A high-stability satellite receiver

Abstract

This application discloses a high-stability satellite receiver, relating to the field of satellite navigation and positioning technology. It includes a receiver body and an external anti-interference antenna. The receiver body includes a printed circuit board assembly and a shielding cover. The printed circuit board assembly includes an interface processing unit, a baseband processing unit, a power management unit, and a radio frequency link unit. The shielding cover has multiple vertically arranged adaptive plates, each including side plates and partitions. The adaptive plates have three layers and a wave-shaped triangular sawtooth structure. When heated, the adaptive plates expand and compress the heat-generating elements of the printed circuit board assembly, enhancing heat dissipation. Simultaneously, they dynamically eliminate rigid gaps between the shielding cover and the printed circuit board assembly, preventing edge diffraction leakage. This achieves the technical effects of improved vibration stability, improved high-temperature adaptability, improved shielding performance, and improved received signal stability.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation and positioning technology, and in particular to a highly stable satellite receiver. Background Technology

[0002] The satellite receiver is a key device integrating the core technologies of the BeiDou Navigation Satellite System (BDS). Combined with SBAS satellite-based augmentation functions, it mainly performs core functions such as satellite signal acquisition, tracking, positioning, and short message delivery, and provides synchronous and asynchronous serial port output logic. As the terminal core of the satellite navigation system, it is irreplaceable in fields such as military command, disaster relief, and marine fisheries. It is not only the infrastructure to ensure accurate acquisition of location information, but also a key technological carrier for achieving all-weather, all-terrain communication and positioning, and is of strategic significance for improving the system's anti-interference capability and emergency response efficiency.

[0003] Existing shielding covers suffer from multiple integration defects, impacting the overall performance of the receiver. Specifically, fixed cavities typically separate circuit modules with rigid metal partitions, relying on physical isolation but unable to deform to adapt to changes in ambient temperature, resulting in insufficient high-temperature stability. Simultaneously, passive heat dissipation mechanisms rely solely on thermally conductive pads attached to bosses to transfer heat, limiting the heat dissipation area and failing to effectively suppress temperature rise, exacerbating vibration stability risks. Regarding shielding performance, static shielding is primarily designed for specific frequency bands, lacking flexibility to cope with high-frequency interference, affecting the stability of the received signal. Furthermore, assembly gaps are a significant issue; excessively large rigid gaps between the shielding cavity sidewalls and printed circuit board assemblies can cause edge diffraction leakage, further weakening shielding effectiveness and leading to inaccurate positioning. Summary of the Invention

[0004] This application provides a high-stability satellite receiver, which solves the technical problems of poor vibration stability, low temperature adaptability, limited shielding performance and poor received signal stability in the prior art, and achieves the technical effects of improved vibration stability, improved high temperature adaptability, improved shielding performance and improved received signal stability.

[0005] This application provides a high-stability satellite receiver, including a receiver body and an external anti-interference antenna, wherein the receiver body includes a printed circuit board assembly and a shielding cover; The printed circuit board assembly includes an interface processing unit, a baseband processing unit, a power management unit, and a radio frequency link unit; The shield has multiple vertically arranged adaptive plates, each including a side plate and a partition. The adaptive plate has three layers and a wave-shaped triangular sawtooth structure. When heated, it expands and squeezes the heat-generating elements of the printed circuit board assembly, thereby enhancing the heat dissipation effect. At the same time, it dynamically eliminates the rigid gap between the shield and the printed circuit board assembly, avoiding edge diffraction leakage.

[0006] Furthermore, the interface processing unit includes an FPGA chip, a clock circuit, a FLASH and a bus circuit, used to complete the interaction of external data; the baseband processing unit includes a baseband chip, a memory, a chip and a clock circuit, used to complete signal acquisition, tracking, PVT calculation, and short message packaging and spread spectrum.

[0007] Furthermore, the power management unit is used to power the baseband chip, RF chip, FPGA and peripheral circuits; the RF link unit includes a multiplexer, power divider, LNA low noise amplifier, SAW surface acoustic wave filter and RF chip, used to receive and transmit satellite signals; the RF chip is a four-receive-one-transmit multimode multifrequency chip, with four receiving channels and one transmitting channel, forming a multi-frequency integration.

[0008] Furthermore, the radio frequency port of the radio frequency link unit is fixed with a limiter to prevent damage from intentional or unintentional high-power input signals, thereby enabling it to resist power burnout and improving the environmental adaptability of the receiver body.

[0009] Furthermore, the receiver body has an external radio frequency interface fixed with a radio frequency lightning suppressor, which has indirect lightning protection capability and is used to protect the radio frequency transceiver equipment to operate reliably in complex environments.

[0010] Furthermore, the shielding cover includes a cover plate, a connecting block, a side plate, a cavity, and a partition plate; The cover plate, serving as a basic support component, is a rectangular metal plate structure. Four connecting blocks are provided and welded to the four corners of the cover plate, and fixed to the printed circuit board assembly with bolts. Four side plates are provided, with a wave-shaped structure, corresponding to the four end faces of the cover plate respectively. The cavity is formed by partitions to create a closed shielding area, separating the electronic components inside the printed circuit board assembly and avoiding electromagnetic interference.

[0011] Furthermore, both the side plate and the partition are provided with three layers, including an outer layer, a middle layer and an inner layer; The outer layer has a wavy, triangular, sawtooth structure made of metal, with an array of micropores etched inside for conductivity and high-frequency shielding. The middle layer is a sealed cavity structure that contracts and expands with temperature changes. The inner layer is made of silicone and contains silver particles. It is fixedly connected to the outer layer and allows the inner silicone to directly contact the heat-generating elements of the printed circuit board assembly when the middle layer expands due to heat, thus enhancing heat dissipation. At the same time, the silver particles and silicone layer fill the gaps between the elements, dynamically eliminating electromagnetic leakage gaps and improving the shielding effect.

