Beidou multi-mode timing receiver

Abstract

The Beidou multi-mode timing receiving device is composed of a multi-mode broadband timing antenna and a multi-mode baseband demodulation module, wherein the multi-mode broadband timing antenna includes a broadband ceramic dielectric circularly polarized antenna or a multi-mode antenna combination device, a pre-bandpass filter, a low-noise field effect amplifier, a broadband bandpass filter, a monolithic low-noise amplifier, a lightning surge voltage impact circuit, a power supply voltage stabilization circuit, and a hemispherical omnidirectional fixing device. The device can receive Beidou-3 and GPS, Galileo, QZSS, IRNSS, or GLONASS satellite navigation timing carrier signals in multiple modes. In order to adapt to the changes in the Beidou navigation satellite broadcasting system, a new multi-mode antenna combination method is adopted, and the broadcast is carried out in an inclined geostationary orbit according to the B1I and B1C frequency bands. A satellite addressing fixed structure is specially configured and a multi-mode baseband demodulation module is used in conjunction to ensure that the existing timing base station can simultaneously receive different satellite navigation timing signals, strive to get rid of the dependence on the GPS single satellite navigation system, and improve the safety, reliability and autonomy of my country's mobile communication and power network timing. The present invention belongs to the field of satellite navigation timing.

Description

Technical Field

[0001] The present invention relates to a Beidou multi-mode timing receiving device, which is particularly suitable for timing synchronization of mobile communication stations and power networks, and is applied to new generation mobile communication and positioning navigation devices, and belongs to the field of satellite positioning, navigation and timing. Background Art

[0002] It has become a consensus in the GNSS community to establish compatible satellite navigation and timing receiving equipment. With the establishment of the BeiDou-3 satellite navigation system, Chinese companies specializing in the manufacture of satellite navigation semiconductor devices have successively developed RF baseband integrated demodulation chips that are mainly based on BeiDou-3 and compatible with other GNSS navigation systems, laying the foundation for my country to develop various satellite navigation application products. However, the production of compatible satellite navigation and timing receiving devices requires not only a breakthrough in multi-mode RF baseband integrated demodulation chips, but also the coupling connection between multi-mode satellite receiving antennas and baseband chips. Prior to this, the compatible timing and navigation test equipment developed by Trimble (Tianbao) in the United States and NovAtel in Sweden mainly used independent GPS and GLONASS single-frequency antennas for combination, or designed as a large multi-mode metal antenna coupled with an RF amplifier. After my country's BeiDou-2 took priority in occupying the 1561.098MHz civilian frequency, the inventor first proposed the development of a miniature planar broadband ceramic dielectric antenna based on the principle of dual-peak broadband RF reception, achieving dual-mode reception of the BeiDou-2 B1 frequency 1561.098 and the 1575.42MHz civilian frequency shared by GPS and GALILEO, and successfully tested it in a mobile base station. The technology was also written into patent document 200810080082.X, and the GLONASS civilian frequency was subsequently included in patent 200910073942.1, striving to achieve multi-mode reception of civilian open signals of the GNSS navigation system. However, according to the BeiDou-3 interface control document released by the China Satellite Navigation System Management Office in November 2017, the BeiDou navigation satellite system has undergone major adjustments. The newly established B1C signal of BeiDou-3 will be broadcast on medium earth orbit (MEO) satellites and inclined geosynchronous orbit (IGSO) satellites. Its carrier frequency will share the 1575.42MHz frequency of the US GPS. Its bandwidth is clearly 32.736MHz, and it will be modulated using the BOC (1.1) binary offset carrier technology. See Table 1.

[0003] Table 1. B1C signal structure

[0004]

[0005] At the same time, the B1I frequency was announced as 1561.098MHz, but it was clearly not broadcast on medium earth orbit (MEO) satellites. This is a big change, which means that domestic ground navigation and timing equipment developed for the B1 frequency must make adaptive improvements to their products. In addition, the recently released draft of the national standard for comments also made new regulations on the compatibility of measurement receivers and put forward higher requirements for measurement receiving antennas. See Table 2 and Table 3 and the figure.

