JP2003075528A - Wireless detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable also a sweep unit processing to be performed at the subsequent stage by improving the correspondence relationship between the current data and the past data. SOLUTION: The current data obtained from a buffer memory 13 are sweep data and have correspondence relationship to an antenna relative azimuth. When data after correlation processing created by a write data creating part 14 according to the current data and the past data are written to a scan memory 17 or 18, addressing is performed according to the coordinate system fixed to a loaded ship, thereby retaining the correspondence relationship to the antenna relative azimuth. When the past data are read out of the scan memory 17 or 18 to the write data creating part 14, a read address adjusted according to the turning round amount and the moving amount of the loaded ship from the past to the current time is used. The current data and the past data in the write data creating part 14 become data related to the same point in the coordinate system fixed to the global surface to improve the correspondence relationship. Since the correlated data corresponds to sweep, CFAR processing in sweep unit can be carried out at a sweep data processing part 15 so as to improve the image quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless detection device mounted on a moving body and wirelessly detecting the presence and position of other objects around the moving body, for example, a marine radar device.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional radar device for a ship. The marine radar device shown in this figure is
A receiver 1 that receives an echo signal and performs processing such as amplification, an A / D converter 2 that converts the echo signal received by the receiver 1 into digital data, and digital data obtained from the A / D converter 2, that is, an echo For example, a buffer memory 3 that holds data for one sweep, a write data creation unit 4 that creates write data based on echo data on the buffer memory 3, that is, current data and data on the frame memory 6, that is, past data, and a frame. A write address generation unit 5 that addresses a read source of past data on the memory 6, that is, a write destination of write data, a frame memory 6 that provides a storage space corresponding to the screen of the display unit, and a read of data supplied to the display unit. A read address generator 7 for addressing the original is provided. Further, although not shown in the drawing, a transmission unit for generating a detection signal, an antenna for wirelessly transmitting the detection signal and receiving a reflection or echo signal from another object existing in the vicinity, data read from the frame memory 6 A display device for displaying the detection result based on the above is also provided.

In the radar system for a marine vessel of the pulse radar type, the transmitting section generates a transmission pulse at a predetermined cycle and radiates a radio frequency signal modulated by the transmission pulse from the antenna as a detection signal. The receiver 1 receives an echo signal corresponding to the detection signal. This one-time transmission / reception is called one sweep. Further, the antenna is installed at a place with a good view on the ship on which the antenna is mounted. The directional direction of the antenna orbits at a predetermined speed in a substantially horizontal plane due to rotational driving by a motor or the like. One rotation of the pointing direction with respect to the loading destination ship (for example, from the time when facing the bow direction to the time when facing the next bow direction) is called one scan. A large number of sweeps are usually included in one scan in order to detect the presence or absence of other objects such as a ship or the land around the ship on which they are mounted and to accurately detect the position of the object. The A / D conversion unit 2 in the latter stage of the reception unit 1 generates echo data by A / D converting the echo signal output from the reception unit 1, and the buffer memory 3 in the subsequent stage converts the echo data into For example, the data is temporarily stored for one sweep or for a plurality of sweeps while maintaining the reception order.

As described above, the data in the buffer memory 3 essentially conforms to the polar coordinate system because it is associated with any sweep, that is, the antenna pointing direction (θ) and the reception order, that is, the distance (R). It can be said to be data. As a display unit, a raster scan type display unit that scans a screen according to an XY coordinate system is used, and a P (to be described later) is displayed on the screen.
In order to display the detection result according to the PI method, it is necessary to coordinate-convert the data in the buffer memory 3 from the polar coordinate format to the rectangular coordinate format. This coordinate conversion can be realized by using the frame memory 6 which is a memory that provides a storage space corresponding to the screen of the display and controlling the write address for the frame memory 6. That is, in principle,

## EQU1 ## X = X0 + R × sin θ Y = Y0 + R × cos θ where (X0, Y0): PPI center X, Y: horizontal and vertical coordinates of the screen θ: polar coordinates (R, θ) calculated based on the upward direction of the screen ) To Cartesian coordinates (X.
Since it can be converted to Y), if this orthogonal coordinate (X, Y) is used as a write address of the frame memory 6 or the write address is generated using this, a write address conforming to the orthogonal coordinate system can be obtained. it can. The data in the buffer memory 3 is written in the frame memory 6 according to the write address specified by the write address generating unit 5, after the write data creating unit 4 performs a later-described correlation process and the like. The read address generator 7 generates a read address in synchronization with the display clock and in the raster scan order. Data is read from the frame memory 6 according to the read address and used for display on the screen of the display.

