JP2002330092A - Method for helicopter-satellite communication as well as helicopter-carried communication equipment used for the same and ground station communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for helicopter-satellite communication, capable of informing a transmission interruption state in a communication system for communicating between a helicopter and a ground station via the satellite as well as a relatively low cost helicopter satellite communication equipment of small size configuration and a ground station communication equipment. SOLUTION: The method for the helicopter-satellite communication comprises the steps of estimating timing of shutting off, in the transmission beam direction, with rotary blades by a shut-off timing estimating unit 15, generating a command signal for stopping transmission of a timing frame to be superposed on the shut-off timing to be input from the estimating unit 15 by a frame processing unit 17, and adding a number-of-non-transmission frames signal which describes the number of the timing frames not transmitted to the timing frame before interruption of the transmission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helicopter satellite communication method for performing communication between a helicopter and a ground station via a communication satellite, and a helicopter-mounted communication device and a ground station communication device used in the method. is there.

[0002]

2. Description of the Related Art When communication is performed between a helicopter and a ground station via a communication satellite, a signal transmitted from the helicopter is cut off by its rotor. A conventional example of a communication method before and after the interruption is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-167344. The conventional helicopter-mounted antenna device described in this publication arranges two antennas and two rotary wing detectors below the rotary wing, and avoids blocking of a transmission wave by the rotary wing by switching between the two antennas. is there. These antennas are mounted at remote locations on the helicopter, and by detecting the rotor blades by the rotor blade detector, it is determined that one antenna will cause transmission interruption by the rotor blade, and the transmission from the other antenna will be performed. Switch to. This technology enables continuous transmission from a helicopter. Japanese Patent Application Laid-Open No. 6-125287 discloses another example of a conventional communication device for mounting a helicopter. The communication device for mounting a helicopter described in this publication detects a rotor blade angle of a helicopter by a rotation angle detection device, and determines a period in which the rotor blade crosses a transmission radiation range of the antenna based on the rotation angle. One transmitting antenna is mounted on the helicopter, and transmission is stopped while the rotor wing crosses the transmission radiation range of the antenna so that the rotor does not hinder communication.

[0003]

In the conventional communication device mounted on a helicopter as described above, the communication device described in Japanese Patent Application Laid-Open No. 5-167344 is intended to realize continuous transmission by switching antennas. In addition, two antennas are required, and there is a problem that a communication device mounted on a helicopter whose spatial arrangement is limited is enlarged. Further, the communication device described in Japanese Patent Application Laid-Open No. 6-125287 stops transmission during a period in which the rotor wing crosses the transmission radiation range, and this period can be known in advance by the ground station which is the transmission destination. However, at the moment when the transmission from the helicopter is lost, the phase synchronization in the carrier wave reproduction is drawn into the error signal and becomes indefinite, and the error signal is demodulated. Also, depending on the direction in which the antenna mounted on the helicopter looks into the communication satellite, if the transmission direction from the antenna matches the rotation axis of the rotor blade or the root direction of the rotor blade as viewed from the antenna, the transmission suspension period is set. In some cases, the length of the transmission stop period becomes very short. In such a situation, the ground station determines whether the transmitted wave is in a state where it is difficult to receive the signal due to the deterioration of the communication quality such as a propagation path, a defect in the carrier wave reproducing operation, or a length of the transmission suspension period. However, there was a problem that it was not possible to make a determination. Further, in order to determine whether or not the rotor blades cross the transmission radiation range, it is necessary to mount a rotation angle detection device that detects the rotor blade angle of the helicopter. In this angle detection, high-speed angle detection processing (several milliseconds or less) is required to detect the angle of the helicopter rotor blade rotating at a high speed, and there is a problem that the angle detection device becomes expensive. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a helicopter satellite communication method capable of notifying a ground station of a transmission stop state by a rotary wing, and a relatively inexpensive and small-sized satellite communication method. It is an object of the present invention to obtain a helicopter-mounted communication device and a ground station communication device having various device configurations.

[0005]

According to a first aspect of the present invention, there is provided a helicopter satellite communication method for performing communication between a helicopter and a ground station via a communication satellite. A rotor blade detecting step for detecting at a specific rotation position; a blocking timing estimating step for estimating a blocking timing at which a transmission beam transmitted from the helicopter to the communication satellite is blocked by the rotor blade; A non-transmitted frame number transmitting step of transmitting a non-transmitted frame number signal describing the number of timing frames at which transmission is stopped, and from the helicopter to the communication satellite in a timing frame overlapping the estimated cutoff timing. Transmission stop to stop sending Steps and, the ground station having received the non-transmission frame number signal, in which a demodulation stop step of stopping the demodulation processing timing frame number of non transmission frame.

