Passive sensing system

Abstract

The present invention provides a passive sensing system, which relates to the field of RFID. In the present invention, a passive sensing tag is installed on a substance to be detected. When the tag receives a polling signal from a signal processing device, based on the characteristic that the impedance of its own sensing antenna changes with the environment, the tag feeds back an echo signal to the signal processing device, the amplitude and phase of which change with the impedance of the sensing antenna and include the tag identity data. Thus, the signal processing device can send the currently fed-back echo signal of the same passive sensing tag and its pre-stored echo signal in the daily environment to a main control device. The main control device displays the currently corresponding echo signal and the pre-stored echo signal of the same passive sensing tag, enabling the user to know the identity data of the corresponding tag and the environmental change situation around it by comparing signals on the main control device side, and reducing the implementation cost of sensing communication.

Description

Technical Field

[0001] The present invention relates to the field of RFID (Radio Frequency Identification), and more particularly, to a passive sensing system. Background Art

[0002] RFID technology is a technology that uses radio communication links to communicate between a reader and a radio frequency identification tag. With the continuous development of RFID technology, the application of radio frequency identification tags has been greatly expanded. However, at present, the existing RFID technology still remains at the stage of only transmitting the identity data stored in the tag itself, and the potential functions of RFID technology have not been fully developed. Summary of the Invention

[0003] In view of this, an object of the present invention is to provide a passive sensing system that performs wireless communication through a passive sensing tag, enables the passive sensing tag to feedback its own identity data and the environmental change status around the tag without an external power supply, and correspondingly reduces the implementation cost of sensing communication.

[0004] To achieve the above object, the technical solutions adopted in the embodiments of the present invention are as follows:

[0005] In a first aspect, an embodiment of the present invention provides a passive sensing system, which includes a main control device, a signal processing device, and at least one passive sensing tag;

[0006] Each of the passive sensing tags is installed on a corresponding substance to be detected, and each of the passive sensing tags includes a sensing antenna, and the impedance of the sensing antenna changes with the change of the environment where the corresponding passive sensing tag is located;

[0007] The signal processing device is configured to send a polling signal to a target passive sensing tag and receive a target echo signal fed back by the target passive sensing tag based on the impedance change of its own sensing antenna, where the target echo signal includes the identity data of the corresponding target passive sensing tag;

[0008] The signal processing device is electrically connected to the main control device, and is configured to send the target echo signal fed back by the target passive sensing tag and the pre-stored echo signal of the target passive sensing tag in the daily environment to the main control device for display.

[0009] In an alternative embodiment, the signal processing device includes a processor, a radio frequency transceiver, and a reader antenna;

[0010] The processor is electrically connected to the radio frequency transceiver, and the radio frequency transceiver is electrically connected to the reader antenna. The processor controls the radio frequency transceiver to send a polling signal to the target passive sensing tag through the reader antenna and receive the target echo signal fed back by the target passive sensing tag.

[0011] In an optional embodiment, the signal processing device further includes a memory;

[0012] The memory is used to store the pre-stored echo signals corresponding to each passive sensing tag in the daily environment;

[0013] The processor is electrically connected to the memory, and is used to extract the pre-stored echo signal of the target passive sensing tag from the memory and send the pre-stored echo signal and the target echo signal to the main control device for display.

[0014] In an optional embodiment, the main control device includes a display screen;

[0015] The display screen is electrically connected to the processor of the signal processing device through an interface connection, and is used to display the pre-stored echo signal and the target echo signal transmitted by the processor.

[0016] In an optional embodiment, the main control device further includes an external control device;

[0017] The external control device is electrically connected to the processor of the signal processing device through a bus connection, and is used to send a user instruction to the processor to make the processor perform corresponding operations according to the user instruction.

[0018] In an optional embodiment, the external control device includes one or more combinations of a mouse, a keyboard, a touch display, and a remote control handle.

[0019] In an optional embodiment, the passive sensing tag further includes a tag chip, and the tag chip stores the identity data of the passive sensing tag where it is located;

[0020] The tag chip is electrically connected to the sensing antenna, and the sensing antenna is closely attached to the substance to be detected. The sensing antenna provides energy to the tag chip based on the received carrier signal from the signal processing device, and the tag chip feeds back an echo signal to the signal processing device through the sensing antenna.

