JP2586801B2 - Receiver for Takan equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
N: Navigation assistance) It relates to a receiver for a Takan device which receives a query pulse from the device.

[0002]

2. Description of the Related Art Conventionally, distance measurement in a Takan device is
Interrogation pulse (X mode 1) emitted from the on-board Takan device
The ground takan device receives 2 μs and a 36 μs Y mode pulse) and delays it with a certain response delay time to make an interrogation pulse of (X mode 50 μs, Y mode 56 μs) and then (X mode 12 μs, Y This is transmitted to the on-board Takan device as a response pulse in mode 30 μs). The onboard Takan device receives this response pulse and calculates the distance according to the principle of radar.

Here, assuming that the time from when the onboard Takan device receives the inquiry pulse to the response pulse is T, the distance from the onboard Takan device to the ground Takan device is R, and the speed of light is C, T = 2R / C + Since the relationship of (response delay time) is obtained, the distance R can be obtained by obtaining T.

A method in which an on-board Takan device detects its own response pulse from among 2700 ± 90 pulse pairs / second transmitted from a ground Takan device uses a gate (for example, 16 μs) of a response pulse to an interrogation pulse at a distance of 0 nautical miles (hereinafter, referred to as a distance). ,
"Nautical miles" is represented by a symbol NM) and shifted at a constant speed from 300 NM. If the number of response pulses is obtained, for example, 50% or more of the number of interrogation pulses, it is recognized as its own response pulse. ing.

[0005] Normally, the transmission pulse 270 of the ground TACAN device is used.
0 ± 90 pulse pairs / sec is a random pulse since it is made from the decode pulse generated from the receiver noise. Therefore, the probability of a pseudo response pulse of noise with respect to the interrogation pulse is small, and does not reach 50% recognized as a response pulse.

By the way, a receiver for a ground takan device installed in an airfield in which buildings such as tall mountains and hangers are arranged in the vicinity of the airfield has a considerably large level generated by an interrogation pulse of the onboard device and the interrogation pulse. Multipath and receive. This multipath causes a high-probability correlation with a random pulse generated from reception noise, and generates, for example, a distance mislock (erroneous indication or fluctuation) and an off flag (no indication) around an airfield (within 10 NM). Cause.

FIG. 3 is a block diagram showing a basic configuration of a conventional receiver for a ground-based takan device. FIG. 4 is a timing chart showing a waveform diagram relating to the signal processing. FIG. 4A shows a case where the aircraft is far beyond 20 NM, and FIG. 4B shows a case where the aircraft is close within 20 NM. Is shown.

First, referring to FIG. 3, this receiver 3
Is captured from the antenna 1 and the duplexer 2
With respect to a receiver input signal transmitted through the receiver, a decoding pulse b obtained by each processing described later is transmitted to the transmitter 4. The receiver output signal from the transmitter 4 is fed back to the duplexer 2. The receiver 3, according to the receiver input signal including the received noise and interrogating pulse, by using a later-described control signal f, having a sensitivity to random decoding pulse b is Ru is generated from the receiver noise. However, the sensitivity here is the
The response rate is 70% for the Takan device.
Is shown. Also, the decode pulse b
Is generated from the receiver noise.
The question pulse above has a high probability of being decoded
ing.

That is, the receiver 3 includes a preselector 11 and a mixer amplifier 12 on the input first stage side. Receiving
Amplifier 13 as amplifying means for amplifying the machine input signal
Consists of an amplifier whose gain is controlled by a voltage, a linear amplifier, a narrow-band detector of 260 kHz, and a detector coupled to the linear amplifier. These components are a reception signal a and an IF video signal (detection signal). D) input and output the control signal f .

[0010] More specifically, the decoder circuit 14 that receives the received signal a from the IF amplifier 13 receives the received signal a.
It has a function of decoding a paired pulse of X mode 12 μs and Y mode 36 μs from (including the receiver noise N and the interrogation pulse Q). The decode pulse b output from the decoder circuit 14 is composed of both the random pulse R generated from the receiver noise and the query decode pulse D of the query pulse. Further, the decoding circuit 14 has a function of suppressing the decoding for 60 μs from the generation of the interrogation decode pulse D, and a function of extending the decoding suppression time to about 150 μs when there is a multipath M.

