A comprehensive navigation system integrating BeiDou front-end and radar front-end

Abstract

This disclosure presents an integrated navigation system combining a BeiDou front-end and a radar front-end, comprising a backplane mechanism; a radar antenna structure mounted in the middle of the backplane mechanism; and a BeiDou antenna structure mounted on the top of the backplane mechanism. Using an exemplary embodiment of this disclosure, supporting foam is added above the BeiDou antenna and the radar antenna to support the metamaterial above the antenna. Because the dielectric constant of the foam is close to that of air, it allows for good matching between the antenna and the metamaterial, enabling the metamaterial to enhance antenna gain and thus improve the overall system's signal reception capability. Alternatively, the antenna itself and the metamaterial can form an integral structure. The exemplary embodiment of this disclosure enables the integration of the BeiDou satellite navigation system and the radar obstacle avoidance system without altering the original navigation radar mechanism, and enhances radar power, giving it a longer detection range.

Description

Technical Field

[0001] This disclosure relates to the field of navigation system technology, specifically to an integrated navigation system that combines BeiDou front-end and radar front-end. Background Technology

[0002] The BeiDou Navigation Satellite System has evolved to BeiDou-3, capable of covering any corner of the globe. However, existing shipborne navigation systems still rely on navigation radar obstacle avoidance and BeiDou positioning, with each system independently inputting its information into the ship's display and control terminal. This is because external BeiDou antennas for marine navigation cannot be integrated inside the radome due to structural and signal strength limitations. Directly miniaturizing the BeiDou receiving antenna and placing it inside the radome would result in weak or nonexistent BeiDou signal reception, preventing the receiver from positioning. Furthermore, modifying the radome's internal structure would sacrifice the original size of the radar transmitting and receiving antennas, leading to insufficient radar power and resolution. Therefore, enhancing signal strength has become a key technology for integrating the two systems. Summary of the Invention

[0003] This disclosure provides an integrated navigation system that combines BeiDou front-end and radar front-end to solve or alleviate the problems in the prior art where directly miniaturizing the BeiDou receiving antenna and placing it inside the radome would result in weak BeiDou receiving signals, insufficient radar power, and insufficient resolution.

[0004] According to one aspect of this disclosure, an integrated navigation system that combines a BeiDou front-end and a radar front-end is provided, including a backplane mechanism; A radar antenna structure is installed in the middle of the backplate mechanism; The top of the backplate mechanism is equipped with a Beidou antenna structure.

[0005] In one possible implementation, the radar antenna structure includes a radar antenna, a radar support foam, and a radar metamaterial; A concave groove is provided in the middle of the back plate mechanism, the radar antenna is installed inside the concave groove, the radar support foam is laid on the surface of the radar antenna, and the radar metamaterial is laid on the surface of the radar support foam.

[0006] In one possible implementation, the radar antenna is an X-band radar array antenna.

[0007] In one possible implementation, the radar antenna is fixed inside the concave groove by screws; The thickness of the radar support foam is 4 mm, and the dielectric constant is 1.07. The radar support foam is glued to the surface of the radar antenna; The radar metamaterial has a thickness of 1.524 mm and a dielectric constant of 3.66.

[0008] In one possible implementation, the BeiDou antenna structure includes a BeiDou cavity, a BeiDou antenna, a BeiDou support foam, and a BeiDou metamaterial. A reflective baffle is installed at the top of the backplate mechanism, the Beidou bottom cavity is installed above the reflective baffle, the Beidou antenna is installed inside the Beidou bottom cavity, the Beidou support foam is laid on the surface of the Beidou antenna, and the Beidou metamaterial is laid on the surface of the Beidou support foam.

[0009] In one possible implementation, the BeiDou antenna is a BeiDou band microstrip antenna.

[0010] In one possible implementation, the BeiDou antenna is fixed to the inside of the BeiDou base cavity by screws; The thickness of the Beidou support foam is 11.82 mm, and the dielectric constant is 1.07. The thickness of the Beidou metamaterial is 1.6 mm, and the dielectric constant is 10. The Beidou metamaterial is bonded to the surface of the Beidou support foam with adhesive.

