JP2644121B2 - Radar equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device, and more particularly to an improvement in a target detecting means of the radar device.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram of a conventional radar device, which is similar to a diagram of a radar technology issued by, for example, the Institute of Electronics and Communication Engineers. In the figure, reference numeral 1 denotes an A / D conversion circuit for performing A / D conversion of an input signal.
Input video signal. Reference numeral 2 denotes a range gate circuit that performs sampling at a certain distance, and receives a signal from the A / D conversion circuit 1 as an input. Reference numeral 3 denotes a Doppler filter circuit for detecting a target speed, which receives a signal from the range gate circuit 2 as an input. Reference numeral 4 denotes a detection circuit for detecting intensity, and receives a signal from the Doppler filter circuit 3 as an input.

FIG. 4 is a diagram showing a relationship between a target detection range gate and a base unit altitude. In the figure, 9 is an aircraft on which a radar device is mounted, and 10 is a target.

Next, the operation will be described. The A / D conversion circuit 1 converts the input I and Q video signals into digital signals and outputs the digital signals to the range gate circuit 2. The range gate circuit 2 samples only a video signal corresponding to a predetermined range (distance) and outputs it to the Doppler filter circuit 3. The Doppler filter circuit 3 has a plurality of filters, and divides an input signal into speeds. That is, the speed can be obtained from the Doppler frequency of the input signal by the following equation. can do.

V = λf _d / 2 v: speed λ: wavelength f _d : Doppler frequency

[0006] A signal is output from the Doppler filter circuit 3 to the detection circuit 4, and when the intensity of the speed is equal to or more than a predetermined value, it is determined that the target exists. When that is the example above signal had an amplitude of the voltage value, for example, 10V, when the reference value 8V, determines that the target to which the reference value e Yue, exceeds the reference value when the reference value was set to 15V Because there is no target, it is not determined as a target.

[0007] As shown in FIG.
Consider a radar device that detects an approaching target 10 at a certain distance. The hatched portion shown in FIG. 4 is a predetermined range (distance) _RT and the base unit altitude is _RH . When the target 10 passes _RT , the range gate circuit 2 at that time
Is input to the Doppler filter circuit 3 and detected by the detection circuit 4 as a target.

FIG. 5 is a block diagram of a monopulse radar device which is another example of a conventional radar device, in which the azimuth is determined from the amplitude ratio of Σ (sum channel) and Δ (difference channel). In the figure, reference numeral 5 denotes A to which the ΣI video signal, ΣQ video signal, ΔI video signal, and ΔQ video signal are input.
/ D conversion circuit, 6 is a range gate circuit that receives a signal from the A / D conversion circuit 5, 7 is a Doppler filter circuit that receives a signal from the range gate circuit 6, and 8 is a signal from a Doppler filter circuit 7. Is a detection circuit that receives as input.

The operation is the same as that of the radar apparatus shown in FIG. 3 except that video signals of .SIGMA.I, .DELTA.Q, .DELTA.I, and .DELTA.Q are used.

[0010]

[Problems that the Invention is to Solve] Since the conventional radar apparatus is constructed as described above, range gate circuits video signal corresponding to a distance defined Oh <br/> et beforehand only
Is sampled, for example, when the range (distance) of the range gate circuit matches the base unit altitude , that is , the position of the aircraft
If the location is a R _T = R _H as shown in FIG. 4, whether the target
Reflected wave al are input to the reflected wave (clutter) simultaneously Doppler filter circuit from the ground surface, phenomenon Ji raw of the target signal at the output of the de-plug filter circuit Ru buried in clutter, that the target detection difficult There was a problem.
In order to avoid that, each range (distance) is different.
Prepare the plurality of range gate circuit comprising: a mother ship advanced R _H
Range gate at any distance other than the matching distance _RT
If the target is detected by the circuit , the target signal
Can be prevented from being buried in the filter , but with such a configuration, the number of Doppler filter circuits and even later
The number of detectors in the stage also increases according to the number of range gate circuits.
However, there is a problem that the scale of the apparatus is significantly increased.

