JP4710922B2 - Helicopter satellite communication method, and helicopter-mounted communication device and ground station communication device used in the method - Google Patents

Description

  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.

  When communication is performed between a helicopter and a ground station via a communication satellite, a signal transmitted from the helicopter side is blocked by a helicopter rotor. An example of a conventional communication method before and after the interruption is shown in Patent Document 1. In the conventional satellite communication device mounted on a helicopter described in this publication, the position of the rotor blade is estimated by detecting the angle of the rotor shaft, and the transmission wave cut-off timing by the rotor blade is obtained. Non-transmission timing information is inserted into the transmission frame from the helicopter based on the information on the cutoff timing of the transmission wave by the helicopter rotor blades, and transmitted to the ground station via the satellite. The ground station side can recognize the transmission stop state of the helicopter by detecting the non-transmission timing from the demodulated data.

JP 2002-330092 A

  According to the conventional method described in Patent Document 1, the position of the rotor blade of the helicopter is estimated by detecting the angle of the rotating shaft, and the transmission wave cutoff timing by the rotor blade is detected. Due to factors such as distance and positional relationship, there is a problem that an error occurs in the detection of the transmission wave cutoff timing by the rotor blades. In addition, transmission from the ground station communication device to the helicopter-equipped communication device is performed without recognizing the interruption timing of the rotor blades. For transmission, if the same data is not transmitted repeatedly in multiple times, the helicopter-equipped communication device cannot receive the data correctly, and the transmission bandwidth is occupied wider than the bandwidth of the data to be transmitted. It was.

  The present invention has been made to solve the above-described problems. The transmission timing of the transmission path without being interrupted by the helicopter rotor blades is estimated with high accuracy, and the transmission from the ground station to the helicopter is performed. It is an object of the present invention to obtain a helicopter satellite communication method excellent in band utilization efficiency, and a helicopter-mounted satellite communication device and ground station communication device used in the method.

The helicopter satellite communication method according to the invention of claim 1 is a helicopter satellite communication method for performing communication between a helicopter and a ground station via a communication satellite, wherein a transmission beam transmitted from the helicopter toward the communication satellite is A first transmission timing estimation step for estimating a timing at which the helicopter is interrupted by the rotor blade, and estimating a transmission timing for transmitting a transmission wave from the helicopter toward the communication satellite without being interrupted by the rotor blade; In response to a burst transmission request signal transmitted from the ground station to the helicopter, the burst frame length is not blocked by the rotor blades of the helicopter at each transmission timing from the helicopter to the communication satellite. , Preamble, data meaning the start of a burst, Beauty, transmits a burst response signal data is stored, which means the end of the burst, and receiving the burst response signal in the ground station, based on the burst frame length and reception interval of said received burst response signal A second timing for estimating a transmission timing to be transmitted from the ground station to the helicopter without being interrupted by the rotor blades of the helicopter based on the timing information and the propagation delay information in the communication propagation path based on the position of the helicopter; A transmission timing estimation step.

A helicopter-mounted communication device according to a second aspect of the present invention is a helicopter-mounted communication device that is mounted on a helicopter and communicates with a ground station via a communication satellite. The helicopter attitude information and position information, and the orbital position of the communication satellite A transmission direction calculation unit that calculates a direction of a transmission beam to the communication satellite based on the transmission direction, a transmitter that transmits a beam toward the transmission direction calculated by the transmission direction calculation unit, and the transmission by the rotor blades of the helicopter A transmission timing estimation unit that estimates a timing at which a beam is blocked and estimates a transmission timing at which a transmission wave is not blocked, and is estimated by the transmission timing estimation unit in response to a burst transmission request signal received from the ground station by the transmission timing, based on the burst frame length and reception interval of the signal, the land Station is made in an effort to estimate the transmission timing of transmitting without being cut off a communication path by the rotation vanes of the helicopter, for each of the transmission timing, has a burst frame length that is not blocked by the rotary blades of the helicopter, A burst response signal storing a preamble, data indicating the start of burst, and data indicating the end of burst is transmitted to the ground station .

According to a third aspect of the present invention, there is provided a ground station communication apparatus that receives a burst signal transmitted from a helicopter via a communication satellite, a demodulator that demodulates a signal received by the receiver, and the helicopter And a transmitter that transmits a burst transmission request signal toward the receiver, and, in response to the burst transmission request signal, is interrupted by the helicopter rotor blade that is transmitted at each transmission timing that is not interrupted by the helicopter rotor blade. Timing information based on the burst frame length and reception interval of a burst response signal having a burst frame length that is not stored, a preamble, data indicating the start of a burst, and data indicating a burst end , and the helicopter By the propagation delay information in the communication propagation path based on the position of The rotor blades of the serial helicopter is obtained with a transmission timing estimator for estimating the transmission timing to be transmitted to the helicopter without being blocked channel.

