JP2660695B2 - Passive SSR device - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention does not have a transmitter, but is mounted on an aircraft or the like in response to an SSR interrogation radio wave emitted from another SSR site having a transmitter. The present invention relates to a passive SSR device that detects a position of an aircraft or the like by intercepting an SSR response radio wave transmitted from an SSR transponder. [Prior art] Currently, most aircraft are equipped with SSR transponders, and the altitude and status of aircraft are monitored in response to interrogators from interrogators at each SSR site located at major airports and major air routes. A response radio wave carrying various data shown is returned. Each SSR site can receive the response radio wave and measure the XY (or ρθ) coordinate position of the aircraft by radar, and decode the response radio wave to determine the code number, altitude, emergency, etc. of the aircraft. You can get flight information. By the way, most aircraft that use small airports are SS
I have an R transponder, but at small airports,
It is difficult to arrange a normal SSR device having an interrogator transmitter in terms of radio wave regulation and utilization efficiency (equipment cost / effect). Therefore, conventionally, such SS
Even an aircraft that receives the interrogator interrogator's interrogation radio wave and responds with a transponder has the disadvantage that its position cannot be known except at the interrogator base. Therefore, as a device that can be placed at small airports, etc. where it is difficult to deploy a normal SSR device, the SSR mounted on the aircraft in response to the interrogator interrogator interrogation radio wave at a predetermined SSR site
Detects and displays the position of the aircraft by intercepting the response radio waves transmitted from the transponder and detecting the direction of the aircraft, and detecting the propagation time from the transmission of the interrogation radio waves to the reception of the response radio waves. There has been proposed a passive type SSR device characterized in that
No. 2). [Problems to be Solved by the Invention] However, the passive SSR device described in Japanese Patent Application Laid-Open No. 60-222782 has a direction detecting antenna for detecting the direction of an aircraft, for example, having a diameter of about 1 m and a height of about 1 m. A 30-cm cylindrical conductor with 30 vertical dipole elements arranged.The entire device is large, and the circuit configuration for distributing and combining the outputs of the vertical dipole elements and switching at relatively high speed is provided. It was complicated and expensive as a whole device. Furthermore, the direction detection accuracy of this direction detection antenna is about 0.5 mm, and since the dipole element is switched at a high speed, there is a drawback that a response zone from the aircraft at a short distance cannot be received and a dead zone occurs. Was. Japanese Patent Application Laid-Open No. 53-99790 discloses a conventional technique in which a so-called omnidirectional sidelobe suppression is performed when a directional interrogation antenna (rotating antenna) is oriented in a predetermined direction, for example, a north direction in an interrogator (interrogator). The reference pulse is transmitted from the control antenna, and the time at which the interrogating antenna receives the interrogation radio wave when the interrogation antenna is turned to the direction of the own device based on the reception time of the reference pulse is received, and the interrogated further rotated. A method is described in which a solid angle (a solid angle in anticipation of the own device and the target device from the interrogator) θ is obtained from a relative relationship with the time when the antenna is received via the target device. However, this method has a disadvantage that the interrogator on the ground also needs a reference pulse transmitting device, and the existing ground equipment needs to be retrofitted. The present invention has been made in view of the above-described problems in the conventional form, and does not have a transmitter itself, and
SSR of other stations without remodeling SSR interrogator equipment
It also receives the SSR response radio wave from the aircraft in response to the interrogation radio wave and detects the position of the aircraft, more simple circuit configuration, small size,
It is an object of the present invention to provide an inexpensive and highly accurate passive SSR device. [Means for Solving the Problems] The passive SSR device of the present invention is a means for intercepting a response radio wave transmitted from an SSR transponder mounted on an aircraft in response to an interrogator interrogator radio wave at a predetermined SSR site. Means for receiving an interrogation radio wave transmitted at a predetermined period from the rotating antenna, a period during which the interrogating means receives the interrogation radio wave during the rotation of the rotating antenna, and a period during which the response radio wave is received by the intercepting means. Means for measuring the time difference between the timing when the rotating antenna directly faces the receiving means and the timing when the rotating antenna directly faces the aircraft, means for generating a signal synchronized with the transmission timing of the interrogation radio wave, based on the synchronization signal Propagation