A communication device mounted on a helicopter according to a second aspect of the present invention is a communication device mounted on a helicopter and communicating with a ground station via a communication satellite. A transmission direction calculator for calculating a direction of a transmission beam to the communication satellite based on an orbital position, a transmitter for transmitting a beam in the transmission direction calculated by the transmission direction calculator, and a rotor for the helicopter When the rotor is detected by the rotor detector that detects the rotor at a specific position, the shutoff timing at which the rotor blocks the transmission beam is estimated from the relationship between the specific position of the rotor and the transmission beam direction. And a timing frame overlapping the cutoff timing estimated by the cutoff timing estimator. And a frame processing unit for generating a signal for stopping beam transmission from the transmitter in accordance with the present invention, and adding a non-transmission frame number signal describing the number of timing frames to stop transmission to the timing frame transmitted before the cutoff timing. Is provided

According to a third aspect of the present invention, there is provided a ground station communication device comprising:
A receiver for receiving a framed transmission signal transmitted from a helicopter via a communication satellite, a demodulator for demodulating a signal received by the receiver, and a deframing circuit for deframing the demodulated signal With
The demodulator stops demodulation processing for the number of frames described in the untransmitted frame number signal when the deframe circuit detects a non-transmitted frame number signal indicating that the helicopter has stopped transmitting. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A helicopter satellite communication method according to Embodiment 1 of the present invention, and a helicopter-mounted communication device and a ground station communication device used in the method will be described with reference to FIGS. FIG. 1 is a configuration diagram showing an entire device relating to a helicopter satellite communication method according to Embodiment 1, FIG. 2 is a block diagram showing a configuration of a helicopter-mounted communication device and a ground station communication device according to Embodiment 1, and FIG. 4 is a flowchart illustrating a processing flow of the helicopter-mounted communication device according to the first embodiment, FIG. 4 is a flowchart illustrating a processing flow of the ground station communication device according to the first embodiment, and FIG. 5 is a helicopter satellite communication method according to the first embodiment FIG. 2 is a schematic diagram for explaining signals communicated in FIG.

In FIG. 1, reference numeral 1 denotes a helicopter, reference numeral 2 denotes a communication satellite, and reference numeral 3 denotes a ground station. Communication is performed between the helicopter 1 and the ground station 3 via the communication satellite 2. Reference numeral 4 denotes a transmission line from the helicopter 1 to the ground station 3, and reference numeral 5 denotes a transmission line from the ground station 3 to the helicopter 1. In the helicopter 1, reference numeral 6 denotes a transmitting antenna for transmitting to the ground station 3 via the communication satellite 2, and reference numeral 7 denotes a receiving antenna for receiving a transmission signal from the ground station 3 via the communication satellite 2. Reference numeral 8 denotes a rotating blade of the helicopter 1, which cuts off the transmission line 4 by rotating the rotating blade 8.

Next, the configuration of the helicopter-mounted communication device and the ground station communication device according to the first embodiment will be described with reference to FIG. Reference numeral 9 denotes a helicopter mounted communication device mounted on the helicopter 1, and reference numeral 10 denotes a ground station communication device installed in the ground station 3. Further, the helicopter 1 is equipped with devices necessary for the navigation of the aircraft, and obtains information necessary for the helicopter-mounted communication device 9 such as attitude information from these devices. Reference numeral 11 denotes an inertial navigation device mounted on the helicopter 1. This inertial navigation device 11 is capable of
That is, it outputs information on the latitude, longitude, and altitude of the aircraft, and data on the motion of the aircraft, that is, attitude information on the roll axis, pitch axis, and azimuth axis. Reference numeral 12 denotes a rotary wing detector mounted on a helicopter. The rotary wing detector 12 detects at a specific rotation position every time the rotary wing makes one rotation around its rotation axis, and is similar to a so-called tachometer for measuring a rotation speed. Marks (marks with magnetic material pins, etc.)
Is detected by a detector provided at a specific position on the fixed side (detected by a magnetic detector or the like provided with the pin of the magnetic material on the fixed side). This rotor wing detector 12 is used as a detector for detecting the rotation speed of the rotor, which is obtained by counting the number of rotation detections in a certain period of time during normal navigation of the fuselage. Of course, the rotor detector 12
Is simple in configuration, so apart from a device for detecting the rotation speed of the rotor blades mounted for helicopter navigation, a detector capable of detecting the rotation of the rotor blades at a specific position as described above is separately provided. May be provided.