Helicopter satellite communication method according to the invention of claim 4, the first transmission timing estimation step, the rotor blades of the helicopter, in the millimeter wave band is fast transmission cycle or continuous wave than the rotation period of the rotor blade Using a radio wave, a transmission beam is transmitted from the helicopter to the communication satellite based on the detected signal by detecting the head and end of the reflected wave reflected by the rotor blade and the next reflected wave. Is estimated according to claim 1, wherein the timing at which the helicopter is cut off by the rotor blades of the helicopter is estimated.

Helicopter communication apparatus according to the invention of claim 5, the transmission timing estimator is delivered from the millimeter wave band antenna, the millimeter wave is fast transmission cycle or continuous wave than the rotation period of the rotor blades of the helicopter 3. The timing at which the transmission beam is blocked by the helicopter rotor blade is estimated by detecting the beginning and end of the reflected wave by the rotor blade of the helicopter and the next reflected wave. it is those of.

According to the first to third aspects of the invention, the burst frame length that is not blocked by the rotor blades of the helicopter at each timing that is not blocked by the rotor blades from the helicopter according to the burst transmission request signal from the ground station to the helicopter. A burst response signal in which a preamble, data indicating the start of a burst, and data indicating the end of a burst are stored is transmitted, and timing information based on a burst frame length and a reception interval of the burst response signal, And because the transmission timing from the ground station is estimated based on the propagation delay information in the communication propagation path based on the position of the above helicopter, the transmission wave from the ground station to the helicopter is not blocked by the helicopter rotor blades, and repetitive transmission is suppressed In addition, bandwidth utilization efficiency can be increased.

According to the invention described in claim 4 and claim 5, in the communication device mounted on the helicopter, the millimeter wave that is transmitted from the millimeter wave band antenna and has a transmission cycle or continuous wave faster than the rotation cycle of the rotor blade of the helicopter. Since the leading and end of the reflected wave by the rotor blade and the next reflected wave are detected and the transmission timing is estimated, the transmission timing can be estimated with high accuracy.

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 block diagram showing an overall apparatus related to a helicopter satellite communication method according to Embodiment 1 of the present invention, and FIG. 2 shows configurations of a helicopter-mounted communication apparatus and ground station communication apparatus according to Embodiment 1 of the present invention. FIG. 3 is a block diagram, FIG. 3 is a schematic diagram for explaining signals communicated in the helicopter satellite communication method according to the first embodiment of the present invention, and FIG. 4 shows a processing flow of the helicopter-mounted communication device according to the first embodiment of the present invention. FIG. 5 is a flowchart showing a processing flow of the ground station communication apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, 1 is a helicopter, 2 is a communication satellite, 3 is a ground station, and performs communication 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 transmission / reception antenna that transmits to the ground station 3 via the communication satellite 2 and receives a transmission signal from the ground station 3 via the communication satellite 2. Reference numeral 7 denotes a millimeter wave band antenna attached to the transmission / reception antenna 6 for transmitting millimeter waves to the rotating blades and receiving millimeter wave reflected waves by the rotating blades. Reference numeral 8 denotes a rotor blade of the helicopter 1, and when the rotor blade 8 rotates, the transmission lines 4 and 5 are cut off.

  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 on the ground station 3. Further, the helicopter 1 is equipped with devices necessary for navigating the aircraft, and information necessary for the helicopter-equipped communication device 9 such as attitude information is obtained from these devices. Reference numeral 11 denotes an inertial navigation device mounted on the helicopter 1. The inertial navigation apparatus 11 outputs position data of the aircraft, that is, information on the latitude, longitude, and altitude of the aircraft, and motion data of the aircraft, that is, posture information on the roll axis, pitch axis, and azimuth axis.

