JP2000236291A - System and method for helicopter satellite communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the transmission timing of a signal according to the relative positions of a helicopter and a satellite and changes in the attitude and direction of the helicopter. SOLUTION: This satellite communicating method is implemented by a helicopter which is mounted with a directional antenna and sends and receives data through a communication path formed between the directional antenna and a satellite. The antenna angle of the directional antenna based upon the helicopter body, the attitude and direction of the helicopter body, the relative positions of the helicopter and satellite, and the rotational position of the rotor are detected respectively, a time zone GT wherein the rotor cuts off the communication path is determined from the detection results, and a transmit signal is sent out of directional antenna asynchronously according to the period Ti of the time zone GT. The transmission signal is sent out, frame by frame, and a preamble signal for synchronization is added to the header of each frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a helicopter satellite communication system and a helicopter satellite communication method in which a communication path is formed between a directional antenna mounted on a helicopter and a satellite to transmit and receive data.

[0002]

2. Description of the Related Art FIG. 5 shows a conceptual diagram of a helicopter satellite communication system. This helicopter satellite communication system relays data between a helicopter 3 (hereinafter abbreviated as a helicopter) and a user on the ground by relaying a communication satellite such as a geostationary satellite 1 or an orbiting satellite 2 having an altitude of 1000 km. It is. In such a system, helicopter 3
To transmit high-speed data such as video (for example, several Mbps or more) from a high directivity gain (for example, 30 dB).
It is necessary to provide a directional antenna having i) in the helicopter 3, and it is necessary to accurately track the directional antenna toward the communication satellite according to the movement of the helicopter, the orbit of the communication satellite, and the like.

[0003] The directional antenna as described above usually has a considerable size and mass. For example, the carrier frequency 26
In the case of an antenna with a GHz and a gain of 30 dBi, the diameter is about 30 cm and the mass is about 30 kg in parabola conversion. Such a directional antenna requiring large and precise tracking is usually provided on the roof of a helicopter 3 or the like, but such a mounting position has a problem that a communication path with a communication satellite is interrupted by a rotor (rotor blade). Is generated.

[0004] The interruption of the communication path by the rotor takes about several milliseconds, and when receiving compressed image high-speed data with little redundancy such as information compression, a burst error (random number) that cannot be repaired by an error correction function or the like. Here, it is not sporadic, but here, it refers to something like data loss for a certain period of time.), And the received data becomes useless.

As a technique for avoiding the influence of the rotor,
There is a method that employs a space diversity receiving method using a plurality of antennas. In this method, an antenna having a good reception wave is selected from a plurality of antennas by utilizing the space diversity reception function, and transmission is performed using the antenna in the good reception state.

Various techniques have been proposed in addition to the method employing the space diversity reception. The following are some examples of technologies that have been proposed so far.

For example, Japanese Patent Laid-Open No. 6-125287 discloses that a satellite communication antenna is provided below a rotor surface of a moving body, and a rotation angle of the rotor is detected to determine a period in which the rotor crosses a transmission radiation range of the antenna. The baseband signal is compressed on the time axis outside the rotor crossing period based on the discrimination result, and when the carrier signal is modulated by the compressed baseband signal, the carrier signal is turned on inside and outside the rotor crossing period based on the rotor crossing discrimination result. There has been proposed a satellite communication device that performs on / off control, frequency-converts the modulated signal, amplifies the power, and transmits the amplified signal to an antenna.

Further, Japanese Patent No. 2503883 (Japanese Patent Laid-Open No. 7-229)
No. 93) detects the periodic shielding of radio waves,
A satellite communication device has been proposed in which communication is performed within a time period excluding the timing synchronized with the shielding of the radio wave so that the influence of the shielding of the radio wave can be removed.

