JPH09171074A - Secondary surveillance radar apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a secondary surveillance radar apparatus by which a response signal can be decided even in a garble state. SOLUTION: A response signal which is transmitted from an object to be monitored is received by an antenna 1. The received response signal is sent to a receiver 30, it is purified and processed, and it is divided into two systems by a power distributor 8. On the other hand, the phase difference of a constituent pulse signal is detected by a phase detector 1, the magnitude of the detected phase difference and a prescribed value are compared by a phase-difference comparator 13, and the singularity of the object, to be monitored, as the transmitting source of the received response signal is inspected on the basis of a compared result. A response signal without singularity is regarded as a separation signal by a degarble processor 14. The response signal, on the other side, which is passed through a log IF amplification detector 11 and a target detector 15 is output from the degarble processor 14, and it is separated and decoded by using a separation-signal-code decoder 16 so as to be output via a target-data generator 17.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary surveillance radar device (hereinafter referred to as SSR / Secondary Surveillance Radar), and more particularly to a secondary surveillance radar device capable of measuring the phase in a response signal pulse.

[0001]

2. Description of the Related Art Conventionally, the SSR according to the present invention is emitted from itself, whereas other general radars use the transmitted radio wave emitted from itself and the reflected radio wave reflected from a target object. The questioned radio wave is received by a target object such as an aircraft, and the aircraft automatically responds to the flight information of the aircraft. This response information is received by the SSR, and the received information is highly reliable and is effectively used on the ground for air traffic control (ATC) and the like.

A configuration example of a conventional SSR is shown in FIG. 4 as a functional configuration block diagram. This SSR is an antenna 10
1, circulator 102, transmitter 12
0, a receiver 130, and a target detection device 140.

The SSR constructed as above is based on the transmitter 12
0, the interrogation radio wave is emitted to the aircraft via the circulator 102 and the antenna 101. In response to this inquiry radio wave, the antenna received the response signal returned from the aircraft,
The received signal is transmitted to the receiver 130 via the circulator 102.
Passed to Response signal pulses from the aircraft (hereinafter referred to as SSR video) received and processed by the receiver 130 are input to the target detection device 140, and the target is determined from the pulse intervals of the SSR video.

SSR video has two framing pulses (hereinafter 2FP) and 13 signal pulses (hereinafter C).
So called 12 bit
Is the code signal of. 2FP interval is 20.3μs, 2
The FPs are set as CP regions at equal intervals of 1.45 μs, and one data is formed. An example of the structure of SSR video is shown in FIG. 1 bit is 14 bits of the above 2FP and 12CP
The response signal of one hit is received for one question. The response signal of the SSR is usually 10 to 30 hits.

[0005]

However, in this conventional SSR device, the CP is detected only from the position of the SSR video.
In the state where two or more aircraft are close to each other (hereinafter referred to as a gable state), the two response signals overlap each other, and the received signal becomes a combined CP signal. In this garbled state, the response signal is as shown in FIG.
When overlapped as shown in, the first CP and the second C
The received signal of SSR overlapping P is a combined signal as shown in FIG.

In the conventional SSR which decodes only the CP configuration of SSR video, the first and second CPs of the composite signal cannot be separated. Therefore, in the garbled state, only the target position is detected to prevent erroneous decoding, and CP is not decoded. When the CP is forced to be decrypted by changing the conventional configuration, the CP is erroneously decrypted, and the reliability of the received information is lowered,
It involves the problem of confusing air traffic control and hindering safety management.

The above-mentioned duplication of the SSR video is a phenomenon that theoretically does not occur unless the target aircraft is approached. The above-mentioned phenomenon is a phenomenon that can sufficiently occur in the recent widespread use of aircraft and frequent take-off and landing. Correct decoding of the superimposed SSR video is also required from the security management of air traffic control.

It is an object of the present invention to provide a secondary surveillance radar device capable of decoding a response signal even in a gable state.

