JPS636700Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for correcting quadrant error in a direction finder which detects the arrival direction of radio waves by receiving them with two sets of antennas orthogonal to each other.

In direction finders that detect the direction of arrival of radio waves using mutually orthogonal loop antennas or a pair of vertical antennas arranged orthogonally to each other, direction finders detect the direction of arrival of radio waves. When installed, the incoming radio waves are disturbed by the ship's hull, causing an error in the detected direction of arrival. This varies depending on the installation situation, but when the error is measured over 360 degrees around the installed direction finder antenna, the error component becomes zero every 90 degrees.The so-called quadrant error is relatively large. appear.

In order to correct such errors, in the past, coils were inserted in series or parallel to the receiving sections of the two antenna systems, and the magnitude of the received output of the two systems was set as an appropriate value and divided into four quadrants. I tried to minimize the error. According to such a correction means, when detecting the arrival direction of a beacon radio wave, there is no problem because the direction finding operation is performed for radio waves in a predetermined frequency band, and the quadrant error is suppressed quite well. be able to. However, for example, the frequency bands for ship communication are 1.6MHz, 3MHz,
Various types such as 4MHz, 8MHz, 12MHz, etc. are used, and it is difficult to correct the quadrant error for all these frequency bands.
In other words, when an inductance element is inserted into the receiving circuit of an antenna in this way, the inductance element not only changes the amplitude of the output, but also changes the phase characteristics, resulting in a phase shift between the received signal outputs of the two systems. This results in the inability to perform correct direction finding.

The object of this invention is to provide a quadrant error correction device that can correct quadrant errors over a relatively wide frequency band.

According to this invention, a variable amplitude adjuster is connected to two antennas for direction finding, and the variable amplitude adjuster can adjust the amplitude, but the phase characteristics do not change by adjusting the amplitude. The quadrant error is corrected by adjusting this variable amplitude adjuster.

Hereinafter, an embodiment of the quadrant error correction device according to this invention will be described with reference to the drawings. As shown in the figure, for example, the loop antennas 11 and 12 are arranged so that their loop planes are actually orthogonal, so that they can receive incoming radio waves as two mutually orthogonal components. These two sets of antennas 11,1
2, the received output is supplied to a receiving device 13, and the upper part in the figure is a quadrant error correction device 14 for receiving so-called beacon radio waves, and the lower part in the figure is for marine radio waves, i.e. This is a quadrant error correction device 15 when receiving radio waves for ship communication. These are the loop antenna 11,
Switch 16 and 17 to connect to receiver 12, and switch 18 and 19 to connect receiver 1.
Switch to 3 and connect. In the figure, switches 16 to 19 are in a connected state when receiving beacon radio waves. That is, these switches 16 and 17 are connected to the beacon radio wave error correction device 14 through input transformers 21 and 22, respectively. The output sides of these input transformers 21 and 22 can be selectively connected to correction circuits 24 and 25 and a direct passage 26 through a slide switch 23. In the figure, the slide switch 23 is the input transformer 21.
is connected to the correction circuits 24 and 25, and the input transformer 22 is connected to the passage 26. By turning off the switches 27 and 28, the correction circuit 24 converts the parallel circuits 31 and 3 of capacitors and coils into parallel circuits 31 and 3.
2 can be inserted in series one by one. Similarly, the correction circuit 25 is connected to the switch 3.
By turning off circuits 3 and 34, parallel circuits 35 and 36 of capacitors and coils can be inserted in series independently. Furthermore, by controlling a plurality of switches 37 provided between the output sides of the correction circuits 24 and 25, one of the taps of the coil 38 is selectively connected, and the correction circuit 2
Any part of the coil 38 can be connected between the output sides of the coils 4 and 25. The slide switch 39 switches between the signal taken out by the tapped coil 38 and the switch 37 and the signal from the passage 26, and the changeover switches 18, 19
supply to.

The correction device 14 for this beacon radio wave has been used in the past, and includes switches 27, 28, 33, 34 and 37 are selectively controlled, and the slide switches 23 and 39 are further controlled to reduce the quadrant error.

The quadrant error correction device 15 according to this invention corrects the quadrant error for incoming radio waves over a wide band such as radio waves for ship communication.
2 are connected to input transformers 41 and 42, and the output sides of the input transformers 41 and 42 are respectively connected to push-pull amplitude circuits 43 and 44 using transistors as amplifying elements. Push-pull amplitude circuit 43,
44 output transformers 45 and 46 are connected to variable resistance attenuation circuits 47 and 48, respectively. Each output of the resistive damping circuits 47, 48 is switched connected to a switch 19, 18 so that it can be connected to the receiver 13. The push-pull amplifier circuit 43, variable resistance attenuation circuit 47, push-pull amplifier circuit 44, and variable resistance attenuation circuit 48 have the same amplitude and phase characteristics.
The configuration is such that even if 7 and 48 are adjusted, their phase characteristics do not change.

To perform the correction by the quadrant error correction device 15, first set the resistance attenuation circuits 47 and 48 to the same amount of attenuation, so that the loop antennas 11 and 1
The two paths from 2 to the receiver 13 are assumed to have exactly the same amplitude and phase characteristics. Of course, in this case, the switches 16, 17, 18, 19 are each corrected by the correction device 15.
Switch to the side. In this state, the goniometer in the receiver 13 is controlled to detect an error with respect to the direction of arrival, and the variable attenuation circuit 4
7, 48, or both to minimize the quadrant error.

In this way, the quadrant error can be corrected, but in this case, in the receiving system for the two loop antennas, the attenuation circuits 47, 48
Since the phase characteristics are not affected even when adjusting The error correction function operates effectively. In particular, by combining a push-pull amplifier and a variable resistance attenuation circuit as an amplitude adjuster as in this example, characteristics with good linearity without cross-modulation can be obtained over a wide band. Also, amplifier 4
By using antennas 3 and 44, the distance between the antenna and the receiver can be increased.

The variable attenuation circuits 47 and 48 not only adjust the received signal levels in the two antenna systems, but also adjust the resistance values of the emitter resistors or base bias resistors of the transistors serving as the amplification elements of the push-pull amplifiers 43 and 44. However, the quadrant error may be corrected by adjusting the gain of the amplifier. Furthermore, as the direction finding antenna, not only a loop antenna but also an adkotok antenna may be used. Furthermore, in addition to inputting these two antenna systems into a goniometer, combining them, taking out the output as one system, and supplying it to the receiver, it is also possible to input the outputs of the two antenna systems to the receiving circuits of the two systems. The output may be supplied to a vector indicator.

[Brief explanation of drawings]

The figure is a connection diagram showing an example of a quadrant error correction device for a direction finder according to this invention. 11, 12: loop antenna, 13: receiver,
14: Quadrant error correction device for beacon, 15: Quadrant error correction device according to this invention, 43, 44:
Push-pull amplifier, 47, 48: variable resistance attenuation circuit.

Claims (1)

[Scope of utility model registration request] In a direction finder using a direction finding antenna device consisting of two sets of antennas that receive two components orthogonal to each other with respect to the direction of arrival, the phase characteristics are the same between the two sets of antennas and the receiver. and a variable amplitude adjuster capable of adjusting the amplitude so that the phase characteristics do not change due to the amplitude adjustment is inserted, and each of these variable amplitude adjusters is connected to the antenna, respectively. It consists of an input transformer, a push-pull amplifier circuit connected to the output side of the input transformer and using a transistor as an amplifying element, and a variable resistance attenuation circuit connected to the output transformer of the push-pull amplifier circuit. A quadrant error correction device for a direction finder, which is capable of correcting a quadrant error by adjusting the device.