[0012] Furthermore, the outer layer of the side plate is etched with a miniature piezoelectric sensor. The piezoelectric sensor is made of lead zirconate titanate (PZT) material, arranged in a matrix grid, and located in the high-frequency interference sensitive area of ​​the shield cavity sidewall. The piezoelectric sensor electrode is connected to the internal circuit of the shield through micro solder points to form a closed-loop detection path. The electromagnetic field coupling enables real-time detection of electromagnetic interference intensity in the 1-6 GHz frequency band.

[0013] Furthermore, the intermediate layer contains a fluid comprising strontium titanate nanofluid, n-octadecane, carbon nanotubes, and graphene oxide. The strontium titanate nanofluid, accounting for 60% of the total composition, is used to change its viscosity in response to the voltage generated by the piezoelectric sensor, achieving adaptive expansion due to interference intensity. The n-octadecane, accounting for 30% of the total composition, is used to drive temperature-adaptive deformation. The carbon nanotubes, accounting for 5% of the total composition, are used to enhance thermal conductivity and form an electromagnetic wave absorption network. The graphene oxide, accounting for 5% of the total composition, is used to stabilize and disperse the nanofluid and improve shear strength.

[0014] Furthermore, the intermediate layer has an elliptic spherical structure. The concentration of n-octadecane at the end of the long axis of the elliptic (low curvature region) increases from the center to the end, which is used to compensate for heat conduction hysteresis, accelerate phase change endothermic reaction, and improve the latent heat release rate. Its concentration at the midpoint of the short axis (high curvature region) decreases from the center to the end, which is used to reduce phase change volume expansion and avoid interfacial stress cracking. The concentration of strontium titanate at the end of the long axis (low curvature region) decreases from the center to the end to reduce the mechanical resistance to the phase transition; the concentration at the midpoint of the short axis (high curvature region) increases from the center to the midpoint of the short axis to enhance the local dielectric response and compensate for the electric field inhomogeneity caused by curvature.

[0015] One or more technical solutions provided in this application have at least the following technical effects or advantages: By employing wave-shaped side plates and partitions, the longitudinal vibration energy is converted into lateral deformation through the cantilever beam effect of corrugated pleats, thus dispersing and absorbing high-frequency vibration energy. A three-layer composite adaptive structure is incorporated to adaptively adjust to environmental conditions (temperature, vibration, and strong interference). Real-time monitoring by piezoelectric sensors and the distribution design of n-octadecane and strontium titanate prevent stress cracking and enhance dielectric response, further improving electromagnetic shielding effectiveness. Dual-layer protection with a limiter and lightning suppressor provides the receiver body with first-level protection against high-power burn-out and second-level protection against lightning pulses, further improving the stability of the satellite receiver's received signal and increasing positioning accuracy. This effectively solves the technical problems of poor vibration stability, low temperature adaptability, limited shielding performance, and poor received signal stability in existing technologies, achieving improved vibration stability, high-temperature adaptability, shielding performance, and received signal stability. Attached Figure Description

[0016] Figure 1 This is an exploded view of the structure of a high-stability satellite receiver according to the present invention.

[0017] Figure 2 This is a schematic diagram of the printed circuit board assembly of a high-stability satellite receiver according to the present invention.

[0018] Figure 3 This is a three-dimensional structural diagram of the shielding cover for a high-stability satellite receiver according to the present invention.

[0019] Figure 4 This is a schematic diagram of the side structure of the shielding cover of a high-stability satellite receiver according to the present invention.

[0020] Figure 5 This is a bottom view of the shielding cover for a high-stability satellite receiver according to the present invention.

[0021] Figure 6 This invention relates to a high-stability satellite receiver. Figure 5 Full sectional view along the AA direction.

[0022] Figure 7 This invention relates to a high-stability satellite receiver. Figure 6 A magnified view of a portion of point B in the middle.

[0023] Figure 8 This invention relates to a high-stability satellite receiver. Figure 6 A magnified view of a portion of point C in the middle.

[0024] Figure 9 This is a schematic diagram of a high-stability satellite receiver according to the present invention.

[0025] Figure 10 This is a technical roadmap for a high-stability satellite receiver according to the present invention.

[0026] Figure 11 This is a block diagram of the radio frequency link unit of a high-stability satellite receiver according to the present invention.

[0027] Figure 12 This is a chart showing the selection parameters for the power divider of a high-stability satellite receiver according to the present invention.

[0028] Figure 13 This is a chart showing the selection parameters for a SAW filter in a high-stability satellite receiver according to the present invention.

[0029] Figure 14 This is a block diagram of the baseband processing unit of a high-stability satellite receiver according to the present invention.

[0030] Figure 15This is a block diagram of the interface processing unit of a high-stability satellite receiver according to the present invention.

[0031] Figure 16 This is a lightning protection circuit diagram for the radio frequency interface of a high-stability satellite receiver according to the present invention.

[0032] Figure 17 This is a short-circuit protection circuit diagram for a high-stability satellite receiver according to the present invention.

