Inertial integrated navigation system for aircraft

Abstract

The utility model provides an inertia combined navigation system for airplane, including the power module of inertia combined navigation system includes the isolation type DC DC power unit and non -isolated type DC DC power unit in series, and is equipped with two common mode filter circuitry at the input port of isolation type DC DC power unit, is equipped with LC filter circuitry between the output port of isolation type DC DC power unit and the input port of non -isolated type DC DC power unit, every switch pin of non -isolated type DC DC power unit is equipped with RC absorption circuitry, and the distance of target RC absorption circuitry distance and the switch pin of this target RC absorption circuitry connection is less than first preset distance, and the distance of target RC absorption circuitry distance and the ground pin of this target RC absorption circuitry connection is less than second preset distance. The utility model provides an inertia combined navigation system with higher electromagnetic compatibility.

Description

Technical Field

[0001] This utility model belongs to the field of electromagnetic compatibility technology, and more specifically, it relates to an inertial navigation system for aircraft. Background Technology

[0002] An inertial navigation system is a modular device that uses an inertial navigation system as its core and integrates or connects to other types of navigation systems, such as GNSS and radio navigation, to achieve higher precision and higher reliability navigation by leveraging the complementary advantages of multiple navigation sources.

[0003] In aircraft navigation and control systems, the inertial navigation system is the core navigation component. Its role is not only to provide basic position, velocity, and attitude information, but also to directly affect flight safety, flight control accuracy, and mission reliability in complex environments.

[0004] Aircraft are highly integrated and complex electronic systems operating in extremely harsh electromagnetic environments, and inertial navigation systems are their core navigation source. If an inertial navigation system malfunctions due to insufficient electromagnetic compatibility, it will directly impact flight safety. Utility Model Content

[0005] This utility model provides an inertial navigation system for aircraft to solve the problem that current inertial navigation systems for aircraft have weak electromagnetic interference resistance and are highly susceptible to electromagnetic interference.

[0006] This utility model provides an inertial navigation system for aircraft. The power module of the inertial navigation system includes an isolated DC-DC power supply unit and a non-isolated DC-DC power supply unit connected in series. A two-stage common-mode filter circuit is provided at the input port of the isolated DC-DC power supply unit, and an LC filter circuit is provided between the output port of the isolated DC-DC power supply unit and the input port of the non-isolated DC-DC power supply unit.

[0007] Each switching pin of the non-isolated DC-DC power supply unit is equipped with an RC snubber circuit, and the distance between the target RC snubber circuit and the switching pin connected to the target RC snubber circuit is less than a first preset distance, and the distance between the target RC snubber circuit and the grounding pin connected to the target RC snubber circuit is less than a second preset distance; wherein, the first preset distance is determined based on the maximum allowable inductive reactance, the second preset distance is determined based on the maximum allowable radiated noise intensity, and the target RC snubber circuit is any RC snubber circuit.

[0008] In one possible implementation, the circuit board of the inertial navigation system has a reserved position for installing a power supply shield, which is used to cover the topology of the isolated DC-DC power supply unit and the non-isolated DC-DC power supply unit corresponding to the power module.

[0009] In one possible implementation, the inertial navigation system also includes a receiver with a GPS unit inside. The circuit board of the inertial navigation system also has a reserved position for installing a GPS shield, which is used to cover the GPS unit.

[0010] In one possible implementation, the inertial navigation system is further provided with a metal outer shell shield, which includes a metal upper shell and a metal lower shell, and the metal upper shell and the metal lower shell are fastened together in a labyrinth structure.

[0011] In one possible implementation, the snap-fit ​​joints of the upper and lower metal shells are coated with a conductive coating.

[0012] In one possible implementation, the screw posts on the inertial navigation system circuit board are connected to the metal housing shield, and the metal housing shield is grounded.

[0013] In one possible implementation, the metal casing of the aviation plug of the inertial navigation system is coated with a conductive coating.

[0014] In one possible implementation, the metal housing corresponding to the aviation plug of the inertial navigation system adopts a multi-contact crown spring or multi-contact line spring structure.

[0015] In one possible implementation, the inertial navigation system also includes a communication module, and the connection port of the communication module is equipped with a common-mode filter circuit and a differential-mode filter circuit.

