JP2782580B2 - Flying object guidance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guidance device for a flying object guided by an image guidance system.

[0002]

2. Description of the Related Art FIG. 8 is a diagram showing a configuration of a flying object guided by a conventional image guiding method. Reference numeral 1 denotes a radome or optical dome (hereinafter referred to as a dome) which has a low aerodynamic resistance and transmits a signal medium for target detection such as light or radio waves.
Reference numeral 2 denotes an optical lens for condensing the signal medium transmitted through the dome 1 on a detector, and reference numeral 3 denotes an image capable of forming an image in a range in a predetermined direction.
The dimension detector, 4 is a dewar for cooling the two-dimensional detector 3, 5 is a shell of the flying object, 6 is an inertial sensor, 48 is a mechanical device for stabilizing the visual field of the two-dimensional detector 3 in inertial space. 2 shows a two-axis gimbal mechanism.

FIG. 9 is a block diagram showing the function and configuration of a conventional guidance device. Reference numeral 7 denotes an A / D converter for converting an output image signal of the two-dimensional detector 3 into a digital signal. Reference numeral 9 denotes a target extraction processing circuit for extracting a target from the output image signal.
Is a target tracking processing circuit that tracks the target selected by the target extraction processing circuit 9, and 49 is a command for stabilizing the two-dimensional detector 3 on the inertial space based on the attitude angle signal and the tracking error signal and directing the two-dimensional detector 3 toward the target. Is provided to the torquer of the gimbal mechanism 48.

FIG. 10 is a diagram showing a definition of an angle in an image obtained by a conventional guidance device. 25 is a flying object, 26
Is the field of view of the two-dimensional detector, 27 is the inertial reference coordinate axis, 28 is the machine axis, 29 is the target, 30 is the attitude angle, 52 is the gimbal center, 53 is the gimbal angle, 54 is the tracking error angle, and 55 is the gimbal with respect to the inertial reference coordinate axis. Indicates an angle.

FIG. 11 is a control block diagram of a conventional guidance device. 3t is the accumulation time of the two-dimensional detector, 6d is the attitude angle detection of the inertial sensor 6, and 8t is the target extraction processing circuit 9.
And the signal processing time of the image processor constituted by the target tracking processing circuit 10, 30 is the attitude angle, 32 is the viewing angle, 3
3 indicates integration, 34 indicates an induced signal filter, 48d indicates gimbal angle detection, and 56 indicates homing head gain.

[0006] The conventional guidance device is configured as described above,
In FIG. 8, when the attitude angle of the flying body 25 changes due to the movement of the aircraft and the movement of the flying body 25, the amount of the change is detected by the inertial sensor 6, and the visual field of the two-dimensional detector 3 is always spatially the same. The gimbal mechanism 48 is driven by an amount corresponding to the change in the attitude angle so as to face the direction. In FIG. 9, 2
The image signal detected by the dimension detector 3 is subjected to a target tracking process by a target extraction processing circuit 9 and a target tracking processing circuit 10 to generate an induced signal 24 proportional to the tracking error and to generate a tracking error angle signal 22. A feedback 51 is sent to the space stabilization processing circuit 49, and a swing command 51 is sent to the torquer of the gimbal mechanism 48 so that the two-dimensional detector 3 always tracks the target.

In FIGS. 10 and 11, in the case of space stabilization, the inertia reference coordinate axis 2
In order to direct the gimbal angle 55 to the gimbal angle 55 in a certain direction, the gimbal angle 53
Is controlling. In the case of tracking, the gimbal direction with respect to the inertia reference coordinate axis 27 is kept constant, and the above-mentioned spatial stabilization is maintained.
The gimbal swing angle command 51 is given by the space stabilization processing circuit 49 so as to control the gimbal angle 55 with respect to the inertial reference coordinate axis 27 by the tracking error angle signal 22 corresponding to the homing head gain 56.

