KR101743658B1 - High frequency ocean radar system - Google Patents

Abstract

A short wave marine radar system according to an embodiment of the present invention includes a first antenna unit having a monopole antenna and two loop antennas; A second antenna unit having a phase array antenna; A transmitter connected to the monopole antenna of the first antenna unit and transmitting a signal of FMCW or FMICW; A first receiving unit connected to the monopole antenna and the two loop antennas of the first antenna unit and receiving a signal of FMICW; A second receiving unit connected to the second antenna unit and receiving a signal of the FMCW; And an FMCW signal to supply the signal to the transmitter. The first receiver is selected as the receiver, and the transmitter and the first receiver are switched to transmit and receive the FMICW signal. Alternatively, the second receiver is selected as the receiver, And a control unit for controlling the transmission and reception of the data.

Description

{High frequency ocean radar system}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a short-wave marine radar system, and more particularly, to a marine radar system using a Frequency Modulation Continuous Wave (FMCW) and a Frequency Modulation Interrupted Continuous Wave (FMICW) Wave radar system.

The shortwave ocean radar system is a device for measuring sea water flow information such as flow velocity and direction. It analyzes the backscattering wave reflected by the wave of the sea surface after launching the shortwave wave from the ship or an antenna installed on the land, . These shortwave ocean radars are capable of continuously observing a wide range of sea areas simultaneously, and also have the advantage of observing the sea area on a ship or on the land for a long time without installing separate measuring sensors on the sea.

The principle that shortwave ocean radar system acquires sea water flow information is as follows.

First, we analyze the Doppler spectrum of the signal reflected from the sea surface after transmitting the signal from the antenna installed on the ground. Then, we compute the relative data measured at each station and grasp the flow rate and direction of the sea surface at each point do. At this time, the intensity of the backscattered wave reflected from the sea surface is maximized in the frequency band of the wavelength which is twice the wavelength of the sea surface wave (10 m to 100 m) by the principle of "Bragg Scattering".

Generally, a short wave ocean radar system uses a frequency modulation continuous wave (FMCW) signal capable of high power transmission to detect a wide range of sea level. In the FMCW signal shortwave marine radar system, transmission and reception are simultaneously performed by separately providing a transmission antenna and a reception antenna. Although this FMCW signaling method has a high data acquisition rate and is relatively easy to detect the direction of a signal, a sufficient separation distance between the transmitting antenna and the receiving antenna is required, and a minimum of eight array antennas There is a problem that it is difficult to apply to a case where the coastline is narrow and complicated or the military facilities are located on the coast.

In contrast to the FMCW signaling system, there is a short wave marine radar system with FMICW (Frequency Modulation Interrupted Continuous Wave) signal system which is easy to install because there is no restriction on the separation distance of the antenna. However, in the case of the FMICW method, since the transmission and reception are separated using the switching signal, the noise level of the proximity reflection signal due to the switching is high, the data acquisition rate is low, and direction detection is difficult.

On the other hand, the coastal area has relatively favorable environment for FMCW signaling like Korea's East Sea, and FMICW signaling method is comparatively advantageous like Korea's West Sea and South Sea. Accordingly, there is a need to develop a new radar system capable of changing the signaling method suited to the coastal environment.

KR 10-2014-0080718 A

In order to solve the problems of the prior art as described above, the present invention provides a method and apparatus for selectively using a Frequency Modulation Continuous Wave (FMCW) signal and an FMICW (Frequency Modulation Interrupted Continuous Wave) The aim is to provide a marine radar system.

According to an aspect of the present invention, there is provided a short wave sea surface radar comprising: (1) a first antenna unit having a monopole antenna and two loop antennas; (2) a second antenna unit having a phase array antenna; (3) a transmitting unit connected to the monopole antenna of the first antenna unit and transmitting a signal of FMCW or FMICW, (4) a receiving unit connected to the monopole antenna of the first antenna unit and the two loop antennas, (5) a second receiving unit connected to the second antenna unit and receiving a signal of the FMCW, (6) a signal of the FMCW is generated and supplied to the transmitting unit, the first receiving unit is selected as the receiving unit, And a control unit for controlling to transmit / receive a signal of the FMICW by selecting one of the first receiving units and the second receiving unit as a receiving unit.

