GNSS and satellite short message two-in-one vehicle-mounted antenna

Abstract

The antenna comprises a shell composed of an upper shell and a lower shell, and further comprises an antenna module arranged in the shell. The antenna module comprises a PCB (Printed Circuit Board), an antenna arranged above the PCB and a shielding cover arranged below the PCB, and the antenna comprises a first antenna working in a 1.2 GHz frequency band, a second antenna working in a 1.6 GHz frequency band and a third antenna working in a 2.4 GHz frequency band; the PCB is provided with three radio frequency links, namely a GNSS (Global Navigation Satellite System) receiving link, a satellite short message receiving link and a satellite short message transmitting link, and the three radio frequency links are respectively connected with the three groups of antennas. According to the invention, the GNSS and satellite short message two-in-one vehicle-mounted antenna is realized, the cost is saved, the arrangement of the whole vehicle-mounted antenna system is facilitated, and the vehicle-mounted antenna has the characteristics of economy, convenience, attractive appearance and strong received signal.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and in particular relates to a vehicle-mounted antenna that combines GNSS and satellite short message services. Background Technology

[0002] In the automotive field, the high-precision positioning function of Global Navigation Satellite Systems (GNSS) and the network-free communication function of satellite short messages (such as BeiDou-3 short messages) jointly support the core needs of scenarios such as intelligent connected vehicles, commercial vehicle monitoring, and emergency rescue vehicles. The former provides real-time location information to ensure navigation and fleet management, while the latter enables two-way data transmission in remote or emergency scenarios without terrestrial mobile communication networks (4G / 5G). Both are indispensable.

[0003] Currently, the implementation schemes for GNSS and satellite short message functions in vehicle-mounted scenarios have significant shortcomings and are difficult to meet the needs of practical applications: Firstly, the separate solution requires two independent hardware modules (including antenna, radio frequency link, and control unit) to achieve positioning and communication respectively. This not only occupies too much vehicle space and increases installation and wiring costs, but also easily causes signal interference due to adjacent frequency bands, resulting in GNSS positioning drift and short message communication packet loss. Furthermore, the two module control units are independent, making it impossible to achieve real-time data fusion and increasing system latency.

[0004] Secondly, although early integration solutions attempted to integrate functions, they still failed to overcome key bottlenecks: the module size was mostly above 68mm×68mm×10.1mm, making it unsuitable for compact installation spaces such as the center console and front dashboard; the RF link design did not take into account the performance differences between the two, often resulting in imbalances such as excessively high GNSS noise figure (>1.2dB) or insufficient short message reception sensitivity (>-125dBm); and most of them only supported a single GNSS system and fixed frequency band, resulting in poor compatibility and inability to adapt to multi-system compatibility and the new frequency band requirements of Beidou-3.

[0005] In addition, existing solutions generally fail to meet automotive-grade environmental adaptability requirements, and are prone to performance degradation under extreme temperatures of -40℃ to 85℃ and vibrations of 10Hz to 2000Hz (ISO 16750 standard), making it impossible to guarantee long-term reliable operation. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A vehicle-mounted antenna that combines GNSS and satellite short message services includes a housing consisting of an upper shell and a lower shell, characterized in that it further includes an antenna module disposed within the housing; The antenna module includes a PCB board, an antenna mounted on the PCB board, and a shielding cover mounted below the PCB board. The antenna includes a first antenna operating in the 1.2 GHz band, a second antenna operating in the 1.6 GHz band, and a third antenna operating in the 2.4 GHz band. All three antennas are made of PPO material. The first antenna is used to receive two GNSS signals with a phase difference of 90°. The second antenna is used to receive the 1.6 GHz GNSS signal and the uplink signal of BeiDou short message. The third antenna is used to receive one downlink signal of BeiDou short message. The antenna is equipped with T-shaped patches around its perimeter; these T-shaped patches are used to widen the antenna beamwidth and improve signal coverage in vehicle-mounted scenarios. The PCB board is provided with three radio frequency links, namely a GNSS receiving link, a satellite short message receiving link, and a satellite short message transmitting link, and the three radio frequency links are respectively connected to the three sets of antennas; The PCB board is also connected to a Fakra connector.

[0007] Furthermore, the GNSS receiving link includes a dual-band pre-filter, a first-stage amplifier, and a second-stage amplifier connected in sequence; the noise figure of the GNSS receiving link is 0.7-1.1dB, and the total gain is not less than 38dB.