time from the transmission of the interrogation radio wave to the reception of the response radio wave of the aircraft to the interrogation radio wave by the interception means Means for measuring the angle of rotation of the rotating antenna, and means for calculating an angle proportional to the time difference as the azimuth of the aircraft with reference to the azimuth of the response radio wave interception position from the interrogation radio wave transmission position. Means for calculating the position of the aircraft based on the azimuth of the aircraft, the response radio signal interception position, the interrogation radio wave transmission position, and the propagation time. In a preferred embodiment of the present invention, the synchronizing signal generating means generates a pulse signal synchronized with the interrogation radio wave received by the receiving means. The propagation time measuring means detects the reception timing of the response radio wave by the intercepting means within one cycle of the interrogation radio wave based on the synchronization pulse signal, and the time difference measuring means detects that the rotating antenna is the interrogation radio wave receiving means. Counting the number of synchronization pulse signals from when the interrogation radio wave is received to the rotary antenna until the response radio wave is directly received by the aircraft, and the time difference is measured based on the counted value. I do. The time difference measuring unit detects, for example, the reception timing of the interrogation radio wave at the center position within the period in which the interrogation radio wave is received by the reception unit, as the timing facing the reception unit during one rotation of the rotating antenna. Further, the aircraft azimuth calculating means calculates 360 ゜ × (the time difference) ÷ (the time when the rotating aerial antenna battles once) as the azimuth of the aircraft. [Operation] Referring to FIG. 2, the propagation time is determined by the distance l _H1 from the SSR site that transmitted the interrogation radio wave, for example, the airport PH to the aircraft S, and the distance l _H2 from the aircraft S to the reception point PR. Sum of
l corresponds to _H. That is, the aircraft S exists at one point on the ellipse EH having the SSR site PH and the receiving point PR as two focal points and having the above-mentioned distance l _H (= l _H1 + l _H2 ) as a major axis. In addition, since the rotating antenna of the interrogator transmitter at the SSR site PH has strong directivity, at the receiving point PR, the SSR site P
Only 10 to several tens of interrogation signals from H are received in the vicinity where the rotating antenna directly faces the receiving point PR every rotation. On the other hand, the aircraft S also receives only about 10 or more than 10 dozens in the vicinity when the rotating antenna faces the aircraft S every rotation, and transmits a response radio wave to the received interrogation radio wave. Here, since the rotation period of the rotating antenna at each SSR site is relatively accurate, the time difference is
Corresponds to the angle θ between the direction facing the reception point PR and the direction facing the aircraft S. Therefore, if the intersection of the ellipse EH and the straight line having the inclination θ passing through the interrogation radio wave transmission point PH is determined by the calculation unit, this is the position of the aircraft S or the like. [Effects] According to the present invention, a direction finding antenna in a conventional passive SSR and a circuit such as distribution, synthesis, and switching associated with the antenna are not required, so that the circuit configuration of the device is simplified, and the entire device is miniaturized. In addition, the cost can be reduced. Therefore, it can be mounted on an aircraft. While radars currently on board aircraft can only monitor a relatively small area ahead, substantially less than 360
監視 can be monitored, which is very effective in preventing near misses. Also, by analyzing the code of the response signal, it is possible to know the altitude and type (military, civil, company) of other aircraft. Further, the detection ability of the time difference in the device of the present invention,
It is possible to make it about ± 1 of the interrogation radio wave. In other words, if the rotation period of the rotating antenna at the SSR site is 4 seconds and the repetition frequency of the interrogation radio is 440 Hz, the direction detection accuracy is 360
{4 seconds {440Hz = approximately 0.2}, and the above JP-A-60-222782
The direction detection accuracy of the SSR device of No.5 can be dramatically improved from about 0.5 約. Furthermore, in the present invention, focusing on the fact that the rotation period of the rotating antenna of each SSR site is relatively accurate, measuring the time difference from when the rotating antenna of the predetermined SSR site directly faces its own device to when it directly faces the target. The angle θ is obtained from the time difference and the rotation period of the rotating antenna. Therefore, no retrofit is required for existing interrogators. Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 shows a configuration of a passive SSR device according to one embodiment of the present invention. The device shown in the figure has an omnidirectional antenna 11, a 1090 MHz receiver 12, a local oscillator 13, a parabolic antenna 20, 1030MHz.