The present invention has been made to solve the above problems, and can prevent a phenomenon that a target cannot be detected due to a reflected wave from the ground surface without increasing the size of the apparatus. An object is to obtain a radar device.

[0012]

A radar apparatus according to the present invention comprises a plurality of range gate circuits, a range gate control circuit for switching a range gate circuit for sampling among the plurality of range gate circuits based on altitude information, and And a range gate switching circuit.

[0013]

In the present invention, a plurality of range gate circuits are provided so that the range (distance) does not match the altitude of the base unit.
Since the range gate circuit is switched based on the altitude information to change the sampling range, it is possible to prevent a phenomenon that a target cannot be detected due to a reflected wave from the ground surface.

[0014]

FIG. 1 is a block diagram of a radar apparatus according to an embodiment of the present invention. 3, the same reference numerals as those in FIG. 3 denote the same or corresponding parts, 11 denotes a range gate bank circuit in which N number of range gate circuits 14 are collected, and 13 denotes a range gate circuit 14 employed in the range gate bank circuit 11.
Is a range gate switching circuit for controlling the range gate switching circuit 13 based on the base unit altitude information.

Next, the operation will be described. The range gate bank circuit 11 includes N range gate circuits 14, each corresponding to a different range (distance). The range gate control circuit 12 outputs a control signal for switching the range gate to the range gate switching circuit 13 based on the input base unit altitude information so as not to employ a range gate at a distance corresponding to the base unit altitude. The range gate switching circuit 13 switches to a range gate circuit 14 employed in the range gate bank circuit 11 according to a control signal from the range gate control circuit 12. In the same manner as in the prior art, of the digital signals converted by the A / D conversion circuit of the I and Q video signals, a video signal corresponding to a range determined by the range gate circuit 14 employed is sampled, and a Doppler filter is provided. Output to the circuit 3 and output to the detection circuit 4 for determination.

In this embodiment, N range gate circuits 14 are provided and the range gate circuits 14 are switched based on the base unit altitude information so that the base unit altitude does not match the range gate. A signal of a reflected wave from the ground is no longer output to the Doppler filter circuit 3, and a radar device which does not target the reflected wave from the ground and is not easily affected by clutter can be obtained without increasing the scale of the device. be able to.

FIG. 2 is a block diagram of a monopulse radar device according to another embodiment of the present invention. In the drawings, the same reference numerals as those in FIGS. 1 and 5 denote the same or corresponding parts. Reference numeral 15 denotes a range gate bank circuit in which N range gate circuits 16 are collected. This is a range gate switching circuit that switches the gate circuit 16.

As shown in the embodiment of FIG. 2, even when applied to two channels of Σ and Δ, the same effect as in the above-described embodiment can be obtained.

[0019]

As described above, according to the radar apparatus of the present invention, a plurality of range gate circuits and a range gate control for switching a range gate circuit to be used among the plurality of range gate circuits based on altitude information. Since the circuit and the range gate switching circuit are provided, the range gate can be switched when the range gate is in a range (distance) corresponding to the altitude of the base unit. There is an effect that it is possible to obtain a radar device which does not cause a phenomenon that it cannot be detected by being buried in the radar.

[Brief description of the drawings]

FIG. 1 is a block diagram of a radar device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a monopulse radar device according to another embodiment of the present invention.

FIG. 3 is a block diagram of a conventional radar device.

FIG. 4 is a diagram showing a relationship between a target detection range kate and a base unit altitude.

FIG. 5 is a block diagram of a conventional monopulse radar device.

[Explanation of symbols]

 1,5 A / D conversion circuit 3,7 Doppler filter circuit 4,8 detection circuit 11,15 range gate bank circuit 12 range gate control circuit 13,17 range gate switching circuit 14,16 range gate circuit

Claims (1)

(57) [Claims] 1. A radar apparatus for detecting a target, comprising: a plurality of range gate circuits; a range gate switch circuit for switching a range gate circuit to be used among the plurality of range gate circuits; And a range gate control circuit for performing control based on the radar.