[0011] In one possible implementation, the design method of the X-band radar array antenna includes: Calculate the wavelength of the microstrip line medium in the X-band radar array antenna based on the frequency and wavelength of the X-band radar electromagnetic waves. The spacing between each antenna element of the X-band radar array antenna is set to one dielectric wavelength.

[0012] The size and number of antenna elements are determined based on the dielectric wavelength and the overall radar structure. The antenna sidelobe level, half-power beamwidth, and current distribution of each antenna element of the X-band radar array antenna are calculated using the Taylor synthesis method. The microstrip line width is calculated from the current distribution, and a feeding network is constructed. The size of the radar array element antenna is calculated based on the frequency range of the X-band radar array antenna. Each branch of the feed network is cascaded to form a linear antenna array, where the spacing between radar array elements in the array is one dielectric wavelength.

[0013] In one possible implementation, the design method of the BeiDou band microstrip antenna includes: The wavelength of the medium is calculated based on the carrier frequency and wave velocity of the BeiDou satellite navigation system. The initial dimensions of the BeiDou band microstrip antenna are calculated based on the dielectric wavelength. A dielectric substrate with a set dielectric constant is selected as the substrate; The patch size of the BeiDou band microstrip antenna is calculated based on the speed of light, the operating frequency of the BeiDou band microstrip antenna, and the dielectric constant of the substrate relative to vacuum. A BeiDou antenna model was created using a computer, and a microstrip antenna for the BeiDou frequency band was designed and optimized using the commercial software HFSS for simulation.

[0014] In one possible implementation, the design method of the BeiDou metamaterial includes: The wavelength of the medium is calculated based on the phase velocity of the BeiDou microstrip line and the BeiDou carrier frequency. The basic model size of the metamaterial unit of Beidou metamaterial is determined based on the dielectric wavelength and the back cavity structure size of the Beidou bottom cavity. The appropriate dielectric material is selected as the substrate material based on the maximum size of the backplane structure of the Beidou bottom cavity and the dielectric wavelength. A regular hexagonal groove and a straight groove are made on a square metal patch to serve as a resonator; The resonant frequency can be adjusted by changing the dimensions of the straight groove, the regular hexagonal groove, and the square metal patch. The S11 and S21 parameters were obtained using computer modeling and simulation. (The S11 and S21 parameters can be directly obtained by establishing a BeiDou metamaterial model using a computer and simulating it using the commercial software HFSS.) The permeability is calculated based on the S11 parameter, S21 parameter, vacuum wavelength, critical wavelength, and reflection coefficient. Then, the dielectric constant is calculated based on the S11 parameter, S21 parameter, vacuum wavelength, critical wavelength, relative permeability, unit cell side length, and transmission coefficient. When the magnetic permeability and dielectric constant are negative at the resonance point in the BeiDou frequency band, the dimensions of the straight groove, the regular hexagonal groove, and the square metal patch are determined, and these are used to determine the dimensions of the BeiDou metamaterial.

[0015] In one possible implementation, the design method of the radar metamaterial includes: Calculate the X-band radar wavelength and dielectric wavelength; Then, based on the dielectric wavelength and the maximum size that the cavity structure can provide, the unit size of the radar metamaterial is determined, and the corresponding dielectric material is selected as the substrate material. The resonant unit is a regular hexagonal microstrip line open loop as the inner ring and a rectangular microstrip line open loop as the outer ring. The resonant frequency in the X-band is adjusted by modifying the spacing of the inner hexagonal ring and the outer rectangular ring, as well as the microstrip linewidth, through computer simulation. The S11 and S21 parameters obtained through simulation, combined with the dielectric constant calculation formula and the permeability calculation formula, show that the permeability µ and dielectric constant ε are negative, thereby determining the size of the metamaterial unit of the radar metamaterial. The metamaterial units of the radar metamaterial are assembled into a metamaterial array, and this array is used as the final size of the radar metamaterial.

[0016] The exemplary embodiments of this disclosure have the following beneficial effects: In the exemplary embodiments of this disclosure, supporting foam is added above the BeiDou antenna and the radar antenna. The supporting foam is used to support the metamaterial above the antenna. Because the dielectric constant of the foam is close to that of air, it can achieve a good match between the antenna and the metamaterial, allowing the metamaterial to enhance the antenna gain, thereby enhancing the overall system's signal reception capability. It can also allow the antenna itself to form an integral structure with the metamaterial. The exemplary embodiments of this disclosure can integrate the BeiDou satellite navigation system and the radar obstacle avoidance system without changing the original navigation radar mechanism, and enhance the radar's power, giving it a longer detection range.

