JP2022132749A - Radar device, projectile, guidance program - Google Patents

Abstract

To provide a radar device capable of detecting a target on a clutter source surface from above the target, a projectile using the radar device, and a guidance program using the radar device.SOLUTION: A radar device is mounted on a projectile and detects a target to guide the projectile to the target above a clutter source surface. An antenna of the radar device transmits a radar wave from above the target and receives at least a first-period reflected wave included in a radar reflected wave reflected by the target. A signal processing unit of the radar device detects the target based on a time from transmission of the radar wave to reception of the first period reflected wave and the first period reflected wave. The range of irradiation angles over which the transmitted radar waves are projected includes a normal direction of the clutter source surface.SELECTED DRAWING: Figure 2A

Description

The present invention relates to a radar system, a flying object using this radar system, and a guidance program used by this radar system. It can be suitably used for the flying object used and the guidance program used by this radar device.

When guiding a flying object such as an aircraft to a target such as a ship, there is a method of searching and tracking the target with a radar device mounted on the flying object. Here, surfaces such as the sea surface around a ship can be a clutter source that reflects radar waves to produce clutter waves with high power. As a result, when a radar device transmits a radar wave in a vertically downward direction to detect a target, the radar reflected wave reflected by the target may be buried in clutter waves, making detection difficult.

In order to avoid such a problem, there is a method in which the grazing angle between the surface of the clutter source such as the sea surface is made relatively small, and the flying object observes the ship from an oblique direction with respect to the ship. However, if a ship is also equipped with a radar device, the flying object enters the coverage area of the ship's radar device when the grazing angle is relatively small. As a result, the projectiles may be easily spotted by ships.

In relation to the above, Patent Document 1 (Japanese Unexamined Patent Publication No. 60-159668) discloses a radar device. This radar system is an aircraft-mounted radar system that measures the distance from an antenna on the antenna boresight axis to the ground using a sum channel signal and an elevation difference channel signal of a monopulse antenna. In this radar device, the distance tracking circuit includes a distance gate control circuit for controlling the sweep range of the distance gate in response to the altitude signal from the altitude sensor and the aircraft pitch angle signal from the attitude angle sensor, and a pulse width for controlling the transmission pulse width. and a control circuit.

Further, Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2000-329843) discloses a radar altimeter. The radar altimeter has a transmit and receive antenna. This radar altimeter is characterized in that a plurality of transmission antennas for both transmission and reception are attached at respective angles in order to change the radiation angle of the transmission antennas, and the plurality of transmission antennas are sequentially switched.

Further, Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2005-326228) discloses a radar device. This radar device transmits a broadband pulse signal via a transmitting/receiving antenna, receives the reflected wave as a received signal, and detects a target based on the received signal. This radar apparatus includes radar altitude estimation means, a storage unit, a control device, range compression means, clutter irradiation pattern calculation means, clutter scattering cross section estimation means, clutter suppression means, and target detection means. It is characterized by The radar altitude estimating means estimates the radar altitude based on the position information input. This storage unit associates and stores the directivity angle of the transmitting/receiving antenna and the received signal. This control device controls the directivity angle of the antenna pattern of the transmitting/receiving antenna in the elevation direction. The range compression means subjects the received signal received via the transmitting/receiving antenna to pulse compression processing, and stores the received signal after the pulse compression processing in the storage unit in association with the directivity angle information received from the control device. The clutter irradiation pattern calculation means calculates the clutter irradiation pattern based on the estimated radar altitude, information on the directivity angle from the control device, and the antenna pattern of the transmitting and receiving antennas measured in advance. The clutter scattering cross section estimating means calculates the clutter scattering cross section in each received signal from the calculated clutter irradiation pattern and the received signal after pulse compression processing corresponding to each directivity angle stored in the storage unit. presume. The clutter suppression means calculates a clutter suppression signal by suppressing the clutter power of each of the pulse-compressed received signals stored in the storage unit, using the estimated clutter scattering cross section. This target detection means detects a target from the calculated clutter suppression signal.

JP-A-60-159668 JP-A-2000-329843 JP-A-2005-326228

A radar system capable of detecting a target on a clutter source surface from above the target, a flying object using the radar system, and a guidance program used by the radar system are provided. Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

The means for solving the problems will be described below using the numbers used in (Mode for Carrying Out the Invention). These numbers are added to clarify the correspondence relationship between the description of the claims and the description of the invention. However, these numbers should not be used to interpret the technical scope of the invention described in (claims).

According to one embodiment, a radar device (2) is mounted on a projectile (1) to guide the projectile (1) to a target (8) above a clutter source surface (9). Detect target (8) at . The radar device (2) comprises an antenna (25) and a signal processing device (21). An antenna (25) transmits a radar wave from above the target (8) and receives at least a first period reflected wave included in the radar reflected wave reflected by the target (8). A signal processing device (21) detects a target (8) based on the time from transmitting a radar wave to receiving a reflected wave for the first period and the reflected wave for the first period. The range of illumination angles (20) over which the transmitted radar waves are illuminated includes the normal direction of the clutter source surface (9).

According to one embodiment, the guidance program is for realizing, by the computing device executing a process of guiding the projectile (1) to the target (8) above the clutter source surface (9). It is. The guidance program transmits a radar wave from above the target (8), receives the reflected wave for the first period included in the radar wave reflected at least by the target (8), and transmits the radar wave. and detecting the target (8) based on the first period reflected wave. The range of illumination angles (20) over which the transmitted radar waves are illuminated includes the normal direction of the clutter source surface (9).

According to one embodiment, targets above the clutter source surface can be detected from above the target.

FIG. 1 is a block circuit diagram showing one configuration example of a flying object according to one embodiment. FIG. 2A is a diagram illustrating an example of a grazing angle for a projectile target according to one related art. FIG. 2B is a graph showing an example of the relationship between the distance to the target and the received power of the reflected wave obtained from the target in a radar device according to a related technology. FIG. 3A is a block circuit diagram showing one configuration example of the radar device according to one embodiment. FIG. 3B is a block circuit diagram showing one configuration example of the signal processing device according to one embodiment. FIG. 3C is a plan view showing one configuration example of the antenna according to one embodiment. FIG. 4A is the first half of a flowchart showing one configuration example of a guidance program according to one embodiment. FIG. 4B is the second half of the flowchart showing one configuration example of the guidance program according to one embodiment. FIG. 5 is a diagram showing an example of beam irradiation range and range resolution of the radar device according to the embodiment. FIG. 6A is a diagram showing an example of a reflection source distribution pattern of radar reflected waves obtained by the radar apparatus according to one embodiment in a predetermined range cell. FIG. 6B is a diagram showing an example of a reflection source distribution pattern of radar reflected waves obtained by the radar apparatus according to one embodiment in a predetermined range cell. FIG. 6C is a diagram showing an example of a reflection source distribution pattern of radar reflected waves obtained by the radar apparatus according to one embodiment in a predetermined range cell. FIG. 6D is a diagram showing an example of a reflection source distribution pattern of radar reflected waves obtained by the radar apparatus according to one embodiment in a predetermined range cell. FIG. 6E is a diagram showing an example of a reflection source distribution pattern of radar reflected waves obtained by the radar apparatus according to one embodiment in a predetermined range cell. FIG. 7 is a graph showing an example of the relationship between the angle between the irradiation direction of the radar device and the target and the received power of the radar reflected wave obtained from the target according to the embodiment. FIG. 8A is a graph showing an example of the relationship between the distance to the target and the received power of the reflected wave obtained from the target, in the radar device according to the embodiment. FIG. 8B is a graph showing another example of the relationship between the distance to the target and the received power of the reflected wave obtained from the target, in the radar device according to the embodiment. FIG. 9A is a graph showing an example of the relationship between the distance to the target and the Σ power of the reflected wave obtained from the target, in the radar device according to the embodiment. FIG. 9B is a graph showing an example of the relationship between the angle with respect to the target and the Σ clutter reception power of the clutter reflected wave obtained from the target, in the radar device according to the embodiment. FIG. 9C is a graph showing an example of the relationship between the angle with respect to the target and the Δ clutter received power of the clutter reflected wave obtained from the target, of the radar device according to the embodiment. FIG. 10A is a graph showing an example of the relationship between the distance to the target and the Δpower of the reflected wave obtained from the target, in the radar device according to the embodiment. FIG. 10B is a graph showing an example of the relationship between the angle with respect to the target and the Σ target received power of the target reflected wave obtained from the target, in the radar device according to the embodiment. FIG. 10C is a graph showing an example of the relationship between the angle with respect to the target and the Δtarget received power of the target reflected wave obtained from the target, of the radar device according to the embodiment. FIG. 11A is the first half of a flowchart showing one configuration example of a guidance program according to one embodiment. FIG. 11B is the second half of the flowchart showing one configuration example of the guidance program according to one embodiment. FIG. 12 is a graph showing an example of the relationship between the distance to the target and the received power of the reflected wave obtained from the target in the radar device according to the embodiment. FIG. 13 is a diagram showing an example of beam irradiation range and range resolution of the radar device according to the embodiment. FIG. 14 is a graph showing an example of the relationship between the distance to the target and the received power of the reflected wave obtained from the target in the radar device according to the embodiment. FIG. 15 is a diagram showing another example of the beam irradiation range and range resolution of the radar device according to one embodiment. FIG. 16 is a graph showing another example of the relationship between the distance to the target and the received power of the reflected wave obtained from the target in the radar device according to the embodiment.