[0016] In one possible implementation, the power supply pin of the active crystal oscillator of the inertial navigation system is also equipped with an LC filter circuit or a Π filter circuit.

[0017] This invention addresses the extremely harsh electromagnetic environment of aircraft environments. However, current aircraft inertial navigation systems suffer from poor electromagnetic compatibility, failing to meet aviation requirements. This invention provides an aircraft inertial navigation system that, by adding an isolated DC-DC power supply unit connected in series with a conventional non-isolated DC-DC power supply unit, achieves electrical isolation between the input and output sides, effectively blocking the transmission path of common-mode interference and preventing external interference from entering. Furthermore, a two-stage common-mode filter circuit is installed at the input port of the isolated DC-DC power supply unit to ensure that the amplitude of common-mode interference entering the isolated DC-DC power supply unit is reduced to a minimum. Although the output of the isolated DC-DC power supply unit isolates common-mode interference, high-frequency differential-mode interference may still remain. To further filter out differential-mode interference, an LC filter circuit is installed between the output port of the isolated DC-DC power supply unit and the input port of the non-isolated DC-DC power supply unit to attenuate high-frequency differential-mode interference. In addition, since the power inductor of the non-isolated DC-DC power supply unit generates a strong electromagnetic radiation field when it is working, and the switching transistor generates spike pulses when it is turned on and off, which will form a strong electromagnetic noise source, it is necessary to set an RC absorption circuit on each switching pin of the non-isolated DC-DC power supply unit to further reduce spatial radiation by minimizing the high-frequency noise loop area.

[0018] This application significantly improves the electromagnetic interference resistance of the inertial navigation system by employing an isolated DC-DC power supply unit to cut off the propagation path of external interference and a multi-stage filtering collaborative strategy. Attached Figure Description

[0019] Figure 1 A schematic diagram of an inertial integrated navigation system provided for an embodiment of this utility model;

[0020] Figure 2 A connection diagram of the power module provided in an embodiment of this utility model;

[0021] Figure 3 A schematic diagram of the switching pins of a non-isolated DC-DC power supply unit provided in an embodiment of this utility model. Detailed Implementation

[0022] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0023] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0024] The implementation of this utility model will be described in detail below with reference to the specific accompanying drawings:

[0025] As described in the background section, inertial integrated navigation systems primarily rely on inertial measurement units, such as accelerometers and gyroscopes, to provide initial information, and combine them with other navigation sensors, such as GPS, for data fusion and precise navigation.

[0026] As highly integrated and complex electronic systems, aircraft operate in extremely harsh electromagnetic environments. When an inertial navigation system is subjected to external electromagnetic interference, the inertial measurement unit may output erroneous data, leading to deviations in the system's perception of the aircraft's motion and making it impossible to accurately calculate key parameters such as position, velocity, and attitude. Therefore, inertial navigation systems used in aircraft must possess high electromagnetic compatibility.

[0027] Figure 1 This is a schematic diagram of the structure of an inertial navigation system for aircraft, provided by an embodiment of this utility model. The inertial navigation system includes a power module, a control module, a receiver, a communication module, and an inertial measurement unit (IMU) module. The power module provides stable power support for the entire inertial navigation system, ensuring the normal operation of each module. The control module is the core command center of the system, precisely controlling the operation of the entire system according to preset programs and algorithms. The receiver receives external navigation signals, such as satellite signals. It can accurately capture and analyze these signals, providing the system with additional positioning and navigation reference information. Through data fusion with the IMU module, the external signals acquired by the receiver can further improve the accuracy and reliability of aircraft navigation. The communication module is responsible for data communication and interaction between the modules within the system and with other aircraft systems. The IMU module is a key part of the inertial navigation system, comprehensively utilizing inertial measurement units such as accelerometers and gyroscopes to measure the aircraft's acceleration and angular velocity information.

[0028] like Figure 2As shown, this utility model embodiment provides an inertial navigation system for aircraft. The power module of the inertial navigation system includes an isolated DC-DC power supply unit 210 and a non-isolated DC-DC power supply unit 220 connected in series. A two-stage common-mode filter circuit 230 is provided at the input port of the isolated DC-DC power supply unit 210, and an LC filter circuit 240 is provided between the output port of the isolated DC-DC power supply unit 210 and the input port of the non-isolated DC-DC power supply unit 220.

