Radar receiver and radar device

Abstract

Radar receiving device (4) comprising: a receiving signal detector (6) for detecting a received signal, in an RO coordinate system, which was received by an antenna (2) rotating in a predetermined cycle; a signal processor (9) for performing signal processing of the received signal according to a distance in the RΘ coordinate system, and outputting the processed signal in the RΘ coordinate system; a PPI-Scope Generator (10) for converting the processed signal from the RO coordinate system to an XY coordinate system and generating a radar image in a PPI-Scope, an A-Scope generator (11) for generating a radar image of the received signal prior to signal processing by the signal processor (9), displayed in an A-Scope; a display output unit (13) for simultaneously displaying the PPI-Scope radar image and the A-Scope radar image on a display unit (16), and a user interface (12) that allows user input, wherein the signal processor (9) performs the signal processing by applying a threshold value to a signal level of the received signal, the threshold value being set according to a distance, and wherein the A-Scope generator (11) generates the radar image by superimposing a threshold curve onto the received signal displayed in the A-Scope, which represents the relationship between the threshold and the distance, wherein the user can adjust or change the threshold curve via the user interface (12) in a state where the threshold curve is displayed on the display unit (16) and wherein the A-Scope Generator (11) generates the radar image, in which the adaptation or modification thereof is represented, wherein the threshold curve contains a plurality of curves, wherein the user interface (12) selects one from the plurality of threshold curves, and wherein the signal processor (9) performs the signal processing by using the threshold curve selected via the user interface (12).

Description

Technical field

[0001] The present invention relates in principle to a radar device and in particular to a configuration to assist in setting a characteristic of the STC (Sensitive Time Control) in the radar device. Background of the invention

[0002] Basically, pulse radar devices transmit pulsed high-frequency signals from antennas and receive reflection signals from target objects in the environment.

[0003] A radar system essentially includes a display device for showing a signal received from an antenna. A user of the radar system can then check the radar image to see if a target is in the vicinity. There are various methods for displaying a received signal from an antenna, such as JP H08-15419 A and JP H05-12640 B2, which disclose an A-scope display and a PPI-scope (Plan Position Indicator) display, respectively.

[0004] In an A-scope display, the received signal is shown on a map by plotting the distances to the target on a horizontal axis and the signal level on a vertical axis. The A-scope display has a resolution sufficient to easily distinguish target echoes from the direction in which the antenna is oriented and is used in tracking radar (JP H05-12640 B2). However, since antennas in radar systems, which are generally used in ships and the like, are always rotating, an A-scope display is of little use for target detection, even if the signal received by the antenna is displayed in real time. Consequently, A-scope displays are rarely used in ship radar systems (see L.10, 7th column of JP H07-27020 B2).

[0005] In a PPI scope display, the signal received from the antenna is represented in a two-dimensional rectangular coordinate system. The PPI scope display has a resolution that allows a user to easily and intuitively determine the position of a target object in a horizontal plane. Consequently, ship radar systems generally use PPI scope displays.

[0006] However, the level of the reflected signal from a nearby target is high, while the level of a signal reflected from a distant object is weak. Therefore, it becomes difficult to interpret the radar image correctly when the radar image in the PPI scope is generated by using the signals themselves, since the interpretation of the echo images is completely different depending on whether the target is near or far.

[0007] Accordingly, in the field of radar devices, so-called STC methods (Sensitive Time Control methods) are used to adjust the levels of the received signals according to the distance to the target object. In particular, the intensity of signals from close range is reduced, while the intensity of signals from greater distances is increased. Such an example of an STC method is disclosed in JP H09-72958 A.

[0008] Consequently, adjusting the STC curve characteristics for simplified display in the PPI-Scope radar image on a radar device display is important. In this regard, the JP H09-72958 A provides a configuration where the STC characteristic can be modified by adjusting a setting while viewing a CRT display screen (the screen displaying the PPI-Scope radar image), thus obtaining an easily recognizable image.

[0009] In a radar system where the echo image of target objects has been cleared of interference data using STC settings, a situation may still arise where an important target object cannot be detected in the radar image. Therefore, it is necessary to adjust the STC settings so that the echo image adequately retains the required target object.

[0010] However, STC processing in the configuration according to JP H09-72958 A does not guarantee that only noise data is eliminated (and that the echo image of the target object is adequately preserved). Consequently, it cannot be directly determined whether the STC adjustment was performed correctly.

[0011] Even with a configuration that allows the STC to be set while the radar image is being observed on the radar screen, as shown in JP H09-72958 A, to display the radar image in such a way that only interference data has been eliminated and the echo image of the target remains, setting the STC requires trial and error. Therefore, setting the STC according to a configuration from JP H09-72958 A is not considered easy.

[0012] Further printed prior art in the present technical field is disclosed in documents US 2009 / 0121923 A1 and JP S58-110869 U. Summary of the invention

[0013] The present invention was made in view of the aforementioned circumstances and aims to provide a radar device in which an STC can be easily adapted.

[0014] According to one aspect of the present invention, a radar receiver is provided which has the following configuration. The receiver comprises a signal acquisition unit, a signal processor, a PPI scope generator, an A-scope generator, a display output unit, and a user interface. The signal acquisition unit detects a received signal in an RO coordinate system, which is obtained from an antenna rotating in a predetermined cycle. The signal processor performs signal processing on the received signal in the RO coordinate system according to a distance and outputs the processed signal in the RO coordinate system. The PPI scope generator converts the processed signal from the RO coordinate system into an XY orthogonal coordinate system and generates a radar image in a PPI scope.The A-scope generator produces a radar image in which the received signal is displayed in an A-scope before being processed by the signal processor. The display output unit shows the PPI-scope radar image and the A-scope radar image simultaneously on a single display unit. The user interface accepts user input.

[0015] By simultaneously displaying the A-scope, based on the unprocessed received signal, and the PPI-scope, based on the received signal processed as described previously, the situations before and after signal processing can be compared. Consequently, it can be easily determined whether the signal processing was performed appropriately.