Embodiments for implementing the radar device, the flying object, and the guidance program according to the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
As shown in FIG. 1 , a flying object 1 according to one embodiment includes a radar device 2 , a control device 3 , an attitude control device 4 and a propulsion device 5 . The radar device 2 detects a target, generates a target detection signal indicating that the target has been detected, and a tracking angle control signal indicating the relative position of the target with respect to the flying object 1 , and transmits them to the control device 3 . Based on the tracking angle control signal, the control device 3 generates an attitude control signal for controlling the attitude control device 4 and transmits it to the attitude control device 4 . The control device 3 also generates a propulsion control signal for controlling the propulsion device 5 based on the target detection signal and transmits the propulsion control signal to the propulsion device 5 . The attitude control device 4 operates based on attitude control signals to control the attitude of the flying object 1 . The propulsion device 5 operates based on the propulsion control signal and controls the propulsion force of the flying object 1 .

As shown in FIG. 2A, a flying object 1A according to related technology includes a radar device 2A. The radar device 2A detects a target ship 8 from a detection distance _DA , and based on this detection, the flying object 1A 1A moves toward ship 8. Similarly, a flying object 1B according to the related art is equipped with a radar device 2B. The radar device 2B detects a target, a ship 8, from a detection distance _DB . move towards

In the example of FIG. 2A, ship 8 is above sea level 9 . Strictly speaking, the portion of the ship 8 above the sea surface 9 is the object to be detected as the target.

The ship 8 is equipped with another radar device for detecting the projectiles 1A, 1B and the like. This other radar device detects the flying object 1A existing inside the ship's radar coverage area 81, but does not detect the flying object 1B existing outside the ship's radar coverage area 81. From this point of view, in order to reach the ship 8 without being detected by the ship 8, it is better for the projectile 1B moving at a higher altitude HB than for the projectile _1A moving at a lower altitude _HA . Advantageous. Here, the sea level 9 is both the reference for the altitude _HA of the flying object _1A and the reference for the altitude HB of the flying object 1B. In other words, the distance from the flying object 1A to the sea surface 9 is called altitude _HA , and the distance from the flying object 1B to the sea surface 9 is called altitude _HB .

On the other hand, the higher the altitudes H _A and H _B of the flying bodies 1A and 1B, the more difficult it is for the radar devices 2A and 2B to detect the ship 8 . The higher the altitudes H _A and H _B of the flying bodies 1A and 1B, the greater the grazing angles A _A and A _B between the straight line connecting each of the flying bodies 1A and 1B and the ship 8 and the sea surface 9. . The larger the grazing angles A _A and A _B are, the larger the reception power of the clutter reflected waves, which are the radar waves transmitted by the radar devices 2 A and 2 B and reflected by the sea surface 9 . The larger the received power of the clutter reflected wave, the more difficult it becomes to distinguish between the target reflected wave reflected by the ship 8 and the clutter reflected wave.

Furthermore, as shown in FIG. _2B , the received power of the target reflected _wave is Preferably, the target received power is well above the noise level. In FIG. 2B, a graph GA represents an example of the relationship between the detected distance _DA between the flying object _1A and the ship 8 and the received power of clutter reflected waves from the sea surface 9 received by the radar device 2A. Similarly, a graph _GB represents an example of the relationship between the detected distance DB between the flying object _1B and the ship 8 and the received power of clutter reflected waves from the sea surface 9 received by the radar device 2B. Since the distance from the radar device 2A to the sea surface 9 is the altitude _HA , the power received by the radar device 2A at the detection distance _HA is the clutter reflected power from the sea surface 9, as can be read from the graph _GA . Similarly, since the distance from the radar device 2B to the sea surface 9 is the altitude _HB , the power received by the radar device 2B at the detection distance _HB is the clutter reflected power from the sea surface 9, as can be read from the graph _GB . .

Thus, there is a trade-off relationship between the fact that the flying bodies 1A and 1B are not detected by the target ship 8 and that the radar devices 2A and 2B of the flying bodies 1A and 1B can detect the target ship 8. It is in.

It will be explained that according to one embodiment, the projectile 1 can detect the ship 8 in a vertically downward direction or in a direction close thereto.

As shown in FIG. 3A, the radar device 2 according to one embodiment includes a signal processing device 21, a transmitter 22, a circulator 23, a monopulse comparator 24, an antenna 25, and a receiver 26. The signal processing device 21 includes a pulse code generator 211 , a target detection processing section 212 and a tracking processing section 213 . The monopulse comparator 24 includes a Σ signal generator 241 and a Δ signal generator 242 . The antenna 25 has antenna elements 251 and 252 .

As shown in FIG. 3B, the signal processing device 21 may be configured as a calculator such as a computer. In the example of FIG. 3B, the signal processing device 21 comprises a bus 200, an arithmetic device 201, a storage device 202, and an interface 205. A bus 200 connects an arithmetic device 201, a storage device 202, and an interface 205 so that they can communicate with each other. Interface 205 is connected to pulse code generator 211 and control device 3 .

The arithmetic device 201 implements the functions of the signal processing device 21 by executing programs stored in the storage device 202 . The storage device 202 stores a target detection program 203 for realizing the function of the target detection processing section 212 and a tracking program 204 for realizing the function of the tracking processing section 213 . Target detection program 203 may further implement the function of controlling pulse code generator 211 . The storage device 202 may further store an observation program for implementing observation processing, which will be described later. Part or all of the observation program, the target detection program 203 and the tracking program 204 may be collectively referred to as a guidance program executed by the arithmetic device 201 to realize the functions of the radar device 2 . These programs may be read from the recording medium 206 and stored in the storage device 202 .

As shown in FIG. 3C, the antenna 25 according to one embodiment is an array antenna comprising a first antenna group 253 including antenna elements 251 and a second antenna group 254 including antenna elements 252 . In the example of FIG. 3C, the first antenna group 253 is arranged in the first area 255 and the second antenna group 254 is arranged in the second area 256 different from the first area 255 . The first region 255 and the second region 256 may have a point-symmetric positional relationship with respect to the center of the antenna 25 .