Further, as a detection result display method in a ship radar device, a PPI method is widely used in which the presence and position of other objects on the surface of the water around the ship where the ship is mounted are displayed in a plane. The PPI method has several display modes. First, the display mode in which the ship is placed at the center (PPI center) of the display screen according to the PPI method is called the relative motion mode, and the display mode in which the screen is fixed to the surface of the earth is called the true motion mode. In addition, the display mode in which the upward direction of the display screen is north is the north-up mode, the display mode in which the upward direction is the course direction of the ship is the course-up mode, and the display mode in which the upward direction is the ship's bow direction is the head-up mode. Call. Normally, there is a relative movement / true movement mode and a north-up / course-up / head-up mode.
Use in appropriate combination according to the monitoring target and monitoring purpose. In the figure, "display mode data" given to the write address generator 5 is data indicating a display mode selected by the user through an operation unit (not shown) or the like. According to the display mode data, the write address generator 5 switches the antenna pointing direction used to generate the write address.

For example, "antenna direction data" in the figure
Is data indicating the antenna directing direction expressed with reference to the bow of the ship on which the ship is mounted (more generally defined as the direction of fixing the hull), and is used to drive the rotation detector attached to the antenna or the antenna. It is based on a signal obtained from the control system of the motor. The “own ship true azimuth data” is data indicating the bow direction of the ship on which the ship is to be mounted, based on the azimuth fixed on the earth surface, for example, north, and is based on signals obtained from onboard equipment such as a gyro compass. When the head-up mode is commanded by the display mode data, the antenna azimuth data is used to generate the write address. When the north-up mode is commanded, the antenna bearing data is converted to the earth surface reference based on the ship's true bearing data and used for write address generation. When the course up mode is commanded, the angle (azimuth) of the course of the ship in the earth surface fixed coordinate system is further added.

In the illustrated marine radar device,
The write data creation unit 4 performs correlation processing on the data in the buffer memory 3 using the data in the frame memory 6, and then writes the data in the frame memory 6. For example, when writing the data in the buffer memory 3 to the frame memory 6, the data written in the previous scan or the like (“past data” in the figure) is written according to the write address specified by the write address generation unit 5. The data is read from the frame memory 6 to the write data creation unit 4. The write data creation unit 4 weight-combines this "past data" with the data ("current data" in the figure) on the buffer memory 3, for example. The resulting data (“created data” in the figure) is the write address generator 5
The data is written in the frame memory 6 according to the write address designated by. Through such processing, the correlation processing for suppressing the clutter component in the data written in the frame memory 6 and the movement trajectory processing for accumulating the data regarding the movement trajectory of another object in the frame memory 6 can be realized. The specific processing in the write data creation unit 4 is
Determine according to the desired function.

As an improvement to the device shown in FIG. 4 (hereinafter "conventional technique"), a device described in Japanese Patent Publication No. 6-93019 (hereinafter "prior art") has been proposed.
In the prior art, the role of the frame memory 6 in the prior art is divided into two types. That is, first, the frame memory 6 in the prior art is used for (1) a data supply source for the display device, (2) polar-to-orthogonal coordinate conversion in cooperation with the write address generator 5, and (3) correlation processing. It has multiple roles such as the supplier of "past data". The conventional technique has a problem caused by the frame memory 6 playing these different roles at the same time. For example, when the head-up mode is designated as the display mode, a displacement between the “past data” and the “current data” in FIG. Directional differences occur, making the correlation process inaccurate. In the prior art, in order to solve this problem,
The frame memory is divided into a correlation processing memory and a display memory. In the prior art, the correlation processing result for the "current data" is stored in the address for the correlation processing memory at a predetermined azimuth (north) reference address, and for the display memory in accordance with the designated display mode. I am writing in. Data corresponding to “past data” in FIG. 4, that is, data used for correlation processing is read from the correlation processing memory. In general, according to such a principle, the prior art avoids the conflict between the roles (1) and (3) described above, including the inaccuracies in the correlation processing due to the turning.

[0009]

However, both the correlation processing memory and the display memory in the prior art have the above-mentioned role (2), that is, the polar → orthogonal coordinate transformation. That is, although there is a difference that the memory for correlation processing is in a so-called north (coarse) up mode and the memory for display stores data in a designated display mode, both adopt a storage form corresponding to the PPI screen. There is.

In other words, among the properties held by the received echo signal and by extension, the "current data", the property of having a correspondence relationship with a specific sweep is that the display memory also has the property of having a correspondence with a specific sweep. It is also lost above. On the other hand, the received signal, and thus the “current data”, has a correspondence relationship with the sweep in the order of arrival and the order on the buffer. The correlation processing in the prior art uses the "current data" that exactly corresponds to the sweep, and uses the "past data" that has lost the strict correspondence with the sweep at the time of writing to the memory for correlation processing. Since the processing is executed, the accuracy of the correlation processing easily deteriorates. In addition, there is a possibility that the “past data” to be used for the correlation processing does not exist in the correlation processing memory, so that it is necessary to fill in the holes. These problems are particularly noticeable in areas where the space between adjacent sweeps is small, such as in the vicinity of the target ship (more generally, a moving body), which is easily affected by the turning (turning) and movement of the ship. Become. These problems also occur in the conventional technology.

