High-stability satellite receiver

Abstract

The invention discloses a high-stability satellite receiver, and relates to the technical field of satellite navigation and positioning, the high-stability satellite receiver comprises a receiver body and an external anti-interference antenna, and the receiver body comprises a printed board assembly and a shielding cover; the printed board assembly comprises an interface processing unit, a baseband processing unit, a power management unit and a radio frequency link unit; the shielding cover is provided with a plurality of self-adaptive plates which are vertically arranged, each self-adaptive plate comprises a side plate and a partition plate, each self-adaptive plate is provided with three layers and is of a wave-shaped triangular sawtooth structure, the self-adaptive plates are expanded by being heated and extrude heating elements of the printed board assembly, the heat dissipation effect is enhanced, meanwhile, rigid gaps between the shielding cover and the printed board assembly are dynamically eliminated, and the shielding effect is improved. Edge diffraction leakage is avoided; the technical effects of improving the vibration stability, improving the high-temperature adaptability, improving the shielding performance and improving the signal receiving stability can be achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of satellite navigation and positioning, and particularly relates to a high-stability satellite receiver. BACKGROUND

[0002] The satellite receiver is a key equipment integrating the core technology of the Beidou satellite navigation system (BDS), and mainly completes the core functions of satellite signal acquisition, tracking, positioning, short message, etc. in combination with the SBAS satellite-based augmentation function, and provides synchronous and asynchronous serial port output logic. As the terminal core of the satellite navigation system, the satellite receiver has irreplaceability in the fields of military command, disaster relief, marine fishery, etc., is a basic infrastructure for guaranteeing accurate acquisition of position information, and is a key technical carrier for realizing all-weather and all-region communication and positioning, and has strategic significance for improving the anti-interference capability and emergency response efficiency of the system.

[0003] The existing shield cover has multiple integration defects, which affects the overall performance of the receiver. Specifically, the fixed partition cavity is usually separated by a rigid metal partition plate, relies on physical isolation but cannot deform to adapt to environmental temperature changes, resulting in insufficient high-temperature adaptation stability. At the same time, the passive heat dissipation mechanism only relies on the convex post to paste the heat-conducting rubber pad to transfer heat, and the heat dissipation area is limited, which cannot efficiently suppress temperature rise, and aggravates the vibration stability risk. In terms of shielding performance, the static shielding is mainly designed for specific frequency bands, lacks flexibility to cope with high-frequency interference, and affects the stability of the received signal. In addition, the assembly gap problem is prominent. When the rigid gap between the side wall of the shield cover partition cavity and the printed board assembly is too large, edge diffraction leakage will be caused, which further weakens the shielding effectiveness and causes inaccurate positioning. SUMMARY

[0004] The 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] The application provides a high-stability satellite receiver, which includes a receiver body and an external anti-interference antenna, and the receiver body includes a printed board assembly and a shield cover. The printed board assembly includes an interface processing unit, a baseband processing unit, a power management unit and a radio frequency link unit. The shield cover is provided with a plurality of self-adapting plates arranged vertically, and each self-adapting plate includes a side plate and a partition plate. The self-adapting plate is provided with three layers and has a wave-shaped triangular sawtooth structure. The self-adapting plate is expanded by heat and presses the heating elements of the printed board assembly, so that the heat dissipation effect is strengthened, and the rigid gap between the shield cover and the printed board assembly is dynamically eliminated to avoid edge diffraction leakage.

[0006] Further, the interface processing unit comprises an FPGA chip, a clock circuit, a FLASH and a bus circuit, which are used for completing the interaction of external data; the baseband processing unit comprises a baseband chip, a memory, a chip, a clock circuit, which are used for completing the capture, tracking, PVT solution of signals, and completing the packaging and spread spectrum of short message information.

[0007] Further, the power management unit is used for supplying power for the baseband chip, the radio frequency chip, the FPGA and the peripheral circuit; the radio frequency link unit comprises a multiplexer, a power divider, an LNA low noise amplifier, a SAW sound table filter and a radio frequency chip, which are used for receiving and transmitting satellite signals; the radio frequency chip is a four-receiving-one-transmitting multi-mode multi-frequency chip, which has four receiving channels and one transmitting channel, and forms a multi-frequency point integration.

