JP5380179B2 - Signal receiving device - Google Patents

Description

  The present invention relates to a signal receiving apparatus that receives a signal transmitted from a mode S transponder mounted on an aircraft.

  The aircraft is monitored by a monitoring device on the ground, but there is an aircraft in which an ADS-B compatible transponder is mounted, and the ADS-B compatible transponder periodically transmits and receives an extended squitter between the aircraft.

  In general, the extended squitter is a signal used between aircrafts equipped with ADS-B compatible transponders, but there is also an apparatus that receives and uses the extended squitter transmitted from the aircraft on the ground (for example, And Japanese Patent Application No. 2009-618).

  For example, as shown in FIG. 4, the ADS-B compatible transponder 2 provided in the aircraft transmits and receives signals such as an extended squitter via the antenna 20 and receives signals transmitted from other aircraft and the like. And a signal processing unit 22 that executes generation of a signal transmitted by the transmission / reception unit 21 and analysis processing of the signal received by the transmission / reception unit 21. The extended squitter receiving apparatus 1a that receives the extended squitter on the ground includes a receiving unit 11 that receives a signal such as an extended squitter transmitted from the transponder 2 of the aircraft via the antenna 10, and a signal received by the signal processing unit 12a Is provided with a signal processing unit 12a for executing the analysis processing.

  For example, as shown in FIG. 5, the extended squitter has an 8 μs preamble that identifies the extended squitter and a 112 μs data block that is actual data of the extended squitter. The preamble is composed of a first pulse to a fourth pulse each having a pulse width of 0.5 μs, 1 μs from the rising edge of the first pulse to the rising edge of the second pulse, and from the rising edge of the first pulse to the rising edge of the third pulse. The period from the rising edge of the first pulse to the rising edge of the fourth pulse is defined as 4.5 μs.

  As shown in FIG. 6, the signal processing unit 12 a of the extended squitter receiving device 1 a uses a preamble detection unit 121 that detects the preamble of the extended squitter and a detection result of the preamble detection unit 121 to convert a data block included in the received data. And decoding processing means 122 for decoding.

  The preamble detection unit 121 receives the reception data received by the antenna 10 from the reception unit 11 and the decoding completion signal for determining that the decoding process is completed from the decoding processing unit 122. The preamble detection unit 121 detects the preamble from the received data and outputs the presence / absence of the preamble to the decoding processing unit 122 as a detection result. Here, after detecting the preamble, the preamble detection unit 121 cannot execute the preamble detection process until a decoding completion signal for notifying the end of the decoding process is input from the decoding processing unit 122.

  The decode processing unit 122 receives the reception data received by the antenna 10 from the reception unit 11 and the preamble detection result from the preamble detection unit 121. Further, when receiving the detection result with the detection of the preamble, the decoding processing means 122 detects and decodes the data block of the extended squitter from the received data. Further, when the decoding process of the data block is completed, the decoding processing unit 122 notifies the end of the decoding process of the data block and outputs a decoding completion signal permitting the restart of the preamble detection to the preamble detecting unit 121. Here, the decoding process ends when the data for 112 μs is decoded from the start of the data block. That is, as described with reference to FIG. 5, the extended squitter has a preamble of 8 μs, and the data block has 112 μs after the preamble. Therefore, the decoding processing unit 122 can determine the end of the decoding process of the data block by using the preamble and the data length (120 μs) of the data block.

  Here, the mode S transponder corresponding to ADS-B may transmit a short response having a data length different from that of the extended squitter in addition to the extended squitter. The preamble of this short response is also shown in FIG. It is a preamble similar to the extended squitter used above. Therefore, the extended squitter receiving device 1a cannot distinguish whether the received signal is an extended squitter or a short response until the data block is decoded.

  Therefore, in the extended squitter receiving apparatus 1a, even when a short response is received, as shown in FIG. 7A, when the preamble is detected by the preamble detection unit 121, the decoding processing unit 122 detects the preamble from the preamble. The decoding process of the data block of the extended squitter is executed for 120 μs. However, as shown in FIG. 7A, the signal decoded by the decoding processing means 122 at this time is a short response data block and an unnecessary signal thereafter, and the decoding processing means 122 does not need unnecessary decoding processing. Will be executed.

  Further, the extended squitter receiving apparatus 1a may receive a noise signal, and the preamble detection unit 121 may erroneously detect the noise signal as a preamble because the noise has the same pulse train as the preamble. For example, as shown in FIG. 7B, when the preamble detection unit 121 erroneously detects a noise signal as a preamble, a signal that is subsequently decoded by the decoding processing unit 122 is not a data block. This means that unnecessary decoding processing is being executed.