[0029] The main task of an inertial navigation system is high-precision measurement. However, components such as gyroscopes and accelerometers are directly affected by electromagnetic interference from the power supply module. Therefore, in order to minimize the interference from the power supply module and cut off the propagation path of the interference, this application adopts a cooperative strategy of isolation and cutting off the path and multi-level filtering. Since the input and output of the non-isolated DC-DC power supply unit 220 share a common ground and the interference can be directly conducted, resulting in poor electromagnetic compatibility, an isolated DC-DC power supply unit 210 is set in front of it to block the input of external interference.

[0030] The isolated DC-DC power supply unit 210 achieves electrical isolation between the input and output sides, effectively improving electromagnetic compatibility and blocking the conduction path of common-mode interference, as well as suppressing the amplification and propagation of differential-mode interference. Common-mode interference refers to synchronous interference signals generated by the power line relative to ground, and its propagation depends on the common ground path from input ground to output ground. The isolated DC-DC power supply unit 210 cuts off the direct electrical connection between the input and output sides, effectively disconnecting the "cross-domain conduction channel" of common-mode interference. That is, common-mode interference on the input side cannot couple to the output side through ground, avoiding interference with the subsequent non-isolated DC-DC power supply unit 220. At the same time, interference generated on the output side of the non-isolated DC-DC power supply unit 220 cannot be conducted back to the input side, avoiding interference with external devices or components.

[0031] The non-isolated DC-DC power supply unit 220 is only responsible for "secondary voltage regulation", resulting in smaller voltage ripple when outputting to sensitive components, thereby indirectly improving the load's anti-interference capability and enhancing electromagnetic compatibility performance.

[0032] Furthermore, when external interference enters through the power line, common-mode interference accounts for a relatively high proportion, and primary filtering is insufficient to completely attenuate it. Therefore, a secondary common-mode filter needs to be designed to achieve cumulative attenuation, ensuring that the amplitude of common-mode interference entering the isolated DC-DC power supply unit 210 is reduced to an extremely low level. For example, the capacitors selected in the secondary common-mode filter can be TDK 100nF and 1nF 0603 capacitors, and the inductor can be a TDK 1000-ohm 7060.

[0033] Although the output of the isolated DC-DC power supply unit 210 isolates common-mode interference, high-frequency differential-mode interference may still remain, such as ripple generated by the high-frequency switching of the internal switching transistors of the isolated DC-DC unit, typically ranging from 100kHz to 1MHz. If this type of interference directly enters the non-isolated DC-DC power supply unit 220, it will be amplified and transmitted to the load, affecting navigation accuracy. Therefore, an LC filter circuit 240 is needed to attenuate high-frequency differential-mode interference. Furthermore, the LC filter can also help suppress radiated interference between the output of the isolated DC-DC power supply unit 210 and the non-isolated DC-DC power supply unit 220, thereby further improving electromagnetic compatibility. This minimizes interference at the power module output.

[0034] Furthermore, because the power inductor of the non-isolated DC-DC power supply unit 220 generates a strong electromagnetic radiation field during operation, and the switching transistor produces spike pulses during conduction and turn-off, these spikes, together with the power inductor, form a strong electromagnetic noise source. Therefore, in order to reduce electromagnetic interference, such as Figure 3 As shown, an RC snubber circuit needs to be provided on each switching pin of the non-isolated DC-DC power supply unit 220. To minimize the high-frequency noise loop area and further reduce spatial radiation, the distance between the target RC snubber circuit and the switching pin connected to it should be less than a first preset distance, and the distance between the target RC snubber circuit and the ground pin connected to it should be less than a second preset distance. This is achieved by placing the RC snubber circuit as close as possible to the SW pin, preventing noise propagation along long traces. The first preset distance can be determined based on the maximum allowable inductive reactance of the inertial navigation system. The second preset distance is determined based on the maximum allowable radiated noise intensity of the inertial navigation system, allowing components to be placed as close as possible to the SW pin and ground pin during component layout to suppress spatial high-frequency noise generated by the loop area. The target RC snubber circuit can be any RC snubber circuit. Furthermore, for further high-frequency decoupling, a capacitor can be added to each of the voltage output ports of the non-isolated DC-DC power supply unit 210, such as the +3.3V and +1.2V output ports. One end of the capacitor is connected to the voltage output port, and the other end is grounded.