Further, Japanese Patent Application Laid-Open No. 7-212122 discloses that when a beam of one of at least one pair of antennas for satellite communication installed in a helicopter body is blocked by a rotor of the helicopter, the beam of the other antenna is changed. By arranging in a position not blocked by the rotor of each of the antennas, a signal having a different shielding timing by the rotor for each antenna is present independently in the transmission / reception system, and by outputting and combining a plurality of communication channel signals, Satellite communication devices have been proposed which maintain a full-duplex communication line independent of rotor motion.

Further, Japanese Patent Application Laid-Open No. 10-76999 discloses that the position of a rotor is detected, an average instantaneous interruption time with an antenna communication path is calculated from the detection result, and a plurality of instantaneous interruption times are calculated based on the average instantaneous interruption time. There has been proposed one in which antennas are switched for transmission and reception.

Furthermore, Japanese Patent Application Laid-Open No. 5-167344 discloses that when the direction of viewing a communication satellite from at least one antenna is blocked by a helicopter rotor, the direction of viewing the communication satellite from another antenna is blocked by a helicopter rotor. There has been proposed an arrangement in which the antenna is disposed at a position where the antenna is not located, the position of the rotor is detected, and the antenna is switched based on the detection result.

[0012]

The above-mentioned method employing the space diversity reception has a low transmission power,
The load on the transmission changeover switch that switches the output destination to the antenna is small (there is sufficient power durability or a device that can perform high-speed switching can be used), and the transmission speed is low. However, in the case of data transmission that requires high-power radiation and does not tolerate data errors, such as a communication satellite, the following problem arises.

When transmitting data such as images from a helicopter to a satellite, the data rate is high, and usually several tens to several hundreds of watts.
Space diversity reception system that performs hot switching, such as turning on / off the switch while the transmission output is on, because the helicopter rotor continuously interrupts the communication path many times during flight, etc. In this case, the load on the changeover switch becomes excessive due to the power durability of the switch, and the switch does not have a long time. Further, in the space diversity receiving method, switching is performed after the transmission output is cut, but such switching requires a time of about several tens of milliseconds, so that the data transmission speed is limited. For this reason, there is a problem that it is difficult to construct a system when the space diversity reception method is adopted for a communication satellite.

The technique disclosed in Japanese Patent Application Laid-Open No. 6-125287 is based on the premise of low-speed data transmission, and has a problem that it cannot be applied to high-speed data transmission of images and the like since an antenna having a low directivity gain is used. is there. In addition, there are the following problems.

The relative position between the helicopter and the satellite changes every moment in accordance with the movement and attitude of the helicopter and the orbit of the communication satellite, and the position where the rotating surface of the rotor intersects with the antenna beam changes accordingly. It is also necessary to control the timing of turning on / off the data transmission according to the change.
However, in the above-mentioned publication, the timing at which the rotor passes just above the antenna is calculated based on only the rotation angle information of the rotor to control ON / OFF of data transmission. Cannot control the transmission timing. As described above, according to the above publication, it is not possible to accurately determine the timing at which the communication path is shielded by the rotor, and thus transmission data may be lost, resulting in a decrease in communication quality.

Japanese Patent No. 2503883 (JP-A-7-22993) derives transmission timing from a helicopter by using a received wave. The signal transmission timing cannot be controlled according to the change in the relative position with respect to the satellite and the change in attitude and orientation of the helicopter.

JP-A-7-212122 and JP-A-5-1673
No. 44 describes that the influence of the shield of the rotor is avoided only by the antenna arrangement, and also in these publications, the relative position between the helicopter and the satellite and the It is not possible to control the signal transmission timing in accordance with the change in the attitude / azimuth.

The device described in Japanese Patent Application Laid-Open No. 10-76999 calculates the average instantaneous interruption time from the position of the rotor, and controls the switching of the antenna based on the average instantaneous interruption time. In the publication, too, it is impossible to control the signal transmission timing according to the change in the relative position between the helicopter and the satellite and the change in the attitude and orientation of the helicopter.

