A fully polarized SAR radio frequency network

Abstract

The present invention provides a fully polarized SAR radio frequency network, including a signal processing radio frequency network 1 and a signal processing radio frequency network 2, wherein the signal processing radio frequency network 2 includes an antenna and a power division network, a calibration network and a plurality of TR components distributed therein, wherein the power division network and the calibration network both communicate bidirectionally with the signal processing radio frequency network 1, and each interface of the power division network and the calibration network corresponds to the same TR component, and each TR component is connected to the polarization port of the antenna. Beneficial effects of the present invention: the present invention can significantly reduce the cost, and the total cost is expected to be reduced by 30%; the present invention can greatly shorten the cycle, and the development cycle is expected to be shortened by 20%; the present invention can significantly reduce the weight, and the overall weight of the load is expected to be reduced by 20%.

Description

Technical Field

[0001] The present invention belongs to the technical field of SAR radio frequency networks, and in particular relates to a fully polarized SAR radio frequency network. Background Art

[0002] Since SAR satellites have the ability to penetrate clouds and fog for imaging and detection, and have all-day and all-weather observation capabilities, they have become an important means of earth observation and have been widely valued by various countries. At present, spaceborne SAR has shown broad application value and great potential in the fields of target monitoring, target search, tracking, guidance, mapping, disaster monitoring, resource investigation and marine research.

[0003] Fully polarized SAR can simultaneously record reflected signals of multiple polarization states from ground targets. Compared with traditional single-polarized or partially polarized SAR, fully polarized SAR can provide richer information, which is very useful for applications such as ground object classification, change detection, and disaster assessment. Currently, commercial SAR payloads are still dominated by single polarization. The main reasons are:

[0004] The fully polarized SAR payload has the characteristics of large size, heavy weight, high cost and long development cycle due to its complex system. It is precisely because of these characteristics of fully polarized SAR that it is difficult for commercial aerospace companies to launch fully polarized SAR payloads, which to some extent restricts the development of fully polarized SAR.

[0005] Traditional fully polarized SAR RF architecture Figure 1 As shown. Both linear polarizations have a set of independent channels. This method has high reliability, but it is costly, heavy, and has a long cycle. Summary of the invention

[0006] In view of this, the present invention aims to provide a fully polarized SAR radio frequency network to solve at least one problem existing in the above-mentioned prior art.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A fully polarized SAR radio frequency network comprises a signal processing radio frequency network 1 and a signal processing radio frequency network 2, wherein the signal processing radio frequency network 2 comprises an antenna and a power division network, a calibration network and a plurality of TR components distributed therein, wherein the power division network and the calibration network both communicate bidirectionally with the signal processing radio frequency network 1, each interface of the power division network and the calibration network respectively corresponds to the same TR component, and each TR component is respectively connected to a polarization port of the antenna;

[0009] The working mode of the radio frequency network includes imaging / calibration tasks and polarization working modes, wherein the imaging / calibration tasks include imaging tasks, reference calibration tasks, transmission calibration tasks and reception calibration tasks; the polarization working modes include single polarization polarization switching modes, dual polarization polarization switching modes and full polarization polarization switching modes;

[0010] The signal processing radio frequency network 1 includes a transmitter, a driving power amplifier, a radar coupler, a power amplifier, a radar circulator, a limiter, three switch arrays and a receiver. The transmitter is connected to port 1 of the radar coupler through the driving power amplifier, port 3 of the radar coupler is connected to a switch array, the switch array is respectively connected to the receiver and the fixed attenuator through two switch arrays, port 2 of the radar coupler is connected to port 1 of the radar circulator through the power amplifier, the power division network is connected to port 2 of the radar circulator, and port 3 of the radar circulator is connected to the receiver through the limiter and a switch array.

[0011] Furthermore, each of the TR components includes two TR switches, a transmitting branch, a receiving branch, a TR coupler and switch one. The transmitting branch and the receiving branch are connected between the two TR switches. One TR switch is connected to the power division network, and the other TR switch is connected to the antenna through the TR coupler and switch one in sequence. The TR coupler is also connected to the calibration network.

[0012] Furthermore, the signal path of the imaging task includes:

[0013] During the transmission of the imaging mission signal, the transmission signal is sent from the transmitter, and after driving the power amplifier, the radar coupler, and the power amplifier, it reaches the port 1 of the radar circulator, and is output from the port 2 of the radar circulator to the power division network, and then output from the power division network to the transmission branch of each TR component, and finally output to the antenna through the switch 1 selection;

[0014] During the reception of imaging mission signals, the echo signal is polarized through switch 1, and the selection signal is output to the power division network through the receiving branches of each TR component, and then output to the receiver through the radar circulator, limiter and switch matrix to complete the signal reception.