[0016] According to the invention, the radar receiver is configured as follows. The signal processor performs signal processing by means of a threshold value to determine the signal level of the received signal, the threshold being set according to the distance. The A-scope generator produces the radar image by superimposing a threshold curve, which represents the relationship between the threshold value and the distance on the received signal displayed in the A-scope.

[0017] Consequently, a relationship between the threshold used for signal processing by the signal processor and the signal level of the signal to be processed can be easily determined, in order to ascertain whether the threshold used by the signal processor in the signal processing is set appropriately.

[0018] The radar receiver is configured according to the invention as follows. The user interface allows the user to adjust or change the threshold curve, which is then displayed on the display unit. The A-scope generator produces the radar image that reflects the setting or change.

[0019] As previously described, the threshold curve can be set (or changed) while displayed on the A-Scope screen. This allows for simple and precise adjustment (or modification). The resulting adjustment (or change) is immediately reflected on the display unit, enabling the effect of the setting (or change) to be observed instantly.

[0020] The radar receiver is configured according to the invention as follows. The threshold curve comprises a plurality of threshold curves. The user interface selects one from the plurality of threshold curves. The signal processor performs the signal processing, using the threshold curve selected via the user interface.

[0021] By providing a wide variety of threshold curve options, as described previously, the threshold curve can be set simply by selecting one of these curves. This makes setting the threshold curve straightforward. The numerous selectable threshold curves are displayed superimposed on the A-Scope display, allowing the desired threshold curve to be identified intuitively and easily.

[0022] The A-Scope Generator in the radar receiving device is preferably designed to switch between a display mode between the currently selected threshold curve and the other threshold curve.

[0023] Consequently, an optimal threshold curve can be easily selected from among the multitude of threshold curves.

[0024] The radar receiver is preferably configured as follows. The radar receiver further comprises a threshold determiner for determining whether the signal level of the received signal exceeds the corresponding threshold before signal processing by the signal processor. Based on the threshold determiner's result, the A-Scope generator produces the radar image by switching between a receiving signal element that has a signal level above the threshold and a receiving signal element that has a signal level below the threshold.

[0025] Consequently, detecting the portion of the received signal that exceeds the threshold signal level becomes simpler. This allows for more intuitive threshold curve adjustment.

[0026] The display mode of a receiving signal element of the received signal in the radar device, which is displayed in the A-Scope and which exceeds the signal level of the threshold, is preferably adapted to the display mode of an echo image which is contained in the PPI-Scope radar image and which corresponds to the receiving signal element.

[0027] In this way, the relationship between the echo image displayed in the PPI scope and the received signal displayed in the A scope can be easily understood, and the adjustment of the threshold curve becomes much simpler.

[0028] The A-Scope generator of the radar receiving device is preferably configured to generate the radar image in which the received signal is displayed in a predetermined A-Scope display direction in the A-Scope.

[0029] Consequently, the received signal can be displayed in a specific direction on the A-scope. This allows for a simple visual comparison between the A-scope and the PPI-scope.

[0030] The user interface in the radar receiving device is preferably designed to determine the A-scope display direction on the PPI-scope radar image, which is displayed on the display unit.

[0031] In this way, the desired direction of the received signals to be displayed in the A-scope can be easily and intuitively determined, as well as the relationship between the A-scope and the PPI-scope. This makes setting the threshold curve significantly easier.

[0032] According to another aspect of the present invention, a radar device is provided. The radar device comprises the radar receiving device according to the aforementioned aspect of the invention, an antenna, and a transmitter for transmitting a signal to the antenna.

[0033] According to a further aspect of the present invention, a method for displaying a radar received signal is provided. The method comprises acquiring a received signal in an RO coordinate system, which was received by an antenna rotating in a predetermined cycle. The method further comprises performing signal processing of the received signal according to its distance in the RO coordinate system and outputting the processed signal in the RO coordinate system. The method further comprises converting the processed signal from the RO coordinate system into an XY orthogonal coordinate system and generating a radar image in a PPI scope. The method further comprises generating a radar image in which the received signal is displayed in an A scope before the signal has been processed by means of signal processing.The method further includes the simultaneous display of the PPI-Scope radar image and the A-Scope radar image on a display unit. The method further includes the input of a user command.

[0034] The method for displaying a radar received signal is carried out according to the invention as follows. The signal processing comprises applying a threshold value to the signal level of the received signal, the threshold value being set according to the distance. Generating the radar image in the A-scope comprises superimposing a threshold curve, representing the relationship between the threshold value and the distance, onto the received signal displayed in the A-scope. Brief description of the drawings

[0035] The present disclosure, as illustrated in the figures and the accompanying drawings, is merely descriptive but not limiting, with the same reference signs referring to the same elements.

[0036] They show: Fig. 1 a block diagram representing an overall configuration of a radar device according to a first embodiment of the present invention; Fig. 2a to 2c are diagrams for describing the signal processing (STC) according to the first embodiment; Fig. Figure 3 is a view that represents a display example of a display unit of the first embodiment; Fig. 4 is a view that represents a display example of the display unit where setting an STC curve is unsuitable; Fig. Figure 5 is a view showing another display example of the display unit in a case where setting an STC curve is unsuitable; Fig. 6 is a view of a modification of the first embodiment; Fig. 7 is a view which represents a display example of the display unit of a second embodiment; and Fig. Figure 8 is a block diagram that represents a configuration of a radar device according to a further modification. Detailed description

[0037] A first embodiment is described below with reference to the accompanying drawings. A radar set 1 is a ship pulse radar set with which a ship is equipped. The radar set 1 essentially comprises an antenna 2, a transmitter 3 and a receiver 4 (radar receiver).

[0038] Antenna 2 is connected to transmitter 3 and receiver 4 via a circulator 5. Antenna 2 has a conventional configuration that can rotate 360° in the horizontal plane in a predetermined rotation cycle.