[0021] In an optional embodiment, the radio frequency transceiver is a dual-channel transceiver device, and the signal processing device further includes a carrier cancellation circuit, a power amplifier, and a circulator;

[0022] The first transmission port of the radio frequency transceiver is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the first port of the circulator, and the second port of the circulator is connected to the reader antenna, wherein the first transmission port is used to output a polling signal;

[0023] The second transmission port of the radio frequency transceiver is connected to the first input end of the carrier cancellation circuit, the second input end of the carrier cancellation circuit is connected to the third port of the circulator, and the receiving port of the radio frequency transceiver is connected to the output end of the carrier cancellation circuit, wherein the second input end is used to receive the target echo signal obtained by the reader antenna, the second transmission port is used to output a carrier cancellation signal for the leakage carrier from the first transmission port of the radio frequency transceiver, and the output end of the carrier cancellation circuit is used to output the target echo signal after carrier cancellation.

[0024] In an alternative embodiment, the carrier cancellation circuit includes a combiner, a programmable gain controller, and a low noise amplifier;

[0025] The input end of the programmable gain controller is connected to the second transmission port, and the control end of the programmable gain controller is connected to the processor, wherein the processor is used to control the signal gain of the programmable gain controller;

[0026] The first input end of the combiner is connected to the third port of the circulator, the second input end of the combiner is connected to the output end of the programmable gain controller, the output end of the combiner is connected to the input end of the low noise amplifier, and the output end of the low noise amplifier is connected to the receiving port of the radio frequency transceiver.

[0027] In an alternative embodiment, the sensing antenna is made of an environment-sensitive material, wherein the environment-sensitive material includes one or a combination of a thermosensitive material, a photosensitive material, a humidity-sensitive material, a gas-sensitive material, a magnetic-sensitive material, and a sound-sensitive material.

[0028] The present invention has the following beneficial effects:

[0029] In the present invention, a passive sensing tag is installed on a substance to be detected. When the tag receives a polling signal from a signal processing device, based on the characteristic that the impedance of its own sensing antenna changes with the environment, an echo signal with an amplitude and phase varying with the impedance of the sensing antenna and including the identity data of the tag itself is fed back to the signal processing device. Thus, the signal processing device can send the currently fed-back echo signal of the same passive sensing tag and its pre-stored echo signal in the daily environment to a main control device. The main control device displays the current echo signal and the pre-stored echo signal corresponding to the same passive sensing tag, enabling the user to know the identity data of the corresponding tag and the environmental changes around it through signal comparison on the main control device side, and reducing the implementation cost of sensing communication.

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically gives preferred embodiments and, in conjunction with the accompanying drawings, detailed descriptions are as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 Schematic diagram of the system composition of the passive sensing system provided by the embodiment of the present invention;

[0033] Figure 2 For Figure 1 One of the schematic diagrams of the device composition of the signal processing device in

[0034] Figure 3 For Figure 1 Another schematic diagram of the device composition of the signal processing device in

[0035] Figure 4 For Figure 1 A third schematic diagram of the device composition of the signal processing device in

[0036] Figure 5 For Figure 1 Schematic diagram of the device composition of the passive sensing tag in

[0037] Icons: 10 - Passive sensing system; 100 - Signal processing device; 200 - Passive sensing tag; 300 - Master control device; 210 - Sensing antenna; 310 - Display screen; 320 - External control device; 110 - Processor; 120 - Radio frequency transceiver; 130 - Reader / writer antenna; 140 - Memory; 150 - Carrier cancellation circuit; 160 - Power amplifier; 170 - Circulator; 151 - Combiner; 152 - Program-controlled gain controller; 153 - Low-noise amplifier; 220 - Tag chip. Detailed implementation manners

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

[0040] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0041] The following will describe in detail some embodiments of the present invention with reference to the accompanying drawings. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0042] Please refer to Figure 1 , Figure 1It is a schematic diagram of the system composition of the passive sensing system 10 provided by an embodiment of the present invention. In the embodiment of the present invention, the passive sensing system 10 can realize the wireless communication of tags, enabling the tags to feedback their own identity data and the environmental change conditions around the tags without an external power supply, and correspondingly reducing the implementation cost of sensing communication.

[0043] Among them, the passive sensing system 10 includes a main control device 300, a signal processing device 100, and at least one passive sensing tag 200. The signal processing device 100 can communicate with at least one passive sensing tag 200 through a radio communication link.

[0044] In this embodiment, each passive sensing tag 200 is installed on the substance to be detected or marked corresponding to the detection requirement, and then transmits signals through the sensing antenna 210 included therein. Among them, the antenna impedance of the sensing antenna 210 included in each passive sensing tag 200 changes with the environmental conditions where the passive sensing tag 200 is located, resulting in changes in the signal amplitude and signal phase of the feedback signal when the corresponding passive sensing tag 200 performs signal feedback along with the environmental conditions.

