JPH10232277A - Radar equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain radar equipment for canceling a phase change due to interference of an antenna pattern and a body bottom and influence of a radome. SOLUTION: In the radar equipment comprising an antenna 3 for receiving a reflected wave of a transmitted wave, a receiver 5 for amplifying and detecting a radar received wave received by the antenna, and a signal processor 6 for extracting a target signal from the received detected signal received by the receiver, the radar further comprises a phase compensating means for correcting a phase of the received signal before or in a step of processing the signal by the processor 6. And it further alters a thickness of a radome 4 for containing the antenna 8 therein in a radiating direction corresponding to the radiating direction of a radar transmitted wave as the compensating means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse Doppler radar for detecting, detecting, and tracking a target, generally referred to as a Doppler radar, a synthetic aperture radar for imaging and recognizing a target, and a signal processing apparatus for an inverse synthetic aperture radar. It is about.

[0002]

2. Description of the Related Art FIG. 14 is a block diagram showing the configuration of a conventional airborne radar apparatus. In the figure, 1 is a transmitter that generates and amplifies a radar transmission signal, 2 is a transmission / reception switch that transmits a radar transmission signal from the transmitter to the antenna 3, and transmits a reception signal from the antenna 3 to the receiver. An antenna that radiates radar radio waves into space and receives reflected waves from targets,
40 is a radome for protecting the antenna, 5 is a receiver for amplifying and detecting a signal received from the transmission / reception switch, and 6 is a signal processor for extracting a target by Doppler processing the detected signal. FIG. 15A is a conceptual diagram of a system in an airborne state, FIG. 15B is an antenna pattern diagram of the antenna 3 in an airborne state, FIG. 16A is an external view of a radome, and FIG. FIG. 4B is a diagram illustrating a phase delay of a signal when transmitted through a radome.

[0003] The operation of the conventional radar apparatus having the above-described configuration will be described. First, a transmitter 1 generates a transmission seed signal and amplifies the signal to a required power level. The amplified transmission seed signal passes through the transmission / reception switch 2 and the antenna 3 and the radome 4, and is emitted to the space as a radar transmission wave.
The radiated radar transmission wave propagates in space and irradiates a target, a part of the power is reflected and becomes a reflected wave, propagates in space and transmits through the radome 40, and again the antenna 3 and the duplexer 2
The signal is amplified and detected by the receiver 5 and output to the signal processor 6. The signal processor 6 analyzes the frequency of the detected signal for each distance gate, and performs pulse Doppler processing for extracting a target Doppler component, or a synthetic aperture radar (SA).
R) processing, inverse synthetic aperture radar (ISAR) processing,
Detect targets and generate images. Here, as shown in FIG. 15A, the antenna 3 is mounted on the bottom of the aircraft, and the depression angle is 0 °.
When an antenna pattern is to be formed in the direction, the antenna pattern cannot be formed in the desired 0 ° direction due to interference between the antenna pattern and the bottom of the machine, and the pattern is formed at a depression angle θ (below 0 °). In addition, the interference between the antenna pattern and the bottom of the
In the vicinity, due to the transmission phase delay of FIG. 16 (b) due to the constant thickness radome shown in FIG. 16 (a), the phase pattern changes according to the radiation angle, and has a slope as shown in FIG. 15 (b). Characteristics.

[0004]

A conventional radar device is:
With the above configuration, the depression angle changes according to the angle of the received wave in accordance with the radiation direction of the transmitted wave, and changes in the attitude angle of the aircraft due to the fluctuation of the aircraft, and the phase pattern also changes. That is, there is a problem that phase modulation occurs in the received signal with a change in the phase pattern, and an error occurs in the result of the signal processing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a radar apparatus in which the influence of the antenna pattern and the thickness of the interference radome on the bottom of the fuselage and other phase changes due to the fluctuation of the fuselage are corrected. Aim.

[0006]

SUMMARY OF THE INVENTION A radar apparatus according to the present invention comprises an antenna for receiving a reflected wave with respect to a transmission wave, a receiver for amplifying and detecting a radar reception wave received by the antenna, and a reception apparatus for receiving the reception wave. In a configuration comprising a signal processor for extracting a target signal from a detection signal, a phase compensating means for correcting a phase of a received signal before the signal processor or in a process of signal processing is provided.

Further, as a phase compensating means, the radial thickness of the radome accommodating the antenna therein is changed in accordance with the radiation direction of the radar transmission wave.

Further, a phase compensation table is provided as phase compensation means, and the received signal is corrected by referring to the phase compensation table in the process of signal processing in accordance with the radiation direction of the radar transmission wave.

Furthermore, an inertial sensor is provided as a phase compensating means, and the received signal is corrected by the detected acceleration in the process of signal processing.