The AGC circuit 15 to which the decode pulse b is input has an AGC voltage c for controlling the gain of the IF amplifier so that the decode pulse b is 2700 ± 90 pulses / sec.
(For example, +5 VDC). The detection signal d from the detector coupled with the linear amplifier of the IF amplifier 13 is high when the input of the receiver 3 is at a large level (for example, -80 dBm).
Above).

First pulse GTC for inputting detection signal d
(Gain Time Constant) Circuit 16
Is -7 when the detection signal d is -70 dBm or more.
A voltage equal to or greater than 0 dBm is integrated to generate a GTC voltage e. The adder 17 adds the AGC voltage c and the GTC voltage e, generates a control signal f, and controls the gain of the IF amplifier 13. In general, the time constant τ of integration is selected to be about τ = 100 μs because the time of the multipath M is 200 μs or less.

Therefore, for example, if the suppression gain for the multipath M is set to 20 dB, the signal of −60 dBm becomes 20 dB.
The signal level is attenuated by B and becomes about the same as the signal level of -80 dBm. However, since the noise level is also suppressed by 20 dB, the S / N ratio does not change, but since the triggering level TL is constant (0.7 V), noise and small signal levels are not triggered.

[0014] reception level P _r of the ground TACAN apparatus for receiving a question level P _t about 1kW from the aircraft differs significantly depending on the distance R, and the wavelength and lambda, · P _r = P _t
(Λ / 4πR) ² . When this is _expressed in logarithm, P _r = P _t + 20 · log (λ / 4πR).

Therefore, if the wavelength λ is λ = 0.3 m,
-12.4 dBm, 10N when the distance R is 100 m
-57.8 dBm for M,-for 20 NM
63.8 dBm, -83.8 dB for 200 NM
In the case of m and 300 NM, it becomes -87.3 dBm.

In general, the reception level of a terrestrial TACAN device is-
It has an allowable range of 105 to -10 [dBm], and the region where the multipath M is generated by the interrogation pulse Q of the aircraft is within 20 NM, that is, the range of -63.8 to -10 [dBm]. As described above, even if a suppression gain of about 20 dB is given by the first pulse GTC circuit 16, it is within 2NM (20N
At 20 dB · up with respect to M, a multi-pass M occurs between the paired pulses (X mode 12 μs, Y mode 36 μs), which is the same as the state in which a question exists.

Therefore, as shown in FIG.
At relatively short distances within 0 NM, the receiver noise N in front of the interrogation pulse Q and the multipath M due to the interrogation pulse Q show a high probability correlation, so that the interrogation decode pulse D It occurs randomly between the first pulse and the second pulse of Q.

As a result, a normal response pulse (normal interrogation decode pulse D ') to the interrogation pulse Q is generated by a random interrogation decode pulse D generated by the receiver noise N and the multipath M, thereby achieving a 60 μs decoding suppression function. Blanked, distance off flag (no indication)
Becomes Alternatively, since the decode pulse b fluctuates due to noise, a distance mislock (erroneous instruction or fluctuation) occurs. This is particularly noticeable when the interval between the first pulse and the second pulse of the interrogation pulse is longer in the Y mode than in the X mode. By the way, according to the field information,
5NM when distance mislock or off flag occurs
Within.

Incidentally, a technique related to a well-known Takan apparatus is disclosed in Japanese Patent Application Laid-Open No. 54-52493 and Japanese Utility Model Application Laid-Open No. 3-175.
No. 85, for example.

[0020]

The above-mentioned first pulse G
In a receiver for a ground-based takan device including a TC circuit, when the on-board takan device is at a relatively short distance, that is, especially within 5 NM, a distance mislock (incorrect instruction or fluctuation) due to the influence of multipath due to an interrogation pulse. And an OFF flag (no indication) occurs.

[0021] In addition, the flight inspection is usually carried out once every three months in the Takan device. However, if a mislock occurs, the flight inspection is extended, and the cost associated therewith tends to be increased. There is.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. The technical problem of the present invention is that the multipath can be suppressed even when the partner TACAN device is at a relatively short distance. It is an object of the present invention to provide a receiver for a Takan device which can remove a distance mislock caused by correlation with the receiver.