[0035] In some embodiments, the topologies of both isolated and non-isolated DC-DC power units corresponding to the power module generate strong switching noise. This switching noise can couple spatially to nearby traces and ports, resulting in radiated interference. To reduce the noise of the power topology, a location needs to be reserved on the circuit board of the inertial navigation system for installing a power shield. The power shield is used to cover both the isolated and non-isolated DC-DC power unit topologies corresponding to the power module.

[0036] In some embodiments, the receiver in the inertial navigation system is also equipped with a GPS unit. The GPS unit is a high-frequency radiation source, and the interference generated by the GPS unit can easily couple to the low-frequency port through space. In order to reduce the high-frequency radiation of the GPS unit, it is also necessary to reserve a position on the circuit board of the inertial navigation system to install a GPS shield. The GPS shield is used to cover the GPS unit.

[0037] In some embodiments, since the GPS unit is a high-frequency radiation source, and other radiation sources are also present in the inertial navigation system, a metal outer casing is required to prevent electromagnetic interference to the external system. This metal casing includes an upper metal shell and a lower metal shell, which are joined together using a labyrinth structure. The labyrinth structure is fabricated on the upper and lower metal shells. These grooves and protrusions form complex channels, which, when joined together, create a unified shield, thus reducing the outward radiation of internal interference. This also reduces external interference to the inertial navigation system.

[0038] In this embodiment, in order to ensure good conductivity, a conductive coating is also applied to the interlocking joint of the upper and lower metal shells to ensure that the interlocking joint is not polarized.

[0039] In this embodiment, to further improve the electromagnetic compatibility of the inertial navigation system, the screw posts on the inertial navigation system circuit board can be connected to a metal housing shield. The metal housing shield is grounded, which reduces electromagnetic leakage caused by gaps or holes, forms a continuous grounding path, and reduces the radiation or coupling of high-frequency electromagnetic waves. Furthermore, ungrounded metal screw posts may act as radiating antennas; grounding suppresses their antenna effect.

[0040] In some embodiments, the metal casing of the aviation connector is a crucial element of the system's electromagnetic shielding. It must block external radiated interference from entering the system while preventing internal interference from radiating outwards through the connector. Therefore, to further improve the electromagnetic compatibility of the inertial navigation system, a conductive coating can be applied to the metal casing of the aviation connector to ensure the shielding layer remains conductive regardless of the insertion angle. Conductive coatings, such as conductive silver paste, nickel-based coatings, and graphene conductive films, function primarily to form an "electromagnetic shielding barrier" on the outside of the connector. When exposed to complex electromagnetic environments such as radio frequency signals and pulse interference, the conductive coating, like a metal casing, can "reflect" or "absorb" external electromagnetic energy, preventing interference from entering through gaps in the aviation connector. It can also suppress the outward radiation of internal interference.

[0041] In this embodiment, the metal casing corresponding to the aviation plug can also adopt a multi-contact crown spring or multi-contact wire spring structure, and the multiple contacts can avoid the interruption of the grounding path.

[0042] In some embodiments, the inertial navigation system also includes a communication module. Internal interference can be transmitted through the communication module. Therefore, a common-mode filter circuit and a differential-mode filter circuit are required at the connection port of the communication module. The core of the common-mode filter circuit is to suppress the flow of common-mode interference current, while the differential-mode filter circuit is designed for differential-mode interference and its core is to suppress interference coupling between signal lines.

[0043] In some embodiments, active crystal oscillators can also interfere with inertial navigation systems. A ceramic capacitor can be placed at the power supply pin of the active crystal oscillator to filter out high-frequency noise. An electrolytic capacitor can also be connected in parallel to filter out low-frequency noise. Furthermore, an LC filter circuit or a π filter circuit can be placed on the power supply pin of the active crystal oscillator to further suppress high-frequency noise. Additionally, a ferrite bead can be connected in series on the power supply line of the active crystal oscillator to effectively suppress high-frequency noise.

