JP2001263994A - Lazer missile seeker device adapting cdl - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a missile seeker device to detect wind generated by a helicopter hiding out in a recess of a mountain by a coherent Doppler LIDAR system and generate an induction signal induced thereto. SOLUTION: A missile seeker device comprises laser irradiation parts 16, 11, 12, and 13 to perform irradiation with laser, laser receiving parts 13, 12, 15, and 17 to receive a reflection wave by pointing to the same direction as that of an optical axis of irradiation and output an output signal based on the reflection wave, a detector 17 to detect the presence of an object based on a detected Doppler frequency by varying a frequency band by discriminating the frequencies of output signals from the laser receiving parts, and a LIDAR signal processing part 18 to output an induction signal related to the flying direction of a missile based on the detecting result. A turbulent flow of the atmosphere by a helicopter is detected by a coherent Doppler LIDAR system to induce a flying object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a missile seeker, and more particularly, to a missile seeker using a CDL (coherent Doppler lidar (light detection ranging)).

[0002]

2. Description of the Related Art Recently, a high level of ground-to-air guided missile control method has been demanded, and the ability to cope with an object which cannot be directly captured by a conventional laser is required.

In the conventional missile seeker, if the irradiated laser catches the target and if it can be detected by the seeker as a reflected wave from the target, the position of the target is determined, and this is compared with the current position with the current flying object to infer. By generating the guidance signal, the flying object can be guided to the target. Therefore, it is important that the target is always directly irradiated with the laser, and the target is searched based on the reflected wave of the directly irradiated laser.

[0004]

However, a laser emitted by a seeker for guiding a flying object cannot always directly irradiate an object, for example, a helicopter hidden in a mountain shade or the like. Can not do it. For this reason, since the reflected wave of the laser cannot be obtained,
There is a problem that the flying object cannot be guided to the helicopter hidden in the San'in and the like.

The present invention provides a guidance signal to an object which cannot be directly irradiated with a laser as in this case, detects a wind generated by a target in initial guidance, and controls a helicopter rotor at a short distance. It is an object of the present invention to provide a missile seeker device capable of detecting and guiding to a helicopter in an invisible san'in, with high accuracy.

[0006]

According to the present invention, there is provided a laser irradiating means for irradiating a laser; and a reflected wave of the laser directed in the same direction as an optical axis of the laser irradiating means. And a laser receiving means for outputting an output signal based on the received signal; and detecting the presence of the target based on the Doppler frequency detected by discriminating the frequency of the output signal from the laser receiving means and changing the frequency band. Detecting means; and signal processing means for outputting a guidance signal relating to the missile's flight direction based on the detection result of the detecting means.
And a missile seeker device mounted on the missile.

According to the present invention, the frequency of an output signal from the obtained reflected wave is discriminated, and the frequency band is made different, instead of knowing the target from the reflected wave of the laser irradiated as in the conventional apparatus. it allows to detect the Doppler frequency as a shift component f _d of the frequency. Thus, the missile seeker device detects, for example, wind generated by a rotor of a helicopter or movement of the rotor itself, and generates a guidance signal of a flying object according to the detection result. As a result, for example, it is possible to track and guide a helicopter that cannot be detected in the past because it is hidden behind a mountain shade.

The present invention also provides a laser irradiating means for irradiating a laser after modulating the laser with a modulator, and directing the reflected wave of the laser in the same direction as the optical axis of the laser irradiating means so as to make the divergence angle of the laser constant. Laser receiving means for receiving an optical signal using an optical mixer capable of removing the frequency of a CW laser serving as an oscillation source of a pulse laser from the frequency of the reflected wave, and converting the optical signal into an electric signal; Based on the Doppler frequency detected by discriminating the frequency of the electric signal from the laser receiving means and changing the frequency band,
A missile seeker device using a heterodyne method, comprising: a detecting means for detecting the presence of an object; and a signal processing means for outputting a guidance signal relating to a flight direction of the missile based on a detection result of the detecting means. It is.

Further, according to the present invention, the laser receiving means has a four-division detecting element, and can perform a monopulse angle measurement for outputting an induction signal with only one pulse by an output difference between the elements. Missile seeker device.

Further, according to the present invention, the signal processing means calculates a distance to a target based on a time difference between a laser emission time and a Doppler reception time based on a detection result of the detection means, and based on the calculated distance, relates to a flight direction of the missile. 3. The missile seeker device according to claim 1, further comprising signal processing means for outputting a guidance signal.