  In the helicopter-mounted communication device 9 of FIG. 2, reference numeral 12 denotes a satellite direction calculation unit that calculates the direction of the communication satellite 2, and the position data of the aircraft from the inertial navigation device 11 and the position information (latitude of the communication satellite 2 in orbit). , Longitude, altitude information), the direction of the communication satellite 2 viewed from the helicopter 1 is calculated. Reference numeral 13 denotes a transmission from the transmission antenna 6 in the helicopter-mounted 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 12 and the motion data of the aircraft from the inertial navigation device 11. It is a transmission direction calculation part which calculates a beam direction. The antenna is directed in the transmission beam direction calculated by the transmission direction calculation unit 13. Reference numeral 14 denotes a transmission timing estimation unit that estimates the timing at which the rotor blades block the transmission beam direction calculated by the transmission direction calculation unit 13 and estimates the transmission possible timing and the transmission frame length. 15 is a time compression circuit for compressing data such as video and audio on the time axis, and 16 is a UW signal (unique word signal) shown in FIG. 3 for each transmission frame in accordance with the transmission timing input from the transmission timing estimation unit. ) Is a frame processing unit that performs processing to add. Reference numeral 17 denotes a modulator that modulates a signal to be transmitted by BPSK modulation or QPSK modulation, and reference numeral 18 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, 19 is a receiver for low-noise amplification and frequency conversion of the received signal, and 20 is a demodulator for demodulating the received signal. 21 is a received signal processing unit that converts the demodulated audio signal from the ground station communication device 10 into sound and performs processing based on the control signal from the ground station communication device 10.

  On the other hand, in the ground station communication apparatus 10 shown in FIG. 2, 22 is a receiving antenna that receives a signal from the communication satellite 2, 23 is a receiver that performs low-noise amplification and frequency conversion on the received signal, and 24 is a received signal. It is a demodulator that demodulates. Reference numeral 25 denotes a reception signal processing unit that reads out a control signal and a data signal from the reception signal in synchronization with the frame of the reception signal. Reference numeral 26 denotes a timing at which the rotor 8 of the helicopter 1 blocks the communication propagation path from the demodulated data. A transmission timing estimation unit that estimates and determines a transmittable timing and a transmission frame length, and 27 is a time expansion circuit that extends the data read by the reception signal processing unit 25. The ground station communication device 10 also has a transmission system that performs transmission to the helicopter-equipped communication device 9, and 28 transmits transmission signals such as voice signals and control signals in accordance with the transmission timing input from the transmission timing estimation unit. A frame processing unit that performs the process of adding the UW signal shown in FIG. 3 for each frame and generates a transmission frame, 29 is a modulator that modulates the signal to be transmitted, 30 is frequency conversion and high-power amplification of the modulated transmission signal A transmitter 31 is a transmission antenna that transmits to the communication satellite 2. In some cases, the receiving antenna 22 and the transmitting antenna 31 are shared, and in this case, the receiver 23 and the transmitter 30 are connected to the shared antenna.

  Next, the configuration of signals to be communicated will be described with reference to FIG. 3, and transmission / reception operations of communication signals of the helicopter-mounted communication device 9 and the ground station communication device 10 will be described. The helicopter-mounted communication device 9 and the ground station communication device 10 perform communication by storing data such as video and audio signals in burst frames. The length of the frame shown in FIG. 3 is determined by the length of time during which communication can be performed without interrupting the communication propagation path by the rotor 8. In FIG. 3, 32 is a burst pulling preamble (PR), 33 is a unique word (UW1) meaning the beginning of the burst, 34 is a unique word (UW2) meaning continuation of the burst, and 35 is the end of burst. Is a unique word (UW3), and 36 is a data string (DATA) meaning data. Note that UW2 can be added and detected in the transmission / reception signal by placing UW2 at the DATA separation position, and processing can be performed for each united DATA. In the reception processing of the helicopter-mounted communication device 9 and the ground station communication device 10, UW1 serves as a demodulation operation start signal and UW3 serves as a demodulation operation stop signal. UW2 indicates a partition of DATA, and the received signal processing units 21 and 25 process demodulated data for each of the partitioned DATA. Therefore, since demodulation start and demodulation stop are determined by receiving a received signal, it is not necessary to perform demodulation start and stop timing determination by the received signal processing units 21 and 25, and the helicopter-mounted communication device 9 and The receiver of the ground station communication device 10 can perform demodulation processing without recognizing the frame length of the received burst frame.

