JP5134850B2 - Beam scanning apparatus and beam scanning method - Google Patents

Description

  The present invention relates to a beam scanning apparatus and a beam scanning method for leveling a directivity gain in the vicinity of a beam directing direction in a system that inputs and outputs energy using a beam having a non-uniform directivity gain.

  Conventionally, various systems for inputting, outputting, and inputting / outputting energy using a beam having a non-uniform directional gain are known. Here, as an example, a conventional beam scanning apparatus in a three-dimensional radar apparatus will be described. FIG. 11 is a block diagram showing a configuration of a radar apparatus having a conventional beam scanning apparatus. As shown in FIG. 11, the conventional radar apparatus includes an antenna 1, a circulator 2, a transmitter 3, a receiver 4, a signal processing unit 5, a scanning angle control unit 6, and a radar control unit 7. Further, the radar control unit 7 includes a beam scanning angle selector 11a and a beam scanning angle table 12a. Here, the conventional beam scanning apparatus includes a scanning angle control unit 6 and a radar control unit 7.

  The transmitter 3 generates a transmission signal and outputs it to the circulator 2. The circulator 2 has three ports and transmits power only in a specific direction. Here, the circulator 2 outputs the transmission signal input by the transmitter 3 to the antenna 1.

  The radar control unit 7 generates a beam scanning angle signal based on the beam scanning angle and outputs it to the scanning angle control unit 6. Details of generation of the beam scanning angle signal by the radar controller 7 will be described later.

  The scanning angle control unit 6 generates an antenna control signal that indicates the beam pointing direction of the antenna 1 based on the beam scanning angle signal input by the radar control unit 7. Thereafter, the scanning angle control unit 6 outputs the generated antenna control signal to the antenna 1.

  The antenna 1 converts the transmission signal input by the circulator 2 into a radio wave to generate a transmission wave, and transmits it toward a space in a predetermined direction based on the antenna control signal input by the scanning angle control unit 6. The antenna 1 receives the reflected wave of the transmission wave, converts it into an electrical signal, and outputs it to the circulator 2. The circulator 2 outputs the input electrical signal to the receiver 4.

  The receiver 4 performs frequency conversion of the electrical signal input by the antenna 1 via the circulator 2. Further, the receiver 4 outputs a received signal obtained by frequency-converting the electrical signal to the signal processing unit 5.

  The signal processing unit 5 detects a target based on the received signal input by the receiver 4. The detected target is output to, for example, a display (not shown) or a tracking device that performs tracking processing.

  Next, the operation of the conventional beam scanning apparatus configured as described above will be described. In the radar control unit 7, the beam scanning angle table 12a stores a plurality of beam position numbers and beam scanning angles corresponding to the plurality of beam position numbers.

The beam scanning angle selector 11a updates the beam position number and outputs a beam scanning angle signal corresponding to the beam scanning angle corresponding to the beam position number to the scanning angle control unit 6 with reference to the beam scanning angle table 12a. . Here, the n-th beam position number i (n) is given by the following equation.

Here, i _min is the minimum value of the beam position number. I _max is the maximum value of the beam position number. FIG. 12 shows the contents stored in the beam scanning angle table 12a. As shown in FIG. 12, for example, when the minimum value and the maximum value of the beam position number are 1 and 9, respectively, the beam position number is sequentially updated from the minimum value of 1 until reaching the maximum value of 9. Based on the equation (2), the beam position number returns to the minimum value 1 when the maximum value 9 is reached, and thus changes as {1, 2, 3,..., 9, 1, 2, 3,.

  The scanning angle control unit 6 converts the beam scanning angle based on the beam scanning angle signal input by the radar control unit 7 into an antenna control signal corresponding to the beam scanning angle of the antenna 1 and outputs the antenna control signal to the antenna 1.

The antenna 1 forms a directional beam centered on the beam scanning angle corresponding to the beam position number selected by the beam scanning angle selector 11 a based on the antenna control signal input by the scanning angle control unit 6. Here, as an example, the beam directivity gain is given by the following equation.

  Here, G is the directivity gain of the beam. X is the value of the X axis. Y is a value of the Y axis. X0 is the beam center value on the X axis. Y0 is the beam center value on the Y axis.

  Further, it is assumed that the beam scanning angle table 12a stores the beam position number and the beam scanning angle having the contents shown in FIG. FIG. 13 shows a state of beam scanning processing by a conventional radar apparatus.

  First, FIG. 13 (a) shows a beam scanning situation, in which an outline of a beam having a predetermined gain or more on the xy plane is drawn. In FIG. 13A, nine circles are drawn on the xy plane, and the center point of each circle corresponds to the nine beam scanning angles shown in FIG.

