JPS63266381A - Passive type ssr device - Google Patents

Abstract

PURPOSE:To improve the accuracy by discriminating that which corresponds to an interrogation radio wave of an SSR interrogator station from an intercepted response radio wave, and deriving a position of an aircraft, etc., from the time extending from sending-out of the interrogation ratio wave to reception of the response radio wave, and a position of the SSR station and a receiving point. CONSTITUTION:An antenna 11, a receiver 12 and a local oscillator 13 receive a response signal which is sent out of a transponder loaded on an aircraft. Antennas 21-23 intercept a response radio wave sent out of an SSR transponder against an interrogation radio wave transmitted from the respective interrogators of an SSR site. A CPU 70 executes an arithmetic processing corresponding to various data supplied from synchronizing signal generating circuits 41-43, correlating circuits 61-63 and a keyboard 71, and calculates a position of the aircraft.

Description

[Detailed description of the invention] [Industrial application field] The present invention does not have a transmitter itself, but is installed on an aircraft, etc. in response to SSR interrogation radio waves emitted from other SSR sites that have a transmitter. The present invention relates to a passive SSR device that detects the position of an aircraft by intercepting SSR response radio waves sent from an SSR transponder.

[Conventional technology] Currently, most aircraft are equipped with SSR transponders, which transmit information such as the altitude and status of the aircraft in response to interrogation radio waves from interrogators at SSR sites located at major airports and key air route points. It sends back a response radio wave containing various data shown. At each SSR site, by receiving this response radio wave, it is possible to measure the XY (or ρθ) coordinate position of the aircraft using radar, and by decoding the response radio wave, the code number, altitude, emergency, etc. of the aircraft can be determined. You can get flight information.

By the way, most of the aircraft that use small airports are SS.
I have an R transponder, but at small airports,
It is difficult to install a normal SSR device having an interrogator transmitter due to radio wave regulations and usage efficiency (equipment cost/effect). Therefore, conventionally, there has been a problem in that even if an aircraft receives interrogation radio waves from such an SSR interrogator and responds with a transponder, its position cannot be known outside of the interrogator base.

Therefore, as a device that can be installed at small airports etc. where it is difficult to deploy normal SSR devices, the
The direction of the aircraft is detected by intercepting response radio waves sent from the SR transponder, and the position of the aircraft is detected by detecting the propagation time from the time the interrogation radio wave is sent until the response radio wave is received. A passive SSR device has been proposed that is characterized by displaying
0-222782).

[Problems to be Solved by the Invention] However, in the passive SSR device described in Japanese Patent Application Laid-open No. 80-222782, the direction finding antenna for detecting the direction of the aircraft has a diameter of about 1 m and a height. Thirty vertical dipole elements are arranged on a cylindrical conductor approximately 30 cm long, and the entire device is large in size, as well as a circuit for distributing and combining the outputs of the vertical dipole elements and for relatively high-speed switching. The structure was complicated and the device as a whole was expensive. Furthermore, the direction finding accuracy of this direction finding antenna is about 0.5 degrees, and because the dipole element is switched at high speed, radio waves from nearby aircraft cannot be received, resulting in a dead zone. There were drawbacks.

The present invention has been made in view of the problems with the conventional type described above, and is capable of transmitting SSR of other stations without having its own transmitter.
To provide a passive SSR device which detects the position of an aircraft by receiving SsR response radio waves from an aircraft in response to interrogation radio waves without using a direction finding antenna, and which has a simpler circuit configuration, is smaller in size, is located lower, and has higher accuracy. With the goal.

[Means for solving the problems] The passive SSR device of the present invention
A means for intercepting response radio waves sent from the R transponder, and at least two SSRs from among the intercepted response radio waves.
Means for discriminating the interrogator station's interrogation radio waves, means for determining the propagation time of the discriminated response radio waves from the transmission of the interrogation radio waves to the reception of the response radio waves by 1TllI in total, and the total i11 data of these and the positions of each SSR station and reception point. The present invention is characterized by comprising means for calculating the position of the aircraft etc. as the intersection point of each elliptic curve based on.

[Operation] Referring to FIG. 2, the above propagation time is determined by the distance J from the SSR site that transmitted the interrogation radio wave, for example, the airport PH, to the aircraft S, and the distance J from the aircraft S to the receiving point PR.
Corresponds to the sum JH with R2.

