JP6339074B2 - Sea state detection device, radar device, sea state detection method, and program - Google Patents

Description

  The present invention relates to a sea state detection device, a radar device, a sea state detection method, and a program.

  For example, a ship sails on the sea. A ship acquires sea state information around the ship using various sensors as information necessary for navigation. Examples of such a sensor include a sensor for measuring waves and a sensor for measuring tidal currents. In order to detect these sea conditions, a radar apparatus may be used (for example, refer patent document 1). The apparatus described in Patent Document 1 acquires a sea surface clutter signal by radar detection using microwaves. The microwave is generated using, for example, a magnetron, and transmitted from a ship antenna to the sea area.

Japanese Patent Laying-Open No. 2003-21680 ([0001])

  The microwave generated by the magnetron is reflected by, for example, the sea surface and received by the radar device as a sea clutter signal. In this case, the sea clutter signal has amplitude information. The radar apparatus generates image data having echo level (amplitude value) data corresponding to the amplitude. This amplitude value is set in the sea area around the ship equipped with the radar device.

  Waves are detected based on the luminance distribution in the image specified by the image data.

  Here, the attenuation rate of the amplitude value of the sea clutter signal increases as the position where the microwave is reflected and the sea clutter signal is farther from the ship position, that is, as the distance over which the sea clutter signal flies is longer. That is, the amplitude value is affected by the distance. Therefore, it is necessary to suppress such attenuation of the amplitude value. In other words, it is necessary to correct the trend component due to distance attenuation.

  The trend component is corrected by correcting the amplitude value of the sea clutter signal using the approximate curve corresponding to the distance attenuation. However, this approximate curve must be set with high accuracy in consideration of the attenuation characteristics of the sea clutter signal. For this reason, it is difficult to accurately correct the distance attenuation in the radar apparatus, and in some cases, the amplitude value of necessary data may be excessively reduced.

  The present invention provides a sea state detection device, a radar device, a sea state detection method, and a program capable of more easily detecting accurate sea state information around a ship or the like in view of the above situation. With the goal.

(1) In order to solve the above problems, a sea state detection device according to an aspect of the present invention includes an image data generation unit and a sea state data generation unit. The image data generation unit is configured to generate, as image data, a Doppler velocity distribution for a predetermined sea state based on a reception signal including amplitude information and phase information obtained using a predetermined transmission signal. ing. The sea state data generation unit is configured to generate sea state data that identifies the sea state based on the image data. In addition, the sea state data generation unit is configured to generate the sea state data by performing image analysis on a change in the Doppler velocity specified by the plurality of image data having different observed times. The transmission signal is a microwave signal transmitted from an antenna installed at one place, and the wavelength of the microwave signal is shorter than the wavelength of the ultrashort wave.

(2) good Mashiku, the received signal is obtained using the transmission signal generated by the solidified radar device.

( 3 ) Preferably, the sea state data generation unit generates data specifying at least one of a sea surface tidal current and a wave as the sea state data.

( 4 ) In order to solve the above-described problems, a radar apparatus according to an aspect of the present invention includes the sea state detection apparatus and an antenna unit. The antenna unit is configured to be capable of rotating about an axis extending vertically, and transmits and receives the received signal and the received signal.

( 5 ) In order to solve the above problems, a sea state detection method according to an aspect of the present invention includes an image data generation step and a sea state data generation step. In the image data generation step, a Doppler velocity distribution for a predetermined sea state is generated as image data based on a received signal including amplitude information and phase information obtained using a predetermined transmission signal. The sea state data generation step generates sea state data for specifying the sea state based on the image data. In the sea state data generation step, the sea state data is generated by performing image analysis on the change in the Doppler velocity specified by the plurality of image data having different observed times. The transmission signal is a microwave signal transmitted from an antenna installed at one place, and the wavelength of the microwave signal is shorter than the wavelength of the ultrashort wave.

( 6 ) In order to solve the above problem, a program according to an aspect of the present invention causes a computer to execute an image data generation step and a sea state data generation step. In the image data generation step, a Doppler velocity distribution for a predetermined sea state is generated as image data based on a received signal including amplitude information and phase information obtained using a predetermined transmission signal. The sea state data generation step generates sea state data for specifying the sea state based on the image data. In the sea state data generation step, the sea state data is generated by performing image analysis on the change in the Doppler velocity specified by the plurality of image data having different observed times. The transmission signal is a microwave signal transmitted from an antenna installed at one place, and the wavelength of the microwave signal is shorter than the wavelength of the ultrashort wave.

  According to the present invention, it is possible to more easily detect accurate information on sea conditions around a ship or the like.

