Multi-antenna wireless data transmission communication device and signal switching method thereof

Abstract

The invention discloses a multi-antenna wireless data transmission communication device and a signal switching method thereof. The multi-antenna wireless data transmission communication device comprises a communication antenna array, a wireless data transmission terminal and a GNSS (Global Navigation Satellite System) receiver, the communication antenna array is arranged at the top of an observation pillar of the CORS station and comprises a plurality of communication antennas which are arranged in a circumferential array at intervals according to a preset angle; the GNSS receiver is used for collecting satellite positioning and navigation data, transmitting the satellite positioning and navigation data to the wireless data transmission terminal through the Ethernet cable, and outputting a 1PPS synchronous signal to the wireless data transmission terminal through the 1PPS coaxial cable; and the wireless data transmission terminal is used for synchronizing a local clock to the 1PPS synchronization signal, and selecting an optimal antenna from each of the two groups of antennas of the communication antenna array according to the signal quality based on the periodically updated antenna switching time slot table for wireless communication. The method is not limited by a preset infrastructure, a wireless ad hoc network system can be conveniently and quickly built, and the CORS station can efficiently access the network.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a multi-antenna wireless data transmission communication device and a signal switching method thereof. Background Art

[0002] With the official launch of the BeiDou-3 global satellite navigation system, domestic GNSS positioning technology has ushered in new development opportunities, and GNSS technology has become increasingly widely used in the surveying and mapping industry. The construction of the CORS (Continuously Operating Reference Stations) system is of great significance as the latest technology and development trend of GPS in China and even the world. In order to ensure the long-term and stable operation of the CORS system, more redundancy considerations are needed in network communications. Wireless ad hoc networks do not rely on preset infrastructure, and have the characteristics of temporary networking, rapid deployment, and strong anti-destruction capabilities. It is undoubtedly a useful supplement to the network access of the CORS system. However, existing ad hoc network equipment generally uses an additional single omnidirectional antenna with low gain, which cannot achieve diversity gain, and cannot be well integrated and conformal with existing CORS station facilities. Summary of the invention

[0003] The present application provides a multi-antenna wireless data communication device and a signal switching method thereof to solve the problem that the existing ad hoc network equipment using an additional single omnidirectional antenna cannot be well integrated and conformal with the existing CORS station facilities.

[0004] According to the first aspect, an embodiment provides a multi-antenna wireless data transmission communication device, the device comprising a communication antenna array, a wireless data transmission terminal and a GNSS receiver;

[0005] The communication antenna array is arranged on the top of the CORS station observation pier, and the communication antenna array includes a plurality of communication antennas arranged in a circular array at preset angle intervals, the plurality of communication antennas are divided into two groups, and two adjacent communication antennas are in different groups;

[0006] The communication antenna array is connected to the wireless data transmission terminal via an antenna feeder, the wireless data transmission terminal is connected to the GNSS receiver via an Ethernet cable and a 1PPS coaxial cable, and the CORS stations realize a self-organizing network function through the wireless data transmission terminal;

[0007] The GNSS receiver is used to collect satellite positioning and navigation data, and transmit it to the wireless data transmission terminal through an Ethernet cable, and output a 1PPS synchronization signal to the wireless data transmission terminal through a 1PPS coaxial cable;

[0008] The wireless data transmission terminal is used to synchronize the local clock to the 1PPS synchronization signal, and based on the periodically updated antenna switching time slot table, select an optimal antenna from each of the two groups of antennas in the communication antenna array according to the signal quality for wireless communication.

[0009] Furthermore, the communication antenna array includes 8 communication antennas, which are arranged in sequence at a circumferential interval of 45°, and can radiate a 360° range around the CORS station observation pier, and a single antenna has a horizontal beam width of 45°.

[0010] Furthermore, eight communication antennas numbered 1-8 are divided into two groups, with even-numbered antennas being divided into one group and odd-numbered antennas being divided into another group.

