JPS61180173A - Airframe guidiance equipment - Google Patents

Abstract

PURPOSE:To obtain a high-precision, high-stability guiding device by providing a synthetic aperture radar, a synthetic aperture radar image processing circuit, a reference image data storage circuit, an image data comparing circuit, and a signal processing circuit. CONSTITUTION:The synthetic aperture radar image processing circuit 2 processes observation data, obtained by the synthetic aperture radar 1, on real- time basis to select and extract image data on the periphery of a target within a preset range and output image data one after another while updating them according to the flight of an airframe. The image data comparing circuit 4 compares reference image data read out of a memory 32 with image data outputted from the processing circuit 2 to output a two-dimensional difference signal, which is supplied to the signal processing circuit 5. The circuit 5 calculates the relative speed vector based upon the target on the basis of the difference signal and supplies it to a guidance controller 100 which utilizes INS (inertial navigation system). The controller 100 controls the guidance of the airframe through the INS while utilizing the signal so that the target is displayed in the center of the image at any time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flying object guidance device, and more particularly to a flying object guidance device that uses a spotlight mode synthetic aperture radar as a sensor to guide a flying object in homing to a target.

[Conventional technology]

2. Description of the Related Art Homing guidance devices are well known in which a flying object is equipped with various guidance devices that utilize radio waves, infrared rays, etc. and used to guide homing toward a predetermined target. These conventional homing guidance devices use the relative velocity vector with respect to the target obtained by active or passive methods.
S (Inertial Navigation S
The flying object is guided to the target via a flying object guidance and control device that utilizes an inertial navigation system (Inertial Navigation System).

[Problem that the invention seeks to solve]

However, this type of conventional homing guidance device has the following technical drawbacks.

In other words, in the conventional homing guidance device described above, as the guided flying object approaches the target, it becomes relatively larger within the detection range of the sensor, and when it approaches the target, such as immediately before collision, it expands to the full detection range, making it difficult to guide the flying object toward the target. Therefore, the relative velocity vector obtained from the Senna system contains a large error and becomes meaningless, making the guidance control system unstable and making accurate guidance impossible! There is a drawback of 5.

Also, VOR (VHF 0nni Range) TA
CAN (TACtical Air Navigator)
tion), NDB (Non Directional
rodio Beacon)/ADF(Auto
matic Direction Finder)
The so-called blind cone (bl
Therefore, when radio waves emitted by these radio navigation devices are used to perform homing guidance, the disadvantage is that the operation is greatly disturbed on the ground, directly above the beacon station. be.

Furthermore, the method of using synthetic aperture radar as an inductive sensor, which is considered as a means to avoid the above-mentioned drawbacks, does not have a compact real-time image processing device, so it is almost impossible to implement it for relatively small normal flying objects. There is a drawback.

OBJECTS OF THE INVENTION N. High precision which eliminates the above-mentioned drawbacks.

An object of the present invention is to provide a highly stable synthetic mass radar flying object guidance device.

[Means for solving problems]

Equipment #L of the present invention is a flying object guidance device that guides flying objects, including aircraft, toward a target. A synthetic aperture radar image processing circuit that processes data in real time, selectively extracts image data in the vicinity of the target over a preset range, and outputs the image data while updating it one after another according to the flight of the projectile, and image data in the vicinity of the target. a reference image data storage circuit that stores the reference image data as reference image data; an image data comparison circuit that compares the reference image data with the image data that is successively updated in flight and obtains a difference signal between the two; A relative velocity vector with respect to the target is calculated based on the difference signal, a guidance signal L to the flying object guidance control device, an antenna pointing control signal of the synthetic aperture radar, and an image processing range of the synthetic aperture radar image processing circuit. and a signal processing circuit that outputs an image processing range control signal that controls the image processing range in accordance with the distance to the target.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the flying object guiding device of the present invention.

The configuration of the embodiment shown in FIG. 81!1 is as follows: synthetic aperture radar 1° synthetic amount radar image processing circuit 2. Reference image data storage circuit 39 Image data comparison circuit 4. It is configured with a signal processing circuit 5, etc., and '! Figure 1 shows a flying object guidance control device 100.
t- is also shown.

The synthetic aperture radar 1 has an antenna 11. Coherent radar transceiver 12. A spotlight mode synthetic aperture radar equipped with a radar old code processor 13, an antenna servo system 14, etc.
ar, hereinafter abbreviated as SAR.

The normal 8AR scans the ground at a constant distance to the side in the direction of movement of the projectile with a constant scanning width and is expanded in the distance and azimuth directions to obtain two-dimensional observation data. The observation data is later compressed in the distance and azimuth directions and reproduced as an image.