4A and 4B, the operation of the flying object 1 and the radar device 2 according to the embodiment, that is, one configuration example of the guidance program according to the embodiment will be described. It can also be said that FIGS. 4A and 4B represent one configuration example of the target detection method according to one embodiment.

When the projectile 1 is sufficiently close to the target ship 8, the flow charts of FIGS. 4A and 4B begin. The arithmetic unit 201 may execute a predetermined program to detect that the flying object 1 has sufficiently approached the ship 8 . As an example, the arithmetic unit 201, based on the position information of the projectile 1 measured by GNSS (Global Navigation Satellite System) and the position information of the ship 8 pre-stored in the projectile 1 , it may be detected that the projectile 1 has sufficiently approached the ship 8 .

When the flowcharts of FIGS. 4A and 4B start, the radar device 2 starts observation processing in step S01. In step S<b>01 , arithmetic device 201 executes target detection program 203 to control pulse code generator 211 . A pulse code generator 211 generates a pulse code under the control of the arithmetic unit 201 . The transmitter 22 generates and outputs a radar wave based on the pulse code. The radar wave is transmitted to the antenna 25 via the circulator 23 and the Σ signal generator 241, and is transmitted to the first antenna group 253 including the first antenna element 251 and the second antenna group 254 including the second antenna element 252. is transmitted to the outside of the flying object 1 by.

Radar waves reflect off a ship 8 as a target and/or a sea surface 9 as a clutter source surface. A reflected radar wave is called a radar reflected wave. Radar reflected waves are received by a first antenna group 253 including first antenna element 251 and a second antenna group 254 including second antenna element 252 . A portion of the radar reflected wave received by the first antenna group 253 is called a first area reflected wave. Similarly, the portion of the radar reflected wave received by the second antenna group 254 is called a second area reflected wave.

The monopulse comparator 24 receives the first area reflected wave and the second area reflected wave from the antenna 25 . The Σ signal generator 241 generates a Σ signal representing the sum of the first area reflected wave and the second area reflected wave based on the first area reflected wave and the second area reflected wave. The Δ signal generator 242 generates a Δ signal representing the difference between the first area reflected wave and the second area reflected wave based on the first area reflected wave and the second area reflected wave.

The receiver 26 receives the Σ signal and the Δ signal and transmits them to the signal processing device 21 . At this time, the Σ signal may be transmitted from the Σ signal generator 241 to the receiver 26 via the circulator 23 .

In step S02, the target detection processing unit 212 starts target detection processing. The target detection processing unit 212 receives the Σ signal, and from the first time when a predetermined time has passed since the radar wave was transmitted in the Σ signal, the second time when a predetermined time interval has passed from the first time. A portion derived from the radar reflected waves received during the time interval up to the time is extracted. Similarly, the target detection processing unit 212 receives the Δ signal and extracts the portion of the Δ signal derived from the radar reflected waves received at the same time interval.

Extraction of a part from each of the Σ signal and the Δ signal will be described. When the speed of propagation of radar waves and radar reflected waves between the radar device 2 and the ship 8 or the sea surface 9 is constant and uniform, the radar waves are received at predetermined time intervals based on the transmission time of the radar waves. The radar-reflected wave is a radar-reflected wave reflected in a predetermined area based on the position where the radar device 2 transmitted the radar wave. In other words, the first distance is the distance that the radar wave propagated from the time when the radar wave was transmitted from the radar device 2 to the first time, and the distance that the radar wave propagated from the time when the radar wave was transmitted from the radar device 2 to the second time. is the second distance, the radar reflected wave received by the radar device 2 in the first period from the first time to the second time is a region included in the range from half the first distance to half the second distance is reflected on the surface of an object existing in

As shown in FIG. 5, when the radar device 2 of the flying object 1 positioned above the ship 8 above the sea surface 9 transmits a radar wave toward the ship 8, the irradiation angle at which the radar wave is transmitted is A region inside the beam irradiation range 20, which is a range, can be virtually divided into a plurality of range cells R _N−1 , R _N , R _N+1 , R _N+2 , R _N+3 , etc. based on the distance from the radar device 2. can. For example, as range cell R _N-1 , a space from D _N-1 to D _N from the radar device 2 in the beam irradiation range 20 is defined. Similarly, a range cell RN defines a space from _DN to _{DN +1} from the radar device 2 in the beam irradiation range 20 . As a range cell RN ₊₁ , a space in the beam irradiation range 20 whose distance from the radar device 2 is from _DN+1 to _DN+2 is defined. As a range cell RN ₊₂ , a space in the beam irradiation range 20 whose distance from the radar device 2 is from _DN+2 to _DN+3 is defined. As a range cell RN ₊₃ , a space in the beam irradiation range 20 whose distance from the radar device 2 is from _DN+3 to _DN+4 is defined. These definitions are performed by the arithmetic device 201 of the signal processing device 21, for example. At this time, the width of each range cell in the direction of the distance from the radar device 2 is constant, and this width is called range resolution ΔR. An appropriate value may be stored in advance in the storage device 202 as the value of the range resolution ΔR. Also, an appropriate initial value of the range resolution ΔR may be stored in advance in the storage device 202, and the calculation device 201 may determine the value of the range resolution ΔR by adjusting this initial value based on radar reflected waves and the like. . Note that the maximum value Nmax may be set for the range cell number. At this time, the search range of the radar device 2 is the range from the radar device 2 to the outer surface of the range cell _RNmax in the beam irradiation range 20 . According to the notation of FIG. 5, the search range of the radar device 2 is the range from the radar device 2 to the distance D _Nmax+1 in the beam irradiation range 20 . Here, the maximum value Nmax can be set to any numerical value. Since the search range of the boundary between the target and the clutter source is determined by the maximum value Nmax, the maximum value Nmax may be set in advance to an appropriate value corresponding to the target altitude. The maximum value Nmax may be controlled.

In the following description, the boundary of each range cell is defined by the distance from the radar device 2. These distances correspond to the time that has elapsed since the radar wave was transmitted from the radar device 2. Therefore, these distances can be read as corresponding times. For example, the range resolution ΔR as a distance can be read as the above time interval. By dividing the received radar reflected wave by the time interval in the arithmetic unit 201, it can be read as the reflected power in the corresponding range cell, and the presence or absence of the reflected object can be analyzed for each range.

In the example of FIG. 5, the sea surface 9 as the surface of the clutter source is approximated to a horizontal plane, and the flying object 1 is moving vertically downward, which is the normal direction of the sea surface 9. The center of the irradiation angle range for transmitting radar waves is also the vertically downward direction, but one embodiment is not limited to this example. One embodiment may be, for example, the ground where the clutter source surface is slanted with respect to the horizontal. In this case, the projectile 1 may be moving in the normal direction of the ground. Moreover, although it is preferable that the irradiation angle range of the radar device 2 includes the normal direction of the clutter source surface, even if the center of the irradiation angle range does not coincide with the normal direction of the clutter source surface, good. By moving in this way, it is expected that the projectile 1 will be less likely to be discovered by the target. For example, as shown in FIG. 2A, the ship radar coverage 81 of the ship 8 is centered on a direction parallel to the sea surface 9 as the clutter source surface, and up to a predetermined angle range with respect to the normal direction of the sea surface 9. When the projectile 1 is spread out, it can move outside the ship's radar coverage area 81 of the ship 8 when it approaches the ship 8 as a target, and is expected to be difficult to be detected by the ship 8 . In addition, by irradiating the radar wave from the normal direction of the clutter source surface, the boundary between the target and the clutter source surface becomes parallel to the boundary of the range cell, and the radar reflected wave from the target and the radar reflected wave from the clutter source are separated. It becomes possible.

