Target detection device and radar device

Abstract

To provide a target detector that can accurately detect a target from a sea region, and a radar device.SOLUTION: A map data acquisition unit 94 acquires vector form map data from a map database 92 on the basis of a current position, and a shoreline data generation unit 95 generates raster form shoreline data on the basis of the map data. A sea region data generation unit 96 fills a region in contact with a sea region in the shoreline data, and extracts the filled region to generate sea region data. A sector range extraction unit 97 extracts a range corresponding to one sector from the sea region data, and a B scope conversion unit 98 converts the sea region data corresponding to one sector into a B scope form. A mask processing unit 99 overlaps B scope form sector data generated by a sector data generation unit 91 and the sea region data corresponding to one sector to extract a target present in the sea region.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a target detection device and a radar device that perform target detection based on an echo reflected by a radar wave.

Background Art

[0002] A radar device mounted on a ship or the like transmits radar waves in all directions around the ship, receives the echo of the radar wave reflected by a target by an antenna, and detects the position (azimuth and distance) of the target based on the received echo. Specifically, while the antenna rotates in the horizontal plane, pulse-shaped radio waves are transmitted as radar waves, and sweep processing for receiving an echo reflected by the radar wave is repeatedly performed. Then, based on the echo received in each sweep processing, targets (other ships, floating objects, buoys, etc.) existing around the ship are detected.

[0003] In such a marine radar device, fixed objects such as land, mountains and buildings on land may be erroneously detected as targets. In order to prevent such false detections, a radar device that controls so as not to detect targets in the land portion is known (for example, see Patent Document 1). In this radar device, based on the nautical chart data centered on the position of the ship itself and the transmission period and transmission azimuth of the radar wave, for each sweep processing when the antenna is facing the direction of land, a blocking gate signal is generated at the time position corresponding to the distance range of the land portion, and based on this blocking gate signal, target detection is not performed in the distance range of the land portion of the echo.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the radar system described in Patent Document 1, in order to block target detection from land, a blocking gate signal must be generated that matches the shape of the coastline. However, if the coastline has a very complex shape, the blocking gate signal may be misaligned with the coastline. If the blocking gate signal is misaligned with the coastline, an area that is actually sea may be mistakenly identified as land, or an area that is land may be mistakenly identified as sea.

[0006] Therefore, the present invention aims to provide a target detection device and a radar device that can accurately detect targets from the sea. [Means for solving the problem]

[0007] To solve the above problems, the invention described in claim 1 is: It is carried on board a ship, The system repeatedly performs a sweep process in which pulsed radar waves are transmitted while the antenna is rotated, and echoes of the reflected radar waves are received. Thread A target detection device used in a radar device, which detects a target based on the echo, comprising: sector data generation means that divides the rotation of one scan of the antenna into a plurality of sectors, and generates B-scope format sector data from a plurality of sweep data generated based on the echo for each sector; a map database that stores vector format map data; position detection means that detects the current position of the vessel; map data acquisition means that, based on the detected current position, acquires vector format map data of a predetermined range including the current position from the map database; coastline data generation means that extracts data indicating the coastline from the acquired vector format map data and generates raster format coastline data based on the extracted data; sea area data generation means that, in the coastline data, fills in areas that are adjacent to the coastline and not closed, and generates sea area data based on the filled areas; and from the sea area data, the range corresponding to the sector data As a sector rangeThe target detection device is characterized by comprising: a sector range extraction means; a B-scope conversion means for converting the sea area data of the sector range into B-scope format; and a masking means for superimposing the sea area data of the sector range in B-scope format with the sector data and extracting the region of the sector data that overlaps with the sea area data of the sector range.

[0008] The invention described in claim 2 is a radar device that transmits pulsed radar waves while rotating an antenna and repeatedly performs a sweep process to receive echoes reflected by the radar waves, and is characterized by comprising the target detection device described in claim 1. [Effects of the Invention]

[0009] According to the inventions described in claims 1 and 2, since targets are detected on a sector-by-sector basis, it is possible to detect targets from the sea area with higher accuracy compared to conventional techniques that perform processing for each sweep. Furthermore, it is possible to reduce the processing load compared to detecting targets from scan data for one rotation of the antenna. In addition, since vector-format map data is used, coastline data can be easily extracted, and raster-format coastline data can be generated accurately and quickly. Furthermore, since sea area data is generated by filling in the coastline data, it is possible to determine the sea area with high accuracy. Moreover, by overlaying the sea area data of a sector range converted to B-scope format with sector data also in B-scope format, it is possible to extract only targets within the sea area, thereby suppressing the misdetection of land or fixed objects on land as targets. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing the schematic configuration of a radar device according to an embodiment of the present invention. [Figure 2] This block diagram shows the functional configuration of the target detection unit as shown in Figure 1. [Figure 3]This is an explanatory diagram of one sweep, sector, and one scan of radar waves. [Figure 4] This figure shows an example of sector data in B-scope format. [Figure 5] This diagram shows the process of generating raster-format coastal data from vector-format map data. [Figure 6] This diagram shows the process of generating marine area data from coastline data. [Figure 7] This figure shows the marine region data for a sector range extracted from marine region data. [Figure 8] This diagram shows the process of extracting targets based on marine area data and sector data. [Figure 9] This is a flowchart showing the procedure for target detection. [Modes for carrying out the invention]