Further, according to the present invention, the signal processing means calculates a distance to a target based on a time difference between a laser emission time and a Doppler reception time based on a detection result of the detection means. An inductive signal is output according to the detection result in the first frequency width for detection, and when the distance to the target approaches a predetermined value or less, a second signal different from the first frequency width is detected in order to detect a helicopter rotor. The missile seeker device according to claim 1, wherein the missile seeker device outputs a guidance signal based on the detection result in the frequency width.

Further, in the present invention, the laser irradiation means may be a CW laser.
Irradiating a laser obtained by modulating the laser, further the laser receiving means and the detecting means and the signal processing means, a signal for mixing and detecting the reflected wave of the laser and the CW laser, the rotor wind or the rotor 3. The missile seeker device according to claim 1, wherein an output difference from a signal obtained by scanning is obtained, and an induction signal is output based on the output difference.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a missile seeker according to the present invention. In this figure, a master CW laser 16 connected to a controller 10 that controls the entire operation is connected to a pulse laser 11 that is a slave, connected to an optical duplexer 12, connected to an optical system 13, and connected to an atmospheric Doppler. 14 is irradiated with a laser. Further, the CW laser 16 for transmitting the local oscillation light f0
Are connected to the optical mixer 15, connected to the detector 17, and connected to the LIDAR signal processing unit 18.

In such a configuration, the missile seeker of the present invention operates as follows. That is, under the operation control of the control unit 10, the CW laser 16 which is the master
Laser as the seed light f ₀ generated from the laser f synthesized by pulsed laser 11 is the slave
_The signal is modulated as ₀ + f _IF and supplied to the optical duplexer 12. Thereafter, the atmospheric Doppler 14 passes through an optical system 13 having a mechanism (not shown) capable of directing the optical axis at an arbitrary angle.
Radiated to The emitted reflected wave of the laser is again received by the laser receiver included in the optical system 13 and directed in the same direction as the optical axis at the time of irradiation while keeping the divergence angle of the laser constant. Is supplied again. Then, the reflected wave of this laser is supplied to the optical mixer 15, from which the frequency of the CW laser which is the source of the pulse laser is removed. Furthermore, the optical signal supplied from the optical mixer 15 in the detector 17 is converted into an electric signal, a Doppler frequency component f _d by varying the frequency band by discriminates the frequency is detected. On the basis of this component, for example, a wind generated by a rotor of a helicopter or a movement itself of the rotor, which cannot be detected conventionally, are detected.

FIG. 2 is a diagram showing the relationship between the missile seeker according to the present invention, the surrounding terrain, and the wind generated by the target rotor. FIG. 3 is a diagram showing the rotor targeted by the missile seeker according to the present invention. FIG. 4 is a diagram showing a turbulence model in which turbulence occurs.
FIG. 5 is a diagram showing a laser transmission / reception line model of a missile seeker according to the present invention. FIGS. 5A and 5B show, in a missile seeker according to the present invention, (a) a reception signal in which a helicopter rotor appears, and (b) a reception signal in which nothing appears. (C) is a graph showing a received signal in which the helicopter rotor wind appears,
FIG. 6 is a graph showing each signal in the block diagram of the missile seeker according to the present invention, FIG. 7 is a diagram showing a schematic relationship between the missile seeker according to the present invention and the missile, and FIG. FIG. 9 is a block diagram showing a configuration of a homodyne type missile seeker according to the present invention, showing a table showing atmospheric turbulence detection between a CDL and a radio wave radar applied to such a missile seeker.

In FIG. 2, the seeker mounted on the installation device C or the missile M does not directly catch the helicopter H present in the shadow of the mountain by the irradiating laser, but the wind generated by the rotating rotor and the rotor itself. The frequency component of the Doppler frequency based on the Doppler effect caused by the movement is detected, and thereby, the presence of the helicopter H is detected, and the guidance signal is generated and guided to guide the flying object M.

FIG. 3 shows a turbulent sphere model generated by the rotor. For example, assuming an average velocity of about 4 m / s in the laser transmission / reception direction of a 60 m hemisphere, the wind speed ν near the center of the helicopter is ν = (T / 2tσR ² )
It is represented by ^1/2 . At this time, if ν is the wind speed near the center of the edge, T: the lift of the helicopter is 10,000 k
g, ρ: air density is 0.125 kgs ² / m ⁴ , R: rotor speed of the helicopter is 7.5 m, wind speed ν = 1
5 (m / s).

