Multiplexing method and system based on downlink difference channel of digital multi-beam phased-array antenna

Abstract

The invention discloses a multiplexing method and system based on a downlink difference channel of a digital multi-beam phased-array antenna, and the method comprises the steps: carrying out the digital beam forming of a plurality of space targets through a digital multi-beam phased-array antenna, the bandwidth of a beam signal downlink channel of the digital multi-beam phased-array antenna system needs to cover the maximum signal bandwidth of the plurality of space targets; all the downlink difference signals in the downlink signals of the plurality of space targets share one downlink difference channel, namely all the downlink difference signals are transmitted by the same downlink difference channel, so that the downlink difference channel is saved, and the number of beams formed by the digital multi-beam phased-array antenna system is increased through the saved downlink difference channel; wherein the downlink signal comprises a downlink sum-path beam signal and a downlink difference-path beam signal. According to the invention, the downlink signal channel of the digital multi-beam phased-array antenna system can be effectively utilized, and the number of targets which can be tracked in parallel by the digital multi-beam phased-array antenna system is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of digital multi-beam phased array antennas, and in particular to a multiplexing method and system based on downlink difference channels of digital multi-beam phased array antennas. Background Art

[0002] Digital multi-beam phased array antennas can track and control multiple space targets simultaneously due to their multi-beam working mode and technical advantages of full airspace coverage. In recent years, they have received increasing attention in the research of new antennas and have become a hot area in the research of new antennas.

[0003] One of the biggest technical advantages of digital multi-beam phased array antennas is that they can independently form multiple beams and simultaneously track and control multiple targets in space. Therefore, digital multi-beam phased arrays are equivalent to multiple independent antennas. The number of beams that can work in parallel in a digital multi-beam phased array antenna system is an important performance indicator for the design of digital multi-beam phased array antenna systems. In the design of the antenna system, an uplink signal channel and a downlink signal channel are required for each space target, and in order to complete the automatic tracking function of the antenna to the target, a dual-channel self-tracking method is usually used technically. Therefore, when designing a digital multi-beam phased array antenna system, one uplink signal channel and two downlink signal channels (sum downlink beam signal and difference downlink signal) must be designed for each space target. In engineering practice, the uplink and downlink (downlink beam signals include downlink beam sum signals and downlink beam difference signals) digital beam signals of digital multi-beam phased array antenna systems are generally implemented in a tree-structured multi-level digital beam forming (DBF) unit using large-scale digital integrated circuits and transmitted between processing units at each level through digital optical fibers. Since the physical interface of the digital optical fiber channel that can be implemented between digital beam forming units is limited, the number of targets in the digital multi-beam phased array antenna system is limited. Therefore, how to effectively utilize the uplink and downlink signal channels and increase the number of targets that can work in parallel in the digital multi-beam phased array antenna system has become a key technical problem that urgently needs to be broken through. Summary of the invention

[0004] In view of this, the present invention provides a multiplexing method and system based on the downlink difference channel of a digital multi-beam phased array antenna, which can effectively utilize the downlink signal channel of the digital multi-beam phased array antenna system and increase the number of targets that can be tracked in parallel by the digital multi-beam phased array antenna system.

[0005] The present invention discloses a multiplexing method based on a downlink difference channel of a digital multi-beam phased array antenna, which comprises:

[0006] When the digital multi-beam phased array antenna performs digital beamforming for multiple space targets, the bandwidth of the beam signal downlink channel of the digital multi-beam phased array antenna system needs to be able to cover the maximum signal bandwidth of the multiple space targets; all downlink beam difference path signals in the downlink signals of the multiple space targets share a downlink difference channel, that is, the same downlink difference channel transmits all downlink beam difference path signals to save downlink difference channels, and the number of beams formed by the digital multi-beam phased array antenna system is increased through the saved downlink difference channels; wherein the downlink signal includes a downlink beam sum signal and a downlink beam difference signal.