[0023]

According to the present invention SUMMARY OF THE INVENTION In response to the receiver input signal including the received noise and interrogating pulse, Ru random decoding pulse is generated from Ri受 Shin machine noise by the use of the control signal sensitive A level detection circuit for detecting the interrogation pulse from a receiver input signal based on a predetermined level determined according to a range in which multipath is generated by the interrogation pulse and the level of the interrogation pulse, A timing circuit for measuring a time from the fall of the first interrogation pulse to immediately before the rise of the second interrogation pulse in the interrogation pulse detected by the level detection circuit to generate a timing signal, and synchronizing with the timing signal Receiving circuit for a takan device including a control voltage generating circuit for generating a control voltage of a specified level, and a circuit for generating a control signal using the control voltage. The machine can be obtained.

According to the present invention, in the receiver for a takan device, the timing circuit generates a start pulse delayed by a pulse width from the first interrogation pulse detected by the level detection circuit, and generates a second pulse. A stop pulse is generated immediately before the rise of the interrogation pulse, and the control voltage generation circuit
A receiver for a takan device that generates a pulse-like control voltage at the timing of a start pulse and a stop pulse is obtained.

Further, according to the present invention, any one of the above hawks
In emission device receiver inputs the receiver input signal containing interrogation pulse, and amplifying means for amplifying the receiver input signal, a predetermined level multipath determined according to the range generated by interrogation pulse and the interrogation pulse Between the fall of the first interrogation pulse in the input signal of the receiver and immediately before the rise of the second interrogation pulse, the amplification means is controlled by a control signal in which the gain of the amplification means is suppressed to the maximum. Thus, a receiver for a takan device having a control means for controlling the same is obtained.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a basic configuration of a receiver for a terrestrial tucan apparatus according to one embodiment of the present invention.

[0028] In this receiver 3, according to the receiver input signal including the received noise and interrogating pulse, by using a later-described control signal f, a random decoder pulse b is sensitivity that will be generated from the receiver noise Since the configuration is basically the same as that described with reference to FIG. 3, the same components are denoted by the same reference numerals, and description thereof is omitted.
Only the differences will be described.

The receiver 3 for the ground-side takan device further uses the IF amplifier 13 from the input signal of the receiver based on the level of the interrogation pulse and a predetermined level determined according to a range within 20 NM in which multipath is generated by the interrogation pulse. And a level detection circuit 21 that detects an interrogation pulse from the detection signal d and outputs a detection signal g from the falling edge of the first interrogation pulse in the interrogation pulse to immediately before the rising edge of the second interrogation pulse A timing circuit 22 that measures the time of
And a control voltage generating circuit 23 for generating a pulse-like control voltage i of a specific level synchronized with the control voltage generator.

The level detector 21 receives a detection signal d (generated at -80 dBm or more) from a detector coupled to the linear amplifier of the IF amplifier 13 and outputs a level -63. Detection is performed at 8 dBm (actually, -70 dBm) or more, and a detection signal g is output.

In the timing circuit 22, the level detector 2
A start pulse is generated with a delay of the pulse width from the first interrogation pulse of the detection signal g output from 1 (4 μs since the pulse width is 3.5 μs ± 0.5 μs), and a second pulse is generated.
A stop pulse is generated just before the rise of the interrogation pulse. The start pulse is generated at such a timing that the suppression voltage is not applied to the IF amplifier 13 within a pulse width of 3.5 ± 0.5 μs, and the stop pulse is such that the suppression voltage disappears immediately before the second interrogation pulse is received. Generated at the timing. Actually, this is performed in consideration of the response time of the IF amplifier 13 of about 1 μs.

The control voltage generation circuit 23 generates a pulse-like control voltage i at the timing of the start and stop pulses of the timing circuit 22. This pulse-like control voltage i
Is generated from the start pulse to the stop pulse until the gain of the IF amplifier 13 is 7 to 8
dB / 0.1V attenuation. By the way, 80d
The suppression of B may be 1.2 V or more.

In the case of the terrestrial TACAN receiver having such a configuration, the overall gain control is performed by the AGC circuit 15.
The suppression gain of the multipath generated by the interrogation pulse is the first
The pulse GTC circuit 16 responds to the signal from the fall of the first interrogation pulse to the time immediately before the rise of the second interrogation pulse.
A control signal f is generated by the adder circuit 17 so that the gain of the amplifier 13 is suppressed to a maximum (80 dB or more), and the control signal f is controlled.
The IF amplifier 13 is controlled by the signal f. That is, the addition circuit 1
7, the pulse-like control voltage i output from the control voltage generation circuit 23 is used, and this pulse-like control voltage i is used as the AGC voltage c from the AGC circuit 15 and the first pulse GTC circuit 16.
The control signal f is generated after adding the GTC voltage e to the GTC voltage e. The IF amplifier 13 controlled by the control signal f
The gain is minimized.