  FIG. 13B is a diagram showing the directivity gain when a series of beam scans are completed, and shows the directivity gain of the beam shown by the expression (3) with respect to xy in a three-dimensional manner. is there. That is, FIG. 13B can be considered to indicate the beam intensity on a certain plane (xy plane) on which the beam is projected. FIG. 13B shows that the gain at the center of the beam is high and the gain at the position between the beams is low.

FIG. 13C is a diagram showing detection probabilities when a series of beam scans are completed. Here, it is assumed that the target detection probability is given by the following equation.

  Here, Pd is a detection probability. Pfa is a false alarm probability. Furthermore, SNR is the signal to noise ratio. As shown in FIG. 13C, the detection probability shows the same unevenness due to the influence of the directivity gain unevenness.

Patent Document 1 describes a radar antenna system that can lower the correlation between a plurality of adjacent radar beams and reduce deterioration in detection performance in the vicinity of the intersection direction of the directional pattern. According to this radar aerial system, the polarization switching of each scanning beam output from the beam scanning circuit is switched for each scanning beam and given to the aerial aperture as each scanning beam having a different polarization characteristic. Since the circuit is provided, the polarization characteristics between a plurality of adjacent radar beams can be made different. Therefore, this polarization switching circuit changes the propagation characteristics of the radio waves and the reflection characteristics from the target, obtains the diversity effect, reduces the correlation between the radar beams, and degrades the detection performance near the direction of the intersection of the pointing patterns. Therefore, the detection probability of the overlapping portion of the radar beam is increased, and the detection performance is improved.
JP-A-6-230109

  However, since the conventional beam scanning apparatus described above fixes the beam scanning angle for each beam position number, the beam directing direction for each beam position number does not change. As a result, the difference in directivity gain (high in a position close to the beam directing direction and low in a distant place) is fixed, so that a fixed difference also occurs in performance depending on gain, for example, detection probability. For this reason, in order to achieve the specified detection performance even at the lowest gain (worst case), it is necessary to increase the transmission power of the transmitter and the antenna gain of the antenna. Will grow.

  The above situation also applies to the case where the radar antenna system described in Patent Document 1 is used. In this radar antenna system, each scanning beam output from the beam scanning circuit is biased for each scanning beam in order to reduce the correlation between the radar beams and to reduce the deterioration of the detection performance in the vicinity of the intersection direction of the directivity pattern. Since it has a polarization switching circuit that switches the wave characteristics and gives each scanning beam with different polarization characteristics to the aerial aperture, the scale of the entire device is expanded, and power is also required for polarization switching .

  The present invention solves the above-described problems of the prior art. A beam scanning apparatus and a beam that can improve the detection performance by reducing the variation in directivity gain without increasing the scale of the apparatus with a simple configuration. It is an object to provide a scanning method.

In order to solve the above problems, a beam scanning apparatus according to the present invention is a beam scanning apparatus that controls a beam having a non-uniform directivity gain, and has a plurality of predetermined beam scanning angles. A beam scanning angle selection unit that generates a first beam scanning angle signal corresponding to the selected beam scanning angle, a noise generation unit that generates noise, and the plurality of predetermined beams A noise addition range based on a scanning angle is set, and a random number obtained by subjecting the noise generated by the noise generation unit to at least one of translation or scaling according to the noise addition range is used as the beam scanning. A second beam scanning angle signal corresponding to the beam scanning angle obtained by adding the beam scanning angle corresponding to the first beam scanning angle signal generated by the angle selector is generated. To with a noise adding section for updating the random number to be added at a predetermined time, the scanning angle to produce an antenna control signal for instructing the beam pointing direction of the antenna based on the second beam scanning angle signal generated by the noise adding unit And a control unit.

A second invention is a beam scanning device for controlling a beam having a non-uniform directivity gain, sequentially selecting one of a plurality of predetermined beam scanning angles, and at the selected beam scanning angle. A beam scanning angle selection unit that generates a first beam scanning angle signal in response, a noise generation unit that generates noise, a noise addition range based on the plurality of predetermined beam scanning angles, and the noise generation unit An overrange processing unit for selecting only a random number within a predetermined range from random numbers obtained by subjecting the generated noise to at least one of parallel movement or scaling according to the noise addition range; and the beam scanning angle. It is obtained by adding the random number selected by the overrange processing unit to the beam scanning angle corresponding to the first beam scanning angle signal generated by the selection unit. And to generate a second beam scan angle signal corresponding to the beam scan angle, based on the noise adding section for updating the random number to be added at a predetermined time, the second beam scanning angle signal generated by the noise adding unit antenna And a scanning angle control unit for generating an antenna control signal for instructing the beam directing direction.