The transmitting unit may include a transmission switch unit for turning on / off the transmission line. The first receiving unit may include a first receiving switch for turning on / off the receiving line of the first receiving unit, And the second receiving unit may include a second receiving switch unit for turning on / off the receiving line of the second receiving unit.

The control unit controls the transmission switch unit to turn on and turn off the first reception switch unit and the second switch unit or the transmission switch unit and the second reception switch unit are turned off and the first reception switch unit is turned on on so that the FMICW signal can be transmitted and received.

The control unit may control the transmission switch unit and the second reception switch unit to be turned on so that the first reception switch unit is turned off so as to transmit and receive the FMCW signal.

The transmission switch unit may include a first switch connected to the transmission line and a second switch connected to the first antenna unit more closely than the first switch in the transmission line, And a fourth switch that is closer to the first antenna unit than the third switch in the reception line.

The first input signal inputted to the first switch to control the on / off of the first switch is a first input signal to be inputted to the second switch so as to control the on / off of the second switch. 2 input signal and a different waveform.

The third input signal to be inputted to the third switch to control the on / off of the third switch is a signal input to the fourth switch to control the on / off of the fourth switch. 4 input signal.

The waveform of the first input signal may be a waveform whose rising and falling speeds are shorter than the waveform of the second input signal and the waveform of the third input signal is higher than the waveform of the fourth input signal It can be a short waveform.

The waveforms of the first input signal and the third input signal may be a spherical file, and the waveforms of the second input signal and the fourth input signal may be sinusoidal.

The second input signal and the fourth input signal may be output signals of a capacitor receiving a square wave as an input signal.

The control unit may change at least one of a frequency, a bandwidth, a chirp modulation pattern, and a chirp frequency of a transmission / reception signal according to a mode. At this time, in the case of the sea water flow information acquisition mode, the controller may change the chirp modulation pattern into a sawtooth modulation pattern. Also, in the ship movement information acquisition mode, the control unit may change the chirp modulation pattern to a triangular modulation pattern.

In the LBT (Listen Before Talk) mode, the control unit changes the frequency of the transmission / reception signal having a constant bandwidth from 23 MHz to 25 MHz at intervals of 1 Hz to 100 KHz, and determines whether or not an interference signal exists, It is possible to select the frequency of the transmission / reception signal having the smallest influence of the interference signal by selecting the frequency of the transmission / reception signal and changing the bandwidth of the selected transmission / reception signal to 1 Hz to 1 MHz.

The short wave sea surface radar according to one embodiment of the present invention includes (1) a local system including the transmitter, the first receiver, the second receiver, and the controller; (2) , A frequency of the transmitting / receiving signal, a bandwidth, a chirp modulation pattern, and a chirp frequency, and analyzes the received signal of the first receiving unit or the second receiving unit, And may include a remote computer that displays on the screen.

The short wave sea surface radar according to an embodiment of the present invention generates a reference signal for frequency conversion for the received signals of the first receiver and the second receiver as an I channel and a Q channel, And may further include an oscillation portion. A mixer for generating an FMCW signal using an oscillation frequency signal generated from an oscillator and transmitting the generated FMCW signal to a splitter and a Q channel of a local oscillator; And a splitter for branching to the I channel of the oscillation portion. Also, the first receiver and the second receiver can process the received signal in a zero-IF scheme using the signals of the I channel and the Q channel of the local oscillator.

The shortwave sea surface radar system according to an embodiment of the present invention configured as described above may be implemented by a frequency modulation continuous wave (FMCW) signal method or a Frequency Modulation Interrupted Continuous Wave (FMICW) signal (Frequency modulation continuous wave) signal method and FMICW (Frequency Modulation Interrupted Continuous Wave) signaling method at the same time.