FIG. 6A shows a reflector distribution pattern 70 _N representing the distribution of reflectors estimated based on the distribution of received power of radar reflected waves obtained from reflectors existing in the range cell R _N-1 shown in FIG. An example of ₋₁ is shown. However, in the example of FIG. 6A, neither the ship 8 nor the sea surface 9 exist in the range cell RN _-1 . Therefore, in the range cell R _N-1 , the radar reflected wave of the radar wave reflected by the ship 8 or the sea surface 9 is not obtained, and the reflection source distribution pattern 70 _N-1 is blank.

FIG. _6B shows an example of a reflection source distribution pattern _70N of radar reflected waves obtained in the range cell RN shown in FIG. A ship 8 exists in the range cell _RN , but the sea surface 9 does not exist. Therefore, the reflection source distribution pattern 70 _N includes the target reflection pattern 80 _N of the radar wave reflected by the ship 8 .

FIG. 6C shows an example of a reflection source distribution pattern 70 _N+1 of radar reflected waves obtained in the range cell RN ₊₁ shown in FIG. A ship 8 exists in the range cell RN ₊₁ , but a sea surface 9 does not exist. Therefore, the reflection source distribution pattern 70 _N+1 includes the target reflection pattern 80 _N+1 of the radar wave reflected by the ship 8 .

FIG. 6D shows an example of a reflection source distribution pattern 70 _N+2 of radar reflected waves obtained in the range cell RN ₊₂ shown in FIG. A ship 8 and a surface 9 are present in the range cell RN ₊₂ . Therefore, the reflection source distribution pattern 70 _N+2 includes a target reflection pattern 80 _N+2 of the target reflected waves of the radar waves reflected by the ship 8 and a clutter reflection pattern 90 _N+2 of the clutter reflected waves of the radar waves reflected by the sea surface 9 . ing.

FIG. 6E shows an example of a reflection source distribution pattern 70 _N+3 of radar reflected waves obtained in the range cell RN ₊₃ shown in FIG. There is no ship 8 in range cell RN ₊₃ , but there is sea surface 9. Therefore, the reflection source distribution pattern 70 _N+3 includes a clutter reflection pattern 90 _N+3 of the clutter reflected waves of the radar waves reflected by the sea surface 9 .

In this way, the target detection processing unit 212 extracts components corresponding to the range cells R _N−1 , R _N , R _N+1 , R _N+2 , R _N+3 and the like from the Σ signal and the Δ signal.

FIG. 7 shows an example of the relationship between the angle between the irradiation direction of the radar device 2 and the target and the received power of the radar reflected wave obtained from the target. FIG. 7 contains two graphs G _1Σ and G _1Δ . Graph _G1Σ represents Σ power, which is the received power of the Σ signal. Graph _G1Δ represents the Δ power, which is the received power of the Δ signal. When the angle between the irradiation direction of the radar device 2 and the target is zero, in other words, when the target exists in the center of the irradiation angle range of the radar device 2, the Σ power becomes maximum and the Δ power becomes zero.

The target detection processing unit 212 determines whether the Σ power is sufficiently greater than the noise level. In other words, it is determined whether or not the power difference obtained by subtracting the noise level from the Σ power is greater than a predetermined threshold TH1. If this power difference is smaller than the threshold TH1, it is presumed that it cannot be determined whether or not the Σ power is derived from the ship 8 as the target. The threshold TH1 is appropriately set based on the noise level that depends on the radar device 2 and the target received power representing the received power of the portion derived from the target.

Returning to FIG. 4A, as an example, when the range cell to be processed is denoted by number _{i and the Σ power obtained in range cell Ri is represented by Σ i ,
Σi} - noise level > TH1
is not satisfied (NO), the process of the flowchart in FIG. 4A proceeds to step S03. Conversely, if the above conditions are satisfied (YES), the process proceeds to step S04.

In step S03, the target detection processing unit 212 increments the number i of the range cell to be processed, and repeats the processing of step S02 for the next range cell. In other words, the target detection processing unit 212 sets the range cell number i to i+1, and the process proceeds to step S02. The number i of the range cell targeted for the determination process may be initialized, for example, in step S01, before step S02 is first executed.

By repeating steps S02 and S03 in this way, the target detection processing unit 212 detects a range cell from which Σ power sufficiently higher than the noise level is obtained. As shown in FIGS. 8A and 8B, in the range cells R _{N −1} and R _N , the power difference obtained by subtracting the noise level from the Σ power represented by the graph G _2Σ is smaller than the threshold TH1. The power difference obtained by subtracting the noise level is greater than the threshold TH1. In these cases, the process of the flowcharts of FIGS. 4A and 4B proceeds to step S04 while the number i of the range cell to be processed is set to N+1.

In step S04, the target detection processing unit 212 determines whether or not the power difference obtained by subtracting the Σ power of the previous range cell from the Σ power of the current range cell of interest is smaller than a predetermined threshold TH2. For example, when the currently focused range cell number is i, Σi-1, which is the Σ power of the previous range cell R _{i -1 ,} is subtracted from Σ _i , which is the Σ power of this range cell Ri i. Determine whether the power difference is less than a threshold TH2.

As shown in FIG. 9A, the Σ power sharply drops from the clutter received power to the target received power immediately after and immediately before the distance from the radar apparatus 2 reaches the sea surface 9 as the surface of the clutter source. This dip is called a dip power for convenience. Here, the curved portion of the graph G1 in FIG. 9A shows an example of the relationship between the distance from the radar device 2 to the sea surface 9 as the surface of the clutter source and the received clutter power. This is because the sea surface 9 as a clutter source surface exists in a wide range of irradiation angles for transmitting radar waves, as shown in examples of range cells RN ₊₂ in FIGS. This is because the Σ power is generally large in the containing range cells, as shown in FIG. 9B. In addition, as shown in FIG. 9C, the Δ power is generally large under the same conditions.

The target detection processing unit 212 can determine whether or not the range cell of interest includes the sea surface 9 as the clutter source surface by detecting the drop power shown in FIG. 9A. Therefore, when the power difference obtained by subtracting Σ _i−1 from Σ _i is equal to or greater than the threshold TH2, it can be estimated that the radar reflected wave of the currently focused range cell originates from the sea surface 9 as the surface of the clutter source. There is a possibility that the radar reflected waves originating from the ship 8 have not been received. The threshold TH2 is appropriately set based on the clutter received power representing the received power derived from the clutter source surface and the target received power representing the received power derived from the target.

Returning to FIG. 4A, as an example, when the currently focused range cell number is i,
Σ _i −Σ _i−1 < TH2
is not satisfied (NO), the process of the flowchart in FIG. 4A proceeds to step S05. In the example of FIG. 8B, when the currently focused range cell number i is _N + ₁ , ΣN, which is the power of the Σ signal of the range cell RN, is changed from _ΣN +1, which is the power of the Σ signal of the range cell RN ₊₁ . It is determined that the subtracted power difference is equal to or greater than the threshold TH2, and the process proceeds to step S05. Conversely, if the above conditions are satisfied (YES), the process proceeds to step S06. In the example of FIG. 8A, when the currently focused range cell number is _N + ₁ , ΣN, which is the power of the Σ signal of range cell RN+1, is subtracted from _{ΣN +1} , which is the power of Σ signal of range cell RN+1. The resulting power difference is determined to be smaller than the threshold TH2, and the process proceeds to step S06.

