Field-circuit combined aircraft airborne equipment high-intensity radiation field conducted interference assessment method

Abstract

The invention provides a field-circuit combined airplane airborne equipment high-intensity radiation field conducted interference assessment method. The method comprises the steps that S1, interference current Iout (f) induced by an airborne equipment cable is solved through airplane HIRF effect simulation; s2, calculating the shielding effectiveness S (f) of the shielded wire through an airborne equipment cable transfer impedance test; s3, calculating the interference current Iin (f) of the pin end of the onboard equipment based on the Iout (f) and the S (f); s4, establishing an airborne equipment circuit simulation model; and S5, simulating and analyzing the airborne equipment circuit response when the Iin (f) is injected through the airborne equipment circuit simulation model. According to the method, the problem of prediction and evaluation of HIRF interference on airborne equipment in the aircraft HIRF protection design process is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft high-intensity radiation field protection design, and in particular to a field-circuit combined high-intensity radiation field conduction interference assessment method for aircraft onboard equipment. Background Art

[0002] High-intensity radiated fields (HIRF) refer to the electromagnetic environment created by radiation from high-power transmitters such as radar, radio, navigation, and broadcast television on the ground, ships, offshore platforms, or aircraft. With the widespread use of composite materials in aircraft structures and the increasing integration of onboard equipment, the impact of HIRF on aircraft safety has become increasingly prominent. HIRF environments expose aircraft equipment to potential electromagnetic damage, primarily due to interference coupling between strong external electromagnetic fields and onboard equipment. Electromagnetic energy from the external HIRF environment enters the aircraft interior through apertures such as windshields, windows, and doors, or through composite airframe structures, generating induced electromagnetic fields within the cabin. These induced electromagnetic fields can couple through apertures into electronic equipment, radiating interference to internal modules, board-level circuits, and components. They can also induce currents in equipment cables through field line coupling, conducting interference to internal circuits. When radiated interference or conducted interference exceeds the sensitive threshold of equipment and components, electronic equipment will experience performance degradation and malfunction. In severe cases, components may even be damaged or burned. Specific phenomena include malfunction of the control system's control surfaces, sudden changes in engine speed, interference with radio communications, and incorrect display of navigation parameters such as indicated heading and altitude. When HIRF interference is severe, flight accidents such as loss of control and crashes of the aircraft may also occur.

[0003] Therefore, it is extremely necessary to evaluate and analyze the impact of the HIRF environment on the internal circuits of key aircraft onboard equipment during the aircraft design phase. In particular, it is necessary to evaluate and analyze the impact of the HIRF environment on the conducted interference of airborne equipment, which is the main interference coupling path, by focusing on field line coupling. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for evaluating the high-intensity radiation field conduction interference of aircraft onboard equipment. The present invention solves the problem of predicting and evaluating the HIRF interference of onboard equipment during the aircraft HIRF protection design process.

[0005] Technical Solution: A field-circuit combined method for evaluating high-intensity radiation field conduction interference of aircraft onboard equipment includes the following steps: S1. Calculate the interference current induced by cables in airborne equipment through aircraft HIRF effect simulation I out ( f ); S2. Calculate the shielding effectiveness of shielded cables through the transfer impedance test of airborne equipment cables S ( f); S3. Based on I out ( f ), S ( f ), computer onboard device pin-end interference current I in ( f ) ; S4. Establish a circuit simulation model for airborne equipment; S5. Injection analysis through airborne equipment circuit simulation model I in ( f ) when the airborne equipment circuit responds.

[0006] In S1 of the aforementioned field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method, I out ( f ) is the interference current solved on the shielding layer of the airborne equipment harness model when the aircraft electromagnetic model is irradiated with a plane wave of HIRF environmental level as the excitation source.

[0007] In the aforementioned field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method, I out ( f ) is solved as follows: Import the aircraft structure model into the electromagnetic simulation software, simplify, repair, and mesh it into the aircraft electromagnetic model; for the airborne equipment to be evaluated, establish and simplify its harness model in the electromagnetic simulation software, define the cross-section and nodes of the harness, irradiate the aircraft electromagnetic model with a plane wave, calculate the near-field distribution along the 3D path of the harness, use the obtained near-field value as the input source of the harness, calculate the induced current at the harness test point, and thus give the interference current induced by the cables of the airborne equipment I out ( f ).