An object of the present invention is to solve the above-mentioned problem, to perform high-power radiation such as for a communication satellite, to perform data transmission without allowing a data error, and to perform communication between a helicopter and a satellite. It is an object of the present invention to provide a helicopter satellite communication system and a satellite communication method that can control signal transmission timing according to a change in a relative position and a posture / azimuth of a helicopter and have high communication quality.

[0020]

To achieve the above object, a helicopter satellite communication system according to the present invention comprises a directional antenna mounted on a helicopter and a communication path formed between the directional antenna and a satellite. In a helicopter satellite communication system in which data is transmitted and received, the helicopter has an antenna angle detecting means for detecting an antenna angle of the directional antenna with respect to an airframe, an attitude / azimuth detecting means for detecting an attitude / azimuth of the airframe, Relative position detecting means for detecting a relative position between the helicopter and the satellite; rotor rotational position detecting means for detecting a rotational position of the rotor; antenna angle detected by the antenna angle detecting means; The relative position detected by the above, the posture detected by the posture / azimuth detecting means,
Shielding timing determining means for determining the timing at which the rotor blocks the communication path based on the azimuth and the rotational position of the rotor detected by the rotor rotational position detecting means; and shielding determined by the shielding timing determining means. Signal transmission means for asynchronously transmitting a transmission signal from the directional antenna based on timing.

Further, in the helicopter satellite communication system of the present invention, a plurality of directional antennas are mounted on the helicopter, and a communication path is formed between the plurality of directional antennas and the satellite to transmit and receive data. In the communication system, the helicopter is configured to control
Attitude / azimuth detecting means for detecting the azimuth, relative position detecting means for detecting the relative position between the helicopter and the satellite, rotor rotational position detecting means for detecting the rotational position of the rotor, and the relative position detecting means Based on the detected relative position and the attitude / azimuth detected by the attitude / azimuth detecting means, the antenna directional directions of the plurality of directional antennas are controlled, and an antenna suitable for transmission is selected from among these directional antennas. Antenna directivity control means for transmitting the antenna directivity information of the selected antenna, the antenna directivity information transmitted from the antenna directivity control means, the relative position detected by the relative position detection means, and the attitude・ Position detected by azimuth detecting means
Azimuth, shielding timing determining means for determining timing at which the rotor blocks a communication path formed between the selected antenna and the satellite, based on the rotational position of the rotor detected by the rotor rotational position detecting means. Signal transmitting means for asynchronously transmitting a transmission signal from the selected antenna based on the shielding timing determined by the shielding timing determining means.

A helicopter satellite communication method according to the present invention is a satellite communication method performed in a helicopter in which a directional antenna is mounted, a communication path is formed between the directional antenna and the satellite, and data is transmitted and received. , The antenna angle of the directional antenna with respect to the aircraft, the attitude and orientation of the aircraft, the relative position between the helicopter and the satellite,
Detecting the rotational position of the rotor, respectively, based on these detection results, determine the timing at which the rotor blocks the communication path, and based on the blocking timing, asynchronously transmit a transmission signal from the directional antenna. Features.

Further, the helicopter satellite communication method according to the present invention has a plurality of directional antennas mounted thereon, a communication path is formed between the directional antennas and the satellite, and the satellite communication is performed in a helicopter in which data is transmitted and received. A method, which detects the attitude and orientation of the aircraft, the relative position between the helicopter and the satellite, based on these detection results,
Controlling the antenna directional directions of the plurality of directional antennas, selecting an antenna suitable for transmission from among the directional antennas, detecting the antenna angle of the selected antenna with respect to the body, and rotating the rotor. And based on these detection results and the detected attitude / azimuth and relative position, determine the timing at which the rotor blocks a communication path formed between the selected antenna and the satellite, and determine the blocking timing. , A transmission signal is asynchronously transmitted from the selected antenna.