[0011] Furthermore, the wireless data transmission terminal includes a selector, a radio frequency transceiver and a baseband FPGA, the selector is connected to the radio frequency transceiver, and the radio frequency transceiver is connected to the baseband FPGA via a bus;

[0012] The selector is used to select an optimal antenna from each of the two groups of antennas in the communication antenna array to access the transceiver channel of the radio frequency transceiver;

[0013] The RF transceiver has two independent transceiver channels for accessing two groups of antennas, forming a 2×2 transceiver diversity structure, and adopts a time division duplex mode to up-convert the baseband signal to the RF frequency domain or down-convert the RF signal to the baseband frequency domain;

[0014] The baseband FPGA is used to encode and modulate Ethernet data into baseband signals or decode and demodulate baseband signals into Ethernet data.

[0015] Furthermore, the wireless data transmission terminal also includes a loop filter circuit and a voltage-controlled oscillator connected to the baseband FPGA. The baseband FPGA is also used to receive a 1PPS synchronization signal, generate a pulse modulation signal according to the time difference between the local clock and the 1PPS synchronization signal, and form a voltage-controlled voltage through the loop filter circuit to control the voltage-controlled oscillator so that the output clock approaches the 1PPS synchronization signal, and finally synchronizes with the 1PPS synchronization signal.

[0016] Furthermore, an antenna mounting base is provided on the top of the CORS station observation pier, and the communication antenna array is installed on the antenna mounting base.

[0017] Furthermore, a GNSS antenna is also installed on the antenna mounting base.

[0018] Furthermore, the method for updating the antenna switching time slot table includes:

[0019] Evaluate the received signal power P1-P8 and signal-to-noise ratio S1-S8 of the 8 antennas;

[0020] Calculate the distance D between two wireless data communication devices in the network based on the latitude, longitude and altitude information provided by GNSS xy :

[0021]

[0022] Among them, x and y are the numbers of two current wireless data communication devices, L xy is the horizontal distance, θ is the latitude, is the longitude, H is the altitude;

[0023] Based on the maximum signal-to-noise ratio and the weighted received signal power value as a reference, select the antenna with the best signal quality as the main antenna:

[0024] Smax=max{S(i)},i∈{1,2,3,4,5,6,7,8}

[0025] Cmax=max{Smax+a*P(i)},i∈{1,2,3,4,5,6,7,8}

[0026] S(i) is the antenna receiving signal-to-noise ratio, Smax is the maximum antenna receiving signal-to-noise ratio, P(i) is the antenna receiving level, Cmax is the optimal signal quality evaluation index, the antenna number corresponding to Cmax is m, and the weight a is an empirical value;

[0027] According to the MRC maximum combining principle, an antenna n is selected from another group of antennas as diversity. If m is an odd number, a diversity antenna is selected from the antenna group with an even number. If m is an even number, a diversity antenna is selected from the antenna group with an odd number. The best received signal Zmax with the optimal signal-to-noise ratio after combining is calculated:

[0028] Z={SI*|h m | 2 +SI*|h i | 2}, if m is an odd number, i∈{2,4,6,8}, if m is an even number, i

[0029] ∈{1,3,5,7}

[0030] Z_SNRmax(m)=max{Z_SNR(i)}, if m is an odd number, i∈{2,4,6,8}, if m is an even number, i

[0031] ∈{1,3,5,7}

[0032] Among them, Z is the combined received signal, Z_SNR is the signal-to-noise ratio of the combined signal, Z_SNRmax is the optimal signal-to-noise ratio after screening, and the auxiliary diversity antenna number corresponding to Z_SNRmax is n, hi is the channel gain of the signal received by antenna i, and h is obtained by channel estimation. i , SI is the actual transmitted signal;

[0033] The signal Zmax with the best signal-to-noise ratio after merging is selected as the best receiving signal, and the selected best receiving main antenna number and radial antenna number are (m, n);

[0034] Record the destination device ID and relative distance D xy , diversity antenna numbers m and n, diversity weighting factor |h m | 2 and |h i | 2 , the best combined signal-to-noise ratio Z_SNRmax, and update it to the antenna switching time slot table;

[0035] All wireless data transmission devices in the entire network update their antenna switching time slot tables at regular intervals and broadcast their antenna switching time slot tables to other devices in the entire network. Whenever a new device joins the network, the antenna switching time slot table is updated again.