On the other hand, SAR operated with a spotlight shade does not irradiate the transmitting beam continuously over the entire Meijo area, but instead uses an operational mode called 1j, 5 quint (blind glare) mode to aim at the target ahead in the direction of a preset bush glare angle. guides the mounted flying object to capture and track a small area containing the area.

Figure 2 Guidance of flying object by Hayabusa glare mode t-:a
E! A. It is an explanatory diagram for guiding people to stare at the bushes.

If the target is captured in the direction of the homing start position P and the look angle θ is set, and the target is fully tracked with the velocity vector V, and the target is collided with the target future position itQ, the trajectory of the projectile will be the same as the flight track hole. Draw an arc.

The glare angle θ shown in FIG. 2 is set to an optimal value in consideration of the number of spotlights to be formed and other operating conditions. The basics of guidance using Spotlight Mode 5ARvc is to approach a spot in a small area while obtaining the relative velocity vector with the target by using this glaring guidance, and the spot range is usually a few hundred meters square at most. Since signal processing targets reflected waves from sex(
It has various features such as reduced antenna size (ambiguity) and miniaturization of the antenna.

Now, the synthetic aperture radar 1 receives an antenna directional control signal from a signal processing device 5, which will be described later, and uses an antenna servo system 1.
A radar signal processor receives a 1g signal received from the spot range at a preset data rate while capturing the spot range including the target in the direction of the blind look angle. 13. Transmission and reception to and from the spot range are carried out by a coherent transceiver while maintaining the coherency of transmission and reception, and the transmission signal is L F M (Linea
rFM) pulses at a predetermined repetition rate, and the received signal supplied to the radar signal processing a13//C is digitalized by an A/D converter over a processing range controlled by an image processing range control signal, which will be described later. After the data is converted into data, it is supplied to the synthetic aperture radar image processing circuit 2 as observation data via an interface circuit or the like.

Figure 3 is a characteristic diagram of the spot mode SAR irradiation field showing the characteristics of the irradiation field by spotlight mode SAR, and Figure 4 shows the Doppler frequency characteristics of the received signal from the equinormal distance of the spot tweet mode SAR irradiation field in Figure 3. It is a Doppler frequency characteristic diagram for explanation.

The embodiment of FIG. 1 will be explained below with reference to Nos. 3 and 41 'f: f5i! Let's go.

The synthetic aperture radar 1, which operates as a SAR in spotlight mode, emits a single beam B''fr of a nine-narrow beam with a viewing angle shown in FIG. s6 irradiate. When using S ARt in spotlight mode, all points within this spot irradiation field S are irradiated simultaneously. Xl, X,
...Equidirect distance R8 from the flying object to each point indicated by Xn
The relative orientation between each reflection point and the flying object changes over time, and the spot irradiation field S receives a predetermined number of repetitions of the transmitted beam while the reflected wave returns at a predetermined data rate. The range and azimuth compression results are reproduced as image data.

The synthetic aperture radar image processing circuit 2 is a part that receives the output of the synthetic aperture radar 1, that is, the two-dimensional received signal from the spot irradiation field S shown in FIG. 3, and performs range compression and azimuth compression of the signal. It is equipped with a built-in range compression circuit, corner turning circuit, azimuth compression circuit, etc. to perform compression in the range and azimuth directions.

The transmission pulse of the time-domain signal iLFM output from the radar signal processor 13 is subjected to known compression processing such as passing through a dispersion delay line whose time delay characteristic is opposite to that of the transmission pulse of the time-domain signal iLFM outputted by the radar signal processor 13 in the range compression circuit to perform range compression. The turning circuit is modified to rearrange the data arranged in the range direction in the azimuth direction, and then azimuth compression is performed.

When the azimuth compression circuit receives the output of the corner turning circuit, it converts it into a frequency domain signal and performs azimuth compression as described below.

@Equi-orthogonal reflection point of spot irradiation field S in Figure 3.

For example, X, , X, . . .

The reflected signals from these equidistant reflection points have their spreads in the range direction compressed through range compression, and then are each subjected to azimuth compression processing through the Doppler frequency.

As shown in Figure 8g4, the equi-orthogonal reflection point Xl has a positive Doppler frequency fzk at the compression processing start time t=Q, and as the azimuth angle θ between the flying object and Xl increases with time, the Doppler frequency with respect to Xl decreases. , this rate of decrease is almost linear over a short period of time. Regarding the equi-orthogonal reflection point X2, its data is acquired at a slightly larger relative azimuth than for Xl, so that
In the case of l, Eri also has a lower Doppler frequency f8 to Xl
The known azimuth compression process also shows a Doppler frequency that decreases at the same rate of gradient decrease as The time rate of change of this Doppler frequency, which is also the frequency bandwidth of the received signal from the reflection point, is determined over the total processing time T, and its conjugate function is used as the azimuth reference function, and this is multiplied by the signal after range compression. The azimuth compression is performed using the same method, but in this embodiment, the azimuth compression is basically performed using almost the same method. However, the normal 8. It is impossible to generate zero Doppler when the irradiation field is viewed at the lower part of the right angle side as in AP-, and therefore, Doppler frequency shift processing, etc. due to this is naturally unnecessary.