[0039] Transmitter 3 has an oscillator (e.g., a magnetron) and generates a pulse-modeled high-frequency signal at antenna 2 in a predetermined cycle. Consequently, the pulse-modeled high-frequency signal is transmitted by the rotating antenna 2 in a predetermined cycle. In the following description, the signal transmitted by the antenna is referred to as the transmitted signal.

[0040] Furthermore, antenna 2 receives high-frequency signals from the environment for one period after transmitting the signal until it transmits the next signal. In the following description, the signal received by antenna 2 is referred to as the received signal. It should be noted that the received signal may also include a reflection signal element, which is the result of the transmitted signal being reflected back from a target object, resulting in an "unusable signal element," as well as noise and clutter. The received signal is fed into the receiver unit.

[0041] The receiving unit 4 according to this embodiment comprises a preprocessor 6 (receiving signal acquirer), an A / D converter 7, a sample memory 8, a signal processor 9, a PPI scope generator 10, an A-scope generator 11, a user interface 12, a display output unit 13 and a display unit 16.

[0042] The received signal from antenna 2 is output to preprocessor 6. It is known that the distance from the antenna to a target object located in the direction of antenna 2's orientation (the distance R) can be determined based on the received signal from antenna 2 of the pulse radar device. If the direction in which antenna 2 is oriented is Θ, the received signal acquired by preprocessor 6 is a signal in the RΘ coordinate system. Preprocessor 6 performs procedures including amplification, filtering, and down-conversion on the acquired received signal in the RΘ coordinate system and then outputs it to the A / D converter 7.

[0043] The A / D converter 7 sends the received signal in the RO coordinate system, which was input by the preprocessor 6, at a predetermined sampling rate and converts each signal into digital data, outputting it sequentially to the sample memory 8. Consequently, chronological data in the RO coordinate system is obtained, indicating the signal level of the received signal. The chronological data obtained as described above is referred to below as received data. It should be noted that each of the analog and digital received signals can be referred to simply as a "received signal" without any disadvantage to either.

[0044] Sample memory 8 is a memory that can store received data for a sweep. It should be noted that "received data for a sweep" refers to received data recorded within a single period, starting with the transmission signal transmitted by antenna 2 and continuing until the next transmission of the same signal. Sample memory 8 functions as a buffer memory, and as soon as new received data is entered, the old received data is sequentially overwritten with the new data.

[0045] The signal processor 9 reads the received data (sweep data) in the RΘ coordinate system, which is stored in the sample memory 8, sequentially and performs signal processing of the received data according to the distance and outputs the processed data (the processed signal).

[0046] Various methods can be considered "signal processing according to distance," whereby the signal processor 9, according to this embodiment, fundamentally performs STC processing (Sensitivity Time Control). The STC method according to this embodiment is briefly described below with reference to the Fig. 2a to 2c described.

[0047] Fig. Figure 2a shows a schematic representation of the received data (sweep data) for a sweep, which is stored in sample memory 8. The horizontal axis of the Fig. 2a, Fig. 2b and Fig. 2c denotes a time period required from the transmission of the signal to the acquisition of the data by the A / D converter 7, and this time period corresponds to the distance R to the target object that reflected the signal. The vertical axis denotes the signal level of each data point.

[0048] As soon as antenna 2 transmits the signal, and a target object is present in the direction Θ in which antenna 2 is oriented, the reflection signal element from the target object is received by antenna 2. The reflection signal element, which was received from the target object as described above (target object echo), appears as a peak of the signal level in the received data as shown in Fig. 2a shown.

[0049] As in Fig. As can be seen in Figure 2a, received data at close range exhibits a high signal level, while received data from a greater distance exhibits a low signal level. The STC method is an adjustment such that the signal levels of the received data are approximately the same, regardless of the distance.

[0050] The signal processor 9 includes, in particular, an STC curve setting module 14 for setting a curve as described in Fig. 2b shows the STC curve. The STC curve represents a curve for setting a ratio between a threshold value used in the STC method and the distance R (threshold curve).

[0051] The STC curve can, in principle, be any straight or curved curve. However, if the STC curve is a complex one, setting it becomes cumbersome, and such a complex curve may also be unsuitable for the STC procedure. In this embodiment, for ease of setup, a simple curve and curve shape are used, which can be expressed using several parameters. The STC curve setting module 14 generates the STC curve based on stored parameters and outputs the threshold value corresponding to the distance.

[0052] As in Fig. As shown in Figure 2b, the STC curve is set to have a higher threshold at close range and a lower threshold at distant range. The signal processor 9 reads the received data in the RO coordinate system from the sample memory 8 and acquires the thresholds corresponding to the distance R of the received data from the STC curve setting module 14. Furthermore, the signal processor 9 compares the signal level of the received data in the RO coordinate system with the threshold. If the signal level of the received data exceeds the threshold, the signal processor subtracts the threshold from the signal level of the received data and outputs this as the processed data in the RΘ coordinate system. In other words, only the portion of the received data above the STC curve is output by the signal processor 9 as the processed data. An example of the processed data output by the signal processor 9 is shown in Figure 2b. Fig. 2c is shown.

[0053] As long as the STC curve is properly adjusted, the threshold level can be corrected depending on the distance during the STC process. Consequently, as described in Fig. As shown in Figure 2c, the reflection signal element from the target object at a nearby distance and the reflection signal element from the target object at a distant distance can be adjusted to approximately the same level as each other. Furthermore, by setting the STC curve above the levels of the noise and interference signals, the processed data can be freed from unnecessary signal elements, such as noise and clutter, leaving only the reflection signal elements of the target objects.

[0054] The data processed in the RO coordinate system, which was output by the signal processor 9, are input into the PPI-Scope Generator 10 (image generator). The PPI-Scope Generator 10 converts the coordinates of the input processed data from the RO coordinate system into an XY-orthogonal coordinate system to generate a PPI-Scope radar image. It should be noted that a description of a configuration for generating the PPI-Scope radar image by converting the coordinates from the RO coordinate system to the XY-orthogonal coordinate system has been omitted, as such a configuration is already known.