[0008] In the aforementioned field-circuit combined method for evaluating conducted interference of high-intensity radiation fields of aircraft-borne equipment, the near-field distribution is calculated using a full-wave algorithm.

[0009] In S2 of the aforementioned field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method, S ( f ) is: The electromagnetic protection sheath or shielding layer of the airborne equipment cable is used as the test sample, and the shielding effectiveness of the shielding wire is calculated by testing the transfer impedance using the frequency domain triaxial method.

[0010] In S3 of the aforementioned field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method,I in ( f ) is calculated as follows: I in ( f ) = I out ( f ) / S ( f ).

[0011] In the aforementioned field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference evaluation method, S4 is specifically as follows: combined with the internal circuit schematic diagram of the airborne equipment, a circuit simulation model of the airborne equipment is established and simplified in the circuit simulation software, the input and output ports of the airborne equipment circuit simulation model are defined, and the normal working signal excitation source of the simulation model is set.

[0012] In the above-mentioned field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method S5, the onboard equipment circuit response is: I in ( f ) is the circuit response generated at the output port of the airborne equipment circuit simulation model when another excitation source is superimposed on the normal working signal excitation source of the airborne equipment circuit simulation model input port.

[0013] The aforementioned field-circuit combined method for evaluating high-intensity radiation field conduction interference of aircraft onboard equipment also includes S6: comparing the circuit response of the onboard equipment obtained in S5 with the normal output signal or normal response state of the airborne equipment circuit simulation model to determine whether it exceeds the threshold of the normal output signal or the indicator of the normal response state.

[0014] Beneficial effects: The present invention transfers the HIRF effect simulation results at the aircraft level and the cable transfer impedance and shielding effectiveness characteristics at the equipment level to the internal circuit HIRF interference response at the circuit level through a field-circuit combination method, thereby achieving the purpose of accurately predicting the aircraft HIRF effect from top to bottom. In the aircraft HIRF protection design stage, the degree of influence of HIRF interference on airborne equipment can be explicitly and quantitatively predicted, and the aircraft HIRF protection design from the aircraft level, system equipment level to the circuit level can be accurately quantified, as well as the top-down rapid iteration in the early stage of development can be achieved, effectively avoiding over-design and under-design problems, avoiding repeated changes in the later stage of development, improving development efficiency, and reducing development costs.

[0015] In summary, the present invention achieves explicit characterization of the prediction and evaluation of HIRF interference on aircraft onboard equipment. The present invention will have a positive effect and value on the design of aircraft HIRF protection and the safety assessment and analysis of aircraft affected by HIRF. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flowchart of the field-circuit combined high-intensity radiation field conduction interference assessment of aircraft onboard equipment. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0018] Example 1. A method for evaluating high-intensity radiation field conduction interference of aircraft onboard equipment combined with field circuit, see Figure 1 ,include: Aircraft HIRF effect simulation analysis of interference current induced by cables of airborne equipment: obtain the aircraft structure model and import it into the electromagnetic simulation software, and simplify, repair and mesh it into the aircraft electromagnetic model. For the airborne equipment to be evaluated, establish and simplify its harness model in the electromagnetic simulation software, define the cross section and nodes of the harness, irradiate the aircraft electromagnetic model with a plane wave, calculate the near-field distribution along the 3D path of the harness, use the obtained near-field value as the input source of the harness, calculate the induced current at the harness test point, and thus give the interference current induced by the cables of the airborne equipment. I out ( f ); Transfer impedance test of airborne equipment cables to calculate the shielding effectiveness of shielded cables: For airborne equipment cables with electromagnetic shielding sleeves or shielding layers to be evaluated, the electromagnetic shielding sleeves or shielded cables are used as test specimens. The frequency domain transfer impedance test is performed using the triaxial method to determine the shielding effectiveness of the electromagnetic shielding sleeves or shielded cables. S ( f ); Interference current at the pin end of the computer onboard equipment: interference current induced by the cable of the onboard equipment obtained based on simulation I out ( f ) and transfer impedance test to obtain the shielding effectiveness of electromagnetic shielding sleeves or shielded wires S ( f ), calculate the interference current at the pin end of the onboard device in the frequency domain I in ( f ) = I out ( f ) / S ( f ); Establish a circuit simulation model for the airborne equipment: Based on the internal circuit schematic of the airborne equipment, establish and simplify the circuit simulation model of the airborne equipment in the circuit simulation software, define the input and output ports of the airborne equipment circuit simulation model, and set the normal operating signal excitation source of the simulation model; Simulate and analyze the circuit response of airborne equipment: Use the interference current at the pin end of the airborne equipment as another excitation source and superimpose it on the normal working signal of the input port of the circuit simulation model. Simulate and analyze the interference response of the airborne equipment after the interference current is injected into the pin end, and compare it with the normal output signal or normal response state of the circuit simulation model to determine whether it exceeds the threshold of the normal output signal or the indicator of the normal response state.