In the helicopter-equipped communication device 9 shown in FIG. 2, reference numeral 13 denotes a satellite direction calculation unit for calculating the direction of the communication satellite 2, and the position data of the airframe from the inertial navigation device 11 and the position of the communication satellite 2 in orbit. Information (latitude, longitude,
Based on the altitude information), the direction of the communication satellite 2 as viewed from the helicopter 1 is calculated. Reference numeral 14 denotes a transmitting antenna 6 in the helicopter-equipped communication device 1 based on the direction of the communication satellite 2 as viewed from the helicopter 1 calculated by the satellite direction calculation unit 13 and based on the fluctuation data of the aircraft from the inertial navigation device 11.
This is a transmission direction calculation unit that calculates the direction of the transmission beam from. The antenna is directed at the transmission beam direction calculated by the transmission direction calculation unit 14. Reference numeral 15 denotes a cutoff timing estimating unit that estimates the timing at which the rotor blades cut off the transmission beam direction calculated by the transmission direction calculation unit 14.
Reference numeral 16 denotes a time compression circuit that compresses data such as video and audio on the time axis, and 17 generates a command signal for stopping transmission of a timing frame overlapping the cutoff timing input from the cutoff timing estimating unit 15. The frame processing unit adds a non-transmission frame number signal that describes the number of non-transmission timing frames in the timing frame before the transmission stop. In the frame processing unit, a UW signal (unique word signal:
A process of adding a control signal such as a synchronization signal is also performed. Reference numeral 18 denotes a modulator that modulates a signal to be transmitted by BPSK modulation or QPSK modulation, and 19 denotes a transmitter that performs frequency conversion and high-power amplification of the signal to be transmitted. The helicopter-mounted communication device 9 also has a receiving system for receiving a transmission signal from the ground station communication device 10, a receiver 20 for low-noise amplification and frequency conversion of the received signal, and a demodulator 21 for demodulating the received signal. , A demodulated ground station communication device 1
This is a reception signal processing unit that converts a voice signal from 0 to voice and performs processing based on a control signal from the ground station communication device 10.

On the other hand, in the ground station communication device 10 shown in FIG. 2, reference numeral 23 denotes a receiving antenna for receiving a signal from the communication satellite 2, reference numeral 24 denotes a receiver for amplifying the received signal with low noise and frequency conversion, and reference numeral 25 denotes a receiver. This is a demodulator for demodulating a received signal. Reference numeral 26 denotes a deframe circuit that reads a control signal and a data signal from the received signal in synchronization with the frame of the received signal (detects and synchronizes with the UW signal). This is a time expansion circuit that performs time expansion. As described above, in the present invention, transmission and reception are performed synchronously between the helicopter-mounted communication device 9 on the transmitting side and the ground station communication device 10 on the receiving side. Further, the deframe circuit 26 performs detection processing of the untransmitted frame number signal added by the frame processing circuit 17, and when the untransmitted frame number signal is detected, the demodulator 25 instructs the demodulator 25 to stop the demodulation processing for the number of frames. Command.
The ground station communication device 10 also has a transmission system that performs transmission to a helicopter-mounted communication device, 28 is a transmission signal processing unit that generates transmission signals such as audio signals and control signals, and 29 modulates signals to be transmitted. A modulator 30 is a transmitter for performing frequency conversion and high-power amplification of the modulated transmission signal, and 31 is a transmission antenna for transmitting to the communication satellite 2. In some cases, the receiving antenna 21 and the transmitting antenna 31 may be shared, in which case the receiver 24 and the transmitter 30 are connected to the shared antenna.

Next, the flow of transmission processing in the helicopter-mounted communication device 9 will be described with reference to FIG. First, it is determined whether the rotor 8 has been detected in step S1 shown in FIG. The detection of the rotor is performed by a rotor detector 12 mounted on the helicopter 1. The rotating blade detector 12 generates a rotating blade detection signal when the rotating blade reaches a specific position during one rotation as described above. Next, in step S2, the cutoff timing at which the rotor 8 cuts off the transmission beam is estimated. When the rotor blade detection signal is generated, it is known that the rotor blade is at a specific detection position at that time. On the other hand, the direction in which the transmission beam is directed to the helicopter body (or the onboard communication device) is calculated by the satellite direction calculation unit 13 (or the transmission direction calculation unit 14). The transmission beam direction is estimated based on the rotating blade rotation speed separately output from the rotating blade detector 12 when the rotating blade at the current specific position cuts off. Since the transmit beam has a beam range, there is also a wide range of times for the rotor to cut off its transmit beam range,
The cut-off timing estimating unit 15 estimates the start and end of the cut-off of the transmission beam, and sets it as the cut-off timing.