[0015] Furthermore, the signal path of the reference calibration task includes:

[0016] For the reference calibration task, the calibration signal is sent from the transmitter, output to two switch matrices through the radar coupler port 3, and then output to the receiver after selection by the switch matrix to complete the reference calibration signal reception.

[0017] Furthermore, the signal path of the emission calibration task includes:

[0018] During the transmission calibration task, the transmission signal is sent out from the transmitter, passes through the driver amplifier, radar coupler, and power amplifier, and then enters the radar circulator. It is then output to the power division network and TR component through the radar circulator. The transmission calibration signal passes through the transmission branch of the TR component and is output to the calibration network through the TR coupler. It is then selected through the fixed attenuator and switch matrix and output to the receiver.

[0019] Further, the signal path for receiving the calibration task includes:

[0020] During the receiving calibration task, the calibration signal is sent out from the transmitter, passes through the driver amplifier, the three ports of the radar coupler, the switch matrix, and the fixed attenuator, and then is output to the calibration network. Then, it passes through each TR coupler and the receiving branch and is output to the power division network for combining. After passing through the radar circulator and limiter, it is selected by the switch matrix to be received by the receiver, thus completing the reception of the calibration signal.

[0021] Furthermore, the single polarization polarization switching method includes:

[0022] When single polarization is used, if V polarization is selected, switch 1 selects V polarization in both the transmitting state and the receiving state, and the settings of the remaining switches are selected according to the imaging / calibration task.

[0023] Furthermore, the dual-polarization switching method includes:

[0024] When dual polarization is used, if VV / HH polarization is selected, each PRT of switch 1 switches polarization in turn, the current PRT selects V polarization, and the next PRT selects H polarization; the polarization of the transmit and receive state switch 1 in each PRT is not switched.

[0025] Furthermore, the full polarization switching method includes:

[0026] When full polarization is used, if VV / VH / HH / HV polarization is selected, then in the transmitting stage of the first PRT, switch 1 is set to V polarization; in the receiving stage of the first PRT, switch 1 is set to V polarization; in the transmitting stage of the second PRT, switch 1 is set to V polarization; in the receiving stage of the second PRT, switch 1 is set to H polarization; in the transmitting stage of the third PRT, switch 1 is set to H polarization; in the receiving stage of the third PRT, switch 1 is set to H polarization; in the transmitting stage of the fourth PRT, switch 1 is set to H polarization, and in the receiving stage of the fourth PRT, switch 1 is set to V polarization; the subsequent polarization switching is repeated in the above manner.

[0027] Compared with the prior art, the fully polarized SAR radio frequency network described in the present invention has the following advantages:

[0028] The fully polarized SAR radio frequency network described in the present invention can significantly reduce the cost, and the total cost is expected to be reduced by 30%; the present invention can greatly shorten the cycle, and the development cycle is expected to be shortened by 20%; the present invention can significantly reduce the weight, and the overall load weight is expected to be reduced by 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 A schematic diagram of the architecture of a conventional fully polarized SAR system according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of a fully polarized SAR radio frequency network according to an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the signal flow of the transmitting branch according to an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of a receiving branch signal flow according to an embodiment of the present invention;

[0034] Figure 5 A schematic diagram of the reference calibration signal flow according to an embodiment of the present invention;

[0035] Figure 6 A schematic diagram of the flow of a transmission calibration signal according to an embodiment of the present invention;

[0036] Figure 7 A schematic diagram of the flow of a received calibration signal according to an embodiment of the present invention;

[0037] Figure 8 A schematic diagram of a single-polarization polarization switching method according to an embodiment of the present invention;

[0038] Fig. 9 A schematic diagram of a dual-polarization polarization switching method according to an embodiment of the present invention;

[0039] Fig.10 It is a schematic diagram of the full polarization polarization switching mode described in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0043] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0044] like Figure 2 As shown, a fully polarized SAR RF network has the number of transmitting channels and receiving channels cut in half, and is composed of only one set of transmitting and receiving networks, which realizes dual polarization and full polarization through time-division multiplexing.

[0045] Imaging tasks

[0046] During the imaging task signal transmission, the transmission signal flows as follows Figure 3 As shown by the dotted line, the transmission signal is sent from the transmitter, through the driver amplifier, the coupler, the power amplifier, to the port 1 of the radar circulator, and then output from the port 2 of the radar circulator to the power division network, output to the transmission branch of each TR component, and finally output to the antenna through the switch selection.

