 of FIG. 6 will be explained in more detail with reference to FIG.

FIG. 10 is a flowchart showing the flow of calculating the transmission direction. First, the transmission azimuth calculation unit 360 reads the absolute position Ptx of the incoming wave source from the storage unit 350 (S41). Then, the transmission azimuth calculation unit 360 acquires the current (time T+Δt) attitude angle of the flying object 20 from the flight control unit 224 (S43). Subsequently, the transmission azimuth calculation unit 360 calculates the current absolute positions P1d to P4d of the four points defined on the antenna plane (S45). In FIG. 11, as the attitude angle of the aircraft 20 changes from time T, the x-axis, y-axis, and z-axis indicated by broken lines change to the x'-axis, y'-axis, and z' indicated by solid lines, respectively. It is shown that the axis has changed and the absolute positions of the four points have also changed. The absolute positions P1d to P4d after this movement are expressed as follows, where the current attitude angle of the flying object 20 is (θxd, θyd, θzd) and the position information is GPd (Gxd, Gyd, Gzd).

P1d=rotx(θxd)roty(θyd)rotz(θzd)P1+GPd-rotx(θxd)roty(θyd)rotz(θzd)BP
P2d=rotx(θxd)roty(θyd)rotz(θzd)P2+GPd-rotx(θxd)roty(θyd)rotz(θzd)BP
P3d=rotx(θxd)roty(θyd)rotz(θzd)P3+GPd-rotx(θxd)roty(θyd)rotz(θzd)BP
P4d=rotx(θxd)roty(θyd)rotz(θzd)P4+GPd-rotx(θxd)roty(θyd)rotz(θzd)BP
(Formula 3)

Thereafter, the transmission azimuth calculation unit 360 calculates the current relative azimuth of the incoming wave source using the absolute positions P1d to P4d obtained above and the absolute position Ptx of the incoming wave source read in S41 (S47). Specifically, from the path difference information between the path between the absolute position P1d and the absolute position Ptx of the arriving wave source, and the path between the absolute position P2d and the absolute position Ptx of the arriving wave source, the It is possible to calculate the yaw angle θ' at the current position of the arriving wave source. Also, from the path difference information between the path between the absolute position P3d and the absolute position Ptx of the incoming wave source and the path between the absolute position P4d and the absolute position Ptx of the incoming wave source, the current incoming wave as seen from the antenna surface is determined. It is possible to calculate the pitch angle φ' at the position of the wave source.

Note that when focusing on the radio base station 10 as the incoming wave source, the relative direction of the incoming wave source corresponds to the transmission direction, and when focusing on the interference wave source 30 as the incoming wave source, the relative direction of the incoming wave source corresponds to the transmission direction. Corresponds to direction.

<5. Effect>
According to the embodiment of the present invention described above, various effects can be obtained. For example, according to an embodiment of the present invention, even if the attitude or position of the flying object 20 changes from the estimated time of the arrival direction of the radio signal, it is possible to calculate the relative orientation of the arriving wave source at that time. . Therefore, it is possible to more effectively reduce interference with other wireless systems such as the interference wave source 30A and the interference wave source 30B. As a result, it is possible to suppress deterioration in communication quality in other wireless systems. Further, it is possible to realize smooth communication with the wireless base station 10 that is the communication partner.

Further, according to an embodiment of the present invention, even if the absolute position of each incoming wave source is not known, the direction of arrival of the radio signal, the attitude angle (θx, θy, θz) of the aircraft 20, and the position at multiple points in time can be determined. It is possible to estimate the absolute position of each arriving wave source based on information GP (Gx, Gy, Gz), position reference point BP (Bx, By, Bz), etc.

Further, according to an embodiment of the present invention, the four points defined on the antenna plane are P1=(0,a,0), P2=(0,−a,0), P3=(0,0 ,a), P4=(0,0,-a), where a is 1/4 or more of the wavelength of the radio wave. Therefore, the distance between points P1 and P2 on the y-axis is more than 1/2 of the wavelength of the radio wave, and the distance between points P3 and P4 on the z-axis is also more than 1/2 of the wavelength of the radio wave. Become. By using the positions of these four points, it is possible to appropriately calculate the relative orientation of the arriving wave source.

Note that, like the interference wave source 30B, it is also assumed that the interference partner or the communication partner is a mobile body. In that case, strictly speaking, the absolute position Ptx of the interference partner is not constant. However, if the distance R between the flying object 20 and the interference partner is sufficiently large, the influence of the movement of the interference partner on the calculation result of the relative azimuth is limited. In addition, the more frequently the interfering party transmits wireless signals, the more frequently the interfering party's absolute position will be updated, so in this case as well, the influence of the interfering party's movement on the calculation results of the relative direction is limited. It is believed that there is.

<6. Supplement>
Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

For example, in the above explanation, other wireless communication systems (interference wave reduction 30A and interference wave source B) are used as interference wave sources, but a single interference wave source may be used. For example, a power generation facility or an aircraft radar device may serve as the interference wave source 30 alone. At this time, the moving body 20 may store the absolute coordinate positions of the facility and device in advance in the storage unit 350. At that time, the position information may be used as the position of the incoming wave source acquired in S19. Furthermore, three or more interference wave sources 30 may exist.