Still referring to FIG. 4, when the laser captures a turbulent sphere generated by the helicopter rotor, the received power Pr [W] can be assumed as follows. That is, the laser power of the laser to be irradiated is P ₀ [W], the distance to the turbulent sphere is r, the cross-sectional area of the laser is A [m ² ], and an obstacle such as a mountain is I = P0 · β · (C · π /
2) When e- ^αr , reception power Pr = I · Ω ·
e- ^αr [W]. Therefore,
By using this relationship, it is possible to calculate the degree of the wind based on the generated rotor or the degree of movement of the rotor itself.

According to FIG. 5, the frequency characteristics of the signal obtained by the detector 17 are as follows: (a) when the rotor of the helicopter H is detected; (b) when there is no wind from the rotor or the rotor; The cases where there is only the wind from the rotor and the rotor is not directly captured are shown. Therefore, by discriminating the frequency characteristics of the signal obtained by the detector 17 and verifying its Doppler frequency component, the wind generated by the helicopter rotor and the movement of the rotor itself can be obtained even if the helicopter body itself is not captured. If captured, the presence of a helicopter can be accurately predicted.

FIG. 6 is a graph showing the signal components at this time. Here, when the pulse width of heterodyne detection is t and the pulse period is T, the signal components obtained as reflected waves include: it can be seen that contain shift component f _d as a Doppler frequency.

FIG. 7 is a diagram schematically illustrating the relationship between the missile seeker according to the present invention and the missile M, which is a flying object. The guidance signal from the missile seeker 21 is transmitted via the steering unit 22. To the main wing 23 and further to the propulsion unit 24
It can be seen that the operation of the missile seeker according to the present invention provides appropriate flight direction control.

Attention is paid to the function of the LIDAR signal processing unit 18 at this time. One of the methods is to provide a four-divided detection element in a laser receiver, and to cause a flying object to fly due to a difference in output of each element. The direction can be determined, and a monopulse angle measurement that outputs a guide signal with only one pulse can be performed.

The LIDAR signal processing unit 18 calculates the distance to the target from the time difference between the laser emission time and the Doppler time based on the electric signal supplied from the detector 17, and based on the distance, calculates the guidance signal. It is preferred to determine. Further, after the missile is fired, an induction signal is output according to the detection result at the first frequency width to detect the wind, and when the distance to the target approaches a predetermined value or less, the first signal is output to detect the rotor of the helicopter. Second different from frequency width
It is possible to switch to the frequency width and output a guidance signal based on the detection result at this width, and thereby efficiently guide the flying object targeting the helicopter.

In FIG. 9, it is pointed out that it is possible to detect a helicopter rotor or the like using the coherent Doppler lider of the present invention not only by the heterodyne method of FIG. 1 but also by the homodyne method. deep. In this figure, in the homodyne system, a plurality of lasers are not required unlike the heterodyne system, and by adding the modulator 19 only to the CW laser 16, it is possible to perform almost the same processing as in the heterodyne system. I understand. Strictly speaking, the peak power of the echo of the CW laser is smaller than that of the pulse laser. Therefore, it is necessary to focus the beam and put the echo into a single element. In order to gain a search area, it is necessary to scan the irradiation and reception optical axes with little overlap. Therefore, the homodyne method has a simple device configuration, but has a detection capability (detection distance or scanning rate).
Is inferior to the heterodyne system, and it is difficult to output the distance.

In FIG. 8, CDL (coherent
Doppler lidar) system and radio radar system
A comparison for helicopter atmospheric turbulence detection is shown in the table. At this time, regarding the detection resolution of the atmospheric turbulence velocity,
Compared to the CDL indicating fd = 8 MHz, which facilitates separation, the radio wave radar can obtain only fd = 533 Hz, indicating that separation is extremely difficult. Regarding the degree of backscattering, the radio wave radar does not scatter unless it is raindrop-sized particles, as compared with the fact that CDL scatters well on standby suspended particles. Is not obtained as well as CDL. Finally, regarding the spatial pointing resolution, the CDL shows a high value of about 0.2 mrad, whereas the radio wave radar has about 2/170
°, and you can see that there is also a big difference in beam width resolution.

Therefore, it is shown that there is a great difference between the two processing capacities in detecting the atmospheric turbulence of the helicopter.

It should be noted that the above description of the embodiments facilitates the manufacture and use of the present invention to those skilled in the art, and these various modifications may be made without departing from the invention. It is possible by a trader. Thus, the present invention provides
The present invention is not limited to the described embodiments, but covers a wide range of forms corresponding to this principle and novel features.