[0008] Furthermore, the satellite short message receiving link includes a first filter, a third-stage amplifier, a second filter, and a fourth-stage amplifier connected in sequence; the noise figure of the satellite short message receiving link is not higher than 0.8dB, and the total gain is not lower than 36dB.

[0009] Furthermore, the satellite short message transmission link includes a third filter, a fifth amplifier, and a sixth amplifier connected in sequence; the maximum output power of the satellite short message transmission link is not less than 36.5dBm, and the total gain is not less than 52dB.

[0010] Furthermore, the first antenna and the second antenna adopt a single-layer dual-frequency structure design; the single-layer dual-frequency structure includes an outer square patch and an inner patch, the outer square patch is used to process low-frequency signals, and the inner patch is used to process high-frequency signals.

[0011] Furthermore, the third antenna adopts a stacked structure design; the stacked structure consists of a single-fed right-hand circularly polarized antenna loaded above the first antenna, used to realize high-frequency signal transmission of satellite short messages.

[0012] Furthermore, a metal pillar is provided within the antenna module; the metal pillar is used to isolate the feed points of different frequency bands in the three antenna components to avoid signal interference between frequency bands.

[0013] The beneficial effects of this invention are: 1. Significantly optimizes vehicle space usage, reducing installation and cost investment. Compared to separate solutions, this approach integrates GNSS and satellite short message functions into a single module, eliminating the need for two separate hardware and installation structures. This saves over 60% of vehicle installation space and allows for flexible adaptation to compact areas such as the dashboard and center console. It avoids the need for additional drilling into the roof or sides of the vehicle, reducing the complexity of vehicle modifications. The integrated design reduces the need for separate wiring and individual debugging, decreasing the number of components by over 40%. This not only lowers procurement costs but also shortens the assembly cycle of the vehicle terminal, improving mass production efficiency.

[0014] 2. Ensure stable positioning and communication performance, and resolve signal interference and imbalance issues. To address the performance differences between GNSS and short message services, three independent radio frequency links were designed: the GNSS receiving link boasts a noise figure as low as 0.7-1.1dB and a gain of 38dB, ensuring stable positioning accuracy (meter-level); the satellite short message receiving link achieves a sensitivity of -130dBm and a maximum output power of 36.5dBm, enabling reliable communication in remote areas or weak signal environments, with short message packet loss rate reduced to below 1%. By isolating feed points of different frequency bands with metal pillars and loading T-shaped patches around the antenna, frequency band interference between GNSS and short message signals is effectively avoided. Simultaneously, the antenna beamwidth is widened, improving signal coverage in vehicular scenarios (such as when vehicles are turning or obstructed in mountainous areas), resulting in positioning continuity and communication success rates exceeding 99%.

