JP2012117958A - Tactical air navigation ground device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a peak value of transmission power after transmission of an azimuth burst pulse.SOLUTION: A tactical air navigation ground device has: a pulse generation circuit which generates a pulse gate of a transmission pulse; a modulation part which modulates an RF signal into the transmission pulse in timing of the pulse gate of the transmission pulse generated by a pulse generation part; a power amplifier which amplifies the transmission pulse modulated by the modulation part by an RF power transistor to be transmitted to an antenna; and a squitter compensation pulse generation circuit which generates a trigger of a squitter compensation pulse at preset time intervals in a fixed period until junction temperature of the RF power transistor is stabilized after termination of the trigger of the azimuth burst pulse generated as the transmission pulse by the pulse generation part. The pulse generation circuit generates the pulse gate of the transmission pulse in priority in order of the azimuth burst pulse, a station identification signal pulse, the squitter compensation pulse, a response pulse, and the squitter pulse.

Description

  The present invention relates to a TACAN (TACtical Air Navigation) ground device.

  The Takan device is composed of a Takan on-board device mounted on an aircraft and a Takan ground device installed on the ground.

  The Takan on-board device transmits an interrogation pulse to the Takan ground device, receives a response pulse for the interrogation pulse from the Takan ground device, and based on the time difference between the transmission of the interrogation pulse and the reception of the response pulse, Calculate the distance to the Takan ground equipment.

  In addition, the on-air unit on the Takan aircraft always receives azimuth information transmitted from the Takan ground device (a signal that is amplitude-modulated at the antenna with all transmission pulse signals transmitted from the Takan ground device as a Takan transmission output signal). Based on the received signal, its own direction is calculated.

  FIG. 3 shows a configuration example of a related Takan ground device.

  As shown in FIG. 3, the related Takan ground device includes an RF transmitter 1, a modulation unit 2, a power amplifier 3, an antenna 4, a pulse generation circuit 5, a Takan ground receiver 6, and transmission power detection. A circuit 7 and a compensation voltage generation circuit 8 are included.

  The RF oscillator 1 oscillates a CW (Continuous Wave) RF (Radio Frequency) signal that is a source of a Takan transmission output signal.

  The modulation unit 2 modulates the CW RF signal oscillated by the RF oscillator 1 into a Gaussian pulse (transmission pulse) at the timing of the pulse gate generated by the pulse generation circuit 5.

  Further, the modulation unit 2 corrects the peak value of the transmission power of the modulated Gaussian pulse based on the compensation voltage generated by the compensation voltage generation circuit 8.

  The power amplifier 3 amplifies the Gaussian pulse modulated by the modulation unit 2 to a predetermined transmission power with an RF power transistor (not shown), and radiates it as a takan transmission output signal from the antenna 4 toward the apparatus on the takan machine. To do.

  The transmission power detection circuit 7 detects the peak value of the transmission power of the Takan transmission output signal radiated to the antenna 4 by the power amplifier 3.

  The compensation voltage generation circuit 8 generates a compensation voltage for correcting the peak value of the transmission power of the Takan transmission output signal detected by the transmission power detection circuit 7 to a constant value, and outputs the compensation voltage to the modulation unit 2. Feedback control is performed. The compensation voltage is generated by averaging the transmission power of the Takan transmission output signal.

  Upon receiving the interrogation pulse from the on-aircraft device 4 via the antenna 4, the takan ground receiver 6 decodes the received interrogation pulse and generates a response pulse trigger based on the decoded information. To do.

  The pulse generation circuit 5 generates a pulse gate of an azimuth burst pulse, a station identification signal pulse, and a random squitter pulse as a reference of azimuth information, and also based on a response pulse trigger generated by the Takan ground receiver 6. The pulse gate of the response pulse is generated.

  The pulse generation circuit 5 generates pulse gates in the order of priority in the order of azimuth burst pulse, station identification signal pulse, response pulse, and random squitter pulse. The timing of the pulse gate becomes the transmission timing of the Takan transmission output signal.

  The Takan airborne device includes a bearing burst pulse (north reference signal, coarse bearing reference signal) transmitted from the Takan ground device, and bearing information transmitted from the Takan ground device (a signal amplitude-modulated to 15 Hz and 135 Hz in the antenna 4). ) And calculate its own direction.

  As an example of the azimuth burst pulse, in the X mode, the north reference signal is composed of 12 pair pulses having a pulse width of 3.5 μS which are 12 μs apart from each other, and the coarse reference signal is composed of 6 pair pulses. . The time interval between these pair pulses is 24 μS for the former and 30 μS for the latter. Further, the duty of the azimuth burst pulse is about 10 times that of the random squitter pulse.

JP-A-9-127226

  The operation of the related Takan ground apparatus shown in FIG. 3 will be described below with reference to FIG.

  4A shows the transmission power waveform when the transmission power of the Takan transmission output signal is not controlled by the compensation voltage, and FIG. 4B shows the transistor junction temperature of the RF power transistor of the power amplifier 3. (C) shows the compensation voltage, and (d) shows the transmission power waveform when the transmission power of the Takan transmission output signal is controlled by the compensation voltage.

