JPS58201081A - Automatic phase balancing system of radar receiver - Google Patents

Abstract

PURPOSE:To respond sufficiently to the alteration of phase difference of every transmission pulse repeat cycle, by detecting the phase difference in a pilot pulse signal in every transmission pulse repeat cycle to determine a phase compensating value and constituting an open loop controlling circuit so that a prescribed control error is obtained. CONSTITUTION:Videos I and Q separated to orthogonal vectors I and Q are outputted by synchronous phase detectors 31 and 32. Phase detectors 35 and 36 use digital videos I and Q to perform the operation of tan<-1>Q/I to detect phases thetaA and thetaB, and a phase difference detector 37 performs the operation of thetaA-thetaB=PSI and outputs the phase difference PSI for the pilot pulse signal. A complex converter 38 converts the phase difference PSI to complex numbers of COSPSI and SINPSI and outputs them as phase compensating values while holding COSPSI and SINPSI. A phase shifter 39 performs the complex multiplication to shift the phase by components of the phase difference PSI, thus achieving the phase balance between systems A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to increasing the response speed of an automatic phase balance system of a radar receiver having two or more channels.

It is well known that three-dimensional radar equipment that detects the range, direction, and altitude of a target requires multiple reception channels, and phase balance between the reception channels is also required to detect the altitude. It is also well known that A conventional automatic phase balancing system for such a radar device is shown in FIG.

In the figure, (1) and (2) are antennas, (3) and (4)
is a directional coupler, (5) Fi transmission switch, (6) and (
7) RF amplifier, (8) and (9) are receiving mixers, (
10) is a CoHO generator, (11) is a local oscillator, (1
2) is a transmission mixer, (13) is a pulse modulator, (14)
) is a pulser, (15) is a power amplifier, (16) is a trigger generator, (20) is an automatic phase balancing circuit, a phase shifter (21), a phase difference detector (22), a sample holder (23) ) and a loop filter (24).

FIG. 2 is an explanatory diagram of the operation of FIG. 1.

For convenience of explanation, the number of reception channels in FIG. 1 is assumed to be two channels in the following description. Since the operations of the circuits other than the automatic phase balance circuit (2o) are generally well known, the explanation will be omitted, and only the injection of the pilot pulse signal and the operation of the automatic phase balance circuit (20) will be explained. .

First, regarding the injection of a pilot pulse signal, an RF pulse is generated every transmission pulse repetition period by a pulse modulator (13) during a radar idle time period determined by the radar device, and is then transmitted to a directional coupler (3). (4) at the same level and phase and is combined with the received signals received from antennas (1) and (2) (as shown in FIG. 2-a).

The received signal '8 including the pilot pulse signal is passed through a mixer (8
) and (9) as output F signals and supplied to the automatic phase balancing circuit (20).

In the automatic phase balance circuit (2o), the antenna (1) series is used as the reference channel, and the antenna (hereinafter referred to as A series), antenna (
The series 2) is defined as a phase-balanced channel (hereinafter referred to as the B system), and the phase difference between the A system and the B system is detected by a phase difference detector (23) (as shown in FIG. 2-b). The detected phase difference is sampled by the sample holder (24) only during the time period of the Tepirosort pulse signal, and the phase difference at that time is held until the arrival time of the next pilot pulse signal (as shown in FIG. 2-C). A loop filter (24) removes high frequency fluctuation components from the sampled and held output at a predetermined time constant, and outputs a phase compensation signal to the F phase shifter (21). The F system shifter (21) changes the amount of phase shift by voltage control, and shifts the phase according to the phase compensation signal from the loop filter (24) to achieve phase balance with the A system. be.

Here, this automatic balancing circuit (20) is an automatic control circuit using negative feedback as shown in Fig. 1, and the closed loop time constant is normally set to make the constituent circuit less susceptible to disturbances such as power fluctuations. It is common to set it to several cycles.

Because the conventional automatic phase balance system is configured as described above, when performing so-called frequency agility, which changes the transmission frequency every transmission pulse repetition period, the response speed of the automatic phase balance circuit is not fast enough, and the phase balance cannot be achieved. The drawback was that it could not be maintained.