[0055] The PPI-Scope radar image, generated by the PPI-Scope generator 10, is output to the display output unit 13. The display output unit 13 then instructs the display unit 16 to display the input radar image. The display unit 16 is a display unit, such as an LCD (Liquid Crystal Display), and can display a color raster image in a raster format.

[0056] The Fig. Figure 3 shows an example of a screen from display unit 16. As in Fig. As shown in Figure 3, the screen of display unit 16 has a PPI-Scope display area 20, on which the PPI-Scope radar image, generated by the PPI-Scope generator 10, is displayed. The user of radar unit 1 learns about the situation of the target objects in the vicinity by viewing the PPI-Scope radar image displayed in the PPI-Scope display area 20.

[0057] It should be noted that the PPI-Scope radar image displayed in display area 20 was generated based on data after the STC process. Therefore, by appropriately adjusting the STC curve, the radar image displayed in PPI-Scope display area 20 can be simplified.

[0058] The radar device 1 includes the user interface 12 for adjusting various stored parameters in the STC curve setting module 14. The user interface 12 can be configured to allow physical control, e.g., via a rotary dial, buttons, a keyboard, or a display menu on a touch panel. The user can adjust the vertical position of the STC curve, as well as its inclination, curvature, and the like, by modifying the parameters using the user interface 12.

[0059] As soon as the user changes the parameters of the STC curve by operating the user interface, the changed parameters are immediately reflected in the STC curve setting module 14, and the signal processor 9 then executes the STC procedure based on the changed STC curve. Consequently, as soon as the user changes the parameters of the STC curve, the radar image displayed in the PPI-Scope display area 20 is updated based on the radar image of the changed STC curve. Since the user's setting of the STC curve is reflected in the PPI-Scope display area 20 as described above, the user can adjust the STC curve while looking at the PPI-Scope display area 20.

[0060] The following is a description of the characteristics of this embodiment.

[0061] As in Fig. As shown in Figure 3, the screen of the display unit 16, according to this embodiment, simultaneously displays an A-scope display area 21 alongside the PPI-scope display area 20. The A-scope display area 21 represents a radar image in which the received data from the A-scope is displayed. Consequently, the user can compare the A-scope screen with the PPI-scope screen.

[0062] The characteristics of this embodiment are described in detail below. The receiver of the radar device 1 according to this embodiment comprises an A-scope generator 11. The A-scope generator 11 reads the received data (sweep data) stored in the sampling memory 8 and generates an A-scope radar image that represents the relationship between the signal level of the received data and the distance R to the antenna. The A-scope radar image generated by the A-scope generator 11 is output to the display output unit 13.

[0063] Display output unit 13 outputs the PPI-Scope radar image, input from PPI-Scope generator 10, and the A-Scope radar image, input from A-Scope generator 11, to display unit 16. Display unit 16 shows the PPI-Scope radar image in PPI-Scope display area 20 and the A-Scope radar image in A-Scope display area 21. As described above, PPI-Scope display area 20 is displayed simultaneously side-by-side with A-Scope display area 21.

[0064] In the configuration mentioned above, the PPI-Scope radar image can be displayed simultaneously side by side with the A-Scope radar image on display unit 16.

[0065] Since the sample memory is located upstream of the signal processor 9, the received data (sweep data) stored in the sample memory 8 correspond to the received data before STC processing by the signal processor 9. Consequently, the radar image generated by the A-scope generator 11 displays the received data in the A-scope before STC processing by the signal processor 9.

[0066] Consequently, the received data before signal processing by signal processor 9 (sweep data) can be displayed in the A-scope display area 21 as the A-scope radar image. Conversely, as previously described, the PPI-scope radar image is displayed in the PPI-scope display area 21 based on the data after signal processing generated by signal processor 9 (processed data).

[0067] Consequently, by viewing the screen of the display unit 16, the user can compare the received data before STC processing by the signal processor 9 (A-Scope) with the received data after STC processing (PPI-Scope).

[0068] As previously described, the user can adjust the STC curve in the radar device according to this embodiment by operating the user interface. The user interface can be operated in a state where the PPI scope display area 20 and the A-scope display area 21 are shown on the screen of the display unit 16. Consequently, the user can adjust the STC curve by visually comparing the PPI scope with the A-scope.

[0069] On the other hand, in a conventional radar (e.g., JP H09-72958 A), the STC curve is adjusted after STC processing (PPI scope, processed data), but not the received data before STC processing (A scope, sweep data). Consequently, the STC curve cannot be directly adjusted unless the sweep data is available.

[0070] In the radar device according to this embodiment, the sweep data (A-scope), which represents the processing target in the STC processing, can be compared with the processed data (PPI-scope), which represents the processing result in the STC processing. As a result, it can be easily determined whether the STC curve is appropriately chosen and, consequently, the STC curve can be adjusted more directly compared to conventional methods.

[0071] It is noted that, according to this embodiment, the A-Scope generator 11 generates the A-Scope radar image, displaying all received data from the last sweep. In other words, the received data for the entire range in the distance direction is displayed in the A-Scope display area 21 according to this embodiment. The user can clearly verify the received data for a sweep with a single glance at the A-Scope display area 21. As a result, the STC curve can be set efficiently.

[0072] In many radar devices using an A-scope radar image, the signals received by the antenna are now displayed in real time. However, when, as in the present embodiment of a radar device 1, the antenna 2 rotates in a predetermined cycle and the signals received by the antenna 2 are displayed in the A-scope in real time, the direction Θ in which the signal is displayed in the A-scope changes over time. Consequently, it becomes difficult to compare the A-scope display with the PPI-scope display.