[0006] Table 2. Channel numbers and tracking capabilities of GNSS measurement receivers

[0007] Receiver category Frequency points Minimum system components Number of channels Single mode single frequency ≥1 BDS ≥12 Multimode single frequency ≥2 BDS+(GPS / GLONASS / Galileo) ≥24 Single Mode Multi-Frequency ≥2 BDS ≥24 Multi-mode and multi-frequency ≥4 BDS+(GPS / GLONASS / Galileo) ≥48 All-constellation multi-frequency ≥8 BDS+GPS+GLONASS+Galileo ≥96

[0008] Table 3. Center frequency, code rate, bandwidth and modulation method of each frequency point signal of GNSS navigation system

[0009]

[0010] Although the broadband timing active antenna technology used in the inventor's patent 200910073942.1 is designed to be compatible with the B1 of BeiDou-2 and the L1 frequency of GPS, it can still meet the requirements of receiving the new carriers broadcast by B1I and B1C of BeiDou-3 in geostationary orbit due to its wide receiving frequency band. However, in order to receive most GNSS satellite navigation signals with high quality, it must be adjusted according to the new BeiDou system. In particular, the spectrum of B1C is composed of offset carriers. Whether the upper and lower sideband signals can be fully received becomes the key to ensuring the demodulation accuracy. Therefore, it is necessary to improve and perfect the existing multi-mode timing active antenna. In particular, the B1I signal broadcast by BeiDou-3 is broadcast on geostationary satellites, which objectively requires that the ground receiving antenna should have hemispherical omnidirectional addressing function, and the fixed structure involved should also be changed accordingly. Summary of the invention

[0011] The problem to be solved by the present invention is to comprehensively design a timing receiving device that is mainly based on the Beidou-3 satellite navigation system and is compatible with multiple modes and systems, to ensure that the existing timing base station can simultaneously receive different satellite navigation timing signals, and strive to get rid of the dependence on the GPS single satellite navigation system, and to improve the security, reliability and autonomy of my country's mobile communications and power network systems.

[0012] The Beidou multi-mode timing receiving device of the present invention is composed of a multi-mode broadband timing active antenna and a multi-mode baseband demodulation module, and is characterized in that: the multi-mode broadband timing active antenna comprises a broadband ceramic dielectric circularly polarized antenna or a multi-mode antenna combination device, a pre-bandpass filter, a low-noise field effect amplifier, a broadband bandpass filter, a monolithic low-noise amplifier, a lightning surge voltage impact protection circuit, a power supply voltage stabilization circuit, a printed circuit board containing a microstrip circuit, a non-standard N-type pin-type connecting rod electrical connector, an antenna housing, and a unidirectional or hemispherical omnidirectional fixing device; the broadband ceramic dielectric circularly polarized antenna or the multi-mode antenna combination device can simultaneously receive Beidou-3 and GPS, Galileo, QZSS, IRNSS, or GLONASS satellite navigation timing carrier signals, and receive The frequencies are 1561.098MHz for BeiDou-3 B1I and 1575.42MHz for BeiDou-3 B1C to share frequencies with GPS, Galileo, etc.; or extended to 1602.56MHz for GLONASS; or can cover military and civilian frequency bands such as BeiDou-3 B2\B3, GPS L2\L5, Galileo E5A\E5B, E6, and GLONASS G2\G3; the broadband ceramic dielectric circularly polarized antenna or multi-mode antenna combination device is arranged on one side of the printed circuit board and connected to the input end of the front-end bandpass filter on the other side through a lead; or a single-mode single-frequency broadband ceramic dielectric antenna is arranged to specifically receive the carrier signal broadcast by B1C or B3I on the medium circular orbit satellite;

