JPH04290980A - Radar device - Google Patents

Abstract

PURPOSE:To prevent issue of erroneous alarm while the target detection probability is heightened irrespective of the angle of elevation of a radar beam. CONSTITUTION:To set the beam elevation angle of an aerial 3, a beam scan control circuit 4 is provided to give aerial the beam elevation angle information at the time of signal transmission and reception, and also is furnished with a video quantization circuit 7 which quantizes the radar video obtained through processing of a received signal from the aerial 3 at a certain slice level, and thereby senses if target exists. In a slice level setting circuit 6 the slice level is set in accordance with the beam elevation angle information.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar device that scans a radar beam in the elevation direction and automatically detects a target.

0002

2. Description of the Related Art FIG. 2 is a functional diagram showing a conventional radar device. In the figure, 1 is a transmitter that generates a transmission signal, 2 is a transmission/reception switch that switches between a transmission signal and a reception signal,
3 is an antenna that enables the beam to scan in the elevation direction; 4 is a beam scanning control circuit that outputs beam elevation angle information for scanning with respect to the antenna 3; 5 is a radar receiver that amplifies and detects the received signal and outputs radar video; A video quantization circuit 7 quantizes the input radar video according to the slice level set by the slice level setting circuit 6 to detect the presence or absence of a target.

Next, the operation will be explained. The transmission signal generated by the transmitter 1 passes through the transmission/reception switch 2,
Sent to antenna 3. The antenna 3 forms a beam in a designated elevation angle direction based on the beam elevation angle information from the beam scanning control circuit 4, and radiates a transmission signal into space.

On the other hand, radar radio waves as transmission signals radiated into space are scattered when they hit a target, and a part of them is received as reflected waves by the antenna 3 at the same beam elevation angle as the transmission. The signal received by the antenna 3 passes through the transmission/reception switch 2 again and is input to the radar receiver 5. The radar receiver 5 amplifies and detects the input received signal and outputs a radar video. The output radar video is compared in the video quantization circuit 7 with the slice level set in the slice level setting circuit 6, and the presence or absence of a target is determined according to the quantized data that is the comparison result.

By the way, the slice level for video quantization does not depend on the elevation angle of the radar beam;
In general, the state of radar echoes often differs depending on the elevation angle of the beam, so, for example, unnecessary clutter components from the ground etc. are more abundant in beams with lower elevation angles and decrease as the elevation angle becomes higher.

[0006]

[Problem to be Solved by the Invention] Since the conventional radar device is configured as described above, it is necessary to set the slice level for target detection to a low elevation angle beam with a lot of clutter, and to a high level to prevent false alarms. If the slice level is set to a low level to ensure the detection probability of a high-elevation beam, the detection probability for a high-elevation beam will deteriorate.On the other hand, if the slice level is set to a low level to ensure the detection probability of a high-elevation beam, false alarms due to clutter will occur for a low-elevation beam. There was an issue.

[0007] This invention was made to solve the above-mentioned problems, and regardless of the elevation angle of the radar beam,
The purpose is to obtain a radar device that can suppress false alarms without deteriorating detection probability.

[0008]

[Means for Solving the Problems] A radar device according to the present invention transmits, transmits, and sets the beam elevation angle of an antenna.
A beam scanning control circuit that outputs beam elevation angle information at the time of reception to the above-mentioned antenna, and a video quantizer that quantizes the radar video obtained by processing the received signal received by the above-mentioned antenna at a predetermined slice level to detect the presence or absence of a target. and a slice level setting circuit to set the slice level in accordance with the beam elevation angle information.

[0009]

[Operation] The video quantization circuit according to the present invention operates according to the slice level set corresponding to the beam elevation angle information.
The radar video is quantized, and according to the processing results, the detection probability is increased, the false alarm rate is reduced, and target detection can be realized with high sensitivity.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a transmitter, 2 is a transmission/reception switch, and 3
4 is an antenna, 4 is a beam scanning control circuit, 5 is a radar receiver, 6 is a slice level setting circuit, and 7 is a video quantization circuit, and their basic configurations are not significantly different from those of the prior art. Further, reference numeral 8 denotes a beam elevation angle information line for inputting beam elevation angle information from the beam scanning control circuit 4 to the slice level setting circuit 6.

Next, the operation will be explained. First, as in the case described in the prior art, a transmission signal generated by the transmitter 1 is sent to the antenna 3 via the transmission/reception switch 2. The antenna 3 forms a beam in a designated elevation angle direction based on the beam elevation angle information from the beam scanning control circuit 4, and radiates a transmission signal into space.

On the other hand, the radar radio wave as a transmission signal radiated into space is scattered when it hits a target, and a part of it is received as a reflected wave by the antenna 3 at the same beam elevation angle as that of the transmission. The signal received by the antenna 3 passes through the transmission/reception switch 2 again and is input to the radar receiver 5. The radar receiver 5 amplifies and detects the input received signal and outputs a radar video. The output radar video is compared in the video quantization circuit 7 with the slice level set in the slice level setting circuit 6, and the presence or absence of a target is determined according to the quantized data that is the comparison result.

Here, the slice level setting circuit 6 sets a slice level corresponding to the beam elevation angle information from the beam scanning control circuit 4, and outputs the set slice level to the video quantization circuit 7. For example, by setting the slice level to a high level at low elevation angles and a low level at high elevation angles according to the beam elevation angle information, it is possible to sufficiently increase the detection probability at high elevation angles while suppressing false alarms due to clutter at low elevation angles.

[0014]

As described above, according to the present invention, in order to set the beam elevation angle of the antenna, there is a beam scanning control circuit that outputs beam elevation angle information to the antenna during transmission and reception, and A video quantization circuit that quantizes the radar video obtained by processing the signal at a predetermined slice level to detect the presence or absence of a target, and the slice level setting circuit corresponds to the slice level with the beam elevation angle information. I configured it so that it is set by
The detection probability is not degraded even with a beam having a high elevation angle, and there is an effect that target detection can be realized with a low false alarm rate over a wide beam elevation angle range.

[Brief explanation of the drawing]

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

FIG. 2 is a functional diagram showing a conventional radar device.

[Explanation of symbols]

1 Transmitter 3 Aerial line 4 Beam scanning control circuit 6 Slice level setting circuit 7 Video quantization circuit

Claims (1)

[Claims] Claim 1: A transmitter that generates a transmission signal, an antenna that radiates the transmission signal from the transmitter into space and receives a reflected wave of the transmission signal from a target, and a beam elevation angle of the antenna is set. In order to do this, a beam scanning control circuit outputs beam elevation angle information during transmission and reception to the antenna, and a radar video obtained by processing the received signal received by the antenna is quantized at a predetermined slice level.
A radar device comprising: a video quantization circuit that detects the presence or absence of the target; and a slice level setting circuit that sets the slice level in accordance with the beam elevation angle information.