1 shows a block diagram of a short wave marine radar system according to an embodiment of the present invention.
2 shows a detailed configuration of the transmitter 3, the first receiver 4, the controller 6, and the local oscillator 7 of the shortwave marine radar system according to the embodiment of the present invention.
3 shows a detailed configuration of the transmitter 3, the second receiver 5, the controller 6, and the local oscillator 7 of the short wave marine radar system according to the embodiment of the present invention.
4 (a) shows the first input signal and the third input signal, and Fig. 4 (b) shows the waveforms of the second input signal and the fourth input signal.
5A shows a transmission signal spectrum when only the first switch 31a is used. FIG. 5B shows a case where the first switch 31a and the second switch 31b are used together, (Yellow) when the rising and falling speeds of the waveform of the first input signal are shorter than the waveform of the second input signal and the transmission signal spectrum (yellow) when only the first switch 31a is used, (Green).

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, . In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Furthermore, terms used herein are for the purpose of illustrating embodiments and are not intended to limit the present invention. In this specification, the singular forms include plural forms as the case may be, unless the context clearly indicates otherwise. &Quot; comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements other than the stated element. Unless defined otherwise, all terms used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a shortwave marine radar system according to an embodiment of the present invention. FIG. 2 is a block diagram of a short wave marine radar system according to an embodiment of the present invention. The transmitter 3, the first receiver 4, 3 shows the detailed construction of the transmitter 3, the second receiver 5, the controller 6 and the local oscillator 7 of the short wave radar system according to the embodiment of the present invention. And shows the detailed configuration of the oscillation part 7. [

The shortwave marine radar system according to an embodiment of the present invention is a system for providing marine information by selectively using an FMCW (Frequency Modulation Continuous Wave) and an FMICW (Frequency Modulation Interrupted Continuous Wave). As shown in FIG. 1, (1), a second antenna unit (2), a transmitter (3), a first receiver (4), a second receiver (5) and a controller (6), and further includes a local oscillator 7 and a control computer 8. At this time, ocean information includes sea water flow information, ship movement information, and sea breeze movement information. Sea water flow information is information that can be provided for marine traffic, logistics, port operations, and includes sea water flow rate information, sea direction information, and the like. Ship movement information is information that can be provided for structure and control activities in case of marine disasters such as ship distress accident, oil pollution, red tide occurrence, and includes ship moving speed information and ship moving direction information. In addition, the short-wave marine radar system according to an embodiment of the present invention can provide information for tsunami detection through marine information, and can provide information necessary for cracking illegal ships and illegal fishing vessels, And provide basis information when a complaint is made.

In addition, the short wave sea surface radar system according to an embodiment of the present invention can use the FMICW to obtain the sea water flow information such as the ocean current, and use the FMCW to obtain the sea water flow information such as the ocean wave and the sea current information .

 The transmission unit 3, the first reception unit 4, the second reception unit 5, the control unit 6 and the local oscillation unit 7 may be manufactured as a PRINTED CIRCUIT BOARD (PCB) module type. In this case, since calibration is possible for each module, calibration is facilitated and each module is installed in a single housing, which makes it possible to achieve weight reduction and miniaturization, and the system can be easily moved and installed .

The first antenna unit 1 includes a monopole antenna 10 and two loop antennas 20. When the first antenna unit 1 is used for transmission, the monopole antenna 10 transmits a signal of FMCW or FMICW. When the first antenna unit 1 is used for reception, And two loop antennas 12 together receive a signal of FMICW for Direction Finding (DF). Thus, the first antenna unit 1 has an advantage that there is little restriction on the installation space.

The second antenna unit 2 includes a phase array antenna and is used only for reception unlike the first antenna unit 1 used for transmission or reception and receives a signal of FMCW .

The transmitting unit 3 is configured to transmit a signal of FMCW or FMICW and is connected to the monopole antenna 10 of the first antenna unit 1. [ The transmission unit 3 can reduce the noise by separately installing a transmission power amplifier, and can transmit a signal of a desired intensity by adjusting the transmission power.

For example, the transmission section 3 may include a transmission switch section 31, an amplifier 32, and a variable resistor 33. [

The transmission switch unit 31 performs switching for transmission of the FMICW signal. The amplifier 32 adjusts the transmission power through the variable resistor 33 and can adjust the transmission power, for example, from 1W to 100W.