Next, in step S3, as a process before the cutoff timing, a non-transmission frame number signal is transmitted. FIG. 5 shows a configuration of a signal to be communicated. A transmission signal from the helicopter-mounted communication device 9 transmits data such as a video signal and an audio signal in a timing frame. As shown in the upper part of FIG. 5, this timing frame includes:
A control signal and data are included. The control signal includes a UW signal (unique word signal) for synchronization, a non-transmission flag signal, and a non-transmission frame number signal. Here, the non-transmission flag signal is a signal of 0 or 1, and when the signal is 0, it means that there is no interruption by the rotor 8 of the helicopter and the next timing frame is also transmitted, and the signal is 1 In the case of, it means that the next timing frame is not transmitted because of the cutoff by the rotor 8. When the non-transmission flag signal is 1, the number of non-transmission frames is further added to the control signal. The lower signal in FIG.
FIG. 4 shows the timing of the cutoff of the transmission beam by the rotary wing, which is estimated by the cutoff timing estimating unit 15. The middle part of FIG. 5 shows a signal to be transmitted, and a timing frame filled in black represents a timing frame that is not transmitted due to cutoff by the rotor 8. In the case of FIG. 5, since the cutoff timing overlaps with two timing frames, the overlapping timing frame is not transmitted. Of course, the cutoff timing is longer or shorter depending on the positional relationship between the rotor and the transmission beam, so that the number of non-transmission timing frames changes. The number of non-transmission timing frames is called a non-transmission frame number, and is added to the control signal. In addition,
Processing relating to these frames is performed in the frame processing unit 17.

Next, in step S4, the frame processing unit 17 determines whether or not a timing frame to be not transmitted has arrived. When the timing frame to be non-transmitted arrives, the process proceeds to step S5 and the transmission process is stopped. That is, the modulator 18 stops the modulation processing, and the transmitter 19
Command to stop transmission. In response to the stop command, the modulator 18 stops the modulation process, and the transmitter 19 stops the frequency conversion and the high-power amplification. After the transmission is stopped in step S5, in step S6, the frame processing unit 17 determines whether the non-transmission timing frame has ended. If not completed, the transmission stop is continued in step S7, and if completed, the process proceeds to step S8 to restart the transmission. That is, in response to a command from the frame processing unit 17, the modulator 18 performs a modulation process on the transmitter 19.
Restarts the frequency conversion process and the high-power amplification process. Here, the command for stopping and resuming the transmission function from the frame processing unit 17 as described above may be a command for stopping and resuming the radio wave emission from the transmission antenna 6 of the helicopter-mounted communication device 9. Some of the transmission functions, such as the modulation processing in the transmitter 18 and the frequency conversion processing in the transmitter 19, may be continuously operated without depending on the stop and restart commands.

Next, the receiving process in the ground station communication device 10 will be described with reference to FIG. In a state where the rotor 8 of the helicopter 1 does not block the transmission beam of the communication device 9 mounted on the helicopter, the ground station communication device 10 performs reception and demodulation processing in step S9, and performs deframe processing to perform data such as video and audio. Reproduce. Deframing circuit 26
Detects the UW signal from the received signal and makes a determination to synchronize with the timing frame and read out the control signal and the data signal. In step S10, a non-transmission flag signal included in the control signal is monitored. When the non-transmission flag signal becomes 1, a non-transmission frame number signal is detected. When the non-transmission frame number signal is detected, the next timing frame is non-transmission, so whether or not the timing of the non-transmission timing frame has arrived is determined in step S11. When the time of the non-transmission frame comes, the process shifts to step S12 to stop the demodulation process. At this time, the deframe circuit 26 instructs the demodulator 25 to stop the demodulation processing, and the demodulator 25 stops the demodulation processing. After stopping the demodulation processing in step S12, the process proceeds to step S13, where the deframing circuit 26
Determines whether the time of the non-transmission frame has expired. If the non-transmission frame has not ended, the demodulation process is continued in step S14. If the non-transmission frame has ended, the demodulation process is restarted in step S15. The demodulation process is restarted by the demodulator 25 restarting the demodulation process in response to a command from the deframe circuit 26. Further, when the timing of the non-transmission frame arrives, by preserving the phase synchronization state of the carrier recovery and clock recovery processing in the immediately preceding demodulator 25, it is possible to prevent the phase synchronization from becoming undefined due to noise in the non-transmission state. Therefore, when demodulation is resumed after the end of the non-transmission frame, the phase synchronization of the carrier wave recovery and the clock recovery can be performed in a short time.