[0017] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features and advantages of this application will become apparent from the accompanying drawings. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit this disclosure. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] Figure 1 This is a cross-sectional view of an integrated navigation system that combines a BeiDou front-end and a radar front-end, according to an exemplary embodiment of this invention. Figure 2 yes Figure 1 Top view of the installation diagram; Figure 3 yes Figure 1 A schematic diagram of the oblique installation; Figure 4 This is a schematic diagram of a BeiDou metamaterial in an integrated navigation system that fuses the BeiDou front-end and radar front-end, according to an exemplary embodiment of this invention. Figure 5 This is a schematic diagram of a radar metamaterial in an integrated navigation system that fuses the BeiDou front-end and the radar front-end, according to an exemplary embodiment of this invention. In the diagram: 1. Backplate mechanism; 2. Radar antenna; 3. Beidou antenna; 4. Beidou support foam; 5. Radar support foam; 6. Beidou bottom cavity; 7. Beidou metamaterial; 8. Radar metamaterial. Detailed Implementation

[0020] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this disclosure more comprehensive and complete, and to fully convey the concept of the example embodiments to those skilled in the art. The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more of the specific details omitted, or other methods, components, apparatus, steps, etc., can be employed. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0021] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware units or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0022] The flowchart shown in the attached diagram is merely an illustrative example and does not necessarily include all steps. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0023] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein.

[0024] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or device that includes a series of steps or sub-modules is not necessarily limited to those steps or sub-modules that are explicitly listed, but may include other steps or sub-modules that are not explicitly listed or that are inherent to such process, method, product, or device.

[0025] like Figure 1-5 As shown, an exemplary embodiment of this disclosure provides an integrated navigation system that integrates a BeiDou front-end and a radar front-end, including: a backplane mechanism 1; A radar antenna structure is installed in the middle of the backplate mechanism 1; The top of the backplate mechanism 1 is equipped with a Beidou antenna structure.

[0026] Specifically, the radar antenna structure includes a radar antenna 2, a radar support foam 5, and a radar metamaterial 8; A concave groove is provided in the middle of the backplate mechanism 1. The radar antenna 2 is installed inside the concave groove. The radar support foam 5 is laid on the surface of the radar antenna 2. The radar metamaterial 8 is laid on the surface of the radar support foam 5.

[0027] Specifically, radar antenna 2 is an X-band radar array antenna.

[0028] In this embodiment, an X-band radar array antenna 2 is installed in the concave groove of the backplate mechanism 1. A supporting foam 5 is covered on the X-band radar array antenna 2, and a specially designed X-band radar metamaterial 8 is covered on the supporting foam 5. A Beidou band microstrip antenna is installed at the upper end of the reflective partition of the backplate mechanism 1, and then further covered with supporting foam, and a specially designed Beidou band metamaterial is covered on the foam.

[0029] It is worth noting that the backplate mechanism 1 is a rod-shaped structure. Specifically, the backplate mechanism 1 includes a base 11, a rod 10, several radar antenna structures, several BeiDou antenna structures, and several reflective baffles. The base is installed at the bottom of the rod, the radar antenna structures and the reflective baffles are installed on the same side of the rod, and each radar antenna structure is installed between two reflective baffles. The BeiDou antenna structures are installed at the top of the rod and above the topmost reflective baffle.

[0030] For example, such as Figure 1 As shown, the backplate mechanism 1 includes four reflective baffles, two sets of radar antenna structures, and one set of BeiDou antenna structures. The four reflective baffles are reflective baffle A, reflective baffle B, reflective baffle C, and reflective baffle D, which are installed on the same side of the backplate mechanism 1 from top to bottom. One set of radar antenna structures is located between reflective baffle D and reflective baffle C; the other set is located between transmitting baffle B and reflective baffle A. The BeiDou antenna structure is installed above transmitting baffle A.

[0031] Specifically, the radar antenna 2 is fixed inside the concave groove by screws; The thickness of radar support foam 5 is 4 mm, and the dielectric constant is 1.07; Radar support foam 5 is glued to the surface of radar antenna 2; The thickness of radar metamaterial 8 is 1.524 mm, and the dielectric constant is 3.66.