In addition, the transmitter 3 may include a band pass filter (BPF) and a step attenuator 33.

At this time, the BPF is filtered using the frequency band (24 to 31 MHz) used by the transmitter 3. The Step Attenuator adjusts the transmit power, for example, to adjust the transmit power to 0 / -3 / -6 / -9 / -10 / -13 / -16 / -19 dB.

The first receiving section 4 is configured to receive the FMICW signal and is connected to the monopole antenna 11 and the two loop antennas 12 of the first antenna section 1. The first receiving unit 4 performs frequency conversion of the analog signal transmitted from the first antenna unit 1 and the reference signal transmitted from the local oscillation unit 7 into a zero-IF signal.

For example, the first receiving unit 4 includes a first receiving switch unit 41, an amplifier 42, a BPF (Band Pass Filter) 43, a splitter 44, a mixer 45, (Low Pass Filter) 46, and an OPAMP 47.

The first reception switch unit 41 performs switching for selecting the first receiving unit 4 and switching for transmission of the FMICW signal and the amplifier 42 amplifies the reception signal and the BPF 43 And performs filtering on the reception signal band (24 to 31 MHz). The splitter 44 branches the received signal to the I channel 71 and the Q channel 75 of the local oscillator 7 and the mixer 45 mixes the transmitted signal generated by the local oscillator 7 with the frequency Down Convert . The LPF 46 performs filtering on the down convert band (DC to 300 KHz), and the OPAMP 47 amplifies the down converted received signal.

The second receiving unit 5 receives the FMCW signal and is connected to the second antenna unit 2. The second receiving unit 5 performs frequency conversion of the analog signal transmitted from the second antenna unit 2 and the reference signal transmitted from the local oscillation unit 7 to zero / IF.

For example, the second receiving unit 5 includes a second receiving switch unit 51, an amplifier 52, a BPF (band pass filter) 53, a splitter 54, a mixer 55, (Low Pass Filter) 56 and an OPAMP 57.

The second reception switch unit 51 performs switching for selecting the second reception unit 5 and the amplifier 52 amplifies the reception signal and the BPF 53 is switched to the reception signal band 24 to 31 MHz Filtering is performed. The splitter 54 branches the received signal to the I channel 71 and the Q channel 75 of the local oscillator 7 and the mixer 55 mixes the transmitted signal generated by the local oscillator 7 with the frequency Down Convert . The LPF 56 performs filtering on the down convert band (DC to 300 KHz), and the OPAMP 57 amplifies the down converted received signal.

Since the first and second receiving units 4 and 5 are provided with amplifiers 42 and 52 at their input terminals and OPAMPs 47 and 57 at their output terminals, the Noise Figure can be lowered through gain adjustment, Range has the advantage to be improved. Also, the first receiving unit 4 and the second receiving unit 5 use a zero-IF scheme in which an antenna reception signal is directly converted to a baseband without intermediate frequency (IF) conversion, , There is an advantage that it is easy to modularize.

The signals received and processed by the first receiving unit 4 and the second receiving unit 5 may be input to the computer 8 via an ADC (Analog-Digital Converter). At this time, the ADC uses the reference signal generated by the oscillator 63 of the control unit 6, so that the short-wave marine radar system according to the embodiment of the present invention can improve the efficiency of the time synchronization and data processing in FFT (Fast Fourier Transform) Has an advantage of being improved.

The control unit 6 controls generation of a reference waveform, on / off control of each switch unit, and control over the system through communication with the control computer 8, that is, setting of a reference frequency and a frequency band, And adjusts the gain value of the output.

First, the control unit 6 generates a signal of the FMCW and supplies it to the transmission unit 3, and controls the selected reception unit to receive the signal by selecting one of the first reception unit 4 or the second reception unit 5 as the reception unit . At this time, either the FMCW or the FMICW is selected as the transmission / reception signal depending on whether the control unit 6 selects either the first receiving unit 4 or the second receiving unit 5 as the receiving unit. That is, in order to transmit / receive the FMICW signal, the control unit 6 selects the first receiving unit 4 as a receiving unit, and performs switchover between the transmitting unit 3 and the first receiving unit 4. At this time, when the transmission unit 3 and the first receiving unit 4 are alternately turned on / off, that is, when the transmitting unit 3 is turned on, the first receiving unit 4 is turned off the first receiving unit 4 is turned on when the transmitting unit 3 is turned off and the first receiving unit 4 is turned on when the transmitting unit 3 is turned off. For example, the control unit 6 can perform switching at a switching rate of 2048 Hz per second. In addition, when transmitting / receiving a signal of the FMCW, the control unit 6 selects the second receiving unit 5 as a receiving unit.