[0033] In the diagram: 100, receiver body; 110, printed circuit board assembly; 111, interface processing unit; 112, baseband processing unit; 113, power management unit; 114, RF link unit; 115, limiter; 200, shielding cover; 201, outer layer; 202, middle layer; 203, inner layer; 210, cover plate; 220, connecting block; 230, side plate; 240, cavity; 250, partition plate; 260, piezoelectric sensor; 261, fluid. Detailed Implementation

[0034] To facilitate understanding of the present invention, a more complete description of this application will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention may be more thorough and complete.

[0035] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] Please see Figure 1This is an exploded view of the structure of a high-stability satellite receiver according to the present invention. The high-stability satellite receiver of this application employs a wave-shaped side plate 230 and partition 250, which converts longitudinal vibration energy into lateral deformation through the cantilever beam effect of the corrugated pleats, thus dispersing and absorbing high-frequency vibration energy. A three-layer composite adaptive structure is set up to adaptively adjust to the environment (temperature, vibration, and strong interference conditions). The piezoelectric sensor 260, along with n-octadecane and strontium titanate distributed according to curvature, avoids stress cracking and enhances dielectric response, further improving electromagnetic shielding effectiveness. Through the dual protection of a limiter 115 and a lightning suppressor, the receiver body 100 is provided with a first level of protection against high-power burn-out and a second level of protection against lightning pulses, further improving the stability of the received signal. This achieves the technical effects of improved vibration stability, improved high-temperature adaptability, improved shielding performance, and improved received signal stability.

[0038] Example 1: As Figures 1 to 8 As shown, this application discloses a high-stability satellite receiver, which includes a receiver body 100 and an external anti-interference antenna. The receiver body 100 includes a printed circuit board assembly 110 and a shielding cover 200. The printed circuit board assembly 110 includes an interface processing unit 111, a baseband processing unit 112, a power management unit 113, and a radio frequency link unit 114; The shield 200 has multiple vertically arranged adaptive plates, each including a side plate 230 and a partition plate 250. The adaptive plate has three layers and a wave-shaped triangular sawtooth structure. When heated, it expands and squeezes the heating element of the printed circuit board assembly 110, thereby enhancing the heat dissipation effect. At the same time, it dynamically eliminates the rigid gap between the shield 200 and the printed circuit board assembly 110, avoiding edge diffraction leakage.

[0039] The interface processing unit 111 includes an FPGA chip, a clock circuit, a FLASH and a bus circuit, used to complete the interaction of external data; including data relay, arbitration, distribution processing, self-testing, software loading and debugging, observation storage, satellite data indication, and packaging and processing data according to the required communication format; the baseband processing unit 112 includes a baseband chip, a memory, a chip and a clock circuit, used to complete signal acquisition, tracking, PVT calculation, and packaging and spreading of short message information.

[0040] The power management unit 113 supplies power to the baseband chip, RF chip, FPGA, and peripheral circuits. The RF link unit 114 includes a multiplexer, power divider, LNA low-noise amplifier, SAW surface acoustic wave filter, and RF chip for receiving and transmitting satellite signals. The RF chip is a four-receive-one-transmit multi-mode multi-frequency chip with four receive channels and one transmit channel, forming a multi-frequency integration. This enhances the system's flexibility and scalability, reduces hardware costs, and minimizes equipment maintenance workload.

[0041] The radio frequency link unit 114 has a fixed radio frequency limiter 115 at its radio frequency port to prevent damage from intentional or unintentional high-power input signals, thus enabling it to resist power burnout and improving the environmental adaptability of the receiver body 100. The external radio frequency interface of the receiver body 100 is equipped with a radio frequency lightning suppressor, which has indirect lightning protection capability and is used to protect the radio frequency transceiver equipment to operate reliably in complex environments.

[0042] When subjected to momentary lightning waveform effects, performance temporarily degrades, but recovers automatically once the interference disappears. Simultaneously, the external antenna is fed in a straight-through manner; it will not be damaged when the RF interface is short-circuited, and will resume normal function once the short-circuit condition disappears. Furthermore, the receiver body 100 integrates RF and digital circuits on its board. To ensure reliable operation of the RF circuits, the RF circuit ground and digital circuit ground are isolated through a single-point grounding design.

[0043] The receiver equipment described in this application typically includes a receiver body 100 and an anti-interference antenna. It is capable of receiving civilian signals such as B1C and B3I satellites, and features three independent positioning modes: BDS B3 / B1 dual-frequency, BDS B3 single-frequency, and BDS B1 single-frequency. It supports SBAS (Satellite-Based Augmentation System) functionality. The receiver equipment can output real-time information such as the carrier's position, speed, and time, and can receive inertial information from the inertial navigation system to improve its dynamic performance, suppress the impact of noise on accuracy, and enhance anti-interference capabilities. The receiver equipment is capable of resisting six-directional suppression interference, has anti-spoofing capabilities, and supports RDSS (Satellite Radio Determination Service) regional short message and global short message communication functions.

[0044] like Figure 1 , Figures 3 to 8 As shown, the shielding cover 200 includes a cover plate 210, a connecting block 220, a side plate 230, a cavity 240, and a partition plate 250; The cover plate 210 serves as a basic support component and is a rectangular metal plate structure. Four connecting blocks 220 are provided and welded to the four corners of the cover plate 210, and fixed to the printed circuit board assembly 110 by bolts. Four side plates 230 are provided and have a wave-shaped structure, corresponding to the four end faces of the cover plate 210 respectively. The cavity 240 is formed by partitions 250 and is used to form a closed shielding area to separate the electronic components inside the printed circuit board assembly 110 and avoid electromagnetic interference.

