阅读说明：本技术 一种飞机机载dme测距设备 (Airborne DME (dimethyl ether) distance measuring equipment of airplane ) 是由 赵晶晶 王新芳 杨晓旭 高健雄 王健 于 2019-10-30 设计创作，主要内容包括：本发明提出了一种飞机机载DME测距设备,包括DME测距仪,所述DME测距仪包括CPU、频率合成器、发射机、接收机、环流器、天线、反馈电路、自动增益控制电路、抗干扰电路,所述CPU与所述频率合成器、自动增益控制电路连接,所述频率合成器分别与发射机、接收机连接,所述发射机与环流器连接,所述自动增益控制电路与所述反馈电路连接,所述反馈电路与所述接收机连接,所述天线与抗干扰电路连接,所述抗干扰电路与所述环流器连接,所述环流器与所述接收机连接；本发明还设置了反馈电路、自动增益控制电路、抗干扰电路,利用反馈电路和自动增益控制电路来调节接收机增益的大小,从而减小测距误差,降低多路径干扰。(The invention provides airborne DME (dimethyl ether) distance measuring equipment of an airplane, which comprises a DME distance measuring instrument, wherein the DME distance measuring instrument comprises a CPU (Central processing Unit), a frequency synthesizer, a transmitter, a receiver, a circulator, an antenna, a feedback circuit, an automatic gain control circuit and an anti-interference circuit, the CPU is connected with the frequency synthesizer and the automatic gain control circuit, the frequency synthesizer is respectively connected with the transmitter and the receiver, the transmitter is connected with the circulator, the automatic gain control circuit is connected with the feedback circuit, the feedback circuit is connected with the receiver, the antenna is connected with the anti-interference circuit, the anti-interference circuit is connected with the circulator, and the circulator is connected with the receiver; the invention also arranges a feedback circuit, an automatic gain control circuit and an anti-interference circuit, and utilizes the feedback circuit and the automatic gain control circuit to adjust the gain of the receiver, thereby reducing the ranging error and reducing the multipath interference.)

1. An airborne DME distance measuring device of an airplane comprises a DME distance measuring device, wherein the DME distance measuring device comprises a CPU, a frequency synthesizer, a transmitter, a receiver, a circulator and an antenna, and is characterized by further comprising a feedback circuit, an automatic gain control circuit and an anti-interference circuit, wherein the CPU is connected with the frequency synthesizer and the automatic gain control circuit, the frequency synthesizer is respectively connected with the transmitter and the receiver, the transmitter is connected with the circulator, the automatic gain control circuit is connected with the feedback circuit, the feedback circuit is connected with the receiver, the antenna is connected with the anti-interference circuit, the anti-interference circuit is connected with the circulator, and the circulator is connected with the receiver;

the feedback circuit comprises a feedback amplifier, a first grounding resistor and a first resistor, wherein the input end of the feedback amplifier is connected with the transmitter through the first resistor, the other input end of the feedback amplifier is connected with the output end of the automatic gain control circuit, the other input end of the feedback amplifier is also connected with the first grounding resistor, and the output end of the feedback amplifier is connected with the receiver;

the automatic gain control circuit comprises a gain amplifier, wherein the input end of the gain amplifier is connected with the CPU, and the output end of the gain amplifier is connected with the feedback amplifier.

2. The DME ranging apparatus as claimed in claim 1, wherein the automatic gain control circuit further comprises a gain adjustment circuit, the gain adjustment circuit comprises a first secondary winding, a second secondary winding, a first transistor, a second resistor, a sixth resistor, a first capacitor, a third capacitor, a first output of the first secondary winding is connected to one end of the second resistor, a second output of the first secondary winding is connected to one end of the first capacitor, one end of the third resistor, and one end of the fourth resistor, another end of the second resistor is connected to the base of the first transistor, a collector of the first transistor is connected to a collector of the second transistor, one end of the fifth resistor, one end of the second capacitor, and one input end of the second secondary winding, and another input end of the second secondary winding is connected to the other end of the second capacitor, The emitter of the first transistor is connected with the base of the second transistor, and the emitter of the second transistor is connected with one end of the sixth resistor and one end of the third capacitor.