A third invention is a beam scanning device for controlling a beam having a non-uniform directivity gain, sequentially selecting one of a plurality of predetermined beam scanning angles, and at the selected beam scanning angle. A beam scanning angle selection unit that generates a first beam scanning angle signal corresponding to the first beam scanning angle signal, and a random number pattern set in advance for the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selection unit. Generating a second beam scanning angle signal corresponding to the beam scanning angle obtained by adding the random numbers based on the noise, and updating a random number to be added at a predetermined time; and a second noise generating unit generated by the noise adding unit. And a scanning angle control unit that generates an antenna control signal that indicates the beam directing direction of the antenna based on the two-beam scanning angle signal.

  According to the first aspect of the present invention, random numbers based on noise are added to the beam directing direction without increasing the scale of the apparatus with a simple configuration, and variation in directivity gain is reduced to improve detection performance. Can do.

  According to the second aspect of the present invention, detection is performed by adding only a random number having a size within a predetermined range in the beam directing direction and reducing variation in directivity gain without increasing the scale of the apparatus with a simple configuration. The performance can be improved.

  According to the third aspect of the present invention, a random number based on a random number pattern preset in the beam directing direction is added in the beam directing direction without increasing the scale of the apparatus with a simple configuration, thereby reducing the variation in directivity gain. The performance can be improved.

  Embodiments of a beam scanning apparatus according to the present invention will be described below in detail with reference to the drawings.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram illustrating a configuration of a radar apparatus having a beam scanning apparatus according to a first embodiment of the present invention. In FIG. 1 and the drawings showing the respective embodiments described later, the same or equivalent components as those in FIG. 11 described as the background art are denoted by the same reference numerals as those described above, and redundant description is omitted. As shown in FIG. 1, the radar apparatus includes an antenna 1, a circulator 2, a transmitter 3, a receiver 4, a signal processing unit 5, a scanning angle control unit 6, and a radar control unit 7. Further, the radar controller 7 includes a beam scanning angle selector 11b, a beam scanning angle table 12b, a noise adder 13, and a noise generator 14. Here, the beam scanning apparatus according to the present embodiment is a beam scanning apparatus that controls a beam having a non-uniform directivity gain that is input and output from the antenna 1, and includes a scanning angle control unit 6 and a radar control unit. 7.

  The beam scanning angle selector 11b corresponds to the beam scanning angle selection unit of the present invention, and sequentially selects one of a plurality of predetermined beam scanning angles, and the first beam scanning corresponding to the selected beam scanning angle. An angular signal is generated. Specifically, the beam scanning angle selector 11b updates the beam position number and generates a first beam scanning angle signal corresponding to the beam scanning angle corresponding to the beam position number with reference to the beam scanning angle table 12b. And output to the noise adder 13.

  The beam scanning angle table 12b stores a plurality of beam position numbers and beam scanning angles corresponding to the plurality of beam position numbers. In the present embodiment, the beam scanning angle table 12b stores the beam position number and the beam scanning angle shown in FIG. 12, similarly to the beam scanning angle table 12a described as the prior art.

  The noise generator 14 corresponds to the noise generator of the present invention and generates noise. Specifically, the noise generator 14 generates noise based on any one of a quasi-random number, a pseudo-random number, and a physical random number.

  FIG. 2 is a diagram illustrating the output of the noise generator 14. FIG. 2A shows the output of the quasi-random number generator using the Faure sequence. The quasi-random number is characterized in that each point is determined according to a function, and a more uniform distribution than the pseudo-random number can be obtained. Further, since the quasi-random numbers are uniformly distributed in the multidimensional space, as shown in FIG. 2A, it is possible to obtain a distribution in which each point does not overlap.

  FIG. 2B is a diagram showing the output of the pseudorandom number generator using the Mersenne Twister method. Since the pseudo-random numbers for each of the x-axis and the y-axis are obtained independently, there are some overlapping points.

  FIG. 2C shows the output of the physical random number generator. The physical random number is generated by using a physical phenomenon by hardware. For example, a method using thermal noise generated at a PN junction of a diode is often used. Also in this case, since the physical random numbers of the x-axis and the y-axis are obtained independently, there are some overlapping points.

  The noise adder 13 corresponds to the noise adding unit of the present invention, sets a noise adding range based on a plurality of predetermined beam scanning angles, and adjusts the noise generated by the noise generator 14 to the noise adding range. Beam scanning obtained by adding a random number obtained by performing at least one of translation or scaling to a beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11b. A second beam scanning angle signal corresponding to the angle is generated. The setting of noise addition range, parallel movement, and scaling will be described later.

  The scanning angle control unit 6 generates an antenna control signal that indicates the beam pointing direction of the antenna 1 based on the second beam scanning angle signal generated by the noise adder 13. Thereafter, the scanning angle control unit 6 outputs the generated antenna control signal to the antenna 1.