[0073] Consequently, in radar device 1 according to this embodiment, instead of displaying the received data in real time in the A-scope, only the received data in the specific direction Θ is extracted and displayed in the A-scope. Hereinafter, the direction Θ in which the signal is displayed in the A-scope is referred to as the A-scope display direction.

[0074] In the radar device 1 according to this embodiment, an azimuth bearing line 22 (EBL: Electronic Bearing Line) is displayed on the radar image display in the PPI-Scope display area 20. The azimuth bearing line 22 is a solid line on the PPI-Scope radar image with a central origin coordinate (position of the antenna 2) to indicate the A-Scope display direction. The A-Scope display direction in the PPI-Scope can be determined using the azimuth bearing line.

[0075] The direction determined by the azimuth indication line 22 (A-scope display direction) can be conveniently changed using the user interface 12. Consequently, the user can directly determine the desired A-scope display direction while looking at the azimuth indication line 22, which is displayed on the PPI-scope display area 20.

[0076] When antenna 2 points in the A-Scope display direction, which is determined by the azimuth indication line 22, the A-Scope generator 11 reads out the received data (sweep data) for the last sweep stored in the sweep memory 8. Consequently, the A-Scope generator 11 generates the radar image by displaying the received data in the A-Scope.

[0077] As described above, the received data is displayed in the A-Scope display direction, which is determined by the user, in A-Scope display area 21. By displaying the received data in the specific direction in the A-Scope, the user can determine the validity of the STC process by comparing the A-Scope display with the PPI-Scope display.

[0078] As in the case of Fig. 3. It can be observed that the received data displayed in A-Scope display area 21 (Sweep Data) exhibits three peaks. From this, it can be concluded that three target objects exist in the A-Scope display direction and that the reflected signals were received from these three target objects. The reflected signals from the three target objects are then analyzed. Fig. 3 is designated as the first target echo 31, the second target echo 32 and the third target echo 33 in a sequence, starting from a closer distance to the antenna 2.

[0079] On the other hand, if you select the PPI scope display range of 20... Fig. 3. Consider the three echo images on the azimuth indication line 22, which marks the A-scope indication direction. Consequently, the three echo images in the PPI scope can be considered as corresponding to the first target object, echo 31, the second target object, echo 32, and the third target object, echo 33, in that order, starting from a distance closer to the central coordinate (the position of antenna 2). In this case, it can be concluded that the reflection signals from the three target objects were retained even after the STC method. From this, it can be concluded that the STC curve was appropriately set.

[0080] On the other hand, the case of Fig. 2. In the PPI scope display area 20, only two echo images are displayed on the azimuth indication line 22, which indicates the A-scope display direction, although the received data shows three peaks in the A-scope display area 21. More precisely, this means that although the echo images corresponding to the first and second target echoes 31 and 32 are displayed on the azimuth indication line 22 in the PPI scope display area 20, Fig. Since echo 4 is displayed, the third target object echo is not shown. In this case, it can be concluded that the third target object, echo 33, was eliminated by the STC process. From this, it can in turn be concluded that the STC curve was not set appropriately.

[0081] Furthermore, in the example of Fig. 5. A multitude (three or more) of echo images on the azimuth indication line 22, which indicates the A-scope display direction, are displayed in the PPI-scope display area 20, although only three peaks of received data are displayed in the A-scope display area 21. In this case, it can be concluded that unnecessary signal elements are present, such as noise and interference signals, which have not been adequately removed. From this, it can then be concluded that the STC curve was not properly adjusted.

[0082] As described above, the receiver 4, which is provided in the radar device 1 according to this embodiment, comprises the preprocessor 6, the signal processor 9, the PPI scope generator 10, the A scope generator 11, and the display output unit 13. The preprocessor 6 acquires the received signal, which is received by the rotating antenna 2 in a predetermined cycle in the RO coordinate system. The signal processor 9 processes the received signal in the RO coordinate system, depending on its distance, and outputs the processed signals in the RO coordinate system. The PPI scope generator 10 converts the processed signals from the RO coordinate system to the XY orthogonal coordinate system to generate the PPI scope radar image. The A-Scope generator 11 creates the radar image by displaying the received signals in the A-Scope before signal processing by the signal processor 9.The display output unit 13 causes the display unit 16 to display the PPI scope radar image and the A scope radar image simultaneously.

[0083] The following describes a method for displaying a radar received signal by the receiver 4 of the radar device 1 according to this embodiment. In particular, the radar received signal display method includes instructing the preprocessor 6 to acquire the received data originating from the antenna rotating in a predetermined cycle (in the RO coordinate system). The radar received signal display method further includes instructing the signal processor 9 to perform signal processing on the received signal in the RO coordinate system as a function of its distance and to output the processed signal in the RI coordinate system. The radar received signal display method further includes instructing the PPI scope generator 10 to convert the processed signals from the RO coordinate system to the XY orthogonal coordinate system in order to generate the PPI scope radar image.The radar reception signal display procedure further comprises causing the A-Scope generator 11 to display the radar image in which the received data are shown in the A-Scope before signal processing by the signal processor 9. The received signal processing procedure further comprises causing the display output unit 13 to cause the display unit 16 to display the PPI-Scope radar image and the A-Scope radar image simultaneously.

[0084] By simultaneously displaying the A-scope, based on the non-STC-processing received signals, and the PPI-scope, based on the STC-processing received signal as described above, the situation before and after the STC procedure can be compared. Consequently, it can be easily determined whether the STC process was performed correctly.

[0085] The following is a description that specifies further characteristics of the radar device 1 according to this embodiment.

[0086] In the radar device 1 according to this embodiment as in the Fig. As shown in figures 3 to 5, the STC curve 23 is represented by superimposing it onto the received data on the A-Scope.