Now, equi-perpendicular points Xl, X, as shown in FIG.

The time domain data obtained from Xn, etc. after range compression and including the Doppler frequency described above is converted to frequency domain data again and then supplied to the azimuth compression circuit, resulting in the Doppler frequency change shown in Figure 4. multiplied by the built-in local oscillator frequency and the mixer with one frequency change y4 equal to the rate, n respective constant frequency Doppler frequencies are obtained. These n Doppler frequencies each have a constant frequency, but the frequency difference between them maintains the frequency difference shown in FIG. 4.

Next, these n Doppler frequencies are processed by digital FFT (F
(ast Fourier Transform) circuit. In this way, the received signals from the equi-orthogonal reflection points X, , X, . . . Output.

Reflection points Xl, X,...
・Although the range and azimuth compression for Most of the arithmetic processing and processing control is performed using a non-Neumann image pipeline processor, making almost real-time processing possible in practice.

A non-Neumann image pipeline processor is a 7=5 LSI recently developed for the field of image processing, and it adopts a data flow one-way and variable pipeline groove bottom architecture, and is capable of high-speed processing, compared to the conventional one of this type. It is significantly smaller and lighter than an image processor, and by combining this with the spotlight mode SAR, the entire system can be mounted on a small flying object.

The reduction in processing time and reduction in size and weight achieved by this non-Neumann image pipeline processor will be described in more detail as follows.

The numerical calculation processing time by FFT in azimuth or range compression, which requires the most processing time in the process of reproducing an image from data obtained by applying SAR, is 1 on average for normal SAR using 1024-point FFT.
Let's consider the numerical calculation processing time in image processing.

A typical example of the highest speed processing using conventional methods uses a high-precision minicomputer-level combination machine and an array processor, such as FloatingPoint's AP-9, to process the data from this erratic 1024-point FFT. 1
Approximately 300m5 when used in combination with 20Bt- for high-speed processing
It is processed by EC.

On the other hand, in this embodiment, the non-Neumann image pipeline processor, which is the uLsI microprocessor, is basically a 5MIPS (MegaInstrument)
ion per 5 seconds), and it takes about 60m5EC to execute all the same processing contents.This significant reduction in processing time makes it possible to process real-time images of images in real time, and it also requires physical processing. The significant reduction in size and volume makes it possible to mount and equip practically all flying vehicles.

The image data outputted from the same spot in this way is constantly updated as the flying object flies and is supplied to the output image data comparison circuit 4. As the processing range,
This target is selected as the one that is on the image at the beginning of the flight and is the target of the guided approach. Spotlight mode SAR,
As is commonly known, various functions such as the ability to search for and track targets in the air, the ability to maintain correct navigation while spot-irradiating a specific target on the ground, or the optimal guidance of missiles, etc. However, when using any of these functions, a desired target is first set in the initial stage of operation, and data from a range of several hundred meters around this target is converted into a synthetic aperture radar image as near-target image data. From the processing circuit 2 to the reference image data storage circuit 3
L5 is manually controlled.

A target setting memory selector 3 is provided in the reference image data storage circuit 3.
1 and notes! The target setting memory selector 31 operates at the same time as supplying image data near the target by manual control as described above, outputs a command regarding the address and memory size of the memory 32 in which this data is to be stored, and sets the target in the memory 32. In this embodiment, image data near the target is supplied to the memory 32 using manual control at the beginning of operation, but depending on the purpose of operation, the target may be known. In this case, there is no problem even if the image data including the target is stored in the memory 32 in advance.

Now, the image data comparison circuit 4 compares the reference image data read from the memory 31 and the image data successively updated and output from the synthetic aperture radar image processing circuit 2 according to the flight of the flying object using a known map matching method. It outputs a two-dimensional difference signal and supplies it to the t-signal processing circuit 5.

The signal processing circuit 5 calculates a relative velocity vector with respect to the target based on this difference signal, and supplies it as a guidance signal to the flying object guidance control device 100 that utilizes IN8t. The flying object guidance control device 100U uses the guidance signals thus supplied to guide and control the flying object via the INS' so that the target is always displayed at the center of the image. In this case, the signal processing circuit 5μ
An antenna directional control signal is generated to control the directional direction of the antenna 11 of the composite amount Loredae in the direction that makes the difference signal zero, and this signal is supplied to the antenna servo system 14 to control the antenna 11.
Performs zero pointing control. The signal processing circuit 5 further includes:
The distance component to the target is extracted from the input difference signal, and based on the distance component data of Kurie, an image processing range control signal is generated, and this signal is sent to the radar signal processor 13 of the synthetic aperture radar l.
supply to.