  The antenna 1 converts the transmission signal input by the circulator 2 into a radio wave to generate a transmission wave, and transmits it toward a space in a predetermined direction based on the antenna control signal input by the scanning angle control unit 6. The antenna 1 receives the reflected wave of the transmission wave, converts it into an electrical signal, and outputs it to the circulator 2. The circulator 2 outputs the input electrical signal to the receiver 4.

  Other configurations are the same as those of the conventional radar apparatus described with reference to FIG.

  Next, the operation of the beam scanning apparatus of the present embodiment configured as described above will be described. First, the beam scanning angle selector 11b in the radar control unit 7 sequentially selects one of a plurality of predetermined beam scanning angles as described above. Specifically, the beam scanning angle selector 11b updates the beam position number and selects the beam scanning angle corresponding to the beam position number with reference to the beam scanning angle table 12b. In the present embodiment, the beam scanning angle table 12b stores the beam position number and the beam scanning angle shown in FIG. Since the beam position number is given by the equations (1) and (2) as described above, the beam scanning angle selector 11b sets the beam position number to 1, 2, 3,... 9, 1, 2,. Thus, the numbers 1 to 9 are updated so as to be repeated, and the first beam scanning angle signal corresponding to the beam scanning angle corresponding to the beam position number is generated.

  Next, as described above, the noise generator 14 generates noise based on any one of a quasi-random number, a pseudo-random number, and a physical random number. In this embodiment, as shown in FIG. 2, it is assumed that noise is obtained in the range of 0 to 1 for both the X axis and the Y axis by the noise generator 14.

  The noise adder 13 obtains information on a plurality of predetermined beam scanning angles stored in the beam scanning angle table 12b via the beam scanning angle selector 11b, and a noise addition range based on the plurality of predetermined beam scanning angles. Set. The noise addition range is a regular polygon (hereinafter referred to as a filling shape) that can cover the two-dimensional space without any gap, and is a regular triangle as shown in FIGS. 3 (a), 3 (b), and 3 (c). , Square, and regular hexagon. For this reason, the circle corresponding to the beam shape becomes a circumscribed circle of a filling shape as shown in FIGS. 3 (d), 3 (e), and 3 (f). When the beam shape is an ellipse, the noise addition range can be a triangle, a rectangle, or a hexagon that is scaled in the vertical or horizontal direction corresponding to the beam shape. Here, FIG. 4 shows a noise addition range in the beam scanning apparatus of the embodiment. The drawn nine circles are the contour lines of the beam having a predetermined gain or more on the xy plane, as in FIG. Since the beam position in FIG. 4 corresponds to FIG. 3 (e), the noise addition range (filled shape) is a quadrangle as shown in FIG. 3 (b). The noise adder 13 sets a square having a vertex at a point where the center circle intersects with another circle as the noise addition range. Further, the noise addition range is not necessarily a quadrangle. Any setting method of the noise addition range by the noise adder 13 may be used, and the noise addition range that can reduce variation in the directivity gain of the beam is calculated. The noise adder 13 determines a random number indicating the amount of change that changes the beam directing direction within the noise addition range.

  Next, the noise adder 13 performs at least one of translation or scaling on the noise generated by the noise generator 14 in accordance with the noise addition range to obtain a random number. In this embodiment, both translation and scaling are performed. Specifically, from FIG. 4, the beam width is 1, and the range of noise to be added is a quadrilateral inscribed in a circle centered on the origin. Therefore, the noise addition ranges are −√2 / 4 ≦ X ≦ √2 / 4 and −√2 / 4 ≦ Y ≦ √2 / 4. The output of the noise generator 14 is 0 ≦ X ≦ 1 and 0 ≦ Y ≦ 1, as shown in FIG. Therefore, first, the noise adder 13 performs parallel movement by adding −½ to the X axis component and the Y axis component of the output of the noise generator 14 respectively. By this parallel movement, the output of the noise generator 14 becomes random numbers distributed in the range of −1 / 2 ≦ X ≦ 1/2 and −1 / 2 ≦ Y ≦ 1/2. Next, the noise adder 13 performs scaling by multiplying the X-axis component and the Y-axis component of the obtained random number by √2 / 2, respectively. By this scaling, random numbers distributed in the ranges of −√2 / 4 ≦ X ≦ √2 / 4 and −√2 / 4 ≦ Y ≦ √2 / 4 are obtained.

  Finally, the noise adder 13 adds the obtained random number to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11b according to the beam scanning angle obtained. The second beam scanning angle signal is generated.