[0011] The present invention will be described below based on the illustrated embodiments.

[0012] Figure 1 is a block diagram showing the schematic configuration of a radar device 1 according to an embodiment of the present invention. The radar device 1 is mounted on a ship, for example, and includes an antenna 2, a transmitting and receiving unit 3, an A / D conversion unit 4, a coordinate transformation unit 5, a sweep data storage unit 6, a display control unit 7, a display unit 8, and a target detection unit (target detection device) 9.

[0013] Antenna 2 repeatedly performs a sweep process that includes transmitting pulsed radar waves while rotating in the horizontal plane and receiving echoes of radar waves reflected from the target. The transmitting / receiving unit 3 generates radar waves to be transmitted from antenna 2 and inputs them to antenna 2. The transmitting / receiving unit 3 also detects and amplifies the echoes received by antenna 2 to generate an analog echo signal.

[0014] The A / D conversion unit 4 A / D-converts the echo signal output from the transmission / reception unit 3 to generate digital sweep data. The coordinate conversion unit 5 converts the sweep data in the polar coordinate system output from the A / D conversion unit 4 into sweep data in the rectangular coordinate system in which the azimuth θ and the distance R are represented by rectangular coordinates.

[0015] The sweep data storage unit 6 stores the sweep data for one sweep output from the coordinate conversion unit 5, and outputs the sweep data for one sweep to the display control unit 7 and the target detection unit 9 until the next sweep process is executed and new sweep data is input. The target detection unit 9 detects a target based on the sweep data, and outputs the detection result to the display control unit 7.

[0016] The display control unit 7 generates a B-scan format radar image based on the sweep data for one scan. Also, the display control unit 7 generates a graphic image for target identification etc. based on the target detection result of the target detection unit 9. The graphic image for target identification is a graphic image for displaying the identification name etc. of the target detected by the target detection unit 9, and is displayed superimposed on the radar image. The display unit 8 is a display having a function of displaying the radar image and the graphic image etc. generated by the display control unit 7, and is constituted by, for example, a liquid crystal display.

[0017] As shown in FIG. 2, the target detection unit 9 includes a sector data generation unit (sector data generation means) 91, a map database 92, a position detection unit (position detection means) 93, a map data acquisition unit (map data acquisition means) 94, a coastline data generation unit (coastline data generation means) 95, a sea area data generation unit (sea area data generation means) 96, a sector range extraction unit (sector range extraction means) 97, a B-scan conversion unit (B-scan conversion means) 98, a mask processing unit (mask processing means) 99, and a threshold determination unit 100.

[0018] The sector data generation unit 91 generates sector data based on the sweep data for one sector output from the sweep data storage unit 6. Here, as shown in Figure 3, if one transmission and reception from the antenna 2 to the reception of the echo is considered one sweep, and one rotation of the antenna 2 is considered one scan, then one scan contains many sweeps, i.e., sweep data. The sector data generation unit 91 divides the rotation of one scan of the antenna 2 into multiple sectors (for example, sector S-1, sector S, sector S+1, etc.), and generates B-scope format sector data in which multiple sweep data within the sector are arranged for each sector.

[0019] Figure 4 shows an example of sector data generated by the sector data generation unit 91. The sector data 91a consists of multiple sweep data Swp units (one sector) arranged along the vertical axis, with each sweep data Swp unit extending in the horizontal direction. Each sweep data Swp unit is divided into multiple cells C based on its distance from the antenna 2, and each cell C stores cell data indicating the signal strength of the echo signal. As a result, the sector data 91a consists of multiple cells C arranged in a matrix, with the distance R and azimuth θ indicated in a Cartesian coordinate system. The sector data generation unit 91 outputs information regarding the azimuth θ range of the generated sector data to the sector range extraction unit 97.

[0020] Map Database 92 is a database that stores map data in vector format. As is well known, in vector format map data, a map is represented by point data and line data connecting two or more point data points. The location of the point data is indicated by latitude and longitude.