[0007] Furthermore, for the downlink signal of each space target, all downlink beam difference path signals in the downlink signal share a downlink difference channel, including:

[0008] Assuming that the bandwidth of the downlink channel of the beam signal of the digital multi-beam phased array antenna can cover n space targets, for the downlink signals of the n targets, after the downlink beam sum signal and the downlink beam difference signal are formed in the first-level digital beamforming unit, the n downlink beam difference signals are superimposed on the same downlink difference channel according to the difference channel multiplexing method, that is, a multiplexed downlink beam difference signal is formed.

[0009] Furthermore, it also includes:

[0010] The downlink beam sum path signals of n beams and the multiplexed downlink beam difference path signals are sent to the m-th level digital beam forming unit through the downlink sum channel and the downlink difference channel between the digital beam forming units respectively. Finally, the m-th level digital beam forming unit distributes the downlink beam sum path signals of the beams formed by n targets and the multiplexed downlink beam difference path signals in the same downlink difference channel to the back-end information processing unit.

[0011] Furthermore, the multiplexed downlink beam difference path signal in the same downlink difference channel is connected to the back-end information processing unit through the multiplexed difference channel processing unit;

[0012] The multiplexed differential channel processing unit locks the data frame in the multiplexed downlink channel signal through the data frame synchronization unit, and then inputs the frame synchronization signal output by the data frame synchronization unit and the beam number to be decomposed from the multiplexed downlink beam difference path signal into the beam difference signal generation unit to output the downlink beam difference path signal corresponding to the beam number, and outputs it to the digital tracking receiver, and finally the digital tracking receiver demodulates the tracking angle error signal of the beam according to the downlink beam sum path signal of the beam; the back-end information processing unit includes a digital tracking receiver.

[0013] Furthermore, the method of multiplexing the difference channels is used to superimpose n downlink beam difference path signals onto the same downlink difference channel, that is, to form a multiplexed downlink beam difference path signal, including:

[0014] The downlink beam difference path signals of n beams corresponding to n space targets are transmitted through the same downlink difference channel; the number of multiplexed downlink beam difference path signals is N. 差路复用 for:

[0015]

[0016] Among them, S 差通道 is the maximum sampling rate of the downlink differential channel transmission, S 差信号 is the sampling rate of the downlink beam difference signal.

[0017] Furthermore, S 差通道 The corresponding spectrum bandwidth of the downlink difference channel is 2f w The relationship between them is: 差通道 =2·(2f w );S 差信号 The corresponding downlink beam difference signal bandwidth is 2f a The relationship between them is: 差信号 =2·(2f a ).

[0018] Furthermore, the difference channel multiplexing unit in the first-level digital beam forming unit receives the downlink beam difference path signals sent by n beams, and performs digital filtering processing on each difference path signal, compresses the difference path signal bandwidth into the bandwidth of the beam signal downlink channel of the multi-beam phased array antenna system, and then performs downsampling processing on the n downlink beam difference path signals through the downsampling extraction unit, and finally sends the downsampled downlink beam difference path signals of the n beams to the data recombination unit for data recombination, and finally the data recombination unit uses the same difference channel to output the multiplexed downlink beam difference path signal.

[0019] Further, the downsampling process of the n downlink beam difference path signals by the downsampling extraction unit includes:

[0020] The original sampling rate is S 原 The n downlink beam difference path signals are downsampled, and the sampling rate after downsampling is S 降 =S 原 1 / k, that is, extracting data at intervals of k bits from the original sampled data;

[0021] The down-sampling downlink beam difference path signals of the n beams are sent to the data recombination unit for data recombination, including:

[0022] The data recombining unit arranges the received n down-sampled downlink beam difference path signals in sequence, and adds a data frame header in front of the arranged signals to form a difference channel data frame, that is, a multiplexed downlink beam difference path signal;

[0023] Among them, the transmission rate of the difference channel multiplexing unit is S 原 , and the data transmission rate of each downlink beam difference channel signal is equal to the transmission rate of each difference channel data frame, which is S 降 .