[0008]

The guiding device for a flying object guided by the conventional image guiding system is constructed as described above, and is provided with a space through a complicated mechanical movable part such as a gimbal mechanism 48. Since the stabilization is achieved, deterioration of the space stabilization performance due to bearing friction is inevitable. Furthermore, it has become a heavy burden in reducing the size, cost, and reliability of the guidance device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has a configuration in which a sensor is fixed to a flying object, and can detect a visual angular velocity required for guiding the flying object. An object of the present invention is to provide a small and low-priced guidance device and obtain high reliability without having a mechanically movable part such as the gimbal mechanism 48.

[0010]

A guidance device according to the present invention comprises a two-dimensional detector fixed to an airframe and capable of forming an image in a predetermined direction, and a target tracking point based on an output image signal of the detector. An image processor that detects the angle, a differential calculator, an inertial sensor that detects the attitude angular velocity of the flying object, and a target tracking point angle differential signal and the attitude angular velocity signal of the flying object detected by the inertial sensor are added It comprises an adder, a gain adjuster, and a phase adjuster.

Also, as a phase adjuster, the detection signal of the attitude angle of the flying object by the inertial sensor is set to one half of the charge accumulation time of the two-dimensional detector and the tracking point angle outputted by the image processor after the charge accumulation. A delay circuit is added to provide a delay equivalent to a time obtained by subtracting the processing time of the inertial sensor from the time until the differential operation unit differentiates the signal and outputs the tracking point angle differential signal.

Further, a circuit for controlling the delay time of the delay circuit according to the target tracking point angle is added.

Further, the distortion data of the optical lens is stored in advance in a memory in the gain adjuster as a correction value.

Further, the apparatus further comprises a temperature monitor for measuring the temperature of the optical lens, and a memory in the gain adjuster includes:
The change in the focal length of the optical lens due to the temperature change is stored in advance in the form of an angle conversion correction value.

[0015]

The guidance device according to the present invention calculates the target tracking point angle from the image signal detected by the two-dimensional detector at each frame rate, and differentiates the target tracking point angle from the target tracking point angle to the attitude angular velocity signal of the flying object. The signal to which a predetermined gain and a time delay have been given by the adjuster and the gain adjuster is added by the adder, and the result is output as an induced signal.

Also, since a phase difference occurs between the attitude angular velocity signal of the flying object detected by the inertial sensor and the tracking point angle differential signal obtained from the image signal detected by the two-dimensional detector, the same as the image detection. In order to be able to add the attitude angular velocity at the time, the inertial sensor processing is performed by calculating the attitude angular velocity signal from the sum of the processing time until the tracking point angle differential signal is output after the charge accumulation time of the two-dimensional detector and the charge accumulation time of the two-dimensional detector. Delay by subtracting time.

Further, in the case where the electric charge is stored in the two-dimensional detector in a type in which a time difference is generated between pixels, the time difference varies depending on the position (angle from the machine axis) of the area to be processed. The delay time is controlled according to the angle from the center to the target tracking point.

Further, distortion occurs in the optical lens, and the actual angle and the angle on the image detected by the two-dimensional detector do not have a linear relationship in the entire field of view. When a target angle is detected on an image, a correction value for correcting how many times the angle corresponds to an actual angle is stored in a memory, and the correction value is read from the memory in accordance with the target tracking point angle. , Correction is applied to the output of the tracking point angle.

Furthermore, since the refractive index of the optical lens changes depending on the ambient temperature, which changes the focal length equivalently, the change in the focal length with respect to the temperature and the scale factor to be converted with respect to the focal length are investigated in advance. By storing this in a memory, the temperature of the optical lens is monitored, and an appropriate gain is set according to the temperature.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a part of the structure of a guidance device according to the present invention, which does not have a gimbal structure like the conventional guidance device shown in FIG. Is fixed to.