Therefore, the AGC circuit 15, the first pulse GT
C circuit 16, level detector 21, timing circuit 22,
The control voltage generation circuit 23 and the addition circuit 17 function as control means for maximally suppressing the gain of the IF amplifier 13. Incidentally, the use of the control signal f here
For example, if there is no interrogation pulse,
Through the IF amplifier 13 and the decoder circuit 14
Generates pulse b, and sets the receiver
IF amplifier 13 and decoder times
A decode pulse b is generated via the path 14, and in any case,
Also control the number of pulses to 2700 ± 90 pps.
When controlling with an AGC signal (functionally,
Similar to the voltage c)].

FIG. 2 is a timing chart showing a waveform chart relating to the signal processing of the receiver 3 shown in FIG. 1, and FIG. 2A shows a case where the aircraft is far exceeding 20 NM. B) shows the case where the aircraft is close to within 20 NM.

2 (A) and 2 (B), according to the receiver 3, the pulse-like control voltage i (8 μs in the X mode and 32 μs in the Y mode) is applied to the adder circuit 17 even in the case of near 20 NM. Is input, and the IF
By controlling the amplifier 13 with the control signal f, it is understood that the interrogation decode pulse D appears as a normal response pulse to the pair of interrogation pulses Q.

[0037]

As described above, according to the receiver for a takan apparatus of the present invention, multipath is suppressed even when a partner takan apparatus is at a relatively short distance, and multipath of receiver noise and interrogation pulse is obtained. , The distance mislock or the OFF flag can be eliminated. In addition, since there is no mislocking of the distance, the flight inspection of the TAKAN device can be performed at a regular time, and an increase in cost due to extension of the inspection can be avoided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a receiver for a terrestrial takan device according to one embodiment of the present invention.

FIG. 2 is a timing chart showing a waveform chart related to signal processing of the receiver for the ground-based takan device shown in FIG. 1, where (A) shows a case where the aircraft is far exceeding 20 NM,
(B) shows the case where the aircraft is close to within 20 NM.

FIG. 3 is a block diagram showing a basic configuration of a conventional receiver for a terrestrial takan device.

FIG. 4 is a timing chart showing a waveform chart related to signal processing of the receiver for the terrestrial takan device shown in FIG. 3, where (A) shows a case where the aircraft is far exceeding 20 NM,
(B) shows the case where the aircraft is close to within 20 NM.

[Description of Signs] 1 Antenna 2 Duplexer 3 Receiver 11 Preselector 12 Mixer amplifier 13 IF amplifier 14 Decoder circuit 15 AGC circuit 16 First pulse GTC circuit 17 Addition circuit 21 Level detection circuit 22 Timing circuit 23 Control voltage generation circuit

Claims (3)

(57) [Claims] 1. A response to the receiver input signal including the received noise and interrogation pulse, on the ground TACAN system receiver having a sensitivity to random decoding pulses Ru are generated from by Ri受 Shin machine noise to the use of the control signal A level detection circuit that detects the interrogation pulse from the receiver input signal based on a predetermined level determined according to a range in which multipath is generated by the interrogation pulse and the level of the interrogation pulse; A timing circuit for measuring the time between the fall of the first interrogation pulse and immediately before the rise of the second interrogation pulse in the interrogation pulse to generate a timing signal, and a control voltage of a specific level synchronized with the timing signal And a circuit for generating the control signal using the control voltage. Equipment receiver. 2. The receiver for a takan device according to claim 1, wherein the timing circuit generates a start pulse delayed by a pulse width from a first interrogation pulse detected by the level detection circuit. 2. A receiver for a takan device, wherein a stop pulse is generated immediately before the rise of the second interrogation pulse, and the control voltage generation circuit generates a pulse-like control voltage at the timing of the start pulse and the stop pulse. 3. The reception for a takan device according to claim 1 or 2.
In machine, and inputs the receiver input signal containing the interrogating pulse, amplification means and a predetermined level and the interrogation pulse which defines according to the range the multipath is generated by pre-Symbol interrogating pulse for amplifying the receiver input signal between the level and the falling of the in the receiver input signal first interrogation pulses based on the rising immediately before the second interrogation pulses, the gain of the amplifying means can be suppressed maximally <br /> TACAN system receiver, characterized in that a control means for controlling the amplification means by a control signal.