In other words, the aircraft, etc. S has the SSR site PH and the reception point PR as its two focal points, and the distance Jo
It exists at one point on the ellipse EH whose major axis is H2). At the same time, the aircraft, etc. S is connected to another SSR site PN,
PY also exists on ellipses EN and EY determined by a similar relationship. Therefore, these ellipses EH, EN, EY
If the intersection point of , is calculated, this is the position of the aircraft, etc.

[Effects] According to the present invention, the direction finding antenna in a conventional passive SSR and the circuits for distribution, combination, switching, etc. associated with this antenna are not required, so the circuit configuration of the device can be simplified and the entire device can be made smaller. And it can be made cheaper. Therefore, it is possible not only to monitor aircraft on land but also to install it on an aircraft. Radars currently installed on aircraft can only monitor a relatively narrow area in front of the aircraft, but the device of the present invention can virtually monitor 380' and is highly effective in preventing near misses. In addition, by analyzing the code of the response signal, it is possible to know the altitude and type (military, civilian, airline) of other aircraft.

In addition, in the device of the present invention, by targeting multiple interrogators and improving the distance detection accuracy, the accuracy of position detection of aircraft etc. can be reduced to about 0. .5
It is possible to improve by more than the equivalent degree.

[Example code] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 shows the configuration of a passive SSR device according to an embodiment of the present invention. The device in the figure is an omnidirectional antenna 11.1.
090MHz receiver 12, local oscillator 13, parabolic antenna 21.22.21.103103O receiver 31
, 32.33, synchronization signal generation circuit 41.42.43, data detection circuit 51.52.53, correlation circuit et, 82
．． ea and a central processing unit (CPU) To.

The antenna IL receiver 12 and the local oscillator 13 are for receiving a response signal (1090 MHz) sent from a transponder mounted on the aircraft S (FIG. 2).

antenna 21.22.23, receiver 31.32.33,
Synchronous signal generation circuit 41, 42, 43, data detection circuit 5
1.52°53 and correlation circuit 61.62. as is
One is provided corresponding to each of the three SSR sites PH, PN, and PY (Fig. 2).

The antenna 21 (22, 23) is connected to the SSR site PH (
PN, PY), and the rotating antenna of the inkrogator transmitter of the SSR site PH (PN, PY) faces the PR of this device every 3 to several seconds. During a period determined by the beam width of the SSR antenna, a burst signal consisting of several interrogation signals IO to IO is received.

Receiver a1 (32, 33) uses this antenna 21 (22
23) is amplified and supplied to the synchronization signal generation circuit 41 (42, 43).

On the SSR site PH (PN, PY), 20 or 4
The interrogation signal is sent out at a predetermined period of 50 Hz.

The synchronization signal generation circuit 41 (42, 43) generates a pulse TRGH (
TRGN, TRGY). Each circuit 41 (42
, 43) are not shown in detail, but for example,
-Similar to what is described in Publication 222782
The interrogator transmitter of the R site PH (PN, PY) generates the interrogation signal at the above-mentioned predetermined period by using a voltage-controlled crystal oscillator having a natural frequency equivalent to that of the reference clock oscillator, and the rotation of the interrogator transmitter. The receiver 81 receives the antenna near the point where it faces each other every rotation.
It can be constructed with a synchronization circuit that synchronizes the voltage-controlled crystal oscillator including the phase using a burst signal of several IO to IO interrogation signals outputted from (82, 33). In addition, this synchronization signal generation circuit 4■ (42
, 41) determines the mode MODE of the interrogation signal and sends it to the CPU 70.

The data detection circuit 51 (52, 51) receives the synchronization pulse TRGH (TRGN) from the output signal of the receiver 12.

the reception timing of the response signal based on TRGY);
In other words, the above inquiry signal is the SSR site PH (PN, PY
), the SSR site PH (
The distance Un (JN, JY) from the aircraft S (PN, PY) to the device ps via the aircraft S is detected, and the code C0DE carried in the response signal is extracted by detecting the output signal.

The transmission cycle of the interrogation radio waves is 5 mS at the longest, and the amount of movement of the aircraft S during this period is approximately 1 even at 1000 km/h.
．． It is 4m. Therefore, the propagation time, ie, the distance JH, of the response radio waves for several consecutive interrogation radio waves transmitted from the same SSR site is approximately constant.

