JPS6061669A - Radar equipment - Google Patents

Abstract

PURPOSE:To enable a highly accurate identification of a target with a small- scale equipment by using not only the radar sectional area of the target but also the absolute speed thereof as means for identifying the type of the target. CONSTITUTION:The relative speed from a Dppler filter 4 and the speed of own airplane obtained from other equipment through an interface circuit 10 are inputted into an absolute speed calculation circuit 9. The absolute speed calculated with the absolute speed calculation circuit 9, the radar sectional area calculated with a radar sectional area calculation circuit 5 and the altitude of the own airplane obtained from other equipment through the interface circuit 10 are inputted into a target identification circuit to identify the target.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to target type identification in a radar device.

A pulsed Doppler radar device is shown in FIG. In the figure,
(1) is the antenna, (2) is the receiver connected to (1), (3) is the range gate connected to (2), (4) is the Doppler filter connected to (3), (5 ) is a target identification circuit connected to (3) and (4). ' Among such pulsed Doppler radar devices, the one shown in FIG. 3 has conventionally been used in order to obtain high target identification accuracy even in non-scanning wide coverage radar devices.

In FIG. 3, (2) to (6) have the same functions as those in FIG. It's a sword, +21, (121,
(22H, (3Δ, fat, Qa+, (goods),
03), f41 * (14) + (24+), and Riyu are completely the same.

(11) and 1) are monopulse antennas having means for receiving sum and difference signals; (7) and 02
7) A direction detection circuit connected to LJ, (4) and 04] and @41, respectively, and (8) an antenna gain calculation circuit connected to (7) and 7).

Next, the operation will be explained. In the pulse Doppler radar device shown in FIG. 1, a signal received by the antenna il+ is amplified to a level equal to Hr by the receiver (2) and input to the range gate (3). The range gate (3) detects the distance R to the target and also detects the distance R to the target.
In 4), the relative velocity VR of the target and the received power Pr from the target are detected.

The received power P from the Doppler filter (4) and the distance R from the range gate (3) are determined by the radar cross section calculation circuit (6).
), and the target radar cross section σ is calculated according to the following equation.

σ = −P −Ril+ where: K: The radar cross section σ obtained by subtracting the constant is input to the target identification circuit (6), and the type of target is identified based on the magnitude of σ.

For example, when considering an aircraft-mounted radar device that detects a target approaching from behind as shown in FIG. 2, the target of the radar device may be a missile or an aircraft.

Typically, the radar cross section of an aircraft is about 100 times the radar cross section of a missile, so it is possible to identify a target based on the value of the radar cross section.

The above explanation is based on the assumption that the antenna gain does not differ depending on the target direction. In a radar device that scans the antenna beam, it can be assumed that the target is always captured at the maximum antenna gain, so the above assumption holds. Since the radar cross section differs greatly, the radar cross section cannot be calculated accurately unless the azimuth is detected.In other words, K in equation (1) is considered to be a function of the azimuth rather than a constant, and the fli equation is similar to the equation (2). can be changed.

Here, K': Constant θAZ 'Axis in the horizontal plane θBL' Azimuth in the vertical plane G(θ, 7.θIIL) 'θAZ, θ8. Therefore, in a non-scanning, wide-coverage radar system, if the radar cross section is calculated according to equation (1) with the configuration shown in Figure 1, the radar cross section σ will not be calculated correctly, and the target identification accuracy will be poor. Therefore, the direction of the target is detected and (21
It is necessary to calculate the radar cross section according to the formula and identify the target. As a device for this purpose, for example, a pulsed Doppler radar device shown in FIG. 3 can be considered.

The operations different from those in FIG. 1 will be explained.

The sum signal and difference signal received by the monopulse antenna (11) are input to each receiving system. Doppler filter (4
) and the difference d signal reception power from the Doppler filter (14) are input to the azimuth detection circuit (7), and by comparing the two, the azimuth UAZ in the horizontal plane is determined.
detected.

The orientation θ8L in the vertical plane is also detected in exactly the same way as the orientation θA2 in the horizontal plane.

Azimuth θ9 in the horizontal plane. and the orientation in the vertical plane θ8. ．． is input to the antenna gain calculation circuit (8), and the antenna gain G (θAZ, θ.L) in the target direction is output.

Radar cross section meter (5i has a range gate (
From 3), the distance R at target 1 is determined by the Doppler filter (4)
The received power Pr is calculated from the antenna gain calculation circuit (8).
Since the conventional non-scanning wide coverage radar device is configured as described above, in order to improve the target identification accuracy, the This method requires a separate receiving system, which has the disadvantage of increasing the size of the device.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by using not only the radar cross section of the target but also the absolute velocity of the target as a means of identifying the type of target, it is possible to An object of the present invention is to provide a pulsed Doppler radar device capable of highly accurate target identification with T5J capability without increasing the scale of the scanning wide coverage radar device.