[0008] Further, the radio frequency port of the radio frequency link unit is fixed with a limiter, which is used for preventing the damage of intentional or unintentional high-power input signals, so that the radio frequency link unit has the power burnout resistance ability and improves the environmental adaptability of the receiver body.

[0009] Further, the external radio frequency interface of the receiver body is fixed with a radio frequency lightning suppressor, which has an indirect lightning protection ability and is used for protecting the radio frequency transceiver equipment to reliably operate in a complex environment.

[0010] Further, the shielding cover comprises a cover plate, a connecting block, a side plate, a partition cavity and a partition plate; The cover plate is a rectangular metal plate structure as a basic support component; the connecting block is provided with four connecting blocks and is welded to the four corners of the cover plate and is fixed with the printed board assembly through bolts; the side plate is provided with four side plates and is a wave-shaped structure and corresponds to the four end faces of the cover plate; the partition cavity is formed by the partition plate and is used for forming a closed shielding area and separating the electronic components in the printed board assembly to avoid electromagnetic interference.

[0011] Further, the side plate and the partition plate are provided with three layers, including an outer layer, an intermediate layer and an inner layer; The outer layer is a wave-shaped triangular sawtooth structure made of metal and internally etched with a micropore array, which is used for conducting electricity and high-frequency shielding; the intermediate layer is a sealed capsule structure and is contracted and expanded through temperature change; the inner layer is made of silica gel and contains silver particles and is fixedly connected with the outer layer, which is used for expanding the inner layer silica gel through the expansion of the intermediate layer to directly contact the heating elements of the printed board assembly, so as to strengthen the heat dissipation, and at the same time, the silver particle-silica gel layer fills the gaps between the components to dynamically eliminate the electromagnetic leakage gap and improve the shielding effect.

[0012] Further, the outer layer of the side plate is etched with a micro piezoelectric sensor, the piezoelectric sensor is made of lead zirconate titanate PZT material, arranged in a matrix grid shape, and located in the high-frequency interference sensitive area of the side wall of the shielding cover cavity, the piezoelectric sensor electrode is connected to the internal circuit of the shielding cover through a micro welding point, forming a closed loop detection path, and realizing real-time detection of 1-6GHz frequency band electromagnetic interference intensity through electromagnetic field coupling.

[0013] Further, the inner layer of the middle layer is filled with a liquid, which includes strontium titanate nanofluid, n-octadecane, carbon nanotube and graphene oxide, the strontium titanate nanofluid is used to change its own viscosity in response to the voltage generated by the piezoelectric sensor, realize the adaptive expansion of the interference intensity, account for 60% of the total composition; n-octadecane accounts for 30% of the total composition, which is used to drive the temperature adaptive deformation; carbon nanotube accounts for 5% of the total composition, which is used to enhance heat conduction and form an electromagnetic wave absorption network; graphene oxide accounts for 5% of the total composition, which is used to stabilize the dispersion of nanofluid and improve the shear strength.

[0014] Further, the middle layer is an elliptical balloon structure, the concentration of n-octadecane at the long axis end point (low curvature area) of the ellipse increases from the center to the end point, which is used to compensate for the heat conduction lag, accelerate the phase change heat absorption and improve the latent heat release rate; the concentration at the midpoint of the short axis (high curvature area) decreases from the center to the end point, which is used to reduce the volume expansion of the phase change and avoid interface stress cracking; The concentration of strontium titanate at the long axis end point (low curvature area) decreases from the center to the end point, which is used to reduce the mechanical resistance of phase change; the concentration at the midpoint of the short axis (high curvature area) increases from the center to the midpoint of the short axis, which is used to enhance the local dielectric response and make up for the uneven electric field caused by curvature.

[0015] One or more technical solutions provided in the application have at least the following technical effects or advantages: By adopting the wave-shaped side plate and the baffle, the longitudinal vibration energy is converted into transverse deformation through the cantilever beam effect of the corrugated folds to disperse and absorb high-frequency vibration energy; the three-layer composite adaptive structure can adapt to the environment (temperature, vibration and strong interference conditions) and can avoid stress cracking and enhance dielectric response through real-time monitoring of the piezoelectric sensor and the distribution design of n-octadecane and strontium titanate, further improving the electromagnetic shielding effectiveness; the double protection of the limiter and the lightning suppressor provides the first level of protection against high-power burnout and the second level of protection against lightning pulses for the receiver body, further improving the stability of the received signal of the satellite receiver and improving the positioning accuracy; effectively 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. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The exploded view of the structure of the high-stability satellite receiver.