(Operation) As described in the above-mentioned problem, in a helicopter in flight, the direction of the antenna changes every moment in accordance with the relative position between the helicopter and the satellite and the change in the attitude and orientation of the helicopter. Accordingly, the timing at which the rotor blocks the communication path between the antenna and the satellite also changes. For this reason, in order to accurately determine the timing at which the rotor blocks the communication path, it is necessary to detect the shielding timing according to the change in the direction of the antenna.

In the present invention as described above, the timing at which the rotor interrupts the communication path is determined based on the antenna angle, the rotational position of the rotor, the attitude and orientation of the aircraft, and the relative position between the helicopter and the satellite. The judgment is made in accordance with the change in the direction of the antenna. Therefore, in the present invention, the timing at which the transmission signal is cut off is adjusted according to the change in the direction of the antenna, and loss of the transmission data does not occur.

Further, in the present invention, the timing at which the rotor shields the communication path is detected, and the transmission signal is transmitted asynchronously based on the shielding timing, so that the transmission using the conventional space diversity reception method is performed. As described above, hot switching such as turning the switch ON / OFF while the transmission output is ON is not performed.
Therefore, according to the present invention, the burden on the transmission antenna switching mechanism and the restriction on the data transmission speed are not limited unlike the related art.

[0027]

Next, embodiments of the present invention will be described with reference to the drawings. Here, the outline of the helicopter satellite communication system is the same as that of the system of FIG. 5 described above, and therefore the description of the outline is omitted, and the configuration of the transmission / reception system of the helicopter, which is a feature of the present invention, is described in detail.

FIG. 1 shows a format of a signal transmitted from a helicopter in a helicopter satellite communication system according to an embodiment of the present invention and a transmission timing thereof. As shown in FIG. 1, in the helicopter satellite communication system of the present embodiment, the transmission timing of high-speed transmission data from the helicopter is determined in a time period during which the rotor of the helicopter blocks a transmission path with the satellite (hereinafter, referred to as “GT”). And the timing to avoid
High-speed burst (asynchronous) communication is performed between T.

Here, the period between the GTs (the period in which the communication path is interrupted by the rotor; hereinafter, this period is referred to as "Ti") differs because the number of rotors, the number of rotations, and the like vary depending on the type of helicopter. Different. More specifically, as shown in FIG. 2, when two directional antennas 6 and 7 are provided on the roof of a helicopter, for example, the steering of the directional antenna 7, that is, the relative positional relationship between the helicopter and the satellite , The positions 4 and 5 where the rotor surface intersects with the communication paths of the communication satellites 1a and 1b become faster or slower in the rotation direction of the rotor. In consideration of this, the transmission unit of the helicopter according to the present embodiment additionally has a function of detecting the rotational position (angle) of the rotor blade, a function of detecting the angle of the antenna, and a relative position between the helicopter and the satellite. And a function to detect the attitude and orientation of the aircraft, and transmit signals based on the antenna angle with respect to the aircraft, the relative position between the helicopter and the satellite, the attitude and orientation of the helicopter, the rotational position of the rotor blade, etc. It is configured such that the timing of turning off is adjusted earlier or later. This adjustment is performed by the transmission control signal Ti transmitted from the following transmission control signal generation system.
(Period between GTs).

FIG. 3 shows the main configuration of the transmission control signal generation system. The transmission control signal generation system includes a control device 11, an attitude and orientation device 12, a Ti control device 13, a position detection device 14, which are connected via a helicopter control signal bus 10, respectively.
An antenna pointing control device 15 and a rotor position detecting device 16 are provided.

The control device 11 controls each component. The attitude and orientation device 12 detects the attitude and orientation of the helicopter, the position detection device 14 detects the relative position between the helicopter and the satellite, and the rotor position detection device 16 detects the position of the rotor.