[0032] Specifically, the BeiDou antenna structure includes a BeiDou bottom cavity 6, a BeiDou antenna 3, a BeiDou support foam 4, and a BeiDou metamaterial 7; A reflective baffle is installed at the top of the backplate mechanism 1, the Beidou bottom cavity 6 is installed above the reflective baffle, the Beidou antenna 3 is installed inside the Beidou bottom cavity 6, the Beidou support foam 4 is laid on the surface of the Beidou antenna 3, and the Beidou metamaterial 7 is laid on the surface of the Beidou support foam 4.

[0033] Specifically, Beidou antenna 3 is a microstrip antenna for the Beidou frequency band.

[0034] Specifically, the Beidou antenna 3 is fixed to the inside of the Beidou bottom cavity 6 by screws; The thickness of the Beidou support foam 4 is 11.82 mm, and the dielectric constant is 1.07. The thickness of Beidou Metamaterial 7 is 1.6 mm, and its dielectric constant is 10. Beidou metamaterial 7 is bonded to the surface of Beidou support foam 4 with adhesive.

[0035] It is worth noting that the design steps in this embodiment are as follows: Install the X-band radar array antenna 2 and fix the X-band radar array antenna 2 to the back plate mechanism 1 with 16 M2 screws; A 4mm thick supporting foam 5 with a dielectric constant of 1.07 is laid on the X-band radar array antenna 2, and the foam is glued to the top of the microstrip antenna. An X-band radar metamaterial 8 was laid on top of the supporting foam 5. The metamaterial has a dielectric constant of 3.66 and a thickness of 1.524 mm. The Beidou bottom cavity 6 is installed above the reflective baffle A plate of the back plate mechanism 1. The bottom cavity has a height of 10mm. The Beidou bottom cavity and the back plate mechanism 1 are integrated into one piece. The Beidou antenna 3 is installed above the Beidou bottom cavity 9, and the antenna is fixed above the Beidou bottom cavity by four M2 screws; A supporting foam 4 is laid on top of the Beidou antenna 3 and is glued to the Beidou antenna. The supporting foam has a thickness of 11.82mm and a dielectric constant of 1.07. Beidou band metamaterial 7 is laid on top of Beidou support foam 4. The metamaterial is 1.6mm thick and has a dielectric constant of 10. It is bonded to support foam 4 with adhesive.

[0036] Specifically, the design methodology for X-band radar array antennas includes: Calculate the wavelength of the microstrip line medium in the X-band radar array antenna based on the frequency and wavelength of the X-band radar electromagnetic waves. The spacing between each antenna element of the X-band radar array antenna is set to one dielectric wavelength.

[0037] The antenna element size and number of elements are determined based on the dielectric wavelength (e.g., 19.12 mm) and the overall radar structure length (e.g., 382 mm). The sidelobe level (a higher sidelobe level will divert the energy of the main lobe, which is not conducive to the normal transmission or reception of the main lobe), half-power beamwidth (an antenna mode or beam angle in which the relative power is 50% or more of the maximum power, mainly reflecting the energy radiation intensity in a certain direction) and current distribution of each antenna element are calculated according to the Taylor synthesis method. The microstrip line width is calculated from the current distribution, and a feeding network is constructed. The size of the radar array element antenna is calculated based on the frequency range of the X-band radar array antenna. Each branch of the feed network is cascaded to form a linear antenna array, where the spacing between radar array elements in the array is one dielectric wavelength.

[0038] like Figure 1 As shown, this embodiment includes a backplate mechanism 1. An X-band radar array antenna is installed in the groove of the backplate mechanism 1. The radar antenna has a thickness of 0.762 mm, a width of 40 mm, and a length of 385 mm. A radar antenna support foam 5 with a thickness of 4 mm is covered and bonded on top of the installed radar array antenna. A radar metamaterial 8 with a thickness of 1.524 mm is further covered and bonded on top of the radar antenna support foam. A Beidou bottom cavity 9 is installed above the reflector baffle A plate of the backplate mechanism 1. The bottom cavity has a height of 10 mm. The Beidou bottom cavity and the backplate mechanism 1 are integrally processed. A Beidou antenna 3 is installed on top of the Beidou bottom cavity 9. The antenna is fixed on top of the Beidou bottom cavity. A support foam 4 is laid on top of the Beidou antenna 3 and bonded to the Beidou antenna with adhesive. The support foam has a thickness of 11.82 mm and a dielectric constant of 1.07. A Beidou band metamaterial 7 with a thickness of 1.6 mm and a dielectric constant of 10 is laid on top of the Beidou support foam 4 and bonded to the support foam 4 with adhesive.