[0015] 3. Enhance compatibility and scalability to adapt to application needs in multiple scenarios. Supports compatibility with multiple GNSS systems including GPS, BeiDou, GLONASS, and Galileo, allowing for flexible switching based on navigation needs in different regions (such as China, Europe, and Southeast Asia). It meets the positioning requirements of export vehicles without requiring module replacement, thus broadening the product's applicability. Compatible with the BeiDou-3 short message system, it adapts to new short message frequency bands and protocols, meeting current vehicle emergency communication needs and accommodating future satellite communication system upgrades. This avoids module obsolescence due to technological iterations, extending the product's lifecycle. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the antenna structure of the present invention; Figure 3 This is the right-hand rotation reflection coefficient diagram (S33) of the antenna S-parameter 3 port of the present invention. Figure 4 This is the left-hand rotation reflection coefficient diagram (S33) of the antenna S-parameter 3 port of the present invention. Figure 5 This is the reflection coefficient diagram (S11) of the port S-parameter 1 of the antenna of the present invention. Figure 6 This is the reflection coefficient diagram (S55) of the antenna S-parameter 5 port of the present invention; Figure 7 This is the electric field amplitude diagram of the present invention (1.175GHz). Figure 8 This is the electric field amplitude diagram (1.575GHz) of the present invention. Figure 9 This is the electric field amplitude diagram (1.62GHz) of the present invention. Figure 10 This is the electric field amplitude diagram (2.49GHz) of the present invention. Figure 11 This is the current amplitude diagram (1.175GHz) of the present invention; Figure 12 This is the current amplitude diagram (1.575GHz) of the present invention; Figure 13 This is the current amplitude diagram (1.62GHz) of the present invention; Figure 14 This is the current amplitude diagram (2.49GHz) of the present invention; Figure 15 This is the 3D radiation pattern (1.175 GHz) of the antenna of this invention; Figure 16 This is the 3D radiation pattern (1.575 GHz) of the antenna of this invention; Figure 17 This is the 3D radiation pattern of the antenna of the present invention (1.62GHz). Figure 18 This is the 3D radiation pattern of the antenna of this invention (2.49GHz). Figure 19 This is the antenna gain diagram of the present invention (1.175GHz). Figure 20 This is the antenna gain diagram of the present invention (1.575GHz); Figure 21 This is the antenna gain diagram of the present invention (1.62GHz). Figure 22 This is the antenna gain diagram of the present invention (2.49GHz). Figure 23 This is the antenna axial ratio diagram of the present invention (1.175GHz). Figure 24 This is the antenna axial ratio diagram of the present invention (1.575GHz); Figure 25This is the antenna axial ratio diagram of the present invention (1.62GHz). Figure 26 This is the antenna axial ratio diagram of the present invention (2.49GHz). Figure 27 This is the antenna efficiency diagram of the present invention (1.175GHz). Figure 28 This is the antenna efficiency diagram of the present invention (1.575GHz); Figure 29 This is the antenna efficiency diagram of the present invention (1.62GHz). Figure 30 This is the antenna efficiency diagram of the present invention (2.49GHz). Figure 31 This is a diagram showing the test results of the short message method of this invention; Figure 32 This is a diagram showing the test results of the short message method of this invention; The parts in the attached diagram are labeled as follows: 1. Upper shell; 2. Lower shell; 3. Antenna module; 31. PCB board; 32. Antenna; 321. First antenna; 322. Second antenna; 323. Third antenna; 33. Shielding cover; 34. Fakra connector. Detailed Implementation

[0017] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0018] Example 1: This embodiment discloses a vehicle-mounted antenna that combines GNSS and satellite short message services. It is designed and manufactured strictly in accordance with the claims and description of this invention. The specific structure, material selection, and performance parameters are as follows: I. Overall Structure and Dimensions Housing: Both the upper housing 1 and the lower housing 2 are integrally injection molded from ABS engineering plastic. The upper housing measures 45mm × 45mm × 6mm, and the lower housing measures 45mm × 45mm × 4mm. The total volume of the housing is only 16200mm³, which is 65% smaller than the existing integrated solution (68mm × 68mm × 10.1mm, with a volume of approximately 46254mm³). It can be directly embedded into the compact space inside the center console without the need for additional drilling. The housing surface has a matte anti-static treatment, achieving an IP65 protection rating, making it suitable for the complex environment of an automotive vehicle.

[0019] Antenna Module 3: The entire module is embedded in the inner cavity of the housing and is fixedly connected to the housing through 4 M2 threaded posts. The total height of the module is 5.5mm, and the gap between the module and the inner wall of the housing is 0.5mm to ensure structural stability under vibration.

[0020] II. Detailed Design of Core Components (a) PCB board and shielding cover PCB board 31: It adopts FR-4 epoxy glass cloth substrate, with a thickness of 1.6mm and a size of 40mm×40mm. The surface copper thickness is 35μm. Three independent RF link traces are printed on the PCB board with a trace width of 0.8mm, impedance matching of 50Ω, and trace spacing ≥2mm to reduce crosstalk.

[0021] Shielding cover 33: Made of nickel silver, 0.3mm thick, 41mm×41mm×3mm in size, it is fixed to the bottom of the PCB board by soldering. The inner wall of the shielding cover is covered with 0.2mm thick conductive foam, which can effectively shield electromagnetic interference (EMI) generated by the engine, electronic control system, etc. in the vehicle environment, with a shielding effectiveness of ≥40dB.

[0022] (ii) Antenna assembly 32 Material and basic parameters: All three antennas are injection molded from PPO (polyphenylene oxide) material with a dielectric constant of 2.6, a loss tangent of 0.002, and a high temperature resistance range of -40℃ to 120℃, meeting automotive-grade environmental requirements.