It is a mimetic diagram showing the state where a ship provided with a radar device concerning one embodiment of the present invention is navigating the sea. It is a block diagram which shows schematic structure of a radar apparatus. It is a schematic diagram which shows an example of the image specified by scan data. It is a schematic diagram for demonstrating the processing result of a Doppler speed map production | generation part. It is a flowchart for demonstrating an example of the flow of a process in the sea state detection apparatus of a radar apparatus.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention can be widely applied as a sea state detection device, a radar device, a sea state detection method, and a program.

  FIG. 1 is a schematic diagram showing a state where a ship equipped with a radar device 1 according to an embodiment of the present invention is navigating on the sea. In FIG. 1, the inside of the circular region shows the ship and the periphery of the ship. FIG. 2 is a block diagram illustrating a schematic configuration of the radar apparatus 1.

  With reference to FIG. 1, in this embodiment, a ship provided with a radar device 1 is referred to as own ship 50. FIG. 1 shows a state in which the own ship 50 is navigating toward the destination 52 of the land 51, and shows a state in which a wave 53 and a surface tide 54 are generated around the own ship 50. Yes.

  A wave crest line 531 of the wave 53 is a wave head that exists substantially continuously in an elongated streak shape or a water bubble generated thereby. The crest line 531 of the wave 53 advances from the bow side of the own ship 50 toward the stern side (south), for example. The surface tide 54 is directed from the starboard side of the ship 50 toward the port side (west), for example. The own ship 50 is a large ship such as a tanker, and sails toward the destination 52 on the land 51.

  The radar apparatus 1 is provided to acquire information necessary for navigation of the ship 50 by transmitting and receiving microwaves (electromagnetic waves). The radar apparatus 1 is provided in the own ship 50.

  With reference to FIG. 1 and FIG. 2, the radar device 1 is a solidified radar device, and includes an antenna device 2, a sea state detection device 3, and a display device 4.

  The antenna device 2 includes a transmission unit 5, an antenna unit 6, a reception unit 7, and an A / D conversion unit 8.

  The transmission unit 5 is configured to generate a transmission signal (detection signal) S1 using a solid element (semiconductor element). The transmission unit 5 outputs the transmission signal S1 to the antenna unit 6 at every predetermined period.

  The antenna unit 6 is a radar antenna that can transmit the transmission signal S1 as a pulsed radio wave having strong directivity. The antenna unit 6 is configured to receive a reception signal S2 including an echo signal (reflected wave) from a target or the like. The antenna unit 6 is, for example, a slot array antenna, and rotates about an axis that extends vertically through the ship 50 (azimuth direction C1). The rotation speed of the antenna unit 6 is constant.

  Note that the radar apparatus 1 measures the time until the reception signal S2 generated by transmitting the transmission signal S1 is received. Thereby, the radar apparatus 1 can detect the distance r from the ship 50 to the target.

  The antenna unit 6 is configured to be able to rotate 360 ° on a horizontal plane, and rotates (spins) in an azimuth direction C1 around a vertical axis extending vertically. The antenna unit 6 is configured to repeatedly transmit and receive the signals S1 and S2 while changing the transmission direction of the transmission signal S1 (changing the rotation angle of the antenna unit 6). With the above configuration, the radar apparatus 1 can detect a range of several nautical miles around the ship 50 over 360 °.

  In the present embodiment, an operation from transmission of the transmission signal S1 (pulsed radio wave) to transmission of the next transmission signal S1 is referred to as “sweep”. Further, the operation of rotating the antenna unit 6 by 360 ° while transmitting / receiving radio waves is referred to as “scan”.

  The receiving unit 7 detects and amplifies the received signal S2 received by the antenna unit 6. The reception signal S2 includes an echo signal and a noise signal. The echo signal is a reflected wave on the target and the sea surface with respect to the transmission signal S <b> 1 among the signals received by the antenna unit 6. The receiving unit 7 outputs the received signal S2 to the A / D conversion unit 8.

  The A / D converter 8 samples the analog reception signal S2 and converts it into digital data (echo data D1) composed of a plurality of bits. Here, the echo data D1 is IQ signal data. In the present embodiment, the echo data D1 includes data for specifying the echo level (amplitude value) of the echo signal received by the antenna unit 6. The echo data D1 includes data for specifying the phase of the echo signal. The A / D converter 8 outputs the echo data D1 to the sea state detection device 3.

  The sea state detection device 3 is configured to detect sea state around the ship 50. In the present embodiment, the sea state detection device 3 detects a wave 53 around the ship 50 and a surface tide 54 around the ship 50 as a sea state. The sea state detection device 3 is formed using a CPU, a RAM, a ROM, and the like.