[0017] Figure 2 The structure diagram of the printed board assembly of the high-stability satellite receiver.

[0018] Figure 3 The perspective structure diagram of the shielding cover of the high-stability satellite receiver.

[0019] Figure 4 The lateral structure diagram of the shielding cover of the high-stability satellite receiver.

[0020] Figure 5 The bottom view of the shielding cover of the high-stability satellite receiver.

[0021] Figure 6 The principle diagram of the high-stability satellite receiver. Figure 5 The full sectional view of the high-stability satellite receiver.

[0022] Figure 7 The principle diagram of the high-stability satellite receiver. Figure 6 The partial enlarged diagram of the high-stability satellite receiver.

[0023] Figure 8 The principle diagram of the high-stability satellite receiver. Figure 6 The partial enlarged diagram of the high-stability satellite receiver.

[0024] Figure 9 The principle diagram of the high-stability satellite receiver.

[0025] Figure 10 The technical roadmap of the high-stability satellite receiver.

[0026] Figure 11 The radio frequency link unit block diagram of the high-stability satellite receiver.

[0027] Figure 12 The power divider selection parameter table of the high-stability satellite receiver.

[0028] Figure 13 The SAW filter selection parameter table of the high-stability satellite receiver.

[0029] Figure 14 The baseband processing unit block diagram of the high-stability satellite receiver.

[0030] Figure 15Block diagram of interface processing unit of high-stability satellite receiver.

[0031] Figure 16 Circuit diagram of RF interface lightning protection of high-stability satellite receiver.

[0032] Figure 17 Circuit diagram of short-circuit protection of high-stability satellite receiver.

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

[0034] In order to facilitate the understanding of the present application, the present application will be described in more detail below with reference to the relevant drawings; the preferred embodiments of the present application are shown in the drawings, but the present application can be implemented in many different forms, and is not limited to the embodiments described herein; on the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0035] It should be noted that the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for illustrative purposes, and are not intended to be the only embodiment.

[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 the present application belongs; the terms used herein in the specification of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application; the term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] Please refer to 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 is configured to supply power for a baseband chip, a radio frequency chip, an FPGA and a peripheral circuit; the radio frequency link unit 114 includes a multiplexer, a power divider, an LNA low noise amplifier, a SAW surface acoustic wave filter and a radio frequency chip, and is configured to receive and transmit satellite signals; the radio frequency chip is a four-receiving-one-transmitting multi-mode multi-frequency chip, has four receiving channels and one transmitting channel, and forms multi-frequency point integration. The system flexibility and scalability can be improved, the hardware cost can be reduced, and the equipment maintenance workload can be reduced.

[0041] The radio frequency port of the radio frequency link unit 114 is fixed with a limiter 115, which is configured to prevent intentional or unintentional high-power input signals from being damaged, so that the limiter 115 has a power burnout resistance ability, and the environmental adaptability of the receiver body 100 is improved. The external radio frequency interface of the receiver body 100 is fixed with a radio frequency lightning suppressor, which has an indirect lightning protection ability, and is configured to protect the radio frequency transceiver device to reliably operate in a complex environment.

[0042] When suffering from a transient lightning waveform effect, the temporary performance is reduced, and the receiver body 100 can recover itself after the interference environment disappears. Meanwhile, the external antenna is fed in a straight-through case, and the radio frequency interface will not be damaged when a short circuit occurs, and can recover normal functions when the short circuit state disappears; meanwhile, the board card of the receiver body 100 integrates radio frequency circuit and digital circuit, in order to ensure the reliable work of the radio frequency circuit, the radio frequency circuit ground and the digital circuit ground are designed through single-point grounding, so that the ground isolation is realized.