[0013] The above-mentioned broadband bandpass filter adopts ceramic dielectric or surface acoustic wave filter, and the selectable frequency response bandwidth is 1166-1217MHz; or 1250-1286MHz; or 1550-1595MHz, or up to 1620MHz according to the compatible mode; when single-mode single-frequency is adopted to receive B1C carrier signal, the frequency response bandwidth of the ceramic dielectric or surface acoustic wave filter should be selected as 1558-1592MHz to ensure that the upper and lower sideband signals modulated by BOC technology are fully received, and at the same time, it is compatible with frequency sharing signals such as GPS and Galileo;

[0014] The main technical parameters of the multi-mode broadband timing active antenna are as follows:

[0015] (1) Frequency range [MHz]: 1166-1217 MHz; or 1250-1286 MHz;

[0016] or 1550-1595MHz; or extended to 1620MHz; or 1558-1592MHz

[0017] (2) Gain [dBi]: > 20

[0018] (3) Noise coefficient [dB]: <2.5@+25℃, <3.0@+80℃

[0019] (4) Out-of-band suppression [dB]: fo = 1190 MHz; or fo = 1268 MHz;

[0020] or fo=1570MHz; or fo=1575MHz; or fo=1585MHz

[0021] fo±30MHz>5

[0022] fo±50MHz>20

[0023] fo±100MHz>50

[0024] (5) Input and output voltage standing wave ratio: ≤2.0

[0025] (6) Surge (impact) immunity performance complies with

[0026] IEC 61000-4-5:1995 standard; GB / T 17626.5-2008 standard

[0027] Surge waveform: CWG combination wave, 1.2 / 50μs, 8 / 20μs

[0028] Voltage peak value [V]: ≥ 2000

[0029] Number of pulses: 10

[0030] (7) Signal delay is less than 5ns;

[0031] The above-mentioned broadband ceramic dielectric circularly polarized antenna is designed and manufactured with a planar structure, or with a cylindrical spiral structure, and is a single-arm, two-arm, or four-arm spiral ceramic dielectric circularly polarized antenna; a planar broadband ceramic circularly polarized antenna and a single-frequency spiral ceramic circularly polarized antenna with a GLONASS center frequency of 1602.56MHz can also be selected to be combined at the same time; a planar broadband ceramic structure is preferably selected for receiving the 1575.42MHz frequency shared by BeiDou-3 B1I and B1C with GPS and Galileo, or a B1C, B3I single-mode single-frequency antenna; a full-frequency multi-mode receiving antenna is preferably selected with a spiral broadband ceramic structure, or a multi-layer superimposed planar and spiral ceramic dielectric circularly polarized antenna;

[0032] The above-mentioned pre-bandpass filter, low-noise field effect amplifier, broadband bandpass filter, monolithic low-noise amplifier, lightning protection surge voltage impact circuit and power supply voltage stabilization circuit are located on the other side of the printed circuit board; the above circuits are arranged in a metal shielding cavity; the lightning protection surge voltage impact circuit should not select gas lightning protection components, and only unidirectional TVS tubes with excellent switching characteristics and withstand voltage characteristics can be selected, also known as transient voltage suppression diodes. The diode can be connected to the ground in reverse before the power supply voltage stabilization circuit to undertake lightning protection and anti-static tasks. In order to improve the insurance coefficient, two diodes should be set, or one can be set; the reason is that the gas discharge element adopts the glow discharge principle to unload, but at the same time, irregular instantaneous high-voltage spike pulses will inevitably be generated at both ends of the discharge device, and the pulses can cause serious damage to the low-noise device;