[0024] The present invention also discloses a multiplexing system based on a downlink difference channel of a digital multi-beam phased array antenna, which is used to implement any of the multiplexing methods described above based on a downlink difference channel of a digital multi-beam phased array antenna, comprising m-level cascade-connected digital beamforming units, i.e., a first-level digital beamforming unit to an m-th-level digital beamforming unit; a downlink sum channel and a downlink difference channel are formed between the m-level cascade-connected digital beamforming units;

[0025] Each level of digital beam forming unit includes a difference channel multiplexing unit, the difference channel multiplexing unit includes a data compound unit and n branches, the data compound unit is connected to the n branches respectively; each branch includes a digital filter and a downsampling extraction unit connected in sequence; the n branches and the n downlink beam difference channel signals are in a one-to-one correspondence; each downlink beam difference channel signal passes through the digital filter and the downsampling extraction unit in sequence and then enters the data compound unit to form a multiplexed downlink beam difference channel signal.

[0026] Furthermore, it also includes a multiplexed differential channel processing unit connected to the output end of the m-th level digital beam forming unit; the multiplexed differential channel processing unit includes a data frame synchronization unit and a beam difference signal generating unit connected in sequence; the beam difference signal generating unit is connected to the digital tracking receiver.

[0027] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0028] 1. The present invention uses a downsampling extraction method for the difference path signal to make multiple difference path signals share a beam downlink signal channel, thereby saving the antenna downlink signal channel, and then the number of beams formed by the digital multi-beam phased array antenna system can be increased through the downlink signal channel saved by this method. This method can increase the number of beams formed by the digital multi-beam phased array antenna system without increasing system resources, solving a key problem in the design of the digital multi-beam phased array antenna system.

[0029] 2. The present invention is simple to implement, occupies less resources, and reduces the system design cost. The present invention does not require complex circuits, and the implementation method is relatively simple. The present invention only uses the original equipment of the system without adding additional equipment, and only uses software algorithms to realize the function of multiple differential signals sharing one beam downlink signal channel, which is convenient for automatic operation and reduces the system design cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0031] Figure 1 It is a structural schematic diagram of a digital beam processing subsystem of a digital multi-beam phased array antenna system.

[0032] Figure 2 It is a schematic diagram of the spectrum occupancy of the difference signal channel of the downlink beam of the digital multi-beam phased array antenna system.

[0033] Figure 3 It is a schematic diagram of the structure of the first-level digital beam processing unit using differential channel multiplexing technology.

[0034] Figure 4 It is a schematic diagram of the structure of the digital beam processing subsystem using differential channel multiplexing technology.

[0035] Figure 5 It is a schematic diagram of the structure of the channel multiplexing unit in the first-level digital beam processing unit.

[0036] Figure 6 It is a data processing schematic diagram of the downsampling decimation unit of the channel multiplexing unit.

[0037] Figure 7 It is a schematic diagram of data multiplexing processing of the data compound unit of the channel multiplexing unit.

[0038] Figure 8 It is a signal processing flow diagram of angular tracking error signal demodulation of a digital multi-beam phased array antenna system using differential channel technology. DETAILED DESCRIPTION

[0039] The present invention is further described in conjunction with the accompanying drawings and embodiments, and the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present invention.

[0040] See also Figure 1 The present invention provides an embodiment of a multiplexing method for downlink difference channels based on a digital multi-beam phased array antenna, which includes:

[0041] When the digital multi-beam phased array antenna performs digital beamforming for multiple space targets, the bandwidth of the beam signal downlink channel of the digital multi-beam phased array antenna system needs to be able to cover the maximum signal bandwidth of the multiple space targets; all downlink beam difference path signals in the downlink signals of the multiple space targets share a downlink difference channel, that is, the same downlink difference channel transmits all downlink beam difference path signals to save downlink difference channels, and the number of beams formed by the digital multi-beam phased array antenna system is increased through the saved downlink difference channels; wherein the downlink signal includes a downlink beam sum signal and a downlink beam difference signal.