[0036] According to the second aspect, an embodiment provides a signal switching method for a multi-antenna wireless data communication device, the method comprising:

[0037] The satellite positioning and navigation data is collected through the GNSS receiver and transmitted to the wireless data transmission terminal through the Ethernet cable. At the same time, the 1PPS synchronization signal is output to the wireless data transmission terminal through the 1PPS coaxial cable;

[0038] The local clock is synchronized to the 1PPS synchronization signal through the wireless data transmission terminal, and based on the periodically updated antenna switching time slot table, an optimal antenna is selected from each of the two groups of antennas in the communication antenna array according to the signal quality for wireless communication.

[0039] Furthermore, the method further comprises:

[0040] A selector selects an optimal antenna from each of the two groups of antennas in the communication antenna array to connect to the transceiver channel of the radio frequency transceiver;

[0041] The two independent transmit and receive channels of the RF transceiver are used to access the two antennas, forming a 2*2 transmit and receive diversity structure. The time division duplex mode is used to up-convert the baseband signal to the RF frequency domain or down-convert the RF signal to the baseband frequency domain.

[0042] The baseband FPGA is used to encode and modulate Ethernet data into baseband signals or decode and demodulate baseband signals into Ethernet data, and receive 1PPS synchronization signals. A pulse modulation signal is generated according to the time difference between the local clock and the 1PPS synchronization signal, and a voltage-controlled voltage is formed through a loop filter circuit to control a voltage-controlled oscillator so that the output clock approaches the 1PPS synchronization signal and is finally synchronized with the 1PPS synchronization signal.

[0043] The present application provides a multi-antenna wireless data transmission communication device and a signal switching method thereof, which have the following beneficial effects:

[0044] (1) The multi-antenna wireless data communication device proposed in this application is not restricted by the preset infrastructure, and can easily and quickly build a wireless ad hoc network system to enable CORS stations to efficiently access the network.

[0045] (2) In the present application, the antenna array is designed to be conformal to the observation pier, and 8 antennas are used to achieve 360-degree coverage around the observation pier, which can flexibly realize diversity gain of wireless communication transmission and reception.

[0046] (3) The antenna switching time slot table algorithm in this application forms an antenna switching time slot table based on the signal quality and location topology of all devices in the network, accurately synchronizes the communications of all wireless data transmission terminals in the entire network, and realizes efficient and reliable wireless communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A structural diagram of a multi-antenna wireless data communication device provided by one embodiment of the present invention;

[0048] Figure 2 A diagram showing the composition of an antenna array in a multi-antenna wireless data communication device provided by one embodiment of the present invention;

[0049] Figure 3 A block diagram of antenna array switching principle in a multi-antenna wireless data communication device provided by one embodiment of the present invention;

[0050] Figure 4 A parameter table updating process in a multi-antenna wireless data communication device provided by an embodiment of the present invention;

[0051] Figure 5 A CORS station distribution diagram in a multi-antenna wireless data communication device provided by an embodiment of the present invention.

[0052] In the figure: CORS station observation pier 1, communication antenna array 2, antenna feeder 3, wireless data transmission terminal 4, GNSS receiver 5, Ethernet cable 6, 1PPS coaxial cable 7, GNSS antenna 8, antenna mounting base 9, RF transceiver 10, baseband FPGA 11, loop filter circuit 12, voltage-controlled oscillator 13, selector 14. DETAILED DESCRIPTION

[0053] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0054] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0055] The first embodiment of the present invention provides a multi-antenna wireless data transmission communication device, which can freely select from 8 antenna channels according to signal quality to communicate with one or more wireless data transmission devices, and can realize a CORS wireless ad hoc network system without changing the existing structure of the CORS station. Figure 1 As shown, the device specifically includes a communication antenna array 2, a wireless data transmission terminal 4 and a GNSS receiver 5.

[0056] The communication antenna array 2 is arranged on the top of the CORS station observation pier 1. The communication antenna array 2 includes a plurality of communication antennas arranged in a circular array at preset angle intervals. The plurality of communication antennas are divided into two groups, and two adjacent communication antennas are in different groups.

[0057] In this embodiment, Figure 2As shown, the communication antenna array 2 includes 8 communication antennas, which are arranged in sequence at a circumferential interval of 45°, and can radiate a 360° range around the CORS station observation pier 1, and the horizontal beam width of a single antenna is 45°. The 8 communication antennas numbered 1-8 are divided into two groups, among which the even-numbered (2, 4, 6, 8) are divided into one group, and the odd-numbered (1, 3, 5, 7) are divided into another group.

