JPS58204381A - Automatic tracking device - Google Patents

Abstract

PURPOSE:To make phase of a sum signal and a difference signal coincide automatically, by detecting a phase difference of the sum signal and the difference signal by an error signal detecting loop consisting of a phase shifter, a 90 deg. phase shifter, a phase detecting circuit and an erro signal amplifier. CONSTITUTION:A phase shifter 9 has a function which is capable of varying the phase of an output of an IF amplifier 6b by external control voltage. Also, a 90 deg. phase shifter 10 has a function which is capable of changing the phase of an output of the phase shifter 9 by 90 deg.. An error signal amplifier 11 generates control voltage which is capable of varying the phase of the phase shifter 9 by amplifying an output of a phase detecting circuit 7b. Also, a terminal TP5 is an output terminal of the phase detecting circuit 7b. Accordingly, when an output phase difference of IF amplifiers 6a, 6b is denoted as DELTAtheta, the phase difference DELTAtheta is corrected automatically to ''0'' even if frequency of a carrier wave is varied, therefore, no influence is exerted even in case of a variation of frequency of the carrier wave.

Description

Detailed Description of the Invention This radar 8J4 relates to a tracking radar that can detect the elevation angle and azimuth of a target moving in space and automatically track it. A tracking bag that automatically matches the phase at the input end of the phase detection circuit f! i.

Conventionally, this type of device was shown in Figure 1. In the diagram, (1) is an antenna that can receive the reflected signal from the target, and (2) is the antenna that can receive the signal received by antenna (1) from antenna (1). It is a hybrid that has the function of being able to decompose into a sum signal and a difference signal depending on the angle at which the target is viewed. TP1 is the sum signal output terminal of the hybrid (2), and TP2 is the difference signal output terminal of the hybrid (2). (3) is a mixer that converts the Vi received signal to an intermediate frequency C or lower (abbreviated as IP); and (4) is a reference signal generator. (5) #'1
This is a phase corrector that can shift the phase of the reference signal from the reference signal generator (4). (6) It is an IP amplifier that has the function of amplifying the output of the U mixer (3) and the automatic gain adjustment (hereinafter abbreviated as AGO) to keep the amplitude to a constant level so that the amplified output does not change except for changes in angle. .

(7) is a phase detection circuit that detects the amplitude and phase difference of the IF amplifier (6) of the sum signal and difference signal. TP3 and TP4 are input terminals for the sum signal and difference signal of the phase detection circuit (7). (8) is an antenna drive circuit that amplifies the output of the phase detection circuit (7) and directs the antenna (1) at a predetermined angle.

Next, the operation will be explained. When the reflected wave from the target enters the antenna (1) as a received signal, it becomes an hybrid (2).
is decomposed into a sum signal and a difference signal by TPI and TP2
In each case, an output is obtained according to the angle of the target as seen from the antenna (1). A typical pattern of the output is shown in FIG. As you can see from this figure, the angle of the target and the antenna (1
) When the facing angles of antennas match, the sum signal becomes maximum and the difference signal becomes minimum, but when the angles of the target and antenna deviate, the sum signal becomes a combination of (+, -). This detects the angle of the target. The output from the hybrid (2) (TP1 and TP2 signals) is mixed with the reference signal from the reference signal generator (4) and the mixer (3a), (3N, converted into an IP double signal, and then sent to each IP amplifier) Amplified by (6a) and (6b) [phase detection circuit (7) K is supplied. Phase detection circuit (
If the output of 7) is v1, then generally V, = KAB residence Δθ
・・・・・・・・・・・・・・・(The output shown by 11 is obtained. Here, K is the phase detection circuit (7)
, the amplitude of AUTP3, B is the amplitude of TP4, and Δθ is the phase difference between the signals at TP3 and TP4F. Δ
θ is adjusted by a phase corrector (5) so that it becomes O (for example, by changing the length of the cable). It is called the VIF1 angle error signal and is 0 if the angles of n target and antenna match, but if they deviate, the output increases in proportion to the angle, and the polarity is determined by which side of the antenna axis the target is located.

A typical example thereof is shown in FIG. The antenna drive circuit (8) outputs this angular variation error V,'f! - Amplify and drive the servo system of the antenna (1) so that the 1-angle error output V becomes O. In this way, it is possible to detect the angular error for a target that is off the antenna axis and always direct the antenna in the direction of the target.

Since the conventional tracking device is configured as described above, it is necessary to correct the phase difference Δθ between the two input signals (TP3° and TP4 signals) of the phase detector (7) to O.
It is technically difficult to make the sum signal and the difference signal the same including the phase change of the IP amplifier including the 1AGO characteristic. In addition, there is the possibility that the phase may change due to changes in signal line length or circuit elements due to temperature changes, and it is technically difficult to make the phase changes of related components the same, including temperature changes. Ta.

This invention was made to improve these drawbacks, and the purpose of this invention is to eliminate the phase difference between the sum signal and the difference signal by automatically performing the problematic phase correction.The details of this invention are described below. I will explain about it.