The present invention has been made as a problem to solve such a problem, and from a point where an echo signal ("current data") is obtained, as in the case of correlation processing and movement trajectory processing. In processing applied to current data based on echo signals ("past data") obtained in the past, it is possible to prevent deterioration of processing accuracy due to collapse of correspondence between current data and past data, and to perform additional processing such as padding. It is one of the purposes to make unnecessary.

[0012]

In order to achieve such an object, the present invention (1) wirelessly transmits a detection signal and wirelessly receives an echo signal corresponding to the detection signal while changing its transmission direction. In a wireless detection device that wirelessly detects the presence and position of another object around a mounting-destination moving body, (2) a memory for storing processed data,
(3) A table for holding the relationship between the true transmission azimuth, which is the detection signal transmission azimuth in the coordinate system fixed to the surface of the earth, and the relative transmission azimuth, which is the detection signal transmission direction in the coordinate system fixed to the mounting destination moving body, (4) The write data creation unit that creates the processed data by combining the current data obtained from the received signal and the past data that is the processed data in the past, and (5) the current to be combined in the write data creation unit. Write the processed data in association with the relative transmission azimuth, and the relative transmission azimuth in association with the true transmission azimuth, in the memory or table, respectively, so that the data and the past data are data relating to the same point on the earth's surface. In addition, by using the true transmission direction and the correspondence between the data-direction and the direction-direction in the memory or table, Characterized in that it comprises a storage control means for reading out data removed by.

As described above, in the present invention, since the correspondence relationship with the relative transmission azimuth is held even for the processed data on the memory, the information regarding the relationship between the true transmission azimuth and the relative transmission azimuth is also stored in the table. Because it is held
During the reading from the memory as past data and the processing in the write data creation unit based on the read past data, the correspondence relationship is not broken and the processing accuracy is not deteriorated. Therefore, good processing results can be obtained in various places, areas, and situations including the vicinity of the mounting destination moving body. In addition, since the correspondence with the relative transmission azimuth (corresponding to the sweep in the example of the radar) is retained also in the processed data, the processed data which is the processing result (for example, the correlation processing result) by the write data creation unit is stored. The circuit in the latter stage of receiving can easily perform processing in units of relative transmission directions (for example, processing in sweep units).
For example, the result of the scan correlation processing by the write data creation unit can be easily (without orthogonal-to-polar coordinate conversion) subjected to CFAR processing in sweep units in the subsequent sweep data processing unit. In this example, in addition to ensuring / improving the accuracy of the scan correlation processing by strictly maintaining the correspondence relation to the sweep, the data quality improving effect of the CFAR processing on the sweep data in which the clutter variance is suppressed by the scan correlation occurs remarkably.

As a means for achieving this, a relatively simple method of devising address control for the memory and tabulating the correspondence relationship between the true transmission direction and the relative transmission direction can be used. Specifically, when writing the processed data to the memory, the storage control unit specifies the write address for the memory based on the relative transmission direction, so that the correspondence relationship that the current data has with the relative transmission direction. , Keep the data retained in memory after processing. On the other hand, the storage control means tabulates the correspondence between the true transmission direction and the relative transmission direction. In reading the past data from the memory, the storage control means, the correspondence relationship with the relative transmission azimuth held by the past data, the correspondence relationship between the tabular true transmission azimuth vs. the relative transmission azimuth, and the current data. Based on the true transmission azimuth according to the above, and the movement of the mounting destination moving body in the elapsed time from when the reception signal which is the basis of the past data is obtained to when the reception signal which is the current data to be combined with the past data is obtained And a read address from the memory is designated according to the turning. As a result, the function of maintaining the correspondence relationship is easily realized.

Further, as in the preferred embodiment of the present invention, it is desirable to provide a plurality of the above memories. In such a case, one of the plurality of memories can be used as a write destination of the processed data and the other can be used as a read source of the past data. Thus, every time the true transmission direction rotates once, the post-processing data write destination is the past data read source, and the past data read source is the post-processing data write destination. Moreover, the roles of a plurality of memories can be exchanged. By doing so, the past data is not lost by overwriting the processed data, and the turning of the mounting destination mobile body can be dealt with more accurately and easily. For example, by setting the storage capacity of the memory to be larger than the capacity capable of storing the processed data obtained during one rotation of the relative transmission direction, the relative transmission direction is set to 1 during one rotation of the true transmission direction. It is possible to appropriately deal with a situation in which the mounting destination moving body rotates more than the rotation, that is, a situation in which the mounting destination moving body turns (turns) in the direction opposite to the detection signal rotation direction. In that case, the storage capacity of the memory is increased in accordance with the maximum turning speed of the mounting destination moving body and the rotation speed of the relative transmission direction with respect to the capacity capable of storing the processed data obtained during one rotation of the relative transmission direction. If set, it is possible to cope with most turning (turning) situations while suppressing the memory capacity.