[0043] The receiver device of the application generally includes the receiver body 100 and an anti-interference antenna, can receive satellite B1C, B3I and other civil signals, has three independent positioning modes of BDS B3 / B1 dual-frequency, BDS B3 single-frequency and BDS B1 single-frequency, supports SBAS (satellite-based augmentation) function; the receiver device can output real-time position, speed, time and other information of a carrier, and can receive inertial information of an inertial navigation system to assist in improving the dynamic performance, suppressing the influence of noise on precision and improving the anti-interference ability. The receiver device has the ability to resist six-direction suppression interference, has the ability to prevent deception, and has the functions of RDSS (satellite radio determination service) regional short message and global short message communication.

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

[0045] As shown in Figures 6 to 8 The side plate 230 and the partition plate 250 are provided with three layers, including an outer layer 201, an intermediate layer 202 and an inner layer 203; The outer layer 201 is a wave-shaped triangular sawtooth structure made of metal, with a micro-pore array etched inside, used for electric conduction and high-frequency shielding; the intermediate layer 202 is a sealed cavity structure, which shrinks and expands by temperature change; the inner layer 203 is made of silica gel and contains silver particles, fixedly connected with the outer layer 201, used to expand by the intermediate layer 202, so that the silica gel of the inner layer 203 directly contacts the heating elements of the printed board assembly 110 under the expansion of the intermediate layer 202, to strengthen heat dissipation, and at the same time, fill the gaps between the elements through the silver particle-silica gel layer, to dynamically eliminate electromagnetic leakage gaps and improve shielding effect. The outer layer 201 is made of beryllium copper alloy.

[0046] The longitudinal vibration energy can be converted into transverse deformation by the wave-shaped side plate 230, to disperse and absorb displacement energy in high-frequency vibration (≥15G), improve vibration stability, and increase the heat dissipation surface area through the wave structure, so that the heat dissipation capacity can be improved, the electromagnetic wave propagation path can be lengthened, the diffraction loss can be increased, and the high-frequency shielding effectiveness can be improved.

[0047] By adopting the three-layer composite structure, the intermediate layer 202 is a sealed cavity and can expand under heat to push the silver particle-containing silica gel inner layer 203 to closely fit the heating elements of the printed board assembly 110, fill the gaps between the elements, eliminate the assembly rigid gaps, avoid edge diffraction leakage, and dynamically eliminate electromagnetic leakage gaps; at the same time, the micro-pore array (etched in the metal layer) of the outer layer 201 opens at high temperature to form an air flow channel, to strengthen convective heat dissipation; at high temperature, the liquid 261 (n-octadecane) of the intermediate layer 202 phase changes and expands (volume expands), to press the silica gel of the inner layer 203 to directly contact the chip, so that the heat dissipation efficiency is further improved; when at low temperature, the intermediate layer 202 shrinks, the micro-pores close to reduce heat loss, and temperature self-adaptive deformation is realized.

[0048] As shown in Figure 8As shown, the partition 250 is composed of two partitions 250, which are mirror placed, and the outer layers 201 of the two partitions 250 are fixed to form a whole wave-shaped metal plate, and the inner layers 203 on both sides are expanded to the two sides respectively in the expanded state, and contact the elements on both sides to reduce the rigid gap between the elements on both sides.

[0049] As shown, the outer layer 201 of the side plate 230 is etched with a micro piezoelectric sensor 260, which is made of lead zirconate titanate PZT material and arranged in a matrix grid shape, and located at the high-frequency interference sensitive area of the side wall of the shielding cover 200 cavity 240. The electrode of the piezoelectric sensor 260 is connected to the internal circuit of the shielding cover 200 through a micro welding point to form a closed loop detection path, and realizes real-time detection of electromagnetic interference intensity in the frequency band of 1-6GHz through electromagnetic field coupling. Figures 6 to 8 The inner layer 202 is internally provided with a liquid 261, which includes strontium titanate nanofluid, n-octadecane, carbon nanotube and graphene oxide. The strontium titanate nanofluid is used to change its own viscosity in response to the voltage generated by the piezoelectric sensor 260 to realize adaptive expansion of interference intensity, accounting for 60% of the total composition; n-octadecane accounts for 30% of the total composition and is used to drive temperature adaptive deformation; carbon nanotube accounts for 5% of the total composition and is used to enhance heat conduction to form an electromagnetic wave absorption network; and graphene oxide accounts for 5% of the total composition and is used to stabilize the dispersion of nanofluid and improve shear strength.