  As shown in FIG. 4B, the transistor junction temperature rapidly rises during transmission of the azimuth burst pulse.

  Therefore, when the transmission power of the Takan transmission output signal is not controlled by the compensation voltage, the peak value of the transmission power decreases as the transistor junction temperature increases due to the transmission of the azimuth burst pulse, as shown in FIG. .

  Therefore, as shown in FIG. 4C, a compensation voltage having a characteristic opposite to the transmission power is applied to the transistor (not shown) of the modulation unit 2 with respect to the increase in the transistor junction temperature due to the transmission of the azimuth burst pulse. .

  Thereby, as shown in FIG.4 (d), the fall of the peak value of the transmission power during transmission of an azimuth | direction burst pulse is suppressed.

  Further, as shown in FIG. 4D, 80 μS after transmission of the azimuth burst pulse is a period during which transmission is not performed.

  For this reason, a transmission pulse (response pulse or squitter pulse) is generated after the lapse of the above period. The transmission pulse is generated at the timing of the interrogation pulse from the on-machine device or the timing of the squitter pulse. Because of this, the timing is random.

  In the Takan ground apparatus, it is necessary to continuously transmit the direction information even after transmitting the direction burst pulse. For this reason, the transmission pulse generated after the transmission of the azimuth burst pulse is transmitted within a period until the transistor junction temperature suddenly increases due to the transmission of the azimuth burst pulse and then decreases and stabilizes.

  However, the related Takan ground device has a problem that the correction of the peak value of the transmission power by the compensation voltage is unstable during the period until the transistor junction temperature is stabilized after the transmission of the azimuth burst pulse.

  Hereinafter, this problem will be described in detail.

  As shown in FIG. 4A, the generation timing of the transmission pulse after transmission of the azimuth burst pulse is roughly divided into a transmission pulse generation timing (1) having a coarse pulse width and a transmission pulse generation timing (1) having a narrow pulse width. 2).

  As shown in FIG. 4B, the transistor junction temperature is stabilized under the conditions of the transmission pulse generation timing (1) with a narrow pulse width and the transmission pulse generation timing (2) with a narrow pulse interval. Thermal fluctuations exhibit different characteristics.

  When the conditions of the transmission pulse generation timing (1) and the conditions of the transmission pulse generation timing (2) are compared, the condition of the transmission pulse generation timing (2) with a narrow pulse width is until the transistor junction temperature is stabilized. Thermal fluctuations are irregular.

  Therefore, as shown in FIG. 4C, while the compensation voltage is decreased, the transistor junction temperature is irregularly changed as shown in FIG. 4B. Therefore, depending on the change of the transistor junction temperature. The correction of the transmission power by the compensation voltage does not work normally, and the peak value of the transmission power may become unstable.

  For example, as shown in FIG. 4D, transmission power correction works normally under the condition of transmission pulse generation timing (1), and transmission power correction is normal under the condition of transmission pulse generation timing (2). An event that does not affect

  In the Takan airborne device, the azimuth is calculated based on the power peak value of the signal transmitted from the Takan ground device and amplitude-modulated in the antenna. The result was unstable.

  Therefore, an object of the present invention is to provide a Takan ground device that can stabilize the peak value of transmission power.

The Takan ground device of the present invention is
A pulse generation circuit for generating a pulse gate of a transmission pulse;
A modulation unit that modulates an RF signal into a transmission pulse at the timing of a pulse gate of the transmission pulse generated by the pulse generation unit;
A power amplifier for amplifying the transmission pulse modulated by the modulation unit with an RF power transistor and transmitting the amplified pulse to an antenna;
After the trigger of the azimuth burst pulse generated as a transmission pulse by the pulse generator, the squitter compensation pulse is triggered at predetermined time intervals until the junction temperature of the RF power transistor is stabilized. A squitter compensation pulse generation circuit for generating,
The pulse generating circuit generates a pulse gate of a transmission pulse in the order of priority of an azimuth burst pulse, a station identification signal pulse, a squitter compensation pulse, a response pulse, and a squitter pulse.

  According to the Takan ground apparatus of the present invention, the transmission power peak value is stabilized because the squitter compensation pulse is transmitted at a preset time interval after the transmission of the azimuth burst pulse until the transistor junction temperature is stabilized. The effect that it can aim at is acquired.

It is a block diagram which shows one structural example of the Takan ground apparatus of one Embodiment of this invention. It is a figure explaining operation | movement of the Takan ground apparatus shown in FIG. It is a block diagram which shows one structural example of the related Takan ground apparatus. It is a figure explaining operation | movement of the Takan ground apparatus shown in FIG.

  Hereinafter, an embodiment of a Takan ground apparatus according to the present invention will be described with reference to the drawings.

  In FIG. 1, the structure of the Takan ground apparatus of one Embodiment of this invention is shown.

  As shown in FIG. 1, the Takan ground apparatus of this embodiment is different from FIG. 3 in that a squitter compensation pulse generation circuit 9 is provided.