3. An aircraft onboard DME ranging apparatus as in claim 2 wherein the other end of said first capacitor is connected to the other end of said third resistor and both are connected to ground.

4. An aircraft onboard DME ranging device according to claim 1, wherein the other input end of the gain amplifier is further connected with one end of a seventh resistor and one end of an eighth resistor, the other end of the seventh resistor is connected with the input interface, the other end of the eighth resistor is connected with one end of a sixth resistor and the anode of a diode, and the cathode of the diode is grounded.

5. A DME ranging apparatus onboard an aircraft as in claim 1, wherein the input of said feedback amplifier is further connected to the output of said feedback amplifier through a ninth resistor.

6. An aircraft onboard DME ranging device according to claim 1, wherein the anti-jamming circuit comprises a coupler, an inductor, a tenth resistor, a fourth capacitor and a third transistor, wherein an output of the coupler is connected with one end of the tenth resistor, the other end of the tenth resistor is connected with one end of the inductor, the other end of the inductor is connected with one end of the fourth capacitor, a collector electrode of the third transistor and the other end of the fourth capacitor is connected with the antenna.

7. An aircraft onboard DME ranging device as claimed in claim 6 wherein the emitter of the third transistor is connected to ground.

8. An aircraft onboard DME ranging apparatus as claimed in claim 6 wherein one end of said inductor is further connected to a supply voltage.

9. An aircraft-onboard DME ranging apparatus as in claim 1 wherein said feedback amplifier is of the type THS 3201.

10. An aircraft-onboard DME ranging apparatus as in claim 1 wherein said gain amplifier is of VCA824 type.

Technical Field

The invention relates to the technical field of distance measuring instruments, in particular to airborne DME distance measuring equipment for an airplane.

Background

The rangefinder (DME) is also known as a pulsed short range navigation system. The Doppler omnidirectional beacon is used for providing linear distance information between an airplane and a ground platform, is often installed on one side of a runway together with a Doppler omnidirectional beacon at an airport, shares the same station, determines the accurate position of the airplane by combining azimuth information given by the omnidirectional beacon, provides medium-short range navigation information for the airplane, and ensures the safe landing of the airplane by matching with an instrument landing system.

The distance measurement is that the airborne receiver sends out an inquiry pulse, the ground station of the range finder sends out a response pulse containing coded information after receiving the inquiry pulse through a fixed time delay, and the airborne receiver calculates the linear distance information relative to the ground station through the time interval between the sending and receiving of the pulse after receiving the response pulse. When the aircraft enters a port according to the navigation information and is ready to land, the flying height is gradually reduced, objects such as mountains, houses, large parked aircraft and the like around the airport can cause multipath interference, the pulse waveform sent by the distance meter is influenced, and the distortion of the pulse waveform can cause the deviation of the interval time measured by the airborne receiver. Through practical operation experience, multipath interference is the most main reason for influencing DME ranging accuracy. In addition, some other factors may also cause the ranging error, such as unstable fixed delay given by the device, unfixed amplitude of the signal received by the transponder, etc.

Disclosure of Invention

The object of the present invention is to solve at least one of the technical drawbacks mentioned.

Therefore, the invention aims to provide an onboard DME (dimethyl ether) distance measuring device for an airplane, which can reduce multipath interference.

In order to achieve the purpose, the invention provides airplane airborne DME distance measuring equipment which comprises a DME distance measuring instrument, wherein the DME distance measuring instrument comprises a CPU, a frequency synthesizer, a transmitter, a receiver, a feedback circuit, a circulator, an antenna, a feedback circuit, an automatic gain control circuit and an anti-interference circuit, the CPU is connected with the frequency synthesizer and the automatic gain control circuit, the frequency synthesizer is respectively connected with the transmitter and the receiver, the transmitter is connected with the circulator, the automatic gain control circuit is connected with the feedback circuit, the feedback circuit is connected with the receiver, the antenna is connected with the anti-interference circuit, the anti-interference circuit is connected with the circulator, and the circulator is connected with the receiver;

the feedback circuit comprises a feedback amplifier, a first grounding resistor and a first resistor, wherein the input end of the feedback amplifier is connected with the transmitter through the first resistor, the other input end of the feedback amplifier is connected with the output end of the automatic gain control circuit, the other input end of the feedback amplifier is also connected with the first grounding resistor, and the output end of the feedback amplifier is connected with the receiver;

the automatic gain control circuit comprises a gain amplifier, wherein the input end of the gain amplifier is connected with the CPU, and the output end of the gain amplifier is connected with the feedback amplifier.

