Antenna feeder circuit of inertial navigation system

Abstract

The utility model belongs to an inertial navigation system, and particularly relates to an inertial navigation system antenna feeder circuit, which comprises an inertial navigation system and at least two antenna feeder circuits adopting differential signal transmission, and each antenna feeder circuit comprises a feed power supply, an anti-surge module, an anti-backflow module, an isolation module and an anti-static module, the output end of the inertial navigation system is connected with the input end of the feed power supply, the output end of the feed power supply is sequentially connected with the anti-surge module, the anti-backflow module, the isolation module and the anti-static module, and a multi-stage protection link is generated; the multi-stage protection link is integrated on an independent daughter board and is externally connected with a main control board through a metalized connector; the anti-surge module is used for inhibiting voltage impact; the anti-backflow module is used for preventing current from flowing reversely; the isolation module is used for noise isolation; the anti-static module is used for releasing electrostatic charges. The antenna feeder circuit of the inertial navigation system can solve the problem that the antenna feeder circuit of the inertial navigation system in the prior art is weak in protection against power supply surge and electrostatic interference.

Description

Technical Field

[0001] This utility model belongs to the field of inertial navigation systems, and particularly relates to an antenna feeder circuit for an inertial navigation system. Background Technology

[0002] In the field of modern navigation, inertial navigation systems (INS) play a crucial role in aerospace, military equipment, and high-end civilian applications due to their autonomy and continuity. As a key component of INS for receiving satellite signals and external commands, the stability of the antenna feed circuit directly determines the level of navigation accuracy.

[0003] Currently, the antenna feed circuit of an inertial navigation system (INS) typically consists of a power supply and a signal processing module, directly connected to the internal power and signal modules of the INS. However, existing antenna feed circuit designs have several shortcomings. In traditional designs, the antenna is directly connected to the INS via a coaxial cable, the power module is equipped with only a simple fuse, lacking surge suppression and isolation measures, and signal transmission uses a single-ended unshielded cable. This design leads to two major problems for the antenna feed circuit: First, the lack of a power protection mechanism means that when the external power supply fluctuates or is subjected to surge impacts, the surge current can directly damage the internal power module, greatly reducing system reliability. Second, severe signal interference problems occur. During long-distance transmission, the antenna feed line is highly susceptible to electromagnetic interference coupling. Coupled with poor grounding of the coaxial cable shielding layer, common-mode interference cannot be effectively suppressed, resulting in an increased data error rate and seriously affecting navigation accuracy. In addition, the antenna feed circuit lacks reverse protection; if the polarity of the external power supply is reversed, the relevant modules will burn out due to overcurrent. These problems severely restrict the performance improvement and widespread application of inertial navigation systems, and there is an urgent need to optimize the design of antenna feeder circuits to improve their stability and anti-interference capabilities. Utility Model Content

[0004] The technical problem solved by this utility model is to provide an antenna feed circuit for an inertial navigation system, so as to solve the problem of weak protection against power surges and electrostatic interference in the antenna feed circuits of existing inertial navigation systems.

[0005] The basic solution provided by this utility model is as follows: an inertial navigation system antenna feeder circuit, including an inertial navigation system and at least two antenna feeder circuits using differential signal transmission. Each antenna feeder circuit includes a power supply, a surge protection module, a backflow prevention module, an isolation module, and an anti-static module. The output terminal of the inertial navigation system is connected to the input terminal of the power supply. The output terminal of the power supply is sequentially connected to the surge protection module, the backflow prevention module, the isolation module, and the anti-static module to generate a multi-level protection link. The multi-level protection link is integrated on an independent daughterboard and externally connected to the main control board through a metallized connector.

[0006] The surge protection module is used to suppress voltage surges; the backflow prevention module is used to prevent current from flowing in the opposite direction; the isolation module is used for noise isolation; and the antistatic module is used to release static charge.

[0007] Furthermore, the surge protection module includes a TVS diode. The power supply is connected to the positive terminal of the TVS diode after being connected in series with a current-limiting resistor, and the negative terminal of the TVS diode is connected to the backflow prevention module.

[0008] Furthermore, the anti-backflow module includes a second capacitor, a third capacitor, a first inductor, and a second inductor. One end of the second capacitor is connected to the negative terminal of the TVS diode, and the other end is grounded. One end of the third capacitor is connected to the negative terminal of the TVS diode, and the other end is grounded. One end of the first inductor is connected to the negative terminal of the TVS diode, and the other end is connected to the second inductor.

[0009] Furthermore, the other end of the second inductor is connected to a protection diode in reverse and is also connected to the lead of the metallized connector; the other end of the protection diode is grounded.

[0010] Furthermore, the first and second inductors employ π-type filtering, covering a frequency band of 100kHz-1GHz.

[0011] Furthermore, the antenna feed circuit also includes a first capacitor, the anti-static module includes an ESD protection device, the other end of the second inductor is connected to the ESD protection device, and is also connected to the lead of the metallized connector; the signal input of the antenna feed circuit is connected to the ESD protection device after being connected in series with the first capacitor.