[0021] The position detection unit 93 is a device that detects position information from a Global Navigation Satellite System (GNSS) such as GPS. The position detection unit 93 detects the current position of the vessel equipped with the radar device 1 and outputs its position information (latitude and longitude) to the map information acquisition unit 94.

[0022] The map data acquisition unit 94 acquires map information for a predetermined range, including the ship's current position, from the map database 92 based on the position information received from the position detection unit 93. The map database 92 stores map data divided into multiple blocks, for example, for each predetermined latitude and longitude, and the map data acquisition unit 94 acquires map information for the block including the ship's current position. The map data acquisition unit 94 outputs the acquired map data to the coastline data generation unit 95.

[0023] The coastline data generation unit 95 extracts data indicating coastlines from the acquired vector-format map data and generates raster-format coastline data based on the extracted data. As shown in Figure 5, the coastline data generation unit 95 extracts data indicating coastlines (latitude and longitude indicating coastlines L1, L2, L3, and L4) from the vector-format map data Md represented by latitude and longitude, and generates raster-format coastline data Cd based on the extracted coastline data. The coastline data generation unit 95 outputs the generated coastline data Cd to the sea area data generation unit 96.

[0024] The sea area data generation unit 96 fills in the areas enclosed by coastlines in the coastline data and generates sea area data based on the filled areas. Specifically, as shown in Figure 6, the sea area data generation unit 96 fills in the areas in raster-format coastline data Cd that are adjacent to coastlines L1 to L4 and not closed by coastlines L1 to L4. In order to reliably fill in the sea area, it is preferable to fill in the area from the position of the ship outwards, for example. In Figure 6, the area Pa with diagonal lines is the filled area.

[0025] The marine area data generation unit 96 generates marine area data Sd by extracting only the filled-in area Pa from the coastline data Cd shown in Figure 6. In other words, marine area data Sd is data obtained by removing coastlines L1 to L4 from the coastline data Cd. The marine area data generation unit 96 outputs the generated marine area data Sd to the sector range extraction unit 97.

[0026] The sector range extraction unit 97 extracts a range A1 corresponding to the sector data 91a from the sea area data Sd based on information regarding the range of the azimuth θ of the sector data output from the sector data generation unit 91, and generates the sector range sea area data Sd1 as shown in Figure 7. The sector range extraction unit 97 outputs the generated sector range sea area data Sd1 to the B-scope conversion unit 98.

[0027] The B-scope conversion unit 98 converts the sector-range sea area data Sd1 into B-scope format sea area data Sd2 (see Figure 8). The B-scope conversion unit 98 outputs the generated B-scope format sea area data Sd2 to the mask processing unit 99.

[0028] As shown in Figure 8, the mask processing unit 99 overlays the B-scope format sea area data Sd2 with the sector data 91a and extracts the areas 91b, 91c, 91d, 91e, and 91f that overlap the sea area data Sd2 from the sector data 91a. In this way, by using the sea area data Sd2 and the sector data 91a, it is possible to exclude land and fixed land objects and detect only targets at sea. The mask processing unit 99 outputs the sector data 91a from which areas 91b to 91f have been extracted to the threshold determination unit 100.

[0029] The threshold determination unit 100 compares the cell data and area of ​​regions 91b to 91f extracted from sector data 91a with a preset threshold, and detects it as a target such as another ship, floating object, or buoy if the values ​​are above the threshold. The threshold determination unit 100 outputs the target detection result to the display control unit 7.

[0030] Next, the processing of the target detection unit 9 described above will be explained based on the flowchart shown in Figure 9. The sweep data storage unit 6 outputs sweep data generated based on the transmission and reception of a radar wave by the antenna 2 to the target detection unit 9. The sector data generation unit 91 of the target detection unit 9 generates B-scope format sector data 91a based on the sweep data for one sector output from the sweep data storage unit 6 (step S1).

[0031] The position detection unit 93 detects the current position of the vessel and outputs the detection result to the map data acquisition unit 94 (step S2). Based on the received current position, the map data acquisition unit 94 acquires map data Md for the block containing the current position from the map database 92 and outputs the acquired map data Md to the coastline data generation unit 95 (step S3).

[0032] The coastline data generation unit 95 extracts coastline data from vector-format map data Md and generates raster-format coastline data Cd based on the extracted data. The coastline data generation unit 95 outputs the generated coastline data Cd to the sea area data generation unit 96 (step S4).

[0033] The marine area data generation unit 96 fills in the raster-format coastline data Cd with areas that are adjacent to coastlines L1 to L4 but are not closed by coastlines L1 to L4. The marine area data generation unit 96 extracts only the filled areas Pa from the coastline data Cd to generate marine area data Sd, and outputs the generated marine area data Sd to the sector range extraction unit 97 (step S5).

