JP6271475B2 - Reflective radar receiver - Google Patents

Description

The present invention relates to a reflection-type radar receiver for detecting the position of the aircraft.

  Airfield air traffic control stations are usually equipped with a primary monitoring radar and a secondary monitoring radar. The primary monitoring radar detects the position of the aircraft based on the time from when the detection wave is output until the detection wave is reflected by the aircraft and returns. On the other hand, the secondary monitoring radar detects the position of the aircraft based on the time from the output of the A interrogation wave and the C interrogation wave to the arrival of the response wave returned by the aircraft transponder.

  In order to cope with the increase in aircraft in recent years, the secondary monitoring radar transmits a mode S interrogation wave having a larger amount of information than the A interrogation wave and the C interrogation wave, and the aircraft transponder is uniquely set accordingly. A response wave containing information is returned, and an aircraft position is detected based on the response wave (see, for example, Patent Document 1).

  In addition, for example, in order to make safer flights of the Self-Defense Forces, media organizations and doctor helicopters that are urgently dispatched immediately after the occurrence of a major disaster such as an earthquake, questions on the secondary monitoring radar system of the Air Traffic Control Station A technique for acquiring position information of an aircraft using a radar receiver that is not related to an air traffic control station has also been developed (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 08-179039 (paragraphs [0001], [0002])

JP 2014-231995 A (paragraph [0004])

  By the way, if the position information of an aircraft is acquired by a radar receiver unrelated to the above-described air traffic control station, it is not possible to acquire the position of an aircraft not equipped with a transponder or an aircraft in which the transponder is broken. In addition, there is a request at the Air Traffic Control Bureau that only the secondary monitoring radar is used to monitor the aircraft and the primary monitoring radar is abolished to reduce the maintenance cost of the monitoring radar. In this case as well, an aircraft not equipped with a transponder There arises a problem that it becomes impossible to perform monitoring.

The present invention has been made in view of the above circumstances, without also not utilized transponders primary surveillance radar, and an object thereof is to provide a reflection-type radar receiver capable of detecting the position of the aircraft.

In order to achieve the above object, the invention of claim 1 is characterized in that a receiving circuit that takes in a radio wave having the same frequency as the interrogation wave of mode S of the secondary monitoring radar system as an inspection target wave, and the inspection target wave. A direct wave detection unit that detects a direct reception equivalent unit that corresponds to the interrogation wave received without reflection, and an autocorrelation value of a reference wave that is a part of the interrogation wave among the inspection target waves Based on the reflected wave detection unit for detecting the primary reflection reception equivalent part corresponding to the primary reflection wave of the interrogation wave, between the direct reception equivalent part and the primary reflection reception equivalent part of the inspection target wave Information included in the reference wave by demodulating the reference wave included in the direct reception equivalent part of the inspection target wave and a position calculating part that calculates the position of the reflector that reflects the interrogation wave based on the elapsed time And a demodulator for extracting An ideal reference wave generation unit that generates digital data of the carrier pattern of the reference wave obtained by modulating the information extracted by the modulation unit, and an A / D converter that converts the carrier pattern of the inspection target wave into digital data The reflected wave detection unit includes the autocorrelation of the reference wave from the digital data of the carrier pattern of the inspection target wave and the digital data of the carrier pattern of the reference wave generated by the ideal reference wave generation unit. It is a reflection type radar receiver that calculates a value .

  According to a second aspect of the present invention, the receiving circuit includes a first receiving circuit and a second receiving circuit, which are separately installed with antennas connected thereto and are separated from each other, and take in the inspection object wave, and the direct wave detection The unit detects the direct reception equivalent unit from the inspection target wave captured by the first reception circuit, while the reflected wave detection unit detects the primary from the inspection target wave captured by the second reception circuit. The reflection type radar receiver according to claim 1, wherein a reflection reception equivalent part is detected.

The invention according to claim 3 is the reflection type radar receiver according to claim 1 or 2 , wherein the reference wave includes a portion unique to each interrogation wave and is entirely longer than the preamble of the interrogation wave. .