[0047] During the imaging task signal reception, the echo signal flows as follows Figure 4 As shown by the dotted line, polarization selection is performed through switch 1, and the selected signal is output to the power division network through the receiving branch of each TR component, and then output to the receiver through the radar circulator, limiter and switch matrix to complete the signal reception.

[0048] Reference calibration tasks

[0049] Refer to the calibration task, the calibration signal flow is as follows Figure 5 As shown by the dotted line, the calibration signal is sent out from the transmitter, output to the microwave switch through the coupler 3 port, and then output to the receiving channels after being selected by the microwave switch, thus completing the reception of the reference calibration signal.

[0050] Launch calibration mission

[0051] Transmit calibration task, the calibration signal flows as follows Figure 6 As shown by the dotted line, the transmission signal is sent out from the transmitter, passes through the driver amplifier, the coupler, the power amplifier, and the radar circulator to be output to the power division network. The transmission calibration signal passes through the transmission channels of each TR component inside the antenna, is output to the calibration network through the coupler, is selected by the microwave switch, is output to the three receiving channels, and is finally received by the receiver.

[0052] Receive calibration tasks

[0053] Receive calibration tasks, calibration signal flows as follows Figure 7 As shown by the dotted line, the calibration signal is sent out from the transmitter, driven and amplified, and output to the calibration network at port 3 of the coupler. After passing through each TR component coupler and each receiving branch, it is output to the power division network for combining, passes through the radar circulator and limiter, and is received by the receiver after being selected by the switch, thus completing the reception of the calibration signal.

[0054] The following is a brief description of the RF network switch settings for different polarization working modes.

[0055] Single polarization use

[0056] When single polarization is used, V polarization is taken as an example. Figure 2 The switch 1 in the middle selects V polarization in both the transmitting and receiving states, and the settings of the other microwave switches are switched according to the above tasks. Figure 8 shown.

[0057] Dual polarization use

[0058] When dual polarization is used, VV / HH is used as an example. Figure 2 Each PRT in the middle switch 1 switches polarization in turn. The current PRT selects V polarization, and the next PRT selects H polarization. The polarization of the transmit and receive state switch 1 in each PRT does not switch. The polarization switching diagram is shown in Fig. 9 shown.

[0059] Full polarization use

[0060] When full polarization is used, VV / VH / HH / HV is used as an example to illustrate the transmission phase of the first PRT. Figure 2 In the middle, switch 1 is set to V polarization; in the receiving stage of the first PRT, switch 1 is set to V polarization; in the transmitting stage of the second PRT, switch 1 is set to V polarization; in the receiving stage of the second PRT, switch 1 is set to H polarization; in the transmitting stage of the third PRT, switch 1 is set to H polarization; in the receiving stage of the third PRT, switch 1 is set to H polarization; in the transmitting stage of the fourth PRT, switch 1 is set to H polarization, and in the receiving stage of the fourth PRT, switch 1 is set to V polarization. The subsequent polarization switching is repeated in the above manner, and the schematic diagram of polarization switching is shown as follows. Fig.10 shown.

[0061] This fully polarized SAR radio frequency network solves the following problems:

[0062] 1. Cost issue: Since the number of channels of the fully polarized SAR payload is twice that of the single-polarized SAR payload, the hardware cost is also greatly increased compared with the single-polarized SAR payload, and the corresponding testing cost and personnel cost will also be greatly increased;

[0063] 2. Cycle issue: Since the number of channels of the fully polarized SAR payload is twice that of the single-polarized SAR payload, the test cycle is also greatly increased compared with the single-polarized SAR payload.

[0064] 3. Weight issue: Since the number of channels of the fully-polarized SAR payload is twice that of the single-polarized SAR payload, the weight of the SAR payload is also greatly increased compared to the single-polarized SAR payload.

[0065] Advantages of the present invention:

[0066] 1. The present invention can significantly reduce costs, and the total cost is expected to be reduced by 30%;

[0067] 2. The present invention can greatly shorten the development cycle, and it is estimated that the development cycle can be shortened by 20%;