The antenna pointing control device 15 controls the directions of a plurality of directional antennas provided on the roof of the helicopter, based on the relative position of the helicopter and the satellite and the attitude and orientation of the helicopter. , An antenna suitable for transmission is selected, and antenna pointing direction information (antenna angle) of the selected antenna is transmitted onto the helicopter control signal bus 10. The timing of switching the selected antenna by the antenna pointing control device 15 is the timing of GT.

The Ti control device 13 is shielding timing determining means for determining the timing at which the rotor blocks the communication path between the directional antenna and the satellite, and determines the antenna angle transmitted on the helicopter control signal bus 10; The shielding timing is determined based on the relative position of the helicopter and the satellite, the attitude and orientation of the helicopter, and the position of the rotor, and a transmission control signal Ti (cycle between GTs) corresponding to the shielding timing is output.

When transmitting high-speed data such as images to a satellite, the transmitter of the helicopter provided with the above-mentioned transmission control signal generation system has no obstacle based on the relative position of the helicopter with the satellite and the attitude and orientation of the helicopter. Switch to the side antenna,
When the communication path is cut off by the rotor, the data transmission and the transmission output are cut off, and control is performed such that the data transmission and the transmission output are turned on at the timing when the communication path is not cut off by the rotor.

In this data transmission, the timing of securing the communication path changes due to a continuous change in the relative positional relationship between the helicopter and the satellite, a change in the attitude of the helicopter, and the like, and control is performed according to the change in the timing. On the receiving side, it is difficult to detect the timing. Therefore, the transmission signal in the communication channel securing time after the communication channel cutoff time by the rotor is for burst communication in which the header includes a signal (preamble) for synchronization. This allows the receiving side to cope with the change in the timing.

On the other hand, with respect to the receiving system of a helicopter, it is difficult to control the transmission to the helicopter side on the ground in accordance with the transmission timing from the helicopter side, because the transmission path is long and the signal delay is large. It is also difficult to perform reception on the side of the helicopter while the communication path is cut off by the rotor of the helicopter. Therefore, the receiving unit of the helicopter according to the present embodiment employs a normal space diversity receiving method, and is configured to select and receive an antenna in a good reception state among a plurality of antennas.

In the reception at the receiving unit, the incoming power,
Since the demodulation output and the like are very small, even if the switching of the antenna is controlled via the changeover switch, the power durability is not required. Therefore, even in a situation where switching is frequently performed, reliability can be ensured, and high-speed switching can be easily performed. However, when receiving high-speed and error-tolerant data, demodulate the data,
It is necessary to configure a reception / demodulation system so that antenna synchronization can be controlled by detecting frame synchronization and using frames.

Next, the specific configuration and operation of the transmission / reception system of the above-mentioned helicopter will be described in detail.

FIG. 4 is a block diagram showing the configuration of a helicopter transmitting / receiving device in the helicopter satellite communication system of the present invention. This transmission / reception device is roughly divided into transmitter 2
0, a receiver 30, a directional antenna 44a, 44b controlled by an antenna pointing control device 40, and a circulator 4 for transmitting and receiving the directional antennas 44a, 44b.
2a and 42b, and a transmission switch 41.

The transmitter 20 includes an encoder 21 and a modulation unit 2
2. It comprises a Ti control device 23, a switch 24, a mixer 25, a filter 26, an amplifier 27, and a local oscillator 28, and operates as follows.

Image data taken in by an image pickup device or the like mounted on a helicopter is input to an encoder 21, which compresses the input image data, temporarily stores it, multiplexes it with other data, and adds an error control code. And the like are incorporated into a required signal frame. The signal incorporated in the required signal frame by the encoder 21 is input to the modulation unit 22.

The signal transmission timing from the encoder 21 is controlled by the Ti control device 23, whereby the encoder 21 divides the transmission signal into frames (units).
And send it out. At this time, a preamble (signal for synchronization) is added to the beginning of the block so that resynchronization can be performed on the receiving side (see the signal format in FIG. 1).

