Continuously adjustable radio altimeter detector

Abstract

The invention discloses a continuously adjustable radio altimeter detector, which comprises a control assembly, an optical transmitter, an optical receiver, a time delay module, a radio frequency amplifier and a power attenuation module, and is characterized in that an electric signal of a radio altimeter enters the optical transmitter, then is converted into an optical signal and enters the time delay module; the delay module receives a delay control signal output by the control assembly, determines delay time of an optical signal, realizes different time delays of the optical signal by combining on-off of different optical switches and mechanical delay, and the delayed optical signal enters an optical receiver and then is converted into an electric signal, and the electric signal is amplified by a radio frequency amplifier; and the power attenuation module is used for carrying out attenuation of different power level values on the amplified electric signal according to an attenuation control signal provided by the control assembly, outputting a power attenuation signal and sending the power attenuation signal to the wireless altimeter.

Description

Technical Field

[0001] The present invention belongs to the field of aviation manufacturing technology (aircraft function test and detection), and relates to a continuously adjustable radio altimeter altitude simulation device. Specifically, it is a device that can simulate continuously adjustable arbitrary altitude signals with high precision within a certain range. Background Art

[0002] To ensure the normal operation of the aircraft's radio altimeter, a radio altimeter tester is required to test the finished product during installation to determine whether it is operating normally based on performance indicators. When troubleshooting the radio altimeter in the field, it must be disassembled and sent to a laboratory or manufacturer for testing.

[0003] The radio altimeter detector consists of a delay module, a control / display module and a power supply. Figure 1 As shown in the figure, the transceiver sends a signal to the delay module through the transmitting cable. After the signal passes through the delay module, it simulates different altitudes and the power of the RF signal at the corresponding altitudes. Finally, it is sent back to the transceiver through the receiving cable, thereby simulating different altitudes of the aircraft during flight. The control / display module is responsible for setting different parameters in the delay module corresponding to different altitudes. The power module is a 28V external power supply.

[0004] Among them, the delay module is the core module of the radio altimeter detector, and the core of the delay module is to design precise delay lines to simulate the time delays corresponding to different altitudes. At present, the delay module uses surface acoustic wave delay lines, coaxial cable lines and optical fiber delay lines as signal delay lines. However, these delay modules are restricted by conditions such as cost, quality or environmental adaptability. More importantly, the delay module of the current radio altimeter detector can simulate fewer altitude nodes, making it impossible to conduct further performance verification when testing the finished product before installation. Moreover, when the radio altimeter fails and needs to be re-inspected, due to the limited altitude nodes that can be simulated, it is impossible to accurately detect the fault point and it needs to be returned to the factory, wasting a lot of manpower and material resources. Summary of the invention

[0005] The present invention provides a continuously adjustable radio altimeter detector, which solves the problem that the current radio altimeter detector has limited simulated altitude nodes and the altitude simulation cannot be continuously adjusted, resulting in the inability to perform more comprehensive performance testing and troubleshooting on the wireless altimeter.

[0006] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0007] A continuously adjustable radio altimeter detector includes a control component, an optical transmitter, an optical receiver, a delay module, a radio frequency amplifier, and a power attenuation module, wherein:

[0008] The input end of the optical transmitter is connected to the electrical signal of the radio altimeter, the output end of the optical transmitter is connected to the input end of the delay module, the output end of the delay module is connected to the input end of the optical receiver, the output end of the optical receiver is connected to the input end of the radio frequency amplifier, and the output end of the frequency amplifier is connected to the input end of the power attenuator; the electrical signal of the radio altimeter enters the optical transmitter and is converted into an optical signal and then enters the delay module, the delay module receives the delay control signal output by the control component, determines the delay time of the optical signal, and uses different optical switch on and off combinations with mechanical delays to achieve different time delays for the optical signal, the delayed optical signal enters the optical receiver and is converted into an electrical signal, and the signal is amplified by the radio frequency amplifier; the power attenuation module is used to attenuate the amplified electrical signal with different power level values ​​according to the attenuation control signal provided by the control component, output a power attenuation signal, and send it to the wireless altimeter.