[0044] In some embodiments, the circuit board of the inertial navigation system can be designed in a stacked manner, such as a six-layer board, with layers S1, G1, S2, POWER, G2, and S3. The first layer, S1, serves as the core layout and high-frequency signal layer of the system. Key components such as the MCU, IMU sensor, and GPS module are centrally located on the S1 layer, shortening the signal path to reduce delay and interference. It also handles high-frequency / high-speed digital signal traces, such as the data bus (SPI / I2C) between the IMU and MCU, the GPS digital interface, and system control signals. Impedance control (e.g., 50Ω single-ended) and radiation suppression are achieved by being adjacent to the lower ground layer (G1), ensuring short-path (≤5cm) transmission of sensitive signals (such as IMU data). It is the "signal interaction center" of the system.

[0045] The second layer, G1, is the top ground layer, a hybrid layer of power ground and digital ground. As one of the main ground planes of the system, the G1 layer carries the power ground and digital ground loops, providing low-impedance ground return for top-level power devices (such as DC-DC and motor drives) and digital circuits. It reduces ground impedance noise through high-current path design (copper thickness ≥ 1 oz). Its core function is to achieve noise isolation and high-frequency discharge: the power ground and GPS signal ground island are connected through two reserved 0603 bridging capacitors (100pF + 1nF), which isolates low-frequency power noise (<1MHz) and quickly discharges high-frequency interference (>100MHz) through the capacitors, making it a "ground noise barrier" for the system.

[0046] The third layer, S2, is the middle signal layer, which is used for the isolation and transmission of analog signals and low-speed bus. It is mainly used for the isolation and transmission of analog signals and low-speed control signals. The S2 layer mainly carries the analog output of the IMU (accelerometer / angular velocity analog quantity). By staying away from the high-frequency digital noise and power ground current fluctuations of the top layer, the purity of the analog signal is ensured. At the same time, it carries low-speed buses (such as I2C peripherals and temperature sensors) with a rate ≤400kHz. By laying ground on both sides (connecting to the G2 ground layer), an "analog signal-ground" shield is formed, which is the "high-precision signal channel" of the system.

[0047] The fourth layer, POWER, is the power supply layer and serves as the central hub for the system's centralized power supply. The POWER layer is functionally divided into independent areas such as the digital core power supply (3.3V_DIG), analog sensor power supply (3.3V_ANA), and power drive power supply (5V_PWR). Crosstalk between power supplies is avoided through isolation strips (≥0.5mm). Distributed capacitors are formed by using 2oz thick copper and the upper and lower ground layers (G1, G2) to filter out high-frequency ripple (especially 3.3V_ANA, which needs to have ≤1mV ripple), providing low-noise power supply for high-precision modules such as IMU and GPS. It is the system's "energy distribution and noise filtering center".

[0048] The fifth layer, G2, is the bottom ground layer, a dedicated layer for analog and radio frequency ground. As the second ground plane of the system, the G2 layer is dedicated to providing a low-noise ground reference for analog circuits and GPS radio frequency: as a "clean ground" to carry the ground return current of the IMU analog circuit and ADC, it isolates digital noise from the top power ground (G1) through a single-point grounding (0Ω resistor / ferrite bead); at the same time, it builds a local "radio frequency ground island" for the GPS radio frequency module, and ensures low impedance return current of radio frequency signals through multi-point via connections, making it the "clean ground reference plane for analog and radio frequency signals" of the system.

[0049] Layer 6, S3, is the bottom signal layer, responsible for transmitting auxiliary function signals of the system. It mainly houses non-sensitive signals such as debugging interfaces (JTAG / UART), indicator lights, and low-speed peripherals (EEPROM, buzzer), with a speed ≤100kHz and no strict impedance requirements. At the same time, it provides power and ground paths for the bottom connectors, connecting to the POWER layer and G2 ground layer through vias to avoid interference with the core signal layer. It is the system's "auxiliary function expansion channel".