The friend image processing range control signal mentioned above is a range gate signal that always sets the distance range in the image display to a constant state as the flying object approaches the target, and the radar signal processor 13 receives this signal and The processing range of received data input via the coherent radar transceiver 12 is controlled to maintain a constant distance range of the displayed image.

As described above, by using the synthetic aperture radar using the spotlight mode t-, stable and accurate guidance of a flying object based on glare guidance control can be carried out practically in real time.

The present invention utilizes a synthetic aperture radar in spotlight mode as a sensor, is significantly smaller and lighter, and performs image processing in practically real time using a high-speed ft processor. The basic feature is that the flying object is guided while comparing the image data updated according to the
Various modifications of the embodiment shown in FIG. 1 are possible.

For example, in this embodiment, a non-Neumann image pipeline processor with an L8I configuration is used as a high-speed processor that is significantly smaller and lighter.
It is clear that this can be implemented in the same way even if the processor is replaced with another processor having substantially the same shape and volume and having substantially the same functions.

In the synthetic aperture radar image processing circuit 2, Doppler frequency extraction of the received signal from each reflection point of the spot is performed by mixing the received signal with a local oscillation frequency having the same Doppler frequency slope as the received signal, and then performing digital FFT'.
Although the method of selective extraction via the filter bank used is expensive, it may be replaced with other Doppler frequency extraction means having an equivalent function.

Furthermore, the induction signal output from the signal processing circuit 5 is INS
However, it is clear that this flying object guidance device 100 can be implemented in the same manner even if the flying object guidance device 100 uses guidance devices other than INS. All of these can be easily implemented without departing from the spirit of the invention.

〔Effect of the invention〕

As explained above, if the present invention is implemented, a flying object guiding device for guiding a flying object such as an aircraft to a target,
A synthetic aperture radar operated in spotlight mode is used as a sensor to create a non-Neumann image pipeline.
In practical terms, the processor is used to perform image processing in real time, and as a premise of the 4T, the onboard flying object is compared with preset reference image data near the target and image data that is updated as it flies. It is possible to fundamentally eliminate the unavoidable large error noise received by conventional homing guidance devices when they are very close to each other, such as immediately before a collision, or when they are close to each navigation device, resulting in stability and accuracy. This has the effect of realizing a small and lightweight flying object guidance device that can significantly improve performance.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of an embodiment of the flying object guidance device of the present invention, ftJ2 is a blind glare guidance explanatory diagram for explaining the guidance of a flying object in the blind glare mode, and Figure 3 is a spotlight Mode 5AR (synthetic aperture radar)
Spotlight mode SAR showing the characteristics of the irradiation field by
Irradiation field characteristic diagram, FIG. 4 is a detailed Doppler frequency characteristic diagram illustrating the Doppler frequency characteristic of the received signal from the equi-orthogonal distance point of the spotlight mode 8ARR radiation 1F of FIG. 3. 1... Synthetic aperture radar, 2... Synthetic aperture radar image processing circuit, 3... Reference image data storage circuit, 4... Image data comparison circuit, 5...
...Signal processing circuit, 11...Antenna, 1
2... Coherent radar transceiver, 13...
... Radar signal processor, 14 ... Antenna servo system, 31 ... Target setting memory selector,
32...Memo! J, 100... Flying object guidance control device. $2 Figure 83 Ward 84 Figure

Claims (1)

[Claims] In a flying object guidance device that guides flying objects including aircraft toward a target, a spotlight mode (spotlig
Synthetic aperture radar operated in ht mode) and the observation data acquired by this synthetic aperture radar are processed in real time to selectively extract image data near the target over a preset range, and to sequentially extract image data according to the flight of the projectile. a synthetic aperture radar image processing circuit that updates and outputs the output; a reference image data storage circuit that stores image data near the target as reference image data; and the image data that is successively updated in accordance with the reference image data and flight. an image data comparison circuit that obtains a difference signal between the two while comparing the difference signals; and an image data comparison circuit that calculates a relative velocity vector with respect to the target based on the difference signal, and also provides a guidance signal to the flying object guidance control device and an antenna of the synthetic aperture radar. A flying object characterized by comprising a signal processing circuit that outputs an image processing range control signal that controls the image processing range of the synthetic aperture radar image processing circuit in accordance with the distance to the target in addition to the directional control signal. Guidance control device.