[0068] 3. The present invention can significantly reduce weight, and it is estimated that the overall weight of the load can be reduced by 20%.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fully polarized SAR radio frequency network, characterized in that: It includes a signal processing radio frequency network 1 and a signal processing radio frequency network 2. The signal processing radio frequency network 2 includes an antenna and a power division network, a calibration network and several TR components distributed therein. The power division network and the calibration network both communicate with the signal processing radio frequency network 1 in a two-way manner. Each interface of the power division network and the calibration network corresponds to the same TR component, and each TR component is connected to a polarization port of the antenna. The working mode of the radio frequency network includes imaging / calibration tasks and polarization working modes, wherein the imaging / calibration tasks include imaging tasks, reference calibration tasks, transmission calibration tasks and reception calibration tasks; the polarization working modes include single polarization polarization switching modes, dual polarization polarization switching modes and full polarization polarization switching modes; The signal processing radio frequency network 1 includes a transmitter, a driving power amplifier, a radar coupler, a power amplifier, a radar circulator, a limiter, three switch arrays and a receiver. The transmitter is connected to port 1 of the radar coupler through the driving power amplifier, port 3 of the radar coupler is connected to a switch array, the switch array is respectively connected to the receiver and the fixed attenuator through two switch arrays, port 2 of the radar coupler is connected to port 1 of the radar circulator through the power amplifier, the power division network is connected to port 2 of the radar circulator, and port 3 of the radar circulator is connected to the receiver through the limiter and a switch array.

2. The fully polarized SAR radio frequency network according to claim 1, characterized in that: Each of the TR components includes two TR switches, a transmitting branch, a receiving branch, a TR coupler and switch one. The transmitting branch and the receiving branch are connected between the two TR switches. One TR switch is connected to the power division network, and the other TR switch is connected to the antenna through the TR coupler and switch one in sequence. The TR coupler is also connected to the calibration network.

3. The fully polarized SAR radio frequency network according to claim 2, characterized in that: The signal path for the imaging task includes: During the transmission of the imaging mission signal, the transmission signal is sent from the transmitter, and after driving the power amplifier, the radar coupler, and the power amplifier, it reaches the port 1 of the radar circulator, and is output from the port 2 of the radar circulator to the power division network, and then output from the power division network to the transmission branch of each TR component, and finally output to the antenna through the switch 1 selection; During the reception of imaging mission signals, the echo signal is polarized through switch 1, and the selection signal is output to the power division network through the receiving branches of each TR component, and then output to the receiver through the radar circulator, limiter and switch matrix to complete the signal reception.

4. The fully polarized SAR radio frequency network according to claim 2, characterized in that: The signal path of the reference calibration task includes: For the reference calibration task, the calibration signal is sent from the transmitter, output to two switch matrices through the radar coupler port 3, and then output to the receiver after selection by the switch matrix to complete the reference calibration signal reception.

5. The fully polarized SAR radio frequency network according to claim 2, characterized in that: The signal path of the transmit calibration task includes: During the transmission calibration task, the transmission signal is sent out from the transmitter, passes through the driver amplifier, radar coupler, and power amplifier, and then enters the radar circulator. It is then output to the power division network and TR component through the radar circulator. The transmission calibration signal passes through the transmission branch of the TR component and is output to the calibration network through the TR coupler. It is then selected through the fixed attenuator and switch matrix and output to the receiver.

6. The fully polarized SAR radio frequency network according to claim 2, characterized in that: The signal path for receiving the calibration task includes: During the receiving calibration task, the calibration signal is sent out from the transmitter, passes through the driver amplifier, the three ports of the radar coupler, the switch matrix, and the fixed attenuator, and then is output to the calibration network. Then, it passes through each TR coupler and the receiving branch and is output to the power division network for combining. After passing through the radar circulator and limiter, it is selected by the switch matrix to be received by the receiver, thus completing the reception of the calibration signal.

7. The fully polarized SAR radio frequency network according to claim 2, characterized in that: The single polarization polarization switching modes include: When single polarization is used, if V polarization is selected, switch 1 selects V polarization in both the transmitting state and the receiving state, and the settings of the remaining switches are selected according to the imaging / calibration task.

8. The fully polarized SAR radio frequency network according to claim 2, characterized in that: Dual polarization switching modes include: When dual polarization is used, if VV / HH polarization is selected, each PRT of switch 1 switches polarization in turn, the current PRT selects V polarization, and the next PRT selects H polarization; the polarization of the transmit and receive state switch 1 in each PRT is not switched.

9. The fully polarized SAR radio frequency network according to claim 2, characterized in that: Full polarization switching modes include: When full polarization is used, if VV / VH / HH / HV polarization is selected, then in the transmitting stage of the first PRT, switch 1 is set to V polarization; in the receiving stage of the first PRT, switch 1 is set to V polarization; in the transmitting stage of the second PRT, switch 1 is set to V polarization; in the receiving stage of the second PRT, switch 1 is set to H polarization; in the transmitting stage of the third PRT, switch 1 is set to H polarization; in the receiving stage of the third PRT, switch 1 is set to H polarization; in the transmitting stage of the fourth PRT, switch 1 is set to H polarization, and in the receiving stage of the fourth PRT, switch 1 is set to V polarization; the subsequent polarization switching is repeated in the above manner.

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