In step S05, the target detection processing unit 212 finely adjusts the irradiation direction of the radar wave beam so that the ship 8 as a target can be captured within the irradiation angle range for transmitting the radar wave. The process of the flow chart of 1 returns to step S01 and is repeated.

In step S06, the target detection processing unit 212 determines whether or not the power difference obtained by subtracting the .DELTA. power from the .SIGMA. power in the currently focused range cell is greater than a predetermined threshold TH3. In the example of FIGS. 8A and 8B, graph G _2Σ represents Σ power and graph G _2Δ represents Δ power.

As shown in FIG. 10A, when the range cell of interest does not include the sea surface 9 as the clutter source surface and includes the ship 8 as the target, if the irradiation If the target is captured at the center of the angular range, the power difference obtained by subtracting the Δ power from the Σ power of this range cell will be sufficiently large. As shown in FIGS. 10B and 10C, the target ship 8 exists in a narrow central portion of the irradiation angle range for transmitting radar waves, and the sea surface 9 as the clutter source surface is included. This is because the Σ power is high and the Δ power is low in a range cell that does not have any.

The target detection processing unit 212 determines whether or not the power difference shown in FIG. 10A is greater than the threshold TH3 shown in the range cell RN ₊₁ in FIGS. 8A and 8B. It can be determined whether the ship 8 exists in the central portion of the range of irradiation angles to be transmitted. Therefore, when the power difference obtained by subtracting the Δ power from the Σ power of the range cell of interest is greater than the threshold value TH3, it is assumed that the target ship 8 is in the central portion of the irradiation angle range for transmitting radar waves in that range cell. can be estimated. Conversely, if this power difference is equal to or less than the threshold TH3, the ship 8 as the target in that range cell is out of the central portion of the irradiation angle range for transmitting radar waves, or some kind of erroneous detection has occurred. can be estimated. The threshold TH3 is appropriately set based on the target received power representing the received power derived from the target.

Returning to FIG. 4B, as an example, when the currently focused range cell number is i,
Σ _i −Δ _i > TH3
is not satisfied (NO), the process of the flowchart in FIG. 4B proceeds to step S07. Conversely, if the above conditions are satisfied (YES), the process proceeds to step S08.

The processing of step S07 is the same as the processing of step S05 described above.

In step S08, the signal processing device 21 performs monopulse tracking processing. Here, the target detection processing unit 212 generates a target detection signal indicating that the ship 8 as a target has been detected, and transmits the target detection signal to the control device 3 . In addition, the target detection processing unit 212 generates angle tracking range cell information representing a range cell in which the ship 8 as the detected target exists, and transmits the angle tracking range cell information to the tracking processing unit 213 . Further, the tracking processing unit 213 generates a tracking angle control signal representing the relative position of the target with respect to the projectile 1 based on the angle tracking range cell information, and transmits the tracking angle control signal to the control device 3 .

In step S09, the control device 3 performs tracking angle control. Here, the control device 3 controls the attitude control device 4 and the propulsion device 5 based on the target detection signal and the tracking angle control signal so that the projectile 1 reaches the target ship 8. Perform terminal control of the projectile 1.

When step S09 is completed, the flowcharts of FIGS. 4A and 4B end.

Thus, according to the radar device 2, the projectile 1, and the guidance program according to one embodiment, the target ship 8 existing on the sea surface 9 as the clutter source surface is Detection can be performed from above while moving vertically downward, for example.

(Second embodiment)
In this embodiment, the following changes are added to the first embodiment described above. That is, processing is added to match the boundary between any two adjacent range cells with the sea surface 9 as the clutter source surface. This is because when the range cell boundary is shifted from the sea surface 9, there is a range cell where the ship 8 and the sea surface 9 exist, and in such a range cell, the power difference between the clutter received power and the target received power is sufficiently large. This is to reduce the possibility that the target may be difficult to detect due to the absence of the target.

11A and 11B are flow charts showing one configuration example of the guidance program according to the present embodiment. The flowcharts of FIGS. 11A and 11B are obtained by adding steps S16, S17, S18 and S19 to the flowcharts of FIGS. 4A and 4B. In other words, steps S11, S12, S13, S14, S15, S20, S21, S22 and S23 of the flowcharts of FIGS. 11A and 11B correspond to steps S01, S02, S03 of the flowcharts of FIGS. Same as S04, S05, S06, S07, S08 and S09. However, in the flowcharts of FIGS. 11A and 11B, in step S14,
Σ _i −Σ _i−1 < TH2
is not satisfied (NO), the process proceeds to step S15, and conversely, if the above condition is satisfied (YES), the process proceeds to step S16.

In step S16, the target detection processing unit 212 determines whether the power difference obtained by subtracting the Σ power of the current range cell of interest from the Σ power of the next range cell is greater than a threshold TH4.

As shown in FIG. 12, when the boundary between range cells RN ₊₂ and RN ₊₃ is equal to sea level 9 as the clutter source surface, the power difference between the Σ powers of range cells RN ₊₂ and RN ₊₃ is sufficiently becomes larger and becomes larger than the threshold TH4. The threshold TH4 is appropriately set based on the clutter received power and the target received power when the boundary of the range cell is equal to the sea surface 9 as the surface of the clutter source. In the example of FIG. 12, graph _G3Σ represents Σ power and graph _G3Δ represents Δ power.

As an example, when the currently focused range cell number is i,
Σ _i+1 −Σ _i >TH4
is not satisfied (NO), the process of the flowcharts of FIGS. 11A and 11B proceeds to step S17. Conversely, if the above conditions are satisfied (YES), the process proceeds to step S20.

As shown in FIG. 13, when the range cell boundaries do not sufficiently coincide with the sea level 9 as the clutter source surface, the range cell RN ₊₂ , in particular, contains the ship 8 as the target and the sea level 9 as the clutter source surface. As indicated by 14, the power difference between the Σ powers of the range cell RN ₊₂ and its adjacent range cell RN ₊₃ is not sufficiently large, and the above condition regarding the threshold TH4 is not satisfied. In the example of FIG. 14, graph _G4Σ represents Σ power and graph _G4Δ represents Δ power.

In step S17, the range cell number i is incremented, and the process proceeds to step S18. In step S18, it is determined whether or not the incremented range cell number i has reached the maximum range cell number Nmax. If the range cell number i is smaller than the maximum range cell number Nmax (YES), the process of step S16 is repeated for the i-th range cell. Conversely, if the range cell number i has reached the maximum range cell number Nmax (NO), the process proceeds to step S19.

In step S19, the target detection processing unit 212 reduces the range resolution ΔR by a minute range resolution adjustment value α, and repeats the process from step S11. This iterative process may continue until the above conditions are met, ie, until the boundary of the range cell of interest is sufficiently close to the sea surface 9 as the clutter source surface.

As shown in FIG. 15, as a result of reducing the range resolution ΔR by a small range resolution adjustment value α, the boundary between the range cells RN ₊₂ and RN ₊₃ is sufficiently aligned with the sea surface 9 as the clutter source surface. Then, as shown in FIG. 16, the difference in Σ power between the range cells RN ₊₂ and RN ₊₃ becomes sufficiently large, and the above condition regarding the threshold TH4 is satisfied. In the example of FIG. 16, graph _G5Σ represents Σ power and graph _G5Δ represents Δ power.

Other steps in the flow charts of FIGS. 11A and 11B are similar to the corresponding steps of FIGS. 4A and 4B and will not be described in further detail.

Thus, according to the present embodiment, it is possible to detect a target with higher accuracy than in the first embodiment.

The invention made by the inventor has been specifically described above based on the embodiments, but the present invention is not limited to each embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say. Moreover, each feature described in each embodiment can be freely combined within a technically consistent range.