[0039] Figure 2 As shown, the Beidou metamaterial 7 of this embodiment is reflected in a top view. The Beidou metamaterial is presented in the form of a microstrip resonant circuit. The copper-clad shape at the top exhibits metamaterial properties that do not exist in nature, namely, negative dielectric constant and magnetic permeability. The resonant ring is formed by etching two grooves, a regular hexagonal groove and a straight groove, on the upper copper foil of the dielectric substrate. The inner side-to-side spacing of the groove is 20.8 mm, and the outer side-to-side spacing is 24.2 mm. The two grooves are not connected. Then, a straight groove with a width of 2 mm and a length of 12 mm is etched in the center of the copper foil patch. The final shape of the copper foil is shown in the shaded area in Figure 2.

[0040] like Figure 4As shown in the front view, the overall structure of the radar metamaterial 8 in this embodiment is illustrated. The radar metamaterial 8 is composed of many small resonant units, forming a resonant array. This array is 385 mm long, 40 mm wide, and 1.524 mm thick. Each small resonant unit is as follows... Figure 5 As shown in the diagram, the black shaded area represents the portion where the copper foil is retained, while the rest is composed of composite dielectric material. The resonant unit is as follows: Figure 5 The diagram shows an open rectangular microstrip copper foil containing an open regular hexagonal microstrip copper foil, connected by a metal section.

[0041] Specifically, the design methods for BeiDou band microstrip antennas include: The wavelength of the medium is calculated based on the carrier frequency and wave velocity of the BeiDou satellite navigation system. Calculate the initial dimensions (design dimensions) of the BeiDou band microstrip antenna based on the dielectric wavelength. A dielectric substrate with a set dielectric constant is selected as the substrate; The patch size of the BeiDou band microstrip antenna is calculated based on the speed of light, the operating frequency of the BeiDou band microstrip antenna, and the dielectric constant of the substrate relative to vacuum. A BeiDou antenna model was created using a computer, and a microstrip antenna for the BeiDou frequency band was designed and optimized using the commercial software HFSS for simulation.

[0042] Specifically, the design method of Beidou Metamaterial 7 includes: The wavelength of the medium is calculated based on the phase velocity of the BeiDou microstrip line and the BeiDou carrier frequency. The basic model dimensions of the metamaterial unit of Beidou metamaterial 7 are determined based on the dielectric wavelength and the backplate structure dimensions of Beidou bottom cavity 6. The appropriate dielectric material is selected as the substrate material based on the maximum size of the backplate mechanism of Beidou-6 bottom cavity and the dielectric wavelength. A regular hexagonal groove and a straight groove are made on a square metal patch to serve as a resonator; The resonant frequency can be adjusted by changing the dimensions of the straight groove, the regular hexagonal groove, and the square metal patch. The S11 and S21 parameters were obtained using computer modeling and simulation. (The S11 and S21 parameters can be directly obtained by establishing a BeiDou metamaterial model using a computer and simulating it using the commercial software HFSS.) The permeability is calculated based on the S11 parameter, S21 parameter, vacuum wavelength, critical wavelength, and reflection coefficient. Then, the dielectric constant is calculated based on the S11 parameter, S21 parameter, vacuum wavelength, critical wavelength, relative permeability, unit cell side length, and transmission coefficient. When the magnetic permeability and dielectric constant are negative at the resonance point in the BeiDou frequency band, the dimensions of the straight groove, the regular hexagonal groove, and the square metal patch are determined, and these are used to determine the dimensions of BeiDou metamaterial 7.