[0045] like Figures 6 to 8 As shown, both the side plate 230 and the partition plate 250 are provided with three layers, including an outer layer 201, a middle layer 202 and an inner layer 203; The outer layer 201 has a wavy, triangular, sawtooth structure made of metal, with an array of micropores etched inside for conductivity and high-frequency shielding. The middle layer 202 is a sealed cavity structure that contracts and expands with temperature changes. The inner layer 203 is made of silicone and contains silver particles. It is fixedly connected to the outer layer 201 and allows the silicone in the inner layer 203 to directly contact the heating elements of the printed circuit board assembly 110 when the middle layer 202 expands due to heat, thus enhancing heat dissipation. Simultaneously, the silver particles and silicone layer fill the gaps between the elements, dynamically eliminating electromagnetic leakage gaps and improving the shielding effect. The outer layer 201 is made of beryllium copper alloy.

[0046] This application, by setting a wave-shaped side plate 230, can convert longitudinal vibration energy into lateral deformation, disperse and absorb displacement energy during high-frequency vibration (≥15G), improve vibration stability, extend the heat dissipation surface area through the wave structure extension, improve heat dissipation capacity, extend the electromagnetic wave propagation path, increase diffraction loss, and improve high-frequency shielding effectiveness.

[0047] By employing a three-layer composite structure, the middle layer 202 acts as a sealed cavity, and its thermal expansion can push the inner silicone layer 203 containing silver particles to tightly adhere to the heating element of the printed circuit board assembly 110, filling the gaps between elements, eliminating rigid gaps in the assembly, avoiding edge diffraction leakage, and dynamically eliminating electromagnetic leakage gaps. At the same time, the micro-pore array (etched into the metal layer) of the outer layer 201 opens at high temperatures to form airflow channels, enhancing convective heat dissipation. At high temperatures, the fluid 261 (n-octadecane) in the middle layer 202 undergoes a phase change and expands (volume increases), squeezing the silicone of the inner layer 203 to directly contact the chip, further improving heat dissipation efficiency. When at low temperatures, the middle layer 202 contracts, and the micropores close to reduce heat loss, achieving temperature-adaptive deformation.

[0048] like Figure 8The diagram shows a partial enlarged cross-sectional view of partition 250. Partition 250 consists of two partitions 250 placed in a mirror image. The outer layers 201 of the two partitions 250 are fixed to form an integral corrugated metal plate. The inner layers 203 on both sides expand to the sides in the expanded state, contacting the components on both sides and reducing the rigid gap between them.

[0049] like Figures 6 to 8 As shown, the outer layer 201 of the side plate 230 is etched with a miniature piezoelectric sensor 260. The piezoelectric sensor 260 is made of lead zirconate titanate (PZT) material, arranged in a matrix grid, and located in the high-frequency interference sensitive area of ​​the side wall of the cavity 240 of the shield 200. The electrodes of the piezoelectric sensor 260 are connected to the internal circuit of the shield 200 through micro solder joints to form a closed-loop detection path. The electromagnetic field coupling is used to realize the real-time detection of electromagnetic interference intensity in the 1-6 GHz frequency band.

[0050] The intermediate layer 202 contains a fluid 261, which includes strontium titanate nanofluid, n-octadecane, carbon nanotubes, and graphene oxide. The strontium titanate nanofluid, accounting for 60% of the total composition, is used to change its viscosity in response to the voltage generated by the piezoelectric sensor 260, thereby achieving adaptive expansion due to interference intensity. The n-octadecane accounts for 30% of the total composition and is used to drive temperature-adaptive deformation. The carbon nanotubes account for 5% of the total composition and are used to enhance thermal conductivity and form an electromagnetic wave absorption network. The graphene oxide accounts for 5% of the total composition and is used to stabilize and disperse the nanofluid and improve shear strength.

[0051] This application utilizes a piezoelectric sensor 260 and an intelligent fluid interference response mechanism. The piezoelectric sensor 260 (made of PZT material) detects electromagnetic interference in the 1-6GHz range in real time, generating a voltage signal to drive the strontium titanate nanofluid to change its viscosity. When strong interference is detected (such as 5GHz radar), the fluid viscosity of the fluid 261 decreases, the intermediate layer 202 expands rapidly, eliminating rigid physical gaps and ensuring shielding effectiveness. Correspondingly, under high-temperature and strong interference conditions, the phase change expansion of n-octadecane (PCM) and the dielectric fluid response are superimposed, simultaneously optimizing heat dissipation and shielding.

[0052] Furthermore, the intermediate layer 202 is an elliptical spherical structure. The concentration of n-octadecane at the end of the long axis of the ellipse (low curvature region) increases from the center to the end, which is used to compensate for heat conduction hysteresis, accelerate phase change endothermic reaction, and improve the latent heat release rate. Its concentration at the midpoint of the short axis (high curvature region) decreases from the center to the end, which is used to reduce phase change volume expansion and avoid interfacial stress cracking. The concentration of strontium titanate at the end of the long axis (low curvature region) decreases from the center to the end to reduce the mechanical resistance to the phase transition; the concentration at the midpoint of the short axis (high curvature region) increases from the center to the midpoint of the short axis to enhance the local dielectric response and compensate for the electric field inhomogeneity caused by curvature.

[0053] This application optimizes the gradient concentration distribution of n-octadecane (PCM) and strontium titanate in an elliptical spheroid, namely, the gradient distribution of fluid 261 formulation (the concentration of n-octadecane / strontium titanate is adjusted according to the curvature of the elliptical spheroid). By precisely adapting to the geometric curvature characteristics, it can avoid interfacial stress cracking, improve dielectric response, and achieve synergistic optimization of thermal management and electromagnetic control.

