JPH0226752B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to air traffic control equipment, and in particular to secondary radar (hereinafter referred to as SSR) in a radar control system.
The present invention relates to a transmitting device for suppressing side lobes in a system (referred to as ``transmitters'').

Conventionally, this type of secondary radar system uses a three-pulse SLS method to suppress side lobes, and an improved side lope suppression method to suppress false targets due to reflections in addition to the side lobes. The 3-pulse suppression method is ICAO
(International Civil Aviation Organization)
This is a well-known method stipulated in the recommendations and the Radio Law, and an improved side rope suppression method was also introduced in February 1973.
1975 IEICE Space Navigation Electronics Study Group Material SANE77 published by IEICE on March 24th
-31 “New technology in SSR” etc.

As is clear from the document, in the case of the improved side rope suppression method, in order to also transmit the first pulse (or P1 pulse) that should originally be transmitted from the interrogation antenna from the control antenna, the interrogation antenna The power radiated from the
30% reduction while increasing transbonder downtime.

Therefore, in practice, the use of the improved side rope should be kept to a minimum, and the present invention relates to switching between the 3-pulse side rope suppression method and the improved side rope suppression method.

A method shown in FIG. 1 has been proposed as a switching method between the 3-pulse sidelobe suppression method and the improved 3-pulse suppression method.

In FIG. 1, in the case of the 3-pulse SLS method, the switch 3 is switched to the circuit shown by the dotted line. In this state, the first and second signals output from the transmitter 1
and the third pulse (P1, P2, and P3) are divided into the first and third pulses P1, P3 and the second pulse P2 by the switch 2, and the pulses P1 and P3 are sent to the interrogation antenna (Fig. 2, 8, 9) or the pulse P2 is sent to the control antenna (see FIG. 2, 10).

In the case of the improved side rope suppression method, at the same time as the switch 3 is switched to the circuit shown by the solid line,
By the switching gate to the switching device 2, the entire power of the second pulse P2 is sent to the control antenna (see FIG. 3, 10), and half of the first pulse P1 is sent to the control antenna,
The remaining half is sent to the interrogation antenna through switch 4 (see Figure 3, 8 and 9). Third pulse P3
Like the first pulse P1, the entire power is sent to the switch 4 through the switch 3, but in order to match the power with the first pulse P1, half of the output is sent to the switch 4 through the switch 3.
(see Figure 3, 9).

As a result, the pulse P1, which is about half of the transmitter output,
P3 is sent to the interrogation antenna, and a pulse P1 with the same output as this and a pulse P2 with the same output as the transmitter are sent to the control antenna, which creates a directional antenna as the interrogation antenna and an omnidirectional antenna as the control antenna. The aerial allows for improved side rope suppression.

However, this method has the following drawbacks. In other words, in order to supply the P1 pulse to both the interrogation antenna output and the control antenna output in the switch 2, the switch 2
It is necessary to conduct in both directions for the input.
As a result, if the characteristic impedance of the circuit is Zo, the input impedance of the switch 2 is Zo/2, and the standing wave ratio in this case is 2. In other words,
Approximately 10% of the incident power returns to the input side as reflection and becomes a loss. Further, the generation of standing waves due to impedance mismatching causes unnecessary pressure to be applied to circuit components.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore, an object of the present invention is to provide a novel transmitting device that can eliminate the above-mentioned drawbacks of the prior art.

In order to achieve the above object, the transmitting device according to the present invention includes means for sending out a transmission pulse including a control pulse for sidelobe suppression, and a means for sending out a transmission pulse including a control pulse for sideloop suppression, and a means for separating the transmission pulse into output pulses to an interrogation antenna and a control antenna, respectively. 1 switching means, and a second switching means for switching to the 3-pulse sidelobe suppression method or the improved sideloop suppression method by bypassing the output pulse for the interrogation antenna to the interrogation antenna output or switching to the next power divider. , means for distributing the output signal from the second switching means into two systems and separating one into an interrogation antenna output and the other into a second interrogation pulse of the first interrogation pulse, the means By combining the first interrogation pulse from the first interrogation pulse and the control antenna output pulse from the first switching means by a half-wavelength synthesis circuit,
The present invention is characterized by effectively switching between the pulse sideloop suppression method and the improved sideloop suppression method.