[0033] The antenna shell is divided into a shell cover and a shell, the printed circuit board is installed in the shell, the carrier output lead is connected to the non-standard N-type pin-type connecting rod electrical connector, and the non-standard N-type pin-type connecting rod electrical connector is fixed or embedded in the shell; the bottom of the shell is a plane fixing structure, and a fixing nut is embedded in the bottom fixing hole, so that the bottom plane of the antenna shell and the metal plane fixing device are fastened with screws; or a traditional bottom spiral groove fixing structure is adopted, and the bottom of the shell is fixed to an external plane metal fixing device through a fixing hole; the shell cover and the shell are hermetically sealed;

[0034] The above-mentioned unidirectional or hemispherical omnidirectional fixtures are designed for tracking navigation satellites. The unidirectional fixture requires that the top of the antenna be installed toward the zenith, which is suitable for receiving the BeiDou-3 medium earth orbit (MEO) B1C signal and other shared satellite frequency band signals; the hemispherical omnidirectional fixture requires that the antenna can be turned horizontally 180 degrees to the left and right, and can also be tilted forward 90 degrees, so that the timing active antenna can accurately face the BeiDou navigation inclined geosynchronous orbit (IGSO) satellite or geostationary synchronous orbit (GEO) satellite; the antenna is tightened at the point with the maximum receiving gain after the azimuth adjustment test;

[0035] The above-mentioned hemispherical omnidirectional fixing device is a necessary measure taken for the new Beidou-3 satellite broadcasting system. The hemispherical omnidirectional fixing device can have a variety of structural options, such as imitating the addressing fixing structure of a satellite TV antenna. The present invention fixes the Beidou multi-mode timing active antenna on a flat base metal fixing plate according to the bottom plane structure of the antenna shell by fastening nuts. The extended part of the metal plate is bent, and a rotation axis fixing hole and a bendable and slidable guide hole are set at the bent part to tilt and turn up and down by 90 degrees. Correspondingly, a metal plate that can be fixed to a pole is configured, and two rotation axis fixing holes are set at one end of the plate surface corresponding to the base metal fixing plate so as to adjust the azimuth angle and fix the whole body. The other end of the metal fixing plate is a bilaterally symmetrical pole structure, which is fastened to the pole with four screws.

[0036] The above-mentioned multi-mode antenna combination device selectively combines a broadband ceramic dielectric antenna or a single-frequency ceramic dielectric antenna including a planar or spiral structure antenna according to the use environment, and fixes them on the copper-clad printed circuit board by stacking them up and down or splitting them in a plane to ensure high-quality reception of navigation and timing signals broadcast by navigation satellites; or sets a single-mode single-frequency or single-mode multi-frequency broadband ceramic dielectric antenna according to national standards, such as selecting a single-frequency ceramic dielectric antenna according to the Beidou B2a and B3I radio frequency specifications, and selecting a corresponding bandpass filter according to the carrier bandwidth to meet the special needs of users.

[0037] The multi-mode baseband demodulation module is commonly known as an OEM demodulation board, and includes a multi-mode ceramic dielectric power divider, a ceramic dielectric or surface acoustic wave filter, and a baseband demodulation module, which are installed and mounted on a printed circuit board; it is characterized in that: the input end of the multi-mode ceramic dielectric power divider is connected to the high-frequency carrier signal from the Beidou multi-mode timing active antenna, and the output end is respectively connected to the three frequency points of B1I, B1C, or GLONASS, or the special ceramic dielectric or surface acoustic wave filter belonging to the B2a and B3I frequency points, the output end of the ceramic dielectric or surface acoustic wave filter is respectively connected to the input end of the baseband demodulation module, and the main and standby signals of the timing are specified by software compilation, and the output is a 1PPS second pulse with an error of less than 50ns, which is used for mobile base stations or power network benchmark timing.

[0038] The advantage of the present invention is that the device fully takes into account the major changes in the Beidou navigation system and the Beidou-3 satellite broadcast signals, and takes into account the reception of medium-earth low-orbit satellite signals while taking into account the reception of geostationary orbit satellite signals. The device is particularly suitable for mobile base station timing and power network timing. The inventor's patent 200910073942.1 is incorporated into the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the principle of the Beidou multi-mode timing active antenna of the present invention.

