JP5025544B2 - DME ground equipment - Google Patents

Description

  The present invention relates to a DME (Distance Measuring Equipment) ground device that is a radio navigation facility.

  The DME ground device transmits a response pulse after a lapse of a certain time after receiving an interrogation pulse from the aircraft. The aircraft can measure the distance from the DME ground unit based on the time from transmission of the interrogation pulse to reception of the response pulse. In addition, each pulse contains various coded information and is an indispensable device for the safe operation of an aircraft. A technology related to the DME ground device has been filed, for example, as Patent Document 1.

  The DME ground device must process interrogation signals from multiple aircrafts that are in the radio range. The distance between the aircraft and ground equipment ranges from a close range to a few miles, and the radio wave reception intensity changes greatly accordingly. In order to cope with this, the system is required to have a performance capable of reliably receiving and processing a question signal with a minimum reception sensitivity just below a question signal with a maximum maximum reception sensitivity.

One index indicating the performance of DME ground equipment is recovery time. This recovery time is the time required to receive a weak pulse after receiving a strong pulse, and specifically, a strong single pulse that precedes a weak received pulse pair by 8 microseconds. It is stipulated that even if there is, it is possible to respond reliably.
Japanese Patent Application No. 2007-145282

  By the way, the DME ground device has a function of monitoring the transmission pulse (response pulse) waveform, the transmission level, the system delay time, the response efficiency, and the like, and the normality of the transponder is confirmed by this function. In order to realize this function, a monitoring control unit is provided separately from the transponder unit. For example, in order to test whether or not the recovery time requirement is satisfied, it is necessary to generate a single pulse by a pulse generator in addition to generating a pseudo interrogation pulse that is regarded as an interrogation pulse of an aircraft by the supervisory control unit.

However, in order to carry out this test, a dedicated measuring instrument such as a pulse generator is required, which complicates the apparatus accordingly. This also leads to an increase in system cost, so some measures need to be taken.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a DME ground device capable of measuring the recovery time with a simple structure.

  In order to achieve the above object, according to an aspect of the present invention, in a DME ground device including a transponder unit that transmits a response pulse to a received interrogation pulse, a single pulse and a subsequent level lower than the single pulse and at a specified interval are followed. A pulse pair for generating a pulse pair to be transmitted, and transferring the single pulse and the pulse pair to the transponder unit, and monitoring a response pulse for the pulse pair transferred to the transponder unit to test the recovery time of the transponder unit A DME ground device comprising a test control unit is provided.

  By taking such means, a pulse for testing the recovery time is internally generated in the DME apparatus, so that the recovery time can be tested with a simple configuration. In particular, after a single pulse and a pulse pair of the same level are generated in succession, the recovery time is ensured by abruptly attenuating the level of the pulse pair by a high-speed switching element using a PIN diode or the like immediately after the single pulse is transmitted. It is possible to generate a pulse that can be measured immediately.

  According to the present invention, it is possible to provide a DME ground device capable of measuring the recovery time with a simple configuration.

  FIG. 1 is a functional block diagram showing an embodiment of a DME ground device according to the present invention. The DME ground device 10 includes a transponder unit 20 that transmits a response pulse to the received interrogation pulse, and a monitoring control unit 30 that monitors the state of the transponder unit 20. Among these, the transponder unit 20 performs wireless communication with an aircraft (not shown) via the antenna 11. The supervisory control unit 30 generates a pulse for testing the recovery time of the transponder unit 20. This pulse consists of a single pulse followed by a pulse pair, and is transferred to the transponder unit 20 via the directional coupler 12 inside the apparatus. At this time, the transfer level of the pulse pair is attenuated by the attenuator 40 provided in the middle of the transfer path.

  In FIG. 1, an interrogation pulse from an aircraft reaches a transponder unit 20 via an antenna 11 and a directional coupler 12, and is further sent to an IF conversion unit 22 via a circulator 21. The IF conversion unit 22 converts the received pulse into an IF (Intermediate Frequency) signal. The IF signal is converted into data by an analog / digital (AD) conversion unit 23 and then processed by the processing unit 24. The processing unit 24 generates a response pulse for the received interrogation signal. The response pulse is amplified by the pulse transmission unit 25 and returned to the aircraft via the circulator 21, the directional coupler 12, and the antenna 11.

  Incidentally, the monitoring control unit 30 includes a test control unit 30a, a pulse generation unit 30b, and a D / A conversion unit 30c as processing functions according to this embodiment. Of these, the pulse generator 30b generates a single pulse and a pulse pair. If these pulses can have an appropriate level difference and an appropriate time interval, a pulse for testing the recovery time of the transponder unit 20 can be internally generated. The single pulse is set to a level corresponding to the maximum reception sensitivity of the transponder unit 20, and the pulse pair is set to a level that is just below the minimum reception sensitivity. Further, the time interval between both pulses is set to about 1 microsecond.

