JP5606231B2 - Receiver - Google Patents

Description

  Embodiments described herein relate generally to a receiving apparatus that receives a signal transmitted from a transponder mounted on an aircraft.

  Mode S secondary monitoring radar (SSR mode S) sends questions to transponders mounted on aircraft and receives various information in response to the sent questions as a response to information related to monitoring by air traffic control. It is a device to acquire. In addition, multilateration and broadcast-type automatic dependent monitoring (ADS-B) is a device that operates by receiving a response mainly transmitted from an aircraft transponder.

  As a factor that degrades response detection performance in such a device that receives a response transmitted from an aircraft transponder, the response pulse width is narrowed. In the response, the preamble and the subsequent data block are composed of a plurality of pulses. Depending on the performance of the transponder and the reception environment, the pulse width of this pulse may be narrowed. When the pulse width is narrow in this way, the response is difficult to analyze normally, and the reliability of the analyzed response is lowered.

  If the reliability of the analyzed response is reduced, the target cannot be acquired in the case of the mode S secondary monitoring radar, and necessary information cannot be obtained in the case of multilateration or ADS-B. Monitoring performance will be degraded.

JP 2010-133781 A

Michael C. Stevens “Secondary Surveillance Radar” 1988, ISBN 0-89006-292-7

  Therefore, this embodiment provides a receiving apparatus that can analyze a reliable response even when a response with a narrow pulse width is received.

  The receiving apparatus according to the embodiment is a receiving apparatus that receives and analyzes a signal including a preamble formed by a plurality of pulses of a predetermined format and a data block formed by a plurality of pulses following the preamble. The receiving apparatus includes a correlation processing unit, a pulse width counter unit, and a data analysis processing unit. The correlation processing unit obtains a correlation between the received signal and a predetermined format, and detects a preamble from the received signal. The pulse width counter unit obtains the pulse width of each pulse of the detected preamble. When the preamble is detected, the data analysis processing unit analyzes the data block following the preamble detected from the received signal based on the average value of each pulse width of the preamble, and receives the average value of each pulse width as a reference. Determine the reliability of the signal.

It is a functional block diagram explaining the structure of the mode S secondary monitoring radar using the receiver which concerns on embodiment. It is an example of the signal handled with the receiver of FIG. It is a figure explaining the analysis in the analysis process part of FIG.

  A receiving apparatus (receiver) according to an embodiment will be described below with reference to the drawings. This receiving apparatus is an apparatus that analyzes a response transmitted from a transponder mounted on an aircraft in order to use it for grasping the flight status of the aircraft. In FIG. 1, the receiver 12 is described as being provided with a mode S secondary monitoring radar 1 that transmits and receives signals to and from the transponder 20 mounted on the aircraft 2.

  As shown in FIG. 1, the mode S secondary monitoring radar 1 is installed in a ground station. The mode S secondary monitoring radar 1 receives and processes a response transmitted from a transponder 20 provided in the aircraft 2, and receives an antenna 10, a receiver 12 that analyzes a signal received via the antenna 10, and a reception A mode S response processing unit 13 for processing a mode S response among signals analyzed by the machine 12, an ATCRBS response processing unit 14 for processing an ATCRBS response among signals analyzed by the receiver 12, a mode S response processing unit 13, and A monitoring processing unit 15 that generates data for aircraft monitoring using the processing result of the ATCRBS response processing unit 14, a channel management unit 16 that manages the transmission timing of questions, and a transmission control unit 17 that controls transmission of questions. And a transmitter 18 that transmits a question via the antenna 10 and a switch 11 that switches between transmission and reception of a signal.

  When receiving a signal, the receiver 12 is a device that detects and analyzes a signal (response) including a preamble of a predetermined format including a plurality of pulses and a data block following the preamble from the received signal. As shown in FIG. 1, the receiver 12 analyzes a received signal when a preamble is detected, a correlation processing unit 121 that detects a preamble, a pulse width counter unit 122 that obtains a pulse width that forms the preamble, and a preamble. , An analysis processing unit 123 that determines the reliability of the received signal, and an output unit 124 that outputs a reliable received signal among the analyzed received signals.

  As shown in FIG. 2, the signal analyzed by the receiver 12 is composed of an 8 μs preamble and a 56 μs or 112 μs data block, and the preamble is composed of four pulses. The interval between the first pulse and the second pulse constituting the preamble is 1 μs, the interval between the first pulse and the third pulse is 3.5 μs, and the interval between the first pulse and the fourth pulse is 4.5 μs. It is prescribed. The data block starts at a position 8 μs from the first pulse of the preamble. Here, the pulse width of each pulse constituting the preamble and the data block is set on the premise of 500 ns, but may be wider or narrower than 500 ns depending on the performance of the transponder and the reception environment.

  Although not shown in the figure, the correlation processing unit 121 receives the received signal that has been converted to digital by the A / D converter and binarized by the binarization means. The correlation processing unit 12 obtains the correlation between the input signal and a format composed of four pulses at predetermined intervals as shown in FIG. 2, detects the preamble of the received signal, and outputs the preamble detection result. The preamble detection result is input to the pulse width counter unit 122, the analysis processing unit 123, and the output unit 124.

  When the detection result of the preamble detected from the correlation processing unit 121 is input, the pulse width counter unit 122 counts the pulse widths a1 to a4 of each of the four pulses forming the preamble included in the binarized reception signal. . The pulse widths a1 to a4 of each pulse counted by the pulse width counter unit 122 are input to the analysis processing unit 123.