The Ti control unit 23 controls the position, attitude and orientation of the helicopter,
Data such as the rotor rotational position (angle) is fetched, the next Ti (start time, end time) is calculated based on the data, and the frame configuration / blocking is controlled for the encoder 21 according to the calculated Ti. Output a Ti control signal 101 for performing the operation.

The signal input to the modulation section 22 is subjected to the required modulation processing similar to the modulation processing in a known transmitter. The modulated signal becomes a high frequency through a switch 24, a mixer 25 for mixing with a signal from a local oscillator 28, and a filter 26, is amplified by an amplifier 27, and is sent to a transmission switch 41.

When transmitting the transmission signals as a set (block) in frame units, the encoder 21 outputs a synchronization signal 102 synchronized with the transmission block. The synchronization signal 102 is input to the switch 24, the amplifying unit 27, and the antenna pointing control device 40 provided at the input stage of the mixer 25, thereby turning on the switch 24, the amplifying unit 27, and the antenna pointing control device 40.・ OFF control is performed.

The output of the transmitter 20 (output of the amplifier 27) is input to the directional antennas 44a and 44b via the transmission switch 41. Transmission switch 4
1 is connected to the most suitable antenna side under the control of the antenna pointing control device 40, and the switching of the antenna is performed at a timing when the transmission signal is interrupted.

The antenna pointing control device 40 fetches data such as the position, attitude and orientation of the helicopter and the satellite orbit through the helicopter signal bus 50, and controls the pointing direction of each antenna together with data such as the antenna angle status. The signals are transmitted to the drive units 43a, 43b of the directional antennas 44a, 44b.
And the synchronization signal 1 from the encoder 21
The transmission switch 41 is controlled so that the output of the transmitter 20 is input to the most appropriate one of the directional antennas 44a and 44b in synchronization with 02.

The directional antennas 44a and 44b transmit and receive radio waves to and from the geostationary satellite 1 (or the orbiting satellite 2).
Output angle status data.

The circulators 42a and 42b convert the output signal from the transmitter 20 into the directional antennas 44a and 44b.
4b, and the signals received from the directional antennas 44a and 44b are transmitted to the receiver 30. In addition, the circulators 42a and 42b also function to attenuate the large power signal from the transmitter 20 so that it does not directly enter the receiver 30.

The receiver 30 has a receiving system for each directional antenna. Here, the reception signal from the directional antenna 44a is transmitted to the amplification unit 31a, the mixer 32a, and the filter 33.
a, input to one input terminal of the changeover switch 37 via the mixer 32b and the amplifier 31c,
Is input to the other input terminal of the changeover switch 37 via the amplifier 31b, the mixer 32c, the filter 33b, the mixer 32d, and the amplifier 31d, and the comparator 36 compares the reception levels of the amplifiers 31c and 31d. By doing so, the input switch of the changeover switch 37 is controlled, and the output of the changeover switch 37 is input to the demodulation unit 27. In this receiver 30, the comparison unit 3
At 6, the reception levels of the respective reception systems are compared, and the comparison unit 36 switches the changeover switch 37 so as to demodulate the signals of the good reception systems.

The receiver 30 has a high receiving signal speed,
If no error is allowed, control is performed so that the receiving system is switched between frames of the demodulated signal and the like.

In the transmitting / receiving apparatus configured as described above, when transmitting high-speed data such as an image to the geostationary satellite 1 (or the orbiting satellite 2), the antenna on the non-failed side is controlled by the antenna pointing controller 40. The transmitter 20 is controlled so that the data transmission and the transmission output are turned off when the communication path is cut off by the rotor, and the data transmission and the transmission output are turned on at the timing when the communication path is not cut off by the rotor. When receiving the transmission data from the helicopter on the ground side via a satellite, resynchronization is performed using the preamble (signal for synchronization) added to the head of the block constituting each frame of the transmission signal. Is taken.