  The pulse generator 30b stores digital waveform data in an internal waveform memory (not shown) or the like, and reads out this data and returns it to an analog waveform by a D / A (digital / analog) converter 30c. And generate a pulse pair. Of these, the pseudo interrogation pulse pattern is written in the pulse pair. The level difference between these pulses is realized by instantaneously changing the attenuation amount of the attenuator 40.

  The test control unit 30a monitors a response pulse to the pulse pair (pseudo question pulse) transferred to the transponder unit 20 by the pulse generation unit 30b. Without this response pulse, it can be seen that the transponder unit 20 has not recovered from the arrival of a single pulse. It is possible to test whether or not the transponder unit 20 satisfies the required specifications by setting the specified interval between the single pulse and the pulse pair and the level difference to a specified value.

  FIG. 2 is a schematic diagram showing a pulse for measuring the recovery time of the transponder unit 20. In order to test the recovery time, according to regulations, it is necessary to generate a single pulse 8 microseconds before the pseudo interrogation pulse. Further, it is necessary to increase the transmission level of the single pulse to about 60 dB higher than the minimum reception sensitivity of the transponder unit 20. Thus, it is difficult to generate a pulse that shows a sudden level change by the D / A converter 30c.

  Therefore, in this embodiment, the attenuator 40 is formed by a switching element using a PIN diode, and the pulse level after being output from the D / A converter 40 is controlled. In the recovery time test, it is necessary to generate a pulse pair 8 microseconds after the start of generation of a single pulse. Since the pulse width of the single pulse is 7 microseconds or less, it is necessary to realize switching (level switching) of the attenuator 40 in 1 microsecond or less. This is possible for the first time by using a PIN diode.

  As shown in FIG. 2, in the recovery time test, it is measured how much the minimum reception sensitivity of the pseudo interrogation signal deteriorates depending on whether or not there is a single pulse. The degradation time difference is expressed in dB, and it is possible to test the recovery time of the transponder unit 20 by verifying whether the value satisfies a specified value. The level of the pseudo interrogation signal may be varied according to the response efficiency (70% or more) of the transponder unit 20. In such a mode, the difference from the minimum level (minimum reception sensitivity) may be measured.

  As described above, in this embodiment, the attenuator 40 using a high-speed PIN switch generates a weak pulse pair for testing and a strong single pulse preceding this in microsecond order within the DME apparatus. Is possible. This eliminates the need for a complicated external measuring instrument, makes it possible to easily measure the recovery time, and to reduce the adjustment time and cost. From these facts, it becomes possible to provide a DME ground device capable of measuring the recovery time with a simple configuration.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

The functional block diagram which shows embodiment of the DME ground apparatus concerning this invention. The schematic diagram which shows the pulse for measuring the recovery time of the transponder part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... DME ground apparatus, 20 ... Transponder part, 30 ... Monitoring control part, 11 ... Antenna, 12 ... Directional coupler, 21 ... Circulator, 22 ... IF conversion part, 23 ... Analog / digital conversion part, 24 ... Processing part , 25 ... Pulse transmission unit, 30a ... Test control unit, 30b ... Pulse generation unit, 30c ... D / A (digital / analog) conversion unit, 40 ... Attenuator

Claims (2)

In a DME (Distance Measuring Equipment) ground device having a transponder unit that sends a response pulse to a received inquiry pulse,
A waveform memory for storing digital waveform data for generating a single pulse and a pulse pair written with a pseudo interrogation pulse pattern;
The waveform data is read from the waveform memory, the read waveform data is converted into an analog waveform, and a single pulse and a pulse pair of the same level are continuously generated, and then the level of the pulse pair is set immediately after the single pulse is transmitted. A pulse generator that abruptly attenuates and transfers the single pulse and the pulse pair that follows the single pulse at a lower level and at a specified interval to the transponder unit;
A test control unit that monitors a response pulse to the pulse pair transferred to the transponder unit and tests a recovery time of the transponder unit ;
The pulse generation unit includes an attenuator that is a switching element using a PIN diode (p-intrinsic-n Diode) provided in a path along which the single pulse and the pulse pair are transferred to the transponder unit. The DME ground device is characterized in that a predetermined level difference is provided between the single pulse and the pulse pair by increasing the attenuation amount of the attenuator within the period . The specified interval is 1 microsecond or less,
The DME ground device according to claim 1, wherein the prescribed level difference is 60 dB or more .

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