  The sea state detection device 3 includes a scan data storage unit 11, a Doppler velocity map generation unit 12, and a sea state data generation unit 13.

  The scan data storage unit 11 is configured to generate the scan data D2 by storing the echo data D1 output from the A / D conversion unit 8. The scan data storage unit 11 sets an r-θ coordinate system centered on the ship 50. r is a variable indicating the straight line distance from the ship 50. θ is, for example, an angle of the azimuth direction C1 in which the direction facing the bow of the own ship 50 is θ = zero.

  The scan data accumulation unit 11 accumulates echo data D1 obtained by a plurality of sweeps for one scan, thereby generating scan data D2 including amplitude information and phase information. The scan data D2 includes data indicating amplitude values at various points in the r-θ coordinate system. An example of the image P1 specified by the scan data D2 is shown in FIG.

  FIG. 3 is a schematic diagram illustrating an example of the image P1 specified by the scan data D2. Referring to FIGS. 1 to 3, in image P <b> 1, a streak region R <b> 53 having an amplitude value equal to or greater than a predetermined threshold value (noise level) is formed in a region corresponding to wave crest line 531. In the image P1, a wavefront region R54 caused by sea surface reflection (sea clutter) is formed. The amplitude value of the region R54 is not less than the predetermined threshold value (noise level).

  The scan data storage unit 11 generates scan data D2 for each echo data D1 obtained in one scan. As a result, the scan data storage unit 11 generates scan data D2 for each scan.

  FIG. 3 shows an image P1 based on scan data D2 at a certain n scan time point (n is a natural number). FIG. 3 also shows an image P2 based on the scan data D2 at the (n + 1) scan time. The image P2 is different from the image P1 in that the positions of the regions R53 ′ and R54 ′ in the image P2 are different from the corresponding regions R53 and R54 in the image P1.

  With the above configuration, the scan data storage unit 11 generates scan data D2 based on the received signal S2 obtained by detecting the surroundings of the ship 50 using the transmission signal S1 (detection signal). The scan data accumulation unit 11 outputs the generated scan data D2 to the Doppler velocity map generation unit 12.

  FIG. 4 is a schematic diagram for explaining the processing result of the Doppler velocity map generation unit 12. 1 to 4, the Doppler velocity map generation unit 12 is an example of the “image data generation unit” in the present invention. The Doppler velocity map generator 12 is configured to calculate the distribution of the Doppler velocity vector DV of each sea state in the sea area around the ship 50 based on the scan data D2 (received signal S2). The Doppler velocity map generation unit 12 generates Doppler velocity map data D3 that specifies the distribution of the Doppler velocity vector DV.

  More specifically, the Doppler velocity map generation unit 12 calculates the Doppler velocity vector DV (DV53, DV54) for the sea state (the wave 53 and the surface current 54) based on the received signal S2 including the amplitude information and the phase information. calculate. Then, the Doppler speed map generation unit 12 generates Doppler speed map data D3 that specifies the distribution of the Doppler speed vectors DV53 and DV54. The Doppler velocity map data D3 is an example of the “image data” in the present invention.

  In FIG. 4, the Doppler velocity vector DV (DV53, DV54) is indicated by a circle and an arrow, but this need not be the case. For example, in the Doppler velocity vectors DV53 and DV54, the direction may be indicated by color and the velocity value may be indicated by luminance.

  In the present embodiment, the Doppler velocity map generation unit 12 calculates the Doppler velocity vector DV53 of the wave 53 and the Doppler velocity vector DV54 of the surface current 54 using the scan data D2.

  As described above, the antenna device 2 is a solid-state radar device, and the reception signal S2 has phase information in addition to amplitude information of the reception signal S2. Therefore, the Doppler speed map generation unit 12 can detect the Doppler speed vectors DV53 and DV54 along the distance direction B1 (radial direction) from the ship 50.

  In the present embodiment, the Doppler velocity map generation unit 12 calculates a Doppler velocity vector DV (DV53, DV54) by performing FFT processing or pulse pair processing.

  The Doppler velocity vector DV53 is a Doppler velocity vector of the wave 53 at a position where the wave 53 is generated. Similarly, the Doppler velocity vector DV54 is a Doppler velocity vector of the surface layer flow 54 at a position where the surface layer flow 54 is generated.

  The directions of the Doppler velocity vectors DV53 and DV54 are calculated based on a change in the frequency of the reception signal S2 with respect to the transmission signal S1.