FIG. 2 is a block diagram showing an example of the function and configuration of the guidance device of the present invention. 7 is an A / D converter for converting the output image signal of the two-dimensional detector 3 into a digital signal;
Reference numeral 8 denotes an image processor for processing the digital image signal obtained by the A / D converter 7, reference numeral 9 denotes a target extraction processing circuit for extracting a target from the image signal, and reference numeral 10 denotes an image processor. A target tracking processing circuit configured to track the extracted target and output a tracking point angle, 11 is a gain adjuster for adjusting a gain with respect to the tracking point angle signal output from the target tracking processing circuit 10, and 12 is an inertial sensor 6 A phase adjuster for adjusting the phase of the attitude angle signal of the flying object detected in step 13; a differential calculator 13 for differentiating the tracking point angle signal; 14 a tracking point angle differential signal and attitude angular velocity signal output from the differential calculator 13 , A delay circuit for providing a delay time to the attitude angular velocity signal, and 16 for a tracking point angle signal output from the target tracking processing circuit 10. Depending A delay time control circuit for controlling the delay time of the extension circuit 15, 17 is provided in the gain adjuster 11, a gain for adjusting the scale factor of the tracking point angle output from the target tracking processing circuit 10, and 18 is provided for the gain adjuster 11. A distortion correction memory configured to store a correction value of a gain from the distortion characteristic of the optical lens 2. A temperature 19 configured to the gain adjuster 11 stores a correction value for correcting a focal length variation due to a temperature of the optical lens 2. A correction memory, 20 is an optical lens temperature monitor for measuring the temperature of the optical lens 2, 21 is a tracking point angle signal detected by the image processor 8, 22 is a tracking point angle differential signal obtained by differentiating the tracking point angle signal 21, and 23 is The attitude angular velocity 24 detected by the inertial sensor 6 indicates a guidance signal.

FIG. 3 is a diagram showing the definition of an angle in an image obtained by the two-dimensional detector 3, wherein 25 is a flying object,
26 is the field of view of the two-dimensional detector 3, 27 is the inertial reference coordinate axis,
28 is the center (axis) of the visual field, 29 is the target, 30 is the detected attitude angle, 31 is the target angle in the visual field, and 32 is the visual line angle. FIG. 4 is a control block diagram corresponding to the configuration of FIG. 2 as a representative. Reference numeral 33 denotes an integration, and 34 denotes an induced signal filter. FIG. 5 is a diagram showing the timing of charge accumulation and charge transfer of a type of detector in which charge accumulation is performed sequentially line by line as an example of the two-dimensional detector 3. The charge accumulation time for each horizontal line, 36 indicates the charge transfer time for each horizontal line of the two-dimensional detector 3.

FIG. 6 is a diagram showing the relationship between the focal length of the optical lens 2, the incident angle, and the image height. 37 is the optical lens 2
Are the incident angles θ of the target 29 when the focal length is f, 39 are the image heights y of the two-dimensional detector 3 of the target 29 when the focal length is f, and 40 are the focal lengths f that vary with temperature. ', 41 are the position of the optical lens 2 when the focal length is f', 42 is the incident angle θ 'of the target 29 when the focal length is f', and 43 is the two-dimensional detector of the target 29 when the focal length is f ' 3 shows the image height y ′. 7 is a graph showing the relationship between the incident angle 38 and the image height 39, 44 is a graph of y = θ, 45 is a graph of y = fSinθ, 46 is a graph showing distortion characteristics of the optical system, and 47 is y. The graph of '= f'Sinθ' is shown.

In the guiding device configured as described above, the output image signal of the two-dimensional detector 3 is output to the A / D converter 7.
Are converted into digital signals, and the target tracking point angle signal 21 is detected by the target extraction processing circuit 9 and the target tracking processing circuit 10 of the image processor 8. The gain adjuster 11 applies a predetermined gain to the tracking point angle signal 21 so as to match the attitude angular velocity signal with the amplitude level, and differentiates it with the differential calculator 13 to obtain a tracking point angle differential signal 22. On the other hand, the attitude angular velocity signal 23 detected by the inertial sensor 6 is
Is sent to the adder 14 after being given a predetermined delay time to match the time at which the image was acquired by the delay circuit 15 of
Tracking point angle differential signal 22 and attitude angular velocity signal 2 at the same time
3 are added to obtain the guidance signal 24. The guidance signal is output to an actuator provided on the aircraft of the flying vehicle 25 and used as a signal for controlling each part of the aircraft such as closing the wings of the aircraft.