In the reflective type radar receiver of the present invention, the reflector which reflects the interrogating wave based on the time from the output of the interrogation wave from the antenna of the secondary surveillance radar system to the primary reflected wave of the interrogating wave is received The position of is detected. That is, according to the reflection type radar receiver of the present invention, the position of the aircraft can be detected without using the primary monitoring radar or the transponder. Here, even if the primary reflected wave of the secondary monitoring radar system is simply received, the output of the radar wave of the secondary monitoring radar system is smaller than the output of the radar wave of the primary monitoring radar system. The reflected wave and the noise cannot be distinguished. On the other hand, in the reflection type radar receiver of the present invention, the primary reflected wave is detected based on the autocorrelation value of the reference wave that is a part of the interrogation wave. Even a primary reflected wave of a wave can be determined as noise. In addition, since the interrogation wave of mode S having a longer and more complicated wave shape than the A interrogation wave and the C interrogation wave is used, the primary reflected wave and the noise are easily discriminated based on the autocorrelation value. be able to. Thus, according to the reflection type radar receiver of the present invention, the position of the aircraft can be detected without using the primary monitoring radar or the transponder as described above.

As a configuration for calculating the autocorrelation value, the autocorrelation value may be calculated between the signal waves obtained by demodulating the reference wave and the inspection target wave. It is difficult to detect a primary reflected wave. On the other hand, in the reflection type radar receiver of the present invention, the autocorrelation value is calculated between the carrier patterns of the reference wave and the inspection target wave, so that the influence of noise can be suppressed and accurate primary reflected wave can be detected. Become.

In the reflection type radar receiver of the present invention, a part or all of the direct reception equivalent part corresponding to the interrogation wave received without reflection among the inspection object waves is taken in as a reference wave and demodulated, and the reference wave Extract information contained in. Here, the direct reception equivalent part corresponding to the interrogation wave received without reflection among the waves to be inspected is high in intensity, so even if it contains noise, it is not easily affected, and information can be obtained with high accuracy. It can be taken out. Then, the information is modulated to generate reference wave digital data. As a result, the autocorrelation value can be calculated using a carrier pattern of a reference wave that is not substantially affected by noise, and an accurate primary reflected wave can be detected.

In the reflection type radar receiver according to the third aspect , since the reference wave is longer than the preamble of the interrogation wave, the reliability of the autocorrelation value becomes high, and the primary reflected wave can be detected more accurately.

Schematic diagram of secondary monitoring radar according to the first embodiment of the present invention. Reflective radar receiver circuit diagram Block diagram of a reflective radar receiver Graph showing changes in autocorrelation values Waveform diagram of inspection target wave Waveform diagram of ideal preamble Graph showing phase difference between preambles and change of autocorrelation value Radar monitor display screen Block diagram of a reflective radar receiver according to the second embodiment Waveform diagram of carrier pattern of S interrogation wave Graph showing the phase difference between S interrogation waves and the change in autocorrelation value Circuit diagram of reflective radar receiver of third embodiment Block diagram of the reflective radar receiver Circuit diagram of reflective radar receiver of fourth embodiment Block diagram of the reflective radar receiver Circuit diagram of reflection type radar receiver of fifth embodiment

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The secondary monitoring radar system 11 corresponding to the mode S provided in the air traffic control station of the airfield has an antenna 11A (see FIG. 1) that rotates at a period of 4 seconds per rotation, for example, and has a carrier wave of 1030 [MHz] according to regulations. QPSK (Quad-Phase-Shift Keying) modulated mode S interrogation wave (hereinafter referred to as “S interrogation wave”) is output through the antenna 11A at a predetermined interval (for example, approximately 5 [ms]). A general aircraft 90 (airplane, helicopter, etc.) is equipped with a transponder 91 that responds to the S interrogation wave. Upon receipt of the S interrogation wave, the transponder 91 outputs a mode S response wave at a frequency of 1090 [MHz] after a predetermined time has elapsed. Then, this is received by the secondary monitoring radar system 11 through the antenna 11A, and the position of the aircraft 90 is calculated and displayed on a monitor (not shown) based on the time from when the S interrogation wave is output until the response wave is received. .