Next, the flow of transmission processing in the helicopter-mounted communication device 9 will be described with reference to FIG. First, detection of the rotor blade 8 is determined in step S1. The detection of the rotor 8 is performed by the millimeter wave band antenna 7 and the transmission timing estimation unit 14 provided in the transmission / reception antenna 6 of the helicopter 1. When the rotor blade 8 crosses the direction in which the millimeter wave is transmitted from the millimeter wave band antenna 7, the millimeter wave is reflected by the rotor blade 8, and the reflected wave is received by the millimeter wave band antenna 7. The millimeter wave transmission period by the millimeter band antenna 7 is assumed to be sufficiently faster than the rotation period of the rotor blade 8 (may be a continuous wave), and the received reception signal is input to the transmission timing estimation unit 14. The transmission timing estimator 14 compares the signal level of the received signal from the millimeter wave band antenna 7 with a predetermined threshold value, and if it is greater than the threshold value, it is determined that the blade is blocked by the rotor blades. To do. Next, in step S <b> 2, the transmission timing estimation unit 14 estimates the transmission timing at which the transmission / reception beam is not blocked by the rotor blade 8, estimates the transmission timing and the transmission burst frame length, and outputs them to the frame processing unit 16. Since the timing at which the millimeter wave is reflected by the rotary blade 8 is the transmission propagation path cutoff timing, the transmission timing estimation unit 14 detects the cutoff timing from the reception signal input from the millimeter wave band antenna 7. The transmission timing can be estimated without being blocked by the rotor blades. Next, in step S3, it is determined whether transmission is possible. If it is determined in step S3 that transmission is possible, burst transmission is performed in the above-described burst frame in step S4. In step S5, it is determined whether or not to continue the next burst transmission.
Since the transmission beam has a beam range, the time required for the rotor blade to cut off the transmission beam range also has a width. In consideration of this width, the transmission timing estimation unit 14 is connected to the millimeter-wave band antenna. Based on the beginning and end of the reflected wave by the input rotor 8 and the time until the next reflected wave is input, the beginning and end of transmission of the transmission beam are estimated and set as the transmission timing. In addition, the frame processing unit 16 converts the data sequence input from the time compression circuit 15 into a transmission burst frame in accordance with the input from the transmission timing estimation unit 14, and converts UW2 for each data DATA in the transmission burst frame. UW1 is added to the head of the burst frame, and UW3 is added to the end of the burst frame.

  Next, the flow of transmission processing of the ground station communication device 10 will be described with reference to FIG. In step S6, the ground station communication device 10 continuously transmits a burst transmission request signal to the helicopter-equipped communication device 9 until the communication path is established before performing burst transmission. This burst transmission request signal may be composed of a short data string such as only PR, UW1, UW3 in FIG. In step S7, the helicopter-equipped communication device 9 responds to the ground station communication device 10 with a burst transmission request response signal at the timing when the communication propagation path is not blocked by the rotor blades and the transmission burst frame length. When the ground station communication device 10 receives the transmission request response signal from the helicopter-mounted communication device 9, the timing information that the communication propagation path is not blocked by the rotor 8 from the burst frame length of the response signal and the burst transmission interval in step S8. From the information on the current position of the helicopter 1, the position of the communication satellite 2 and the ground station 3, the propagation delay in the communication propagation path through the communication satellite 2 is calculated, and from the above-mentioned uninterrupted timing information and propagation delay information, The burst transmission timing at which the burst transmission wave transmitted from the ground station communication device 10 is not blocked by the rotor 8 is estimated by the transmission timing estimation unit 26. Next, when it is determined in step S9 that burst transmission is possible, the ground station communication device 10 performs burst transmission in step S10. In step S11, it is determined whether or not the next burst frame is to be transmitted, and if transmission is to be continued, the process returns to step S8 in which determination of the transmission possible timing is performed. As a result, it is possible to perform burst transmission without interrupting the burst frame by the rotor blade 8 of the helicopter 2. Further, the frame processing unit 28 converts the data string input from the time compression circuit 27 into a transmission burst frame in accordance with the input from the transmission timing estimation unit 26, and UW2 for each data (DATA) in the transmission burst frame. UW1 is added to the head of the burst frame, and UW3 is added to the end of the burst frame.

  As described above, the transmission timing is estimated by detecting the reflection of the millimeter wave by the rotor blade by the millimeter wave transmission / reception using the millimeter wave band antenna 7, and the transmission timing is geometrically determined by detecting the angle of the rotor blade. The transmission timing can be estimated more accurately than the estimation, and the ground station communication device 10 detects the transmission timing in the helicopter-mounted communication device 9 from the received signal and passes through the communication satellite 2. In consideration of the propagation delay of the communication signal between the helicopter 1 and the ground station 3, the transmission timing to be transmitted to the helicopter-mounted communication device 9 is estimated, whereby the ground station communication device 19 to the helicopter-mounted communication device 9 In the transmission line, transmission can be performed at a burst transmission timing that is not interrupted by the rotor blade 8. Therefore, in the transmission from the ground station communication device 9 to the helicopter-equipped communication device 10, there is no need to repeatedly transmit data in multiple times, so that the ground station communication device is repeatedly divided into multiple times on the assumption that there is a blockage. Compared with the fact that a wide transmission bandwidth several times the data bandwidth is necessary when data is transmitted from 10, the bandwidth utilization efficiency with respect to the information rate can be increased.