[0087] Further characteristics are described below. The A-Scope generator 11 receives information regarding the STC curve from the STC curve setting module 14. The A-Scope generator 11 produces the STC curve 223 as an image based on the information input into the STC curve setting module 14. Furthermore, the A-Scope generator 11 generates the radar image in which the image of the STC curve 23 is superimposed on the received data displayed on the A-Scope. Because the image of the STC curve 23 is superimposed on the received data displayed on the A-Scope, the A-Scope generator 11 aligns the vertical and horizontal axes of the STC curve 23 with the vertical and horizontal axes of the received data displayed on the A-Scope. Consequently, the radar image generated by the A-Scope generator 11 is displayed in the A-Scope display area 21 of the display unit 16, as described above.

[0088] According to the aforementioned configuration, by viewing the A-scope display area 21, the user can visually check the STC curve 23 and, furthermore, determine the relationship between the STC curve 23 and the received data. Consequently, the user can ascertain whether the STC curve 23 is appropriately adjusted with regard to the received data.

[0089] For example, by looking at the A-Scope display area 21 of the Fig. 4. The user can easily see that among the three target echoes 31, 32, and 33, the STC curve 23 is excessively increased with respect to the third target echo 33.

[0090] Furthermore, the user can, for example, view the A-Scope display area 21 of Fig. 5 simply recognize that the STC curve 23 is excessively low compared to the level of unnecessary signal elements (noise and interference) in the received data.

[0091] As described above, according to this embodiment, the user can easily determine how to adjust the STC curve 23 by viewing the display in the A-scope display area 21. Consequently, the user can easily adjust the parameters of the STC curve 23 by operating the user interface 12 while viewing the display in the A-scope display area 21.

[0092] As soon as the user activates the user interface 12 to change the parameters of the STC curve 23, the A-Scope generator 11, according to this embodiment, generates the radar image that reflects the changes made. Consequently, the change is immediately displayed in the A-Scope display area 21 as soon as the user operates the user interface 12 to change the parameters of the STC curve 23. Specifically, the change is immediately displayed in the A-Scope display area 21 when the parameters of the STC curve 23 are changed as a result of activation of the user interface 12. In other words, as soon as the parameters are changed by activation of the user interface 12, the vertical position, inclination, curvature, and the like of the STC curve 23 displayed in the display area 21 change.

[0093] Consequently, by adjusting the parameters of the STC curve 23, the user can observe changes in the vertical position, inclination, curvature, and other characteristics of the STC curve 23 as a result in real time within the A-Scope display area 21. In this way, the parameters can be easily adjusted so that the STC curve 23 exhibits the desired characteristics.

[0094] Furthermore, in the A-scope display area 21 according to this embodiment, as in the Fig. Figures 3 to 5 show that the display mode for received data above STC curve 23 (the received data where the signal level exceeds the threshold curve) and the received data below STC curve (the received data where the signal level is not above the threshold) can be set differently. This allows, as in the examples of... Fig. 3 to 5 The data above the STC curve is colored with a specific color. In this way, the user can easily determine, by simply viewing the display of the A-Scope display area 21, the proportion of received data where the signal levels exceed the threshold curve before the STC procedure.

[0095] To achieve such a display, the A-Scope Generator 11, according to this embodiment, includes a threshold determination module 17. The threshold determination module 17 determines whether the signal level of the received data exceeds the threshold curve set by the STC curve. The A-Scope Generator 11 generates the radar image such that the display mode differs for the received data that exceeds the signal level of the threshold curve and the received data that lies below the threshold curve, based on the determination result of the threshold determination module 17.

[0096] The following describes a modification of the first embodiment with reference to Fig. 6.

[0097] The A-Scope Generator 11 of the first embodiment is configured to generate a radar image such that the display mode for the received data differs between the portion above the STC curve 23 and the portion below the STC curve 23. In the present modification, this configuration has been further developed, and the portions of the received data above the STC curve 23 (the portions where the signal level of the received data is above the threshold curve), which contain the reflection signal elements from different target objects, are displayed in different display modes relative to each other.

[0098] Determining whether the received data originate from different target objects, corresponding to the reflection signal elements, can be based on whether the peaks of the signal levels from the parts above STC curve 23 have been separated from each other. In the example of Fig. 6. From the parts above the STC curve 23, provided that the peaks of the first, second and third target objects of echoes 31, 32 and 33 were separated from each other (not continuous with each other), it can be inferred that these parts characterize the reflection signal elements of different target objects.

[0099] In such a case, after this modification, the A-Scope Generator 11 produces the radar image in which the display modes for the parts above the STC curve 23 are different, corresponding to the target objects 31, 32, and 33. For example, after this modification, the A-Scope Generator 1 produces the radar image in which the peaks above the STC curve 23 are colored differently, corresponding to the target object echoes 31, 32, and 33. It is in Fig. 6. Note that the different colors of the peaks of the target object echoes 31, 32 and 33 can also be expressed by different patterns.

[0100] The following section examines the effect of coloring the peaks of the parts above the STC curve with different colors.

[0101] If the peaks representing the reflection signal elements of two or more targets continuously overlap with their portion above STC curve 23, the echo images of the two or more targets will appear merged once the PPI-Scope radar image is generated. In this case, the echo images of the two or more targets will appear as if they originated from a single target. Consequently, it is preferable to adjust STC curve 23 so that the corresponding peaks are appropriately separated.

[0102] In this way, after this modification, once the peaks run independently of each other (not continuously with others) above the STC curve and are displayed in different colors, it can be easily recognized that adjacent peaks displayed in the same color have not been adequately separated. Consequently, it becomes easy to adjust the STC curve 23 so that the corresponding peaks are adequately separated.

[0103] In this modification, the display modes of the corresponding parts between the receiving signal elements of the received signals displayed in the A-Scope, where the signals above the thresholds and the echo images of the PPI-Scope radar images are appropriately matched.

[0104] Thus, with the radar device 1 according to the modification of this embodiment, as e.g. in Fig. Figure 6 shows the three peaks 31, 32, and 33, which exist independently of each other (not continuously with the others) above the STC curve 23 in the A-scope display area 21, corresponding to the colored peaks 31, 32, and 33 with the displayed colors of the three echo images 31, 32, and 33 on the azimuth indication line 22 in the PPI-scope display area 20. It should be noted that in Fig. 6. The differently displayed colors of the echo images are expressed by means of different patterns through hatching of the echo images in the PPI-Scope display area 20.