When a signal transmitted from the geostationary satellite 1 to the helicopter is received, the signal is received by the directional antennas 44a and 44b, and a received signal from an antenna in a good reception state is received by a normal space diversity system. Demodulated.

(Other Embodiments) When a short-distance airborne repeater such as an airplane or an airship is used instead of a satellite, the transmission power can be reduced to about several watts. In this case, in the transmitting and receiving apparatus shown in FIG. 4 described above, hot switching can be applied to the transmission changeover switch 41, and the space diversity receiving method can be adopted for the transmission system. Here, a description will be given of a configuration in which the transmitting and receiving apparatus shown in FIG.

The amplification unit 27 of the transmitter 20 is configured to switch the transmission power to a small value.
There is provided a control mode in which information 104 on an antenna in a good reception state is input from the comparison unit 34 of 0 to the antenna pointing control device 40, and the antenna pointing control device 40 switches to an antenna of a system in a good reception state. The encoder 21 is suitable for transmission switching in the control mode.
It has a function of forming a signal frame or a set (block) thereof in units of a minimum duration (for example, ms order) of the transmission switching state, and a function of making the time between frames or blocks longer than the required switching time. The inter-signal is output to the antenna pointing control device 40. The antenna pointing control device 40
(Input signal from frame or block)
, The switching timing of the transmission switch 41 is controlled.

According to the configuration in which the space diversity reception system is used in combination with the transmission system of the present embodiment, it is possible to configure a better transmission line in the helicopter by using the received signal as a monitor signal of the transmission line.

[0057]

According to the present invention configured as described above, the timing at which the transmission signal is cut off is determined by the attitude of the aircraft
By adjusting according to the change in the direction of the antenna and the direction of the antenna with the change in the relative position between the helicopter and the satellite, transmission data is not lost, so a good communication path can be secured. There is an effect that a satellite communication system having higher communication quality than the conventional one can be constructed.

In addition, selection of an antenna at the time of transmission is usually performed based on the relative position of the helicopter and the satellite and the attitude and orientation of the helicopter, and a plurality of reception systems such as space diversity reception are compared for reception. Since control to switch to a good system antenna is not performed, it is possible to simplify the operation of the transmission system to which large power is applied, reduce the load on the switching system, etc., and improve communication reliability. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a format of a transmission signal and a transmission timing thereof in a helicopter satellite communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing an intersection position between an antenna beam direction of a directional antenna and a rotor surface.

FIG. 3 is a block diagram showing a main configuration of a transmission control signal generation system of the helicopter in the helicopter satellite communication system of the present invention.

FIG. 4 is a block diagram showing a configuration of a transmitting and receiving device of the helicopter in the helicopter satellite communication system of the present invention.

FIG. 5 is a conceptual diagram schematically illustrating a helicopter satellite communication system.

[Explanation of symbols]

 Reference Signs List 1 geostationary satellite 1a, 1b communication satellite 2 orbiting satellite 3 helicopter 4,5 intersection position 6,7 directional antenna GT helicopter rotor shield time zone Ti helicopter rotor shield period

Claims (10)