  By the way, some aircraft 90 are not equipped with the mode S transponder 91. Even if the transponder 91 is mounted, there may be a failure. In contrast, an air traffic control station is usually equipped with a primary monitoring radar. The primary monitoring radar outputs a detection wave with a larger output than the secondary monitoring radar and receives the reflected wave of the detection wave in the aircraft 90 to detect the position of the aircraft 90. The air traffic control station of this embodiment Is provided with a reflection type radar receiver 20 according to the present invention that detects the position of the aircraft 90 using the reflected wave of the S interrogation wave of the secondary monitoring radar system 11 instead of the primary monitoring radar. .

  FIG. 2 shows a basic configuration of the reflective radar receiver 20. The reflection type radar receiver 20 takes in a radio wave having the same frequency as the S interrogation wave of the secondary monitoring radar system 11, that is, an infinite wave of 1030 [MHz], as an inspection target wave. Specifically, in the receiving circuit 20A provided in the reflective radar receiver 20, a radio wave is received through the antenna 21, amplified by the amplifier 22, and then generated, for example, by a local wave of 1000 [MHz] generated by the transmitter 23. Mixing is performed by the mixer 24 and converted to an intermediate frequency. Then, the received wave of the intermediate frequency is passed through the band-pass filter 25 through which only the signal of [30 MHz] can pass, thereby extracting and capturing the radio wave of 1030 [MHz] as the inspection target wave of 30 [MHz]. Then, the reflection type radar receiver 20 detects a portion corresponding to the primary reflected wave of the S interrogation wave from the inspection target wave based on the autocorrelation value of the S interrogation wave.

  In order to calculate the autocorrelation value, the A / D converter 26 provided in the reflective radar receiver 20 performs A / D conversion on the inspection target wave at a predetermined sampling period (for example, several tens [ns]). Then, reception wave height data for specifying the wave height of the inspection target wave for each sampling period is generated and transferred to the CPU 29 of the reflection radar receiver 20. The CPU 29 executes a predetermined signal processing program stored in the ROM 28 and sequentially buffers the received wave height data received from the A / D converter 26 in the flash memory 27.

  The ROM 28 functions as the reference wave storage unit 29F according to the present invention, and stores, for example, reference wave height data obtained by A / D converting the ideal waveform of the preamble of the S interrogation wave at the above-described sampling period. . The number of data of the reference wave height data is a constant reference number obtained by [preamble length] / [sampling period].

  The CPU 29 executes the above-described signal processing program, whereby the autocorrelation value calculation unit 29A, the first detection unit 29B (corresponding to the “direct wave detection unit” of the present invention) shown in the block diagram of FIG. 2 functions as a detection unit 29C (corresponding to the “reflected wave detection unit” of the present invention), a position calculation unit 29D, and the like. The autocorrelation value calculation unit 29A calculates an autocorrelation value as described below when a predetermined reference number of received wave height data is buffered. That is, the fixed reference number is n, and the received wave height data is x (1), x (2), x (3),..., X (n) in the order of generation, and the reference wave height data from the head side. Assuming y (1), y (2), y (3),..., Y (n) in order, the CPU 29 executing the signal processing program calculates the autocorrelation value Φ (m ) Is calculated.

  The autocorrelation value calculation unit 29A generates a reception wave height data group to be calculated, which is used for calculating the autocorrelation value Φ (m) every time one new reception wave height data is generated. The oldest received wave height data x (1) is removed from several n received wave height data x (1), x (2),..., X (n), and other received wave height data x (2), ( 3),..., X (n) are moved up to received wave height data x (1), x (2),..., X (n-1), and newly generated received wave height data is received. This is added to the reception wave height data group to be calculated as wave height data x (n). Then, the autocorrelation value Φ (2) is calculated from the above equation (1). In this way, the autocorrelation value calculation unit 29A sequentially calculates the autocorrelation values Φ (m), (m = 1, 2, 3,...) For each sampling period.

  Here, FIG. 4 shows an example of a graph in which the above-described autocorrelation values Φ (m) are arranged with the horizontal axis as time and the vertical axis as size. Further, FIG. 5 shows a wave to be inspected which is source data of this graph. Further, FIG. 6 shows an ideal preamble waveform used for calculating the autocorrelation value described above. FIG. 7 also shows a graph in which ideal preambles are shifted in phase by a predetermined amount to obtain an autocorrelation value, the horizontal axis indicates the phase shift amount, and the vertical axis indicates the autocorrelation value. .