[0009] Furthermore, the delay module includes multiple optical switches and multiple delay lines. The optical switches are arranged at intervals on the optical path, and each adjacent optical switch is connected by a different delay line. When all the optical switches are closed, the optical signal passes through the optical switch and the optical path normally without delay. When a certain optical switch is turned on, the optical signal passing through the optical switch will enter the delay line for delay before reaching the next optical switch. Through the combination of delay lines of different lengths and different optical switches, the coarse delay of the optical signal at different times is achieved, thereby corresponding to different height signal simulations.

[0010] Furthermore, the delay line uses a G.652 type optical fiber delay line with a wavelength of 1310 nm, a loss of 0.31 dB / m, and a refractive index of 1.4706 of the optical fiber core.

[0011] Furthermore, the delay line lengths corresponding to the simulated heights of 1m, 2m, 3m, 4m, 10m, 20m, 30m, 40m, 100m, 200m, 300m, 400m and 1000m are 1.36m, 2.72m, 4.08m, 5.44m, 13.6m, 27.2m, 40.8m, 54.4m, 136m, 272m, 408m, 544 and 1360m, and the optical switch is a magneto-optical switch.

[0012] Furthermore, the delay control signal and the attenuation control signal of the control component are set according to actual needs.

[0013] Further, the last optical switch of the delay module is connected to the mechanical delay device;

[0014] A stepper motor is installed at one end of the upper surface of the bottom plate of the mechanical delay device, the output shaft of the stepper motor is connected to a lead screw, a guide rail is arranged on the upper surface of the bottom plate, a slidable corner cube prism bracket is installed on the guide rail via a slider, and the corner cube prism is installed on the corner cube prism bracket; the lead screw is threadedly matched with the corner cube prism bracket, the lead screw rotates under the drive of the stepper motor, and drives the corner cube prism bracket to drive the corner cube prism to move on the guide rail; the collimator bracket is installed on the bottom plate, and the last optical switch is connected to the collimator installed on the collimator bracket through an optical fiber, the optical signal output from the output end of the collimator is reflected by the corner cube prism, and after being received by the receiving end of the collimator, the delay caused by the distance difference generated when the optical signal propagates between the collimator and the corner cube prism is used to realize high-precision delay adjustment of the optical signal.

[0015] Furthermore, the bottom of the slider cooperates with the guide rail through a steel ball and a retainer, and a dustproof sheet is provided at the bottom of the steel ball; in order to ensure smooth sliding of the slider, an oil nozzle for providing lubricating oil is provided on the end cover of the slider, and the lubricating oil is applied using an oil scraper.

[0016] Furthermore, the optical receiver adopts a direct detection receiver, and the photodetector in the optical receiver adopts a PIN photodiode which is insensitive to temperature changes and has a fast response speed.

[0017] Compared with the prior art, the present invention has the following technical features:

[0018] 1. Continuously adjustable altitude simulation is achieved at an altitude of 0-2111m, which is very suitable for the scenario of multiple altitude simulations during installation experiments of radio altimeters. When troubleshooting radio altimeters, specific altitude simulations with an accuracy of 0.001m can be performed, solving the problem of limited simulated altitude of aircraft in the field.

[0019] 2. Add a power attenuation module to detect the sensitivity of the radio altimeter transceiver at different simulated altitudes.

[0020] 3. The product design structure is simple, not easily affected by complex electromagnetic environment and other interferences, with high cost performance and strong robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a connection diagram of the radio altimeter detector;

[0022] Figure 2 This is the principle block diagram of the delay module of the radio altimeter detector;

[0023] Figure 3 This is the principle block diagram of the optical transmitter;

[0024] Figure 4 It is a schematic diagram of the delay module-optical fiber combination module;

[0025] Figure 5 This is a schematic diagram of the mechanically adjustable module in the delay module;

[0026] Figure 6 It is a schematic diagram of the corner cube prism structure of the mechanical delay module;

[0027] Figure 7 It is a schematic diagram of the guide rail structure of the mechanical delay module;

[0028] Among them: 1 corner cube prism, 2 corner cube prism bracket, 3 guide rail, 4 oil nozzle, 5 oil scraper, 6 end cover, 7 slider, 8 steel ball, 9 dust cover, 10 holder, 11 collimator, 12 collimator bracket, 13 stepper motor, 14 bottom plate, 15 lead screw, 16 optical fiber. DETAILED DESCRIPTION

[0029] In order to make the purpose and scheme of the present invention clearer, it is further described in conjunction with the drawings and specific examples.