Further, in the present invention, since the processed data created by the write data creating section has a corresponding relationship with the relative transmission direction, a member (sweep data in this case) provided after the write data creating section. (Referred to as processing unit)
Thus, processing can be performed in units of relative transmission directions. The polar → orthogonal coordinate conversion for PPI display or the like may be performed thereafter. Therefore, the present invention can be understood as the following inventions. That is, the present invention (1) wirelessly detects the presence and position of another object around the mounting destination moving body by wirelessly transmitting a detection signal while changing its transmission direction and wirelessly receiving an echo signal corresponding thereto. In the wireless detection device, the processed data is created by combining (2) a memory for storing the processed data and (3) past data which is the processed data in the past with the present data obtained from the received signal. The write data creating unit and (4) the processed data are written in the memory and the past data is written from the memory so that the present data and the past data to be combined in the write data creating unit are data related to the same point on the surface of the earth. Storage control means for reading, and (5) the processed data created by the write data creation unit for each relative transmission direction and the phase concerned. And sweep data processing unit which processes without destroying the correspondence between the transmission direction, (6)
Coordinate conversion means for converting the processed data processed by the sweep data processing unit from the polar coordinate format to the rectangular coordinate format.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. Since the present invention can be implemented as a ship radar device, an embodiment relating to a ship radar device will be described below. However, the present invention is applicable to a device mounted on a moving body other than a ship and also to a device other than a radar. For wireless detection devices (including those using ultrasonic waves, light, etc.),
Applicable.

FIG. 1 shows the structure of a marine radar device according to an embodiment of the present invention. In the figure, the functions of the receiving unit 11, the A / D converting unit 12, and the buffer memory 13 may be the same as those of the receiving unit 1, the A / D converting unit 2, and the buffer memory 3 in the related art shown in FIG. Further, the functions of a transmitter, an antenna, a display, and the like (not shown) may be the same as those of the conventional one. In the present embodiment, among the functions realized by using the frame memory 6 in the conventional technique shown in FIG. 4, the function of polar → orthogonal coordinate conversion uses the frame memory 16 to generate the second write address. This is realized by the write address control by the unit 26. Further, the function of the correlation / movement locus processing is that the first write address generation unit uses the scan memories 17 and 18 alternately as the data read source and the data write destination and refers to the direction conversion tables 19 and 20. This can be realized by the write address control by 21 and the read address control by the first read address generator 22. Regarding the idea that the function of the conventional frame memory 6 is realized by being divided into a plurality of memories, the present embodiment certainly has a common aspect with the prior art. However, as will be described in more detail below, the present embodiment, and thus the present invention, are based on technical means different from the prior art and, at the same time, produce different effects.

First, the data in the buffer memory 13 represented as "current data" in the drawing is "past data" in the drawing in the write data creating unit 14 according to a predetermined method.
Combined with the data from the scan memory 17 or 18 represented as The illustrated example is an example in which the write data creation unit 14 performs correlation processing (weighted combination processing of both data, etc.), and the data obtained as a result, that is, “data after correlation processing” is the sweep data processing unit 15. Is written in the frame memory 16 via the. The sweep data processing unit 15 is a member that executes, for example, CFAR processing that is filtering for clutter suppression.

The processing executed by the sweep data processing section 15 is that the processing target in the write data creating section 14 and thus the processing result data is in the receiving order rather than the raster scan order, and the coordinate conversion is performed at a later stage. Can be a sweep-based process. This is a process that cannot be executed by the conventional technique. That is, since the data is converted into the rectangular coordinate format by the write address control for the frame memory 6, if the echo data is subjected to the processing in the sweep unit, it must be in a stage before the write data creation unit 4, and the correlation processing and the like are performed. It is not possible to perform processing on the echo data in units of sweeps. On the other hand, in the present embodiment, the echo data subjected to the correlation processing and the like can be processed in sweep units. For example, the effect of the CFAR processing, that is, the false alarm probability reduction effect is obtained by suppressing the clutter variance by the correlation processing and then performing the CFAR processing (suppression of the low frequency fluctuation) in sweep units in the sweep data processing unit 15. Becomes more prominent.