  As shown in FIG. 7, when an autocorrelation value between ideal preambles is obtained, the autocorrelation value may not become zero even if the phases of both preambles are shifted from each other. Compared to other cases, the autocorrelation value becomes extremely large. From this, it can be seen that the preamble of the S interrogation wave can be used to determine whether or not they have the same waveform based on the autocorrelation value.

  In view of this, in the autocorrelation value graph shown in FIG. 4, a peak (hereinafter referred to as “first peak A”) in which the autocorrelation value is remarkably larger than the others as indicated by a symbol A. ) Can be estimated as the reflection type radar receiver 20 receiving the S interrogation wave without reflection (hereinafter referred to as “direct reception equivalent part”). Therefore, the first detection unit 29B detects, for example, a portion where the autocorrelation value is equal to or greater than a predetermined first reference value K1, as shown in FIG. The extinction time (the time at the right end of the first peak A in the details of FIG. 4) is stored as the origin time P1.

  In the graph of FIG. 4, the autocorrelation value is smaller than the first peak A as indicated by symbols B and C, but is relatively large in the entire graph (hereinafter referred to as “second peak B”). , C ”). Such second peaks B and C are obtained by the reflection type radar receiver 20 receiving the S interrogation wave through the primary reflection (one reflection) (hereinafter referred to as “primary reflection reception equivalent part”). Can be estimated. In addition, there are a plurality of points where the autocorrelation value increases instantaneously as much as the second peaks B and C, but such points are estimated to be noise. Therefore, the second detection unit 29C includes, for example, a portion where the autocorrelation value is equal to or greater than a predetermined second reference value K2 and less than the first reference value K1 in the inspection target wave, including the noise. And the generation time (sampling time) of these primary reflection reception equivalent parts is stored as the reflection time. In FIG. 4, the width when the reference line meaning the second reference value K2 crosses the protrusion corresponding to the noise is slight, but the width when the reference line that crosses the second peaks B and C is large. As can be seen from the above, a plurality of reflection times corresponding to noise are scattered, and a plurality of reflection times corresponding to the second peaks B and C are collected.

  The position calculation unit 29D calculates the position of the reflector that reflects the S interrogation wave by a known method based on the time difference between the origin time P1 and each reflection time.

  Specifically, the position calculation unit 29D determines the position of the antenna 11A of the secondary monitoring radar system 11 specified on the map, the position of the antenna 21 of the reflective radar receiver 20 specified by GPS, and the rotation of the antenna 11A. Profiling data is created by pairing the time when the S interrogation wave is output from the antenna 11A (hereinafter referred to as the transmission time) and the transmission direction (the rotational position of the antenna 11A) from the speed and the origin time P1.

  Next, the position calculation unit 29D pairs the reflection time and the transmission time before the reflection time and within a predetermined period (for example, 50 [μs]), and sets the paired reflection time and transmission time. The total propagation distance until the S interrogation wave is received from the antenna 11A of the secondary monitoring radar system 11 through the reflector to the antenna 21 of the reflective radar receiver 20 is calculated on the basis of the difference ΔT1 and the light velocity c. To do. Then, based on the total propagation distance, an ellipse whose focal point is the position of the two antennas 11A, 21 is calculated, the transmission direction of the S interrogation wave at the paired transmission time, and a general estimated value of the flight altitude The position of the reflector in the three-dimensional space is calculated, and the horizontal distance from the antenna 11A to the reflector is calculated.

  Then, as shown in FIG. 8, in the monitor 30 centered on the antenna 11A of the secondary monitoring radar system 11, the second peak B is located at a position away from the center by the horizontal distance and on the origin direction. A dot corresponding to the vertex (white point in FIG. 8) is displayed.

  In the second peaks B and C, dots corresponding to portions other than the vertices that are equal to or higher than the second reference value K2 are also displayed on the monitor 30 in the same manner as the dot display at the vertices described above. In other words, the dot group corresponding to the second peaks B and C is displayed on the monitor 30 in a collective state, as indicated by the symbol N in FIG. On the other hand, dots corresponding to noise are displayed as white dots scattered on FIG. Thereby, on the monitor 30, the dot display by noise and the dot display by a reflector can be distinguished. In addition, when the reflector is an aircraft and moves, the dot group moves on the monitor 30 with the passage of time. For example, when the reflector is a building or a mountain range, the position is constant even after the passage of time. Will remain in the display. Thereby, on the monitor 30, the building etc. which reflect S interrogation wave, and an aircraft can be distinguished.

