JPH11122690A - Underwater communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain underwater communication equipment in which full duplex 2-way communication is conducted without being affected by sound interference. SOLUTION: Communication equipment is provided with a modulator 1 that modulates transmission data DS, a transmission channel wave transmitter 3 that converts a modulation signal power-amplified by a power amplifier 2 into an ultrasonic wave and sends it in water toward other underwater communication equipment as a transmission signal SS, a reception channel wave receiver 4 that receives a transmission signal (reception signal SR) being an ultrasonic wave sent from other underwater communication equipment and a sound interference signal SK being a part of the transmission signal SS as a synthesis signal, and an adaptive filter 6 that receives an output signal of an AGC 5 as a main signal SM, applies adaptive signal processing to the signal by using the modulation signal outputted from the modulator 1 as a reference signal SH to eliminate the signal component of the sound interference signal SK from the main signal SM.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
(Unmanned Underwater Vehicle) and AUV (Autonomou
The present invention relates to an underwater communication device used for remote control of an underwater robot such as an underwater vehicle.

[0002]

2. Description of the Related Art In a conventional underwater communication device using sound waves, underwater communication is performed using sound waves having an extremely narrow frequency band of about 100 kHz as a transmission medium.

[0003]

By the way, sound waves that propagate in water have a high frequency dependence of absorption and attenuation. For this reason, when performing full-duplex two-way communication in the underwater communication device, the transmission channel should be removed in order to eliminate acoustic interference generated when the frequency bands of the two channels for transmission and reception are very close to each other. It is conceivable to attenuate the energy of the acoustic interference signal by increasing the physical distance between the transmitter for reception and the receiver for the reception channel. However, in the conventional underwater communication device, even if the distance between the transmitter for the transmission channel and the receiver for the reception channel is increased, there is a physical limit, so that the energy of the acoustic interference signal can be effectively reduced. However, there is a problem that it is difficult to attenuate it.

Further, when performing full-duplex two-way communication, it is conceivable to provide a filter having a steep frequency characteristic to remove the acoustic interference signal. However, in the conventional underwater communication device, since the frequency band of the transmission channel is very close to the frequency band of the reception channel, it is practically extremely difficult to manufacture a filter having steep frequency characteristics. There was a problem. The present invention has been made under such a background, and has as its object to provide an underwater communication device capable of performing full-duplex two-way communication without being affected by acoustic interference.

[0005]

According to a first aspect of the present invention, there is provided an underwater communication apparatus for performing underwater acoustic communication using sound waves as a transmission medium, wherein the underwater communication apparatus converts a modulated signal into a transmission signal as a sound wave to perform another underwater communication. A transmitting means for transmitting underwater toward the device, a transmitting signal as a sound wave transmitted from another underwater communication device, and an acoustic interference signal which is a part of the transmitting signal output from the transmitting means. And a filter unit for removing a component of the acoustic interference signal from an output signal of the receiving unit based on the modulated signal. The invention according to claim 2 is
2. The underwater communication device according to claim 1, wherein the filter unit performs the adaptive signal processing on an output signal of the reception unit based on the modulated signal as a reference signal and the output signal. The signal component of the acoustic interference signal is removed from the signal.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an underwater communication device according to one embodiment of the present invention. In this figure, reference numeral 1 denotes a modulator for modulating transmission data DS supplied from a control unit (not shown), and outputs a modulation result as a modulation signal. Reference numeral 2 denotes a power amplifier that power-amplifies the modulated signal.

Reference numeral 3 denotes a transmission channel transmitter for converting the modulated signal, which has been power-amplified by the power amplifier 2, into an ultrasonic wave, and transmitting the converted signal as a transmission signal SS to another underwater communication device (not shown) underwater. It is. Reference numeral 4 denotes a receiver for a receiving channel that receives a transmission signal (reception signal SR) as an ultrasonic wave transmitted from another underwater communication device and an acoustic interference signal SK which is a part of the transmission signal SS. A composite signal of the signal SR and the acoustic interference signal SK is converted into an electric signal. 5 is
This is an AGC (Automatic Gain Control) for amplifying the output signal of the reception channel receiver 4 to a certain level.