[0019] Example 2. Figure 1 As shown, a field-circuit-combined method for evaluating high-intensity radiated field conduction interference of aircraft onboard equipment is used to predict and evaluate HIRF interference of airborne equipment during the aircraft HIRF protection design process. The specific steps of the method for evaluating high-intensity radiated field conduction interference of aircraft onboard equipment are as follows: Step 1. Import the aircraft structure model into the electromagnetic simulation software, simplify, repair and mesh it into the aircraft electromagnetic model. For the airborne equipment to be evaluated, establish and simplify its harness model in the electromagnetic simulation software, define the cross-section of the harness, set the diameter of the metal wire core, the thickness of the insulating medium, the thickness of the metal shielding layer, etc., define the nodes at the harness terminals, and set the circuit and impedance parameters of the nodes (such as resistance, inductance, and capacitance values); irradiate the aircraft electromagnetic model with a plane wave, use the full-wave algorithm to calculate the near-field distribution along the 3D path of the harness, use the obtained near-field value as the input source of the harness, calculate the induced current at the harness test point, and thus give the interference current induced by the airborne equipment cable I out ( f ); Step 2: Determine whether the airborne equipment cable is a shielded cable. For the airborne equipment cable to be evaluated with an electromagnetic protective cover or shielding layer, use the electromagnetic protective cover or shielding cable as the test sample and use the triaxial method to perform frequency domain transfer impedance test to obtain the shielding effectiveness of the electromagnetic protective cover or shielding cable. S ( f ); Step 3: Interference current induced by airborne equipment cables based on simulation I out ( f ) and transfer impedance test to obtain the shielding effectiveness of electromagnetic shielding sleeves or shielded wires S ( f ), calculate the interference current at the pin end of the onboard device in the frequency domain I in ( f ) = I out ( f ) / S ( f ); Step 4: Based on the internal circuit schematic of the airborne equipment, establish and simplify a circuit simulation model of the airborne equipment in the circuit simulation software, define the input and output ports of the airborne equipment circuit simulation model, and set the normal working signal excitation source of the simulation model; Step 5. Use the interference current at the pin end of the airborne equipment as another excitation source and superimpose it on the normal working signal of the input port of the simulation model. Simulate and analyze the interference response of the airborne equipment after the interference current is injected into the pin end, and compare it with the normal output signal or normal response state of the simulation model to determine whether it exceeds the threshold of the normal output signal or the indicator of the normal response state.

[0020] The advantage of the present invention is that it applies the HIRF effect simulation results at the aircraft level, the cable transfer impedance and shielding effectiveness characteristics at the equipment level, etc. to the internal circuit HIRF interference response at the circuit level, thereby achieving the purpose of field-circuit combined simulation and top-down quantitative prediction of the aircraft HIRF effect, and realizing the explicit characterization of the predictive evaluation of the aircraft's HIRF impact, which will have a positive effect and value on the aircraft HIRF protection design and the safety assessment analysis of the aircraft's HIRF impact.