It should be noted that a frame in which the transmission from the helicopter 1 is not transmitted due to the cutoff of the transmission beam by the rotor 8 has been found by the deframe circuit 26. In the above description, this frame is exclusively used for demodulation processing. Although used for the stop processing, it is also possible to output the signal of the number of untransmitted frames to a user interface or the like of the ground station communication device and monitor the status of communication with the helicopter. Also,
It is also possible to arrange the non-transmission frame number signal between the helicopter-mounted communication device 9 and the ground station communication device 10 so as to be added immediately before the timing frame serving as the cutoff timing or several frames before.

[0018]

According to the first to third aspects of the present invention, the cutoff timing at which the transmission beam is cut off by the rotary wing is estimated, and a timing frame transmitted before the cutoff timing is detected. Since the number of transmission frames is transmitted, the transmission stop state can be notified to the ground station before transmission from the helicopter stops. Further, since the helicopter-mounted communication device has one transmitting antenna and the rotary wing detector mounted on the helicopter can be used, an inexpensive and small communication device can be configured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an entire helicopter satellite communication method according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a helicopter-mounted communication device and a ground station communication device according to Embodiment 1 of the present invention.

FIG. 3 is a flowchart showing a processing flow of the helicopter-mounted communication device according to Embodiment 1 of the present invention;

FIG. 4 is a flowchart showing a processing flow of the ground station communication apparatus according to Embodiment 1 of the present invention.

FIG. 5 is a schematic diagram illustrating signals communicated in the helicopter satellite communication method according to the first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Helicopter 2 Communication satellite 3 Ground station 14 Transmission direction calculation part 15 Shutdown timing estimation part 17 Frame processing part 19 Transmitter 24 Receiver 25 Demodulator 26 Deframe circuit

Continued on the front page F term (reference) 5K060 CC04 CC11 DD04 DD05 HH39 JJ23 LL04 5K061 AA01 BB10 BB12 CC25 CC45 5K072 AA24 BB13 BB22 CC02 CC13 CC15 CC34 DD02 DD13 DD16 EE35 GG02 GG12 GG13 GG15

Claims (3)

[Claims] 1. A helicopter satellite communication method for performing communication between a helicopter and a ground station via a communication satellite, a rotor wing detecting step of detecting a rotor of the helicopter at a specific rotation position, and the communication from the helicopter. In a cutoff timing estimating step of estimating a cutoff timing at which a transmission beam transmitted to a satellite is cut off by the rotor, and in a timing frame transmitted before the estimated cutoff timing, the number of timing frames for stopping transmission is described. Transmitting a non-transmitted frame number signal, transmitting a non-transmitted frame number signal, and a transmission stop step of stopping transmission from the helicopter to the communication satellite in a timing frame overlapping the estimated cutoff timing; and The received ground station is A demodulation stop step of stopping demodulation of timing frames for the number of transmission frames. 2. A helicopter-mounted communication device mounted on a helicopter and communicating with a ground station via a communication satellite. A transmission direction calculation unit that calculates the direction of the transmission beam, a transmitter that transmits a beam in the transmission direction calculated by the transmission direction calculation unit, and a rotor blade detector that detects the rotor blade of the helicopter at a specific position. A block timing estimator for estimating a block timing at which the rotary blade blocks the transmission beam from a relationship between a specific position of the rotary blade and the transmission beam direction when the rotary blade is detected; A signal for stopping beam transmission from the transmitter in a timing frame overlapping the cutoff timing estimated by the A frame processing unit configured to add a non-transmission frame number signal describing the number of timing frames to stop transmission to a timing frame to be generated and transmitted before the cutoff timing. 3. A receiver for receiving a framed transmission signal transmitted from a helicopter via a communication satellite,
A demodulator for demodulating the signal received by the receiver; and a deframe circuit for deframing the demodulated signal. The deframe circuit detects a non-transmitted frame number signal indicating that the helicopter has stopped transmitting. In this case, the demodulator stops demodulation processing for the number of frames described in the non-transmission frame number signal.