[0042] Specifically, the downlink beam sum signal and the downlink beam difference signal are implemented in a tree-structured multi-stage digital beamforming (DBF) unit using large-scale digital integrated circuits and transmitted between processing units at each level through digital optical fibers. Since the physical interface of the digital optical fiber channel that can be implemented between digital beamforming units is limited, the number of beams that can be implemented by the digital multi-beam phased array antenna system is limited.

[0043] Since the digital multi-beam phased array antenna system needs to consider the digital beam forming for a variety of different space targets during design, the bandwidth of the downlink channel of its beam signal must cover the maximum signal bandwidth of all possible space targets. However, in the angular tracking of the phased array antenna, the bandwidth of its difference path signal is often narrowband. Therefore, these difference path signals can be extracted by taking a method of downsampling the narrowband signal, so that multiple difference path signals share a beam downlink signal channel, thereby saving the antenna downlink signal channel. In addition, the downlink signal channel saved by this method can increase the number of beams formed by the digital multi-beam phased array antenna system and improve the performance of the digital multi-beam phased array antenna system.

[0044] In this embodiment, for the downlink signal of each space target, all downlink beam difference path signals in the downlink signal share a downlink difference channel, including:

[0045] Assuming that the bandwidth of the downlink channel of the beam signal of the digital multi-beam phased array antenna can cover n space targets, for the downlink signals of the n targets, after the downlink beam sum signal and the downlink beam difference signal are formed in the first-level digital beam forming unit, the n downlink beam difference signals are superimposed on the same downlink difference channel according to the difference channel multiplexing method, that is, a multiplexed downlink beam difference signal is formed. n is a positive integer.

[0046] In this embodiment, it also includes:

[0047] The downlink beam sum path signals of n beams and the multiplexed downlink beam difference path signals are sent to the m-th level digital beam forming unit through the downlink sum channel and the downlink difference channel between the digital beam forming units respectively. Finally, the m-th level digital beam forming unit distributes the downlink beam sum path signals of the beams formed by n targets and the multiplexed downlink beam difference path signals in the same downlink difference channel to the back-end information processing unit.

[0048] In this embodiment, the multiplexed downlink beam difference path signal in the same downlink difference channel is connected to the back-end information processing unit through the multiplexed difference channel processing unit;

[0049] The multiplexed differential channel processing unit locks the data frame in the multiplexed downlink channel signal through the data frame synchronization unit, and then inputs the frame synchronization signal output by the data frame synchronization unit and the beam number to be decomposed from the multiplexed downlink beam difference path signal into the beam difference signal generation unit to output the downlink beam difference path signal corresponding to the beam number, and outputs it to the digital tracking receiver, and finally the digital tracking receiver demodulates the tracking angle error signal of the beam according to the downlink beam sum path signal of the beam; the back-end information processing unit includes a digital tracking receiver.

[0050] In this embodiment, the method of multiplexing the difference channels to superimpose n downlink beam difference path signals onto the same downlink difference channel, i.e., to form a multiplexed downlink beam difference path signal, includes:

[0051] The downlink beam difference path signals of n beams corresponding to n space targets are transmitted through the same downlink difference channel; the number of multiplexed downlink beam difference path signals is N. 差路复用 for:

[0052]

[0053] Among them, S 差通道 is the maximum sampling rate of the downlink differential channel transmission, S 差信号 is the sampling rate of the downlink beam difference signal.

[0054] In this embodiment, S 差通道 The corresponding spectrum bandwidth of the downlink difference channel is 2f w The relationship between them is: 差通道 =2·(2f w );S 差信号 The corresponding downlink beam difference signal bandwidth is 2f a The relationship between them is: 差信号 =2·(2f a ).