[0050] Through the interference response mechanism of the piezoelectric sensor 260 and the intelligent fluid, the piezoelectric sensor 260 (PZT material) detects the electromagnetic interference in the frequency band of 1-6GHz in real time, generates a voltage signal to drive the strontium titanate nanofluid to change the viscosity, and when strong interference is detected (such as 5GHz radar), the fluid viscosity of the liquid 261 is reduced, the intermediate layer 202 is expanded to accelerate, and the rigid physical gap is eliminated, so that the shielding effectiveness is guaranteed. Correspondingly, when in a high-temperature and strong-interference state, the n-octadecane (PCM) phase change expansion and the dielectric fluid response are superimposed to optimize the heat dissipation and shielding simultaneously.

[0051] Further, the intermediate layer 202 is an elliptical balloon structure, the concentration of n-octadecane at the long axis end point (low curvature area) of the ellipse increases from the center to the end point, which is used to compensate for the heat conduction lag, accelerate the phase change heat absorption, and improve the latent heat release rate; and the concentration at the midpoint of the short axis (high curvature area) decreases from the center to the end point, which is used to reduce the volume expansion of the phase change body and avoid interface stress cracking.

[0052] ​The concentration of strontium titanate decreases from the center to the end point of the long axis (low curvature area) to reduce the mechanical resistance of the phase transition; the concentration at the midpoint of the short axis (high curvature area) increases from the center to the midpoint of the short axis to enhance the local dielectric response and compensate for the uneven electric field caused by curvature.

[0053] The present application optimizes the gradient concentration distribution of n-octadecane (PCM) and strontium titanate in the elliptical balloon body, i.e. the gradient distribution of liquid 261 formula (n-octadecane / strontium titanate concentration adjusted according to the curvature of the elliptical balloon), which can avoid interface stress cracking, improve dielectric response, and realize the synergistic optimization of thermal management and electromagnetic regulation by precisely adapting the geometric curvature characteristics.

[0054] The piezoelectric sensor 260 is used to detect 1-6 GHz electromagnetic interference in real time, preferably a TDK PSF series piezoelectric film sensor; all are prior art and will not be described here.

[0055] Overall, the receiver body 100 is designed with efficient heat dissipation and electromagnetic shielding (such as the shielding cover 200) to ensure 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. the radio frequency link unit 114), the positioning information is calculated by the baseband processing unit 112, and then the position, speed and time data are output through the interface processing unit 111; the detailed principle is as follows: As Figure 9 shown, the receiver device working principle diagram mainly completes satellite signal acquisition, tracking, positioning and short message processing, supports multiple positioning modes such as BDS B1 / B3 dual frequency, and has anti-interference and anti-fraud capabilities; its working principle diagram includes the following key parts: the radio frequency link unit 114 is used to receive B1 / L1 / E1, B3, S, B2b, etc. satellite signals, and through the components such as limiter 115, multiplexer, LNA low noise amplifier, SAW filter, etc. to realize anti-burnout design (resistance to 30dBm power) and transceiver link optimization; the baseband processing unit 112 is composed of baseband chips, memory (such as 128Mbit SPIFLASH and 1Gb DDR3) and clock circuit, which completes signal acquisition, tracking, PVT calculation (position, speed, time) and short message packaging spread spectrum; the interface processing unit 111 processes external data interaction based on FPGA chip, including data transfer, arbitration and communication format packaging, supports self-detection and software upgrade.

[0056] As 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 temperature range is -55℃-125℃, the storage capacity is 512Mb, the maximum erasing and writing times are 100000, the data storage time is up to 20 years, and the FLASH can meet the needs of the application; wherein the clock circuit is composed of a temperature compensation crystal oscillator and a clock driving chip, the crystal oscillator generates a frequency of 20MHz, and is used to provide a reference frequency for the FPGA chip, and the temperature range of the selected domestic temperature compensation crystal oscillator and clock driving chip is -55℃-105℃.

[0070] The clock circuit is composed of a temperature compensation crystal oscillator and a clock driving chip, and the crystal oscillator generates a frequency of 20MHz, and is used to provide a reference frequency for the FPGA chip; the selected domestic temperature compensation crystal oscillator and clock driving chip have a temperature range of -55℃-105℃, and meet the requirements of the use environment.