The present invention has been made to eliminate such drawbacks, and detects the phase difference within the pilot pulse signal at each transmission pulse repetition period, determines the phase compensation value, and achieves a specified control error. By configuring an open-loose suppression circuit as described above, the present invention aims to provide a high-speed automatic phase balancing system that sufficiently responds to changes in phase difference for each transmission pulse repetition period.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, the common sauce part with FIG. 1 is omitted. (
30) is an automatic phase balancing circuit according to the present invention (31)
and (32) synchronous phase detector, (33) and (34) A
/D converter, (35) and (36) phase detector, (
Phase difference detector (37), complex converter (38), (39)
) phase shifter.

4 and 5 are explanatory diagrams of the operation of FIG. 3.

FIG. 3 shows an automatic phase balancing circuit between two receiving channels, similar to FIG. 1, in comparison with the conventional one. A system is the sequence received from antenna (1),
As in FIG. 1, system B is a system received by antenna (2). In addition, a synchronous phase detector (31) and (
32) is supplied from the eight CoHO generators (10), and other A/D
The timing required for converters (33), (34) etc. is provided by a trigger generator (16).

A-system engineering F signal '8 from in front of the receiver (supplied from terminal A)
The engineering F signal of system B (supplied from child B) is input to the automatic phase balancing circuit (30), and the synchronous phase detector (31) and (3
2) outputs E-video and Q-video separated into orthogonal vectors E and Q, respectively, as shown in FIG. 4, using the C0HO signal (supplied from terminal C). The A/D converters (33) and (34) sample and hold these processed and Q-videos, convert the analog signals to digital signals, and output them as digital and Q-videos. Phase detector (35
) and (36), from this digital video, t
A'n-1 (%) calculation is performed to detect phases θA and θB, respectively. In the phase difference detector (37), θA-θB
= ψ calculation is performed and the phase difference ψ is output for the pilot pulse signal. In the complex converter (38), the phase difference ψ is CO
Since S ψ and EI N ψ are complex, they are converted, and the next pilot pulse signal arrives after the time of the pilot pulse signal, so COS ψ and S N ψ are held and output as a phase compensation value. Phase shifter (39) Deke A/
By performing complex multiplication of the digital code and Q video of the D converter (34) and the multiplicative phase compensation values COS ψ and S process Nψ, the phase is shifted by the phase difference ψ, and phase balance between the A system and the B system can be achieved. Further, to explain the phase shifter (39) in detail, the phase shift function can be achieved by a complex multiplication circuit network represented by a circuit such as the one shown in FIG.

Now, let the phase of system A be θA, the phase of system B be θB, and θA=
If θB + ψ, then the B-system vector E, Q is given by the knee COS θB, Q, ==S, NθB. or,
When compensating the phase difference ψ for the B system, Equation (1) (2
).

Regarding vector e, cos (θB + ψ) = cos θB, CO8ψ−8 kN
θB, B engineering Nψ 11. ..., (1) Regarding vector Q, S engineering N (θB + ψ) = SINθB - CO8ψ + cosθ
B, S engineering Nψ ・1.・-(2) Figure 5 shows this formula (1)
, (2) using four multipliers, an adder, and a subtracter. In this way, the phase difference between channels is detected within the pilot pulse signal, and the phase difference is held as a phase compensation value until the arrival of the next cycle's pilot pulse signal to compensate, so the transmission pulse is repeated. It can follow the phase difference that changes every cycle.

In the above embodiment, an automatic phase balancing method using an open loop was explained, but it goes without saying that it can also be applied to an automatic phase balancing method using a feed pack method if the pulse width of the pilot/Yars signal can be wide. .

As described above, according to the present invention, a phase difference is detected within a pilot pulse signal, and the phase difference is held as a phase compensation value until the next period of the pilot pulse signal arrives for phase compensation. Therefore, even in the case of frequency agility in which the phase difference changes with each transmission pulse repetition period, there is an effect that phase balance between channels can be maintained.