[0055] In this embodiment, the difference channel multiplexing unit in the first-stage digital beam forming unit receives downlink beam difference path signals sent by n beams, and performs digital filtering processing on each difference path signal, compresses the difference path signal bandwidth into the bandwidth of the beam signal downlink channel of the multi-beam phased array antenna system, and then performs downsampling processing on the n downlink beam difference path signals through the downsampling extraction unit, and finally sends the downsampled downlink beam difference path signals of the n beams to the data recombination unit for data recombination, and finally the data recombination unit uses the same difference channel to output the multiplexed downlink beam difference path signal.

[0056] In this embodiment, the downsampling process of the n downlink beam difference path signals by the downsampling extraction unit includes:

[0057] The original sampling rate is S 原 The n downlink beam difference path signals are downsampled, and the sampling rate after downsampling is S 降 =S 原 1 / k, that is, extracting data at intervals of k bits from the original sampled data;

[0058] The down-sampling downlink beam difference path signals of the n beams are sent to the data recombination unit for data recombination, including:

[0059] The data recombining unit arranges the received n down-sampled downlink beam difference path signals in sequence, and adds a data frame header in front of the arranged signals to form a difference channel data frame, that is, a multiplexed downlink beam difference path signal;

[0060] Among them, the transmission rate of the difference channel multiplexing unit is S 原 , and the data transmission rate of each downlink beam difference channel signal is equal to the transmission rate of each difference channel data frame, which is S 降 .

[0061] The present invention also provides an embodiment of a multiplexing system based on a downlink difference channel of a digital multi-beam phased array antenna, which is used to implement the multiplexing method based on a downlink difference channel of a digital multi-beam phased array antenna described in the above embodiment, comprising m-level cascade-connected digital beamforming units, that is, a first-level digital beamforming unit to an m-th-level digital beamforming unit; a downlink sum channel and a downlink difference channel are formed between the m-level cascade-connected digital beamforming units; m is a positive integer;

[0062] Each level of digital beam forming unit includes a difference channel multiplexing unit, the difference channel multiplexing unit includes a data compound unit and n branches, the data compound unit is connected to the n branches respectively; each branch includes a digital filter and a downsampling extraction unit connected in sequence; the n branches and the n downlink beam difference channel signals are in a one-to-one correspondence; each downlink beam difference channel signal passes through the digital filter and the downsampling extraction unit in sequence and then enters the data compound unit to form a multiplexed downlink beam difference channel signal.

[0063] In this embodiment, it also includes a multiplexed differential channel processing unit connected to the output end of the m-th level digital beam forming unit; the multiplexed differential channel processing unit includes a data frame synchronization unit and a beam difference signal generating unit connected in sequence; the beam difference signal generating unit is connected to the digital tracking receiver.

[0064] For ease of understanding, the present invention provides a more specific embodiment:

[0065] See also Figure 1 and Figure 2 The digital multi-beam phased array antenna system consists of an antenna unit, a digital beamforming subsystem and a backend information processing unit. The digital beamforming subsystem is further divided into multiple levels of digital beamforming units according to the size of the antenna. The first-level digital beamforming unit is connected to the antenna unit, and the n-th-level digital beamforming unit is connected to the backend information processing unit. Figure 1 As shown in the figure, for the downlink signal of the same target, the first-level digital beamforming unit receives the downlink signal sent by the antenna unit and forms a downlink beam according to the downlink beamforming algorithm. The downlink beam contains two downlink signals, the downlink sum channel and the downlink difference channel. At the same time, the downlink sum channel and the downlink difference channel between the digital beamforming units at each level are used for transmission step by step.

[0066] The downlink beam sum signal and the downlink beam difference signal are combined and finally sent to the n-th level digital beam forming unit, and finally the n-th level digital beam forming unit distributes the downlink beam sum signal and the downlink beam difference signal to the back-end information processing unit.