[0105] Consequently, the relationship between the peaks of the received data in the A-Scope display area 21 and the echo images displayed in the PPI-Scope display area 20 can be easily determined, and the setting of the STC curve 23 becomes significantly easier.

[0106] A second embodiment of the present invention is described below. It should be noted that the following description uses configurations identical or similar to those in the first embodiments described in the text and accompanying drawings, and a further description of these configurations has been omitted.

[0107] In the first embodiment, the parameters of the STC curve 23 can be adjusted by setting the user interface 12; however, if the parameters of the STC curve 23 have to be set each time depending on the situation, this process becomes cumbersome for the user.

[0108] Therefore, in the radar device according to the second embodiment, a plurality of STC curves, in which the parameter settings are different from each other, are preset in the STC curve setting module 14.

[0109] In the radar device according to the second embodiment, the user can select one of the many preset STC curves by operating the user interface 12. The signal processor 9 performs the STC processing by using the selected STC curve.

[0110] By pre-configuring the multitude of STC curves, as described above, the user can select the desired STC curve from among the many pre-defined curves. Consequently, the STC curve can be configured more easily compared to situations where the STC curve parameters have to be changed each time.

[0111] Furthermore, in the radar device of the second embodiment, the A-Scope generator produces the radar image by superimposing the multitude of preset STC curves onto the received data displayed in the A-Scope. The situation in which the radar image was generated as described above is shown in Fig. 7 shown.

[0112] For example, in the A-Scope display area 21, after Fig. 7. A first STC curve 23a, a second STC curve 23b, and a third STC curve 23c are displayed in the A-Scope in a top-to-bottom order by superimposing them onto the received data. By displaying the multitude of preset STC curves by superimposing them onto the received data, which are shown in the A-Scope as described above, the user can instinctively detect and select the desired STC curve.

[0113] Furthermore, the A-Scope generator 11 in the radar device of the second embodiment sets different display modes for the currently selected STC curve and the other or several unselected STC curves. Thus, as in the example according to Fig. 7. The currently selected STC curve is represented by a thick line, and the one or more unselected STC curves are represented as thin, two-dot-dash lines; or in other words, the line types of the STC curves differ depending on whether they have been selected or not. It should be noted that in the example of Fig. Figure 7 shows the situation where the second STC curve 23b was selected.

[0114] Consequently, the user can easily identify which STC curve has been selected by viewing the A-Scope display area 21. Therefore, it becomes easy to select an optimal STC curve from the multitude of preset STC curves.

[0115] Even if the suitable embodiments and modifications of the present invention are as described above, further modified configurations can be used as follows.

[0116] In the embodiments described above, the A-Scope Generator 11 acquires the received data and generates the A-Scope radar image when the antenna 2 is pointing in the predetermined direction. Since the antenna 2 rotates in a predetermined cycle in the horizontal plane, the A-Scope Generator 11 generates the A-Scope radar image according to the rotation cycle of the antenna 2. Consequently, the radar image displayed in the A-Scope display area 21 is updated according to the rotation cycle of the antenna 2. However, without being limited to this, it can be provided, for example, that the radar image displayed in the A-Scope display area 21 is not updated until the user explicitly initiates this.

[0117] The A-Scope Generator 11 can store received data in all azimuth directions. In this case, as soon as the user determines the A-Scope display direction, the A-Scope Generator 11 can read the received data from memory in the specified direction and generate an A-Scope radar image. Consequently, the received data can be displayed in the A-Scope in the specified direction, regardless of the rotation cycle of the antenna 2.

[0118] In the above-mentioned embodiments, the received data is displayed in the A-Scope in the specified direction. However, this is not limited to that direction. For example, the received data received by antenna 2 can be displayed in the A-Scope in real time. In other words, in this case, the received data can be displayed in the A-Scope display area 21 in the direction in which antenna 2 is currently pointing.

[0119] The received data displayed in the A-Scope is not necessarily limited to data received in the specified direction. For example, the received data in all directions can be averaged for any distance, and the averaged data can be displayed in the A-Scope. By displaying the averaged data in the A-Scope, the overall trend of the received data can be determined.

[0120] Furthermore, the threshold curve is not limited to the STC curve and can represent a relationship between the threshold for gain control of the received data (sweep data) and the distance. Thus, the curve can represent a moving average of the signal levels of the received data elements, displayed as a threshold curve. The user can verify the result if they use the moving average curve as the threshold curve.

[0121] In the previously described embodiment, the PPI-scope display area 20 and the A-scope display area 21 are displayed side by side on a single display screen, although this is not limited to this. The present invention can also be applied such that a radar device comprises a plurality of display units (so-called multi-display radar device). In this case, the PPI-scope display area 20 can be displayed on a different display unit (different display screen) than the A-scope display area 21. In this case, the effects of the present invention can be achieved by displaying both screens—the PPI-scope display area 20 and the A-scope display area 21—in such a way that they can be compared visually.

[0122] The characters used to describe the Fig. Figures 3 to 7 illustrate the example where the PPI scope display area 20 and the A-scope display area 21 are shown horizontally side by side. This is not limited to this arrangement, however, and they can also be arranged vertically side by side or diagonally side by side. Alternatively, the PPI scope display area 20 can also be spaced apart from the A-scope display area 21, as long as a comparison between the PPI scope display area 20 and the A-scope display area 21 is not obstructed.