Writing / reading to / from the frame memory 16 is controlled by the second write address generator 26 and the second read address generator 27. The frame memory 16 is a memory related to the address space (X, Y) corresponding to the screen of the display, like the frame memory 6 in the related art. The second write address generation unit 26 generates a write address for the frame memory 16 in accordance with the same arithmetic expression as that described above with respect to the conventional technique, and the second read address generation unit 27 also uses the read address in the conventional technique. Similar to the generator 7, the read address is generated in synchronization with the display clock and in the raster scan order. As a result, the data subjected to the correlation processing in the write data creation unit 14 and the processing such as CFAR in the sweep unit in the sweep data processing unit 15 is written in the frame memory 16, and the PPI on the raster scan type display screen is displayed. The display is realized based on the data on the frame memory 16. Radar image quality is improved over the prior art and the prior art by the processing in units of sweeps (described above) and the correspondence relationship refinement (described later).

In order to generate the write address for the frame memory 16 according to the display mode desired by the user,
The second write address generation unit 26 selects θ to be used according to the display mode specified in the form of display mode data through the operation of the operation unit (not shown) or the like. Thereby,
Various display modes instructed through the display mode data can be supported.

For example, when the head-up mode is instructed, the second write address generator 26 transmits in synchronization with a signal indicating that the antenna directing direction is the reference direction (fixed direction of the ship on which the vehicle is mounted). Direction information, that is, θ, is generated, or antenna azimuth data is used as transmission direction information to generate a write address. These antenna reference direction signals or antenna azimuth data are obtained from the rotation detector attached to the antenna or the control system of the antenna drive motor. When the north-up mode is instructed, the second write address generator 26 uses the true direction data as the transmission direction information to generate the write address for the frame memory 16. The true azimuth data is data indicating the antenna directional direction with reference to a predetermined azimuth on the surface of the earth, for example, north, in other words, data indicating the true azimuth of the antenna directional direction. In the present embodiment, the antenna azimuth data and the own ship The true azimuth data generator 23 generates the true azimuth data based on the true azimuth data. The own ship true azimuth data is data indicating the heading of the ship on which the ship is loaded, which is expressed based on a predetermined azimuth, for example, north, in other words, the data indicating the true direction of the bow of the ship (ship) on which the ship is loaded. It is based on signals obtained from the onboard equipment. When the course up mode is instructed, the second write address generation unit 26 determines θ by using the information on the course of the loading destination ship in addition to the information used in the north up mode.

When the relative motion mode is instructed, the second write address generator 26 fixes the PPI center (X0, Y0) at a predetermined position, for example, an address corresponding to the screen center. When the true motion mode is instructed, the second write address generation unit 26 integrates the moving speed data and the moving direction data over one rotation time given by the one rotation time data, so that the loading from the previous scan is performed. The movement vector of the destination vessel is calculated, and the PPI center (X0, Y0) is moved according to the calculated movement vector. The moving speed data is based on a signal obtained from a moving speed detector on board such as a log (not shown) and indicates the speed of the ship on which the ship is mounted. The moving direction data is data indicating the moving direction of the ship on which the ship is mounted, which is expressed based on a predetermined direction on the surface of the earth, for example, north, and is based on a signal obtained from the on-board moving direction detector. The one-rotation time data is data representing a measurement value of a time required for the antenna pointing direction to make one rotation with respect to a predetermined azimuth on the surface of the earth, for example, north, and the rotation time measurement unit 2
5 is generated.

On the other hand, in this embodiment, scan memories 17 and 18 and azimuth conversion tables 19 and 20 are provided as memories in addition to the frame memory 16. The scan memories 17 and 18 are alternately write destinations of data created by the write data creating unit 14, for example, “data after correlation processing”. The scan memories 17 and 18 are alternately read sources of "past data". The "past data" referred to in the present embodiment is the data written as "data after correlation processing" one rotation time before the antenna pointing direction in the true azimuth direction. Note that it will not always be the same as the data before the scan.
The first write address generation unit 21 and the first read address generation unit 22 specify the write address of “data after correlation processing” and the read address of “past data”, respectively.

Scan memory 17 and scan memory 18
Exchanges the role of writing "data after correlation processing" and the role of reading "past data" for each rotation of the antenna pointing direction in the true direction. For example, assume that the scan memory 17 is a write destination of “data after correlation processing” and the scan memory 18 is a read source of “past data” at an arbitrary time point. After that, when the antenna direction is true and the antenna pointing direction is a predetermined direction in the coordinate system fixed to the earth surface, for example, north, the scan memory 1
8 is a write destination of "data after correlation processing", and the scan memory 17 is a read source of "past data".
After that, when the antenna pointing direction makes one full turn in the true azimuth direction and faces the predetermined azimuth direction again, for example, north, the scan memory 17 becomes the writing destination of the "data after correlation processing" and the scan memory 18 becomes the reading source of the "past data". become. This role exchange is performed by detecting one rotation in the rotation time measuring unit 25 or by memory selection (address designation) by the first read address generating unit 22 or the like synchronized with one rotation of true direction data.