Moreover, although the example in which four points are defined on the antenna surface has been described above, the number of points defined on the antenna surface may be three. That is, in the above example, two points separated on the y-axis and two points separated on the z-axis are different, but two points separated on the y-axis and two points separated on the y-axis are different. Three points may be defined, consisting of one of the two points and one point spaced apart on the z-axis. Even in this case, it is possible to calculate the relative orientation of the arriving wave source according to the method described above.

Further, each step in the processing of the aircraft 20 in this specification does not necessarily need to be processed in chronological order in the order described as a sequence diagram or a flowchart. For example, each step in processing the aircraft 20 may be processed in a different order from the order described in the flowchart, or may be processed in parallel.

It is also possible to create a computer program for causing hardware such as a CPU, ROM, and RAM built into the aircraft 20 to exhibit functions equivalent to the respective configurations of the aircraft 20 described above. Also provided is a non-transitory storage medium on which the computer program is stored.

10 Wireless base station 20 Aircraft 220 Flight control device 222 Sensor group 224 Flight control unit 230 Drive device 240 Battery 250 Radio control device 252 Array antenna 254 RF receiving circuit 258 RF transmitting circuit
300 Communication control section 310 Direction of arrival estimation section 320 Reception directivity calculation section 330 Reception processing section 340 Arrival wave source position estimation section 350 Storage section 360 Transmission direction calculation section 370 Fluctuation prediction section 380 Transmission directivity calculation section 390 Transmission processing section 30 Interference wave source

Claims (8)

A mobile object,
a storage unit that stores position information of the radio wave source;
array antenna,
an attitude angle acquisition unit that obtains an attitude angle of the moving body;
a first set of at least three points defined on the antenna plane of the array antenna, the two points being spaced apart in a first direction; and a first set of two points being spaced apart in a second direction orthogonal to the first direction; calculating the position of each of the at least three points having a second set of two points based on the attitude angle of the moving body;
Path difference information between each of the two points of the first set and the position indicated by the position information of the radio wave source, and each of the two points of the second set and the position indicated by the position information of the radio wave source. an azimuth calculation unit that calculates the azimuth of the radio wave source based on the path difference information;
a calculation unit that calculates a complex weight for giving directivity to communication in the array antenna based on the direction of the radio wave source;
A mobile object equipped with. The mobile body is
Further comprising a positioning sensor that has a positioning antenna and performs positioning based on a signal received by the positioning antenna,
The mobile body according to claim 1, wherein the azimuth calculation unit calculates the position of each of the at least three points based on position information obtained by the positioning sensor in addition to the attitude angle of the mobile body. . The mobile body is
a direction estimation unit that estimates a relative direction of the radio wave source as viewed from the antenna surface based on signals received from the radio wave source by each antenna element constituting the array antenna;
The relative direction of the radio wave source is converted into an absolute direction based on the direction of gravity based on the attitude angle of the moving object, and the absolute direction of the radio wave source obtained at a plurality of times and the positioning at the plurality of times are determined. The mobile object according to claim 2, further comprising a position estimation unit that estimates position information of the radio wave source based on position information obtained by a sensor. The calculation unit calculates a complex weight for giving directivity such that a beam is directed toward the radio wave source when the radio wave source is a communication partner, and calculates a complex weight for giving the radio wave source directivity such that the beam is directed to the radio wave source when the radio wave source is an interference partner. The moving object according to any one of claims 1 to 3, which calculates complex weights for giving directionality such that a null points toward a source. Each of the two points of the first set is separated by a distance of 1/2 wavelength or more of a radio wave in the first direction,
4. The moving body according to claim 1, wherein each of the two points of the second set is separated by a distance of 1/2 wavelength or more of a radio wave in the second direction. The at least three points consist of two points included in the first set and two points included in the second set that are different from the two points included in the first set. , four points. A method performed by a mobile object having an array antenna, the method comprising:
Memorizing the location information of the radio wave source,
a first set of at least three points defined on the antenna plane of the array antenna, the two points being spaced apart in a first direction; and a first set of two points being spaced apart in a second direction orthogonal to the first direction; calculating the position of each of the at least three points having a second set of two points based on the attitude angle of the moving body;
Path difference information between each of the two points of the first set and the position indicated by the position information of the radio wave source, and each of the two points of the second set and the position indicated by the position information of the radio wave source. calculating the direction of the radio wave source based on the path difference information;
Calculating complex weights for giving directivity to communication in the array antenna based on the direction of the radio wave source;
including methods. For mobile objects with array antennas,
Memorizing the location information of the radio wave source,
a first set of at least three points defined on the antenna plane of the array antenna, the two points being spaced apart in a first direction; and a first set of two points being spaced apart in a second direction orthogonal to the first direction; calculating the position of each of the at least three points having a second set of two points based on the attitude angle of the moving body;
Path difference information between each of the two points of the first set and the position indicated by the position information of the radio wave source, and each of the two points of the second set and the position indicated by the position information of the radio wave source. calculating the direction of the radio wave source based on the path difference information;
Calculating complex weights for giving directivity to communication in the array antenna based on the direction of the radio wave source;
A program to run.

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