[Claims] 1. A helicopter satellite communication system in which a directional antenna is mounted on a helicopter and a communication path is formed between the directional antenna and a satellite to transmit and receive data, wherein the helicopter is based on an airframe. Antenna angle detecting means for detecting the antenna angle of the directional antenna; attitude and orientation detecting means for detecting the attitude and orientation of the fuselage; relative position detecting means for detecting the relative position between the helicopter and the satellite; A rotor rotational position detecting means for detecting a rotational position; an antenna angle detected by the antenna angle detecting means; a relative position detected by the relative position detecting means; and a posture detected by the posture / azimuth detecting means. The communication path is determined based on the bearing and the rotational position of the rotor detected by the rotor rotational position detecting means; Shielding timing determining means for determining a timing at which the data is blocked, and signal transmitting means for asynchronously transmitting a transmission signal from the directional antenna based on the shielding timing determined by the shielding timing determining means. Helicopter satellite communication system. 2. A helicopter satellite communication system in which a plurality of directional antennas are mounted on a helicopter, and a communication path is formed between the plurality of directional antennas and a satellite to transmit and receive data, wherein the helicopter comprises: Attitude / azimuth detecting means for detecting the attitude / azimuth of the vehicle, relative position detecting means for detecting a relative position between the helicopter and the satellite, rotor rotational position detecting means for detecting a rotational position of the rotor, and the relative position detection Means for controlling the antenna pointing directions of the plurality of directional antennas based on the relative position detected by the means and the posture / azimuth detected by the posture / azimuth detecting means, and performing transmission from among these directional antennas. Antenna pointing control means for selecting a suitable antenna and transmitting antenna pointing direction information of the selected antenna; Antenna pointing direction information sent from the antenna pointing control means, relative position detected by the relative position detecting means, attitude / azimuth detected by the attitude / azimuth detecting means, detected by the rotor rotational position detecting means Based on the rotational position of the rotor, the shielding timing determining unit that determines a timing at which the rotor blocks a communication path formed between the selected antenna and the satellite, and the shielding timing determining unit determines Signal transmission means for asynchronously transmitting a transmission signal from the selected antenna based on shielding timing. 3. The helicopter satellite communication system according to claim 2, wherein the antenna pointing control means is configured to switch a selected antenna at a shielding timing determined by the shielding timing determining means. A helicopter satellite communication system. 4. The helicopter satellite communication system according to claim 2, wherein the helicopter receives a signal transmitted from the relay satellite using an antenna having a good reception state among the plurality of directional antennas. Receiving means for transmitting information on an antenna having a good reception state, and the antenna pointing control means further includes a control mode for selecting an antenna based on information on the antenna transmitted from the receiving means. A helicopter satellite communication system. 5. The helicopter satellite communication system according to claim 1, wherein the signal transmitting unit transmits the transmission signal in frame units and synchronizes a preamble signal for synchronizing with a header of the transmitted frame. And a helicopter satellite communication system. 6. A satellite communication method carried out in a helicopter, on which a directional antenna is mounted, a communication path is formed between the directional antenna and a satellite, and data is transmitted / received, wherein the body of the directional antenna is provided. Antenna angle with respect to
The attitude and orientation of the fuselage, the relative position between the helicopter and the satellite, and the rotational position of the rotor are each detected, and based on these detection results, the timing at which the rotor blocks the communication path is determined. Transmitting a transmission signal asynchronously from the directional antenna. 7. A satellite communication method carried out in a helicopter, on which a plurality of directional antennas are mounted, a communication path is formed between these directional antennas and a satellite, and data is transmitted / received, and Direction, the relative position between the helicopter and the satellite are detected, and based on the detection results, the antenna directing directions of the plurality of directional antennas are controlled, and an antenna suitable for transmission is selected from these directional antennas. Detecting the antenna angle of the selected antenna with respect to the fuselage and detecting the rotational position of the rotor,
Based on these detection results and the detected attitude / azimuth and relative position, determine the timing at which the rotor blocks a communication path formed between the selected antenna and the satellite, based on the blocking timing, A helicopter satellite communication method, wherein a transmission signal is asynchronously transmitted from the selected antenna. 8. The helicopter satellite communication method according to claim 7, wherein the switching timing of the selected antenna is performed based on the shielding timing. 9. The helicopter satellite communication method according to claim 7, further comprising a control mode for selecting an antenna having a good reception state from among the plurality of directional antennas as a transmission antenna. Satellite communication system. 10. The helicopter satellite communication method according to claim 6, wherein the transmission signal is transmitted in frame units, and a preamble signal for synchronizing is added to a header of the transmitted frame. A helicopter satellite communication method, characterized in that: