JP6755481B2 - Tracking antenna system, projectile and tracking antenna device - Google Patents

Description

The present invention relates to a flying object, a tracking antenna device for tracking a flying object, and a tracking antenna system.

In the event of a disaster such as an earthquake or fire, the site is photographed by a camera mounted on an unmanned airplane or helicopter (shooting helicopter) as an initial response by private news media and government agencies, and the captured video information is quickly real-time. In some cases, a technology such as transmission to a ground station may be adopted. Since such video information is important information that serves as a judgment source for the initial response, it is required to transmit the video information at any time without interruption.

As a method of tracking a flying object represented by an unmanned aerial vehicle, it is transmitted by GPS (Global Positioning System), which has become widespread in recent years, and an on-board wireless communication device, and it is received on the ground side using a tracking antenna. By continuing, it is becoming common to secure wireless communication links.

However, in this case, when the antenna on the flying object side is a low-gain omnidirectional antenna, the flying object information obtained by wireless communication is GPS information, so the content of the information is limited to the position and speed. There is.

On the other hand, for example, Patent Document 1 discloses an antenna-oriented control device that can reliably capture a tracking target even when mounted on an air vehicle that moves at high speed and is accompanied by a sudden change of direction. In the technique described in Patent Document 1, the position information detection unit mounted on the air vehicle detects the current position of the air vehicle (GPS receiving device). The azimuth detection unit detects the horizontal azimuth of the flying object (geomagnetic sensor). The latitude and longitude of the base station to be tracked are registered in advance in the base station position information source. The antenna azimuth calculation unit calculates the position and azimuth at which the flying object is currently facing. The base station azimuth calculation unit calculates an azimuth vector to be directed from the aircraft to the target base station from the position information detection unit and the base station position information source. The target azimuth calculation unit calculates the angle at which the currently facing antenna should rotate. The antenna azimuth control unit controls the antenna azimuth drive unit so that the directional antenna points at the angle calculated by the target azimuth calculation unit.

Further, Patent Document 2 discloses a configuration in which video information transmitted from a transmitting unit of a photographing helicopter is relayed by another helicopter (relay helicopter) and transmitted to a terrestrial receiving station. As a result, the shooting cover area is expanded, and transmission to a ground station at a distance of, for example, about 200 km is possible. In the technique of Patent Document 2, transmission data sd is transmitted from the information transmitter of the camera via the antenna, and the transmission data sd is received by the relay transmitter of the repeater via the antenna to be a ground station. It is relayed to. In the information transmission device, the camera data sa indicating the flight state of the camera is transmitted to the repeater, and the repeater data sb representing the flight state is acquired from the repeater, and the camera data sa and the repeater data sb are used. Based on this, the direction characteristics of the antenna, the modulation method of the transmission data sd, and the output level are adaptively controlled.

Japanese Unexamined Patent Publication No. 2002-261526 JP-A-2009-239758

Inoue et al., Marine Antenna System for Realization of Next Generation Broadband, Journal of the JIME vol.41, No.6 (2006)

As described above, when the antenna on the flying object side is a low-gain omnidirectional antenna, it is inevitable that a high-gain, that is, a relatively large-scale tracking antenna will be prepared on the ground side for transmission and reception. Although the unmanned aircraft itself, which is expected to be used for various purposes, is small and low in cost, there is a problem that high-speed transmission cannot be performed without using a large-scale tracking antenna in developing various uses.

Further, the antenna directivity control device described in Patent Document 1 controls the directivity of the antenna within the tracking performance of the drive unit on the premise that the other side is a base station, and the tracking performance of the drive unit. If it exceeds, it cannot be dealt with. Further, there is a problem that the antenna device on the flying object side, which is originally desirable to be smaller and lighter, causes an increase in size or weight.

Further, in the technique described in Patent Document 2, although the photographing cover area is expanded, a repeater is required in addition to the photographing machine. Moreover, not only is it necessary for the aircraft to have a configuration for controlling the directivity of the antenna, but also high capture accuracy is a prerequisite for the control process between the camera and the repeater. However, since high capture accuracy is not always achieved in actual operation, there are restrictions on the environment in which it can be operated.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide equipment on the flying object side and the ground station side in a configuration in which a signal from a flying object is received while being tracked by a ground station. It is to provide a tracking antenna system, a flying object, and a tracking antenna device capable of reducing the weight and simplification of the above.

Preferably, each ground station comprises a received signal strength measuring means for measuring the received signal strength of the signal from the flying object and transmitting the signal to the control station, and the control station further comprises the received signal strength. and based on said position of the flying object information of the measurement information, using the freedom space propagation loss between the projectile and the tracking antenna, constantly calculating the likelihood that a desired frequency bandwidth can not be secured However, before it becomes impossible to secure, tracking for controlling the handover process of switching to the tracking antenna that can secure the required frequency bandwidth from among the plurality of tracking antennas deployed in each of the ground stations. Includes antenna control means.
Preferably, each of the projectiles comprises a received signal strength measuring means for measuring the received signal strength of the signal from the ground station and transmitting the signal to the ground station, and the control station further comprises the received signal strength from the ground station. based on the position information of the flying object of the measurement information and the received signal strength transmitted, using the freedom space propagation loss between the projectile and the tracking antenna, the desired frequency bandwidth secured A handover that constantly calculates the possibility that it will not be possible and switches to a tracking antenna that can secure the required frequency bandwidth from among the plurality of tracking antennas that are deployed at each ground station before it becomes impossible to secure it. Includes tracking antenna control means for controlling processing.

Preferably, the control station in accordance with the measurement information that will be transmitted from the ground station, currently, when the gain of the aircraft antenna during communication becomes a predetermined level or less, the gain is higher aircraft antenna than the current aircraft antenna If it exists, select the aircraft antenna.

Preferably, each ground station comprises a received signal strength measuring means for measuring the received signal strength of the signal from the projectile and transmitting it to the control station, and the control station further flies the received signal strength and the measurement information. Based on the body position information, the free space propagation loss between the tracking antenna and the projectile is used to constantly calculate the possibility that the desired frequency bandwidth cannot be secured, and before it becomes impossible to secure it. , A tracking antenna control means for controlling a handover process of switching to a tracking antenna capable of securing a required frequency bandwidth from a plurality of tracking antennas respectively deployed in each ground station .
Preferably, each projectile comprises a received signal strength measuring means for measuring the received signal strength of the signal from the ground station and transmitting it to the ground station, and the control station further comprises a received signal transmitted from the ground station. Based on the intensity and the information on the position of the projectile in the measurement information, the possibility that the desired frequency bandwidth cannot be secured is constantly calculated and secured by using the free space propagation loss between the tracking antenna and the projectile. Includes a tracking antenna control means for controlling the handover process of switching from a plurality of tracking antennas deployed to each ground station to a tracking antenna capable of securing the required frequency bandwidth before it becomes impossible. ..

Preferably, the plurality of airframe antennas are a plurality of slot antennas each provided in a plurality of predetermined areas.

Preferably, the plurality of airframe antennas further include a plurality of slot antennas, each provided in a plurality of predetermined regions around a second circumference orthogonal to the first circumference of the outer shell of the flying object .

According to the tracking antenna system, the flying object, and the tracking antenna device of the present invention, it is possible to reduce the weight and simplify the equipment on the flying object side and the ground station side.

In addition, it is possible to maintain a stable wireless communication link according to the attitude and position of the flying object.

It is a conceptual diagram which shows the structure of the wireless communication system including the tracking antenna device of this embodiment. It is a figure for demonstrating the structure of the unmanned aerial vehicle 100 of this embodiment. It is a functional block diagram for demonstrating the configuration of the system server 300. It is a figure for demonstrating the concept of processing of the ground station 200 and the system server 300 when tracking an unmanned aerial vehicle 100.1 by a system server 300. It is a flowchart for demonstrating the processing flow of the radio aircraft 100, the ground station 200 and the system server 300.

Hereinafter, a wireless communication system including the tracking antenna device according to the embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the components and processing steps having the same reference numerals are the same or equivalent, and the description thereof will not be repeated if they are not necessary.

In the following, although not particularly limited, for example, a mobile station that is a flying object will be described as being an unmanned aerial vehicle (UAV). However, for example, an unmanned helicopter or a drone may be used.

As will be described below, the wireless communication system of the present embodiment is a wireless communication system composed of a plurality of unmanned aircraft flying in a certain airspace and a tracking antenna on the ground, and a plurality of radio communication systems for tracking an unmanned aircraft from the ground. It is equipped with a tracking antenna. Unmanned aerial vehicles will be equipped with multiple switchable high-gain antennas and hybrid inertial navigation systems. Then, the unmanned aircraft transmits the measured position, speed, and attitude information of the aircraft to the ground, and using this information, the control system (system server) on the ground station side uses the ground tracking antenna to be used and the aircraft. Select a ground tracking antenna and a switchable antenna on the aircraft side to use the antenna so that the specified transmission speed can be maintained.
[Embodiment]
FIG. 1 is a conceptual diagram showing a configuration of a wireless communication system including the tracking antenna device of the present embodiment.

When performing wireless communication in an area with good visibility from a ground station, such as in the air or at sea, the reach can be extended by tracking the mobile station with a high-gain directional antenna.

In the event of a large-scale disaster or accident, it is necessary to capture and obtain information on the area in real time as widely as possible at the same time. In this case, it is necessary to receive images taken by a plurality of unmanned aerial vehicles 10.1 to 100.2 (hereinafter, collectively referred to as "unmanned aerial vehicle 100") on the ground, and therefore, one unmanned aerial vehicle On the other hand, a wireless communication link capable of securing the frequency bandwidth required for high-speed transmission is secured by using one tracking antenna.

In the following, for the sake of simplicity, the number of unmanned aerial vehicles will be described as two, but the number may be larger.

In FIG. 1, the ground station 201 to 200. M (hereinafter, collectively referred to as “ground station 200”) has a tracking antenna device, and can direct the antenna in the direction of the unmanned aerial vehicle 10.1 to 100.2. Ground station 201-200. M is the corresponding directional antenna 10.1-10, respectively. It is assumed that wireless communication is performed with the mobile station by M (M: natural number; hereinafter, collectively referred to as "directional antenna 10"). Directional antenna 10.1-10. The range of directivity of M is shown in FIG. 1 in the beam direction BM. 1-BM. Shown as M. Further, the unmanned aerial vehicle 10.1 to 100.2 includes a high gain antenna 120, which will be described in detail later.

The system server 300 is from an unmanned aerial vehicle 10.1 to 100.2 to a ground station 201 to 200. Position / attitude information of the unmanned aerial vehicle 10.1-100.2 transmitted via M and the ground station 200-1 / 200. Based on the signal strength information of the unmanned aerial vehicle 10.1-100.2 received by M, the wireless communication link capable of securing the frequency bandwidth required for the desired communication is monitored, and as will be described later, the unmanned vehicle is monitored. A ground station that connects and tracks wireless communication with an aircraft 10.1 to 100.2 is a ground station of 2010 to 200. From M, select from time to time and select ground stations, such as ground stations 200.1 and 200. Controls the tracking direction of M.

Ground stations 200.1 and 200. In M, the tracking antenna control units 20.1 and 20., Depending on the control signal in the tracking direction from the system server 300, respectively. M is the drive unit 30.1 and 30. Control and drive M respectively, directional antennas 10.1 and 10. Control the direction of M. As the directivity driving method, for example, the directivity may be driven by a gimbal mechanism having two or more axes, or the directivity may be electronically controlled as an array antenna.
(Structure of unmanned aerial vehicle 100)
As described above, conventionally, unmanned aerial vehicles often use omnidirectional low-gain antennas represented by whip antennas. As a result, by transmitting the information measured from the GPS receiver mounted on the unmanned aerial vehicle to the ground tracking antenna side, the relative and azimuth angles of the target unmanned aerial vehicle are calculated from the positional relationship of the ground tracking antenna, and the target unmanned aerial vehicle is selected. In some cases, it was configured to be able to track.

FIG. 2 is a diagram for explaining the configuration of the unmanned aerial vehicle 100 of the present embodiment.

With reference to FIG. 2, as shown in FIG. 2 (a), around the cylindrical fuselage 110 of the unmanned aerial vehicle 100, an antenna having a higher gain than the whip antenna, for example, a slot antenna 120 to 120.3 ( Hereinafter, when they are generically referred to, they are referred to as "antenna 120"). The slot antenna 120 to 120.3 has an antenna shape that matches the body shape. The number of slot antennas may be more than three.

Here, the "slot antenna" has a width of about 1/2 wavelength and a height of about 1/2 wavelength in the center of a metal plate (or metal foil or net) having a size of about 1/2 wavelength and a width of 3/4 wavelength in the longitudinal direction. It is provided with a slot of about 0.01 wavelength. Power is supplied to two points in the center of the long side of the slot, or to a position slightly offset from the center. It has the same shape as a stack of many loop antennas and has a high gain. In particular, the one having the shape shown in FIG. 2A is called a cylindrical slot antenna in which a metal plate is rolled into a cylindrical shape.

In FIG. 2A, since a part of the fuselage of the unmanned aerial vehicle 100 has a cylindrical shape, a plurality of such cylindrical slot antennas are arranged around the central axis CC'of the cylindrical shape. It has become. Therefore, a plurality of slot antennas can be attached so as to cover the entire circumference of the fuselage of the unmanned aerial vehicle 100, and a higher gain of several dB or more can be achieved around the fuselage axis than the whip antenna.

However, if the projectile has a more general shape, it is not necessarily limited to the configuration in which the projectile is arranged around the cylindrical axis in this way. That is, the slot antenna is capable of receiving radio waves from as many directions as possible, preferably from all directions, or conversely, transmitting radio waves within an aerodynamically acceptable range according to the outer shape of the flying object. Can be arranged. For example, if the outer shell is a spherical drone, a plurality of slot antennas are provided in a predetermined plurality of regions around the first circumference of the outer shell (for example, a horizontal circumference in a steady state), and the first is provided. It is also possible to provide a plurality of slot antennas in a predetermined plurality of regions around the second circumference orthogonal to the circumference.

In an unmanned aerial vehicle in which air resistance has a great influence on flight, it is desirable to provide a plate-shaped antenna such as a slot antenna so as to cover the fuselage of the aircraft as described above. However, when the influence of the air resistance of the aircraft is relatively low like a drone, a linear antenna such as a monopole or dipole antenna is provided so as to protrude from the aircraft, and multiple antennas are combined to form the antenna from the aircraft. It is also possible to configure it so that a gain of a predetermined value or more can be secured in all directions.

FIG. 2B is a functional block diagram of the unmanned aerial vehicle 100.

The unmanned aerial vehicle 100 includes an antenna 120 having a configuration as shown in FIG. 2A, a high-frequency switch 124 for selecting an antenna to be used for a wireless link among the antennas of the antenna 120, and the selected antenna. A hybrid navigation device including a radio unit 122 for communication, an on-board computer 128 for controlling the flight of the unmanned aerial vehicle 100 and controlling communication, and a GPS and a gyro for measuring the position and attitude of the unmanned aerial vehicle 100. Includes 126 and an image pickup device 130 for capturing images (still images, moving images) from the sky.

Regarding the high frequency switch 124, in order not to generate a loss due to switching, for example, a high frequency relay or a semiconductor switch is used, and the antenna is switched according to the instruction of the on-board computer 128.

The position, speed, attitude angle (yaw angle, roll angle, pitch angle), and attitude angular velocity information of the unmanned aerial vehicle 100 measured by the hybrid navigation system 126 are measured as measurement information from the selected antenna to the ground station. For example, it is transmitted at regular time intervals. Further, according to the instruction from the ground station, the image data captured by the imaging device 130 is also transmitted to the ground station from the selected antenna in the same manner.

The radio unit 122 measures the information on the received radio wave intensity from the selected antenna 120, transmits it from the selected antenna to the ground station 200 according to the control of the on-board computer 128, and further, the received radio wave intensity. The information may be transmitted from the ground station 200 to the system server 300. Alternatively, the received radio field strength of the signal from the unmanned aerial vehicle 100 may be measured by the ground station 200, and the information on the received radio wave strength may be transmitted from the ground station 200 to the system server 300. Hereinafter, it will be described as assuming that the received radio wave intensity is measured on the ground station 200 side.

As a method of selecting a specific antenna from the antenna 120 by the high frequency switch 124, for example, one of the following methods can be used, or the control mode can be switched as needed. ..

1) Multiple antennas 120 to 120 by control from the ground station 200. From L (L: natural number), the antenna having the highest gain is selected at any time as a wireless link to the ground station 200. Note that this control may be performed autonomously on the unmanned aerial vehicle side by the on-board computer 128 instead of being controlled by the ground station by having the unmanned aerial vehicle 100 side store information on the position of the ground station in advance.

2) Multiple antennas 120 to 120 by control from the ground station. Among L (L: natural number), as a wireless link to the ground station, there is an antenna having a higher gain than the current antenna when the gain of the antenna currently in communication falls below a predetermined level. When, select the antenna. Note that this control may also be performed autonomously on the unmanned aerial vehicle side by the on-board computer 128, instead of being controlled by the ground station.

In the following description, it is assumed that the antenna having the highest gain is selected at any time by the control from the ground station.

Therefore, the selection of the high gain antenna is executed by a command from the ground, and it is assumed that only one of the plurality of high gain antennas selected as the antenna having the highest gain is used. .. Here, as the "antenna having the highest gain", for example, the antenna having the highest gain is selected from the expected angles estimated from the position, attitude, and speed of the unmanned aerial vehicle 100 when viewed from the tracking antenna on the ground. Can be.

FIG. 3 is a functional block diagram for explaining the configuration of the system server 300. The system server 300 is configured in the same manner as a well-known computer system, and an arithmetic unit such as a CPU (Central Processing Unit) performs arithmetic processing based on a program stored in the storage device, as shown in FIG. Each function shall be executed.

The system server 300 and a communication interface (hereinafter, communication I / F) 302 for communicating with the ground station 200 (in FIG. 3, exemplarily showing the ground stations 200.m-1 and 200.m). , The position / attitude information acquisition unit 304 that acquires the position, speed, attitude angle, and attitude angular velocity information of the unmanned aerial vehicle 100 transmitted from the unmanned aerial vehicle 100 and received and transmitted by the ground station 200, and the position / attitude information acquisition. Based on the information from the unit 304, each of the ground stations 200 includes a tracking direction control unit 306 that generates a tracking direction control signal for controlling the tracking direction of the unmanned aerial vehicle 100. The tracking direction control unit 306 uses information such as the position, speed, attitude angle, and attitude angle speed of the unmanned aerial vehicle 100 transmitted from the unmanned aerial vehicle 100 side in order to select the antenna 120 having a high gain in the unmanned aerial vehicle 100. Therefore, an instruction to select the antenna having the maximum gain from the relative attitude angle with the ground tracking antenna 10 in charge of tracking is also generated as a tracking direction control signal. The tracking direction control signals are transmitted to the corresponding ground stations 200, respectively.

The system server 300 further uses the signal strength information acquisition unit 304 that acquires information on the received signal strength of the communication between the ground station 200 and the unmanned aircraft 100 from the ground station 200, and the information from the signal strength information acquisition unit 304. The unmanned aircraft 100 is provided with a tracking antenna control unit 312 that generates a tracking antenna change instruction signal for controlling selection of a ground station equipped with a tracking antenna that is in charge of tracking the unmanned aircraft 100. The tracking antenna change instruction signal is transmitted to the corresponding ground station 200, respectively.

The tracking antenna control unit 312 uses the value of the free space propagation loss that is transmitted from the unmanned aircraft 100 and can be calculated from the intensity of the radio wave received by the ground tracking antenna 10 and the GPS position information, etc., to obtain a desired frequency bandwidth. A process for constantly calculating the possibility that it cannot be secured and switching to a tracking antenna that can secure the required frequency bandwidth among the plurality of tracking antennas 10 deployed in the ground station 200 before it cannot be secured. To execute.