  Specifically, in this embodiment, the beam position numbers are 1 to 9. The beam scanning angle selector 11b updates the beam position number as 1, 2, 3,... 9, 1, 2,. First, while the beam position number changes from 1 to 9, the noise adder 13 adds the X component and the Y component corresponding to any one of the obtained random numbers to the beam scanning angle. Next, when the beam position number returns to 1, the noise adder 13 updates the obtained random number to another random number that is not yet used, and corresponds to the random number until the beam position number is updated to 9. The X component and Y component to be added are added to the beam scanning angle. Next, when the beam position number returns to 1, the noise adder 13 again updates the random number obtained to another random number that has not been used yet, and the random number is updated until the beam position number is updated to 9. The corresponding X and Y components are added to the beam scanning angle. Thus, the noise adder 13 repeats the update of the random number. The noise adder 13 outputs the generated second beam scanning angle signal to the scanning angle control unit 6.

  The scanning angle control unit 6 generates an antenna control signal that indicates the beam pointing direction of the antenna 1 based on the second beam scanning angle signal input by the noise adder 14 in the radar control unit 7. Thereafter, the scanning angle control unit 6 outputs the generated antenna control signal to the antenna 1.

  The antenna 1 transmits toward a space in a predetermined direction based on the antenna control signal input by the scanning angle control unit 6. That is, the antenna 1 forms a directional beam centered on the beam scanning angle corresponding to the first beam scanning angle signal output from the beam scanning angle selector 11b.

  FIG. 5 shows a state of beam scanning processing by a radar apparatus having the beam scanning apparatus of the present embodiment. FIG. 5A shows a result of overlapping beam scanning for 10 times by a beam scanning device using a noise generator 14 that generates noise based on a quasi-random number. Furthermore, FIG. 5B shows the directivity gain when a series of beam scans are completed. FIG. 5C shows the detection probability (average value). By adding a random number within the noise addition range to the beam scanning angle, the unevenness of the directivity gain is reduced and the unevenness of the detection probability is also reduced.

  As described above, according to the beam scanning apparatus according to the first embodiment of the present invention, random numbers based on noise are added to the beam directing direction without increasing the scale of the apparatus with a simple configuration, and variation in directivity gain is achieved. Detection performance can be improved.

  Further, since the noise adder 13 performs at least one of parallel movement and scaling on the noise generated by the noise generator 14, the noise addition range can be set relatively freely.

  Since the unevenness of the directivity gain near the beam directing direction can be reduced, it is necessary to increase the transmission power of the transmitter and the antenna gain of the antenna in order to achieve the specified detection performance at the lowest gain (worst case) The device can be downsized.

  In addition, it is not necessary to provide a polarization switching circuit used in the radar antenna system described in Patent Document 1, and only a random number based on noise is added as a numerical value to the beam scanning angle corresponding to the beam scanning angle signal. This can be realized with a simple configuration.

  Next, a beam scanning apparatus according to the second embodiment will be described. FIG. 6 is a block diagram illustrating a configuration of a radar apparatus having the beam scanning apparatus according to the second embodiment of the present invention. The difference from the configuration of the first embodiment is that an overrange processor 15 is newly provided in the radar control unit 7.

  The overrange processor 15 corresponds to the overrange processor of the present invention, sets a noise addition range based on a plurality of predetermined beam scanning angles, and sets the noise addition range for noise generated by the noise generator 14. In addition, only random numbers within a predetermined range are selected from random numbers obtained by performing at least one of parallel movement and scaling. Details will be described later.

  The noise adder 13c adds the random number selected by the overrange processor 15 to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11c. A second beam scanning angle signal corresponding to the scanning angle is generated.

  The beam scanning angle table 12c stores a plurality of beam position numbers and beam scanning angles corresponding to the plurality of beam position numbers. FIG. 7 shows the contents stored in the beam scanning angle table 12c.

  Other configurations are the same as those of the first embodiment, and a duplicate description is omitted.

  Next, the operation of the beam scanning apparatus of the present embodiment configured as described above will be described. First, the beam scanning angle selector 11c in the radar controller 7 sequentially selects one of a plurality of predetermined beam scanning angles. Specifically, the beam scanning angle selector 11c updates the beam position number and refers to the beam scanning angle table 12c to select the beam scanning angle corresponding to the beam position number. Since the beam position number is given by the equations (1) and (2) as in the first embodiment, the beam scanning angle selector 11c sets the beam position number to 1, 2, 3,. As described above, the numbers 1 to 9 are updated so as to be repeated, and a first beam scanning angle signal corresponding to the beam scanning angle corresponding to the beam position number is generated.

  Next, as in the first embodiment, the noise generator 14 generates noise based on any one of a quasi-random number, a pseudo-random number, and a physical random number. In this embodiment, as shown in FIG. 2, it is assumed that noise is obtained in the range of 0 to 1 for both the X axis and the Y axis by the noise generator 14.