The radar device 2 described in each embodiment is understood as follows, for example.

(1) A radar device 2 according to a first aspect is mounted on a flying object 1 and detects a target 8 in order to guide the flying object 1 to the target 8 above the clutter source surface 9. is. This radar device 2 includes an antenna 25 and a signal processing device 21 . This antenna 25 transmits a radar wave from above the target 8 and receives at least the first period reflected wave included in the radar reflected wave reflected by the target 8 . The signal processing device 21 detects the target 8 based on the time from transmitting the radar wave to receiving the reflected wave for the first period and the reflected wave for the first period. The irradiation angle range 20 for irradiating radar waves includes the normal direction of the clutter source surface 9 .

The radar device 2 according to the first aspect has the effect of being able to detect the target 8 from above the target 8 .

(2) The radar device 2 according to the second aspect is the radar device 2 according to the first aspect, in which the reflected wave for the first period is the radar reflected wave for the first time after the radar wave is transmitted. is the portion received during a first time period between a first time after which has passed and a second time after which a first time interval has passed.

The radar device 2 according to the second aspect has the effect of being able to detect the target 8 by dividing the radar reflected wave by the time from transmitting the radar wave to receiving the radar reflected wave. .

(3) The radar device 2 according to the third aspect is the radar device 2 according to the second aspect, in which the antenna 25 is included in the radar reflected wave for a second period different from the first period reflected wave. Receive more reflected waves. The 0th period reflected wave is a portion of the radar reflected wave received during the 0th period between the first time and the 0th time before the first time interval elapses before the first time. The signal processing device 21 detects the target 8 further based on the time from transmission of the radar wave to reception of the 0th period reflected wave and the 0th period reflected wave.

The radar device 2 according to the third aspect has the effect of being able to detect the target 8 while suppressing the influence of noise and the like by dividing the radar reflected wave into a plurality of parts and processing them.

(4) The radar device 2 according to the fourth aspect is the radar device 2 according to the third aspect, in which the antennas 25 include a first antenna group 253 arranged in the first region 255 and and a second antenna group 254 arranged in a second region 256 different from the second antenna group 254 . The first antenna group 253 receives the first area reflected waves reaching the first area 255 among the radar reflected waves. The second antenna group 254 receives the second area reflected waves reaching the second area 256 among the radar reflected waves. The radar device 2 further comprises a monopulse comparator 24 . The monopulse comparator 24 generates a Σ signal representing the sum of the first area reflected wave and the second area reflected wave, and a Δ signal representing the difference between the first area reflected wave and the second area reflected wave. The signal processing device 21 detects the target further based on the Σ signal and the Δ signal.

The radar device 2 according to the fourth aspect detects the center of the reflection angle range of the radar wave based on the Σ signal and the Δ signal representing the sum and the difference of the radar reflected waves respectively received by the two antenna groups. It is possible to detect whether or not the target 8 is captured by

(5) The radar device 2 according to the fifth aspect is the radar device 2 according to the fourth aspect, in which the signal processing device 21 includes a first period Σ signal, a first period Δ signal, and a second period Σ signal. The first period .SIGMA. represents the sum of The first period delta signal represents the difference between the first period first area reflected wave and the first period second area reflected wave. The 0th period Σ signal is the 0th period 1st area reflected wave received by the first antenna group 253 and the 0th period 2nd area reflected wave received by the second antenna group 254 among the 0th period reflected waves. represents the sum of The signal processing apparatus 21 calculates the first period Σ received power representing the received power of the Σ signal in the first period, the first period Δ received power representing the received power of the Δ signal in the first period, and the received power of the Σ signal in the 0th period. The target 8 is detected further based on the 0th period Σ received power representing .

The radar device 2 according to the fifth aspect captures the target 8 at the center of the range of reflection angles of the radar wave based on the power of the Σ signal and Δ signal in the same period and the power of the Σ signal in adjacent periods. It is possible to detect whether or not the object is cluttered, and to detect the target 8 separately from the clutter source surface 9 .

(6) The radar device 2 according to the sixth aspect is the radar device 2 according to the fifth aspect, in which the signal processing device 21 subtracts a predetermined noise level from the first period Σ received power The difference is larger than the first threshold TH1, and the second power difference obtained by subtracting the 0th period Σ received power from the first period Σ received power is smaller than the second threshold TH2, and the first period Σ received power minus the first When the third power difference obtained by subtracting the received power for the period Δ is larger than the third threshold TH3, it is determined that the target 8 has been detected in the space where the radar wave was reflected as the reflected wave for the first period. The first threshold TH1 is set based on the noise level and the target received power representing the received power of the part of the radar reflected wave that originates from the target 8 . The second threshold TH2 is set based on the clutter received power representing the received power of the portion of the radar reflected wave derived from the clutter source surface 9 and the target received power. The third threshold TH3 is set based on the target received power.

In the radar device 2 according to the sixth aspect, the Σ power in the period of interest is sufficiently larger than the noise level, the Σ power in the period of interest is estimated not to be derived from the clutter source surface 9, and the radar wave is There is an effect that it is possible to determine that the target 8 has been detected when it is estimated that the target 8 exists in the central portion of the range of irradiation angles to be transmitted.

(7) The radar device 2 according to the seventh aspect is the radar device 2 according to the fifth aspect, in which the antenna 25 includes both the 0th period reflected wave and the 1st period reflected wave included in the radar reflected wave. Another second period reflected wave of the radar wave reflected at least by the clutter source surface 9 is further received during a second period between the second time and a third time when the first time interval has elapsed from the second time. do. The signal processing device 21 determines the difference between the second period first area reflected waves received by the first antenna group 253 and the second period second area reflected waves received by the second antenna group 254 among the second period reflected waves. A second period Σ signal representing the sum is also generated. The signal processing device 21 subtracts the predetermined noise level from the first period Σ received power, and the first power difference is greater than the first threshold TH1, and the 0th period Σ received power is subtracted from the first period Σ received power. The second power difference is smaller than the second threshold TH2, and the third power difference obtained by subtracting the first period Δ received power from the first period Σ received power is larger than the third threshold TH3, and the second period Σ signal When the fourth power difference obtained by subtracting the first period Σ received power from the second period Σ received power representing the received power is greater than a fourth threshold TH4, the radar wave is reflected as the reflected wave for the first period. is detected. The first threshold TH1 is set based on the noise level and the target received power representing the received power of the part of the radar reflected wave that originates from the target 8 . The second threshold TH2 is set based on the clutter received power representing the received power of the portion of the radar reflected wave derived from the clutter source surface 9 and the target received power. The third threshold TH3 is set based on the target received power. The fourth threshold TH4 is set based on the clutter received power and the target received power when the distance from the antenna 25 to the clutter source surface 9 is equal to the distance propagated by the radar wave by the third time. .

In the radar device 2 according to the seventh aspect, the Σ power in the period of interest is sufficiently larger than the noise level, the Σ power in the period of interest is estimated not to be derived from the clutter source surface 9, and the radar wave is It is estimated that the target 8 exists in the central portion of the range of irradiation angles to be transmitted, and the Σ power for the period of interest is derived from the target 8, and the Σ power for the period next to the period of interest is derived from the clutter source surface 9. The effect is that it can be determined that the target 8 has been detected when it is estimated that this is the case.