[0023] The first antenna, 321, operates in the 1.2GHz band (center frequency 1.175GHz). It adopts a single-layer dual-band structure with an outer square patch design. The patch size is 30mm×30mm and the thickness is 1mm. It is used to receive two GNSS signals with a phase difference of 90° (supporting GPS L1 and Beidou B1C bands). T-shaped patches (5mm in length, 3mm in width, and 0.8mm in thickness) are loaded around the antenna. The beamwidth is 30% wider than that of traditional designs.

[0024] The second antenna 322 operates in the 1.6GHz band (center frequency 1.62GHz), adopts a single-layer dual-frequency structure with an intermediate patch design, the patch size is 15mm×15mm and the thickness is 1mm, and it is used to receive GNSS 1.6GHz signals (BeiDou B1A band) and BeiDou short message uplink signals (1.61GHz). It is also loaded with a T-shaped patch to ensure that there are no dead spots in the signal coverage in the vehicle scenario.

[0025] The third antenna 323 operates in the 2.4GHz band (center frequency 2.49GHz) and adopts a stacked structure design. A single-fed right-hand circularly polarized antenna (20mm×20mm in size and 3mm in height) is loaded on top of the first antenna to receive the downlink signal of Beidou short message (2.49GHz). The stacking spacing is 1.5mm and the polarization purity is ≥95%.

[0026] Metal pillars: Four copper metal pillars, 2mm in diameter and 4mm in height, are set inside the antenna module and are evenly distributed around the feed point of the three antenna components. The spacing between adjacent metal pillars is 8mm. This is used to isolate feed points of different frequency bands, with an inter-band isolation of ≥35dB to avoid signal interference.

[0027] (III) Radio Frequency Links and Connectors GNSS receiving link: A dual-band pre-filter (model SF1216-01, operating frequency band 1.1~1.7GHz, insertion loss ≤0.5dB), a first-stage amplifier (AD8352, gain 18dB, noise figure 0.5dB), and a second-stage amplifier (ADL5565, gain 22dB, noise figure 0.3dB) are connected in series to achieve a noise figure of 0.9dB and a total gain of 40dB, which meets the performance indicators of claim 2.

[0028] Satellite short message receiving link: The first filter (SF1624-02, operating frequency band 1.6~2.5GHz, insertion loss ≤0.4dB), the third amplifier (OPA847, gain 15dB), the second filter (SF1624-03, out-of-band rejection ≥60dB), and the fourth amplifier (LMH6629, gain 23dB) are connected in series. The noise figure is 0.7dB, the total gain is 38dB, and the receiving sensitivity reaches -132dBm, which is better than the requirements of claim 3.

[0029] Satellite short message transmission link: The third filter (SF2426-01, operating frequency band 2.4~2.6GHz, insertion loss ≤0.6dB), the fifth amplifier (MRF9045, gain 25dB), and the sixth amplifier (MRF9130, gain 30dB) are connected in series, with a maximum output power of 37dBm and a total gain of 55dB, which meets the BeiDou short message transmission power requirements (claim 4).

[0030] Fakra connector: The H-type Fakra connector (impedance 50Ω, insertion / removal life ≥1000 times) is used. It is connected to the PCB board via an RF coaxial cable. The connector is fixed to the side of the housing for easy docking with the vehicle terminal host.

[0031] III. Performance Test Results The vehicle-mounted antenna prepared in this embodiment was tested by a third-party testing agency, and its performance indicators are as follows: Positioning performance: As shown in Figure 31, the satellite search test lasted 0.07 hours, with a 100% positioning success rate and an average of 28 satellites searched. It supports multiple systems including GPS L1 / L5, GLO, GAL E1 / E5a, BDS B11 / B2A / B1C, and QZSS L1 / L5. The MaxCn0 value for each system is 45~53dBHz, the MeanCn0 value is 40~47dBHz, PDOP=1.65, HDOP=0.70, and VDOP=1.47, with a positioning accuracy of up to 2 meters.

[0032] Communication performance: Satellite short message receiving link sensitivity -132dBm, maximum output power of transmitting link 37dBm, short message transmission success rate 99.5%, packet loss rate ≤0.5%, and can stably achieve bidirectional transmission of 100 characters / time in mountainous scenarios without terrestrial 4G / 5G networks.