[0040] Figure 2 This is a schematic diagram of the overall structure of the Beidou multi-mode timing active antenna of the present invention.

[0041] Figure 3 This is a schematic diagram of the broadband ceramic antenna superposition combination of the present invention

[0042] (1) Planar ceramic antenna superposition combination

[0043] (2) Combination of planar and spiral ceramic antennas

[0044] Figure 4 This is a schematic diagram of the split combination of the planar and spiral ceramic antennas of the present invention.

[0045] Figure 5This is a schematic diagram of the omnidirectional addressing fixed structure of the timing active antenna of the present invention.

[0046] Figure 6 This is a schematic diagram of the lightning protection circuit principle and TVS tube characteristics of the present invention.

[0047] Figure 7 This is a schematic diagram of the multi-mode baseband demodulation module of the present invention.

[0048] Figure 8 This is the current RF frequency distribution map of Beidou navigation satellite

[0049] Among them: 1. broadband ceramic dielectric circularly polarized antenna or antenna combination device, 2. pre-bandpass filter, 3. low noise field effect amplifier, 4. broadband bandpass filter, 5. monolithic low noise amplifier, 6. lightning surge voltage impact protection circuit, 7. power supply voltage stabilization circuit, 8. double-sided printed copper clad board containing microstrip circuit, 9. non-standard N-type pin connecting rod electrical connector, 10. shielding cover, 11. antenna shell cover, 12. antenna shell, 13. hemispherical omnidirectional fixing device, 14. fastening nut, 15. coaxial cable, 16. planar broadband ceramic dielectric antenna, 17. single-frequency spiral ceramic dielectric antenna, 18. unidirectional TVS tube, 19. guide hole, 20. pole, 21. multi-mode ceramic dielectric power divider, 22. ceramic dielectric or surface acoustic wave filter, 23. baseband demodulation module DETAILED DESCRIPTION

[0050] Beidou multi-mode timing active antenna structure Figure 1 As shown, the composite navigation signal is received by a broadband ceramic dielectric antenna 1 and connected to the input end of a low noise amplifier 3 through a pre-bandpass filter 2, the output end of the low noise field effect amplifier 3 is connected to a broadband bandpass filter 4, and then connected to the input end of a non-standard N-type pin-type connecting rod electrical connector 9 through a coaxial cable 15 via a monolithic low noise amplifier 5, and the N-type end of 9 is connected to a baseband timing decoding system through the coaxial cable 15, forming a low noise high frequency RF amplification receiving link; the lightning surge voltage impact protection circuit 6 and the power supply stabilizing circuit 7 ensure power supply on the one hand, and prevent harmful electrical pulses from damaging low noise devices through the power supply circuit.

[0051] In order to cover the civil frequency band signals broadcast by Beidou satellites, the antenna combination device can select a planar broadband ceramic dielectric antenna 16 and a planar single-frequency ceramic dielectric antenna 17 in an up-and-down stacked combination, or select a planar broadband ceramic dielectric antenna 16 and a single-frequency spiral ceramic dielectric antenna 17 in a separate combination, or select a broadband spiral ceramic dielectric antenna 17 and a planar single-frequency ceramic dielectric antenna combination, and the combined antenna lead is connected to the input end of the pre-bandpass filter.

[0052] The hemispherical omnidirectional fixing device 13 is a necessary means to adapt to the new broadcasting system of the Beidou-3 satellite. The hemispherical omnidirectional fixing device 13 can have a variety of structural options, such as an addressable fixing structure for a satellite TV antenna. The present invention is based on the plane structure of the bottom of the antenna shell, and is fixed to a flat metal fixing plate by a fastening nut 14. The extended part of the metal plate is bent, and a rotating shaft fixing hole and a curved slidable guide hole 19 are set in the bent part to tilt and turn up and down by 90 degrees. Correspondingly, the metal plate needs to be fixed to the holding pole 20, and two rotating shaft fixing holes are set on one side of the plate surface to fix the timing antenna after addressing as a whole. The other side is a double-sided metal holding pole structure, which is fastened to the holding pole 20 with four screws.