FIG. 4 shows a specific example of this invention. In the figure, (1) to (4) and (6) to (8) are the same as in FIG. (9) This is a phase shifter that has the function of varying the phase of the output of the UIF angle (6b) using an external control voltage. It is a phase detector and αη phase detector circuit (
This error signal amplifier has the function of amplifying the output of 7b) and generating a control voltage that can vary the phase of the phase shifter (9). It is also the output terminal of the TP5 phase detection circuit (7b).

Next, the operation will be explained with reference to FIG. Vibrator 11 (
The outputs up to 2) are the same as in Figure 2, but the output of the reference signal generator (41) does not include the phase corrector (5) in Figure 1, so the output of the TF amplifiers (6a) and (6b) The output has a phase shift difference.The phase difference is △θ, the output of IP amplifier (6b) 'iAgi+1wt, the output of IF amplifier (6b) k
Let Bgjr+ (so t+Δθ). These are the amplitudes of the sum signal and difference signal depending on the relative positions of the A and B antennas and the target. When the phase shift angle of the phase shifter (9) is φ, the output of the phase shifter (9) is expressed as uB*(sot+Δθ+φ). Since the 90° phase shifter α1 further shifts the phase by 90°, its output (rl Bsln(w + +Δθ+φ+90
). The input of the phase detector (7b) is the above signal and I
Since the output of F amplifier (6a) is Aslnwt, if its output (signal of TP5) is V, then V, = KAB (△θ+φ+90°) K'AB due r△
θ1φ) ・・・・・・・・・・・・・・・
(21. IK' is determined by the phase angle of Δθ + φ. The phase shifter (91, 90° phase shifter αO1 phase detection circuit (7b), and error signal amplifier 0 A control loop is constructed so that the phase transition angle φ of the phase shifter (9) is varied when the value ■ is not Ov.
It is. Therefore, in order for (Equation 21 Eli■) to become OV, φ=-△θ and the output of phase shifter (9) (signal of TP4)
becomes Bstnwt. On the other hand, the signal of TP3 is AsfnW
t and the phase of the signals of TP3 and TP4 is output fVs, then △θ=0, so V3=KAB
・・・・・・・・・・・・・・・(3) (1
) and (3), as is clear from equation (3), there is no term for the phase difference Δθ. In the conventional tracking device, this △θ is the IP amplifier (6a).

(6b) Characteristic variations that were not sufficiently corrected due to temperature changes in the circuit elements can be automatically corrected by this invention.
= 0, which means that the drawbacks of the conventional system have been improved. In addition, in conventional devices, when the frequency of the carrier wave changes, the wavelength of the input signal applied to the mixer (3b) changes, so it was necessary to readjust it with the phase corrector (5), but in this invention, the frequency of the carrier wave changes [2 However, the phase shift difference △θ is automatically set to K.
Since it is corrected to O, it has the advantage that it has no effect on carrier wave frequency fluctuations.Using this, in order to avoid radio wave interference, it is possible to vary the carrier wave frequency so that the interference side cannot catch up ( It can also be used for fricage, asiatility functions).

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional tracking device, Figure 2 is a typical turn diagram of sum signals and difference signals, Figure 3 is a diagram showing typical angular variation error output characteristics, and Figure 4 is a diagram showing typical angular variation error output characteristics. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, (1) is an antenna, f2+
117t hybrid, (3) is mixer, (4) is reference signal generator, (5) is phase corrector, (6) is IP amplifier, (7) is phase detector, (8) is antenna drive section ,(
9) is a phase shifter, (10 is a 900 phase shifter. 0 is an error signal amplifier. Note) Parts corresponding to N- or Ike are indicated with the same number. Nobuo −

Claims (1)

[Claims] An antenna capable of receiving a reflected signal from a target and a received signal from the antenna are divided into a sum signal and a difference signal. a hybrid; a reference signal generator for generating a reference signal; mixing the reference signal generated from the reference signal generator with the output of the hybrid;2. A mixer for sum and difference signals that converts to an intermediate frequency, an intermediate frequency amplifier for sum and difference signals that amplifies the output of this mixer, and a phase detection that detects the phase of the output of the intermediate frequency amplifier for sum and difference signals. circuit, and amplify the output of this phase detection circuit; an antenna drive circuit that drives the antenna; a phase shifter that shifts the phase of the output of the intermediate frequency amplifier for the difference signal; and a total of 9 outputs of this phase shifter.
08 A 90° phase shifter that shifts the phase, a phase detection circuit that detects the phase of the output of this 90° phase shifter and the output of the sum signal intermediate frequency amplifier, and an error signal that amplifies the output of this phase detection circuit. The phase difference between the sum signal and the difference signal is detected by an error signal detection loop consisting of the above phase shifter, a 90° phase shifter 9 phase detection circuit, and an error signal amplifier, and the phases of the sum signal and the difference signal are matched. An automatic tracking device characterized in that it is configured to