  On the other hand, even if the extended squitter is received during such an unnecessary decoding process, the preamble detection unit 121 is not in a detectable state (detection standby state), so the preamble of this extended squitter cannot be detected. . Therefore, as shown in FIG. 7, the extended squitter receiving apparatus 1a has a problem that a necessary extended squitter cannot be decoded due to unnecessary data decoding.

Michael C. Stevens “Secondary Surveillance Radar” 1998, ISBN 0-89006-292-7

  In general, when an aerial radar device installed on the ground makes a question and answer with an aircraft, a directional antenna can be used to set a question answering schedule. This can limit the signal detection efficiency.

  However, since the extended squitter receiving apparatus 1a installed on the ground uses an omnidirectional antenna, the extended squitter is received asynchronously. In such an extended squitter receiver 1a, the frequency of garble (radio wave interference) may increase. In addition, the extended squitter receiving apparatus 1a cannot perform level suppression processing (STC) on a short-range device or the like because there is no reception schedule.

  For this reason, in the extended squitter receiving apparatus 1a, when the number of signals to be received increases, the erroneous detection of received signals as shown in FIG. 7 increases and the signal detection rate may decrease.

  Therefore, the present invention provides a signal receiving apparatus that prevents a decrease in signal detection rate due to erroneous detection.

  A signal receiving apparatus according to the present invention is a signal receiving apparatus that detects a signal including a predetermined preamble and a data block from a received signal. When a predetermined preamble is detected from a received signal, a data block following the detected preamble is detected. A first processing means for decoding and detecting a new preamble during decoding of the data block of the received signal; and a first processing means for detecting a predetermined block from the new received signal while decoding the data block of the received signal. And a second processing means for decoding a data block following the detected preamble and canceling the detection of a new preamble during the decoding process.

  According to the present invention, it is possible to prevent a decrease in signal detection rate due to erroneous detection.

It is the schematic explaining the extended squitter receiver which concerns on the best embodiment of this invention. It is a functional block diagram explaining the structure of the signal processing part of the extended squitter receiver shown in FIG. It is a figure explaining the process in the signal processing part shown in FIG. It is the schematic explaining the conventional extended squitter receiver. It is a figure explaining the format of an extended squitter. It is a functional block diagram explaining the structure of the signal processing part of the extended squitter receiver shown in FIG. It is a figure explaining the process in the signal processing part shown in FIG.

  A signal receiving apparatus according to the best embodiment of the present invention will be described with reference to FIGS. Hereinafter, the signal receiving device will be described as the extended squitter receiving device 1. In the following description, the same components as those in the related art will be described with the same reference numerals.

  The extended squitter receiving apparatus 1 shown in FIG. 1 is installed in the ground station in the same manner as the extended squitter receiving apparatus 1a described above with reference to FIG. The extended squitter receiving apparatus 1 receives and processes the extended squitter transmitted from the transponder 2 provided in the aircraft, and receives the antenna 10, a receiving unit 11 that receives a signal such as an extended squitter via the antenna 10, and a reception And a signal processing unit 12 connected to the unit 11 for processing the received signal.

  As shown in FIG. 2, when the first preamble detection unit 123a detects the preamble of the extended squitter from the received data, and the first preamble detection unit 123a detects the preamble of the extended squitter, the signal processing unit 12 First processing means 123 for decoding the extended squitter data block by the decoding processing means 123b, and the first processing means 123 detects the preamble of the extended squitter from the received data by the second preamble detecting means 124a during the decoding process, and the second When the preamble of the extended squitter is detected by the preamble detection unit 124a, the second processing unit 124 decodes the data block of the extended squitter by the second decoding processing unit 124b, and the first processing unit 123 or the second processing unit 124 Decode data Decode data selection means 125 for selecting and outputting, enable signal output means 126 for outputting an enable signal used for selecting valid decode data, and decode data output means 127 for outputting decode data in accordance with the enable signal. ing.

  The first preamble detection unit 123a receives the reception data received by the antenna 10 from the reception unit 11, and receives the first decoding completion signal for determining that the decoding process is completed from the first decoding processing unit 123b. Further, the first preamble detection means 123a detects the preamble from the received data when it is set to “during detection process”, and detects the presence or absence of the preamble as the first detection result as the first decode processing means 123b and the second preamble detection. Output to the means 124a.

  Here, in the first preamble detection unit 123a, the first decoding processing unit 123b is “waiting for detection processing” while the decoding process is being performed, and the preamble cannot be detected. That is, the first preamble detection means 123a sets detection prohibition until the first decode completion signal for notifying the end of the decoding process is input from the first decode processing means 123b after detecting the preamble, thereby detecting the preamble. Do not execute processing.

  On the other hand, in the first preamble detection unit 123a, when the first decoding processing unit 123b is not in the decoding process, it is “detecting process”, and the preamble detection process can be performed. Therefore, the first preamble detection unit 123a sets the detection process during the period from the input of the first decoding completion signal from the first decoding processing unit 123b until a new preamble is detected, and executes the preamble detection process. .