The transmitting unit 3, the first receiving unit 4 and the second receiving unit 5 each include a switch unit so that either the first receiving unit 4 or the second receiving unit 5 can be selected as the receiving unit, When the one receiving unit 4 is selected as the receiving unit, the switching can be further performed. At this time, in order to control the on / off operations of the switch units provided in the transmitting unit 3, the first receiving unit 4 and the second receiving unit 5, the control unit 6 controls the transmitting unit 3, And transmits the on / off control signals to the switch sections of the first receiving section 4 and the second receiving section 5, respectively.

That is, the transmission section 3 includes a transmission switch section 31 for turning on / off the transmission line, and the first reception section 4 includes a switch for turning on the reception line of the first reception section 4 The second receiving unit 5 includes a second receiving switch 5 for turning on / off the receiving line of the second receiving unit 5, (51).

At this time, when it is desired to control the transmission / reception of the FMICW signal, the control unit 6 controls the transmission switch unit 31 to be turned on and the first reception switch unit 41 and the second switch unit 51 to be off, Or the transmission switch unit 31 and the second reception switch unit 51 are turned off and the first reception switch unit 41 is turned on.

When the control unit 6 determines that the transmission switch unit 31 and the second reception switch unit 51 are turned on and the first reception switch unit 41 is turned off, ).

For example, the control unit 6 may include an MCU (Micro Controller Unit) (not shown), an oscillator 61, and a synthesizer 62.

The MCU generates a driving signal of the system and an on / off control signal of each switch unit.

The oscillator 61 generates a high-precision reference signal (for example, a 10 MHz signal), that is, an oscillation frequency signal. For example, an oven controlled crystal oscillator (OCXO) may be used as the oscillator 61.

The synthesizer 62 generates an FMCW that plays an important role in utilizing the Bragg scattering effect using the reference signal generated by the oscillator 61. [ At this time, the synthesizer 62 can perform frequency modulation (1Chirp) with a reference signal as a starting point, for example, for 1/4 second. The synthesizer 62 transmits or pre-processes the on / off control signals of the switch units generated by the MCU as they are.

Particularly, in order to minimize the loss of the received signal, the shortwave marine radar system according to the embodiment of the present invention is provided with the switch unit of the transmitting unit 3, the first receiving unit 4 and the second receiving unit 5 at the optimum position Respectively. That is, the transmission switch unit 31 includes a first switch 31a connected to the transmission line and a second switch 31b connected to the first antenna unit 1 closer to the transmission line than the first switch 31a do. The first reception switch unit 41 includes a third switch 41a connected to the reception line and a fourth switch 41b connected to the first antenna unit 1 more closely than the third switch 41a in the reception line Respectively. The second reception switch unit 51 includes a fifth switch 51a connected to the reception line and a sixth switch 51b connected to the second antenna unit 2 more closely than the fifth switch 51a in the reception line Respectively.

At this time, the first input signal inputted to the first switch 31a to control the on / off of the first switch 31a is the on / off state of the second switch 31b The second switch 31b has a waveform different from the second input signal inputted to the second switch 31b. The third input signal inputted to the third switch 41a to control the on / off of the third switch 41a is the on / off state of the fourth switch 41b. The fourth switch 41b has a waveform different from the fourth input signal input to the fourth switch 41b.

4 shows the waveforms of the first input signal, the second input signal, the third input signal, and the fourth input signal. 4 (a) shows the first input signal and the third input signal, and FIG. 4 (b) shows the waveforms of the second input signal and the fourth input signal.