[0029]

As described above, according to the present invention, coherent
By using a Doppler lidar type missile seeker device, it is possible to detect turbulence in a helicopter. , It is possible to provide a missile seeker device that can guide the flying object to the helicopter.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a missile seeker according to the present invention.

FIG. 2 is a diagram showing a relationship between a missile seeker according to the present invention, surrounding terrain, and wind generated by a target rotor.

FIG. 3 is a diagram showing a turbulence model generated by a rotor targeted by a missile seeker according to the present invention.

FIG. 4 is a diagram showing a laser transmission / reception line model of a missile seeker according to the present invention.

FIG. 5 shows a missile seeker according to the present invention;
7A is a graph showing a received signal in which a helicopter rotor appears, FIG. 7B is a graph showing a received signal in which nothing appears, and FIG. 7C is a graph showing a received signal in which a helicopter rotor wind appears.

FIG. 6 is a graph showing each signal in the block diagram of the missile seeker according to the present invention.

FIG. 7 is a diagram showing a schematic relationship between a missile seeker and a missile according to the present invention.

FIG. 8 is a CD applied to the missile seeker according to the present invention.
6 is a table showing detection of atmospheric turbulence between L and a radio radar.

FIG. 9 is a block diagram showing a configuration of a homodyne type missile seeker according to the present invention.

[Explanation of symbols]

 M: Missile device main body 10: Control unit 11: Pulse laser 12: Optical duplexer 13: Optical system 14: Atmospheric Doppler 15: Optical mixer 16: CW laser 17: Detector 18: LIDAR signal processing unit 21: Seeker device 22: Steering Part 23… Main wing 24… Propulsion part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C014 DA08 DB03 DC01 DD11 5J084 AA05 AA07 AB03 AC02 AC06 AD03 AD04 BA22 BA23 BA37 BA43 BA44 DA01 EA07 EA27 FA03

Claims (6)

[Claims] A laser irradiating means for irradiating a laser; a laser receiving means for receiving a reflected wave of the laser in the same direction as an optical axis of the laser irradiating means and outputting an output signal based on the reflected wave; Detecting means for detecting the presence of an object based on a Doppler frequency detected by discriminating a frequency of an output signal from the laser receiving means and changing a frequency band; and a missile based on a detection result of the detecting means. Signal processing means for outputting a guidance signal related to the flight direction of the missile; and a missile seeker device mounted on the missile. A laser irradiating means for irradiating the laser after modulating the laser with a modulating unit; and directing the laser beam in the same direction as the optical axis of the laser irradiating means so as to maintain the divergence angle of the reflected wave of the laser constant. Laser receiving means for receiving an optical signal using an optical mixer capable of removing the frequency of a CW laser serving as an oscillation source of a pulse laser from the frequency of the reflected wave, and converting the optical signal into an electric signal; Detecting means for detecting the presence of an object based on the Doppler frequency detected by discriminating the frequency of the electric signal from the apparatus and changing the frequency band; and a guiding signal regarding the flight direction of the missile based on the detection result of the detecting means. A signal processing means for outputting a signal; and a missile seeker device using a heterodyne method. 3. The laser receiving means according to claim 1, wherein said laser receiving means has a quadrant detecting element, and can perform a monopulse angle measurement for outputting an induction signal with only one pulse according to an output difference between the elements.
And 2. The missile seeker device according to 2. 4. The signal processing means calculates a distance to a target based on a time difference between a laser emission time and a Doppler reception time on the basis of a detection result of the detection means, and generates a guidance signal relating to a flight direction of the missile based on the distance. 3. The missile seeker device according to claim 1, further comprising signal processing means for outputting. 5. The signal processing means calculates a distance to a target based on a time difference between a laser emission time and a Doppler reception time based on a detection result of the detection means, and detects a wind immediately after the missile is fired. An inductive signal is output in accordance with the detection result in the first frequency width, and when the distance to the target approaches a predetermined value or less, to a second frequency width different from the first frequency width to detect a helicopter rotor. 3. The missile seeker device according to claim 1, wherein a guidance signal is output based on the detection result at the switching width. 4. 6. The laser irradiating means irradiates a laser obtained by modulating a CW laser, and the laser receiving means, the detecting means and the signal processing means mix a reflected wave of the laser with the CW laser. To obtain the output difference between the signal to be detected and the signal obtained by scanning the rotor wind or the rotor,
3. The missile seeker device according to claim 1, wherein an induction signal is output based on the output difference.