[0043] Specifically, the design method of radar metamaterial 8 includes: Calculate the X-band radar wavelength and dielectric wavelength; Then, based on the dielectric wavelength and the maximum size that the cavity structure can provide, the unit size of radar metamaterial 8 is determined, and a corresponding dielectric material is selected as the substrate material. The resonant unit is a regular hexagonal microstrip line open loop as the inner ring and a rectangular microstrip line open loop as the outer ring. The resonant frequency in the X-band is adjusted by modifying the spacing of the inner hexagonal ring and the outer rectangular ring, as well as the microstrip linewidth, through computer simulation. The S11 and S21 parameters obtained through simulation, combined with the dielectric constant calculation formula and the permeability calculation formula, show that the permeability µ and dielectric constant ε are negative, thereby determining the size of the metamaterial unit of the radar metamaterial. The metamaterial units of radar metamaterial 8 are arranged into a metamaterial array, and this array is used as the final size of the radar metamaterial.

[0044] This embodiment is designed in five parts: I. Backplate Mechanism Design: Based on the performance requirements and structural characteristics of the original navigation radar backplane mechanism, a compact and small-sized microstrip navigation antenna structure was selected for integration, and its Beidou cavity and the original radar backplane mechanism were designed as a single unit.

[0045] II. X-band radar array antenna design: Formula for the relationship between electromagnetic wave frequency and wavelength In the formula Indicates the wavelength of the medium. Indicates the phase velocity of the microstrip line. If the frequency is used to calculate the wavelength of the microstrip line medium, then the spacing between each antenna element is approximately one medium wavelength.

[0046] The size and number of antenna elements are determined based on the dielectric wavelength and the overall radar structure. Then, refer to the Taylor synthesis method to calculate the corresponding antenna sidelobe level, half-power beamwidth, and current distribution of each antenna element; The microstrip line width is calculated from the current distribution, and a feeding network is constructed. Then, the size of the unit antenna is calculated based on the radar antenna frequency range; Each branch of the feed network is cascaded to form a linear antenna array, where the spacing between radar array elements in the array is one dielectric wavelength.

[0047] III. BeiDou Antenna Design: Microstrip patches are known to be compact, thin, and inexpensive, while maintaining a planar dimension roughly the size of a single patch, with only a slight increase in thickness. This invention requires the miniaturization of the BeiDou system, and therefore utilizes microstrip antenna technology to achieve this miniaturization. Thus, a microstrip design approach is employed.

[0048] Based on the relationship between frequency and wave speed In the formula Indicates the wavelength of the medium. Indicates the phase velocity of the microstrip line. The wavelength of the medium is calculated from the frequency. Evaluate the initial antenna dimensions based on the dielectric wavelength; To further reduce the area, Tecumseh CER-10 dielectric substrate with a higher dielectric constant was selected as the substrate. Further from the formula In the formula The side length of the antenna patch. Represents the speed of light. Indicates the antenna's operating frequency. The patch size is calculated using the dielectric constant of the substrate material relative to vacuum. The BeiDou microstrip antenna was further optimized and designed through computer simulation.

[0049] IV. BeiDou Metamaterial Design: Firstly, through In the formula Indicates the wavelength of the medium. Indicates the phase velocity of the microstrip line. Frequency is used to calculate the wavelength of the medium; The basic model dimensions of the metamaterial unit are further determined based on the dielectric wavelength and the dimensions of the back cavity mechanism; Furthermore, based on the maximum size that the back cavity mechanism can provide and the dielectric wavelength, the appropriate dielectric material, Tecumseh CER-10, is selected as the substrate material. Furthermore, metal patches with hexagonal and linear grooves are used as resonators; The resonant frequency can be further adjusted by modifying the dimensions of the straight groove, the regular hexagonal groove, and the square metal patch. The parameters S11 and S21 were obtained using computer simulation. Based on the S-parameters, which represent scattering parameters and describe the frequency domain characteristics of the transmission channel, S11 represents return loss, and S21 represents insertion loss, expressed by the formula... and In the formula Vacuum wavelength, This is the critical wavelength. The reflection coefficient, , The permeability µ is obtained; Then, based on the S-parameters, use the formula... and In the formula Vacuum wavelength, This is the critical wavelength. Relative permeability, Let be the side length of the unit. The dielectric constant ε is derived from the transmission coefficient; When the magnetic permeability µ and dielectric constant ε are negative at the resonance point in the BeiDou frequency band, the dimensions of the straight groove, the regular hexagonal groove, and the square metal patch are determined, and these are used to determine the dimensions of the BeiDou metamaterial.