Still further, the inertial sensor has an azimuth (A
Z), elevation (EL) or AZ / EL combined inertial sensor.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. A radar apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a radar device according to the present embodiment, and a diagram illustrating a structure of a radome. FIG. 2 is a system conceptual diagram for explaining the operation of the apparatus according to the present embodiment.
(B) is an aerial pattern diagram of an aircraft mounted state without a radome. FIG. 3 is a diagram showing the transmission phase delay of the radome in FIG. 1, and FIG.
It is a figure explaining generation of the phase pattern of the received signal which combined the antenna of (b). In FIG. 1, reference numeral 4 denotes a radome whose thickness has been processed.

In the present embodiment, in the radar apparatus constructed as shown in the above-mentioned figure, the thickness of the radome 4 is changed with respect to the depression angle, and therefore, the phase delay of the received signal due to the radome transmission is consciously considered. It is changed with respect to the depression angle. By setting the phase characteristics shown in FIG.
Canceling the antenna phase pattern shown in (b),
As shown in FIG. 4C, the phase pattern of the received signal becomes constant. That is, even if the body on which the radar device is mounted changes its attitude angle and changes its depression angle, or a received signal corresponding to a radiation angle, a received signal has a constant phase pattern.

Embodiment 2 FIG. In the above embodiment, the thickness of the radome is changed in order to compensate the phase of the received signal. Here, a case where the signal processor corrects the phase in the process of extracting the target will be described. FIG. 5 is a block diagram showing a configuration of the radar apparatus according to the present embodiment, and FIG. 6 is a conceptual diagram of a system in an aircraft mounted state showing a target and a depression angle α. FIG. 7 is a diagram showing the relationship between the antenna phase pattern and the phase compensation pattern with respect to the depression angle according to the data table as the phase compensation means in the present embodiment. In FIG. 5, reference numeral 7 denotes a phase compensation data table having the characteristics shown in FIG.

In the present embodiment, the direction of the target position, that is, the amount of phase compensation for the target depression angle is stored as a phase compensation data table. This phase compensation data table 7 is stored in the signal processor 6, and as shown in FIG. 7, the phase compensation amount is referred to from the target detection information (azimuth and depression angle), and phase compensation is performed in the process of signal processing. .
Even in this case, as in the first embodiment, a constant phase pattern can be obtained with respect to the angle of the received signal even if there is a depression angle variation due to a change in the attitude of the body attitude.

Embodiment 3 In the above embodiment, the phase compensation data table is used to accompany the phase compensation of the received signal. However, here, a case where the inertia is detected using the inertia sensor and the phase correction amount is obtained from this value will be described. I do. FIG. 8 is a block diagram illustrating a configuration of a radar device according to the present embodiment, and FIG. 9 is a diagram illustrating a relationship between an aircraft on which the device is mounted and a target. As shown in FIG. 8, the apparatus according to the present embodiment has eight AZ inertial sensors that sense the movement of the antenna in the azimuth (AZ) plane. By integrating the acceleration signal output from the AZ inertial sensor, the amount of movement of the antenna between the pulses is calculated, and ΔR as the target distance difference between the pulses shown in FIG. 9 is calculated. This distance difference is converted into a phase amount θ (θ = 4πΔR / λ, λ: wavelength), and the received signal is phase-compensated. That is, by attaching the AZ inertial sensor instead of the thickness of the radome of the first embodiment,
For movement in the AZ plane such as depression angle fluctuation and body vibration,
A phase pattern in which the received signal is constant can be obtained.

The inertial sensor is not limited to the AZ inertial sensor alone. FIG. 10 is a block diagram showing a configuration of another radar device according to the present embodiment, and FIG. 11 is a conceptual diagram illustrating a state of an airframe in which the present device is mounted on an aircraft. As shown in FIG. 10, the apparatus of this embodiment is equipped with an EL inertial sensor indicated by 9 that senses the movement of the antenna in the elevation (EL) plane. By integrating the acceleration signal output from the EL inertial sensor, the amount of movement of the antenna between the pulses is calculated, and ΔR, which is the target distance difference between the pulses, is calculated. This distance difference is represented by the phase amount θ (θ = 4πΔR / λ,
λ: wavelength) and phase-compensates the received signal. That is,
Instead of the phase compensation data table of the second embodiment, EL
By attaching the inertial sensor, a phase pattern in which the received signal is constant can be obtained even with respect to movement in the EL plane such as depression angle fluctuation and body vibration.

The apparatuses according to the second and third embodiments may be combined. FIG. 12 is a block diagram showing a configuration of an apparatus based on this combination. In FIG. 12, an EL inertial sensor 9 is attached to the antenna 3 of the conventional system,
Further, a phase compensation data table 7 is stored in the signal processor 6. With this configuration, the phase compensation amount is referred from the target detection information (azimuth and depression angle), while the phase compensation amount of the body EL motion is calculated from the acceleration signal output from the EL inertial sensor, and the respective phase compensation amounts are used. Performs phase compensation of the received signal. That is, a phase pattern in which the received signal is constant with respect to the movement in the EL plane such as the depression angle fluctuation and the body vibration is obtained. Although not shown, a configuration using an AZ inertial sensor instead of the EL inertial sensor may be adopted.