[0054] The piezoelectric sensor 260 is used for real-time detection of 1-6GHz electromagnetic interference, and is preferably a TDK PSF series piezoelectric thin film sensor; both are existing technologies and will not be described in detail here.

[0055] Overall, the receiver body 100, through efficient heat dissipation and electromagnetic shielding design (such as the shielding cover 200), ensures stable operation in an environment of -55℃ to +85℃, with a power consumption of ≤8W. Its working principle is as follows: after the satellite signal is down-converted by the radio frequency link (i.e., radio frequency link unit 114), the baseband processing unit 112 calculates the positioning information, and then the interface processing unit 111 outputs the position, velocity, and time data. The detailed principle is as follows: like Figure 9 The diagram shows the working principle of the receiver equipment. The equipment mainly completes satellite signal acquisition, tracking, positioning, and short message processing. It supports multiple positioning modes such as BDSB1 / B3 dual-frequency and has anti-interference and anti-spoofing capabilities. Its working principle includes the following key parts: The radio frequency link unit 114 is responsible for receiving satellite signals such as B1 / L1 / E1, B3, S, and B2b. It processes the signals through components such as limiter 115, multiplexer, LNA low-noise amplifier, and SAW filter to achieve burn-out resistance (resisting 30dBm power) and transmit / receive link optimization; The baseband processing unit 112 consists of a baseband chip, memory (such as 128MbitSPIFLASH and 1GbDDR3), and clock circuit. It completes signal acquisition, tracking, PVT calculation (position, velocity, time), and short message packet spreading; The interface processing unit 111 is based on an FPGA chip to process external data interaction, including data relay, arbitration, and communication format packaging, and supports self-testing and software upgrades.

[0056] like Figure 10The diagram shows the overall technical roadmap of the satellite receiver. The receiver is the core strategy of being embedded in the inertial navigation system as an SRU (Standard Replacement Unit). The integration is optimized using an adaptive improvement method. Its key elements include: (1) Hardware interface adaptation: Design compatible hardware interfaces for the physical connection requirements of various types of inertial navigation computers to ensure seamless connection between the receiver and the inertial navigation system and support signal transmission and power management; (2) Software protocol compatibility: Optimize the software interface to realize the data interaction protocol with the inertial navigation computer (such as serial port output logic) to ensure the synchronous processing of real-time position, speed and time information; (3) Improved design strategy: Adopt modular design to reduce system conflicts, improve anti-interference ability, and enhance stability in extreme environments (-55℃~+85℃) through heat dissipation and electromagnetic shielding (such as shielding cover 200); aiming to reduce integration complexity, improve dynamic performance and reliability, and support BDS dual-frequency positioning and short message function.

[0057] The satellite receiver hardware scheme includes an RF link unit 114, a baseband processing unit 112, an interface processing unit 111, and a power supply unit (i.e., a power management unit 113).

[0058] (1) Radio frequency link unit 114 like Figure 11 The diagram shown is a block diagram of the radio frequency link unit 114. The block diagram of the radio frequency link unit 114 illustrates in detail the signal processing flow of the receiver radio frequency link. The modular design ensures reliable transmission and reception of multi-frequency satellite signals.

[0059] Its core structure includes: a receiving link, a transmitting link, and an integrated radio frequency chip.

[0060] Receiver Link: Satellite signals (such as B1 / L1 / E1, B3, S, B2b) pass sequentially through limiter 115 (resistant to 30dBm power burnout), multiplexer, LNA low-noise amplifier, and power divider, before being distributed to the RX1~RX4 channels of the RF chip for down-conversion. Power divider selection (such as...) Figure 12 Ensures low insertion loss (≤0.4dB) and covers the 1~2.9GHz frequency band.

[0061] Transmit link: Signals Lf1 to Lf4 are output from the TX channel of the RF chip, amplified by a SAW filter (center frequency 1618MHz, insertion loss ≤1.8dB) and an LNA, and then output to the antenna via a multiplexer. SAW filter selection (e.g.) Figure 13 Optimize bandwidth and frequency stability.

[0062] RF chip integration: Employing a four-receiver-one-transmitter multimode chip, supporting the 1.15–2.5 GHz frequency band, and integrating LNA, mixer, etc., to achieve efficient signal conversion and anti-interference. The overall design has been verified through simulation and meets the requirements for dynamic performance and extreme environments (-55℃ to +85℃).

[0063] The radio frequency link unit 114 consists of a limiter 115, a multiplexer, a power divider, an LNA low-noise amplifier, a SAW surface acoustic wave filter, and radio frequency chips. It is capable of receiving B1 / L1 / E1, B3, S, and B2b satellite signals and transmitting Lf1 to Lf4 satellite signals, requiring the selection of radio frequency chips that can cover the aforementioned frequency points.

[0064] The RF chip is a four-receiver-one-transmitter multi-mode multi-frequency RF chip, featuring four receive channels and one transmit channel. Its RNSS receiving frequency covers 1.15GHz–1.65GHz, its RDSS receiving frequency covers 2.483GHz–2.5GHz, and its transmit frequency covers 1.61GHz–1.68GHz. This chip also integrates a complete receiver link including a low-noise amplifier, down-conversion mixer, filter, programmable amplifier, analog-to-digital converter, and phase-locked loop, as well as a complete transmitter link including a filter, up-conversion mixer, and power preamplifier. A single chip can simultaneously support navigation and communication functions, possessing RN+RD RF one-line communication capabilities. It offers advantages in multi-frequency integration, enhancing system flexibility and scalability, reducing hardware costs, and minimizing equipment maintenance workload.