As shown in FIG. 2, the scan memories 17 and 18 are assigned addresses corresponding to the coordinate system fixed to the ship on which they are mounted. In the figure, "azimuth direction" is
It is an address component based on the bearing of the loading destination ship, that is, a relative bearing, and the “distance direction” is an address component based on the distance from the loading destination ship. The addresses of the scan memories 17 and 18 are allocated such that a predetermined number of bytes starting from the address 0 is in the bow sweep, the next predetermined number of bytes is in the next sweep, and so on. Since the starting point of the "azimuth direction" is fixed in the bow direction, it can be said that the addresses of the scan memories 17 and 18 are based on the coordinate system fixed to the loading ship. However, the read address of the data to the scan memories 17 and 18 is
It is generated by using the true direction of the antenna pointing direction and the movement amount of the ship on which the ship is mounted in the earth surface fixed coordinate system.

Since the addresses of the scan memories 17 and 18 are in the fixed format of the destination ship, the write address for writing the "data after correlation processing" is the "current data" which is the target of correlation processing. Sweep number, that is, the relative direction of the antenna pointing direction, and the buffer memory 1
It may be generated based on the position of the data on 3 or the time required from transmission to reception (distance to the reflecting object). If the relative azimuth is θcr and the distance is Rc, the write address writeadd of “data after correlation processing” is

## EQU00002 ## writeadd = .theta.cr.times.n + Rc. Note that n is the number of data included in one sweep. As can be understood from this equation, the first write address generation unit 21 may repeat the operation of incrementing the write address writeadd according to the distance order, that is, the reception order for each sweep.

On the other hand, since the movement and turning of the loading vessel cannot be ignored while the antenna pointing direction makes one revolution in the true direction, the movement and turning of the "past data" are included in the read address, so that More complicated formulas are required for calculation. First, the amount of movement (Δ
X, ΔY), the first read address generator 2
2 synchronizes with one rotation detection in the rotation time measuring unit 25 and integrates the moving speed data and the moving direction data.
In addition, true azimuth data indicating the true azimuth of the antenna pointing direction is obtained from the true azimuth data generator 23. In addition to the true azimuth θct given by the true azimuth data, the true azimuth (= true of the antenna pointing direction) of the reflecting object at the time of acquisition of the echo data related to the “past data” is calculated from the distance Rc and the movement amount (ΔX, ΔY). Azimuth) θpt and distance Rp

## EQU3 ## θpt = arctan (Xp / Yp) Rp = (Xp ² + Yp ² ) ^1/2 However, Xp = Rc · cos θct + ΔX Yp = Rc · sin θct + ΔY

As shown in FIG. 2, since data is stored in the scan memory in accordance with the address relating to the relative azimuth, "past data" relating to the same position as the reflecting object position where "current data" is obtained is stored. In order to obtain, not the true azimuth θpt of the reflecting object at the time of acquiring the echo data related to the “past data” but the relative azimuth θpr of the reflecting object at the time of acquiring the echo data related to the “past data”, that is, the bow direction and the like. It is necessary to obtain the reference azimuth. The azimuth conversion tables 19 and 20 are means for that purpose, and in parallel with the writing of the "data after correlation processing" to the corresponding scan memory, the true azimuths of the sweeps related to the "data after correlation processing" Relative azimuth data is stored according to the address corresponding to the data. The azimuth conversion tables 19 and 20 exchange their roles in synchronization with one rotation of the true azimuth data. That is, relative azimuth data is written in the azimuth conversion table in which the corresponding scan memory is the write destination of “data after correlation processing” according to the address corresponding to the true azimuth data, and the corresponding scan memory is categorized as “past data”. Relative azimuth data is read from the azimuth conversion table, which is the source of "data", according to the address corresponding to the true azimuth data.

The first read address generating section 22 uses the above-mentioned formula to obtain the address relating to the true azimuth θpt from the azimuth conversion table corresponding to the read source scan memory of the "past data" of the azimuth conversion tables 19 and 20. The relative azimuth θpr stored in is read. The first read address generation unit 22 reads the relative azimuth θpr.
And the distance Rp obtained by the above equation,

[Formula 4] readadd = θpr × n + Rp The read address read of “past data” read
Specify d.

FIG. 3 shows an example of usage of the scan memories 17 and 18 and the direction conversion tables 19 and 20 in this embodiment. In this figure, the left half, that is, (a), shows the contents of the scan memory 17 and the azimuth conversion table 19, and the right half, that is, (b), shows the scan memory. 18 and the contents of the direction conversion table 20. (1) shows the state of the first rotation of the antenna pointing direction in the true direction, (2) shows the state of the second rotation, (3) shows the state of the third rotation, and (4) shows the state of 4
The state of the rotation eye is shown respectively. In the figure, “scan eye” is described, but this is for intuitive understanding. Strictly speaking, the role exchange between the scan memories in the present embodiment is performed every scan, that is, in the relative azimuth when the antenna pointing direction is changed. It is not performed every one rotation but every time the antenna pointing direction is rotated in the true direction. Further, for ease of explanation, it is assumed that no information is stored in the scan memory or the orientation conversion table before the illustrated operation is started.