[0058] In this embodiment, an antenna mounting seat 9 is provided on the top of the CORS station observation pier 1, and the communication antenna array 2 is mounted on the antenna mounting seat 9. A GNSS antenna 8 is also mounted on the antenna mounting seat 9.

[0059] The communication antenna array 2 is connected to the wireless data transmission terminal 4 through the antenna feeder 3, and the wireless data transmission terminal 4 is connected to the GNSS receiver 5 through the Ethernet cable and the 1PPS coaxial cable. The CORS stations realize the self-organizing network function through the wireless data transmission terminal 4.

[0060] The GNSS receiver 5 is used to collect satellite positioning and navigation data, and transmit it to the wireless data transmission terminal 4 through the Ethernet cable 6 , and output the 1PPS synchronization signal to the wireless data transmission terminal 4 through the 1PPS coaxial cable 7 .

[0061] The wireless data transmission terminal 4 is used to synchronize the local clock to the 1PPS synchronization signal, and based on the periodically updated antenna switching time slot table, select an optimal antenna from each of the two groups of antennas in the communication antenna array 2 according to the signal quality for wireless communication.

[0062] In this embodiment, Figure 3 As shown, the wireless data transmission terminal 4 specifically includes a RF transceiver 10, a baseband FPGA 11, a loop filter circuit 12, a voltage-controlled oscillator 13 and a selector 14. The selector 14 is connected to the RF transceiver 10, and the RF transceiver 10 is connected to the baseband FPGA 11 via a bus.

[0063] The selector 14 is used to select an optimal antenna from each of the two antenna groups of the communication antenna array 2 to access the transceiver channel of the RF transceiver 10. Figure 3 As shown, six selectors 14 are used to select two of the eight antennas to access the radio frequency transceiver 10 .

[0064] The RF transceiver 10 has two independent transmit and receive channels for accessing two groups of antennas, forming a 2*2 transmit and receive diversity structure, and adopts a time division duplex mode to up-convert the baseband signal to the RF frequency domain or down-convert the RF signal to the baseband frequency domain.

[0065] The baseband FPGA 11 is used to encode and modulate Ethernet data into baseband signals or decode and demodulate baseband signals into Ethernet data. The baseband FPGA 11 is also used to receive 1PPS synchronization signals, generate pulse modulation signals according to the time difference between the local clock and the 1PPS synchronization signal, and form a voltage-controlled voltage through the loop filter circuit 12 to control the voltage-controlled oscillator 13 so that the output clock approaches the 1PPS synchronization signal, and finally synchronizes with the 1PPS synchronization signal. At the same time, Figure 4 As shown, by periodically performing spectrum detection, the time slot table and the receive diversity weighted table are selected according to the signal quality antenna, and the communication time slot allocation is updated.

[0066] The specific working principle is as follows:

[0067] First, the RF transceiver 10 includes two receiving and transmitting channels, and the antenna array consists of 8 antennas arranged in sequence at a circular interval of 45 degrees. Among them, a group of 1, 3, 5, and 7 chooses one way to access the first channel of the RF transceiver 10, and another group of 2, 4, 6, and 8 chooses one way to access the second channel of the RF transceiver 10. The antenna array covers 360 degrees and is fixed on the top of the observation pier.

[0068] The baseband FPGA 11 generates a pulse modulation signal according to the time difference between the local clock and 1PPS. After loop filtering, the voltage-controlled voltage controls the voltage-controlled oscillator 13 to make the output clock close to the 1PPS synchronization signal and finally synchronize with the 1PPS signal. The clocks of all devices in the entire network are synchronized to the 1PPS signal, thereby ensuring the accurate synchronization of time slot switching.

[0069] The wireless data transmission terminal 4 adopts the time division duplex mode, and the RF transceiver 10 has two independent transceiver channels. Through 6 selectors 14, one antenna is selected from each of the two groups of antennas in the antenna array to connect to the transceiver channel of the RF transceiver 10, which can form a 2×2 transceiver diversity structure. According to the antenna switching time slot table, when communicating with other terminals, the two antennas with the best signal quality can always be selected for communication.