  In FIG. 8, the dot group indicated by the symbol L is a building group near the airport, the dot group indicated by the symbol M is a mountain range, and the dot group indicated by the symbol N is an aircraft. is there.

  As described above, the reflection type radar receiver 20 of the present embodiment detects the position of the reflector using the reflected wave of the S interrogation wave of the secondary monitoring radar system 11 without using the primary monitoring radar or the transponder. can do. Here, even if the primary reflected wave of the interrogation wave output from the secondary monitoring radar system 11 is simply received, the output of the radar wave of the secondary monitoring radar system 11 is compared with the output of the radar wave of the primary monitoring radar system. Therefore, the primary reflected wave and the noise cannot be distinguished. On the other hand, in the reflection type radar receiver 20 of the present embodiment, the primary reflected wave is detected based on the autocorrelation value of the reference wave that is a part of the interrogation wave. Even the primary reflected wave of 11 interrogative waves can be determined as noise. In addition, since the interrogation wave of mode S having a longer and more complicated wave shape than the A interrogation wave and the C interrogation wave is used, the primary reflected wave and the noise can be easily discriminated based on the autocorrelation value. Can do. Thus, according to the reflection type radar receiver 20 of the present embodiment, as described above, the position of the aircraft can be detected without using the primary monitoring radar and the transponder, and the primary monitoring of the air traffic control station is performed. The maintenance cost of surveillance radar can be reduced by eliminating the radar.

  By the way, as a configuration for calculating the autocorrelation value, the autocorrelation value may be calculated between signal waves obtained by demodulating the reference wave and the inspection target wave, but in that case, noise included in the inspection target wave is also demodulated. Therefore, accurate detection of the primary reflected wave can be difficult. On the other hand, in the reflection type radar receiver 20 of this embodiment, since the autocorrelation value is calculated between the carrier patterns of the reference wave and the inspection target wave, the influence of noise can be suppressed and accurate detection of the primary reflected wave can be performed. It becomes possible. In addition, since the digital data of the carrier pattern of the reference wave is stored in the ROM 28 and the autocorrelation value is calculated using the carrier pattern of the reference wave that is not affected by the noise stored in the ROM 28, an accurate primary The reflected wave can be detected.

[Second Embodiment]
This embodiment is shown in FIG. 9 to FIG. 11, and the reflection type radar receiver 20 of the first embodiment previously stores a reference wave height data group related to an ideal preamble not including noise in a reference wave storage unit. The reflection radar receiver 20V according to the present embodiment takes in the entire portion corresponding to the direct reception of the inspection target wave as a reference wave, generates a reference wave height data group one by one, and stores the reference wave storage unit. The difference is that it is stored in 29F.

  Specifically, the CPU 29 provided in the reflective radar receiver 20V functions as the demodulator 29G, the ideal reference wave generator 29H, etc. shown in FIG. 9 by executing a signal processing program stored in the ROM 28. . The demodulating unit 29G identifies a part of the inspection target wave whose wave height is equal to or higher than a predetermined reference level as a direct reception equivalent part, and demodulates the entire direct reception equivalent part as a reference wave according to the present invention. , Information included in the S interrogation wave (binary information consisting of “0” and “1”) is extracted. Then, the ideal reference wave generation unit 29H obtains a reference wave carrier pattern obtained by modulating the information described above, generates a plurality of reference wave height data related to the reference wave carrier pattern, and generates a reference wave storage unit 29F. To remember. Note that the number of reference wave height data is a fixed reference number obtained by [total length of direct reception equivalent part] / [sampling period]. As in the first embodiment, the autocorrelation value calculation unit 29A self-corresponds to the self-correlation value calculation unit 29A from the plurality of received wave height data constituting the carrier pattern of the inspection target wave and the plurality of reference wave height data constituting the reference wave carrier pattern. The correlation value is calculated, and the CPU 29D calculates the position of the reflector and displays it on the monitor 30.