[0067] In order to meet the needs of downlink beamforming for multiple space targets in the digital multi-beam phased array antenna system, the spectrum bandwidth of the downlink sum channel and downlink difference channel between each level of digital beamforming units must be designed to meet the transmission needs of the target's maximum downlink signal bandwidth. For the sum and difference dual-channel tracking adopted by the antenna, since there is no need to demodulate information from the difference channel signal, the spectrum of the difference channel signal can be compressed very narrow. Figure 2 As shown in the figure, the spectrum bandwidth 2f of the downlink difference channel between each level of digital beamforming units in the digital multi-beam phased array antenna system is w, the downlink beam difference signal bandwidth of the space target is 2f a , where 2f w >>2f a For example, in the phased array antenna design, the spectrum bandwidth of the downlink channel is designed to be 2f w =100MHz, and the downlink beam difference signal bandwidth is designed to be 2f a =1MHz.

[0068] See also Figure 3 and Figure 4 .like Figure 3 As shown, a difference channel multiplexing unit is added to the first-level digital beamforming unit, and its function is to transmit the downlink beam difference path signals of each beamformation through the same difference channel. 差路复用 Calculate according to the following algorithm:

[0069]

[0070] Among them, S 差通道 is the maximum sampling rate of the difference channel transmission, and its spectrum bandwidth 2f of the downlink difference channel w The relationship is: S 差通道 =2·(2f w );S 差信号 is the sampling rate of the difference signal, which is proportional to the bandwidth of the difference signal 2f a The relationship is: S 差信号 =2·(2f a ); The reason for subtracting 1 in the calculation of the number of differential path signal multiplexing will be Figure 7 In the description.

[0071] For example, in the phased array antenna design, the spectrum bandwidth of the downlink channel is designed to be 2f w =100MHz, and the downlink beam difference signal bandwidth is designed to be 2f a =1MHz. It can be calculated that: S 差通道 =

[0072] 200MHz, S 差信号 =2MHz; from this we can calculate: That is, according to this method, the same path difference channel can be used for multiplexing 99 downlink beam difference path signals.

[0073] like Figure 4As shown, for the downlink signal of the same target, after the first-level digital beamforming unit forms the downlink beam sum signal and the downlink beam difference signal, the difference signals of multiple beams are superimposed on the same difference channel according to the difference channel multiplexing method. At the same time, by using the downlink sum channel and downlink difference channel between the digital beamforming units at each level, the downlink beam sum signal of each beam and the multiplexed downlink beam difference signal of the same downlink difference channel are sent to the n-level digital beamforming unit step by step, and finally the n-level digital beamforming unit distributes the downlink beam sum signal of each beam and the multiplexed downlink beam difference signal of the same downlink difference channel to the back-end information processing unit for processing.

[0074] See also Figure 5 , Figure 6 and Figure 7 .like Figure 5 As shown, the difference channel multiplexing unit in the first-level digital beamforming unit receives the downlink beam difference path signals sent by each beam, and first performs digital filtering processing on each difference path signal to compress the difference path signal bandwidth into the difference path signal bandwidth designed by the system, and then performs downsampling processing on each difference path signal, that is, the sampling rate of the signal is reduced to the sampling rate corresponding to the signal bandwidth designed for the difference path signal, and finally the downsampled downlink beam difference path signals of each beam are sent to the data recombination unit for data recombination, and finally the data recombination unit sends out the multiplexed downlink beam difference path signals using the same difference channel.

[0075] like Figure 6 As shown, the original sampling rate is S 原 The downlink beam difference signal is downsampled to obtain a sampling rate of S 降 =S 原 ·1 / k processing, that is, extracting data at intervals of k bits from the original sampled data. For example, the original sampled data is:

[0076] {S1, S2, S3, ..., S m , …, S n}

[0077] The extracted data after downsampling the original sampled data by 1 / k is:

[0078] {S1, S k+1 , S 2k+1 , …, S m·k+1 , …, S n}

[0079] For example, the original sampling rate of the system is S 原 =200MHz, the sampling rate after reducing by 1 / 100 is S 降 =S 原 1 / 100 = 2 MHz.