[0030] like Figure 2 As shown, the present invention provides a novel wireless altimeter detector, including a control component, an optical transmitter, an optical receiver, a delay module, a radio frequency amplifier, and a power attenuation module, wherein:

[0031] The input end of the optical transmitter is connected to the electrical signal of the radio altimeter, the output end of the optical transmitter is connected to the input end of the delay module, the output end of the delay module is connected to the input end of the optical receiver, the output end of the optical receiver is connected to the input end of the radio frequency amplifier, and the output end of the frequency amplifier is connected to the input end of the power attenuator; the electrical signal of the radio altimeter enters the optical transmitter and is converted into an optical signal and then enters the delay module, the delay module receives the delay control signal output by the control component, determines the delay time of the optical signal, and uses different optical switch on and off combinations with mechanical delays to achieve different time delays for the optical signal, the delayed optical signal enters the optical receiver and is converted into an electrical signal, and the signal is amplified by the radio frequency amplifier; the power attenuation module is used to attenuate the amplified electrical signal with different power level values ​​according to the attenuation control signal provided by the control component, output a power attenuation signal, and send it to the receiving end of the wireless altimeter.

[0032] Among them, the delay control signal and the attenuation control signal of the control component are set according to actual needs.

[0033] The delay module is the core module of the radio altimeter detector, which is used to simulate the signal delays of different times generated by aircraft at different altitudes; the optical transmitter module, optical receiver module, and radio frequency amplifier module are a series of auxiliary operations to convert the electrical signal of the radio altimeter into a signal that can be received by the delay module. The power attenuation module is used to detect the sensitivity parameters of the radio altimeter transceiver.

[0034] The optical transmitter converts the electrical signal from the radio altimeter transceiver into the optical signal required by the optical fiber delay line, and inputs the optical signal into the delay module after the electrical / optical conversion; the delay module has the characteristic of delay time for the input optical signal, and performs different time delays (corresponding to different simulated altitudes) under the control of the control component;

[0035] The delay module includes a plurality of optical switches, a plurality of delay lines, and a high-precision adjustable mechanical delay device with a precision of 0.001 mm and a range of 1; wherein:

[0036] The optical switches are arranged on the optical path at intervals, and each adjacent optical switch is connected by a different delay line, and the last optical switch is connected to a mechanical delay device; the functions of the optical switches are as follows: when all the optical switches are closed, the optical signal passes through the optical switch and the optical path normally without delay; when a certain optical switch is opened, the optical signal passing through the optical switch will enter the delay line for delay before reaching the next optical switch; through the combination of delay lines of different lengths and different optical switches, the coarse delay of the optical signal at different times is realized, thereby corresponding to different heights; after the delay module receives the delay control signal output by the control component, it determines the opening and closing combination form of the optical switch.

[0037] In this embodiment, it is composed of 13 identical optical fiber delay lines F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, F12, F13 optical switches K1, K2, K3, K4, K5, K6, K7, K8, K9, K10, K11, K12, K13, K14 optical switches, and mechanical delay devices. When the optical fiber delay line uses optical signals as the transmission medium, optical fibers with small transmission loss, strong anti-electromagnetic interference ability, small size, small weight, and stable delay performance should be selected. Therefore, the optical fiber delay line uses a G.652 type optical fiber core with a wavelength of 1310nm, a loss of 0.31dB / m, and a refractive index of 1.4706. Through calculation, the delay line lengths corresponding to the simulated heights of 1m, 2m, 3m, 4m, 10m, 20m, 30m, 40m, 100m, 200m, 300m, 400m, and 1000m are 1.36m, 2.72m, 4.08m, 5.44m, 13.6m, 27.2m, 40.8m, 54.4m, 136m, 272m, 408m, 544, and 1360m, respectively. The optical switches selected are magneto-optical switches with fast switching speed, low loss, and simple control. The specific combinations for the simulated heights are as follows: 5m=1m+4m corresponds to F1+F4, 81m=1m+10m+30m+40m=F1+F5+F7+F8.