In any of the foregoing schemes, preferably, the automatic gain control circuit further includes a gain adjustment circuit, the gain adjustment circuit includes a first secondary winding, a second secondary winding, a first transistor, a second resistor, a sixth resistor, and a first capacitor, a third capacitor, a first output of the first secondary winding is connected to one end of the second resistor, a second output of the first secondary winding is connected to one end of the first capacitor, one end of the third resistor, and one end of the fourth resistor, another end of the second resistor is connected to a base of the first transistor, a collector of the first transistor is connected to a collector of the second transistor, one end of the fifth resistor, one end of the second capacitor, and one input end of the second secondary winding, another input end of the second secondary winding is connected to another end of the second capacitor, another end of the fifth resistor, and a voltage regulator, And the emitter of the first transistor is connected with the base of the second transistor, and the emitter of the second transistor is connected with one end of the sixth resistor and one end of the third capacitor.

In any of the above schemes, preferably, the other end of the first capacitor is connected to the other end of the third resistor and both ends are grounded.

In any of the above schemes, preferably, another input terminal of the gain amplifier is further connected to one end of a seventh resistor and one end of an eighth resistor, another end of the seventh resistor is connected to the input interface, another end of the eighth resistor is connected to one end of the sixth resistor and an anode of the diode, and a cathode of the diode is grounded.

In any of the above schemes, preferably, the input terminal of the feedback amplifier is further connected to the output terminal of the feedback amplifier through a ninth resistor.

In any of the above schemes, preferably, the interference rejection circuit includes a coupler, an inductor, a tenth resistor, a fourth capacitor, and a third transistor, an output of the coupler is connected to one end of the tenth resistor, another end of the tenth resistor is connected to one end of the inductor, another end of the inductor is connected to one end of the fourth capacitor, a collector of the third transistor, and another end of the fourth capacitor is connected to the antenna.

In any of the above aspects, it is preferable that an emitter of the third transistor is grounded.

In any of the above schemes, preferably, one end of the inductor is further connected to a power supply voltage.

In any of the above schemes, it is preferable that the feedback amplifier is in the type of THS 3201.

In any of the above schemes, the type of the gain amplifier is preferably VCA 824.

The airplane airborne DME distance measuring equipment has the following beneficial effects:

1. the invention also arranges a feedback circuit, an automatic gain control circuit and an anti-interference circuit, and utilizes the feedback circuit and the automatic gain control circuit to adjust the gain of the receiver, thereby reducing the ranging error and reducing the multipath interference.

2. The invention combines the automatic gain control circuit with the feedback circuit, so that when the input signal changes greatly, the output signal of the receiver is kept basically stable, namely when the input signal is weak, the gain of the receiver is high; when the input signal is strong, the receiver gain is low.

3. Because the gain of the amplifier is closely related to the load, the gain adjusting circuit is arranged to change the load of the feedback amplifier, part of the load of the feedback amplifier is output by the joint action of the first transistor and the second transistor in the gain adjusting circuit, and the part of the load of the feedback amplifier is changed by controlling the conduction condition of the first transistor and the second transistor, thereby achieving the purpose of controlling the gain of the amplifier.

4. The input interface in the automatic gain control circuit of the invention can also be connected with the CPU, and the CPU adjusts the signal output by the gain amplifier, thereby adjusting the gain of the receiver.

5. The invention adopts the design of combining the coupler and the inductor, and can further improve the anti-interference capability of the antenna.