(8) The radar device 2 according to the eighth aspect is the radar device 2 according to the fifth aspect, in which the antenna 25 includes both the 0th period reflected wave and the 1st period reflected wave included in the radar reflected wave. Another second period reflected wave reflected by at least the target 8 is a second period between a third time after the second time and a fourth time when the first time interval has passed from the third time. to receive more. The antenna 25 receives the 3rd period reflected wave, which is different from the 0th period reflected wave, the 1st period reflected wave, and the 2nd period reflected wave included in the radar reflected wave, and is the radar wave reflected at least by the clutter source surface 9. It is further received during a third time period between a fourth time and a fifth time after the first time interval has elapsed from the fourth time. The signal processing device 21 determines the difference between the second period first area reflected waves received by the first antenna group 253 and the second period second area reflected waves received by the second antenna group 254 among the second period reflected waves. A second period Σ signal representing the sum, a third period first area reflected wave received by the first antenna group 253 among the third period reflected wave, and a third period second area received by the second antenna group 254 A third period Σ signal representing the sum with the reflected wave is further generated. The signal processing device 21 determines that a first power difference obtained by subtracting a predetermined noise level from the first period Σ received power is greater than a first threshold TH1, and subtracting the 0th period Σ received power from the first period Σ received power. is smaller than a second threshold TH2, and a third power difference obtained by subtracting the first period Δ received power from the first period Σ received power is larger than a third threshold TH3, and the third period Σ signal When the fourth power difference obtained by subtracting the second period Σ received power representing the received power of the second period Σ signal from the third period Σ received power representing the received power of the second period Σ signal is greater than the fourth threshold TH4, the radar wave is detected in the second It is determined that the target 8 is detected in the space reflected as the period reflected wave. The first threshold TH1 is set based on the noise level and the target received power representing the received power of the part of the radar reflected wave that originates from the target 8 . The second threshold TH2 is set based on the clutter received power representing the received power of the portion of the radar reflected wave derived from the clutter source surface 9 and the target received power. The third threshold TH3 is set based on the target received power. The fourth threshold TH4 is set based on the clutter received power and the target received power when the distance from the antenna 25 to the clutter source surface 9 is equal to the distance propagated by the radar wave by the third time. .

In the radar device 2 according to the eighth aspect, the Σ power in the period of interest is sufficiently larger than the noise level, the Σ power in the period of interest is estimated not to be derived from the clutter source surface 9, and the radar wave is It is estimated that the target 8 exists in the central portion of the range of irradiation angles to be transmitted, and the Σ power in the period after this period of interest is derived from the target 8, and the Σ power in the period next to the period after this is derived from the target 8. The effect is that it can be determined that the target 8 has been detected when the clutter source surface 9 is presumed to be the source of the clutter.

(9) The radar device 2 according to the ninth aspect is the radar device 2 according to the seventh or eighth aspect, wherein the signal processing device 21, when the fourth power difference is smaller than the fourth threshold TH4, The one time interval is reduced by a second time interval and the process of detection is repeated using the reduced first time interval.

In the radar apparatus 2 according to the ninth aspect, the time interval can be finely adjusted.

(10) The radar device 2 according to the tenth aspect is the radar device 2 according to the sixth to ninth aspects, and the signal processing device 21, when the second power difference is smaller than the first threshold TH1, The first time is delayed by a first time interval, and the process of detection is repeated using the delayed first time.

The radar device 2 according to the tenth aspect has the effect of being able to search for a period in which the Σ power is sufficiently higher than the noise level.

(11) The radar device 2 according to the eleventh aspect is the radar device 2 according to the sixth to tenth aspects, and the signal processing device 21, when the second power difference is greater than the second threshold TH2, The irradiation angle range is finely adjusted, and the detection process is repeated based on the Σ signal and Δ signal obtained by transmitting radar waves in the finely adjusted irradiation angle range.

The radar device 2 according to the eleventh aspect has the effect of being able to finely adjust the irradiation angle range until it is estimated that the Σ power in the period of interest is not derived from the clutter source surface 9 .

(12) The radar device 2 according to the twelfth aspect is the radar device 2 according to the sixth to eleventh aspects, and the signal processing device 21, when the second power difference is smaller than the third threshold TH3, The irradiation angle range is finely adjusted, and the detection process is repeated based on the Σ signal and Δ signal obtained by transmitting radar waves in the finely adjusted irradiation angle range.

The radar device 2 according to the twelfth aspect has the effect of being able to finely adjust the irradiation angle range 20 until the target 8 is estimated to be in the central portion of the irradiation angle range 20 .

(13) A flying object 1 according to a thirteenth aspect includes a radar device 2 according to the first to twelfth aspects, a control device 3, and an attitude control device 4. This control device 3 generates an attitude control signal based on the signal output by the radar device 2 based on the detection of the target 8 . This attitude control device 4 controls the attitude of the flying object 1 so that the flying object 1 moves toward the target 8 based on the attitude control signal.

The projectile 1 according to the thirteenth aspect has the effect that it can be guided to the target 8 based on the detection of the target 8 by the radar devices 2 according to the first to twelfth aspects.

(14) The guidance program according to the fourteenth aspect is a guidance program for realizing the process of guiding the projectile 1 to the target 8 above the clutter source surface 9 by the arithmetic unit 201 executing the process. . This guidance program transmits a radar wave from above the target 8, receives the reflected wave for the first period included in the radar reflected wave reflected by the target 8 at least, and transmits the radar wave. It includes detecting the target 8 based on the time to receive the reflected wave for one period and the reflected wave for the first period. The irradiation angle range 20 for irradiating radar waves includes the normal direction of the clutter source surface 9 .

The guidance program according to the first aspect has the effect that the target 8 can be detected from above the target 8 .

1, 1A, 1B flying object 2, 2A, 2B radar device 20 beam irradiation range (range of irradiation angle)
21 signal processing device 200 bus 201 arithmetic device 202 storage device 203 target detection program 204 tracking program 205 interface 206 recording medium 211 pulse code generator 212 target detection processing section 213 tracking processing section 22 transmitter 23 circulator 24 monopulse comparator 241 Σ signal generation Part 242 Δ Signal Generation Part 25 Antenna 251 Antenna Element 252 Antenna Element 253 First Antenna Group 254 Second Antenna Group 255 First Area 256 Second Area 26 Receiver 3 Control Device 4 Attitude Control Device 5 Propulsion Device 70 _N-1 , 70 _N , 70 _N+1 , 70 _N+2 , 70 _N+3 Reflector distribution pattern 8 Ship (target)
80 _N , 80 _N+1 , 80 _N+2 target reflection pattern 81 ship radar coverage 9 sea surface (clutter source surface)
90 _N+2 , 90 _N+3 clutter reflection pattern A _A , A _B grazing angle D _A , _{D B} detection distance G _A , GB, G _{1 Σ} , G 1 _Δ , G 2 _Σ , G _{2 Δ} , G 3 _Σ , G 3 _Δ , G _{4 Σ} , G _4Δ , G _5Σ , G _5Δ Graph H _A , HB Altitude _{R 1} , R ₂ , R ₃ , R _N-1 , R _N , R _N+1 , R _N+2 , R _N+3 Range Cells TH1, TH2, TH3, TH4 Threshold α Range Resolution adjustment value ΔR Range resolution

Claims (14)