That is, the present invention adds a power divider to the output of the switch 3 in order to solve the drawbacks caused by impedance mismatch and to switch the 3-pulse sidelobe suppression method to the improved 3-pulse sideloop suppression method. However, in this method, pulses P1 and P2 sent from the control antenna are combined by a half-wavelength combining circuit.

Next, a preferred embodiment of the present invention will be specifically described with reference to the drawings.

An embodiment of the present invention is shown in FIG.

An embodiment of the transmitting device according to the present invention is a transmitter 1
01, first switch 102, second switch 10
3, a third switch 105, a power divider 104, a modulator (switched gate generator) 106 and cables 107, 108 having integral multiples of two half wavelengths.

The transmitter 101 generates pulses P1, P2, and P3 including a control pulse P2 for sidelobe suppression. The switch 102 transmits the interrogation transmission pulse P.
1, P3 and a control pulse P2, and as shown in FIG.
send to When the 3-pulse sideloop suppression method is selected by the switching signal 116, the switch 103 is switched as shown by the dotted line, and as shown in FIG. Send to 111. On the other hand, the switching signal 11
6, when the improved sideloop suppression method is selected, pulses P1 and P3 are applied to the power divider 104 as shown in the solid line, and pulse P1 is switched as shown in FIG. , half of P3 is output 1 for interrogation antenna through switch 103.
11, and the other half is added to switch 105.

The switch 105 acts to switch to the pseudo load 109 via the switching gate 115 at the time of the pulse P3, so that the pulse P3 is consumed by the pseudo load 109. At the time of pulse P1, switch 105 is conductive so that pulse P1 is sent to control antenna output 113 as shown in FIG. The output side for the control antenna of the time odor switch 102 of the pulse P1 is the switching gate 1.
14 is in an open state, and a connection point 112 located at an integral multiple of a half wavelength from the output side is also in an open state. Therefore, from the switch 105
The total energy of P1 pulse is output 1 for control antenna.
Sent to 13th. On the other hand, during the pulse P2, the control antenna output side of the switching device 105 is in an open state, and the switching device 1 seen from the connection point 112
The impedance on the 05 side is infinite. Therefore, all of the energy of the P2 pulse from switch 102 is sent to control aerial output 113.

As explained above, the present invention can perform power distribution in the improved sideloop suppression method using a power divider with impedance matching, so power loss is small and there is no impedance mismatch. Circuit configuration becomes possible.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of a conventional transmitter, Figure 2 is a diagram showing the waveforms of the main parts in the case of the 3-pulse sideloop suppression method in Figure 1, and Figure 3 is an improved version of Figure 1. FIG. 4 is a block configuration diagram showing an embodiment of the transmitting device according to the present invention. FIG. FIG. 6 is a diagram showing waveforms of main parts in the case of the improved side lobe suppression method in FIG. 4. 1... Transmitter, 2... Transmission pulse switcher, 3...
...Circuit switch, 4...Transmission pulse switch, 5...
Pseudo load, 6...Switching gate generator, 101...
Transmitter, 102... Transmission pulse switch, 103...
...Circuit switcher, 104...Power divider, 105...
...Transmission pulse switcher, 106...Switching gate generator, 107, 108...Half wavelength synthesis circuit, 109
...Pseudo load, 110...Transmission pulse including control pulse for suppressing side ropes, 111...Output for interrogation antenna, 113...Output for control antenna.

Claims (1)

[Claims] 1 means for sending out a transmission pulse including a control pulse for sideloop suppression; a first switching means for separating the transmission pulse into output pulses for an interrogation antenna and a control antenna, respectively; a second switching means for switching to the three-pulse sidelobe suppression method or the improved sideloop suppression method by bypassing the power divider or switching to the next power divider; and an output signal from the second switching means to be divided into two systems. the first pulse from the separating means and the first pulse from the first switching means. A transmitting device characterized in that an improved side lobe suppression method of a three-pulse side lobe suppression method is effectively switched by combining output pulses for a control antenna with a half-wavelength combining circuit.