(9)

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional automatic phase balancing system, and FIG. 2 is an explanatory diagram of the operation of the conventional system. FIG. 3 is an example of an embodiment of the automatic phase balance system according to the present invention, and FIGS. 4 and 5 are diagrams illustrating the operation of the system of the present invention. In the figure, (1) and (2) are antennas, (3) and (4)
is a directional coupler, (5) is a transmitter/receiver switch, (6) and (7)
is an RF amplifier, (8) and (9) are receive mixers, (10
) is the CoHO generator, (11) is the local oscillator, (12)
is a transmission mixer, (13) is a pulse modulator, (14) is a pulser, (15) is a power amplifier, (16) is an LD trigger generator, (20) is an automatic phase balance circuit, and is a mechanical F phase shifter. (21), phase difference detector (22), sample holder (
23) and a loop filter (24). In addition, (30) is an automatic phase balancing circuit, which includes synchronous phase detectors (31), (32), and an A/D converter (33).
), (34), phase detection.Things with a reference numeral in the figure indicate the same or equivalent (io) product. (11) Figure 1 Figure 2 Figure 3 Figure 4 Figure 2 Procedural amendment (voluntary) Mr. Commissioner of the Japan Patent Office 1, Indication of the case, Japanese Patent Application No. 57-87088 2,
Title of invention Automatic phase balancing method for radar receiver 3
, Representative Hitoshi Katayama (3) Revise Figure 6 as shown in the attached sheet. 7. List of attached categories (1) One document stating the corrected claims (2) At least one drawing showing the corrected Figure 5
As claimed in the above patent, pilot pulse signals of the same level and phase are injected from the input terminal of each receiver at each transmission pulse repetition period during the radar idle period of a radar device having a receiver with two or more channels. In the automatic phase balancing method of a radar receiver that performs inter-channel phase balancing at the receiver output end, the received IF signals of each of the n receiving channels are synchronously phase detected using the C0HO signal provided in the radar device, and the orthogonal vector I , Q, and an A/D of n m that converts the output of the synchronous phase detector from an analog signal to a digital signal.
From the digital video LQ of the converter and the output of each A/D converter, the phase value of the phase detector output of the receiving channel serves as the white reference for the n receiving channels. (n-1) phase difference detectors for detecting the difference between the phase value of the phase detector output of another receiving channel and the pilot pulse signal for each transmission pulse repetition period; and each phase difference detector. (n-1) complex converters that convert the phase difference into complementary numbers and update and output the phase compensation value every transmission pulse period, and the phase compensation value of each complex converter output and the corresponding reception channel. ■ A/D converter output of
, and a phase shifter that performs complex multiplication with the Q vector signal to compensate for the phase difference with the reference reception channel and achieve phase balance. The pilot pulse signal injected into the transmission pulse is used to detect the phase difference with the reference reception channel every transmission pulse repetition period, and the phase difference is used as a phase compensation value to shift the phase. An automatic phase balancing system for a radar receiver, which is characterized by being able to perform automatic phase balancing for each repetition cycle.

Claims (1)

[Claims] A pilot pulse signal of the same novel and same phase is injected from the input terminal of each receiver at each transmission pulse repetition period during the radar idle period of a radar device having receivers of two or more channels, In the automatic phase balancing method of a radar receiver that performs phase balancing between channels at each receiver output end, the receiver F signal of each of the n receiving channels is synchronously phase detected using the C0HO signal provided in the radar device, and then Mukaibun vector A/Q converts the outputs of n 4-phase phase detectors and synchronous phase detectors from sample-and-hold analog signals to digital signals, respectively.
A D converter, a digital video signal of each A/D converter output, n phase detectors that calculate the phase of each A/D converter output, and a reception signal that is the same standard for n reception channels. (n-1) detecting the difference between the phase value of the phase detector output of the channel and the phase value of the phase detector output of another receiving channel for each transmission pulse repetition period, based on the phase value of the phase detector output of the channel; (n-1) complex converters that convert the phase difference of each phase difference detector into a complementary number and update and output a phase compensation value every transmission pulse period; The phase compensation value of the complex converter output and the A of the corresponding receiving channel
/ A phase shifter performs complex multiplication with the output of the D converter and the Q vector signal to compensate for the phase difference with the reference reception channel and achieve phase balance. Using the pilot pulse signal injected into the receiver input terminal of Therefore, an automatic phase balancing method for a radar receiver is characterized in that automatic phase balancing can be performed for each transmission pulse repetition period.