The correlation circuit 61 (82, 63) calculates the distance JR (JN
.

jy) are several consecutive synchronization pulses TRGH (TRGN
, TRGY), which is almost constant for SSR
It is distinguished as a response signal to the interrogation signal sent from the site PH (PN, PY), and the reception timing (distance) and code data C0DE of this response signal are sent to the CPU 70.
Send to.

The CPU 70 is composed of a microprocessor, etc.
Synchronous signal generation circuit 41.42.4B, correlation circuit 61°6
It executes arithmetic processing according to various data supplied from 2, 03 and the keyboard 71. For example, the altitude information (mode C) and status response (mode A) of the aircraft S may be detected based on the mode data MODE and code data, or each SSR site PH may be detected.

Distance (reception timing) data JH for each PN and PY,
jN, Jy and each SSR site PH, PN.

The position of the aircraft S is calculated based on PY and the position of the device PS, and a display output signal is created based on these data and sent to the display 72.

Furthermore, position information of the aircraft within a certain period of time, ie, the trajectory, is stored.

The display 72 includes a CRT, video RAM, map signal ROM, etc., and displays maps, aircraft positions, flight numbers, etc. within the detection range of this device based on the display output signal from the CPU 70 and the map signal from the map signal ROM. Display aircraft information.

[Modifications of Embodiments] The present invention is not limited to the above embodiments, but can be implemented with appropriate modifications. For example, the interrogation signal may include mode A1 for inquiring the status of the aircraft and mode C for inquiring the altitude of the aircraft, as described above.
There is a transmission format of the interrogation signal for each SSR site PH and PN.

For each PY...AAA...or...AACA
AC... is set in advance. Therefore, by using not only the reception timing data of the response signal but also the arrangement of the decoding data of the received response signal as judgment materials in the correlation circuit or CPU, the SSR site that is the source of the interrogation radio wave can be discriminated more reliably. be able to. Furthermore, even if a plurality of aircraft exist within the detection range of this device, the aircraft from which each response radio wave is sent can be more reliably identified by the decoding data of the response signals.

Furthermore, in the above embodiment, the predetermined SSR site is
Although the case where two predetermined SSR sites are set has been described, it is also possible to set two predetermined SSR sites. In this case, the position of the aircraft to be detected is determined at two points as the intersections of two ellipses, but for example, the operator of the passive SSR device intercepts communication with the aircraft control tower and determines the approximate position of the aircraft at a certain point in time. All you have to do is choose one based on a rational judgment, such as knowing the following, and then use the device to track the wake and make a decision.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a passive SSR device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operating principle of the present invention. 11: Omnidirectional antenna, I2: Response signal receiver, 21, 22.23: Parabolic antenna, 31, 32.3
3: Interrogation signal receiver, 41, 42.43: Synchronization signal generation circuit, 51, 52.5
3: Data detection circuit, 81, 82.83: Correlation circuit, 70: CPU.

Claims (1)

[Scope of Claims] 1. Means for intercepting response radio waves sent from an SSR transponder in response to interrogation radio waves transmitted from interrogators of each of a plurality of predetermined SSR sites; Means for discriminating question radio waves, means for detecting the propagation time from when the interrogation radio wave is transmitted from each predetermined SSR site until receiving the response radio wave thereto, and detecting the propagation time and the interrogation of each predetermined SSR site. Passive type S characterized by comprising means for calculating the position of the transponder based on the position of the radio wave transmission point and the position of the response radio wave reception point.
SR device. 2. A synchronization signal generation circuit that corresponds to each of the predetermined SSR sites and generates a signal synchronized with the interrogation radio wave transmitted from the SSR site, and a timing detection circuit that measures the reception timing of each response radio wave based on the synchronization signal. The passive type according to claim 1, comprising: a circuit; and a correlation circuit that discriminates a response radio wave repeatedly received at a predetermined frequency or more within a predetermined timing deviation as a response radio wave to an interrogation radio wave transmitted from the SSR site. SSR device. 3. The passive type according to claim 2, wherein the correlation circuit outputs, as the propagation time, the reception timing of a response radio wave discriminated as a response radio wave from a predetermined SSR site among the outputs of the timing detection circuit. SSR
Device.