The system server 300 further includes an imaging data acquisition unit 320 that receives imaging information from the unmanned aerial vehicle 100 via the ground station 200, and a storage device 322 for storing the acquired imaging data.

The system server 300 may be installed as one server for centralized management of a combination of a plurality of unmanned aerial vehicles 100 and a plurality of tracking antennas 10, or may be configured by a plurality of distributed servers. Good.

FIG. 4 is a diagram for explaining the concept of processing of the ground station 200 and the system server 300 when tracking the unmanned aerial vehicle 100.1 by the system server 300.

Further, FIG. 5 is a flowchart for explaining a processing flow of the radio aircraft 100, the ground station 200, and the system server 300 for executing the concept shown in FIG.

In FIG. 4, the tracking antenna 10. When the unmanned aerial vehicle 100.1 moved from the state where the unmanned aerial vehicle 100.1 was being tracked by m at time t = t1 + Δ, the tracking antenna 10. The m-1 shows the concept of shifting to the state of tracking the unmanned aerial vehicle 100.1.

With reference to FIGS. 4 and 5, first, in the system server 300, the tracking direction control unit 306 generates a tracking direction control signal based on the measurement information received from the unmanned aircraft 100 so far, and the ground If it is transmitted to the station 200 (S100) and the tracking antenna control unit 312 calculates whether it is necessary to change the tracking antenna in charge of tracking (Y in S102), the ground is used as a tracking antenna change instruction. It is transmitted to the station 200 (S104).

As an initial setting, for example, the system server 300 may calculate the tracking direction control signal and the tracking antenna change instruction signal based on the information from all the ground stations 200.

The ground station 200 receives the control signal of the tracking direction control signal and the tracking antenna change instruction signal from the system server 300 (S200), and when the tracking antenna change instruction is given (S202), the ground station 200 is for switching the tracking antenna. The handover process is executed (S204), and the direction of the tracking antenna is controlled in response to the tracking direction control signal (S206).

The ground station 200 further transmits an instruction to select an antenna whose gain satisfies a predetermined condition from the antennas 120 and a control signal instructing the transmission of imaging information to the unmanned aerial vehicle 100 (S208).

In the unmanned aerial vehicle 100, the on-board computer 128 acquires information such as position and attitude from the hybrid completed navigation system (S300), and receives the control signal transmitted from the ground station 200 in S208 (S302).

In the unmanned aerial vehicle 100, further, one of the antennas 120 is selected by the high frequency switch 124 under the control of the on-board computer 128 based on the instruction from the ground station 200 (S304).

Subsequently, the unmanned aerial vehicle 100 transmits information regarding its own position, attitude, and the like to the ground station 200 (S306), and transmits imaging information to the ground station 200 in response to an instruction from the ground station 200. (S308).

On the other hand, the ground station 200 receives information on the position, attitude, etc. from the unmanned aerial vehicle 100 (S210), and also acquires information on the reception strength of the signal from the unmanned aerial vehicle 100 at the ground station 200 (S212). , The image pickup information from the unmanned aerial vehicle 100 is received (S214), and the information received from the unmanned aerial vehicle 100 is transmitted to the system server 300 (S216).

The system server 300 receives the signal transmitted from the ground station 200 in step S216 (S106), and calculates the tracking direction control signal and the tracking antenna change instruction signal for the ground station 200 (S108).

As described above, according to the tracking antenna system, the flying object, and the tracking antenna device of the present embodiment, in the wireless communication between the unmanned aircraft flying in a certain airspace due to the occurrence of a disaster or accident and the ground tracking antenna, the unmanned aircraft side Can select an antenna with the optimum gain to secure a link with a ground-based tracking antenna, regardless of its orientation.

In addition, even on the ground side, it is possible to realize reliable tracking of unmanned aerial vehicles with a small-scale tracking antenna and maintain a wireless communication link capable of high-speed transmission.

The embodiments disclosed this time are examples of configurations for concretely implementing the present invention, and do not limit the technical scope of the present invention. The technical scope of the present invention is indicated by the scope of claims, not the description of the embodiment, and includes modifications within the scope of the wording of the claims and the scope of the equivalent meaning. Is intended.