[0070] The method for updating the antenna switching time slot table includes:

[0071] a. Evaluate the received signal power P1-P8 and signal-to-noise ratio S1-S8 of the eight antennas;

[0072] b. Calculate the distance D between two wireless data communication devices in the network based on the latitude, longitude and altitude information provided by GNSS. xy (approximation):

[0073]

[0074]

[0075] Among them, x and y are the numbers of two current wireless data communication devices, L xy is the horizontal distance, θ is the latitude, is the longitude, H is the altitude;

[0076] c. Based on the maximum signal-to-noise ratio and the weighted received signal power value as a reference, select the antenna with the best signal quality as the main antenna:

[0077] Smax=max{S(i)},i∈{1,2,3,4,5,6,7,8}

[0078] Cmax=max{Smax+a*P(i)},i∈{1,2,3,4,5,6,7,8}

[0079] S(i) is the antenna receiving signal-to-noise ratio, Smax is the maximum antenna receiving signal-to-noise ratio, P(i) is the antenna receiving level, Cmax is the optimal signal quality evaluation index, the antenna number corresponding to Cmax is m, and the weight a is an empirical value;

[0080] d. According to the MRC maximum combining principle, select an antenna n from another group of antennas as diversity. If m is an odd number, select the diversity antenna from the antenna group with an even number. If m is an even number, select the diversity antenna from the antenna group with an odd number. Calculate the best received signal Zmax with the optimal signal-to-noise ratio after combining:

[0081] Z={SI*|h m | 2 +SI*|h i | 2}, if m is an odd number, i∈{2,4,6,8}, if m is an even number, i

[0082] ∈{1,3,5,7}

[0083] Z_SNRmax(m)=max{Z_SNR(i)}, if m is an odd number, i∈{2,4,6,8}, if m is an even number, i

[0084] ∈{1,3,5,7}

[0085] Among them, Z is the combined received signal (communication digital signal), Z_SNR is the signal-to-noise ratio of the combined signal, Z_SNRmax is the optimal signal-to-noise ratio after screening, and the auxiliary diversity antenna number corresponding to Z_SNRmax is n, h i is the channel gain of the signal received by antenna i, and h is obtained by channel estimation. i , SI is the actual transmitted signal (communication digital signal);

[0086] e. The signal Zmax with the best signal-to-noise ratio after merging is selected as the best receiving signal. The sequence number of the selected best receiving main antenna and the sequence number of the radial antenna are (m, n);

[0087] f. Record the target device ID and relative distance D xy , diversity antenna numbers m and n, diversity weighting factor |h m | 2 and |h i | 2 , the best combined signal-to-noise ratio Z_SNRmax, and update it to the antenna switching time slot table;

[0088] g. All wireless data transmission devices in the entire network update their antenna switching time slot table at regular intervals and broadcast their antenna switching time slot table to other devices in the entire network. Whenever a new device joins the network, the antenna switching time slot table is updated again.

[0089] Figure 5 The figure is a topological diagram of CORS station distribution. CORS stations realize networking function through wireless data transmission terminal 4. CORS stations can directly communicate with base stations or reach them through other CORS stations. CORS stations receive satellite positioning and navigation data collected by GNSS receiver 5 through wireless data transmission terminal 4, and send satellite data to data transmission base station through wireless communication, and finally send them to CORS server for users to use.

[0090] Corresponding to the above-disclosed multi-antenna wireless data transmission communication device, an embodiment of the present invention further discloses a signal switching method of the multi-antenna wireless data transmission communication device, which specifically includes:

[0091] The satellite positioning and navigation data is collected through the GNSS receiver 5 and transmitted to the wireless data transmission terminal 4 through the Ethernet cable 6, and the 1PPS synchronization signal is output to the wireless data transmission terminal 4 through the 1PPS coaxial cable 7;

[0092] The local clock is synchronized to the 1PPS synchronization signal through the wireless data transmission terminal 4, and based on the periodically updated antenna switching time slot table, an optimal antenna is selected from each of the two groups of antennas in the communication antenna array 2 according to the signal quality for wireless communication.