[0009]

In order to achieve the above object, the secondary surveillance radar device of the present invention converts a pulse-modulated high frequency signal, which is a response signal from a target, into an intermediate frequency, and converts it. Phase difference detection means for detecting the phase difference between the carrier wave of the response signal and the oscillation signal from the oscillator provided therein, and determination for determining the target garbled state based on the phase difference detected by the phase difference detection means And means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a secondary surveillance radar device according to the present invention will now be described in detail with reference to the accompanying drawings. Referring to FIG. 1, an embodiment of a secondary surveillance radar device of the present invention is shown as a functional block diagram.

The SSR device of this embodiment includes an antenna 1 as a radio wave transmitting / receiving unit, a circulator 2 for switching connection between a transmission signal and a reception signal, a transmitter 20 as a transmission radio wave generating unit, and a reception signal. 30 which is a processing unit of the target detection apparatus 40 which is a decoding unit of a received signal
And is configured. SSR constructed by the above
The transmitter 20, the receiver 30, and the target detection device 40 of
Further, it is subdivided as follows.

The transmitter 20 is composed of an exciter 4 that oscillates a signal for transmission and a power amplifier 3 that amplifies the signal oscillated by the exciter 4 into a transmission signal. Power amplifier 3
Is output from the antenna 1 via the circulator 2 as an interrogation signal. Further, the oscillation signal of the exciter 4 is output not only to the power amplifier 3 but also to the mixing and IF amplifier 7 which is a component of the receiver 30.

The receiver 30 includes an amplifier 5 for amplifying a received signal, a band pass filter 6 for refining the received signal, a mixing and IF amplifier 7 for removing a carrier and amplifying the signal, and a power distributor for distributing the signal into two. 8, used for phase detection 6
Oscillator 9 for oscillating 0 MHz signal, phase detector 1
0, and a log IF amplification detector 11.

In the receiver 30 having the above-mentioned configuration, mainly the refining / amplifying / inspecting preparation processing of the code signal which is the received signal is performed. The 60 MHz signal oscillated by the oscillator 9 is a reference signal for detecting the garbled state. With this reference signal, the phase of the pulse of the purified and amplified code signal is
It is detected by the phase detector 10.

The target detecting device 40 includes an A / D converter 12 which is an analog / digital signal converter and a phase difference comparator 1.
3, degarble processor 14 for releasing the gable state, target detector 15, code decoder 16, target data generator 1
7.

Target detection device 40 constructed as described above
Then, the gable state is detected and released, and the code data is decoded. The code signal detected by the receiver 30 in the preceding stage is compared in phase by digital numerical values. As described above, the regular 1-word code data is composed of 20.3 μs between 2FP and 1.45 μs between CPs. The received code is compared and checked based on the standard structure of this data.

SSR composed of the above-mentioned components
Transmits a transmission signal from a transmitter including the power amplifier 3 and the exciter 4 to the aircraft as an interrogation signal via the antenna 1. The response signal from the aircraft is received by the antenna 1. These response signals (see FIG. 2) are decoded through the amplifier 5, bandpass filter 6, mixing and IF amplifier 7.

The decoded signal is distributed by the power distributor 8, one of which is guided to the log IF amplification detector 11 and SS
The R video is sent to the target detector 15 of the target detection device 40. The other is guided to the phase detector 10 to perform phase detection with the 60 MHz reference signal of the oscillator 9 which is the reference signal for phase detection, and the phase detection signal is output to the target detection device 40.

An example of the above phase detection is shown in FIG. 2A is a response signal of the first device, FIG. 2B is a response signal of the second device, and FIG. 2C is a reception signal received by the SSR. The combined signal of FIG. 2C, which has been subjected to the above-mentioned purification / amplification / demodulation processing, is subjected to phase detection based on the reference signal of 60 MHz. FIG. 2D shows an output example of the phase detection signal.

The phase detection signal output from the receiver 30 is supplied to the A / D converter 12 of the target detecting device 40. The A / D converter 12 A / D-converts the phase detection signal for each response pulse, and the phase detection signal that is a digital value is supplied to the phase difference comparator 13.