  The overrange processor 15 obtains information on a plurality of predetermined beam scanning angles stored in the beam scanning angle table 12c, and sets a noise addition range based on the plurality of predetermined beam scanning angles. Here, FIG. 8 shows a noise addition range in the beam scanning apparatus of the embodiment. The drawn nine circles are the contour lines of the beam having a predetermined gain or more on the xy plane, as in FIG. Since the beam position in FIG. 8 corresponds to FIG. 3F, the noise addition range (filled shape) is a hexagon as shown in FIG. 3C. Here, when the filling shape is a hexagon, the circular overlap corresponding to the beam shape is the smallest. In the radar apparatus, the small overlap of the beams that cover the two-dimensional space without any gap means that the number of beam positions used for searching the predetermined space can be reduced, and as a result, the time for scanning the predetermined space is shortened. . Alternatively, the performance can be improved by increasing the number of integrated pulses per predetermined space and time (increasing the number of transmission and reception of the same beam position). The overrange processor 15 sets a hexagon having a vertex at a point where the center circle intersects with another circle as the noise addition range. In the case of the first embodiment, as shown in FIG. 4, since the noise addition range is a square, the noise adder 13 matches the noise addition range by translating and scaling the output of the noise generator 14. I was able to. However, in the present embodiment, since the noise addition range is a hexagon, the overrange processor 15 cannot match the output of the noise generator 14 to the noise addition range only by translation and scaling.

  Therefore, the overrange processor 15 only applies random numbers within a predetermined range among random numbers obtained by subjecting the noise generated by the noise generator 14 to at least one of parallel movement and scaling according to the noise addition range. Select. Specifically, the overrange processor 15 first performs both parallel movement and scaling in the same manner as in the first embodiment in order to determine a random number indicating the amount of fluctuation that changes the beam directing direction within this noise addition range. Do. Thereby, the overrange processor 15 obtains random numbers distributed in the ranges of −√2 / 4 ≦ X ≦ √2 / 4 and −√2 / 4 ≦ Y ≦ √2 / 4.

  Next, the overrange processor 15 determines whether or not the obtained random number falls within the hexagon that is the noise addition range, and selects only the random number within the hexagon. Further, when the desired number of random numbers cannot be obtained within the noise addition range, the overrange processor 15 repeats the above-described processing on the output of the noise generator 14 until it is obtained. In this way, the overrange processor 15 generates uniform noise within the noise addition range.

  The noise adder 13c adds the random number selected by the overrange processor 15 to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11c. A second beam scanning angle signal corresponding to the scanning angle is generated.

  More specifically, since the beam position numbers 1 to 9 are the same as in the first embodiment, the beam scanning angle selector 11c sets the beam position numbers 1, 2, 3,... 9, 1, 2,. Update to Similar to the first embodiment, the noise adder 13c updates the random number obtained by the overrange processor 15 to another unused random number every time the beam position number becomes the minimum value, The X and Y components corresponding to the random number are added to the beam scanning angle until the number is updated to 9. The noise adder 13 c outputs the generated second beam scanning angle signal to the scanning angle control unit 6. Subsequent operations are the same as those in the first embodiment, and redundant description is omitted.

  As described above, according to the beam scanning apparatus according to the second embodiment of the present invention, in addition to the effects of the first embodiment, a random number within a predetermined range in the beam directing direction without increasing the apparatus scale with a simple configuration. To improve the detection performance by reducing the variation of the directivity gain.

  In addition, since the overrange processor 15 is provided, even in a noise addition range that is difficult to be matched only by performing parallel movement and scaling with respect to the noise generated by the noise generator 14, noise within the range is uniform. (Random number) can be set.

  Next, a beam scanning apparatus according to Embodiment 3 will be described. FIG. 9 is a block diagram illustrating a configuration of a radar apparatus having the beam scanning apparatus according to the third embodiment of the present invention. The difference from the configuration of the first embodiment is that the radar generator 7 does not have the noise generator 14 used in the first embodiment and has a noise table 16 instead.

  The noise adder 13d is obtained by adding a random number based on a random number pattern preset in the noise table 16 to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11d. A second beam scanning angle signal corresponding to the beam scanning angle is generated.

  Further, the noise table 16 stores a plurality of noise numbers and noise corresponding to each of the plurality of noise numbers. FIG. 10 shows noise numbers and noises stored in the noise table 16 in this embodiment. Note that the noise number and noise random number pattern stored in the noise table 16 are not limited to one, and a pattern used by the operator can be selected according to the purpose. Further, a configuration may be used in which the noise adder 13d automatically selects a pattern to be used instead of the operator.

  Other configurations are the same as those of the first embodiment, and a duplicate description is omitted.