[0093] Furthermore, the method further comprises:

[0094] The selector 14 selects an optimal antenna from each of the two groups of antennas in the communication antenna array 2 to connect to the transceiver channel of the radio frequency transceiver 10;

[0095] The two independent transceiver channels of the RF transceiver 10 are used to access the two antennas, forming a 2*2 transceiver diversity structure, and adopting a time division duplex mode to up-convert the baseband signal to the RF frequency domain or down-convert the RF signal to the baseband frequency domain;

[0096] The baseband FPGA 11 encodes and modulates the Ethernet data into a baseband signal or decodes and demodulates the baseband signal into Ethernet data, and receives a 1PPS synchronization signal. A pulse modulation signal is generated according to the time difference between the local clock and the 1PPS synchronization signal, and a voltage-controlled voltage is formed through a loop filter circuit 12 to control a voltage-controlled oscillator 13 so that the output clock approaches the 1PPS synchronization signal and is finally synchronized with the 1PPS synchronization signal.

[0097] It should be noted that for a detailed description of a signal switching method for a multi-antenna wireless data communication device provided in an embodiment of the present invention, reference can be made to the relevant description of a multi-antenna wireless data communication device provided in an embodiment of the present application, which will not be repeated here.

[0098] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0099] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A multi-antenna wireless data communication device, characterized in that: The device includes a communication antenna array, a wireless data transmission terminal and a GNSS receiver; The communication antenna array is arranged on the top of the CORS station observation pier, and the communication antenna array includes a plurality of communication antennas arranged in a circular array at preset angle intervals, the plurality of communication antennas are divided into two groups, and two adjacent communication antennas are in different groups; The communication antenna array is connected to the wireless data transmission terminal via an antenna feeder, the wireless data transmission terminal is connected to the GNSS receiver via an Ethernet cable and a 1PPS coaxial cable, and the CORS stations realize a self-organizing network function through the wireless data transmission terminal; The GNSS receiver is used to collect satellite positioning and navigation data, and transmit it to the wireless data transmission terminal through an Ethernet cable, and output a 1PPS synchronization signal to the wireless data transmission terminal through a 1PPS coaxial cable; The wireless data transmission terminal is used to synchronize the local clock to the 1PPS synchronization signal, and based on the periodically updated antenna switching time slot table, select an optimal antenna from each of the two groups of antennas in the communication antenna array according to the signal quality for wireless communication.

2. A multi-antenna wireless data communication device as claimed in claim 1, characterized in that: The communication antenna array includes 8 communication antennas, which are arranged in sequence at a circumferential interval of 45°, and can radiate a 360° range around the CORS station observation pier. The horizontal beam width of a single antenna is 45°.

3. A multi-antenna wireless data communication device as claimed in claim 2, characterized in that: The eight communication antennas numbered 1-8 are divided into two groups, with the even-numbered antennas being divided into one group and the odd-numbered antennas being divided into another group.

4. A multi-antenna wireless data communication device as claimed in claim 1, characterized in that: The wireless data transmission terminal includes a selector, a radio frequency transceiver and a baseband FPGA, wherein the selector is connected to the radio frequency transceiver, and the radio frequency transceiver is connected to the baseband FPGA via a bus; The selector is used to select an optimal antenna from each of the two groups of antennas in the communication antenna array to access the transceiver channel of the radio frequency transceiver; The RF transceiver has two independent transceiver channels for accessing two groups of antennas, forming a 2×2 transceiver diversity structure, and adopts a time division duplex mode to up-convert the baseband signal to the RF frequency domain or down-convert the RF signal to the baseband frequency domain; The baseband FPGA is used to encode and modulate Ethernet data into baseband signals or decode and demodulate baseband signals into Ethernet data.

5. A multi-antenna wireless data communication device as claimed in claim 4, characterized in that: The wireless data transmission terminal also includes a loop filter circuit and a voltage-controlled oscillator connected to the baseband FPGA. The baseband FPGA is also used to receive a 1PPS synchronization signal, generate a pulse modulation signal according to the time difference between the local clock and the 1PPS synchronization signal, and form a voltage-controlled voltage through the loop filter circuit to control the voltage-controlled oscillator so that the output clock approaches the 1PPS synchronization signal, and finally synchronizes with the 1PPS synchronization signal.

6. The multi-antenna wireless data communication device according to claim 1, characterized in that: An antenna mounting base is provided on the top of the CORS station observation pier, and the communication antenna array is installed on the antenna mounting base.

7. A multi-antenna wireless data communication device as claimed in claim 6, characterized in that: A GNSS antenna is also installed on the antenna mounting base.