[0012] Furthermore, the isolation module is a single-layer shielded cavity, and the shielding effectiveness of the single-layer shielded cavity is ≥60dB.

[0013] Furthermore, the grounding adopts a combination of star grounding and multi-point grounding.

[0014] The principle and advantages of this utility model are as follows: The antenna feed circuit of the inertial navigation system in this application adopts a multi-level protection and differential transmission collaborative design. Specifically, the power supply output first passes through a surge protection module composed of a current-limiting resistor and a TVS diode. The TVS diode quickly clamps transient overvoltages (such as static electricity and surges) and discharges energy to ground. Then, the diode of the anti-backflow module prevents the current from flowing in the opposite direction. In conjunction with the π-type filter circuit (second capacitor, third capacitor, first inductor, second inductor), common-mode and differential-mode noise in the 100kHz-1GHz frequency band is filtered out, achieving preliminary purification of power supply and signal. The single-layer shielded cavity of the isolation module (shielding effectiveness ≥60dB) isolates external noise radiation through electromagnetic shielding. Combined with the ESD protection device of the anti-static module (connected in series with the signal input), it releases static charge, forming a complete protection chain from energy suppression to noise isolation.

[0015] At least two antenna feeder circuits use differential signal transmission, utilizing the phase difference of the signal pairs to cancel common-mode interference and improve anti-interference capability; the grounding system integrates star grounding (reducing the potential difference between each module's ground) and multi-point grounding (reducing the grounding impedance of high-frequency noise) to ensure a fast discharge path for protective devices (such as TVS and ESD) and avoid ground loop interference.

[0016] Finally, the multi-level protection links are integrated into an independent sub-board, which is connected to the main control board through a metallized connector to achieve physical isolation and convenient maintenance. At the same time, the sub-board layout is optimized according to the signal flow direction to shorten the interference path and enhance system reliability.

[0017] Therefore, the advantages of this application are:

[0018] 1. Wide-range interference suppression: The combination of TVS diodes and current-limiting resistors can effectively suppress kV-level transient overvoltages (such as lightning strikes and ESD), the anti-reverse flow module avoids damage to the circuit by reverse power connection, the π-type filter circuit covers noise in the 100kHz-1GHz frequency band, meeting the high requirements of inertial navigation systems for power purity; the shielding cavity has a shielding effectiveness of ≥60dB to isolate external electromagnetic radiation and prevent noise from coupling to the signal path;

[0019] 2. Differential transmission reduces the impact of common-mode interference on the signal, and ESD protection devices provide fast clamping electrostatic discharge (response time < 1ns) to prevent electrostatic accumulation at the interface from damaging the back-end circuit; the combination of star topology and multi-point grounding reduces grounding impedance (especially at high frequencies), reduces ground bounce noise, and ensures low distortion and high stability of signal transmission.

[0020] 3. The independent daughterboard design achieves electrical and physical isolation between the protection circuit and the main control board, which facilitates modular debugging and replacement; the multi-level protection links filter energy impact and noise interference layer by layer, enabling the inertial navigation system to maintain stable operation in complex electromagnetic environments (such as industrial sites and vehicle scenarios), and significantly reducing the risk of positioning errors or system failures caused by abnormal power supply, electrostatic discharge or electromagnetic interference. Attached Figure Description

[0021] Figure 1 This is a functional block diagram of an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the antenna feeder circuit structure with signal ANT1_IN in an embodiment of this utility model;

[0023] Figure 3 This is a schematic diagram of the antenna feeder circuit structure with signal ANT2_IN in an embodiment of this utility model. Detailed Implementation

[0024] The following detailed description illustrates the specific implementation method:

[0025] The basic implementation examples are as follows: Figure 1 As shown: An inertial navigation system antenna feeder circuit includes an inertial navigation system and at least two antenna feeder circuits that use differential signal transmission. In contrast to the prior art where the antenna feeder lines are directly connected to the inertial navigation system using coaxial cables, the antenna feeder circuits in this application use differential transmission, such as shielded twisted pair cables, so that each antenna feeder circuit line exists independently.