Referring to FIG. 4, in the shortwave marine radar system according to an embodiment of the present invention, the waveforms of the first input signal and the waveform of the second input signal have different rising and falling rates for on / off . This is to reduce the influence of the unnecessary waves generated during the process of switching between the transmitting unit 3 and the first receiving unit 4 in order to transmit and receive the FMICW signal.

Particularly, the second switch 31b and the fourth switch 41b, which are closer to the first antenna unit 1, are connected to the first antenna unit 1 in order to protect the configuration of the transmission line and the reception line, It is preferable that it is turned on / off more slowly than the switch 31a and the third switch 41a.

That is, it is preferable that the waveform of the first input signal is a waveform having a short rising and falling speed for turning on / off the waveform of the second input signal, It is preferable that the waveform has a short rising and falling speed for turning on / off the waveform. Accordingly, the first switch 31a is turned on / off relatively earlier than the second switch 31b, and the second switch 31b is turned on relatively slowly than the first switch 31a on / off. Also, the third switch 41a is turned on / off relatively earlier than the fourth switch 41b, and the fourth switch 41b is turned on relatively slowly than the third switch 41a / Off.

5A shows a transmission signal spectrum when only the first switch 31a is used. FIG. 5B shows a case where the first switch 31a and the second switch 31b are used together, (Yellow) when the rising and falling speeds of the waveform of the first input signal are shorter than the waveform of the second input signal and the transmission signal spectrum (yellow) when only the first switch 31a is used, (Green).

That is, as shown in Figs. 5 (a) and 5 (b), when only the first switch 31a is used, a high level unnecessary emission occurs in the transmission signal. On the other hand, as shown in FIG. 5 (b), the first switch 31a and the second switch 31b are used together and the waveform of the first input signal is turned on than the waveform of the second input signal, When the rising and falling speeds are short, the unnecessary emission of the transmission signal is remarkably reduced.

4, the waveforms of the first input signal and the third input signal are preferably square waves, and the second input signal and the fourth input signal The waveform of the signal is preferably a sine wave.

The first input signal, the second input signal, the third input signal, and the fourth input signal may be an on / off control signal directly generated by the control unit 6 or an on / on / off < / RTI > control signal may be a signal preprocessed by a particular configuration while being transmitted to each switch.

For example, in the shortwave marine radar system according to the embodiment of the present invention, the controller 6 controls the first switch 31a and the third switch 41a as an on / The first switch 31a and the third switch 41a can be directly turned on / off by generating a square wave that is a waveform of the input signal and the third input signal. The shortwave marine radar system according to an embodiment of the present invention is a system in which the controller 6 generates a square wave by an on / off control signal of the second switch 31b and the fourth switch 41b A capacitor receiving the generated square wave as an input signal generates a sine wave which is an output signal of the capacitor as a second input signal and a fourth input signal to turn on / off the first switch 31a and the third switch 41a, (off) can be controlled.

The fifth input signal to be inputted to the fifth switch 51a to control the on / off of the fifth switch 51a and the fifth input signal to be inputted to the fifth switch 51a on / the sixth input signal inputted to the sixth switch 51b is an on / off control signal directly generated by the control unit 6 or an on / off signal generated by the control unit 6, ) / Off (Off) The control signal can be pre-processed for a specific configuration while it is transmitted to each switch.

The control unit 6 may change at least one of the frequency, bandwidth, chirp modulation pattern, and chirp frequency of the transmission / reception signal according to the mode. For example, the control unit 6 can select a 60 MHz measurement range and a 24 MHz frequency optimized for 2 m Hs (significant wave height) in consideration of the domestic marine environment.

In the case of the sea water flow information acquisition mode, the control unit 6 changes the chirp modulation pattern to a sawtooth modulation pattern so as to be optimized for acquiring the sea water flow information. That is, to obtain the seawater flow information, it is necessary to distinguish the 2nd order Bragg peak, and a high SNR (Signal Noise Ratio) is required to obtain the 2nd order Bragg peak. In order to increase the SNR, the first receiving unit 4 and the second receiving unit 5 of the present invention are provided with AMP, OPAMP and double switches provided at optimum positions, and the control unit 6 controls the chirp, The modulation pattern is changed to a sawtooth modulation pattern.