In FIG. 3, the guidance signal of the flying object 25 is to determine the rate of change of the visual line angle 32, which is the angle of the target 29 with respect to the inertial reference coordinate axis 27. According to the method of the present invention, the axis 28 of the flying object 25 and the center of the visual field 26 of the two-dimensional detector 3 are matched. If the angle of the target 29 from the center of the visual field coincident with the machine axis 28 in the visual field 26 detected by the two-dimensional detector 3 is the tracking point angle 31, the sum of the attitude angle 30 and the tracking point angle 31 is represented by the visual line angle 32. Accordingly, by adding the attitude angular velocity signal 23 which is a differential value of the attitude angle 30 and the tracking point angle differential signal 22 obtained by differentiating the tracking point angle 31, the required rate of change of the visual line angle 32 is obtained. A certain guidance signal 24 can be obtained.

In the guidance of the flying object 25, the spatial stabilization means that the two-dimensional detector 3 is placed on the inertial space regardless of the fluctuation of the attitude angle 30 of the flying object 25 in order to accurately detect the visual angular velocity. This is done on the signal in the system of the present invention. Therefore, the tracking point angle differential signal 22 and the attitude angular velocity signal 23 to be added must be signals at the same time. In FIG. 4, the detection of the tracking point angle differential signal 22 takes time corresponding to the accumulation time of the two-dimensional detector 3, the signal processing time of the image processor 8, and the time constant of the differential calculator 13. A delay time is given to the attitude angular velocity signal 23 detected in 6 by the delay circuit 15 and the phases of the signals to be added are matched to achieve spatial stabilization.

Next, as shown in FIG. 5, when a two-dimensional detector of a type in which the timing of charge accumulation and data transfer in the two-dimensional detector 3 is different for each line is used, the upper end of the detector is used. The charge accumulation time is different between the charge accumulation time 35a of the pixel and the charge accumulation time 35b of the pixel at the lower end, and if only one type of delay time is given by the delay circuit 15, a phase adjustment error occurs. Therefore,
The tracking point angle signal 21 detected by the image processor 8 is transferred to the phase adjuster 12, and the delay time given by the delay circuit 15 by the delay time control circuit 16 is set to be proportional to, for example, the tracking point angle 21. Control.

Next, as a characteristic of the optical lens, the visual field 26
Becomes larger, distortion occurs in the peripheral portion. Therefore, as shown in FIG. 7, the relationship between the image height y39 and the incident angle θ38 is originally y = S
There is a case where the distortion characteristic 46 is shown instead of the relation 45 of inθ. In this case, when the detected image height y39 is converted into an angle, the amplitude scale factor varies depending on the size of the image height y39 (equivalent to the tracking point angle 21). θ = Ay ³ + By ² + Cy +
d), and the coefficients of the approximation formula or the results of approximation at each point are used as distortion correction data as the distortion correction memory 18.
Keep it in memory. Thereby, the distortion characteristic is corrected for the tracking point angle detected by the image processor 8 (in this dictionary, not the angle but the pixel or image height), and the true incident angle θ38
(Tracking point angle 21) can be detected. Although the approximation formula varies depending on the sensor and the optical lens, approximation of a cubic formula can provide sufficient approximation accuracy for correction.