[0045] In this embodiment, the signal processing device 100 can send a polling signal to the target passive sensing tag 200 and receive the target echo signal fed back by the target passive sensing tag 200 based on the impedance change of its own sensing antenna 210. Among them, the polling signal is used to instruct the corresponding passive sensing tag 200 to perform data feedback. The polling signal may include, but is not limited to, one or more combinations of a tag position positioning instruction, a tag operation detection instruction, and a tag data reading instruction. The tag position positioning instruction is used to instruct the corresponding passive sensing tag 200 to perform position positioning, the tag operation detection instruction is used to instruct the corresponding passive sensing tag 200 to detect its own operation status, and the tag data reading instruction is used to instruct the corresponding passive sensing tag 200 to extract the stored data for feedback. In addition, the signal processing device 100 can broadcast and send a carrier signal for providing energy, so that when each sensing antenna 210 receives the carrier signal emitted by the signal processing device 100, it uses the signal energy obtained by coupling as the energy for the operation of the passive sensing tag 200 where it is located.

[0046] In an implementation manner of this embodiment, when the signal processing device 100 sends a polling signal, it can load the identity data of the target passive sensing tag 200 targeted by the signal processing device 100 (i.e., the ID (Identity Document) information of the corresponding tag) into the polling signal. In this case, when a certain passive sensing tag 200 receives the polling signal from the signal processing device 100 through its own sensing antenna 210, it will ensure the operation of the passive sensing tag 200 with the energy carried by the received carrier signal, and determine whether its own identity data is consistent with the identity data of the target passive sensing tag 200 that needs to communicate in the polling signal.

[0047] When the identity data of the passive sensing tag 200 that receives the polling signal is consistent with the identity data of the target passive sensing tag 200 in the polling signal, the passive sensing tag 200 that receives the polling signal will feedback a target echo signal including its own identity data to the signal processing device 100 based on the change of the antenna impedance of its own sensing antenna 210. When the identity data of the passive sensing tag 200 that receives the polling signal is inconsistent with the identity data of the target passive sensing tag 200 in the polling signal, the passive sensing tag 200 that receives the polling signal will not feedback the corresponding echo signal.

[0048] In another implementation manner of this embodiment, when the signal processing device 100 sends a polling signal, it will not load the identity data of any specific passive sensing tag 200 into the polling signal, so that each passive sensing tag 200 that receives the polling signal can be used as a target passive sensing tag 200, and each passive sensing tag 200 that receives the polling signal will correspondingly feedback a target echo signal including its own identity data to the signal processing device 100, and the signal processing device 100 will automatically analyze the target echo signals feedback by each target passive sensing tag 200 according to the anti-collision algorithm.

[0049] In this embodiment, the signal processing device 100 is electrically connected to the main control device 300, and is configured to send the target echo signal fed back by the target passive sensing tag 200 and the pre-stored echo signal of the target passive sensing tag 200 in the daily environment to the main control device 300 for display. Among them, after receiving the target echo signal from the target passive sensing tag 200, the signal processing device 100 will correspondingly determine the pre-stored echo signal corresponding to the target passive sensing tag 200 from the pre-stored echo signals of all the passive sensing tags 200 stored in the daily environment, and then send the target echo signal and the pre-stored echo signal corresponding to the same passive sensing tag 200 to the main control device 300. The main control device 300 displays the target echo signal and the pre-stored echo signal corresponding to the same target passive sensing tag 200, so that the user can understand the differences in waveform, spectrum, amplitude, and phase of the two echo signals of the same passive sensing tag 200 through signal comparison on the side of the main control device 300, and thus determine the environmental change status around the corresponding tag according to the specific difference situation.

[0050] In the above process, the passive sensing tag 200 in the present invention does not need to separately construct a circuit for measuring the environmental change status or externally connect a hardware device for measuring the environmental change status. It can directly, based on the characteristic that its own antenna impedance changes with the change of the surrounding environment, when the tag receives a polling signal with a matching identity, feed back an echo signal whose amplitude and phase change with the impedance of the sensing antenna 210 and includes the tag's own identity data to the signal processing device 100, so that the signal processing device 100 can send the currently fed-back echo signal of the same passive sensing tag 200 and its pre-stored echo signal in the daily environment to the main control device 300. The main control device 300 displays the currently fed-back echo signal and the pre-stored echo signal corresponding to the same passive sensing tag 200, so that the user can know the identity data of the corresponding tag and the environmental change status around it through signal comparison on the side of the main control device 300, and reduce the implementation cost of sensing communication. Among them, the passive sensing tag 200 feeds back the environmental change status around the tag through the waveform condition of the echo signal itself without an external power supply.