[0071] (3) Power supply unit (i.e. power management unit 113) The power management unit 113 is used to supply power for the baseband chip, the radio frequency chip, the FPGA and the peripheral circuit, the 5V power supply of the receiver body 100 is provided by an inertial navigation or a navigation posture, and is converted into voltages such as 3.3V, 1.8V and 1.0V through a power chip; the temperature range of the selected power chip is -55℃-125℃; the 3.3V time-keeping power supply is provided by the inertial navigation or the navigation posture for the receiver, and the receiver supplies power for the RTC chip part after filtering.

[0072] There are mainly three kinds of circuit protection for the satellite receiver, namely lightning protection, short circuit protection and ground isolation.

[0073] 1. Lightning protection As shown in Figure 16 , it is a circuit block diagram of the lightning protection circuit of the radio frequency interface; the radio frequency interface of the receiver has an indirect lightning protection capability, and when suffering from instantaneous lightning waveform effect, the temporary performance is temporarily reduced, and can be restored automatically after the interference environment disappears, and the experimental level is not less than level 3. A radio frequency lightning suppressor is preferably used to protect the radio frequency transceiver equipment to reliably operate in a complex environment. The satellite receiver covers all the frequency points in the application, as shown in Figure 16 , it is a circuit diagram of the lightning protection circuit of the radio frequency interface; the performance indicators are as follows: standing wave ratio: not more than 1.5:1; insertion loss: not more than 0.5dB; maximum power: not more than 20W; feed 5V; lightning protection level: A3.

[0074] 2. Short circuit protection As shown in Figure 17As shown in the figure, it is a short circuit protection circuit block diagram; the antenna is fed in a straight-through case, and when a short circuit occurs at the radio frequency interface, the product will not be damaged, and when the short circuit state disappears, the normal function can be restored. When the short circuit protection chip is selected, the main performance is as follows: input range: 2.5V-5.5V; on-resistance: 45mΩ; maximum current: 3A; current limiting point is adjustable; it has self-recovery thermal protection function.

[0075] 3. Ground isolation The receiver board card integrates radio frequency circuit digital circuit, in order to ensure the reliable work of the radio frequency circuit, the ground of the radio frequency circuit and the ground of the digital circuit are designed through single point grounding.

[0076] The receiver is composed of printed boards, components, shielding cover 200, connectors and other parts, including the weight of each part: printed board 15g, component 21g, shielding cover 35g, connector 5g, other parts 2g; the weight of the satellite receiver is 78g, which can meet the technical requirement that the weight of the receiver is ≤200g, wherein the physical characteristics of the satellite receiver include: weight ≤0.2kg; power supply voltage: 5VDC±5%; power consumption: ≤8W (in all states). The power supply voltage range of the anti-interference antenna is 18VDC-32VDC; its power consumption is not greater than 70W (in non-emission state) and not greater than 100W (in emission state). The temperature adaptability requirement is that the working temperature is maintained at-55℃-+85℃ (receiver module), -55℃-+70℃ (anti-interference antenna); the storage temperature is maintained at-55℃-+85℃ (receiver module), -55℃-+70℃ (anti-interference antenna).

[0077] The 5V power supply full state power consumption of the receiver is analyzed and predicted, including: baseband chip + DDR + FLASH (steady state: 0.5W, peak value: 0.8W), chip 0.5W, FPGA + FLASH 3.5W, radio frequency chip 1W. If the power supply conversion efficiency is 85%, then the steady state power consumption of the receiver in all states is 5.5 / 0.85=6.5W, and the peak power consumption in all states is 5.8W / 0.85=6.8W, which can meet the power consumption requirement of ≤8W (in all states).