A radar apparatus mounted on a projectile for detecting a target to guide the projectile to the target above a clutter source surface,
an antenna that transmits a radar wave from above the target and receives a reflected wave for a first period that is included in at least the radar reflected wave reflected by the target;
A signal processing device that detects the target based on the time from transmitting the radar wave to receiving the reflected wave for the first period and the reflected wave for the first period;
The radar apparatus, wherein a range of irradiation angles irradiated with the transmitted radar waves includes a normal line direction of the clutter source surface. In the radar device according to claim 1,
The first time period reflected wave includes a first time when a first time period has passed since the radar wave was transmitted, and a second time when a first time interval has passed since the first time. is the portion received in the first time period during the radar installation. In the radar device according to claim 2,
The antenna further receives a 0th period reflected wave different from the 1st period reflected wave, which is included in the radar reflected wave;
The 0th period reflected wave is received in the 0th period between the first time and the 0th time before the first time interval elapses by the first time, among the radar reflected waves. is the part
The signal processing device detects the target further based on the time from the transmission of the radar wave to the reception of the 0th period reflected wave and the 0th period reflected wave. In the radar device according to claim 3,
The antenna is
a first antenna group arranged in a first region;
A second antenna group arranged in a second area different from the first area,
The first antenna group receives a first area reflected wave reaching the first area among the radar reflected waves,
The second antenna group receives a second area reflected wave reaching the second area among the radar reflected waves,
The radar device
A monopulse comparator that generates a Σ signal representing the sum of the first area reflected wave and the second area reflected wave and a Δ signal representing the difference between the first area reflected wave and the second area reflected wave,
The signal processing device detects the target further based on the Σ signal and the Δ signal. Radar device. In the radar device according to claim 4,
The signal processing device is
A first period representing the sum of a first period first area reflected wave received by the first antenna group and a first period second area reflected wave received by the second antenna group among the first period reflected waves. a period Σ signal;
a first period Δ signal representing the difference between the first period first area reflected wave and the first period second area reflected wave;
The 0th period represents the sum of the 0th period first area reflected wave received by the first antenna group and the 0th period second area reflected wave received by the second antenna group among the 0th period reflected waves. generates a period Σ signal and
The signal processing device is
a first period Σ received power representing the received power of the first period Σ signal;
a first period Δ received power representing the received power of the first period Δ signal;
A radar apparatus that detects the target further based on the 0th period Σ received power representing the received power of the 0th period Σ signal. In the radar device according to claim 5,
The signal processing device is
A first power difference obtained by subtracting a predetermined noise level from the first period Σ received power is greater than a first threshold, and
A second power difference obtained by subtracting the 0th period Σ received power from the first period Σ received power is smaller than a second threshold, and
When a third power difference obtained by subtracting Δ received power in the first period from Σ received power in the first period is larger than a third threshold value, the radar wave is reflected as a reflected wave in the first period, and the target is detected in the space. determined to have detected
The first threshold is set based on the noise level and a target received power representing the received power of a portion of the radar reflected wave derived from the target,
The second threshold is set based on the clutter received power representing the received power of the part of the radar reflected wave derived from the clutter source surface and the target received power,
The radar device, wherein the third threshold is set based on the target received power. In the radar device according to claim 5,
The antenna receives a reflected wave of a second period, which is different from the reflected wave of the 0th period and the reflected wave of the first period and which is included in the reflected radar wave and is the reflected wave of the radar wave reflected at least on the surface of the clutter source. further receive during a second period between time 2 and a third time when the first time interval has elapsed from the second time;
The signal processing device is
A second period representing the sum of a second period first area reflected wave received by the first antenna group and a second period second area reflected wave received by the second antenna group among the second period reflected waves. further generating a period Σ signal,
The signal processing device is
A first power difference obtained by subtracting a predetermined noise level from the first period Σ received power is greater than a first threshold, and
A second power difference obtained by subtracting the 0th period Σ received power from the first period Σ received power is smaller than a second threshold, and
A third power difference obtained by subtracting the first period Δ received power from the first period Σ received power is greater than a third threshold, and
When a fourth power difference obtained by subtracting the first period Σ received power from the second period Σ received power representing the received power of the second period Σ signal is greater than a fourth threshold, the radar wave is reflected for the first period. Determining that the target is detected in the space reflected as a wave,
The first threshold is set based on the noise level and a target received power representing the received power of a portion of the radar reflected wave derived from the target,
The second threshold is set based on the clutter received power representing the received power of the part of the radar reflected wave derived from the clutter source surface and the target received power,
The third threshold is set based on the target received power,
The fourth threshold is based on the clutter received power and the target received power when the distance from the antenna to the clutter source surface is equal to the distance that the radar wave propagates by the third time. Configured radar equipment. In the radar device according to claim 5,
The antenna receives a second period reflected wave of the radar wave reflected at least by the target, which is different from the 0th period reflected wave and the first period reflected wave, and is included in the radar reflected wave, at the second time. further receive during a second period between a subsequent third time and a fourth time when the first time interval has elapsed from the third time;
The antenna has a third antenna which is different from the 0th period reflected wave, the 1st period reflected wave, and the 2nd period reflected wave, and which is different from the 0th period reflected wave, the 1st period reflected wave, and the 2nd period reflected wave. further receiving a period reflected wave in a third period between the fourth time and a fifth time when the first time interval has elapsed from the fourth time;
The signal processing device is
A second period representing the sum of a second period first area reflected wave received by the first antenna group and a second period second area reflected wave received by the second antenna group among the second period reflected waves. a period Σ signal;
A third period representing the sum of a third period first area reflected wave received by the first antenna group and a third period second area reflected wave received by the second antenna group among the third period reflected waves. and further generating a period Σ signal,
The signal processing device is
A first power difference obtained by subtracting a predetermined noise level from the first period Σ received power is greater than a first threshold, and
A second power difference obtained by subtracting the 0th period Σ received power from the first period Σ received power is smaller than a second threshold, and
A third power difference obtained by subtracting the first period Δ received power from the first period Σ received power is greater than a third threshold, and
when a fourth power difference obtained by subtracting the second period Σ received power representing the received power of the second period Σ signal from the third period Σ received power representing the received power of the third period Σ signal is greater than a fourth threshold; , determining that the target is detected in the space where the radar wave is reflected as the second period reflected wave;
The first threshold is set based on the noise level and a target received power representing the received power of a portion of the radar reflected wave derived from the target,
The second threshold is set based on the clutter received power representing the received power of the part of the radar reflected wave derived from the clutter source surface and the target received power,
The third threshold is set based on the target received power,
The fourth threshold is based on the clutter received power and the target received power when the distance from the antenna to the clutter source surface is equal to the distance that the radar wave propagates by the third time. Configured radar equipment. In the radar device according to claim 7 or 8,
The signal processing device is
reducing the first time interval by a second time interval when the fourth power difference is less than a fourth threshold;
A radar device that repeats the detection process using the reduced first time interval. In the radar device according to any one of claims 6 to 9,
The signal processing device is
delaying the first time by the first time interval when the second power difference is smaller than the first threshold;
A radar device that repeats the detection process using the delayed first time. In the radar device according to any one of claims 6 to 10,
The signal processing device is
finely adjusting the irradiation angle range when the second power difference is greater than a second threshold;
A radar device that repeats the detection process based on the Σ signal and the Δ signal obtained by transmitting the radar wave in the range of the finely adjusted irradiation angle. In the radar device according to any one of claims 6 to 11,
The signal processing device is
finely adjusting the irradiation angle range when the second power difference is smaller than a third threshold;
A radar device that repeats the detection process based on the Σ signal and the Δ signal obtained by transmitting the radar wave in the range of the finely adjusted irradiation angle. A radar device according to any one of claims 1 to 12;
a control device that generates an attitude control signal based on a signal that the radar device outputs based on detection of the target;
an attitude control device that controls the attitude of the flying body so that the flying body moves toward the target based on the attitude control signal. A guidance program for realizing a process of guiding a projectile to a target above the surface of the clutter source, by executing the processing by the arithmetic device,
transmitting a radar wave from above the target and receiving a reflected wave for a first period included in at least the radar reflected wave reflected by the target;
detecting the target based on the time from transmitting the radar wave to receiving the reflected wave for the first period and the reflected wave for the first period;
The guidance program, wherein the range of irradiation angles at which the transmitted radar waves are irradiated includes a normal direction of the clutter source surface.

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