First, in the first rotation, "past data"
Is not stored in any scan memory,
Instead of "data after correlation", "current data"
While being supplied to the sweep data processing unit 15, it is written in either one of the scan memories, for example, the scan memory 17. In the example shown in the figure, at the start of writing (antenna pointing direction = north), the bow of the destination ship is not north but slightly northwest, so the antenna pointing direction is slightly shifted clockwise with respect to the bow direction. There is.
The “current data” is the write address w shown in the equation above.
It is written in the scan memory 17 in accordance with writeadd. That is, the write operation is repeated, such as writing data of a certain sweep according to the arrow in the “distance direction” in the figure, moving to the next sweep along the arrow in the “azimuth direction”, and writing according to the arrow in the “distance direction”. . In parallel with this, the relative azimuth data is written in the azimuth conversion table 19 according to the address determined by the true azimuth data for each sweep. The numbers "0" and "40" in the figure
"95" is only an example of an address value when the true direction data is expressed by 12 bits or more.

When the antenna directing direction makes one full turn in the true direction to the north, as shown in FIGS. 3B and 3B, the scan memory 18 and the direction conversion table 20 are replaced by the scan memory 17 and the direction conversion table 20. Will play the same role that he had. However, since the data that should be “past data” is already stored in the scan memory 17, the write data creation unit 14 can execute the correlation processing and the like. Therefore, not the “current data” but the “data after the correlation process” is written in the scan memory 18. That is, the write data creation unit 14
The data stored in the scan memory 17 in the first one rotation is received as "past data", and "current data" is received.
With respect to, correlation processing is performed based on “past data”. The “data after correlation processing” obtained as a result is supplied to the scan memory 18 and the sweep data processing unit 15. When reaching the right end ("maximum sweep number") of the scan memory 18 in the middle of the writing of the second rotation, the remaining sweep data is written back to the address 0 side, that is, the left end in the drawing. On the other hand, with respect to the scan memory 17 that is the source of reading the “past data”, the data corresponding to the position of the reflecting object relating to the “current data” is read as the “past data”, A read address is generated by including movement and turning, and reading is performed.

Through this operation, in the present embodiment,
By preventing the breakage of the data correspondence caused by the data overwriting due to the movement / turning of the loading destination ship or the adjacent sweep, accurate correlation processing, for example, scan correlation processing is realized. The processing in sweep units and the retention of the data correspondence could be realized because the read / write of the scan memories 17 and 18 is performed by the address based on the fixed coordinate system of the mounting destination ship, and the scan memories 17 and 18 Which of the read destinations (= which is the write destination) is switched based on the true azimuth of the antenna pointing direction,
Azimuth conversion table 19 as means for realizing that
And 20 are used. In the correlation processing in the write data creation unit 14, "current data"
Since the accurate correspondence between "and past data" is realized, the accuracy of the correlation processing is high. Since the accuracy of the correlation process itself is high as described above, the sweep unit process in the sweep data processing unit 15, for example, the sweep unit CFAR process can be suitably executed.

Further, in the example in which data is written in the memory for correlation processing in accordance with the predetermined azimuth (north) reference address as in the prior art, when the ship on which the ship is mounted turns, for example, during one scan, "current data" is obtained. A situation may occur in which "past data" corresponding to the obtained true direction does not exist in the memory for correlation processing. In such a case, the prior art either gives up the execution of the part relating to the "current data" of the correlation processing, or else, interpolates / fills in the data for another direction on the memory for the correlation processing. , And create "past data" at any time, or either process will be necessary. On the other hand, in this embodiment, data is written in the scan memories 17 and 18 with reference to the bow direction or the like, that is, according to the relative azimuth reference address. "Current data" due to the nature of being received
Is always associated with the relative orientation of the antenna pointing direction, so there is no "past data" in scan memories 17 and 18 that corresponds exactly to "current data".
This situation does not occur due to the turning of the ship on which it is mounted. Therefore, the problem of loss of the data correspondence relationship due to the turning of the loading destination ship does not occur in this embodiment.