  The first decoding processing unit 123b receives the reception data received by the antenna 10 from the receiving unit 11, and receives the preamble detection result from the first preamble detection unit 123a. Also, when the first decoding processing unit 123b receives the detection result with the detection of the preamble from the first preamble detection unit 123a, the first decoding processing unit 123b detects and decodes the data block of the extended squitter from the received data.

  Further, the first decoding processing means 123b outputs a first decoding completion signal indicating that the decoding processing has been completed. Specifically, the first decoding processing unit 123b notifies the end of the decoding process of the data block when the decoding process of the data block is completed, and transmits a first decoding completion signal that permits the restart of the preamble detection to the preamble detecting unit 121. Output to. As described with reference to FIG. 5, the preamble of the extended squitter is 8 μs, and the data block is 112 μs of data that follows the preamble. Therefore, the first decoding processing unit 123b can determine the end of the decoding process of the data block by using the preamble and the data length of the data block (120 μs).

  The second preamble detection unit 124a receives the reception data received by the antenna 10 from the reception unit 11, the preamble detection result from the first preamble detection unit 123a, and the decoding process is completed from the second decoding processing unit 124b. The second decoding completion signal for determining this is input. Further, the second preamble detection unit 124a detects the preamble from the received data when it is not set to “detection prohibition”, and outputs the presence / absence of the preamble to the second decoding processing unit 124b as a detection result.

  Here, since the first preamble detection unit 123a has priority over the second preamble detection unit 124a, the second preamble detection unit 124a is “detection prohibited” when the first preamble detection unit 123a is “in the process of detection”. The preamble cannot be detected. Further, the second preamble detection means 124a cannot detect the preamble because the second preamble detection means 124a is “detection prohibited” even while the second decoding processing means 124b is performing the decoding process. In other words, the second preamble detection unit 124a receives the second decoding completion signal for notifying the end of the decoding process from the second decoding processing unit 124b even if the first preamble detection unit 123a is “detection prohibited”. During this period, the preamble detection process is not executed.

  On the other hand, when the first preamble detection unit 123a is “detection prohibited” and the second decoding processing unit 124b is not performing decoding processing, the second preamble detection unit 124a is “detecting processing” and the preamble detection processing Can be performed. That is, the second preamble detection unit 124a sets the detection process during the period from the input of the second decoding completion signal from the second decoding processing unit 124b to the detection of a new preamble, and executes the preamble detection process. .

  The second decoding processing unit 124b receives the reception data received by the antenna 10 from the receiving unit 11, and inputs the detection result of the preamble from the second preamble detection unit 124a. Further, when the second decoding processing unit 124b receives the detection result with the detection of the preamble from the second preamble detection unit 124a, the second decoding processing unit 124b detects and decodes the data block of the extended squitter from the received data.

  Further, the second decoding processing means 124b outputs a second decoding completion signal indicating that the decoding processing has been completed. Specifically, the second decoding processing unit 124b notifies the end of the decoding process of the data block when the decoding process of the data block is completed, and sends a second decoding completion signal that permits the restart of the preamble detection to the preamble detecting unit 121. Output to. The second decoding processing unit 124b can also determine the end of the data block decoding process using the unified data length (120 μs) of the extended squitter (preamble and data block).

  The decode data selection means 125 inputs the first decode data decoded by the first decode processing means 123b and the second decode data decoded by the second decode processing means 124b. The decode data output means 125 receives the second decode completion signal from the second decode processing means 124b, and when the second preamble detection means 124a permits detection of the preamble by the second decode completion signal, the second decode completion signal is inputted. Data is output, otherwise the first decoded data is output.

  The enable signal output means 126 receives the first decoding completion signal from the first decoding processing means 123b, and receives the second decoding completion signal from the second decoding processing means 124b. The enable signal output means 126 outputs an enable signal for permitting the output of decoded data when the first decode completion signal or the second decode completion signal for permitting detection of the preamble is input.

  When the decode signal output unit 127 receives an enable signal permitting the output of decode data from the enable signal output unit 126, the decode data output unit 127 outputs the decode data input from the decode data selection unit 125 to the monitoring processing unit 13 as an extended squitter detected.

  Here, in FIG. 2, the case where the two processing units of the first processing unit 123 and the second processing unit 124 are provided has been described as an example, but the number of processing units included in the signal processing unit 12 is not limited. For example, even when two processing units are provided, if the detection rate of the extended squitter is low, the detection rate can be improved by providing a plurality of processing unit blocks.

  An example when the extended squitter is received after the short response is received will be described with reference to FIG. FIG. 3A shows the received data input from the receiving unit 11 by the signal processing unit 12, and it can be seen that the extended squitter is received immediately after receiving the short response.