  The Doppler speed map generation unit 12 generates Doppler speed map data D3 including data specifying the Doppler speed vectors DV53 and DV54. The Doppler velocity map generator 12 outputs the Doppler velocity map data D3 to a wave data generator 131 and a surface current data generator 132, which will be described later, of the sea state data generator 13.

  The sea state data generation unit 13 is configured to generate sea state data that identifies a predetermined sea state (the wave 53 and the surface current 54) around the ship 50 based on the Doppler velocity map data D3. The “around the own ship 50” refers to a sea area directly related to the navigation of the own ship 50, for example, an area from the own ship 50 to about 8 nautical miles. In this embodiment, the oceanographic data generation unit 13 is configured to generate wave data D4 that specifies the velocity vector of the wave 53 and the like, and surface current data D5 that specifies the velocity vector of the surface current 54 and the like. .

  The sea state data generation unit 13 includes a wave data generation unit 131 and a surface tidal current data generation unit 132.

  The wave data generation unit 131 is configured to generate wave data D4 as data specifying the waves 53 around the ship 50. The wave data generation unit 131 reads the Doppler velocity map data D3. The wave data generation unit 131 detects the movement of the wave 53 (the height, period, direction, and the like of the wave 53) by wave analysis that performs FFT processing on the Doppler velocity map data D3. The wave data generation unit 131 generates wave data D4 by the above processing. The wave data generation unit 131 outputs the wave data D4 to the display device 4.

  The surface tide data generator 132 is configured to detect the surface tide 54 in the sea around the ship 50. In the present embodiment, the surface tide refers to, for example, a tide having a depth of about 10 m from the sea surface.

  The surface current data generation unit 132 refers to, for example, the multiple Doppler velocity map data D3 at different scan points. Next, the surface current data generation unit 132 detects the surface current 54 by performing image analysis (performing optical flow processing) on the change in speed specified by the Doppler speed map data D3.

  For example, the surface tidal current data generation unit 132 detects a change corresponding to a position change between the region R54 in the image P1 and the region R54 ′ in the image P2 from the Doppler velocity map data D3 at a plurality of scan points. As a result, the surface current data generation unit 132 detects the surface current 54 around the ship 50.

  The surface current data generator 132 generates surface current data D5 that identifies the detected surface current 54. The surface layer current data generation unit 132 outputs the surface layer current data D5 to the display device 4.

  The display device 4 is, for example, a plotter, and is configured to perform display based on the wave data D4 and display based on the surface layer power flow data D5. More specifically, the display device 4 displays information on the waves 53 around the ship 50 based on the wave data D4. In addition, the display device 4 displays information on the surface tide 54 around the ship 50 based on the surface tide data D5. Thereby, the operator of the radar apparatus 1 can know the state of the waves 53 around the ship 50 and the state of the surface tidal current 54.

  FIG. 5 is a flowchart for explaining an example of the processing flow in the sea state detection device 3 of the radar device 1. In addition, below, when explaining the flow of the process in the sea state detection apparatus 3, figures other than FIG. 5 are also referred suitably.

  The sea state detection device 3 reads out and executes each step of the flowchart shown below from a memory (not shown). This program can be installed externally. The installed program is distributed in a state stored in a recording medium, for example.

  In the sea state detection device 3, first, the scan data storage unit 11 generates scan data D2 using the echo data D1 given from the A / D conversion unit 8 (step S1). Next, the Doppler velocity map generation unit 12 generates Doppler velocity map data D3 using the scan data D2 (step S2).

  Next, the sea state data generation unit 13 generates sea state data (step S3). Specifically, the wave data generation unit 131 generates wave data D4 using the Doppler velocity map data D3. Further, the surface layer power flow data generation unit 132 generates the surface layer power flow data D5 using the Doppler velocity map data D3. The sea state data generation unit 13 outputs the wave data D4 and the surface current data D5 to the display device 4 (step S4).

[Program] The program related to the sea state detection device 3 of the radar apparatus 1 of the present embodiment may be a program that causes a computer to execute the process of the sea state detection device 3. By installing and executing this program on a computer, the sea state detection device 3 and the sea state detection method in the present embodiment can be realized. In this case, the CPU (Central Processing Unit) of the computer functions as a scan data storage unit 11, a Doppler velocity map generation unit 12, and a sea state data generation unit 13 (wave data generation unit 131, surface current data generation unit 132), Process. The sea state detection device 3 may be realized by cooperation of software and hardware as in the present embodiment, or may be realized by hardware.