Further, in the ship movement information acquisition mode, the control unit 6 changes the chirp modulation pattern to a triangular modulation pattern so as to be optimized for acquiring ship movement information. In other words, it is important to obtain the back scattering of the ship rather than Bragg Scattering in order to obtain ship movement information. In order to know the moving speed of the ship, the Doppler frequency of the ship should be obtained. At this time, the controller 6 changes the chirp modulation pattern to a triangular modulation pattern so that the Doppler frequency can be easily obtained.

In the LBT (Listen Before Talk) mode, the control unit 6 changes the frequency of the transmission / reception signal having a constant bandwidth from 23 MHz to 25 MHz at intervals of 1 Hz to 100 KHz, determines the presence or absence of an interference signal, Selects the frequency of the transmitted / received signal with the least effect. Thereafter, the control unit 6 changes the bandwidth of the frequency of the selected transmission / reception signal to 1 Hz to 1 MHz, determines the existence of the interference signal, and selects the bandwidth of the frequency of the transmission / reception signal with the smallest influence of the interference signal.

The local oscillator 7 performs a function of generating a reference signal for frequency conversion of the received signal. That is, the reference signal transmitted to the first receiving unit 4 and the second receiving unit 5 is divided into an I-channel 71 and a Q-channel 75.

For example, the I-channel 71 and Q-channel 75 of the local oscillator 7 are connected to BPFs 72 and 76, splitter 73 and 77, (74, 78).

The BPFs 72 and 76 are filtered using the used frequency band of 24 to 31 MHz and the splitters 73 and 77 branch the transmission signal sources of the I channel 71 and the Q channel 75 to two ports, And the amplifiers 74 and 78 amplify the transmission signal source.

The short wave ocean radar according to an embodiment of the present invention has an advantage of improving selectivity, sensitivity, stability, and repeatability by processing a received signal in a heterodyne manner .

That is, the local oscillator 7 generates a reference signal for frequency conversion with respect to the reception signals of the first receiver 4 and the second receiver 5 by using the I channel 71 and the Q channel 75, respectively, . The controller 6 generates an FMCW signal using the oscillation frequency signal generated from the oscillator 61 and outputs the FMCW signal to the Q channel of the splitter 64 and the local oscillator 7, And a splitter 64 for splitting the received FMCW signal to the I channel 71 of the first switch 31a of the transmitter 3 and the local oscillator 7 . The first receiving unit 5 and the second receiving unit 6 process the received signal in a zero-IF manner using the signals of the I channel 71 and the Q channel 75 of the local oscillator 7. [

The computer 8 provides the user with various control modules and analysis modules. That is, the control mode provides the user with a control tool on the screen so as to control the controller 6 so that any one or more of the frequency, bandwidth, chirp modulation pattern, and chirp frequency of the transmission / reception signal can be changed . The analysis module is a module for analyzing the received signals of the first receiving unit 4 or the second receiving unit 5 according to the selection of the control module and displaying the analysis result to the user on the screen.

The computer 8 is a local computer provided together with a local system including a transmitting unit 3, a first receiving unit 4, a second receiving unit 5, a control unit 6 and a local oscillating unit 7 , Or a remote computer connected remotely via a network with the local system.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited to the embodiments described, but should be determined by the scope of the following claims and equivalents thereof.

1: first antenna unit 11: monopole antenna
12: loop antenna 2: second antenna part
3: Transmission unit 31: Transmission switch unit
31a: first switch 31b: second switch
32, 42, 52, 74, 78: amplifier 33: variable resistor
4: first receiving section 41: first receiving switch section
41a: third switch 41b: fourth switch
43, 53, 72, 76: BPF 44, 54, 73, 77: splitter
45, 55: mixer 46, 56: LPF
47, 57: OPAMP 5: second receiver
51: second receiving switch unit 51a: fifth switch
51b: sixth switch 6:
61: Oscillator 62: Synthesizer
7: Local oscillator 71: I-channel
75: Q-channel 8: Computer

Claims (10)