  FIG. 2 shows an example in which levels representing the respective pulse widths a1 to a4 are output. 20 for the first pulse width a1, 19 for the second pulse width a2, and 20 for the third pulse width a3. In the example, 20 is output for the pulse width a4 of the fourth pulse. For the preamble count, a conventionally used method can be used, and for example, a method as described in JP 2010-133781 A can be used.

  The analysis processing unit 123 inputs the detection result from which the preamble is detected from the correlation processing unit 121, and inputs the pulse width of each pulse of the preamble from the pulse width counter unit 122, and analyzes the binarized reception signal. The signal analyzed by the receiver 12 is a Manchester code, and the position of 8 μs from the first pulse of the preamble is the first data bit of the data block. Therefore, the analysis processing unit 123 outputs each data bit of the data block from the position of 8 μs to the position of 56 μs or 112 μs from the first pulse of the preamble. The analysis processing unit 123 obtains and outputs a reliability bit in addition to the data bit. The data bits and the reliability bits are input to the output unit 124.

  The signal of interest here is a Manchester code of 1 μs per bit, and is a signal in which the first half and the second half in one bit always have opposite levels. That is, in the case of normal data, data transition always occurs at the center of the bit, and therefore the analysis processing unit 123 analyzes by providing a detection window at the center of the bit.

  In the present embodiment, description will be made assuming that the logic is “0” when the bit is “01” and the logic is “1” when the bit is “10”. Specifically, for the data bits, the analysis processing unit 123 sets the logic “0” when the analysis unit 123 c detects the rising edge within the detection window for each bit, and sets the logic “1” when the falling edge is detected. Further, the analysis processing unit 123 sets the reliability to “Yes” when the determination unit 123d detects the rising or falling edge within the detection window for each bit, and does not detect the rising or falling edge. Sometimes reliability is “no”. That is, when there is a rising or falling edge within the detection window, it can be determined that the signal is not an unnecessary signal but a usable bit.

  At this time, the analysis processing unit 123 obtains an average value of the pulse width of each pulse of the preamble by the calculation unit 123a, and sets the setting of the detection window used for pulse detection by the setting unit 123b. Therefore, the analysis unit 123c analyzes the data bit using the detection window set by the setting unit 123b, and the determination unit 123d determines the reliability using the detection window set by the setting unit 123b.

  For example, as shown in FIG. 3A, when the pulse width is 500 ns (pulse width level 20) and there is a fall in the detection window, the data bit is “1” and the reliability bit is “present”. Is analyzed. However, as shown in FIG. 3B, when the pulse width is narrower or wider than the range detectable by the detection window, such as 400 ns (pulse width level 16), the rising or falling edge falls within the detection window. Since no data exists, the data bit cannot be detected and the reliability bid is analyzed as “none”. Therefore, even if a signal to be used is received, it cannot be used when the pulse width is narrow or wide. On the other hand, even if the pulse width is 400 ns, the detection window having a wide range that can be detected by the setting means 123b is shown in FIG. When is set, there are rising and falling edges in the detection window. Therefore, in the case shown in FIG. 3C, by adjusting the detection window, the analysis unit 123c analyzes the data bit as “1”, and the determination unit 123d determines that the reliability bit is “present”. Can do.

  When the output unit 124 receives the data bits and the reliability bits from the analysis processing unit 123 for the received signal, the output unit 124 outputs the received signal to the subsequent stage with respect to a signal that has all the reliability bits “present” and is reliable.

  In this way, the receiver 12 sets a pulse detection window according to the pulse width and analyzes the data bit and the reliability bit, so that a reliable response can be obtained even when a response with a narrow pulse width is received. Can be analyzed.

  In FIG. 1, the receiver 12 is described as being provided in the mode S secondary monitoring radar 1, but the receiver 12 is a multi-lateration system receiving device or ADS-B that receives a similar signal. It can also be used as a receiving device.

  As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. Further, the present invention naturally includes various embodiments not described herein.

DESCRIPTION OF SYMBOLS 1 ... Secondary monitoring radar 10 ... Antenna 11 ... Switching machine 12 ... Receiver 121 ... Correlation processing part 122 ... Pulse width counter part 123 ... Analysis processing part 123a ... Calculation means 123b ... Setting means 123c ... Analysis means 123d ... Determination means 124 ... Output unit 13 ... Mode S response processing unit 14 ... ATCRBS response processing unit 15 ... Monitoring processing unit 16 ... Channel management unit 17 ... Transmission control unit 18 ... Transmitter 2 ... Aircraft 20 ... Transponder

Claims (2)

A mode S secondary monitoring radar is provided for receiving and analyzing a signal comprising a preamble formed by a plurality of pulses of a predetermined format transmitted from an aircraft and a data block formed by a plurality of pulses following the preamble. A receiving device,
A correlation processing unit for obtaining a correlation between the received signal and the predetermined format and detecting a preamble from the received signal;
A pulse width counter for obtaining the pulse width of each pulse of the detected preamble;
An arithmetic means for obtaining an average value of each pulse width of the preamble obtained by the pulse width counter unit, a setting means for setting a detection window used for pulse detection according to the average value obtained by the arithmetic means, Analyzing means for detecting the rising or falling edge of the pulse in the detection window set by the setting means and analyzing the data block of the received signal; presence or absence of rising or falling of the pulse in the detection window set by the setting means A data analysis processing unit having a determination unit that detects the reliability of the received signal by detecting
A receiving apparatus comprising: Claims wherein the input from the data analyzing unit and the analysis result of the data block and reliability determination results, characterized by further comprising an output unit for outputting as a reception signal only valid data including reliable data blocks Item 4. The receiving device according to Item 1 .

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