[0053] The multi-mode baseband demodulation module, commonly known as the OEM demodulation board, is equipped with a multi-mode ceramic dielectric power divider 21. The input end is connected to the high-frequency carrier signal from the Beidou multi-mode timing active antenna, and the output end is connected to the ceramic dielectric or surface acoustic wave filter 22 belonging to the three frequency points of B1I, B1C, or GLONASS, or the B2a and B3I frequency points. Then, they are connected to the input end of the baseband demodulation module 23 respectively. The main and standby timing signals are specified through software compilation. The output is a 1PPS second pulse with an error of less than 50ns, which is used for mobile base stations or power reference timing.

Claims

1. The Beidou multi-mode timing receiving device consists of a multi-mode broadband timing active antenna and a multi-mode baseband demodulation module, and is characterized by: The multi-mode broadband timing active antenna comprises a broadband ceramic dielectric circularly polarized antenna or a multi-mode antenna combination device, a front bandpass filter, a low-noise field effect amplifier, a broadband bandpass filter, a monolithic low-noise amplifier, a lightning surge voltage impact protection circuit, a power supply stabilizing circuit, a printed circuit board containing a microstrip circuit, a non-standard N-type pin-type connecting rod electrical connector, an antenna housing, and a hemispherical omnidirectional fixing device; the broadband ceramic dielectric circularly polarized antenna or the multi-mode antenna combination device can simultaneously receive Beidou-3 and GPS, Galileo, QZSS, IRNSS, GLONASS satellite navigation timing carrier signals, and the receiving frequencies are 1561.0 of Beidou-3 B1I and 1561.0 of Beidou-3 B1I. 98MHz and 1575.42MHz for BeiDou-3 B1C to realize frequency sharing with GPS and Galileo; 1602.56MHz for GLONASS; it can cover the military and civilian frequency bands of BeiDou-3 B2\B3, GPS L2\L5, Galileo E5A\E5B, E6, and GLONASS G2\G3; the broadband ceramic dielectric circularly polarized antenna or multi-mode antenna combination device is arranged on one side of the printed circuit board and connected to the input end of the front bandpass filter on the other side through a lead; or a single-mode single-frequency broadband ceramic dielectric antenna is arranged to specifically receive the carrier signal broadcast by B1C or B3I in the medium circular orbit satellite; 1) The above-mentioned broadband bandpass filter adopts ceramic dielectric or surface acoustic wave filter, and the selectable frequency response bandwidth is 1166-1217MHz; or 1250-1286MHz; or 1550-1595MHz, or up to 1620MHz according to the compatible mode; when single-mode single-frequency is used to receive B1C carrier signal, the frequency response bandwidth of the ceramic dielectric or surface acoustic wave filter is selected to be 1558-1592MHz, ensuring that the upper and lower sideband signals modulated by BOC technology are fully received, and compatible with GPS and Galileo frequency sharing signals; 2) The main technical parameters of the multi-mode broadband timing active antenna are as follows: 3) The above-mentioned broadband ceramic dielectric circularly polarized antenna is designed and manufactured with a planar structure, or a cylindrical spiral structure, and is a single-arm, two-arm, or four-arm spiral ceramic dielectric circularly polarized antenna; or a planar broadband ceramic circularly polarized antenna is selected to be combined with a single-frequency spiral ceramic circularly polarized antenna with a GLONASS center frequency of 1602.56MHz; a planar broadband ceramic structure is selected to receive the 1575.42MHz frequency shared by BeiDou-3 B1I and B1C with GPS and Galileo, or a B1C, B3I single-mode single-frequency antenna; the full-frequency multi-mode receiving antenna is a spiral broadband ceramic structure, or a multi-layer superimposed planar and spiral ceramic dielectric circularly polarized antenna; 4) The above-mentioned pre-bandpass filter, low-noise field effect amplifier, broadband bandpass filter, monolithic low-noise amplifier, lightning protection surge voltage impact circuit and power supply voltage stabilization circuit are located on the other side