6. The automatic gain control circuit and the feedback circuit have simple circuit structures, relatively few components and low manufacturing cost, and can be popularized and used in a large range.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a circuit schematic of the feedback circuit of the present invention;

FIG. 3 is a circuit schematic of the gain adjustment circuit of the present invention:

FIG. 4 is a schematic circuit diagram of the immunity circuit of the present invention

In the figure, 1, CPU; 2. a frequency synthesizer; 3. a transmitter; 4. a receiver; 5. a feedback circuit; 6. an automatic gain control circuit; 7. a circulator; 8. an anti-jamming circuit; 9. an antenna;

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

DME (distance measuring device) is a signal generator of radio navigation equipment used by aircraft, installed on airports and on the air routes, and is the main air route navigation equipment. The aircraft uses the DME to measure its distance to the ground transmitter by transmitting a signal that receives a pair of pulses at fixed intervals.

The invention provides airplane airborne DME distance measuring equipment, which comprises a DME distance measuring instrument, wherein the DME distance measuring instrument comprises a CPU1, a frequency synthesizer 2, a transmitter 3, a receiver 4, a circulator 7 and an antenna 9, on the basis, the DME distance measuring instrument is further provided with a feedback circuit 5, an automatic gain control circuit 6 and an anti-interference circuit 8, the CPU1 is connected with the frequency synthesizer 2 and the automatic gain control circuit 6, the frequency synthesizer 2 is respectively connected with the transmitter 3 and the receiver 4, the transmitter 3 is connected with the circulator 7, the automatic gain control circuit 6 is connected with the feedback circuit 5, the feedback circuit 5 is connected with the receiver 4, the antenna 9 is connected with the anti-interference circuit 8, the anti-interference circuit 8 is connected with the circulator 7, and the circulator 7 is connected with the receiver 4.

Where the CPU1 uses the tuning input to tune the frequency synthesiser 2 and the frequency synthesiser 2 supplies the frequency of the pulses to the transmitter, when the airborne DME ranging apparatus transmits a pulsed signal to the ground, the CPU1 supplies a signal to the transmitter 3 to transmit an interrogation pulse which passes through a circulator 7 to an antenna 9 and then transmits the pulsed signal via the antenna 9. The antenna 9 can also receive signals transmitted by the ground transmitter, and after passing through the circulator 7, the pulse signals are output to the receiver 4, and the receiver 4 outputs the signals to the CPU 1.

The DME range finder ranging error is also related to the distance it measures, since the magnitude of the radiated power, the magnitude of the receiver gain directly affect the crossing time of the decision threshold level and the rising edge of the pulse, and due to their variations, the magnitude of the ranging accuracy can be directly affected. Therefore, the invention is also provided with a feedback circuit 5, an automatic gain control circuit 6 and an anti-jamming circuit 8, and the feedback circuit 5 and the automatic gain control circuit 6 are utilized to adjust the gain of the receiver, thereby reducing the distance measurement error.

The principle of the invention in automatic gain adjustment is as follows: the automatic gain control circuit transmits the input quantity to the feedback circuit, the feedback circuit compares the input quantity with the comparison quantity, and when deviation occurs, a correction quantity is generated to adjust the output quantity.

As shown in fig. 2, the feedback circuit 5 includes a feedback amplifier U21, a first ground resistor R7, and a first resistor R5, an input terminal of the feedback amplifier U21 is connected to the transmitter 3 through the first resistor R5, another input terminal of the feedback amplifier U21 is connected to an output terminal of the automatic gain control circuit 6, another input terminal of the feedback amplifier U21 is further connected to the first ground resistor R7, and an output terminal of the feedback amplifier U21 is connected to the receiver 4; the input terminal of the feedback amplifier U21 is further connected to the output terminal of the feedback amplifier U21 through a ninth resistor R3, wherein the ninth resistor R3 is a feedback resistor. Preferably, the feedback amplifier is selected from the THS3201 model.

The invention is provided with a first grounding resistor R7, a first resistor R5 and a ninth resistor R3, and can set the relationship among the input quantity, the comparison quantity, the output quantity and the correction quantity of the feedback amplifier U21 according to the resistance value of the resistors.

The present invention uses automatic gain control circuit 6 in conjunction with a feedback circuit to keep the output signal of the receiver substantially stable when the input signal varies widely, i.e., when the input signal is weak, the receiver gain is high; when the input signal is strong, the receiver gain is low.