[0051] Optionally, please refer to Figure 2 , Figure 2 is Figure 1 One of the schematic diagrams of the device composition of the signal processing device 100 in

[0052] The processor 110 is electrically connected to the RF transceiver 120, and the RF transceiver 120 is electrically connected to the reader / writer antenna 130, wherein the processor 110 controls the RF transceiver 120 to send a polling signal to the target passive sensor tag 200 through the reader / writer antenna 130, and receives a target echo signal fed back by the target passive sensor tag 200. The RF transceiver 120 may be a single-channel transceiver or a dual-channel transceiver.

[0053] The processor 110 and the RF transceiver 120 may be interconnected via an FMC (FPGA Mezzanine Card) onboard card holder, or directly interconnected on the same printed circuit board.

[0054] The processor 110 may be a Xilinx TM Zynq from Xilinx TM FPGA (Field Programmable Gate Array) is used as a signal processing device, and the Arm embedded in the FPGA is used TM Processor hard core, through Arm TM The processor hard core runs an embedded Ubuntu operating system to implement the functions of the processor 110 .

[0055] In addition, the main control device 300 includes a display screen 310, and the display screen 310 is electrically connected to the processor 110 of the signal processing device 100 through an interface connection, and is used to display the pre-stored echo signal and the target echo signal transmitted by the processor 110. In one implementation of this embodiment, the display screen 310 is electrically connected to the processor 110 through an HDMI (High Definition Multimedia Interface) interface.

[0056] The master control device 300 may further include an external control device 320. The external control device 320 is electrically connected to the processor 110 of the signal processing device 100 in a bus connection manner, and is used to send user instructions to the processor 110, so that the processor 110 performs corresponding operations according to the user instructions. Among them, the external control device 320 includes one or more combinations of a mouse, a keyboard, a touch display, and a remote control handle. The user instructions may be instructions for the user to select a target passive sensing tag 200, or may be to load or delete the identity data of a certain target passive sensing tag 200 in the polling signal, or may also be to switch the target echo signal and the pre-stored echo signal of another target passive sensing tag 200 displayed on the display screen 310. In an implementation manner of this embodiment, the external control device 320 is electrically connected to the processor 110 through a USB (Universal Serial Bus) bus.

[0057] Optionally, please refer to Figure 3 , Figure 3 is Figure 1 the second schematic diagram of the device composition of the signal processing device 100 in

[0058] Among them, the memory 140 is used to store the pre-stored echo signals corresponding to each passive sensing tag 200 in the daily environment. The processor 110 is electrically connected to the memory 140, and is used to extract the pre-stored echo signals of the target passive sensing tag 200 from the memory 140, and send the pre-stored echo signals and the target echo signals to the master control device 300 for display.

[0059] Optionally, please refer to Figure 4 , Figure 4 is Figure 1 the third schematic diagram of the device composition of the signal processing device 100 in

[0060] In this embodiment, the radio frequency transceiver 120 may use the agile transceiver chip AD9361 of Analog Devices, Inc. TM as a dual-channel radio frequency transceiver device.

[0061] Among them, the first transmission port of the radio frequency transceiver 120 is connected to the input end of the power amplifier 160, the output end of the power amplifier 160 is connected to the first port of the circulator 170, and the second port of the circulator 170 is connected to the reader antenna 130. The first transmission port is used to output a polling signal, so as to broadcast the polling signal through the power amplifier 160 and the circulator 170 via the reader antenna 130.

[0062] Among them, the second transmission port of the radio frequency transceiver 120 is connected to the first input end of the carrier cancellation circuit 150, the second input end of the carrier cancellation circuit 150 is connected to the third port of the circulator 170, and the receiving port of the radio frequency transceiver 120 is connected to the output end of the carrier cancellation circuit 150. The second input end is used to receive the target echo signal obtained by the reader antenna 130, and the carrier cancellation circuit 150 cancels the leakage carrier of the radio frequency transceiver 120 received by the reader antenna 130 from the first transmission port, so as to weaken the interference of the leakage carrier on the target echo signal of the target passive sensing tag 200. Among them, the second transmission port of the radio frequency transceiver 120 is used to output a carrier cancellation signal for the leakage carrier from the first transmission port of the radio frequency transceiver 120, and the output end of the carrier cancellation circuit 150 is used to output the target echo signal after carrier cancellation, where the leakage carrier is the polling signal and / or carrier signal emitted by the signal processing device 100 itself obtained through the reader antenna 130.