[0080] like Figure 7 As shown, the data multiplexing unit adopts a data frame format, that is, each frame of data is composed of a data frame header plus the data after downsampling of each beam, that is: data frame header + difference channel signal 1_S1 of beam 1 + difference channel signal 2_S2 of beam 2 + ... + difference channel signal n_S1 of beam n + data frame header + difference channel signal 1_S2 of beam 1 + .... The transmission rate of the difference channel multiplexing unit is S 原 , and the data transmission rate of the difference signal of each beam is equal to the transmission rate of each frame of data S 降 Since each frame of data adds a unit of frame header data, the number of multiplexing of the difference channel signal N 差路复用 In the calculation formula, the number of multiplexed difference path signals needs to be reduced by 1. Figure 7 The first frame difference channel data frame and the second frame difference channel data frame respectively correspond to n downlink signals formed by the digital multi-beam phased array antenna system for n space targets at adjacent moments, specifically corresponding to signals after the n downlink signals are downsampled.

[0081] See also Figure 8 , using the difference channel multiplexing technology provided by the present invention, before demodulating the angle error signal, it is necessary to separate the difference signals of each multiplexed beam and send them to each beam tracking receiver for processing. Figure 8 As shown, in the multiplexed differential channel processing unit, the data frame in the multiplexed downlink channel signal is first locked by the data frame synchronization unit, and then the frame synchronization signal and the beam number m to be decoded are used to decode the differential path data corresponding to beam m from the data frame and send it to the digital tracking receiver. Finally, the tracking receiver demodulates the tracking angle error signal of beam m according to the downlink beam sum signal of the beam.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A multiplexing method based on downlink difference channels of digital multi-beam phased array antenna, characterized in that: include: When the digital multi-beam phased array antenna performs digital beamforming for multiple space targets, the bandwidth of the beam signal downlink channel of the digital multi-beam phased array antenna system needs to be able to cover the maximum signal bandwidth of the multiple space targets; all downlink beam difference path signals in the downlink signals of the multiple space targets share a downlink difference channel, that is, the same downlink difference channel transmits all downlink beam difference path signals to save downlink difference channels, and the number of beams formed by the digital multi-beam phased array antenna system is increased through the saved downlink difference channels; wherein the downlink signal includes a downlink beam sum signal and a downlink beam difference signal.

2. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 1, characterized in that: For the downlink signal of each space target, all downlink beam difference path signals in the downlink signal share a downlink difference channel, including: Assuming that the bandwidth of the downlink channel of the beam signal of the digital multi-beam phased array antenna can cover n space targets, for the downlink signals of the n targets, after the downlink beam sum signal and the downlink beam difference signal are formed in the first-level digital beamforming unit, the n downlink beam difference signals are superimposed on the same downlink difference channel according to the difference channel multiplexing method, that is, a multiplexed downlink beam difference signal is formed.

3. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 2, characterized in that: Also includes: The downlink beam sum path signals of n beams and the multiplexed downlink beam difference path signals are sent to the m-th level digital beam forming unit through the downlink sum channel and the downlink difference channel between the digital beam forming units respectively. Finally, the m-th level digital beam forming unit distributes the downlink beam sum path signals of the beams formed by n targets and the multiplexed downlink beam difference path signals in the same downlink difference channel to the back-end information processing unit.

4. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 3 is characterized in that: The multiplexed downlink beam difference path signal in the same downlink difference channel is connected to the back-end information processing unit through the multiplexed difference channel processing unit; The multiplexed differential channel processing unit locks the data frame in the multiplexed downlink channel signal through the data frame synchronization unit, and then inputs the frame synchronization signal output by the data frame synchronization unit and the beam number to be decomposed from the multiplexed downlink beam difference path signal into the beam difference signal generation unit to output the downlink beam difference path signal corresponding to the beam number, and outputs it to the digital tracking receiver, and finally the digital tracking receiver demodulates the tracking angle error signal of the beam according to the downlink beam sum path signal of the beam; the back-end information processing unit includes a digital tracking receiver.

5. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 2, characterized in that: The method of multiplexing the difference channels is used to superimpose n downlink beam difference path signals onto the same downlink difference channel, that is, to form a multiplexed downlink beam difference path signal, including: The downlink beam difference path signals of n beams corresponding to n space targets are transmitted through the same downlink difference channel; the number of multiplexed downlink beam difference path signals is N. 差路复用 for: Among them, S 差通道 is the maximum sampling rate of the downlink differential channel transmission, S 差信号 is the sampling rate of the downlink beam difference signal.

6. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 5, characterized in that: S 差通道 The corresponding spectrum bandwidth of the downlink difference channel is 2f w The relationship between them is: 差通道 =2·(2f w );S 差信号 The corresponding downlink beam difference signal bandwidth is 2f a The relationship between them is: 差信号 =2·(2f a ).

7. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 2, characterized in that: The difference channel multiplexing unit in the first-level digital beamforming unit receives the downlink beam difference path signals sent by n beams, and performs digital filtering processing on each difference path signal, compressing the difference path signal bandwidth into the bandwidth of the beam signal downlink channel of the multi-beam phased array antenna system, and then downsampling the n downlink beam difference path signals through the downsampling extraction unit, and finally sending the downsampled downlink beam difference path signals of the n beams to the data recombination unit for data recombination, and finally the data recombination unit uses the same difference channel to output the multiplexed downlink beam difference path signal.

8. The method for multiplexing downlink difference channels based on digital multi-beam phased array antenna according to claim 7, characterized in that: The downsampling process of the n downlink beam difference path signals by the downsampling extraction unit includes: The original sampling rate is S 原 The n downlink beam difference path signals are downsampled, and the sampling rate after downsampling is S 降 =S 原 1 / k, that is, extracting data at intervals of k bits from the original sampled data; The down-sampling downlink beam difference path signals of the n beams are sent to the data recombination unit for data recombination, including: The data recombining unit arranges the received n down-sampled downlink beam difference path signals in sequence, and adds a data frame header in front of the arranged signals to form a difference channel data frame, that is, a multiplexed downlink beam difference path signal; Among them, the transmission rate of the difference channel multiplexing unit is S 原 , and the data transmission rate of each downlink beam difference channel signal is equal to the transmission rate of each difference channel data frame, which is S 降 .

9. A multiplexing system based on a downlink difference channel of a digital multi-beam phased array antenna, used to implement the multiplexing method based on a downlink difference channel of a digital multi-beam phased array antenna according to any one of claims 1 to 8, characterized in that: It comprises m-level cascade-connected digital beam forming units, namely, a first-level digital beam forming unit to an m-th-level digital beam forming unit; a downlink sum channel and a downlink difference channel are formed between the m-level cascade-connected digital beam forming units; Each level of digital beam forming unit includes a difference channel multiplexing unit, the difference channel multiplexing unit includes a data compound unit and n branches, the data compound unit is connected to the n branches respectively; each branch includes a digital filter and a downsampling extraction unit connected in sequence; the n branches and the n downlink beam difference channel signals are in a one-to-one correspondence; each downlink beam difference channel signal passes through the digital filter and the downsampling extraction unit in sequence and then enters the data compound unit to form a multiplexed downlink beam difference channel signal.

10. The multiplexing system based on downlink difference channel of digital multi-beam phased array antenna according to claim 9, characterized in that: Also included is a multiplexed differential channel processing unit connected to the output end of the m-th level digital beam forming unit; The multiplexed differential channel processing unit comprises a data frame synchronization unit and a beam difference signal generating unit which are connected in sequence; the beam difference signal generating unit is connected to a digital tracking receiver.

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