[0038] The mechanical delay device is as follows Figure 5As shown, a stepper motor 13 is installed at one end of the upper surface of the base plate 14, and the output shaft of the stepper motor 13 is connected to a lead screw 15. A guide rail 3 is provided on the upper surface of the base plate 14, and a slidable corner cube prism bracket 2 is installed on the guide rail 3 through a slider 7, and the corner cube prism 1 is installed on the corner cube prism bracket 2; the lead screw 15 is threadedly matched with the corner cube prism bracket 2, and the lead screw 15 rotates under the drive of the stepper motor 13, driving the corner cube prism bracket 2 to drive the corner cube prism 1 to move on the guide rail 3; the collimator bracket 12 is installed on the base plate 14, and the last optical switch is connected to the collimator 11 installed on the collimator bracket 12 through an optical fiber 16. After the optical signal output from the output end of the collimator 11 is reflected by the corner cube prism 1 and received by the receiving end of the collimator 11, the delay caused by the distance difference generated when the optical signal propagates between the collimator and the corner cube prism 1 is used to achieve high-precision delay adjustment of the optical signal.

[0039] The collimator is used to reduce the divergence angle of the light beam emitted by the light emission and reduce the insertion loss. The corner cube prism is used to change the propagation line of the light beam. The stepper motor is used to change the horizontal position of the corner cube prism to produce the corresponding simulated height (delay time).

[0040] During operation, the output end of the collimator 11 emits a light signal, the corner cube prism 1 reflects the incident light in parallel, and the receiving end of the collimator couples it into the optical fiber 16 for transmission again; the delay amount of the light is changed by the stepper motor driving the distance from the corner cube prism 1 to the collimator to achieve continuous adjustment.

[0041] The motor takes into account the functions of forward and reverse operation and step-by-step operation of the corner cone prism, so a two-phase four-wire stepper is used for control. Since the delay time of 1m of light transmission is about 6000ps, for the mechanical adjustment module, the length of the guide rail is 500mm, and the accuracy of each step of the stepper motor is better than 1ps, so the accuracy of the high-precision mechanical delay module fully meets the accuracy requirement of 0.001m. In this embodiment, the bottom of the slider 7 cooperates with the guide rail 3 through the steel ball 8 and the retainer 10, and a dustproof sheet 9 is set at the bottom of the steel ball 8; in order to ensure smooth sliding of the slider 7, an oil nozzle 4 for providing lubricating oil is set on the end cover 6 of the slider 7, and the lubricating oil is applied using an oil scraper 5.

[0042] The function of the optical receiver is to convert the optical signal carrying information into an electrical signal in proportion. Therefore, the currently mature direct detection receiver is adopted. The photodetector in the optical receiver adopts a PIN photodiode which is insensitive to temperature changes and has a fast response speed. After the photoelectric conversion is realized, the radio frequency electrical signal is amplified and sent to the power attenuation module. The power attenuation module attenuates the electrical signal according to the power attenuation value sent by the control component, and finally inputs the receiving port of the radio altimeter transceiver.