An embodiment of the present invention will be described below with reference to the drawings. Fourth
In the figure, f1i to (6) are the same as or have the same function as a conventional pulsed Doppler radar device.

(10) is an interface circuit connected to other equipment (navigation equipment), and (9) is an absolute speed subtraction circuit connected to (4) and (1[1j).

In the invention shown in Fig. 4, is the operation different from that of the prior art? Tona
'f+ Talk b Fill f 7, - Doppler filter (
4), and the mother aircraft speed ■ψ obtained from another device (navigation equipment) through the interface circuit (101) are input to the absolute speed calculation circuit (9).

When considering an aircraft-mounted radar device that detects a target approaching from the rear as shown in FIG. 2, the absolute speed of the target approaching from the rear is given by the following equation.

ARA/. (3) In the absolute speed calculation circuit (9), the absolute speed Europe■ calculated by equation (3) and the radar cross section ffl! (II circuit (also the radar cross section σ calculated in 1 and other equipment (navigation equipment)
The mother aircraft height obtained through the interface circuit (lO) is input to the target identification circuit (6), and then the target identification circuit (6) is used to identify the targets.

For example, assume that missiles and aircraft are to be identified.

As mentioned above, the radar cross section of an aircraft is generally larger than that of a missile. Regarding the absolute losing streak, the maximum flight speed is lower for aircraft, and the maximum flight speed for Mi+/Ile is higher). Typically, the radar cross-sections and absolute velocities of missiles and aircraft lie in the ranges shown in FIG.

For example, when identifying missiles and aircraft using the identification boundary shown in the figure, two pieces of information are used: the radar cross section and the absolute speed, so the identification accuracy is higher than the identification based on the 1/-da cross section. good. Furthermore, since the flight speed range of missiles and airplanes changes depending on the altitude, in response to the mother aircraft counterfeit input from the interface circuit (IO),
By changing the identification boundary value of absolute velocity, highly accurate target identification becomes possible.

In the above example, the identification boundary value of the absolute speed was changed for each mother flight, but it is also possible to set the identification boundary value from the average flight possible speed range for each i1U2 and not use the mother aircraft height. It is possible. However, in this case, the identification performance becomes somewhat worse.

Furthermore, in the above embodiment, the absolute velocity was calculated using equation (3) considering a radar device that detects a target approaching from behind, but when considering a radar device that detects a target approaching from the front, If the absolute velocity is calculated using the following equation instead of equation (3), exactly the same effect of the invention can be obtained.

■A = ■8 - ■A/6 (4) Where, ■A: Absolute speed of target vR: 'Relative speed VA, 6 As above, according to the present invention, the type of target can be identified. As a method, we have adopted a configuration that uses not only the radar cross-sectional area of the target but also the absolute velocity of the target, so that it is possible to achieve high-precision targets without increasing the scale of the device in a wide-coverage radar system. 7.1' It has the effect of making identification possible.

[Brief explanation of drawings]

Fig. 451 is a block diagram of a conventional pulse radar radar installation, and Fig. 2 shows an aviation mode for detecting targets approaching from behind.
Fig. 283 is a block diagram of a conventional pulsed burder equipment that can identify targets with high precision even in non-scanning and wide coverage areas, and Fig. 4 is an explanatory diagram of the burr removal equipment according to the present invention. FIG. 5 is a block diagram of a pulsed Doppler radar device capable of high-accuracy target identification even in a non-driving wide area, and FIG. 5 is a conceptual diagram showing the target identification method of FIG. 4. In the figure, (1) is the antenna, (Ill, (21
1 is a monopulse antenna, (21, Q2i, (2 Kai (32) is a receiver, [31, (+3). (23), (331 is a range game), +4+,
Q4), +24), +34) are Doppler filters, (5) are radar cross section calculation circuits, (6) are target identification circuits, +7), (27+ are direction detection circuits, (8) are antenna gain calculation circuits, ( 9) is an absolute speed calculation circuit,
(io) is an interface circuit. Note that the same reference numerals in each figure indicate the same parts. Agent Masuo Oiwa Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A circuit that detects the distance to the target based on the signal received by the antenna, a circuit that detects the relative speed between the target and itself, a circuit that calculates the radar cross section from the relative speed and distance determined by these circuits, and the above-mentioned relative speed. A radar device comprising: a circuit that calculates the absolute speed of a target from its speed and its own speed; and a circuit that identifies the type of target from the radar cross-sectional area, absolute speed, and its own cylindrical degree.