Reference numeral 6 denotes an adaptive filter having the same function as that of the adaptive noise canceller.
5 is input as the main signal SM, the modulator 1
The signal component of the acoustic interference signal SK is removed from the main signal SM by performing adaptive signal processing using the modulated signal output from the reference signal SH as a reference signal SH. A demodulator 7 demodulates an output signal of the adaptive filter 6, and outputs a demodulation result to a control unit (not shown) as reception data DR.

Next, the operation of the underwater communication device according to the above-described embodiment will be described. In FIG. 1, when transmission data DS is output from a control unit (not shown), the transmission data DS is modulated by a modulator 1 and then input to a power amplifier 2 as a modulated signal. Further, the modulated signal is input to the adaptive filter 6 as a reference signal SH. The modulated signal is power-amplified by the power amplifier 2 and then input to the transmission channel transmitter 3.

As a result, the transmission channel transmitter 3
The output signal of the power amplifier 2 is converted into a transmission signal SS as an ultrasonic wave, and transmitted to another underwater communication device (not shown). At this time, a part of the transmission signal SS becomes the acoustic interference signal SK
Is received by the transmission channel transmitter 3.

On the other hand, when a reception signal SR as an ultrasonic wave is transmitted from another underwater communication device, the reception signal SR is received by the reception channel receiver 4. At this time, the signal received by the receiving channel receiver 4 is the received signal SR.
And the above-described acoustic interference signal SK. That is, the composite signal includes a signal component of the transmission signal SS (modulated signal). The output signal of the receiving channel receiver 4 is amplified to a certain level by the AGC 5, and then input to the adaptive filter 6 as the main signal SM.

As a result, the adaptive filter 6
By performing adaptive signal processing on the main signal SM based on the reference signal SH, the acoustic interference signal SK is extracted from the main signal SM.
Is removed. As a result, the output signal of the adaptive filter 6 is a signal that does not include the signal component of the acoustic interference signal SK. Then, the demodulator 7 demodulates the output signal of the adaptive filter 6, and outputs the demodulation result to the control unit as reception data DR.

As described above, according to the underwater communication device according to the above-described embodiment, the adaptive filter 6 uses the modulated signal driving the transmission signal SS, which is the source of the acoustic interference signal SK, as the reference signal SH. Since the adaptive signal processing is performed, the signal component of the acoustic interference signal SK can be removed from the output signal of the reception channel receiver 4. Therefore, according to the underwater communication device according to the above-described embodiment, full-duplex two-way communication can be performed without being affected by acoustic interference.

[0014]

As described above, according to the present invention,
The filter means removes the component of the acoustic interference signal from the output signal of the receiving means based on the modulated signal, so that full-duplex two-way communication can be performed without being affected by acoustic interference. can get.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an underwater communication device according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 modulator 2 power amplifier 3 transmitter for transmitter channel 4 receiver for receiver channel 5 AGC 6 adaptive filter 7 demodulator DS transmission data SS transmission signal SK acoustic interference signal SR reception signal SM main signal SH reference signal DR reception data

Claims (2)

[Claims] An underwater communication device for performing acoustic communication in water using sound waves as a transmission medium, a wave transmitting means for converting a modulated signal into a transmission signal as a sound wave and transmitting the signal to another underwater communication device underwater; A transmission signal as a sound wave transmitted from another underwater communication device,
A receiving unit that receives an acoustic interference signal that is a part of the transmission signal output from the transmitting unit; and, based on the modulation signal, a component of the acoustic interference signal from an output signal of the receiving unit. An underwater communication device, comprising: a filter means for removing the underwater communication device. 2. The apparatus according to claim 1, wherein the filter unit uses the modulated signal as a reference signal and performs adaptive signal processing on an output signal of the receiving unit based on the reference signal. The underwater communication device according to claim 1, wherein the underwater communication device is removed.