[0078] In actual operation, the steps of the embodiment of the present application are as follows: Step one: environmental parameter perception and signal reception Firstly, the external anti-interference antenna captures B1 / L1 / E1, B3, S, B2b and other satellite signals, and the signals are processed by the radio frequency link unit 114: through the limiter 115 anti-burnout protection, multiplexer, LNA low noise amplifier, SAW sound table filter in turn, and finally down-converted by the radio frequency chip; The piezoelectric sensor 260 in the side plate 230 of the shielding cover 200 detects electromagnetic interference in the 1-6 GHz frequency band in real time. When strong interference is detected, such as a 5 GHz radar pulse, the piezoelectric effect is triggered, generating a voltage signal. The stronger the interference, the higher the voltage. Step two: adaptive shielding and heat dissipation response When the ambient temperature is greater than 28℃, the n-octadecane PCM in the middle layer 202 melts into a liquid state, expanding by 1.5 times in volume. The expansion pushes the inner layer 203 containing silver-containing silica gel to tightly adhere to the heat generating elements (such as baseband chips) of the printed board assembly 110, eliminating assembly gaps. The piezoelectric voltage acts on the strontium titanate nanofluid in the middle layer 202, reducing its viscosity and enhancing the fluidity of the fluid. The PCM diffusion is accelerated, and the airbag inflation rate is improved. The shielding cover 200 can quickly adhere to the printed board assembly 110, making it flexible to adapt to shielding requirements under strong interference and dynamically eliminating electromagnetic leakage. At the same time, the high-temperature micro-pore array in the outer layer 201 is heated and expanded to form air flow channels, and hot air escapes through the micro-pores by the chimney effect, improving the heat dissipation efficiency. Step three: signal processing and positioning output The down-converted signal is transmitted to the baseband processing unit 112, which completes signal capture, tracking, and PVT (Position, Velocity, Time) position / speed / time calculation, and synchronously processes short message information packaging and spread spectrum. The FPGA chip of the interface processing unit 111 packages the calculation data and outputs position, speed, and time information through a serial port. Step four: extreme environment adaptability adjustment When in the low-temperature contraction mechanism state, i.e., when the ambient temperature is less than 28℃, the n-octadecane (PCM) solidifies and contracts, restoring the thickness of the capsule body in the middle layer 202 to the initial value and closing the micro-pores to reduce heat loss. At this time, the piezoelectric sensor 260 adjusts the fluid viscosity to suppress excessive contraction and maintain basic shielding effectiveness. At the same time, under high-frequency vibration of ≥15G, the wave-shaped side plate 230 absorbs longitudinal vibration energy through the corrugated folds and converts it into transverse deformation, ensuring the stability of the printed board assembly 110. Step five: protection mechanism linkage The lightning suppressor at the radio frequency port resists indirect lightning strikes and ensures that the device recovers automatically after the interference disappears. The short-circuit protection chip triggers current limiting when the radio frequency interface is abnormal and automatically resets after the fault is resolved.

[0079] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages: The technical problems of poor vibration stability, low temperature adaptability, limited shielding performance, and poor receiving signal stability in the prior art are effectively solved, achieving the technical effects of improved vibration stability, improved high-temperature adaptability, improved shielding performance, and improved receiving signal stability.

[0080] The above merely describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-stability satellite receiver characterized by, The receiver body (100) comprises a printed board assembly (110) and a shielding cover (200); The printed board assembly (110) comprises an interface processing unit (111), a baseband processing unit (112), a power management unit (113) and a radio frequency link unit (114); The shielding cover (200) is provided with a plurality of adaptive plates arranged vertically, the adaptive plate comprises a side plate (230) and a partition plate (250), the adaptive plate is provided with three layers, is in a wavy triangular sawtooth structure, is expanded by heating and presses the heating element of the printed board assembly (110), the heat dissipation effect is strengthened, meanwhile, the rigid gap between the shielding cover (200) and the printed board assembly (110) is dynamically eliminated, and edge diffraction leakage is avoided.

2. A high-stability satellite receiver as claimed in claim 1, characterized in that The interface processing unit (111) comprises an FPGA chip, a clock circuit, a FLASH and a bus circuit, and is used for completing the interaction of external data; the baseband processing unit (112) comprises a baseband chip, a memory, a chip and a clock circuit, and is used for completing the capture, tracking and PVT solution of signals, and completing the packaging and spread spectrum of short message information.

3. A high-stability satellite receiver as claimed in claim 1, characterized in that The power management unit (113) is used for supplying power for the baseband chip, the radio frequency chip, the FPGA and the peripheral circuit; the radio frequency link unit (114) comprises a multiplexer, a power divider, an LNA low noise amplifier, a SAW sound table filter and a radio frequency chip, and is used for receiving and transmitting satellite signals; the radio frequency chip is a four-receiving-one-transmitting multi-mode multi-frequency chip, has four receiving channels and one transmitting channel, and forms a multi-frequency point integration.