[0050] This design allows the antenna gain of the BeiDou band signal to be increased by about 1.5-1.7 times after passing through this metamaterial.

[0051] V. Radar Metamaterial Design: Similar to Beidou metamaterials, and Calculate the wavelength and the wavelength of the medium; Then, based on the dielectric wavelength and the maximum size that the cavity mechanism can provide, the unit size of the metamaterial is determined, and Rogers R04350, the corresponding dielectric material, is selected as the substrate material. Furthermore, a regular hexagonal microstrip line open-loop ring is used as the inner ring and a rectangular microstrip line open-loop ring is used as the outer ring as the resonant unit; Further adjustments to the spacing of the inner hexagonal ring and the outer rectangular ring, as well as the microstrip linewidth, were made using computer simulation to adjust the resonant frequency in the X-band. The S-parameters obtained through simulation represent scattering parameters, describing the frequency domain characteristics of the transmission channel. S11 represents the return loss, and S21 represents the insertion loss. The calculation formulas for the dielectric constant are as follows: In the formula Vacuum wavelength, This is the critical wavelength. Relative permeability, Let be the side length of the unit. Formulas for calculating transmission coefficient and permeability In the formula Vacuum wavelength, This is the critical wavelength. The reflection coefficient, , Let be the side length of the unit. The permeability µ and dielectric constant ε derived from the transmission coefficient are negative. This determines the size of the metamaterial unit.

[0052] Furthermore, the metamaterial units are arranged into a metamaterial array, namely a 5*48 array, which serves as the final size of the radar metamaterial.

[0053] This design allows radar X-band signals to gain by approximately 1.5-1.7 times after passing through this metamaterial.

[0054] After determining the implementation method of the entire system, and with the aim of improving the signal reception capability of BeiDou satellite navigation and radar while simplifying the structure, supporting foam was added above the BeiDou antenna and radar antenna. This supporting foam supports the metamaterial above the antenna. Because the dielectric constant of foam is close to that of air, it allows for a good match between the antenna and the metamaterial, enabling the metamaterial to enhance antenna gain and thus improve the overall system's signal reception capability. It also allows the antenna itself to form an integral structure with the metamaterial.

[0055] The above are merely preferred embodiments of this disclosure. The scope of protection of this disclosure is not limited to the above embodiments. All technical solutions falling within the scope of this disclosure are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of this disclosure should be considered within the scope of protection of this disclosure.

Claims

1. A comprehensive navigation system integrating BeiDou front-end and radar front-end, characterized in that, It includes a backplate mechanism (1); a radar antenna structure is installed in the middle of the backplate mechanism (1); and a Beidou antenna structure is installed on the top of the backplate mechanism (1). The radar antenna structure includes a radar antenna (2), a radar support foam (5), and a radar metamaterial (8); a concave groove is provided in the middle of the back plate mechanism (1), the radar antenna (2) is installed inside the concave groove, the radar support foam (5) is laid on the surface of the radar antenna (2), and the radar metamaterial (8) is laid on the surface of the radar support foam (5). The Beidou antenna structure includes a Beidou cavity (6), a Beidou antenna (3), a Beidou support foam (4), and a Beidou metamaterial (7); a reflective baffle is installed at the top of the backplate mechanism (1), the Beidou cavity (6) is installed above the reflective baffle, the Beidou antenna (3) is installed inside the Beidou cavity (6), the Beidou support foam (4) is laid on the surface of the Beidou antenna (3), and the Beidou metamaterial (7) is laid on the surface of the Beidou support foam (4); The radar antenna (2) is an X-band radar array antenna; the radar antenna (2) is fixed inside the concave groove by screws; the radar support foam (5) has a thickness of 4 mm and a dielectric constant of 1.07; the radar support foam (5) is glued to the surface of the radar antenna (2); the radar metamaterial (8) has a thickness of 1.524 mm and a dielectric constant of 3.66; The Beidou antenna (3) is fixed inside the Beidou bottom cavity (6) by screws; the thickness of the Beidou support foam (4) is 11.82 mm and the dielectric constant is 1.07; the thickness of the Beidou metamaterial (7) is 1.6 mm and the dielectric constant is 10; the Beidou metamaterial (7) is glued to the surface of the Beidou support foam (4).