[0065] Furthermore, the RF link unit 114 incorporates RF port burn-out protection and transceiver link design. Burn-out protection is achieved by adding a limiter 115 to the RF port, preventing intentional or unintentional damage to the receiver from high-power input signals, and providing resistance to 30dBm power burn-out. The transceiver link design involves down-converting the BDSB1 / GPSL1 / GalileoE1, BDSB3, BDSS, and B2b signals to the RX1, RX2, RX3, and RX4 channels of the RF chip after passing through the limiter 115, multiplexer, LNA low-noise amplifier, and power divider in the receiving link. The L-frequency signal of the transmitting link is output from the TX channel of the RF chip, passes through a SAW filter, LNA low-noise amplifier, and multiplexer, and is then output to the antenna for transmission. Based on simulation design, the selected component parameters, taking the power divider and SAW filter as examples, are described in the following reference. Figure 12 and Figure 13 .

[0066] (2) Baseband processing unit 112 like Figure 14The diagram shows a block diagram of the baseband processing unit 112. This block diagram illustrates the architecture of the receiver's core signal processing module, employing a modular design to achieve efficient satellite signal processing. The baseband chip in the baseband processing unit 112 integrates a dual-core high-performance processor, supporting up to 12 digital intermediate frequency (IF) inputs or 8 analog IF inputs. As the program memory for the baseband chip, it is externally connected to a 128 Mbit SPI FLASH memory, operating at 1.8V and a clock frequency of 133 MHz. This chip is of high quality and maturity, with a temperature range of -55℃ to +125℃, meeting the requirements for use. Simultaneously, to increase system memory, following the recommended usage of the baseband chip, an external 1 Gb DDR3 memory is connected, operating at 1.5V and a clock frequency of 800 MHz. This chip is of high quality and maturity, with a temperature range of -55℃ to +125℃, meeting the requirements for use in this application.

[0067] In addition, the clock circuit has two paths. One path uses a temperature-compensated crystal oscillator to generate a 10MHz frequency, which enhances the load-driving capability through the clock driver chip and provides a reference frequency for the RF chip. The other path uses a resonator to generate a 32.768kHz frequency, which provides a reference frequency for the RTC inside the baseband chip. The temperature-compensated crystal oscillator used in this application has a wide temperature range, high frequency stability, small size, light weight, strong vibration resistance, and is easy to use.

[0068] (3) Interface processing unit 111 like Figure 15 The diagram shows the interface processing unit 111, illustrating the core architecture for external data interaction of the receiver. Its design focuses on efficient data management and system control. The interface processing unit 111 consists of an FPGA chip, a clock circuit, FLASH memory, and a bus circuit. The FPGA chip parses, packages, and distributes data according to the required communication format. It controls the online upgrade of the baseband chip and FPGA program based on instructions, and performs internal control and scheduling based on discrete signals. A 128M-bit high-reliability NOR FLASH memory A is preferred as the FPGA program memory. This FLASH memory has low power consumption, a maximum current of 50mA, a read frequency of 50MHz, can be erased and written up to 10,000 times, and has a data retention time of up to 10 years. The non-volatile memory chip uses SPI FLASH memory to store self-test results, receiver positioning results, and operating status information. Based on a storage capacity of 2000 bytes per second, it can retain 74.5 hours of data without repetition. The stored results can be downloaded through the detection port as a basis for fault diagnosis.

[0069] The FLASH has a temperature range of -55℃ to 125℃, a storage capacity of 512Mb, a maximum erase / write cycle of 100,000, and a data retention time of up to 20 years, which meets the requirements of this application. The clock circuit consists of a temperature-compensated crystal oscillator and a clock driver chip. The crystal oscillator generates a 20MHz frequency to provide a reference frequency for the FPGA chip. Preferably, the temperature-compensated crystal oscillator and the clock driver chip are domestically produced, and their temperature ranges both reach -55℃ to 105℃.

[0070] The clock circuit consists of a temperature-compensated crystal oscillator and a clock driver chip. The crystal oscillator generates a 20MHz frequency to provide a reference frequency for the FPGA chip. This application uses domestically produced temperature-compensated crystal oscillators and clock driver chips, both of which have a temperature range of -55℃ to 105℃, meeting the requirements of the operating environment.

[0071] (3) Power supply unit (i.e., power management unit 113) The power management unit 113 is used to power the baseband chip, RF chip, FPGA and peripheral circuits. The 5V power supply of the receiver body 100 is provided by the inertial navigation or attitude control system, and is converted into voltages such as 3.3V, 1.8V and 1.0V by the power chip. The selected power chip has a temperature range of -55℃ to 125℃. The 3.3V timekeeping power supply is supplied to the receiver by the inertial navigation or attitude control system, and is filtered by the receiver to power the RTC chip.

[0072] There are three main types of circuit protection for satellite receivers: lightning protection, short circuit protection, and ground isolation.

[0073] 1. Lightning protection like Figure 16 The diagram shown is a block diagram of the RF interface lightning protection circuit. The receiver's RF interface has indirect lightning protection capability. When subjected to instantaneous lightning waveform effects, its performance temporarily degrades, but it can recover automatically after the interference environment disappears. The experimental level is not lower than level 3. An RF lightning suppressor is preferably used to protect the RF transceiver equipment and ensure reliable operation in complex environments. This satellite receiver covers all frequency points specified in this application, such as... Figure 16 The diagram shown is a lightning protection circuit diagram for an RF interface. Its performance specifications are as follows: VSWR: not greater than 1.5:1; Insertion loss: not greater than 0.5dB; Maximum power: not greater than 20W; Power supply: 5V; Lightning protection level: A3.