[0063] In this embodiment, the carrier cancellation circuit 150 includes a combiner 151, a programmable gain controller 152, and a low noise amplifier 153.

[0064] Among them, the input end of the programmable gain controller 152 of the carrier cancellation circuit 150 is used as its own first input end. The input end of the programmable gain controller 152 is connected to the second transmission port of the radio frequency transceiver 120, and the control end of the programmable gain controller 152 is connected to the processor 110. Among them, the processor 110 can be used to control the signal gain of the programmable gain controller 152.

[0065] Among them, the first input end of the combiner 151 of the carrier cancellation circuit 150 is used as its own second input end. The first input end of the combiner 151 is connected to the third port of the circulator 170, and the second input end of the combiner 151 is connected to the output end of the programmable gain controller 152.

[0066] Among them, the carrier cancellation circuit 150 uses the output terminal of the low-noise amplifier 153 as its own output terminal. The input terminal of the low-noise amplifier 153 is connected to the output terminal of the combiner 151, and the output terminal of the low-noise amplifier 153 is connected to the receiving port of the radio frequency transceiver 120.

[0067] Optionally, please refer to Figure 5 , Figure 5 is Figure 1 a schematic diagram of the device composition of the passive sensing tag 200 in

[0068] Among them, the tag chip 220 is electrically connected to the sensing antenna 210. The tag chip 220 can be used for signal transceiver and data storage. The passive sensing tag 200 can determine whether to respond to the received polling signal based on the tag chip 220, and when it is determined that a response is required, it feeds back an echo signal to the signal processing device 100. The tag chip 220 can be used to store the identity data of the passive sensing tag 200 where it is located. The sensing antenna 210 can provide energy to the tag chip 220 based on the received carrier signal from the signal processing device 100, and the tag chip 220 feeds back an echo signal to the signal processing device 100 through the sensing antenna 210.

[0069] In an implementation manner of this embodiment, the tag chip 220 can adopt an RFID chip compliant with the ISO18000-6C protocol.

[0070] Among them, the sensing antenna 210 is made of an environment-sensitive material to sense the change of the environment where the corresponding tag is located. The environment-sensitive material can include, but is not limited to, one or a combination of a thermosensitive material, a photosensitive material, a humidity-sensitive material, a gas-sensitive material, a magnetic-sensitive material, and a sound-sensitive material. Among them, the thermosensitive material can be used to detect the temperature change of the substance in contact with the sensing antenna 210, the photosensitive material can be used to detect the light change of the sensing antenna 210, the humidity-sensitive material can be used to detect the humidity change in the environment where the sensing antenna 210 is located, the gas-sensitive material can be used to detect the change of the gas composition in the environment where the sensing antenna 210 is located, the magnetic-sensitive material can be used to detect the change of the magnetic field strength in the environment where the sensing antenna 210 is located, and the sound-sensitive material can be used to detect the sound intensity change in the environment where the sensing antenna 210 is located.

[0071] In an implementation manner of this embodiment, when the passive sensing tag 200 is installed on a corresponding substance to be detected, the sensing antenna 210 is in close contact with the substance to be detected. The shape of the sensing antenna 210 can be a symmetric bending structure, a symmetric ring structure, or a symmetric circular or rectangular planar structure. The specific shape can be configured differently according to requirements.

[0072] In summary, in a passive sensing system provided by an embodiment of the present invention, the present invention installs a passive sensing tag on a substance to be detected. When the tag receives a polling signal from a signal processing device, based on the characteristic that the impedance of its own sensing antenna changes with the environment, it feeds back an echo signal to the signal processing device, the amplitude and phase of which change with the impedance of the sensing antenna and include the identity data of the tag itself. As a result, the signal processing device can send the currently fed-back echo signal of the same passive sensing tag and its pre-stored echo signal in a daily environment to a main control device. The main control device displays the currently received echo signal and the pre-stored echo signal corresponding to the same passive sensing tag, enabling a user to know the identity data of the corresponding tag and the environmental change status around it by comparing signals on the main control device side, and reducing the implementation cost of sensing communication. Among them, the passive sensing tag in the present invention can feed back its own identity data and the environmental change status around the tag without an external power supply.