[0050] This invention addresses the extremely harsh electromagnetic environment of aircraft environments. However, current aircraft inertial navigation systems suffer from poor electromagnetic compatibility, failing to meet aviation requirements. This invention provides an aircraft inertial navigation system that, by adding an isolated DC-DC power supply unit connected in series with a conventional non-isolated DC-DC power supply unit, achieves electrical isolation between the input and output sides, effectively blocking the transmission path of common-mode interference and preventing external interference from entering. Furthermore, a two-stage common-mode filter circuit is installed at the input port of the isolated DC-DC power supply unit to ensure that the amplitude of common-mode interference entering the isolated DC-DC power supply unit is reduced to a minimum. Although the output of the isolated DC-DC power supply unit isolates common-mode interference, high-frequency differential-mode interference may still remain. To further filter out differential-mode interference, an LC filter circuit is installed between the output port of the isolated DC-DC power supply unit and the input port of the non-isolated DC-DC power supply unit to attenuate high-frequency differential-mode interference.

[0051] In addition, since the power inductor of the non-isolated DC-DC power supply unit generates a strong electromagnetic radiation field when it is working, and the switching transistor generates spike pulses when it is turned on and off, which will form a strong electromagnetic noise source, it is necessary to set an RC absorption circuit on each switching pin of the non-isolated DC-DC power supply unit to further reduce spatial radiation by minimizing the high-frequency noise loop area.

[0052] This application significantly improves the electromagnetic interference resistance of the inertial navigation system by employing an isolated DC-DC power supply unit to cut off the propagation path of external interference and a multi-stage filtering collaborative strategy.

[0053] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An inertial navigation system for aircraft, characterized in that, The power module of the inertial navigation system includes a series-connected isolated DC-DC power unit and a non-isolated DC-DC power unit. A two-stage common-mode filter circuit is provided at the input port of the isolated DC-DC power unit, and an LC filter circuit is provided between the output port of the isolated DC-DC power unit and the input port of the non-isolated DC-DC power unit. Each switching pin of the non-isolated DC-DC power supply unit is provided with an RC snubber circuit, and the distance between the target RC snubber circuit and the switching pin connected to the target RC snubber circuit is less than a first preset distance, and the distance between the target RC snubber circuit and the grounding pin connected to the target RC snubber circuit is less than a second preset distance; wherein, the first preset distance is determined based on the maximum allowable inductive reactance, the second preset distance is determined based on the maximum allowable radiated noise intensity, and the target RC snubber circuit is any RC snubber circuit.

2. The inertial navigation system for aircraft as described in claim 1, characterized in that, The circuit board of the inertial navigation system has a reserved position for installing a power supply shield. The power supply shield is used to cover the topology of the isolated DC-DC power supply unit and the topology of the non-isolated DC-DC power supply unit corresponding to the power module.

3. The inertial navigation system for aircraft as described in claim 2, characterized in that, The inertial navigation system also includes a receiver, which contains a GPS unit. The circuit board of the inertial navigation system also has a reserved position for installing a GPS shield, which is used to cover the GPS unit.

4. The inertial navigation system for aircraft as described in claim 1, characterized in that, The inertial navigation system is also equipped with a metal outer shell shield, which includes an upper metal shell and a lower metal shell, and the upper metal shell and the lower metal shell are fastened together in a labyrinth structure.

5. The inertial navigation system for aircraft as described in claim 4, characterized in that, The mating joints of the upper and lower metal shells are coated with a conductive coating.

6. The inertial navigation system for aircraft as described in claim 4 or 5, characterized in that, The screw posts on the circuit board of the inertial navigation system are connected to the metal housing shield, and the metal housing shield is grounded.

7. The inertial navigation system for aircraft as described in claim 1, characterized in that, The metal casing of the aviation plug of the inertial navigation system is coated with a conductive coating.

8. The inertial navigation system for aircraft as described in claim 7, characterized in that, The metal casing corresponding to the aviation plug of the inertial navigation system adopts a multi-contact crown spring or multi-contact line spring structure.

9. The inertial navigation system for aircraft as described in claim 1, characterized in that, The inertial navigation system also includes a communication module, and the connection port of the communication module is provided with a common-mode filter circuit and a differential-mode filter circuit.

10. The inertial navigation system for aircraft as described in claim 1, characterized in that, The power supply pin of the active crystal oscillator of the inertial navigation system is also equipped with an LC filter circuit or a Π filter circuit.

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