It is a block diagram which shows the whole apparatus regarding the helicopter satellite communication method which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the helicopter mounting communication apparatus and ground station communication apparatus which concern on Embodiment 1 of this invention. It is a schematic diagram explaining the signal communicated in the helicopter satellite communication method which concerns on Embodiment 1 of this invention. It is a flowchart which shows the processing flow of the helicopter mounting communication apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the processing flow of the ground station communication apparatus which concerns on Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Helicopter 2 Communication satellite 3 Ground station 7 Millimeter wave antenna 9 Helicopter-mounted communication device 10 Ground station communication device 14 Transmission timing estimation part (helicopter side)
16 Frame processing unit 18 Transmitter (Helicopter side)
19 Receiver (Helicopter side)
23 Receiver (ground station side)
24 Demodulator 26 Transmission timing estimator (ground station side)
30 Transmitter (ground station side)

Claims (5)

In a helicopter satellite communication method for performing communication between a helicopter and a ground station via a communication satellite, estimating a timing at which a transmission beam transmitted from the helicopter toward the communication satellite is interrupted by a rotor blade of the helicopter, A first transmission timing estimation step for estimating a transmission timing for transmitting a transmission wave from the helicopter toward the communication satellite without being interrupted by the rotor blade, and a burst transmitted from the ground station to the helicopter In response to a transmission request signal, at each transmission timing from the helicopter to the communication satellite, has a burst frame length that is not interrupted by the rotor blades of the helicopter, data indicating a preamble, a burst start, and data is stored, which means the end of the burst Transmits a paste response signal, step a, said received burst frame length and timing information based on the reception interval of the burst response signals received this burst response signal in the earth station, and a communication propagation path based on the position of the helicopter And a second transmission timing estimation step for estimating a transmission timing for transmission from the ground station to the helicopter without being interrupted by a rotor blade of the helicopter based on propagation delay information at Helicopter satellite communication method. In a helicopter-mounted communication device that is mounted on a helicopter and communicates with a ground station via a communication satellite, the direction of the transmission beam to the communication satellite is determined based on the attitude information and position information of the helicopter and the orbit position of the communication satellite. A transmission direction calculation unit to calculate, a transmitter that transmits a beam in the transmission direction calculated by the transmission direction calculation unit, and a timing at which the transmission beam is blocked by the rotor blades of the helicopter are estimated. A transmission timing estimator for estimating a transmission timing that is not blocked, and in response to a burst transmission request signal received from the ground station, a burst frame length and reception of the signal according to the transmission timing estimated by the transmission timing estimator based on the spacing, it shuts off the communication path the ground station by the rotation vanes of the helicopter Been made in an effort to estimate the transmission timing of transmitting without being, for each of the transmission timing, it has a burst frame length that is not blocked by the rotary blades of the helicopter, data indicating preamble, the start of burst, and burst A helicopter-equipped communication device, wherein a burst response signal storing data indicating the end of is transmitted to the ground station . A receiver for receiving a burst signal transmitted from a helicopter via a communication satellite; a demodulator for demodulating the signal received by the receiver; and a transmitter for transmitting a burst transmission request signal to the helicopter. In response to the burst transmission request signal, a burst frame length that is not interrupted by the helicopter rotor blades transmitted at each transmission timing that is not interrupted by the helicopter rotor blades from the helicopter , and the start of the preamble and burst And the timing information based on the burst frame length and reception interval of the burst response signal in which the data indicating the end of the burst is stored , and the propagation delay information on the communication propagation path based on the position of the helicopter The communication path is connected by the rotor blades of the helicopter. Further comprising a transmission timing estimator for estimating the transmission timing to be transmitted to the helicopter without being cross ground station communication apparatus according to claim. In the first transmission timing estimation step, the rotor blade of the helicopter is reflected by the rotor blade using a millimeter wave band radio wave having a transmission cycle or continuous wave faster than the rotation cycle of the rotor blade. The start and end of the reflected wave and the next reflected wave are detected, and based on the detected signal, the timing at which the transmission beam transmitted from the helicopter to the communication satellite is interrupted by the rotor blade of the helicopter is estimated. The helicopter satellite communication method according to claim 1, wherein: The transmission timing estimation unit is transmitted from a millimeter wave band antenna, the transmission period is faster than the rotation period of the rotor blades of the helicopter or a continuous wave of the reflected wave by the rotor blades of the helicopter of the millimeter wave and The helicopter-mounted communication device according to claim 2, wherein a timing at which the transmission beam is interrupted by a rotor blade of the helicopter is estimated by detecting a next reflected wave .

Images