2. The integrated navigation system combining BeiDou front-end and radar front-end as described in claim 1, characterized in that, The Beidou antenna (3) is a microstrip antenna in the Beidou frequency band.

3. The integrated navigation system combining BeiDou front-end and radar front-end according to claim 1, characterized in that, The design method for the X-band radar array antenna includes: calculating the microstrip line dielectric wavelength in the X-band radar array antenna based on the frequency and wavelength of the X-band radar electromagnetic wave; setting the spacing between each antenna element of the X-band radar array antenna to one dielectric wavelength; determining the antenna element size and number of elements based on the dielectric wavelength and the overall radar structure length; calculating the antenna sidelobe level, half-power beamwidth, and current distribution of each antenna element using the Taylor synthesis method; calculating the microstrip line width from the current distribution and forming a feed network; calculating the size of the radar array element antenna based on the frequency range of the X-band radar array antenna; and cascading each branch of the feed network to form a linear antenna array, wherein the spacing between radar array elements in the array is one dielectric wavelength.

4. The integrated navigation system combining BeiDou front-end and radar front-end according to claim 2, characterized in that, The design method for the BeiDou band microstrip antenna includes: calculating the dielectric wavelength based on the BeiDou satellite navigation carrier frequency and wave velocity; calculating the initial dimensions of the BeiDou band microstrip antenna based on the dielectric wavelength; selecting a dielectric substrate with a set dielectric constant as the substrate; calculating the patch dimensions of the BeiDou band microstrip antenna based on the speed of light, the operating frequency of the BeiDou band microstrip antenna, and the dielectric constant of the substrate relative to vacuum; and establishing a BeiDou antenna model using a computer and simulating and optimizing the design of the BeiDou band microstrip antenna.

5. The integrated navigation system combining BeiDou front-end and radar front-end according to claim 1, characterized in that, The design method of the Beidou metamaterial (7) includes: calculating the dielectric wavelength based on the phase velocity of the Beidou microstrip line and the Beidou carrier frequency; determining the metamaterial unit model size of the Beidou metamaterial (7) based on the dielectric wavelength and the backplate mechanism size of the Beidou cavity (6); selecting the appropriate dielectric material as the substrate material based on the maximum size of the backplate mechanism of the Beidou cavity (6) combined with the dielectric wavelength; opening a regular hexagonal groove and a straight groove on the square metal patch as a resonator; adjusting the size of the straight groove, the regular hexagonal groove and the square metal patch... The resonant frequency is adjusted by adjusting the size; the S11 and S21 parameters are obtained by computer modeling and simulation; the permeability is calculated based on the S11 and S21 parameters, vacuum wavelength, critical wavelength and reflection coefficient; the dielectric constant is calculated based on the S11 and S21 parameters, vacuum wavelength, critical wavelength, relative permeability, unit side length and transmission coefficient; when the resonant frequency is in the Beidou band and the permeability and dielectric constant are negative, the size of the straight groove, the regular hexagonal groove and the square metal patch are determined, and the size of the Beidou metamaterial (7) is determined accordingly.

6. The integrated navigation system combining BeiDou front-end and radar front-end according to claim 1, characterized in that, The design method of the radar metamaterial (8) includes: calculating the X-band radar wavelength and dielectric wavelength; determining the unit size of the radar metamaterial (8) based on the dielectric wavelength and the maximum size that the back cavity mechanism can provide, and selecting the corresponding dielectric material as the substrate material; using a regular hexagonal microstrip line open ring as the inner ring and a rectangular microstrip line open ring as the outer ring as the resonant unit; adjusting the spacing of the regular hexagonal inner ring and the rectangular outer ring and the microstrip linewidth through computer simulation to adjust the resonant frequency in the X-band; and using the S11 and S21 parameters obtained from the simulation, combined with the dielectric constant calculation formula and the permeability calculation formula, determining that the permeability μ and dielectric constant ε are negative, thereby determining the size of the metamaterial unit of the radar metamaterial; assembling the metamaterial units of the radar metamaterial (8) into a metamaterial array, and using this array as the final size of the radar metamaterial.

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