The automatic gain control circuit 6 includes a gain amplifier U22, an input terminal of the gain amplifier U22 is connected to the CPU1, and an output terminal of the gain amplifier U22 is connected to the feedback amplifier U21. The other input end of the gain amplifier U22 is further connected to one end of a seventh resistor RDA1 and one end of an eighth resistor RDA2, the other end of the seventh resistor RDA1 is connected to the input interface DA1, the other end of the eighth resistor RDA2 is connected to one end of a sixth resistor RDA3 and the anode of the diode DDA1, and the cathode of the diode DDA1 is grounded. The input interface DA1 may also be connected to the CPU1, and the CPU1 may adjust the signal output by the gain amplifier U22, thereby adjusting the gain of the receiver. Preferably, the gain amplifier is of the type selected from VCA 824. The circuit provides conversion from differential input to single-ended without external buffering, and the flexibility of design is improved by changing the resistance value of an external resistor to increase variation.

In addition, the automatic gain control circuit 6 is also connected with the CPU1 and the receiver 4, and can output an AGC voltage which automatically changes along with the change of the output voltage of the CPU1 to the feedback circuit according to the change of the output voltage of the CPU1, and control the gain of some stages of the receiver by using the AGC voltage, thereby achieving the purpose of automatic gain.

As shown in fig. 3, the automatic gain control circuit 6 further includes a gain adjustment circuit, the gain adjustment circuit includes a first secondary winding TR1, a second secondary winding TR2, a first transistor Q11, a second transistor Q12, a second resistor R72-a sixth resistor R76, a first capacitor C71-a third capacitor C73, a first output of the first secondary winding TR1 is connected to one end of the second resistor R72, a second output of the first secondary winding TR1 is connected to one end of the first capacitor C71, one end of the third resistor R73, one end of the fourth resistor R74, another end of the second resistor R72 is connected to a base of the first transistor Q11, a collector of the first transistor Q11 is connected to a collector of the second transistor Q12, one end of the fifth resistor R75, one end of the second capacitor C72, one input end of the second secondary winding TR2, another input of the second secondary winding TR 56 is connected to the other end of the second capacitor C5953, another end of the second capacitor R8427, and another end of the second resistor R8653, The other end of the fourth resistor R74, the emitter of the first transistor Q11 is connected to the base of the second transistor Q12, and the emitter of the second transistor Q12 is connected to one end of the sixth resistor R76 and one end of the third capacitor C73. The other end of the first capacitor C71 is connected to the other end of the third resistor R73 and both ends are grounded.

Since the gain of the feedback amplifier is closely related to the load, the present invention provides a gain adjustment circuit to change the load of the feedback amplifier U21, a part of the load of the feedback amplifier U21 is jointly acted by the first transistor Q11 and the second transistor Q12 in the gain adjustment circuit to output, and the part of the load of the feedback amplifier U21 is changed by controlling the conduction conditions of the first transistor Q11 and the second transistor Q12, specifically, when the voltage of the output signal of the gain amplifier U22 meets the conduction conditions of the first transistor Q11 and the second transistor Q12, the first transistor Q11 and the second transistor Q12 are turned on, and the equivalent resistance of the automatic gain control circuit 6 is changed, that is, the value of the part of the load of the feedback amplifier U21 is changed, thereby achieving the purpose of controlling the gain of the amplifier.

In addition, in order to improve the anti-interference capability of the antenna, an anti-interference circuit is arranged, as shown in fig. 4.

The anti-interference circuit 8 comprises a coupler U30, an inductor L5, a tenth resistor R61, a fourth capacitor C63 and a third transistor Q7, wherein the output end of the coupler U30 is connected with one end of the tenth resistor R61, the other end of the tenth resistor R61 is connected with one end of the inductor L5, the other end of the inductor L5 is connected with one end of the fourth capacitor C63 and the collector of the third transistor Q7, and the other end of the fourth capacitor C63 is connected with an antenna E1. The emitter of the third transistor Q7 is grounded. One end of the inductor L5 is also connected to the power supply voltage.

The design of combining the coupler U30 and the inductor L5 is adopted, so that the anti-interference capability of the antenna can be further improved.

In summary, when the pulse signal changes, the feedback circuit and the automatic gain control circuit are used to automatically adjust the gain of the receiver, so as to ensure the stability of the pulse signal, reduce the multipath interference, and reduce the ranging error.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.