  As described above, according to the sea state detection device 3 according to the present embodiment, the Doppler velocity map generator 12 generates Doppler velocity map data D3 as image data based on the received signal S2 including amplitude information and phase information. Generate. The sea state data generation unit 13 then generates sea state data (wave data D4 and surface current data D5) based on the Doppler velocity map data D3. According to such a configuration, the sea state data generation unit 13 generates sea state data (wave data D4 and surface current data D5) based on the Doppler velocity vector DV, not the amplitude value specified by the scan data D2. Can do. That is, the sea state data generation unit 13 does not depend on the amplitude value of the reception signal S2 that attenuates according to the distance from the ship 50, but based on the phase information of the reception signal S2 that does not depend on the distance from the ship 50. Data (wave data D4 and surface current data D5) can be generated. For this reason, the sea state detection device 3 does not perform delicate correction setting (trend attenuation correction) of the scan data D2 in consideration of the attenuation characteristic of the amplitude value of the reception signal S2 according to the distance from the ship 50. Sea state data (wave data D4 and surface current data D5) can be generated. For this reason, according to the sea state detection apparatus 3, the accurate information of the sea state around the ship 50 can be detected more easily.

  Further, according to the sea state detection device 3, the reception signal S2 is obtained by using the transmission signal S1 generated by the antenna device 2 as the solidification radar device. With such a configuration, the reception signal S2 has phase information in addition to amplitude information. As a result, the Doppler velocity vector data generation unit 13 can calculate the Doppler velocity vector DV.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment. The present invention can be variously modified as long as it is described in the claims. For example, the following modifications may be made.

  (1) In the above-described embodiment, a description has been given of an example in which waves and surface tides are detected as detection target sea conditions around the ship. However, this need not be the case. Other sea conditions such as wind may be detected as sea conditions to be detected around the ship. Further, only one of waves and surface currents may be detected.

  (2) Moreover, although this invention is a sea state detection apparatus, it can be used also as a detection apparatus in fresh water.

  The present invention can be widely applied as a sea state detection device, a radar device, a sea state detection method, and a program.

DESCRIPTION OF SYMBOLS 1 Radar apparatus 3 Sea state detection apparatus 6 Antenna part 12 Doppler velocity map generation part (image data generation part)
13 Sea state data generator D3 Doppler velocity map data (image data)
D4 Wave data (sea state data)
D5 Surface tidal current data (sea state data)
DV Doppler velocity vector (Doppler velocity)
S1 transmission signal S2 reception signal

Claims (6)

An image data generation unit that generates, as image data, a Doppler velocity distribution for a predetermined sea state based on a reception signal including amplitude information and phase information obtained using a predetermined transmission signal;
A sea state data generation unit that generates sea state data that identifies the sea state based on the image data;
With
The sea state data generation unit generates the sea state data by performing image analysis on the change in the Doppler velocity specified by the plurality of image data having different observed times .
The transmission signal is a microwave signal transmitted from an antenna installed at one place,
The sea state detection device characterized in that the wavelength of the microwave signal is shorter than the wavelength of the ultrashort wave . The sea state detection device according to claim 1 ,
The sea state detection device, wherein the reception signal is obtained by using the transmission signal generated by a solid-state radar device. The sea state detection device according to claim 1 or 2 ,
The sea state data generation unit generates data that specifies at least one of a sea surface tidal current and wave data as the sea state data. A sea state detection device according to any one of claims 1 to 3 ,
An antenna unit configured to be capable of rotating about an axis extending vertically, and for transmitting and receiving the transmission signal and the reception signal;
A radar apparatus comprising: An image data generation step for generating, as image data, a Doppler velocity distribution for a predetermined sea state based on a reception signal including amplitude information and phase information obtained using a predetermined transmission signal;
Generating sea state data for identifying the sea state based on the image data;
Including
The sea state data generation step generates the sea state data by performing image analysis on the change in the Doppler velocity specified by the plurality of image data having different observed times .
The transmission signal is a microwave signal transmitted from an antenna installed at one place,
A sea state detection method, wherein a wavelength of the microwave signal is shorter than a wavelength of an ultrashort wave . On the computer,
An image data generation step for generating, as image data, a Doppler velocity distribution for a predetermined sea state based on a reception signal including amplitude information and phase information obtained using a predetermined transmission signal;
Generating sea state data for identifying the sea state based on the image data;
And execute
The sea state data generation step generates the sea state data by performing image analysis on the change in the Doppler velocity specified by the plurality of image data having different observed times .
The transmission signal is a microwave signal transmitted from an antenna installed at one place,
The program according to claim 1, wherein the wavelength of the microwave signal is shorter than the wavelength of the ultrashort wave .

Images