[0074] 2. Short circuit protection like Figure 17The diagram shown is a block diagram of a short-circuit protection circuit. The antenna is fed in a straight-through state. When a short circuit occurs at the RF interface, the product will not be damaged, and normal function will be restored when the short circuit disappears. When a short-circuit protection chip is selected, its main performance characteristics are as follows: Input range: 2.5V~5.5V; On-resistance: 45mΩ; Maximum current: 3A; Adjustable current limit; Self-resetting thermal protection function.

[0075] 3. Ground isolation The receiver board integrates radio frequency (RF) and digital circuits. To ensure the reliable operation of the RF circuits, the RF circuit ground and the digital circuit ground are connected by a single-point grounding design.

[0076] The receiver consists of a printed circuit board, components, a shielding cover 200, connectors, and other parts, with the following weights: printed circuit board 15g, components 21g, shielding cover 35g, connectors 5g, and other parts 2g. The satellite receiver weighs 78g, meeting the technical requirement of a receiver weight ≤200g. The physical characteristics of the satellite receiver include: weight ≤0.2kg; power supply voltage: 5VDC±5%; power consumption: ≤8W (all-state). The anti-interference antenna has a power supply voltage range of 18VDC~32VDC; its power consumption is no greater than 70W (non-transmitting state) and no greater than 100W (transmitting state). Temperature adaptability requirements: its operating temperature is maintained at -55℃~+85℃ (receiver module) and -55℃~+70℃ (anti-interference antenna); its storage temperature is maintained at -55℃~+85℃ (receiver module) and -55℃~+70℃ (anti-interference antenna).

[0077] The power consumption of the receiver under all 5V power supply conditions is analyzed and predicted, including: baseband chip + DDR + FLASH (steady-state: 0.5W, peak: 0.8W), chip 0.5W, FPGA + FLASH 3.5W, and RF chip 1W. Assuming a power conversion efficiency of 85%, the receiver's steady-state power consumption is 5.5 / 0.85 = 6.5W, and the peak power consumption is 5.8W / 0.85 = 6.8W, which meets the power consumption requirement of ≤8W (all conditions).

[0078] In actual operation, the steps of this embodiment are as follows: Step 1: Environmental Parameter Sensing and Signal Reception First, the external anti-interference antenna captures satellite signals such as B1 / L1 / E1, B3, S, and B2b. The signals are processed by the radio frequency link unit 114: sequentially passing through the limiter 115 (burn-out protection), multiplexer, LNA (low-noise amplifier), and SAW (surface acoustic wave) filter, and finally down-converted by the radio frequency chip. The piezoelectric sensor 260 in the side plate 230 of the shield 200 detects electromagnetic interference in the 1-6GHz frequency band in real time. When strong interference is detected, such as a 5GHz radar pulse, the strong interference triggers the piezoelectric effect and generates a voltage signal. The stronger the interference, the higher the voltage. Step 2: Adaptive Shielding and Thermal Response When the ambient temperature is greater than 28°C, the octadecane PCM in the intermediate layer 202 melts into a liquid state and expands in volume by 1.5 times. This expansion pushes the silver-containing silicone in the inner layer 203 to tightly adhere to the heating element (such as the baseband chip) of the printed circuit board assembly 110, eliminating assembly gaps. The piezoelectric voltage acts on the strontium titanate nanofluid in the intermediate layer 202, reducing its viscosity, enhancing fluid flow, accelerating PCM diffusion, and increasing the airbag expansion rate. The shielding cover 200 can quickly adhere to the printed circuit board assembly 110, allowing it to flexibly adapt to shielding requirements under strong interference and dynamically eliminate electromagnetic leakage. At the same time, at high temperatures, the outer 201 micro-pore array expands the beryllium copper alloy and deforms, forming airflow channels. Hot air escapes through the micropores, creating a chimney effect and improving heat dissipation efficiency. Step 3: Signal Processing and Positioning Output The down-converted signal is transmitted to the baseband processing unit 112, where the baseband chip performs signal acquisition, tracking, and PVT calculation of position / velocity / time, and synchronously processes short message information packaging and spread spectrum; the FPGA chip of the interface processing unit 111 packages the calculated data and outputs position, velocity, and time information through the serial port; Step 4: Adaptation to Extreme Environments When in a low-temperature shrinkage mechanism state, i.e., when the ambient temperature is <28℃, n-octadecane (PCM) solidifies and shrinks, restoring the thickness of the intermediate layer 202 to its initial value, and closing the micropores to reduce heat loss. At this time, the piezoelectric sensor 260 adjusts the fluid viscosity to suppress excessive shrinkage and maintain the basic shielding effectiveness. Simultaneously, under high-frequency vibration ≥15G, the corrugated side plate 230 absorbs longitudinal vibration energy through corrugations and pleats, converting it into lateral deformation to ensure the stability of the printed circuit board assembly 110. Step 5: Linking Protection Mechanisms The RF port lightning suppressor protects against indirect lightning strikes and ensures that the device recovers automatically after the interference disappears. The short-circuit protection chip triggers current limiting when the RF interface is abnormal and automatically resets after the fault is cleared.