10.1-10. M directional antenna, 30 to 30. M drive, 100.1, 100.2 unmanned aerial vehicle, 120 antennas, 201-200. M ground station, 122 radio unit, 124 high frequency switch, 126 hybrid inertial navigation system, 128 on-board computer, 130 imaging device, 300 system server, 302 communication I / F, 304 position / attitude information acquisition unit, 306 tracking direction control unit, 310 signal strength information acquisition unit, 312 tracking antenna control unit, 320 imaging data acquisition unit, 322 storage device.

Claims (6)

It is a tracking antenna system
Equipped with multiple projectiles
Each of the plurality of projectiles
Navigation means to grasp one's position , speed, attitude angle and attitude angular velocity ,
A wireless communication means for transmitting the grasped position , speed, attitude angle, and attitude angular velocity as measurement information to the ground station, and
Multiple airframe antennas capable of transmitting and receiving wireless signals in multiple directions,
Includes an antenna selection means for selecting an airframe antenna having a gain satisfying a predetermined condition from a plurality of the airframe antennas for a target wireless communication link.
The plurality of the airframe antennas are provided in a plurality of predetermined regions around the first circumference of the outer shell of the projectile, respectively.
A plurality of ground stations for performing wireless communication with the plurality of projectiles are provided.
Each of the plurality of ground stations
With a directional tracking antenna,
The directivity control means for driving the communication directivity of the tracking antenna in the direction of the corresponding flying object among the plurality of flying objects in response to the tracking control instruction is included.
In addition to generating the tracking control instruction for controlling the communication directivity of the plurality of ground stations, a control station for selecting the airframe antenna is further provided.
The control station monitors a wireless communication link capable of securing a frequency bandwidth between the plurality of ground stations and the plurality of projectiles, and outputs the tracking control instruction to the ground station.
The control station selects the antenna having the highest gain from the plurality of airframe antennas from the prospective angles estimated from the measurement information when viewed from the tracking antenna that tracks the flying object among the ground stations .
The ground station is a tracking antenna system that transmits a signal for indicating the selected airframe antenna to the antenna selection means of the flying object at any time. Prior Symbol control station, according to prior Symbol measurement information that will be transmitted from the ground station, currently, when the gain of the aircraft antenna during communication becomes a predetermined level or less, gain than higher current aircraft antenna body The tracking antenna system according to claim 1, wherein the airframe antenna is selected when an antenna is present. Each of the ground stations includes a received signal strength measuring means for measuring the received signal strength of the signal from the flying object and transmitting the signal to the control station.
The control station is further based on the position information of the flying object of the measurement information and the received signal strength, with freedom space propagation loss between the projectile and the tracking antenna, the desired frequency The possibility that the bandwidth cannot be secured is constantly calculated, and before it becomes impossible to secure, the tracking antenna that can secure the required frequency bandwidth from the plurality of tracking antennas deployed in each of the ground stations. The tracking antenna system according to claim 1 or 2, further comprising a tracking antenna control means for controlling a handover process of switching to. Each of the projectiles includes a received signal strength measuring means for measuring the received signal strength of a signal from the ground station and transmitting the signal to the ground station.
Said control station further, freedom space propagation loss between the based on the position information of the projectile, said projectile and said tracking antenna of the received signal strength and the measurement information transmitted from the ground station Is used to constantly calculate the possibility that the desired frequency bandwidth cannot be secured, and before it cannot be secured, the required frequency band is selected from the plurality of tracking antennas deployed in each of the ground stations. The tracking antenna system according to claim 1 or 2, further comprising a tracking antenna control means for controlling a handover process of switching to a tracking antenna capable of ensuring a width. The tracking antenna system according to any one of claims 1 to 4 , wherein the plurality of body antennas are a plurality of slot antennas provided in each of the plurality of predetermined areas. As the plurality of aircraft antennas, further comprising a second circumferential plurality of slot antenna provided for each of the plurality of predetermined areas around the orthogonal to the circumferential first outer shell of the projectile, according to claim 5 The tracking antenna system described in.