Next, referring to FIG.
When the temperature fluctuates with respect to the position, the refractive index of the lens changes, so that the equivalent focal length is changed from f37 to f'40.
Changes to As a result, the image height of the target 29 on the two-dimensional detector 3 also changes from y39 to y'43, and an error occurs in the tracking point angle 22 detected by the image processor 8 (two-dimensional detection). The angle of incidence on the vessel 3 is also from θ38 to θ '
42, but since the distance to the target 29 is sufficiently larger than the focal length, it is considered that θ and θ ′ are substantially equal.) In FIG. 7, the relationship between the image height y39 before the temperature change does not occur and the incident angle 38 is as shown in a graph 45 of y = fSinθ, and when the temperature change occurs, y = f ′.
A graph 47 of Sin θ ′ is obtained. Therefore, an optical lens temperature monitor 20 is added to the optical lens 2, and data for correction conversion of y = fSinθ45 and y = f′Sinθ′47 for the temperature of the optical lens 2 is stored in the temperature correction memory 19 in advance. Then, a correction value is read from the temperature correction memory 19 of the gain adjuster 11 based on the detected temperature of the optical lens 2, and the gain 17 is corrected.
The tracking point angle 23 can be accurately detected even with respect to temperature fluctuation, thereby preventing deterioration of the space stabilization performance.

[0030]

According to the present invention, the flying object is moved to a target at a high speed, as described above.
The higher the relative speed between the flying object and the target, such as a target approaching the flying object at a high speed, the more effective the following effects are obtained.

Since the two-dimensional detector is fixed to the fuselage and has electronic processing to stabilize the space and generate a guidance signal without having a complicated mechanical movable part such as a gimbal mechanism, the flying object In addition to reducing the size and cost of the guidance device, the reliability is improved.

Further, by matching the phase of the target image signal detected by the two-dimensional detector with the phase of the body attitude angle signal detected by the inertial sensor, the spatial stabilization characteristics are improved.

Further, by controlling the delay time according to the tracking point angle in the delay circuit for adjusting the time,
No matter where in the wide field of view of the two-dimensional detector the target is detected,
Stable space stabilization characteristics can be obtained.

Further, distortion characteristics of the optical distortion generated around the visual field of the optical lens are stored in advance in a distortion correction memory, and the detected image height is corrected for distortion to detect a tracking point angle. As a result, the signal amplitude is accurately adjusted, and stable spatial stabilization characteristics can be obtained even when an optical lens having a wide field of view is used.

Further, an optical lens temperature monitor is added to the variation of the equivalent focal length of the optical lens due to the temperature change, and the gain of the temperature correction memory is corrected in accordance with the temperature of the optical lens, and the signal of the optical lens is monitored. By performing the amplitude adjustment, a stable space stabilizing characteristic can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a part of a guidance device according to the present invention.

FIG. 2 is a block diagram showing functions and configurations of the guidance device of the present invention.

FIG. 3 is a diagram showing a definition of an angle in an image obtained by a two-dimensional detector which is a component of the guidance device of the present invention.

FIG. 4 is a control block diagram of the guidance device of the present invention.

FIG. 5 is a diagram showing charge accumulation and charge transfer timing for one embodiment of a two-dimensional detector which is a component of the present invention.

FIG. 6 is a diagram showing a relationship between a focal length, an incident angle, and an image height of an optical lens which is a component of the present invention.

FIG. 7 is a diagram showing a relationship between an incident angle and an image height of an optical system which is a component of the present invention.

FIG. 8 is a sectional view showing a part of a conventional guidance device.

FIG. 9 is a block diagram showing functions and configurations of a conventional guidance device.

FIG. 10 is a diagram showing a definition of an angle in an image obtained by a conventional guidance device.

FIG. 11 is a control block diagram of a conventional guidance device.