[0079] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages: It effectively solves the technical problems of poor vibration stability, low temperature adaptability, limited shielding performance and poor signal reception stability in the existing technology, and achieves the technical effects of improved vibration stability, improved high temperature adaptability, improved shielding performance and improved signal reception stability.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-stability satellite receiver, characterized in that, It includes a receiver body (100) and an external anti-interference antenna, wherein the receiver body (100) includes a printed circuit board assembly (110) and a shielding cover (200). The printed circuit board assembly (110) includes an interface processing unit (111), a baseband processing unit (112), a power management unit (113), and a radio frequency link unit (114). The shield (200) has multiple vertically arranged adaptive plates, each including a side plate (230) and a partition (250). The adaptive plate has three layers and a wave-shaped triangular sawtooth structure. When heated, it expands and squeezes the heating element of the printed circuit board assembly (110), thereby enhancing the heat dissipation effect. At the same time, it dynamically eliminates the rigid gap between the shield (200) and the printed circuit board assembly (110) to avoid edge diffraction leakage. The side plate (230) and the partition (250) are each provided with three layers, including an outer layer (201), a middle layer (202) and an inner layer (203). The outer layer (201) has a wavy triangular sawtooth structure, is made of metal, and has a micro-pore array etched inside for conductivity and high-frequency shielding; the middle layer (202) has a sealed cavity structure that contracts and expands with temperature changes; the inner layer (203) is made of silicone and contains silver particles, and is fixedly connected to the outer layer (201) for thermal expansion of the middle layer (202), so that the silicone of the inner layer (203) directly contacts the heat-generating element of the printed circuit board assembly (110) under the expansion of the middle layer (202), thereby enhancing heat dissipation. At the same time, the silver particles-silicone layer fills the gaps between the elements, thereby dynamically eliminating electromagnetic leakage gaps and improving the shielding effect. The outer layer (201) of the side plate (230) is etched with a miniature piezoelectric sensor (260). The piezoelectric sensor (260) is made of lead zirconate titanate (PZT) material, arranged in a matrix grid, and located in the high-frequency interference sensitive area of ​​the side wall of the cavity (240) of the shield (200). The electrodes of the piezoelectric sensor (260) are connected to the internal circuit of the shield (200) through micro solder joints to form a closed-loop detection path. The electromagnetic field coupling is used to realize the real-time detection of electromagnetic interference intensity in the 1-6GHz frequency band. The intermediate layer (202) contains a fluid (261), which includes strontium titanate nanofluid, n-octadecane, carbon nanotubes, and graphene oxide. The strontium titanate nanofluid is used to change its viscosity in response to the voltage generated by the piezoelectric sensor (260) to achieve adaptive expansion of interference intensity, and accounts for 60% of the total composition. The n-octadecane accounts for 30% of the total composition and is used to drive temperature-adaptive deformation. The carbon nanotubes account for 5% of the total composition and are used to enhance thermal conductivity and form an electromagnetic wave absorption network. The graphene oxide accounts for 5% of the total composition and is used to stabilize and disperse the nanofluid and improve shear strength. The intermediate layer (202) is an ellipsoidal spherical structure. The concentration of n-octadecane at the end of the long axis of the ellipsoid increases from the center to the end, which is used to compensate for heat conduction hysteresis, accelerate phase change endothermic reaction, and improve the latent heat release rate. Its concentration at the midpoint of the short axis decreases from the center to the endpoint, which is used to reduce phase transformation volume expansion and avoid interfacial stress cracking. The concentration of strontium titanate at the end of the long axis decreases from the center to the end, which is used to reduce the mechanical resistance to the phase transition; the concentration at the midpoint of the short axis increases from the center to the midpoint of the short axis, which is used to enhance the local dielectric response and compensate for the electric field inhomogeneity caused by curvature.

2. A high-stability satellite receiver as described in claim 1, characterized in that, The interface processing unit (111) includes an FPGA chip, a clock circuit, a FLASH and a bus circuit, used to complete the interaction of external data; the baseband processing unit (112) includes a baseband chip, a memory, a chip and a clock circuit, used to complete the acquisition, tracking and PVT calculation of signals, and to complete the packaging and spread spectrum of short message information.

3. A high-stability satellite receiver as described in claim 1, characterized in that, The power management unit (113) is used to power the baseband chip, RF chip, FPGA and peripheral circuits; the RF link unit (114) includes a multiplexer, power divider, LNA low noise amplifier, SAW surface acoustic wave filter and RF chip, used to receive and transmit satellite signals; the RF chip is a four-receive-one-transmit multimode multifrequency chip with four receiving channels and one transmitting channel, forming a multi-frequency integration.

4. A high-stability satellite receiver as described in claim 1, characterized in that, The radio frequency link unit (114) has a fixed limiter (115) at its radio frequency port to prevent damage from intentional or unintentional high-power input signals, thereby enabling it to resist power burnout and improving the environmental adaptability of the receiver body (100).

5. A high-stability satellite receiver as described in claim 1, characterized in that, The receiver body (100) has an external radio frequency interface fixed with a radio frequency lightning suppressor, which has indirect lightning protection capability and is used to protect the radio frequency transceiver equipment to operate reliably in complex environments.

6. A high-stability satellite receiver as described in claim 1, characterized in that, The shielding cover (200) includes a cover plate (210), a connecting block (220), a side plate (230), a cavity (240), and a partition plate (250); The cover plate (210) serves as a basic support component and is a rectangular metal plate structure. Four connecting blocks (220) are provided and welded to the four corners of the cover plate (210) and fixed to the printed circuit board assembly (110) by bolts. Four side plates (230) are provided and are of a wave-shaped structure, corresponding to the four end faces of the cover plate (210) respectively. The cavity (240) is formed by partitions (250) and is used to form a closed shielding area to separate the electronic components in the printed circuit board assembly (110) and avoid electromagnetic interference.

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