Claims

1. A continuously adjustable radio altimeter detector, characterized in that: It includes a control component, an optical transmitter, an optical receiver, a delay module, a radio frequency amplifier, and a power attenuation module, wherein: The input end of the optical transmitter is connected to the electrical signal of the radio altimeter, the output end of the optical transmitter is connected to the input end of the delay module, the output end of the delay module is connected to the input end of the optical receiver, the output end of the optical receiver is connected to the input end of the radio frequency amplifier, and the output end of the frequency amplifier is connected to the input end of the power attenuator; the electrical signal of the radio altimeter enters the optical transmitter and is converted into an optical signal and then enters the delay module, the delay module receives the delay control signal output by the control component, determines the delay time of the optical signal, and uses different optical switch on and off combinations with mechanical delays to achieve different time delays for the optical signal, the delayed optical signal enters the optical receiver and is converted into an electrical signal, and the signal is amplified by the radio frequency amplifier; the power attenuation module is used to attenuate the amplified electrical signal with different power level values ​​according to the attenuation control signal provided by the control component, output a power attenuation signal, and send it to the wireless altimeter.

2. The continuously adjustable radio altimeter detector according to claim 1, characterized in that: The delay module includes multiple optical switches and multiple delay lines. The optical switches are arranged at intervals on the optical path, and each adjacent optical switch is connected by a different delay line. When all the optical switches are closed, the optical signal passes through the optical switch and the optical path normally without delay. When a certain optical switch is opened, the optical signal passing through the optical switch will enter the delay line for delay before reaching the next optical switch. Through the combination of delay lines of different lengths and different optical switches, the coarse delay of the optical signal at different times is realized, thereby corresponding to different height signal simulations.

3. The continuously adjustable radio altimeter detector according to claim 2, characterized in that: The delay line uses a G.652 type optical fiber delay line with a wavelength of 1310 nm, a loss of 0.31 dB / m, and a refractive index of 1.4706 in the optical fiber core.

4. The continuously adjustable radio altimeter detector according to claim 2, characterized in that: The delay line lengths corresponding to the simulation heights of 1m, 2m, 3m, 4m, 10m, 20m, 30m, 40m, 100m, 200m, 300m, 400m and 1000m are 1.36m, 2.72m, 4.08m, 5.44m, 13.6m, 27.2m, 40.8m, 54.4m, 136m, 272m, 408m, 544 and 1360m, and the optical switch is a magneto-optical switch.

5. The continuously adjustable radio altimeter detector according to claim 1, characterized in that: The delay control signal and attenuation control signal of the control component are set according to actual needs.

6. The continuously adjustable radio altimeter detector according to claim 1, characterized in that: The last optical switch of the delay module is connected to the mechanical delay device; A stepper motor (13) is installed at one end of the upper surface of a bottom plate (14) of the mechanical delay device, the output shaft of the stepper motor (13) is connected to a screw rod (15), a guide rail (3) is provided on the upper surface of the bottom plate (14), a slidable corner cube prism bracket (2) is installed on the guide rail (3) via a slider (7), and the corner cube prism (1) is installed on the corner cube prism bracket (2); the screw rod (15) is threadedly matched with the corner cube prism bracket (2), and the screw rod (15) is driven by the stepper motor (13) to rotate, driving the corner cube prism bracket (2) to drive ... The movable corner cube prism (1) moves on the guide rail (3); the collimator bracket (12) is mounted on the base plate (14); the last optical switch is connected to the collimator (11) mounted on the collimator bracket (12) via an optical fiber (16); the optical signal output from the output end of the collimator (11) is reflected by the corner cube prism (1) and received by the receiving end of the collimator (11); the delay caused by the distance difference generated when the optical signal propagates between the collimator and the corner cube prism (1) is used to achieve high-precision delay adjustment of the optical signal.

7. The continuously adjustable radio altimeter detector according to claim 1, characterized in that: The bottom of the slider (7) cooperates with the guide rail (3) through a steel ball (8) and a retainer (10), and a dustproof sheet (9) is arranged at the bottom of the steel ball (8); in order to ensure smooth sliding of the slider (7), an oil nozzle (4) for providing lubricating oil is arranged on the end cover (6) of the slider (7), and the lubricating oil is applied by using an oil scraper (5).

8. The continuously adjustable radio altimeter detector according to claim 1, characterized in that: The optical receiver adopts a direct detection receiver, and the photodetector in the optical receiver adopts a PIN photodiode which is insensitive to temperature changes and has a fast response speed.

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