[Explanation of symbols]

1: Radome or light dome, 2: Optical lens, 3: 2
Dimension detector, 4 Dewar, 5 Shell, 6 Inertial sensor, 7 A / D converter, 8 Image processor, 9 Target extraction processing circuit, 10 Target tracking processing circuit, 11 Gain adjuster , 12 ... Phase adjuster, 13 ... Derivative calculator, 14 ... Adder, 15 ... Delay time control circuit, 16 ... Delay circuit, 17 ...
Gain: 18: distortion correction memory, 19: temperature correction memory, 20: optical lens temperature monitor, 21: tracking point angle signal, 22: tracking point angle differential signal, 23: attitude angular velocity signal, 24: guidance signal, 25: flying Spherical body, 26: field of view of two-dimensional detector, 27: inertial reference coordinate axis, 28: center of the field (machine axis), 29: target, 30: attitude angle, 31: tracking point angle, 32: visual line angle, 33 ... Integration, 34: induction signal filter, 35: charge storage time of each horizontal line of the two-dimensional detector, 36: charge transfer time of each horizontal line of the two-dimensional detector, 37: focal length f of optical lens, 38
... Target incident angle θ in the case of focal length f, 39... Image height y on the two-dimensional detector in the case of focal length f, 40. Graph of the optical lens position in the case, 42... The target incident angle θ ′ in the case of the focal length f ′, 43... The image height y ′ on the two-dimensional detector in the case of the focal length f ′, 44. , 45 ... y =
Graph of fSin θ, 46: Image height y of optical system and incident angle θ
Y ′ = f ′ fluctuated by temperature change
Sin θ ′ graph, 48: gimbal mechanism, 49: space stabilization processing circuit, 50: attitude angle signal, 51: gimbal swing angle command, 52: gimbal center, 53: gimbal angle, 54: tracking error angle, 55 ... Gimbal angle with respect to the inertia reference coordinate axis, 56 ... Homing head gain.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI G06T 1/00 H04N 7/18 G H04N 7/18 G06F 15/62 380 (58) Investigated fields (Int. Cl. ⁶ , DB Name) F42B 15/01 B64C 13/18 F41G 7/22 G01S 3/782 G05D 1/12

Claims (5)

(57) [Claims] 1. An image-guided flying object guidance device
An optical lens fixed to the body to collect incident light in a predetermined direction, a two-dimensional detector capable of forming an image condensed by the optical lens, and an output image signal of the detector. An image processor that extracts and tracks a target and detects the angle of the target from the center of the field of view as a tracking point angle, and a differential calculator that differentiates a tracking point angle signal of the target detected by the image processor, an inertia sensor for detecting a posture angular velocity of the flying object, situated in front of the differential arithmetic unit, add the target
The tail point angle signal is multiplied by a gain, and the
Flying point detected by the tail point angle differential signal and the above inertial sensor
Gain adjuster to adjust the amplitude difference of body posture angular velocity signal
And the attitude angular velocity signal output by the inertial sensor
Adjust the time delay of the attitude angular velocity signal with respect to the tracking point angle signal.
A phase adjuster to be adjusted, and a tracking point output from the differential calculator
The time delay is adjusted via the angle differential signal and the phase adjuster.
And an adder for adding the attitude angular velocity signal of the flying vehicle. 2. A phase adjuster having a delay circuit for giving a delay time to an output signal, the charge accumulating time of a two-dimensional detector, and after a charge accumulation, a tracking point angle signal output by an image processor is differentiated by a differential calculator. 2. The attitude angular velocity signal is provided with a delay corresponding to a time obtained by subtracting a processing time of the inertial sensor from a time until the output of the tracking point differential signal is differentiated.
Flying object guidance device as described. 3. A phase adjuster having a circuit for controlling a delay time of a delay circuit for each frame of an image signal detected by a two-dimensional detector, wherein a phase is adjusted according to an angle from a visual field center to a target tracking point. The flying object guidance device according to claim 2, wherein the delay time is controlled. 4. A gain adjuster in which distortion data of an optical lens is stored in advance as a correction value, and performs gain correction on a tracking point angle signal according to an angle from the center of the visual field to a target tracking point. The flying object guidance device according to claim 1. 5. An optical lens temperature monitoring device for measuring the temperature of an optical lens, wherein a gain adjuster performs gain correction for a variation in an equivalent focal length of the optical lens due to a temperature change. The flying object guidance device according to claim 1 or 4.