[0034] The sector range extraction unit 97 extracts a range A1 corresponding to sector data 91a from the sea area data Sd based on the information regarding the azimuth range of the sector data output from the sector data generation unit 91, and generates the sector range sea area data Sd1. The sector range extraction unit 97 outputs the generated sector range sea area data Sd1 to the B-scope conversion unit 98 (step S6).

[0035] The B-scope conversion unit 98 converts the sector-range sea area data Sd1 into B-scope format sea area data Sd2. The B-scope conversion unit 98 outputs the generated B-scope format sea area data Sd2 to the mask processing unit 99 (step S7).

[0036] The mask processing unit 99 overlays the B-scope format sea area data Sd2 with the sector data 91a and extracts the areas 91b, 91c, 91d, 91e, and 91f that overlap the sea area data Sd2 from the sector data 91a. The mask processing unit 99 outputs the sector data 91a from which areas 91b to 91f have been extracted to the threshold determination unit 100 (step S8).

[0037] The threshold determination unit 100 compares the cell data and area of ​​regions 91b to 91f extracted from sector data 91a with a preset threshold, and detects it as a target such as another ship, floating object, or buoy if the values ​​are greater than or equal to the threshold. The threshold determination unit 100 outputs the target detection result to the display control unit 7 (step S9).

[0038] As described above, with the radar device 1 and target detection unit 9 in this embodiment, targets are detected on a sector-by-sector basis, making it possible to detect targets from the sea area with greater accuracy compared to conventional techniques that perform processing for each sweep. Furthermore, it is possible to reduce the processing load compared to detecting targets from scan data equivalent to one rotation of the antenna. In addition, since vector-format map data Md is used, coastline data can be easily extracted, and raster-format coastline data Cd can be generated accurately and quickly. Moreover, since sea area data Sd is generated by filling in the coastline data Cd, it is possible to accurately determine the sea area. Furthermore, by overlaying the sea area data Sd1 of the sector range converted to B-scope format with sector data 91a, also in B-scope format, only targets within the sea area can be extracted, thereby suppressing the misdetection of land or fixed objects on land as targets.

[0039] Although embodiments of this invention have been described above, the specific configuration is not limited to the embodiments described above, and any design changes, etc., that do not depart from the gist of this invention are also included. For example, although the above embodiments were described using a radar system for ships as an example, it is also applicable to other radar systems that scan radar waves. Furthermore, it can be applied to situations where a radar system installed on land detects only land targets, and sea targets are not detected.

[0040] 1. Radar equipment 2 antennas 3. Transmitter / Receiver Unit 4. A / D conversion section 5. Coordinate Transformation Unit 6. Sweep Data Storage Unit 7 Display Control Unit 8 Display 9. Target detection unit (target detection device) 91 Sector data generation unit (sector data generation means) 91a Sector data 92 Map Database 93 Position detection unit (position detection means) 94 Map data acquisition unit (map data acquisition means) 95 Coastline data generation unit (coastline data generation means) 96. Marine Area Data Generation Unit (Marine Area Data Generation Means) 97 Sector range extraction unit (sector range extraction means) 98 B-scope conversion unit (B-scope conversion means) 99 Mask processing unit (mask processing means) 100 Threshold determination unit Md map data Cd Coastline Data Sd Marine Area Data Sd1 Sector Range Sea Region Data Sd2 C-scope format marine area data

Claims

1. A target detection device used in a radar system mounted on a ship, which transmits pulsed radar waves while rotating an antenna and repeatedly performs a sweep process to receive echoes reflected from the radar waves, and which detects a target based on the echoes, A sector data generation means divides the rotation of the antenna for one scan into multiple sectors, and for each sector, generates B-scope format sector data from multiple sweep data generated based on the echo, A map database that stores vector-format map data, A position detection means for detecting the current position of the aforementioned vessel, Map data acquisition means that acquires vector-format map data for a predetermined range including the current location from the map database based on the detected current location, Coastline data generation means for extracting data indicating coastlines from the acquired vector-format map data and generating raster-format coastline data based on the extracted data, A sea area data generation means that fills in areas in the aforementioned coastline data that are adjacent to the coastline and are not closed, and generates sea area data based on the filled areas, A sector range extraction means for extracting a range corresponding to the sector data from the aforementioned sea area data as a sector range, A B-scope conversion means for converting the sea region data of the sector range into B-scope format, A mask processing means that overlays the B-scope format sea area data of the sector range with the sector data and extracts the area of ​​the sector data that overlaps with the sea area data of the sector range, A target detection device characterized by comprising the following features.

2. A radar device that transmits pulsed radar waves while rotating an antenna and repeatedly performs a sweep process to receive echoes reflected from the radar waves, A target detection device according to claim 1, A radar device characterized by the following features.

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