It includes a receiver 30, a synchronization signal generation circuit 40, a counter 46, a data detection circuit 50, a correlation circuit 60, and a central processing unit (CPU) 70. The antenna 11, the receiver 12, and the local oscillator 13 are for receiving a response signal (1090 MHz) transmitted from a transponder mounted on the aircraft S (FIG. 2). The antenna 20 is installed toward the SSR site PH, and the rotating antenna of the transmitter of the interrogator at the SSR site PH faces the device PR every three to several seconds. During the period determined by the beam width of the SSR antenna, a burst signal composed of 10 to several interrogation signals is received. The receiver 30 transmits a burst signal (10
30 MHz) and supplies it to the synchronization signal generation circuit 40. At the SSR site PH, an interrogation signal is transmitted at a predetermined period between 200 and 450 Hz. The synchronization signal generation circuit 40 generates a pulse TRG synchronized with the inquiry signal transmission timing with high accuracy. Although the details of the circuit 40 are not shown, for example, similar to that described in Japanese Patent Application Laid-Open No. 60-222782, the reference that the interrogator transmitter of the SSR site PH has for generating the interrogation signal in the above-described predetermined cycle is used. A voltage-controlled crystal oscillator having a natural frequency equivalent to that of a clock oscillator, and ten to several tens of questions that are received and output from the receiver 30 in the vicinity of the rotating antenna of the interrogator transmitter when they face each other. A synchronous circuit that synchronizes the voltage-controlled crystal oscillator including its phase by a signal burst signal can be used. Further, the synchronization signal generation circuit 40 determines the mode MODE of the inquiry signal and sends it to the CPU 70. Further, at the reception timing of the interrogator signal of the center position of the burst signal supplied from the receiver 30, a facing signal pulse CSG indicating that the direction of the rotating antenna of the interrogator transmitter at the SSR site PH is directly facing the antenna 20. And sends it to the counter 46. The counter 46 measures the elapsed time after the occurrence of the directly-facing signal CSG.
The synchronization signal TRG sent from 40 is counted. Counter 46
Is output to the CPU 70 as angle data ANG. The data detection circuit 50 determines the reception timing of the response signal based on the synchronization pulse TRG from the output signal of the receiver 12, that is, the distance l _H (= l _H1 + l) from the SSR site PH to the device PS via the aircraft S. _H2 ) is detected, and the output signal is detected to extract the code CODE included in the response signal. Generally, each aircraft S receives a query radio wave from each of the plurality of SSR sites and transmits a response radio wave to each of them. Various noise radio waves other than the SSR response radio waves are also input to the antenna 11. The correlation circuit 60 discriminates a response signal transmitted to the interrogation radio wave of the specific SSR site PH from among the response radio waves to each of the plurality of SSR sites received by the antenna 11 and various noise radio waves. The noise radio wave is aperiodic, and the interrogation radio wave transmitted from the SSR site is periodic, but the transmission timing and the repetition period are different for each SSR site. Furthermore, the intermittent transmission cycle of the interrogation radio wave is at most 5 ms, and the movement amount of the aircraft S during this period is about 1000 km / h.
1.4m. Therefore, the propagation time of response radio waves to several consecutive interrogation radio waves transmitted from the same SSR site, that is, the distance l _H is substantially constant. On the other hand, other SS
The response radio wave and the noise radio wave transmitted to the R site are continuously received at each of a plurality of continuous interrogation radio waves (synchronous signal TRG) of a predetermined SSR site (propagation time or distance l _H ). Is not constant. The correlation circuit 60 discriminates a response signal in which the propagation time (distance) data l _H is substantially constant for several consecutive synchronization pulses TRG as a response signal to the interrogation signal sent from the SSR site PH, extracts a reception timing (distance) data l _H and code data cODE corresponding to the response signal discrimination among the data inputted from 50 is sent to the CPU 70. The CPU 70 is configured by a microprocessor or the like, and executes arithmetic processing according to various data supplied from the synchronization signal generation circuit 40, the counter 46, the correlation circuit 60, and the keyboard 71. For example, as described above, the response signal to the SSR site PH is received by only 10 to 10 or more in the vicinity where the rotating antenna of the SSR site PH faces the aircraft S as described above.