[0123] The signal processor 9 according to the above embodiments performs signal processing (STC processing) on ​​the received data by A / D conversion of the received signal; however, it is not limited to this, and the present invention can also be applied with a configuration in which the origin of the signal processing is based on the analog received signal, which represents the signal before A / D conversion. Such a modification is described in Fig.Figure 8 illustrates this. In this case, the A / D converter 7, located downstream of the signal processor 9, converts the analog signals output by the signal processor 9 and outputs this conversion to the sample memory 8. The PPI-Scope Generator reads the processed signal data stored in the sample memory 8 and generates the PPI-Scope radar image. Furthermore, in this configuration, a second A / D converter 18 can be provided separately for the A / D conversion of the analog signals received before signal processing by the signal processor 9. The A-Scope Generator 11 generates the A-Scope radar image based on the data output by the second A / D converter 18 (received data before signal processing by the signal processor 9).It should be noted that, as an alternative to a separately provided A / D converter 7 and a second A / D converter 18, the functions of these can be achieved by a single A / D converter using time sharing.

[0124] The foregoing description details specific embodiments of the present invention. However, a person skilled in the art in this field can make various modifications and changes without departing from the scope of the present invention, as illustrated in the dependent claims. Accordingly, the description and figures are to be considered merely as exemplary embodiments and not as limiting, and all such modifications are to fall within the scope of the present invention. Described benefits, advantages, and technical problems, as well as any element that contributes a benefit, advantage, or to the solution of the problem, or that has been particularly emphasized, are not to be considered critical, necessary, or essential features and are therefore not required in all claims.The invention is defined exclusively by the attached claims, including all amendments made during the pendency of this application, and by all equivalents of the granted claims.

Claims

[1] Radar receiving device (4) comprising: a receiving signal detector (6) for detecting a received signal, in an RO coordinate system, which was received by an antenna (2) rotating in a predetermined cycle; a signal processor (9) for performing signal processing of the received signal according to a distance in the RΘ coordinate system, and outputting the processed signal in the RΘ coordinate system; a PPI-Scope Generator (10) for converting the processed signal from the RO coordinate system to an XY coordinate system and generating a radar image in a PPI-Scope, an A-Scope generator (11) for generating a radar image of the received signal prior to signal processing by the signal processor (9), displayed in an A-Scope; a display output unit (13) for simultaneously displaying the PPI-Scope radar image and the A-Scope radar image on a display unit (16), and a user interface (12) that allows user input, wherein the signal processor (9) performs the signal processing by applying a threshold value to a signal level of the received signal, the threshold value being set according to a distance, and wherein the A-Scope generator (11) generates the radar image by superimposing a threshold curve onto the received signal displayed in the A-Scope, which represents the relationship between the threshold and the distance, wherein the user can adjust or change the threshold curve via the user interface (12) in a state where the threshold curve is displayed on the display unit (16) and wherein the A-Scope Generator (11) generates the radar image, in which the adaptation or modification thereof is represented, wherein the threshold curve contains a plurality of curves, wherein the user interface (12) selects one from the plurality of threshold curves, and wherein the signal processor (9) performs the signal processing by using the threshold curve selected via the user interface (12). [2] The radar receiving device (4) according to claim 1, wherein the A-Scope generator (11) can vary the display mode of the currently selected threshold curve and the other threshold curve. [3] The radar receiving device (4) according to claim 1 or 2, further comprising a threshold determiner (17) to determine whether the signal level of the received signal exceeds the threshold before signal processing by the signal processor (9), wherein, based on the determination result of the threshold determiner (17), the A-Scope Generator (11) generates the radar image by switching a display mode between a receiving signal element of the received signal which has a signal level above the threshold and a receiving signal element of the received signal which has a signal level below the threshold. [4] The radar receiving device (4) according to claim 3, wherein the display mode of a receiving signal element of the received signal, which is displayed in the A-Scope, of which the signal level is above the threshold, is adapted to the display mode of an echo image, which is contained in the PPI-Scope radar image, which corresponds to the receiving signal element. [5] The radar receiving device (4) according to any one of claims 1 to 4, wherein the A-Scope generator (11) generates the radar image in which the received signal is displayed in a predetermined A-Scope display direction in the A-Scope. [6] Radar receiving device (4) according to claim 5, wherein the user interface (12) specifies the A-Scope display direction on the PPI-Scope radar image which is displayed in the display unit (16). [7] A radar device (1) comprising: the radar receiving device (4) according to any one of claims 1 to 6, the antenna (2), and a transmitter to generate a transmission signal at the antenna (2). [8] A method for displaying a radar reception signal comprising: Capturing a received signal in an RO coordinate system, which was received by an antenna (2) rotating in a predetermined cycle, Performing signal processing of the received signal according to a distance in the RO coordinate system and outputting the processed signal in the RO coordinate system, wherein a signal processor (9) performs the signal processing by applying a threshold value to the signal level of the received signal, the threshold value being set according to a distance, and Converting the processed signal from the RO coordinate system to an XY orthogonal coordinate system and generating a radar image in a PPI scope, Generating a radar image where the received signal is displayed in an A-scope before signal processing is performed, Simultaneous display of the PPI-Scope radar image and the A-Scope radar image, and acceptance of user input, wherein an A-Scope generator (11) generates the radar image by superimposing a threshold curve onto the received signal displayed in the A-Scope, which represents the relationship between the threshold and the distance, wherein by means of a user interface (12) the user can adjust or change the threshold curve in a state where the threshold curve is displayed on the display unit (16) and wherein the A-Scope Generator (11) generates the radar image, in which the adaptation or modification thereof is represented, wherein the threshold curve contains a plurality of curves, wherein the user interface (12) selects one from the plurality of threshold curves, and wherein the signal processor (9) performs the signal processing by using the threshold curve selected via the user interface (12). [9] The method for displaying a radar received signal according to claim 8, wherein the execution of the signal processing comprises performing the signal processing in which a threshold is applied to a signal level of the received signal, wherein the threshold is set according to the distance, and wherein the generation of the radar image in the A-Scope comprises generating the radar image by superimposing a threshold curve, which represents a ratio between the threshold and the distance, and the received signal, which was displayed in the A-Scope.

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