Next, the operation of the beam scanning apparatus of the present embodiment configured as described above will be described. Basically, the operation is the same as that of the beam scanning apparatus according to the first embodiment. The beam scanning angle selector 11d updates the beam position number, selects a beam scanning angle corresponding to the beam position number with reference to the beam scanning angle table 12d, and a first beam scanning angle signal corresponding to the beam scanning angle. The noise adder 13d adds a random number based on a random number pattern preset in the noise table 16 to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11d. A second beam scanning angle signal corresponding to the obtained beam scanning angle is generated. Specifically, the noise adder 13d updates the noise number and refers to the noise table 16 to select the noise corresponding to the noise number. The beam scanning angle selector 11d may update the noise number and output it to the noise adder 13d instead of the noise adder 13d. The nth noise number j (n) is given by the following equation.

Here, j _min is the minimum value of the noise number. J _max is the maximum noise number. i _min is the minimum value of the beam position number as described above. The beam position numbers are given by the equations (1) and (2), and are 1 to 9 in this embodiment. The noise numbers are from 1 to 100 as shown in FIG.

  As in the first and second embodiments, the beam scanning angle selector 11b updates the beam position number as 1, 2, 3,... 9, 1, 2,. Initially, the noise number is 1 while the beam position number changes from 1 to 9. Next, when the beam position number returns to 1, the noise number is updated to 2, and is fixed to 2 until the beam position number is updated to 9. Next, when the beam position number returns to 1, the noise number is updated to 3, and is fixed to 3 until the beam position number is updated to 9. Thus, the noise adder 13d or the beam scanning angle selector 11d repeats the update of the variation number.

  The noise adder 13d corresponds to the noise number with reference to a random number pattern preset in the noise table 16 with respect to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selector 11d. Noise (random number) to be selected is selected and added, a second beam scanning angle signal corresponding to the obtained beam scanning angle is generated, and output to the scanning angle control unit 6.

  Subsequent operations are the same as those in the first embodiment, and redundant description is omitted.

  As described above, according to the beam scanning apparatus according to the third embodiment of the present invention, in addition to the effects of the first embodiment, a random number set in advance in the beam directing direction without increasing the apparatus scale with a simple configuration. A random number based on the pattern can be added to reduce the directivity gain variation and improve the detection performance.

  Further, the noise table 16 can be constituted by a small storage device or the like, and since the noise generator 14 and the overrange processor 15 are not required as in the first and second embodiments, the apparatus can be reduced in size and cost. Can be achieved.

  Further, the noise table 16 stores a plurality of patterns related to a combination of noise number and noise, so that beam scanning can be performed by selecting a pattern flexibly according to the situation.

  The beam scanning device according to the present invention can be used in devices such as radar, laser radar, and sonar.

It is a block diagram which shows the structure of the radar apparatus which has a beam scanning apparatus of the form of Example 1 of this invention. It is a figure which shows the output of the noise generator of the beam scanning apparatus of the form of Example 1 of this invention. It is a figure explaining the noise addition range in a beam scanning apparatus. It is a figure which shows the noise addition range in the beam scanning apparatus of the form of Example 1 of this invention. It is a figure which shows the mode of the beam scanning process by the radar apparatus which has a beam scanning apparatus of the form of Example 1 of this invention. It is a block diagram which shows the structure of the radar apparatus which has the beam scanning apparatus of the form of Example 2 of this invention. It is a figure which shows the content which the beam scanning angle table which the beam scanning apparatus of Example 2 of this invention has has memorize | stores. It is a figure which shows the noise addition range in the beam scanning apparatus of the form of Example 2 of this invention. It is a block diagram which shows the structure of the radar apparatus which has a beam scanning apparatus of the form of Example 3 of this invention. It is a figure which shows the content which the noise table which the beam scanning apparatus of Example 3 of this invention has has is memorize | stored. It is a block diagram which shows the structure of the radar apparatus which has the beam scanning apparatus of the conventional form. It is a figure which shows the content which the beam scanning angle table which the beam scanning apparatus of the conventional form has memorize | stores. It is a figure which shows the mode of the beam scanning process by the radar apparatus which has the beam scanning apparatus of the conventional form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2 Circulator 3 Transmitter 4 Receiver 5 Signal processing part 6 Scan angle control part 7 Radar control part 11a, 11b, 11c, 11d Beam scanning angle selector 12a, 12b, 12c, 12d Beam scanning angle table 13, 13c, 13d Noise adder 14 Noise generator 15 Overrange processor 16 Noise table

Claims (9)