[0021] Example 3. Figure 1 As shown, the field-circuit combined method for evaluating high-intensity radiation field conduction interference of aircraft onboard equipment adopted in this embodiment is specifically as follows: Step 1: Obtain a certain type of aircraft structure model and import it into electromagnetic simulation software such as Galileo EMT software, and simplify, repair and mesh it into an aircraft electromagnetic model. For the airborne equipment to be evaluated, such as the core processing unit, select the interconnecting cables and remote devices of the core processing unit, establish and simplify its harness model in the Galileo EMT software, define the cross-section of the harness, set the diameter of the metal core, the thickness of the insulating medium, the thickness of the metal shielding layer, etc., define the nodes at the end of the harness, and set the circuit and impedance parameters (resistance, inductance, capacitance values) of the nodes; irradiate the aircraft electromagnetic model with a plane wave, use the full-wave algorithm to calculate the near-field distribution along the 3D path of the harness, use the obtained near-field value as the input source of the harness, calculate the induced current on the harness test point, and thus give the interference current induced by the cables of the airborne equipment such as the core processing unit. I out ( f ), frequency range is 10kHz ~ 400MHz; Step 2: For the bus signal line of the core processing unit with a shielding layer, use this shielded line as a test sample and use the triaxial method to perform frequency domain transfer impedance testing to obtain the shielding effectiveness of this shielded line. S ( f ), frequency range is 10kHz ~ 400MHz; Step 3: Interference current induced by the core processing unit cable based on simulation I out ( f ) and the shielding effectiveness of the shielded cable obtained by the transfer impedance test S ( f ), calculate the interference current at the core processing unit pin end in the frequency domain I in ( f ) = I out ( f ) / S ( f ), frequency range is 10kHz ~ 400MHz; Step 4: Based on the internal circuit schematic diagram of the core processing unit, establish and simplify the circuit simulation model of the core processing unit in the circuit simulation software Spice, define the input and output ports of the circuit simulation model, and set the normal working signals of the circuit simulation model; Step 5. In the circuit simulation software Spice, the interference current at the pin end of the core processing unit is used as another excitation source superimposed on the normal working signal of the input port of the circuit simulation model. The interference response of the core processing unit after the interference current is injected into the pin end is simulated and analyzed, and compared with the normal output signal and normal response state of the core processing unit to determine whether it exceeds the threshold of the normal output signal and the indicator of the normal response state.

Claims

1. A field-circuit combined method for evaluating high-intensity radiation field conduction interference of aircraft onboard equipment, characterized in that: The steps include: S1. Calculate the interference current induced by cables in airborne equipment through aircraft HIRF effect simulation I out ( f ); S2. Calculate the shielding effectiveness of shielded cables through the transfer impedance test of airborne equipment cables S ( f ); S3. Based on I out ( f ), S ( f ), computer onboard device pin-end interference current I in ( f ) ; S4. Establish a circuit simulation model for airborne equipment; S5. Injection analysis through airborne equipment circuit simulation model I in ( f ) when the airborne equipment circuit responds.

2. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 1 is characterized in that: In S1, I out ( f ) is the interference current solved on the shielding layer of the airborne equipment harness model when the aircraft electromagnetic model is irradiated with a plane wave of HIRF environmental level as the excitation source.

3. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 2 is characterized in that: I out ( f ) is solved as follows: Import the aircraft structure model into the electromagnetic simulation software, simplify, repair, and mesh it into the aircraft electromagnetic model; for the airborne equipment to be evaluated, establish and simplify its harness model in the electromagnetic simulation software, define the cross-section and nodes of the harness, irradiate the aircraft electromagnetic model with a plane wave, calculate the near-field distribution along the 3D path of the harness, use the obtained near-field value as the input source of the harness, calculate the induced current at the harness test point, and thus give the interference current induced by the cables of the airborne equipment I out ( f ).

4. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 3 is characterized in that: The near-field distribution is calculated using the full-wave algorithm.

5. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 1 is characterized in that: In S2, S ( f ) is: The electromagnetic protection sheath or shielding layer of the airborne equipment cable is used as the test sample, and the shielding effectiveness of the shielding wire is calculated by testing the transfer impedance using the frequency domain triaxial method.

6. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 1, characterized in that: In S3, I in ( f ) is calculated as follows: I in ( f ) = I out ( f ) / S ( f )。 7. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 1, characterized in that: S4 is specifically as follows: Combined with the internal circuit schematic diagram of the airborne equipment, a circuit simulation model of the airborne equipment is established and simplified in the circuit simulation software, the input and output ports of the circuit simulation model of the airborne equipment are defined, and the normal working signal excitation source of the simulation model is set.

8. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 7, characterized in that: In S5, the circuit response of the airborne equipment is: I in ( f ) is the circuit response generated at the output port of the airborne equipment circuit simulation model when another excitation source is superimposed on the normal working signal excitation source of the airborne equipment circuit simulation model input port.

9. The field-circuit combined aircraft onboard equipment high-intensity radiation field conduction interference assessment method according to claim 1, characterized in that: The method further includes S6: comparing the airborne device circuit response obtained in S5 with a normal output signal or a normal response state of the airborne device circuit simulation model to determine whether the normal output signal threshold or the normal response state indicator is exceeded.

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