As shown in FIGS. 2 and 3, the storage capacities of the scan memories 17 and 18 in this embodiment are set to be larger than one scan, that is, one rotation of the antenna pointing direction in the relative direction. Has been done. This is because, when the turning direction of the loading vessel and the direction of rotation of the antenna pointing direction are opposite, the number of sweeps during one full rotation of the antenna pointing direction exceeds the number of sweeps per scan. The excess of the storage capacity for the number of sweeps per scan (the storage capacity from "Forward direction (second time)" to "Maximum sweep number" in Fig. 2) is the estimated maximum turning speed ω1 of the target ship. It is desirable to determine it based on the rotation speed ω2 in the antenna pointing direction.
Specifically, antenna azimuth resolution x (1 + ω2 / ω1)
Each of the scan memories 17 and 18 has a storage capacity corresponding to. By doing so, it is possible to save almost all the data while suppressing the storage capacity used, regardless of the turning or the like of the loading destination ship. The direction at the time of role exchange of the scan memory is used as the reference direction of the relative azimuth, for example, the bow direction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a ship radar device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a configuration of a scan memory in this embodiment.

3A and 3B are views for explaining the operation of the present embodiment by way of example, FIG. 3A shows the contents of a scan memory 17 and an orientation conversion table 19, and FIG.
6A and 6B are diagrams showing the contents of the azimuth conversion table 20 and the azimuth conversion table 20 in accordance with the scan orders (1) to (4).

FIG. 4 is a block diagram showing a configuration of a radar device for a ship according to a related art.

[Explanation of symbols]

11 reception unit, 12 A / D conversion unit, 13 buffer memory, 14 write data creation unit, 15 sweep data processing unit, 16 frame memory, 17, 18 scan memory, 19, 20 direction conversion table, 21 first write address generation Section, 22 first read address generation section, 23 true direction data generation section, 24 relative direction data generation section, 25 rotation time measurement section, 26 second write address generation section, 27 second read address generation section.

Claims (5)

[Claims] 1. A wireless detection device for wirelessly detecting the presence and position of another object around a mounting destination moving body by wirelessly transmitting a detection signal while changing its transmission direction and wirelessly receiving an echo signal corresponding thereto. , The memory for storing the processed data and the relative transmission direction which is the detection signal transmission direction in the coordinate system fixed to the mounting destination moving body with respect to the true transmission direction which is the detection signal transmission direction in the coordinate system fixed to the earth surface Table for holding the relationship between the data, the write data creation unit that creates the processed data by combining the current data obtained from the received signal and the past data that is the processed data in the past, and the combination in the write data creation unit The relative transmission direction should be paired so that the current data and past data to be targeted are data related to the same point on the surface of the earth. Paste and post-processing data,
Also, the relative transmission azimuths are written in the memory or the table in association with the true transmission azimuths, respectively, and the true transmission azimuths and the correspondences of the data-to-azimuth and the azimuth-to-azimuth in the memory or the table are used to retrieve the past data from the memory. A wireless detection device comprising: a storage control unit for reading out. 2. The wireless detection device according to claim 1, wherein the storage control means writes the processed data into the memory by storing a correspondence relationship of the current data with respect to the relative transmission direction. The write address for the memory is specified based on the relative transmission azimuth so that the processed data created by the write data creation unit based on the above is held in the memory, while the correspondence between the true transmission azimuth and the relative transmission azimuth is specified. When writing to the table and reading the past data from the memory, the correspondence relationship with the relative transmission direction stored in the past data, the correspondence relationship between the true transmission direction and the relative transmission direction on the table, and the current data are stored. Based on the true transmission direction, and after obtaining the received signal that is the basis of the past data, the current data to be combined with the past data is obtained. A wireless detection device characterized in that a read address from a memory is designated according to the movement and turning of the mounting destination moving body in the elapsed time until the reception signal is obtained. 3. The wireless detection device according to claim 2, wherein a plurality of the memories are provided so that one used as a write destination of the processed data and one used as a read source of the past data are provided and stored. Each time the control means makes one revolution of the true transmission direction, the processed data write destination is the past data read source, and the past data read source is the processed data write destination. Thus, the wireless detection device is characterized in that the roles of the plurality of memories are exchanged. 4. The wireless detection device according to claim 2, wherein the storage capacity of the memory is a storage capacity of the memory to which the processed data obtained during one rotation of the relative transmission direction can be stored. A large number of wireless detection devices are set according to the maximum turning speed and the rotation speed of the relative transmission direction. 5. A wireless detection device that wirelessly detects the presence and position of another object around the mounting destination moving body by wirelessly transmitting a detection signal while changing its transmission direction and wirelessly receiving an echo signal corresponding thereto. In (1), a memory for storing processed data, a write data creation unit for creating processed data by combining current data obtained from a received signal and past data which is processed data in the past, and a write data creation unit. Created by the write data creation unit, and storage control means for writing the processed data to the memory and reading the past data from the memory so that the current data and the past data to be combined in the section become data related to the same point on the surface of the earth. For the processed data, keep the correspondence with each relative transmission direction and with the relative transmission direction. In the sweep data processing unit which processes a radio detection device, characterized in that it comprises a coordinate conversion means for converting the processed data processed by the sweep data processing unit from the polar coordinates in the orthogonal coordinate form, a.