  At the time of receiving the short response, the state of the first processing unit 123 is “detection processing in progress” by the first preamble detection unit 123a. However, when the preamble of the short response is detected, the first decoding processing unit 123b “ “The decoding process is in progress”, and the first preamble detection unit 123a becomes “detection prohibited” (FIG. 3B). In the second processing unit 124, the second preamble detection unit 124a is "detection prohibited" while the first processing unit 123 is "detecting processing", but the first processing unit 123 is "decoding process". Then, “detection processing is in progress” (FIG. 3F).

  When the preamble is detected by the first preamble detection means 123a (FIG. 3C), the received data is decoded by the first decoding processing means 123b. The decode data output means 127 outputs the reception data decoded by the first decode processing means 123b by an enable signal output from the enable signal output means 126 in response to the first decode completion signal at the end of decoding (FIG. 3 (k)). ) And determined as mode S signal data (short response data) (FIGS. 3D, 3E, and 3J).

  When the preamble is detected by the second preamble detection unit 124a (FIG. 3G), the received data is decoded by the second decoding processing unit 124b. The decode data output means 127 outputs the reception data decoded by the second decode processing means 124b by an enable signal output from the enable signal output means 126 in response to the second decode completion signal at the end of decoding (FIG. 3 (k)). ) And determined as mode S signal data (extended squitter data) (FIG. 3 (h), (i), (j)).

  In the conventional extended squitter receiving apparatus 1a described with reference to FIG. 7A, when the extended squitter is received during the decoding process of the short response data block, the preamble of the extended squitter cannot be detected. On the other hand, in the extended squitter receiving apparatus 1 according to the embodiment of the present invention, as shown in FIG. 2, the first processing means 123 and the second processing means 124 are used to execute the preamble detection process and the decoding process. ing. That is, as shown in FIG. 3, during the decoding process by the first decoding processing unit 123b of the first processing unit 123, the preamble is detected by the first preamble detecting unit 124a of the second processing unit 124. Therefore, even when the extended squitter is received immediately after receiving the short response, the extended squitter can be detected and decoded.

  As described above, the extended squitter receiving apparatus 1 according to the embodiment of the present invention includes the first processing unit 123 and the second processing unit 124 that detects the preamble when the first processing unit 123 is performing the decoding process. ing. Thus, when the first processing unit 123 is processing the extended squitter that has already been received and a new extended squitter cannot be processed, the second processing unit 124 can process the detection and analysis of the extended squitter. . Therefore, in the extended squitter receiving apparatus 1 according to the embodiment of the present invention, it is possible to prevent a decrease in signal detection rate due to erroneous detection.

DESCRIPTION OF SYMBOLS 1 ... Extended squitter receiver 10 ... Antenna 11 ... Reception part 12 ... Signal processing part 123 ... 1st processing means 123a ... 1st preamble detection means 123b ... 1st decoding processing means 124 ... 2nd processing means 124a ... 2nd preamble detection Means 124b ... second decoding processing means 125 ... decoded data selection means 126 ... enable signal output means 127 ... decoded data output means 13 ... monitor processing section 2 ... transponder 20 ... antenna 21 ... transmission / reception section 22 ... signal processing section

Claims (2)

The received signal is composed of a first pulse to a fourth pulse each having a pulse width of 0.5 μs, from the rising edge of the first pulse to the rising edge of the second pulse is 1 μs, and from the rising edge of the first pulse to the rising edge of the third pulse. Is a signal receiving device that detects a signal including a preamble that is 3.5 μs, 4.5 μs from the rising edge of the first pulse to the rising edge of the fourth pulse, and a data block of 112 μs following the preamble ,
When detecting the preamble from the received signal, a first processing means to stop the detection of the new preamble with decodes the data of 112μs following the detected preamble, while decoding the data of the received signal,
During decoding the data block of the first processing means receiving signals, detects the preamble from the new received signal, thereby decoding the data of 112μs following the detected preamble, a new preamble during decoding A second processing means for canceling the detection;
A signal receiving apparatus comprising: The received signal is composed of a first pulse to a fourth pulse each having a pulse width of 0.5 μs, from the rising edge of the first pulse to the rising edge of the second pulse is 1 μs, and from the rising edge of the first pulse to the rising edge of the third pulse. Is a signal receiving device that detects a signal including a preamble that is 3.5 μs, 4.5 μs from the rising edge of the first pulse to the rising edge of the fourth pulse, and a data block of 112 μs following the preamble ,
When the preamble is detected from the received signal, the data of 112 μs following the detected preamble is decoded, and a plurality of processing means for stopping detection of a new preamble during decoding of the received signal data are provided,
A priority is set for each processing means, and each processing means performs preamble detection only when another processing means having a higher priority is decoding data .

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