[0033] RF Performance: S-parameter test results are shown in Figure 3-6. The reflection coefficient S11 of port 1 (GNSS receive link) is ≤-18dB (1.175GHz); the right-hand circular reflection coefficient S33 of port 3 (short message receive link) is ≤-20dB, and the left-hand circular reflection coefficient is ≤-22dB (1.62GHz); the reflection coefficient S55 of port 5 (short message transmit link) is ≤-19dB (2.49GHz). Antenna gain is shown in Figure 19-22: 3.2dBi gain in the 1.175GHz band, 4.1dBi gain in the 1.575GHz band, 3.8dBi gain in the 1.62GHz band, and 5.3dBi gain in the 2.49GHz band. Aspect ratio is shown in Figure 23-26; the aspect ratio of each operating frequency band is ≤2.8dB, meeting the requirements for circular polarization communication. Antenna efficiency is shown in Figure 27-30; the overall efficiency of each frequency band is ≥82%.

[0034] Environmental adaptability: After extreme temperature cycling test of -40℃ to 85℃ (10 cycles), the performance degradation is ≤3%; after vibration test of 10Hz to 2000Hz (ISO 16750 standard, acceleration 20g), the structure is not loose and the electrical performance is not significantly changed, which meets the automotive-grade reliability requirements.

[0035] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A vehicle-mounted antenna combining GNSS and satellite short message services, comprising a housing consisting of an upper shell (1) and a lower shell (2), characterized in that: It also includes an antenna module (3) disposed within the housing; The antenna module (3) includes a PCB board (31), an antenna (32) disposed above the PCB board (31), and a shield (33) disposed below the PCB board (31). The antenna (32) includes a first antenna (321) operating in the 1.2 GHz band, a second antenna (322) operating in the 1.6 GHz band, and a third antenna (323) operating in the 2.4 GHz band. All three antennas (32) are made of PPO material. The first antenna (321) is used to receive two GNSS signals with a phase difference of 90°. The second antenna (322) is used to receive the 1.6 GHz signal in GNSS and the uplink signal of Beidou short message. The third antenna (323) is used to receive one downlink signal of Beidou short message. The antenna (32) is loaded with T-shaped patches around its perimeter; the T-shaped patches are used to widen the antenna beamwidth and improve the signal coverage in vehicle scenarios. The PCB board (31) is provided with three radio frequency links, namely a GNSS receiving link, a satellite short message receiving link, and a satellite short message transmitting link. The three radio frequency links are respectively connected to the three sets of antennas (32). The PCB board (31) is also connected to a Fakra connector (34).

2. The GNSS and satellite short message combined vehicle-mounted antenna according to claim 1, characterized in that: The GNSS receiving link includes a dual-band pre-filter, a first-stage amplifier, and a second-stage amplifier connected in sequence; the noise figure of the GNSS receiving link is 0.7-1.1dB, and the total gain is not less than 38dB.

3. The GNSS and satellite short message combined vehicle-mounted antenna according to claim 2, characterized in that: The satellite short message receiving link includes a first filter, a third-stage amplifier, a second filter, and a fourth-stage amplifier connected in sequence; the noise figure of the satellite short message receiving link is not higher than 0.8dB, and the total gain is not lower than 36dB.

4. The GNSS and satellite short message combined vehicle-mounted antenna according to claim 1, characterized in that: The satellite short message transmission link includes a third filter, a fifth amplifier, and a sixth amplifier connected in sequence; the maximum output power of the satellite short message transmission link is not less than 36.5dBm, and the total gain is not less than 52dB.

5. A vehicle-mounted antenna combining GNSS and satellite short message communication as described in claim 1, characterized in that: The first antenna (321) and the second antenna (322) adopt a single-layer dual-frequency structure design; the single-layer dual-frequency structure includes an outer square patch and an inner patch, the outer square patch is used to process low-frequency signals, and the inner patch is used to process high-frequency signals.

6. A vehicle-mounted antenna combining GNSS and satellite short message communication as described in claim 1, characterized in that: The third antenna (323) adopts a stacked structure design; the stacked structure is a single-fed right-hand circularly polarized antenna loaded on top of the first antenna, which is used to realize the high-frequency signal transmission of satellite short messages.

7. A vehicle-mounted antenna combining GNSS and satellite short message communication as described in claim 1, characterized in that: The antenna module (3) is provided with metal pillars; the metal pillars are used to isolate the feed points of different frequency bands in the three antenna components to avoid signal interference between frequency bands.

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