  By the way, since the direct reception equivalent part of the inspection target wave has high reception intensity, even if it includes noise, it is not easily affected, and information can be demodulated with high accuracy. Since the reference wave height data of the reference wave carrier pattern obtained by modulating the information is generated, the autocorrelation value can be calculated using the reference wave carrier pattern that is substantially unaffected by noise, An accurate primary reflected wave can be detected. In this embodiment, since the entire direct reception equivalent part of the inspection target wave is used as the reference wave, the autocorrelation value is more reliable than when a part of the direct reception equivalent part (for example, preamble) is used as the reference wave. The degree becomes higher, and the primary reflected wave can be detected more accurately.

  FIG. 10 shows the carrier pattern of the entire S interrogation wave (that is, the entire direct reception equivalent part of the inspection target wave). FIG. 11 shows the result of obtaining the autocorrelation value of the entire S interrogation wave for the entire S interrogation wave, as in the case of obtaining the autocorrelation value of the preamble itself with the preamble shown in FIG. . Even if FIG. 7 and FIG. 11 are compared, when the entire direct reception equivalent part of the inspection target wave is used as the reference wave, a part of the direct reception equivalent part (for example, a preamble) is used as the reference wave. It can be seen that the reliability of the autocorrelation value is higher than that of the case.

[Third Embodiment]
This embodiment is shown in FIGS. 12 and 13. The reflection type radar receiver 20W of the present embodiment includes a first receiving device 20S disposed in the vicinity of an airfield (for example, within a radius of 5 km from the airfield) and a remote place (for example, from an airfield) And a second receiving device 20T disposed at a position 10 to 100 [km] away. Further, the first and second receivers 20S and 20T have an electrical configuration in which a GPS module 31 and a WiMAX terminal 32 are added to the reflection radar receiver 20 of the first embodiment as shown in FIG. And connected to each other through an internet line. The receiving circuit 20A of the first receiving device 20S corresponds to the “first receiving circuit” according to the present invention, and the receiving circuit 20A of the second receiving device 20T corresponds to the “second receiving circuit” according to the present invention.

  The CPU 29 of the first receiving device 20S executes a signal processing program in the same manner as the reflection radar receiver 20 of the first embodiment, and as shown in the upper side of FIG. It functions as the part 29B etc. and also functions as the time stamp part 29J. Then, as in the first embodiment, the first detection unit 29B detects the direct reception equivalent part, and the time stamp part 29J determines the above disappearance time of the direct reception equivalent part based on the clock function of the GPS module 31. It is specified and given to the second receiver 20T as the origin time.

  The CPU 29 of the second receiver 20T executes a signal processing program in the same manner as the reflection radar receiver 20 of the first embodiment, and as shown in the lower side of FIG. In addition to functioning as a detection unit 29C and the like, it also functions as a time stamp unit 29J and a position calculation unit 29D. Then, as in the first embodiment, the second detector 29C detects the primary reflection reception equivalent part, and the time stamp part 29J determines the generation time of the temporary reflection reception equivalent part based on the clock function of the GPS module 31. It specifies and gives it to position calculating part 29D as a reflection time.

  The position calculation unit 29D includes the given reflection time, the origin time acquired from the first receiving device 20S, the positions of the first and second receiving devices 20S and 20T, and the antenna 11A of the secondary monitoring radar system 11. From the position, the position of the reflector that reflects the S interrogation wave is calculated and displayed on the monitor 30 by a known method substantially the same as in the first embodiment.

[Fourth Embodiment]
This embodiment is shown in FIGS. 14 and 15. As shown in FIG. 14, the reflective radar receiver 20X of this embodiment has an electrical configuration in which, for example, a WiMAX terminal 32 is added to the reflective radar receiver 20 of the first embodiment. It is connected to the next monitoring radar system 11. Then, as shown in FIG. 15, the position calculation unit 29D of the reflective radar receiver 20X acquires the above-mentioned profiling data of the transmission time and transmission direction of the S interrogation wave from the secondary monitoring radar system 11, and the profiling data And the reflection time detected by the second detection unit 29C, the position of the reflector is calculated and displayed on the monitor 30 as in the first embodiment. This embodiment also has the same effect as the first embodiment. In the present embodiment, the position calculation unit 29D corresponds to a “transmission time acquisition unit” and a “reception time acquisition unit” in addition to the “position calculation unit” according to the present invention.