The phase difference comparator 13, as shown in FIG.
The amplitudes of the digital values of the phase detection signals are compared to determine the three states of the pulse of the first machine, the pulse of the second machine, and the overlapped pulse. An example of this determination method will be described below with reference to FIG.

The initial value of the first phase detection signal is the amplitude value of the pulse number (1) (hereinafter referred to as A). The initial value of the second phase detection signal is the amplitude value of the pulse number (9) (hereinafter referred to as B).

The pulse numbers (2) and (4) of the phase detection signal are different from the values of A and B (hereinafter referred to as A and B) because the pulses are overlapped. From the above conditions, next, the initial value A1 of the first machine and the initial value B1 of the second machine are compared with the values of the pulse numbers (2) to (8). If it is a pulse and coincides with B1, 2
Judge as the pulse of the plane. Furthermore, if both A1 and B1 do not match (pulse number (2) and pulse number (4)), both SS of the first and second units
It is determined that the R video exists, that is, it is in the garbled state. Next, the garble processor 14 separates the response signals of the two machines that are in the garble state from the determination result, and the separated signals are supplied to the code decoder 16.

The code decoder 16 sequentially performs correlation processing between the response signal separated in the previous section and the next received response signal to improve the reliability of code decoding and the target detector 1
The direction and distance information of the aircraft detected in 5 is added to the code decoding result. The target data generator 17 edits and outputs the information from the code decoder 16 as target data for output to an external device.

As described above, according to the present invention, the phase difference of carrier waves for each pulse of the response signal is detected, and the presence or absence of overlap of the response signal for each pulse is detected using the detected phase difference.
The response signal can be separated and decoded from the detection result.

Although the above embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, the reference signal for phase detection is 60M
Not limited to Hz.

[0027]

As is apparent from the above description, the secondary surveillance radar device of the present invention receives the response signal transmitted from the monitored object and detects the phase difference between the pulse signals forming the response signal. Then, the magnitude of the detected phase difference is compared with a predetermined value, and it is possible to know the unity of the monitoring body which is the transmission source of the response signal received based on the comparison result. Therefore, it becomes possible to separate the composite response signals transmitted from the plurality of monitored objects by using the phase difference to form a single response signal.

[Brief description of the drawings]

FIG. 1 is a circuit configuration block diagram showing an embodiment of a secondary surveillance radar device of the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment of FIG. 1;

FIG. 3 is a timing chart for explaining the operation of the embodiment of FIG. 1;

FIG. 4 is a circuit block diagram showing a configuration example of a conventional secondary surveillance radar device.

[Explanation of symbols]

 1 Antenna 2 Circulator 3 Power amplifier 4 Exciter 5 Amplifier 6 Bandpass filter 7 Mixing and IF amplifier 8 Power distributor 9 Oscillator 10 Phase detector 11 log IF amplification detector 12 A / D converter 13 Phase difference comparator 14 Deguable Processor 15 Target detector 16 Code decoder 17 Target data generator 20 Transmitter 30 Receiver 40 Target detector

Claims (4)

[Claims] 1. A unit for converting a pulse-modulated high-frequency signal, which is a response signal from a target, into an intermediate frequency, and detecting a phase difference between a carrier wave of the converted response signal and an oscillation signal from an internal oscillator. A secondary surveillance radar apparatus comprising: a phase difference detecting means; and a judging means for judging a target gable state based on the phase difference detected by the phase difference detecting means. 2. When the determination means determines that the garble state is present, the garble state is at least 2.
2. The secondary surveillance radar device according to claim 1, further comprising degarble processing means for separating response signals from one target. 3. The secondary surveillance radar apparatus according to claim 2, further comprising an analysis unit that performs code analysis of the response signal separated by the degarble processing unit. 4. A means for receiving a response signal transmitted from a monitored object, and a means for detecting a phase difference between a carrier wave in a pulse signal forming the response signal and an oscillation signal of an oscillator included in the receiver. Means for comparing the magnitude of the phase difference with a predetermined value, and detecting the superposition state of the response signal based on the comparison result, and determining the unity of the monitoring body which is the transmission source of the response signal. A secondary surveillance radar device characterized by performing.