of the printed circuit board; the above circuits are arranged in a metal shielding cavity; the lightning protection surge voltage impact circuit selects a unidirectional TVS tube with excellent switching characteristics and withstand voltage characteristics, also known as a transient voltage suppression diode, and the diode is reversely connected to the ground before the power supply voltage stabilization circuit to undertake the lightning protection and anti-static tasks, and two or one can be set; 5) The antenna housing is divided into a shell cover and a shell, the printed circuit board is installed in the shell, the carrier output lead is connected to the non-standard N-type pin-type connecting rod electrical connector, and the non-standard N-type pin-type connecting rod electrical connector is fixed or embedded in the shell; the bottom of the shell is a plane fixing structure, and a fixing nut is embedded in the bottom fixing hole, so that the bottom plane of the antenna shell and the metal plane fixing device are fastened with screws; or a traditional bottom spiral groove fixing structure is adopted, and the bottom of the shell is fixed to an external plane metal fixing device through a fixing hole; the shell cover and the shell are hermetically sealed; 6) The hemispherical omnidirectional fixture requires the antenna to be able to turn horizontally 180 degrees to the left and right, and tilt forward 90 degrees, so that the timing active antenna can accurately face the Beidou navigation tilt geosynchronous orbit (IGSO) satellite or geostationary synchronous orbit (GEO) satellite; the antenna is tightened at the point with the maximum receiving gain after the azimuth adjustment test; 7) The bottom plane structure of the antenna shell is used to fix the Beidou multi-mode timing active antenna on the plane base metal fixing plate by fastening nuts. The extended part of the metal plate is bent so that a rotation axis fixing hole and a bendable and slidable guide hole are set on the plane of the bent part to ensure that the antenna can be tilted and turned within 90 degrees up and down. Correspondingly, a metal plate that can be fixed to the pole is configured. Two rotation axis fixing holes are set at one end of the plate surface corresponding to the plane base metal fixing plate so that the whole can be fixed after adjusting the azimuth angle. The other end of the metal fixing plate is a bilaterally symmetrical pole structure, which is fastened to the pole with four screws; 8) The above-mentioned multi-mode antenna combination device combines a broadband ceramic dielectric antenna or a single-frequency ceramic dielectric antenna including a planar or spiral structure antenna according to the use environment, and fixes them on the printed circuit board by stacking them up and down or splitting them in a plane to ensure high-quality reception of navigation and timing signals broadcast by navigation satellites; or sets a single-mode single-frequency or single-mode multi-frequency broadband ceramic dielectric antenna, and selects a single-frequency ceramic dielectric antenna according to the Beidou B2a and B3I radio frequency specifications.

2. According to claim 1, the multi-mode baseband demodulation module of the Beidou multi-mode timing receiving device comprises a multi-mode ceramic dielectric power divider, a ceramic dielectric or surface acoustic wave filter, and a baseband demodulation module, which are installed and mounted on a printed circuit board; characterized in that: The input end of the multi-mode ceramic dielectric power divider is connected to the high-frequency carrier signal from the Beidou multi-mode timing active antenna, and the output end is respectively connected to the three frequency points of B1I, B1C, and GLONASS, or the special ceramic dielectric or surface acoustic wave filter belonging to the B2a and B3I frequency points. The output ends of the ceramic dielectric or surface acoustic wave filter are respectively connected to the input end of the baseband demodulation module. The main and standby timing signals are specified by software compilation. The output is a 1PPS second pulse with an error of less than 50ns, which is used for mobile base stations or power network benchmark timing.

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