4. A high-stability satellite receiver as claimed in claim 1, characterized in that The radio frequency port of the radio frequency link unit (114) is fixed with a limiter (115), which is used for preventing the damage of intentional or unintentional high-power input signals, has the power burnout resistance, and improves the environmental adaptability of the receiver body (100).

5. A highly stable satellite receiver as claimed in claim 1, wherein, The external radio frequency interface of the receiver body (100) is fixed with a radio frequency lightning suppressor, has an indirect lightning protection capability, and is used for protecting the radio frequency transceiver equipment to reliably operate in a complex environment.

6. A highly stable satellite receiver as claimed in claim 1, wherein, The shielding cover (200) comprises a cover plate (210), a connecting block (220), a side plate (230), a partition cavity (240) and a partition plate (250); The cover plate (210) is a rectangular metal plate structure and serves as a basic support assembly; the connecting block (220) is provided with four connecting blocks and is welded at four corners of the cover plate (210) and is fixed with the printed board assembly (110) through bolts; the side plate (230) is provided with four side plates and is in a wavy structure and corresponds to four end faces of the cover plate (210); the partition cavity (240) is formed by the partition plate (250) and is used for forming a closed shielding area and separating electronic components in the printed board assembly (110) to avoid electromagnetic interference.

7. A highly stable satellite receiver as claimed in claim 6, characterized in that The side plate (230) and the partition plate (250) are both provided with three layers, comprising an outer layer (201), an intermediate layer (202) and an inner layer (203). The outer layer (201) is a wavy triangular sawtooth structure made of metal material, and has a micro-pore array etched inside for electric conduction and high-frequency shielding; the middle layer (202) is a sealed cavity structure that shrinks and expands through temperature change; the inner layer (203) is made of silica gel material and has silver particles inside, and is fixedly connected with the outer layer (201), for expanding through the middle layer (202) to directly contact the printed board assembly (110) heating element under the expansion of the middle layer (202), to strengthen heat dissipation, and at the same time, fill the gaps between elements through the silver particle-silica gel layer, to realize dynamic elimination of electromagnetic leakage gaps and improve the shielding effect.

8. A highly stable satellite receiver as claimed in claim 7, characterized in that The outer layer (201) of the side plate (230) is etched with a micro piezoelectric sensor (260), the piezoelectric sensor (260) is made of lead zirconate titanate PZT material, arranged in a matrix grid shape, and located in the high-frequency interference sensitive area of the side wall of the shielding cover (200) cavity (240), the piezoelectric sensor (260) electrode is connected to the internal circuit of the shielding cover (200) through a micro welding point, forming a closed loop detection path, and realizing real-time detection of 1-6GHz frequency band electromagnetic interference intensity through electromagnetic field coupling.

9. A highly stable satellite receiver as claimed in claim 8, characterized in that, The middle layer (202) is internally provided with a liquid (261), the liquid (261) includes strontium titanate nanofluid, n-octadecane, carbon nanotube and graphene oxide, the strontium titanate nanofluid is used to change its own viscosity in response to the voltage generated by the piezoelectric sensor (260), to realize adaptive expansion of the interference intensity, accounting for 60% of the total composition; n-octadecane accounts for 30% of the total composition, for driving temperature adaptive deformation; carbon nanotube accounts for 5% of the total composition, for enhancing heat conduction and forming an electromagnetic wave absorption network; graphene oxide accounts for 5% of the total composition, for stabilizing the dispersion of nanofluid and improving the shear strength.

10. A highly stable satellite receiver as claimed in claim 9, characterized in that The middle layer (202) is an elliptical balloon structure, the concentration of n-octadecane at the long axis end point (low curvature area) increases from the center to the end point, for compensating for thermal conduction lag, accelerating phase change heat absorption, and improving latent heat release rate; The concentration of n-octadecane at the short axis midpoint (high curvature area) decreases from the center to the end point, for reducing the volume expansion of the phase change body and avoiding interface stress cracking; The concentration of strontium titanate at the long axis end point (low curvature area) decreases from the center to the end point, for reducing the mechanical resistance of phase change; and the concentration at the short axis midpoint (high curvature area) increases from the center to the short axis midpoint, for enhancing local dielectric response and making up for the uneven electric field caused by curvature.

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