Further, the AZ inertial sensor and the EL inertial sensor according to the third embodiment may be used together. That is, as shown in FIG. 13, ten AZ / EL inertial sensors that sense the movement of the antenna 3 in the AZ and EL planes are attached. In this way, the phase compensation amounts of the AZ and EL motions of the airframe are calculated from the acceleration signals output from the AZ / EL inertial sensor, and the received signals are phase-compensated. That is, a phase pattern in which the received signal is constant can be obtained even with respect to movement in the AZ and EL planes such as depression angle fluctuation and body vibration. Further, the AZ / EL inertial sensor 10 and the phase compensation data table 7 may be used in combination.

[0019]

As described above, according to the present invention, since the radome whose phase transmission characteristic changes with respect to the depression angle is used, the phase characteristic of the received signal becomes constant even when the depression angle of the radar radiation angle changes. Therefore, there is an effect that a correct signal for target detection can be obtained.

Further, since the phase compensation data table is provided for the depression angle, the phase characteristic of the received signal becomes constant even when the radar emission angle changes, so that a correct signal for target detection can be obtained. Has the effect.

Further, the inertial sensor is provided, so that the phase characteristic of the received signal becomes constant even when the depression angle changes in the corresponding plane of the aircraft, so that a correct signal for target detection can be obtained. There is.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a radar apparatus according to Embodiment 1 of the present invention and a diagram showing a structure of a radome.

FIG. 2 is a conceptual diagram of a system for explaining the operation of the device according to the first embodiment, and an antenna characteristic diagram corresponding to FIG. 2A without a radome for comparison.

FIG. 3 is a diagram showing a transmission phase delay of the radome of the first embodiment.

FIG. 4 is a diagram showing a phase pattern of a reception signal in the device of the first embodiment in which the radome of FIG. 1 and the antenna of FIG. 2B are combined.

FIG. 5 is a block diagram showing a configuration of a radar device according to Embodiment 2 of the present invention.

FIG. 6 is a conceptual diagram of a system for explaining a state in which an apparatus according to the second embodiment is mounted on an aircraft.

FIG. 7 is a diagram illustrating a relationship between an antenna phase pattern and a phase compensation pattern with respect to a depression angle according to the second embodiment.

FIG. 8 is a block diagram showing a configuration of a radar device according to Embodiment 3 of the present invention.

FIG. 9 is a diagram for explaining a relationship between an airframe equipped with the device according to the third embodiment and a target.

FIG. 10 is a block diagram showing a configuration of another radar device according to the third embodiment.

11 is a diagram for explaining a relationship between a body equipped with the apparatus of FIG. 10 and a target.

FIG. 12 is a block diagram showing a configuration of another radar device according to the third embodiment.

FIG. 13 is a block diagram showing a configuration of another radar device according to the third embodiment.

FIG. 14 is a block diagram illustrating a configuration of a conventional radar device.

FIG. 15 is a system conceptual diagram and an antenna characteristic diagram illustrating a conventional device mounted on an aircraft.

FIG. 16 is a diagram illustrating a structure of a radome and a transmission phase delay of the radome in a conventional radar device.

[Explanation of symbols]

Reference Signs List 1 transmitter, 2 transmission / reception switch, 3 antenna, 4 radome, 5 receiver, 6 signal processor, 7 phase compensation data table, 8 AZ inertial sensor, 9 EL inertial sensor, 1
0 AZ / EL inertial sensor.

Claims (5)

[Claims] 1. An antenna for receiving a reflected wave with respect to a transmission wave, a receiver for amplifying and detecting a radar reception wave received by the antenna, and a signal processor for extracting a target signal from a reception detection signal received by the receiver. And a phase compensator for correcting a phase of a received signal before the signal processor or in a process of signal processing. 2. The phase compensating means according to claim 1, wherein the thickness of the radome accommodating the aerial in the radial direction is changed in accordance with the radiation direction of the radar transmission wave. Radar equipment. 3. The phase compensating means is provided with a phase compensating table, and corrects a received signal with reference to the phase compensating table in a signal processing process in accordance with a radiation direction of a radar transmission wave. The radar device according to claim 1, wherein: 4. The phase compensating means includes an inertial sensor,
2. The radar device according to claim 1, wherein a received signal is corrected by the detected acceleration in a signal processing process. 5. The radar device according to claim 4, wherein the inertial sensor is an azimuth (AZ), elevation (EL), or AZ / EL combined inertial sensor.