[Fifth Embodiment]
The reflective radar receiver 20Y of this embodiment is shown in FIG. 16, and is incorporated in the secondary monitoring radar system 11Y. The secondary monitoring radar system 11Y of the present embodiment has a known configuration except for the reflection type radar receiver 20Y. That is, the control circuit 11D of the secondary monitoring radar system 11Y drives the transmission circuit 11B at an interval of approximately 5 [ms] to output the S interrogation wave through the antenna 11A. In addition, the control circuit 11D generates the above-described profiling data of the transmission time and transmission direction of each S interrogation wave. Further, the control circuit 11D causes the receiving circuit 11C to receive and demodulate the signal of 1090 [MHz] through the antenna 11A, and takes in the answer signal returned from the aircraft transponder in response to the S interrogation wave. Then, the position of the aircraft is detected on the basis of the reception time of the answer signal and the transmission time and transmission direction of the S interrogation wave being profiled, and the monitor 11E displays it.

  On the other hand, the CPU 29 of the reflective radar receiver 20Y according to the present embodiment receives the profiling data from the control circuit 11D and causes the receiving circuit 20A to receive a signal of 1030 [MHz] through the antenna 11A. Then, the reflection time as the generation time of the primary reflection reception equivalent part of the received wave is obtained by the same processing as in the first embodiment, and the position of the aircraft is detected from the reflection time and profiling data and displayed on the monitor 30. To do.

  According to the configuration of the present embodiment, the primary monitoring radar of the air traffic control station can be abolished to reduce maintenance costs.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be implemented with various modifications other than those described above without departing from the scope of the invention.

11, 11Y Secondary monitoring radar system 11A Antenna 20, 20V, 20W, 20X, 20Y Reflective radar receiver 20A Receiver circuit 29A Autocorrelation value calculator 29B First detector (direct wave detector)
29C 2nd detection part (reflected wave detection part)
29D position calculation unit (transmission time acquisition means, reception time acquisition means)
29F Reference wave storage unit 29G Demodulation unit 29H Ideal reference wave generation unit 30 Monitor

Claims (3)

A receiving circuit that captures a radio wave having the same frequency as the interrogation wave of mode S of the secondary monitoring radar system as an inspection target wave;
A direct wave detection unit for detecting a direct reception equivalent part corresponding to the interrogation wave received without reflection from the inspection target wave;
Based on the autocorrelation value of the reference wave that is a part of the interrogation wave, the reflected wave detection unit that detects a primary reflection reception equivalent part corresponding to the primary reflection wave of the interrogation wave, from among the inspection target waves,
A position calculator that calculates a position of a reflector that reflects the interrogation wave based on an elapsed time between the direct reception equivalent part and the primary reflection reception equivalent part of the inspection target wave;
A demodulator that demodulates the reference wave included in the direct reception equivalent part of the inspection target wave and extracts information included in the reference wave;
An ideal reference wave generation unit that generates digital data of a carrier pattern of the reference wave obtained by modulating the information extracted by the demodulation unit;
An A / D converter that converts the carrier pattern of the inspection target wave into digital data,
The reflected wave detection unit calculates the autocorrelation value of the reference wave from the digital data of the carrier pattern of the inspection target wave and the digital data of the carrier pattern of the reference wave generated by the ideal reference wave generation unit the reflection-type radar receiver. The receiving circuit is composed of a first receiving circuit and a second receiving circuit, which are separately connected to an antenna and installed at a remote location, and which captures the inspection target wave.
The direct wave detection unit detects the direct reception equivalent unit from the inspection target wave captured by the first reception circuit,
The reflective radar receiver according to claim 1, wherein the reflected wave detection unit detects the primary reflection reception equivalent unit from the inspection target wave captured by the second reception circuit. The reflection type radar receiver according to claim 1, wherein the reference wave includes a portion unique to each interrogation wave and is entirely longer than a preamble of the interrogation wave .