[0073] The foregoing are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A passive sensing system, characterized in that, The system includes a main control device, a signal processing device, and at least one passive sensing tag; Each of the passive sensing tags is installed on a corresponding substance to be detected. Each of the passive sensing tags includes a sensing antenna and a tag chip. The tag chip stores the identity data of the passive sensing tag where it is located. The tag chip is electrically connected to the sensing antenna. The sensing antenna is closely attached to the substance to be detected. The sensing antenna provides energy to the tag chip based on the received carrier signal from the signal processing device. The sensing antenna is used to sense the environmental change status of the passive sensing tag where it is located. The impedance of the sensing antenna changes with the change of the environment of the corresponding passive sensing tag. The tag chip feeds back an echo signal to the signal processing device through the sensing antenna; The signal processing device is used to send a polling signal to a target passive sensing tag and receive a target echo signal fed back by the target passive sensing tag based on the impedance change of its own sensing antenna. The target echo signal includes the identity data of the corresponding target passive sensing tag. The target echo signal is an echo signal that matches the polling signal and whose corresponding signal amplitude and signal phase change with the impedance of the sensing antenna; The signal processing device is electrically connected to the main control device and is used to send the target echo signal fed back by the target passive sensing tag and the pre-stored echo signal of the target passive sensing tag in the daily environment to the main control device for display, so that the user can determine the environmental change status around the target passive sensing tag through signal comparison.

2. The system according to claim 1, characterized in that, The signal processing device includes a processor, a radio frequency transceiver, and a reader antenna; The processor is electrically connected to the radio frequency transceiver, and the radio frequency transceiver is electrically connected to the reader antenna. The processor controls the radio frequency transceiver to send a polling signal to a target passive sensing tag through the reader antenna and receive the target echo signal fed back by the target passive sensing tag.

3. The system according to claim 2, characterized in that, The signal processing device further includes a memory; The memory is used to store the pre-stored echo signal corresponding to each passive sensing tag in the daily environment; The processor is electrically connected to the memory and is used to extract the pre-stored echo signal of the target passive sensing tag from the memory and send the pre-stored echo signal and the target echo signal to the main control device for display.

4. The system according to claim 3, characterized in that, The main control device includes a display screen; The display screen is electrically connected to the processor of the signal processing device through an interface connection and is used to display the pre-stored echo signal and the target echo signal transmitted by the processor on the screen.

5. The system according to claim 4, characterized in that, The main control device further includes an external control device; The external control device is electrically connected to the processor of the signal processing device through a bus connection and is used to send a user instruction to the processor to make the processor perform corresponding operations according to the user instruction.

6. The system according to claim 5, characterized in that, The external control device includes one or more combinations of a mouse, a keyboard, a touch display, and a remote control handle.

7. The system according to any one of claims 2-6, characterized in that, The radio frequency transceiver is a dual-channel transceiver device, and the signal processing device further includes a carrier cancellation circuit, a power amplifier, and a circulator; The first transmission port of the radio frequency transceiver is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the first port of the circulator, and the second port of the circulator is connected to the reader antenna, wherein the first transmission port is used to output a polling signal; The second transmission port of the radio frequency transceiver is connected to the first input end of the carrier cancellation circuit, the second input end of the carrier cancellation circuit is connected to the third port of the circulator, and the receiving port of the radio frequency transceiver is connected to the output end of the carrier cancellation circuit, wherein the second input end is used to receive the target echo signal obtained by the reader antenna, the second transmission port is used to output a carrier cancellation signal for the leakage carrier from the first transmission port of the radio frequency transceiver, and the output end of the carrier cancellation circuit is used to output the target echo signal after carrier cancellation.

8. The system according to claim 7, characterized in that, The carrier cancellation circuit includes a combiner, a programmable gain controller, and a low noise amplifier; The input end of the programmable gain controller is connected to the second transmission port, and the control end of the programmable gain controller is connected to the processor, wherein the processor is used to control the signal gain of the programmable gain controller; The first input end of the combiner is connected to the third port of the circulator, the second input end of the combiner is connected to the output end of the programmable gain controller, the output end of the combiner is connected to the input end of the low noise amplifier, and the output end of the low noise amplifier is connected to the receiving port of the radio frequency transceiver.

9. The system according to claim 1, characterized in that, The sensing antenna is made of an environment-sensitive material, wherein the environment-sensitive material includes one or a combination of a thermosensitive material, a photosensitive material, a humidity-sensitive material, a gas-sensitive material, a magnetic-sensitive material, and a sound-sensitive material.

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