0, the received timing data l _H and code data C
ODE input timing and count value A of counter 46 at that time
The rotating antenna than NG calculates the azimuth θ when directly facing the aircraft S, further, aircraft S on the basis of the position data of the direction data θ and the timing data l _H and SSR sites PH and apparatus PS Calculate the position. Further, based on the mode data MODE and the code data CODE, the altitude information (mode C) and the status response (mode A) of the aircraft S are detected, and the position information of the aircraft within a predetermined time, that is, the wake is stored. Further, a display output signal is created based on the input, calculated and detected data, and sent to the display 72. The display 72 includes a CRT, a video RAM, a map signal ROM, and the like. Based on a display output signal from the CPU 70 and a map signal from the map signal ROM, a map, an aircraft position, a flight number, and the like within a detection range of the apparatus are provided. Display aircraft information. [Modifications of Embodiments] The present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented. For example, as described above, the interrogation signal includes a mode A for inquiring about the status of the aircraft and a mode C for inquiring about the altitude of the aircraft.
Each of H, PN, and PY is set in advance such as... AAA or. Accordingly, by using not only the reception timing data of the response signal in the correlation circuit or the CPU but also the arrangement of the decoded data of the received response signal as the determination material, it is possible to more reliably discriminate the predetermined SSR site. . Further, even when there are a plurality of aircraft within the detection range of the present apparatus, it is possible to more reliably identify the aircraft that has transmitted each response radio wave based on the decoded data of the response signal. Further, the apparatus of the present invention can detect the position of a flying object other than an aircraft or a traveling object on the ground as long as the object is equipped with a transponder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the overall configuration of a passive SSR device according to one embodiment of the present invention, and FIG. 2 is an explanatory diagram of the operation principle of the present invention. 11: Omnidirectional antenna, 12: Response signal receiver, 20: Parabolic antenna, 30: Interrogation signal receiver, 40: Synchronization signal generation circuit, 46: Counter, 50: Data detection circuit, 60: Correlation circuit, 70: CPU.

Claims (1)

(57) [Claims] Means for intercepting a response radio wave transmitted from an SSR transponder mounted on an aircraft with respect to an interrogator interrogator interrogator radio wave at a predetermined SSR site; The timing at which the rotating antenna directly faces the receiving means and the time at which the aircraft is forwarded are determined based on the period during which the interrogation means receives the interrogation radio wave during one rotation of the antenna and the time period during which the response radio wave is received by the intercepting means. Means for measuring a time difference from the timing with respect to the signal, means for generating a signal synchronized with the transmission timing of the interrogation radio wave, and a response radio wave of the aircraft to the interrogation radio wave after the interrogation radio wave is transmitted based on the synchronization signal. Means for measuring a propagation time until the signal is received by the means; Means for calculating the angle proportional to the time difference as the azimuth of the aircraft with reference to the azimuth of the response radio signal interception position from the interrogation radio signal transmission position, and the calculated aircraft orientation, the response radio signal interception position, and the interrogation radio signal transmission A passive SSR apparatus comprising: means for calculating a position of the aircraft based on the position and the propagation time. 2. 2. The passive SSR device according to claim 1, wherein said synchronization signal generating means generates a pulse signal synchronized with the interrogation radio wave received by said interrogation radio wave receiving means. 3. 2. The transmission time measuring unit according to claim 2, wherein the reception time of the response radio wave by the intercepting unit is measured based on the synchronization pulse signal within one cycle of the interrogation radio wave.
The passive SSR device described in the item. 4. The time difference measuring unit is configured to control the number of the synchronization pulse signals from when the interrogating radio wave is received by the rotating antenna directly facing the interrogating radio wave receiving unit to when the response radio wave is received by the rotating antenna directly facing the aircraft. And counting the time difference based on the counted value.
Or the passive type SSR device according to item 3. 5. 2. The method according to claim 1, wherein the time difference measuring unit detects a reception timing of the interrogation radio wave at a center position within a period in which the interrogation radio wave is received by the reception unit as a timing directly facing the reception unit during one rotation of the rotating antenna. 4th
The passive type SSR device according to the paragraph. 6. The passive type according to any one of claims 1 to 5, wherein the aircraft azimuth calculating means calculates 360 ° x (the time difference) ÷ (time during which the rotary antenna makes one rotation) as the azimuth of the aircraft. SSR equipment.