8. The multi-antenna wireless data communication device according to claim 3, characterized in that: The method for updating the antenna switching time slot table includes: Evaluate the received signal power P1-P8 and signal-to-noise ratio S1-S8 of the 8 antennas; Calculate the distance D between two wireless data communication devices in the network based on the latitude, longitude and altitude information provided by GNSS xy : Among them, x and y are the numbers of two current wireless data communication devices, L xy is the horizontal distance, θ is the latitude, is the longitude, H is the altitude; Based on the maximum signal-to-noise ratio and the weighted received signal power value as a reference, select the antenna with the best signal quality as the main antenna: Smax=max{S(i)}, i∈{1, 2, 3, 4, 5, 6, 7, 8} Cmax=max{Smax+a*P(i)}, i∈{1, 2, 3, 4, 5, 6, 7, 8} S(i) is the antenna receiving signal-to-noise ratio, Smax is the maximum antenna receiving signal-to-noise ratio, P(i) is the antenna receiving level, Cmax is the optimal signal quality evaluation index, the antenna number corresponding to Cmax is m, and the weight a is an empirical value; According to the MRC maximum combining principle, an antenna n is selected from another group of antennas as diversity. If m is an odd number, a diversity antenna is selected from the antenna group with an even number. If m is an even number, a diversity antenna is selected from the antenna group with an odd number. The best received signal Zmax with the optimal signal-to-noise ratio after combining is calculated: Z={SI*|h m | 2 +SI*|h i | 2 }, if m is an odd number, i∈{2, 4, 6, 8}, if m is an even number, i∈{1, 3, 5, 7} Z_SNRmax(m)=max{Z_SNR(i)}, if m is odd, i∈{2,4,6,8}, if m is even, i∈{1,3,5,7} Among them, Z is the combined received signal, Z_SNR is the signal-to-noise ratio of the combined signal, Z_SNRmax is the optimal signal-to-noise ratio after screening, and the auxiliary diversity antenna number corresponding to Z_SNRmax is n, h i is the channel gain of the signal received by antenna i, and h is obtained by channel estimation. i , SI is the actual transmitted signal; The signal Zmax with the best signal-to-noise ratio after merging is selected as the best receiving signal, and the selected best receiving main antenna number and radial antenna number are (m, n); Record the destination device ID and relative distance D xy , diversity antenna numbers m and n, diversity weighting factor |h m | 2 and |h i | 2 , the best combined signal-to-noise ratio Z_SNRmax, and update it to the antenna switching time slot table; All wireless data transmission devices in the entire network update their antenna switching time slot tables at regular intervals and broadcast their antenna switching time slot tables to other devices in the entire network. Whenever a new device joins the network, the antenna switching time slot table is updated again.

9. A signal switching method for a multi-antenna wireless data communication device according to any one of claims 1 to 8, characterized in that: The method comprises: The satellite positioning and navigation data is collected through the GNSS receiver and transmitted to the wireless data transmission terminal through the Ethernet cable. At the same time, the 1PPS synchronization signal is output to the wireless data transmission terminal through the 1PPS coaxial cable; The local clock is synchronized to the 1PPS synchronization signal through the wireless data transmission terminal, and based on the periodically updated antenna switching time slot table, an optimal antenna is selected from each of the two groups of antennas in the communication antenna array according to the signal quality for wireless communication.

10. The signal switching method of a multi-antenna wireless data communication device according to claim 9, characterized in that: The method further comprises: A selector selects an optimal antenna from each of the two groups of antennas in the communication antenna array to connect to the transceiver channel of the radio frequency transceiver; The two independent transmit and receive channels of the RF transceiver are used to access the two antennas, forming a 2*2 transmit and receive diversity structure. The time division duplex mode is used to up-convert the baseband signal to the RF frequency domain or down-convert the RF signal to the baseband frequency domain. The baseband FPGA is used to encode and modulate Ethernet data into baseband signals or decode and demodulate baseband signals into Ethernet data, and receive 1PPS synchronization signals. A pulse modulation signal is generated according to the time difference between the local clock and the 1PPS synchronization signal, and a voltage-controlled voltage is formed through a loop filter circuit to control a voltage-controlled oscillator so that the output clock approaches the 1PPS synchronization signal and is finally synchronized with the 1PPS synchronization signal.

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