A beam scanning device for controlling a beam having a non-uniform directivity gain,
A beam scanning angle selection unit that sequentially selects one of a plurality of predetermined beam scanning angles and generates a first beam scanning angle signal according to the selected beam scanning angle;
A noise generator that generates noise;
Obtained by setting a noise addition range based on the plurality of predetermined beam scanning angles and performing at least one of parallel movement or scaling on the noise generated by the noise generation unit according to the noise addition range a random number, and generates a second beam scan angle signal corresponding to the beam scanning angle obtained by adding to the beam scan angle corresponding to the first beam scan angle signal generated by the beam scanning angle selector A noise adding unit that updates a random number to be added at a predetermined time ;
A scanning angle control unit that generates an antenna control signal that indicates a beam directing direction of the antenna based on the second beam scanning angle signal generated by the noise adding unit;
A beam scanning device comprising: A beam scanning device for controlling a beam having a non-uniform directivity gain,
A beam scanning angle selection unit that sequentially selects one of a plurality of predetermined beam scanning angles and generates a first beam scanning angle signal according to the selected beam scanning angle;
A noise generator that generates noise;
Obtained by setting a noise addition range based on the plurality of predetermined beam scanning angles and performing at least one of parallel movement or scaling on the noise generated by the noise generation unit according to the noise addition range An overrange processing unit that selects only random numbers within a predetermined range of random numbers;
A second value corresponding to the beam scanning angle obtained by adding the random number selected by the overrange processing unit to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selection unit. A noise adding unit that generates a beam scanning angle signal and updates a random number to be added at a predetermined time ;
A scanning angle control unit that generates an antenna control signal that indicates a beam directing direction of the antenna based on the second beam scanning angle signal generated by the noise adding unit;
A beam scanning device comprising:   The beam scanning apparatus according to claim 1, wherein the noise generation unit generates noise based on a quasi-random number.   The beam scanning apparatus according to claim 1, wherein the noise generation unit generates noise based on a pseudo random number.   The beam scanning apparatus according to claim 1, wherein the noise generation unit generates noise based on a physical random number. A beam scanning device for controlling a beam having a non-uniform directivity gain,
A beam scanning angle selection unit that sequentially selects one of a plurality of predetermined beam scanning angles and generates a first beam scanning angle signal according to the selected beam scanning angle;
The second beam corresponding to the beam scanning angle obtained by adding a random number based on a preset random number pattern to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selection unit. A noise addition unit that generates a scanning angle signal and updates a random number to be added at a predetermined time ;
A scanning angle control unit that generates an antenna control signal that indicates a beam directing direction of the antenna based on the second beam scanning angle signal generated by the noise adding unit;
A beam scanning device comprising: A beam scanning method for controlling a beam having a non-uniform directivity gain,
A beam scanning angle selection step of sequentially selecting one of a plurality of predetermined beam scanning angles and generating a first beam scanning angle signal according to the selected beam scanning angle;
Noise generation step for generating noise,
Obtained by setting a noise addition range based on the plurality of predetermined beam scanning angles and performing at least one of parallel movement or scaling on the noise generated by the noise generation step according to the noise addition range a random number, and generates a second beam scan angle signal corresponding to the beam scanning angle obtained by adding to the beam scan angle corresponding to the first beam scan angle signal generated by the beam scanning angle selection step A noise adding step for updating the random numbers to be added at a predetermined time ;
A scanning angle control step of generating an antenna control signal for instructing a beam directing direction of the antenna based on the second beam scanning angle signal generated by the noise adding step;
A beam scanning method comprising: A beam scanning method for controlling a beam having a non-uniform directivity gain,
A beam scanning angle selection step of sequentially selecting one of a plurality of predetermined beam scanning angles and generating a first beam scanning angle signal according to the selected beam scanning angle;
Noise generation step for generating noise,
Obtained by setting a noise addition range based on the plurality of predetermined beam scanning angles and performing at least one of parallel movement or scaling on the noise generated by the noise generation step according to the noise addition range An overrange processing step of selecting only random numbers within a predetermined range of random numbers;
A second value corresponding to the beam scanning angle obtained by adding the random number selected in the overrange processing step to the beam scanning angle corresponding to the first beam scanning angle signal generated in the beam scanning angle selection step. A noise addition step of generating a beam scanning angle signal and updating a random number to be added at a predetermined time ;
A scanning angle control step of generating an antenna control signal for instructing a beam directing direction of the antenna based on the second beam scanning angle signal generated by the noise adding step;
A beam scanning method comprising: A beam scanning method for controlling a beam having a non-uniform directivity gain,
A beam scanning angle selection step of sequentially selecting one of a plurality of predetermined beam scanning angles and generating a first beam scanning angle signal according to the selected beam scanning angle;
The second beam corresponding to the beam scanning angle obtained by adding a random number based on a preset random number pattern to the beam scanning angle corresponding to the first beam scanning angle signal generated by the beam scanning angle selection step. A noise addition step of generating a scanning angle signal and updating a random number to be added at a predetermined time ;
A scanning angle control step of generating an antenna control signal for instructing a beam directing direction of the antenna based on the second beam scanning angle signal generated by the noise adding step;
A beam scanning method comprising:

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