[0026] Based on this, the antenna feeder circuit includes a power supply, a surge protection module, a reverse current protection module, an isolation module, an anti-static module, and a first capacitor. The surge protection module includes a TVS diode; the reverse current protection module includes a second capacitor, a third capacitor, a first inductor, and a second inductor; the anti-static module includes ESD protection devices; and the isolation module uses a single-layer shielded cavity with a shielding effectiveness ≥60dB. In its specific circuit structure, such as... Figure 2 and Figure 3 As shown, Figure 2 and Figure 3 It is based on Figure 1 The diagram shows two antenna feeder circuits using differential signal transmission. Based on different input signals, the two feeder circuits are divided into ANT1_IN and ANT2_IN. To better illustrate the connection relationships between the modules in the feeder circuit, ANT1_IN is used as an example. The power supply is represented by VIN. The power supply VIN is connected in series with a current-limiting resistor R1, which is then connected to the positive terminal of a TVS diode D1. The negative terminal of TVS diode D1 is connected to one end of a second capacitor C2, and the other end of the second capacitor C2 is grounded. The negative terminal of TVS diode D1 is also connected to a third capacitor C3, and the other end of the third capacitor C3 is grounded. The negative terminal of TVS diode D1 is also connected to... The first inductor L1 is connected to the first inductor L1, and the other end of the first inductor L1 is connected to the second inductor L2. The other end of the second inductor L2 is connected to the ESD protection device D2, and the other end of the ESD protection device D2 is grounded. At the same time, the second inductor L2 is connected to lead 1 of the metallized connector J1. The signal input of the antenna feeder circuit is connected to the ESD protection device D2 after being connected in series with the first capacitor C1. The ESD protection device D2 is also connected to lead 1 of the metallized connector J1. The metallized connector J1 is used to connect to the main control board. The connection lines of the antenna feeder circuit are wrapped in a single-layer shielded cavity, which reduces interference during signal transmission, improves signal integrity and transmission quality, and thus improves the navigation accuracy and stability of the system.

[0027] In this embodiment, in the above-mentioned circuit component connections, the TVS diode D1 can be of the SMBJ series, with a response time ≤1ns and the ability to absorb a surge current of 20kA; the first inductor L1 and the second inductor L2 adopt π-type filtering, covering the frequency band from 100kHz to 1GHz. At the same time, the first inductor L1 and the second inductor L2, together with the second capacitor C2 and the third capacitor C3, form an LC filter network to attenuate common-mode interference in long-distance transmission; the ESD protection device D2 adopts Bourns CDSOD323-T05C, which is connected in series at the signal line entrance to absorb electrostatic pulses; in addition to pin 1, the metallized connector also includes grounded pins 2, 3, 4, and 5.

[0028] Therefore, based on the circuit structure description of ANT1_IN above, the circuit structure of ANT2_IN is similar, and will not be repeated here.

[0029] Meanwhile, the aforementioned surge protection module, backflow prevention module, isolation module, and anti-static module are integrated on an independent daughterboard and connected to the external main control board via metallized connectors to reduce crosstalk. The internal components use a combination of star grounding and multi-point grounding to reduce common impedance coupling.

[0030] The above are merely embodiments of this utility model. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, based on the guidance provided in this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of this utility model. These should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An antenna feeder circuit for an inertial navigation system, characterized in that: The system includes an inertial navigation system and at least two antenna feeder circuits using differential signal transmission. Each antenna feeder circuit includes a power supply, a surge protection module, a backflow prevention module, an isolation module, and an anti-static module. The output of the inertial navigation system is connected to the input of the power supply. The output of the power supply is sequentially connected to the surge protection module, the backflow prevention module, the isolation module, and the anti-static module, forming a multi-level protection link. The multi-level protection link is integrated on an independent daughterboard and connected to the main control board via a metallized connector. The surge protection module is used to suppress voltage surges; the backflow prevention module is used to prevent current from flowing in the opposite direction; the isolation module is used for noise isolation; and the antistatic module is used to release static charge.

2. The inertial navigation system antenna feeder circuit according to claim 1, characterized in that: The surge protection module includes a TVS diode. The power supply is connected to the positive terminal of the TVS diode after being connected in series with a current-limiting resistor. The negative terminal of the TVS diode is connected to the backflow prevention module.

3. The inertial navigation system antenna feeder circuit according to claim 2, characterized in that: The backflow prevention module includes a second capacitor, a third capacitor, a first inductor, and a second inductor. One end of the second capacitor is connected to the negative terminal of the TVS diode, and the other end is grounded. One end of the third capacitor is connected to the negative terminal of the TVS diode, and the other end is grounded. One end of the first inductor is connected to the negative terminal of the TVS diode, and the other end is connected to the second inductor.

4. The inertial navigation system antenna feeder circuit according to claim 3, characterized in that: The other end of the second inductor is connected to a protection diode and simultaneously connected to the lead of the metallized connector; the other end of the protection diode is grounded.

5. The inertial navigation system antenna feeder circuit according to claim 3, characterized in that: The first and second inductors employ π-type filtering, covering a frequency band of 100kHz-1GHz.

6. The inertial navigation system antenna feeder circuit according to claim 4, characterized in that: The antenna feed circuit also includes a first capacitor, the anti-static module includes an ESD protection device, the other end of the second inductor is connected to the ESD protection device, and is also connected to the lead of the metallized connector; the signal input of the antenna feed circuit is connected to the ESD protection device after being connected in series with the first capacitor.

7. The inertial navigation system antenna feeder circuit according to claim 1, characterized in that: The isolation module is a single-layer shielded cavity, and the shielding effectiveness of the single-layer shielded cavity is ≥60dB.

8. The inertial navigation system antenna feeder circuit according to claim 4, characterized in that: The grounding adopts a combination of star grounding and multi-point grounding.

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