  Hereinafter, a different part from FIG. 3 is demonstrated.

  The squitter compensation pulse generation circuit 9 receives a pulse gate of the azimuth burst pulse from the pulse generation circuit 5, and after the trigger of the azimuth burst pulse ends, a certain time (for example, 80 μS, see FIGS. 2 and 4) has elapsed. From this time, a trigger for a squitter compensation pulse is generated at a preset time interval and output to the pulse generation circuit 5 during a certain period until the transistor junction temperature becomes stable.

  For the squitter compensation pulse generation circuit 9, in order to realize the above-described operation, a period length until the transistor junction temperature is stabilized after the transmission of the azimuth burst pulse (after the trigger of the azimuth burst pulse is finished) is set in advance. Estimate and set the estimated period length.

  The pulse generation circuit 5 generates a pulse gate of an azimuth burst pulse, a station identification signal pulse, and a random squitter pulse as a reference of azimuth information, and also based on a response pulse trigger generated by the Takan ground receiver 6. In addition, a pulse gate of the response pulse is generated, and a squitter compensation pulse is generated based on the trigger of the squitter compensation pulse generated by the squitter compensation pulse generation circuit 9.

  The pulse generation circuit 5 generates pulse gates in the order of priority in the order of azimuth burst pulse, station identification signal pulse, squitter compensation pulse, response pulse, and random squitter pulse. Therefore, after the transmission of the azimuth burst pulse, the pulse gate of the response pulse or the random squitter pulse is suppressed for the certain period, and only the pulse gate of the squitter compensation pulse is generated. After the elapse of the predetermined period, a pulse gate of a response pulse or a random squitter pulse is generated.

  The operation of the Takan ground apparatus according to the present embodiment shown in FIG. 1 will be described below with reference to FIG.

  2, (e) shows the transmission power waveform when the transmission power of the Takan transmission output signal is not controlled by the compensation voltage, and (f) shows the transistor junction temperature of the RF power transistor of the power amplifier 3. (G) shows the compensation voltage, and (h) shows the transmission power waveform when the transmission power of the Takan transmission output signal is controlled by the compensation voltage.

  As shown in FIG. 2E, in this embodiment, the squitter compensation pulse generation circuit 9 causes the squitter compensation pulse generation circuit 9 to transmit the azimuth burst pulse until the transistor junction temperature becomes stable at a preset time interval. Send.

  In the Takan ground device, in order to continuously transmit the azimuth information, a transmission pulse is necessary until the transistor junction temperature is stabilized.

  Since the squitter compensation pulse has a preset time interval, the peak value of the transmission power can be accurately corrected by the compensation voltage as shown in FIG.

  Therefore, it is possible to transmit a transmission pulse with stable transmission power from the Takan ground device even during a period until the transistor junction temperature is stabilized.

  Note that the squitter pulse or the response pulse is transmitted after the transistor junction temperature is stabilized.

  As described above, in the related Takan ground device, after transmitting the azimuth burst pulse, the squitter pulse or the response pulse is transmitted at random timing during the period until the transistor junction temperature is stabilized. For this reason, there has been a problem that correction of transmission power by feedback control becomes unstable.

  On the other hand, in the Takan ground device according to the present embodiment, after transmitting the azimuth burst pulse, the squitter compensation pulse is transmitted at a preset time interval during the period until the transistor junction temperature becomes stable. The power correction can be stabilized, whereby the peak value of the transmission power can be stabilized.

  Further, the Takan on-board device calculates the azimuth based on the signal transmitted from the Takan ground device and amplitude-modulated at the antenna, so that the peak value of the transmission power is stabilized and calculated by the Takan on-board device. The direction can be stabilized.

DESCRIPTION OF SYMBOLS 1 RF oscillator 2 Modulation part 3 Power amplifier 4 Antenna 5 Pulse generation circuit 6 Takan ground receiver 7 Transmission power detection circuit 8 Compensation voltage generation circuit 9 Squitter compensation pulse generation circuit

Claims (2)

A pulse generation circuit for generating a pulse gate of a transmission pulse;
A modulation unit that modulates an RF signal into a transmission pulse at the timing of a pulse gate of the transmission pulse generated by the pulse generation unit;
A power amplifier for amplifying the transmission pulse modulated by the modulation unit with an RF power transistor and transmitting the amplified pulse to an antenna;
After the trigger of the azimuth burst pulse generated as a transmission pulse by the pulse generator, the squitter compensation pulse is triggered at predetermined time intervals until the junction temperature of the RF power transistor is stabilized. A squitter compensation pulse generation circuit for generating,
The Takan ground apparatus, wherein the pulse generation circuit generates a pulse gate of a transmission pulse in the order of priority of an azimuth burst pulse, a station identification signal pulse, a squitter compensation pulse, a response pulse, and a squitter pulse.   2. The Takan ground apparatus according to claim 1, wherein the pulse generation circuit generates a pulse gate of a response pulse or a squitter pulse after the fixed period has elapsed.

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