A first antenna unit having a monopole antenna and two loop antennas;
A second antenna unit having a phase array antenna;
And a transmission switch unit for turning on / off the transmission line through a first switch connected to the transmission line and a second switch connected to the first antenna unit closer to the first antenna unit than the first switch among the transmission line, A transmitter connected to the monopole antenna for transmitting a signal of FMCW or FMICW;
A third switch connected to the first reception line, and a first switch for turning on / off the first reception line through a fourth switch connected to the first antenna part more closely than the third switch among the first reception line, A first receiving unit including a switch unit and connected to the monopole antenna and the two loop antennas of the first antenna unit and receiving a signal of the FMICW;
A second receiving unit connected to the second antenna unit and receiving a signal of the FMCW, the second receiving switch unit turning on / off the second receiving line; And
A signal of the FMCW is supplied to the transmitter, the first receiver is selected as the receiver, the transmission is switched between the transmitter and the first receiver to control transmission / reception of the FMICW signal, or the second receiver is selected as the receiver, And a control unit for controlling the transmission /
Wherein,
The transmission switch unit is turned on and the first reception switch unit and the second switch unit are controlled to be turned off or the transmission switch unit and the second reception switch unit are turned off and the first reception switch unit is turned on Controls to transmit and receive a signal of FMICW,
The transmission switch unit and the second reception switch unit are turned on and the first reception switch unit is controlled to be turned off so as to transmit and receive the FMCW signal,
The first input signal inputted to the first switch to control the on / off of the first switch is a first input signal to be inputted to the second switch so as to control the on / off of the second switch. 2 input signal,
The third input signal to be inputted to the third switch to control the on / off of the third switch is a signal input to the fourth switch to control the on / off of the fourth switch. 4 < / RTI > input signal. delete delete The method according to claim 1,
Wherein the waveform of the first input signal is a waveform whose rising and falling speeds are shorter than the waveform of the second input signal,
Wherein the waveform of the third input signal is a waveform whose rising and falling speeds are shorter than the waveform of the fourth input signal. The method according to claim 1,
Wherein the waveforms of the first input signal and the third input signal are square waves,
And the waveform of the second input signal and the fourth input signal is a sinusoidal wave. 6. The method of claim 5,
Wherein the second input signal and the fourth input signal are output signals of a capacitor receiving a square wave as an input signal. The method according to claim 1,
Wherein,
Modulates at least one of a frequency, a bandwidth, a chirp modulation pattern, and a chirp frequency of a transmission / reception signal according to a mode,
In the case of the sea water flow information acquisition mode, the chirp modulation pattern is changed to a sawtooth modulation pattern,
And changing the chirp modulation pattern to a triangular modulation pattern when the navigation information acquisition mode is the navigation movement information acquisition mode. The method according to claim 1,
Wherein,
In the LBT (Listen Before Talk) mode, the presence or absence of an interference signal is determined while changing the frequency of a transmission / reception signal having a constant bandwidth from 23 MHz to 25 MHz at intervals of 1 Hz to 100 KHz, Select the frequency,
Wherein a bandwidth of a frequency of a transmission / reception signal having the smallest influence of an interference signal is selected by judging the existence of an interference signal while changing a bandwidth of a frequency of the selected transmission / reception signal to 1 Hz to 1 MHz. The method according to claim 1,
A local system including the transmitter, the first receiver, the second receiver, and the controller; And
And a chirp modulation pattern and a chirp frequency of the transmission / reception signal, and is capable of changing at least one of a frequency, a bandwidth, a chirp modulation pattern, and a chirp frequency of the transmission / reception signal, And a remote computer for analyzing the received signal and displaying the analysis result on a screen to a user. The method according to claim 1,
And a local oscillator for generating a reference signal for frequency conversion of the received signals of the first receiver and the second receiver, respectively, into an I channel and a Q channel,
A mixer for generating an FMCW signal using an oscillation frequency signal generated from an oscillator and transmitting the generated FMCW signal to a splitter and a Q channel of a local oscillator; And a splitter for branching to an I channel,
Wherein the first receiver and the second receiver process the received signal in a Zero-IF system using signals of the I channel and the Q channel of the local oscillator.

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