CN103647592B - A kind of signal acceptance method and equipment - Google Patents
A kind of signal acceptance method and equipment Download PDFInfo
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- CN103647592B CN103647592B CN201310747116.7A CN201310747116A CN103647592B CN 103647592 B CN103647592 B CN 103647592B CN 201310747116 A CN201310747116 A CN 201310747116A CN 103647592 B CN103647592 B CN 103647592B
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Abstract
The application provides a kind of signaling method, method of reseptance and equipment.Wherein signaling method includes：Generate carrier signal of the frequency for medium and low frequency；The data for needing to send in transmission equipment are packaged into message；Data in message are encoded, the code stream after being encoded；Code stream after coding is modulated in carrier signal, obtains at least one signal bit stream, wherein the frequency of signal bit stream and the frequency of carrier signal identical；At least one signal bit stream is amplified, obtains at least one RFID signal；In the transmission time slot for sending equipment itself, control the transmission of RFID signal according to control signal.As RFID signal is medium and low frequency, when the RFID signal of medium and low frequency is transmitted through barrier indoors, its stability is better than the RFID signal of hyperfrequency and microwave, and then is carried out positioning its precision higher than being positioned using the RFID signal of hyperfrequency and microwave using the RFID signal of the medium and low frequency.
Description
Technical Field
The present invention relates to the field of RFID (Radio Frequency IDentification), and in particular, to a signal transmitting method, a signal receiving method, and a device.
Background
The RFID technology is a communication technology for identifying an electronic tag by a radio signal and reading and writing related data without establishing mechanical or optical contact between an identification system and the electronic tag. Due to the advantages of non-contact and non-line-of-sight of the RFID technology, the RFID technology has become a preferred indoor positioning technology.
Currently, the indoor positioning using the RFID technology mainly uses RSSI (Received Signal strength indication) ranging, and the process may be as follows: firstly, a plurality of RFID receivers receive RFID signals sent by the electronic tags, secondly, each RFID receiver converts RSSI values in the RFID signals into distance information, and finally, the position of the electronic tags is calculated by utilizing a three-point positioning principle. After the position information of the electronic tag is acquired, the motion track of the electronic tag in a certain area can be calculated, so that the electronic tag can be positioned and tracked in real time.
From the above processing procedure, it can be derived that the accuracy of ranging is crucial to the accuracy of the whole processing procedure. Currently, the RFID technology mainly utilizes four frequency bands for positioning: medium and low frequencies (125 KHz to 225 KHz), high frequencies (13.56 MHz (Mega Hertz)), ultra high frequencies (433/868/915 MHz), and microwaves (2.4/5.8 GHz (GigaHertz)), wherein ultra high frequencies and microwaves are mainly used in indoor positioning.
When the RFID signal passes through the obstacle indoors, the signal power can be attenuated due to the scattering of the obstacle on the RFID signal, so that the RSSI of the RFID signal is greatly different indoors and outdoors, and even in a complex indoor environment, the RFID signal can be blocked by a shadow effect. Due to the high self frequency and the short signal wavelength of the ultrahigh frequency and the microwave, the scattering phenomenon of the RFID signal in the propagation process is serious, so that the multipath path effect is enhanced, the attenuation of the RFID signal in the propagation of a complex indoor environment is increased, and the indoor environment cannot be accurately positioned.
Disclosure of Invention
The technical problem to be solved by the present application is to provide a signal sending method, a signal receiving method and a device, so as to solve the problem that in the prior art, an RFID signal using ultra-high frequency and microwave cannot be accurately positioned in an indoor environment. The technical scheme is as follows:
the embodiment of the application provides a signal sending method, which comprises the following steps:
generating a carrier signal having a medium to low frequency in the range of 125khz to 225 khz;
packaging data to be sent in sending equipment into a message, wherein the sending equipment is used for sending a radio frequency identification signal, and the radio frequency identification signal is used for triggering an electronic tag to enter a working state;
coding the data in the message to obtain a coded code stream;
modulating the coded code stream to the carrier signal with the medium-low frequency to obtain at least one code stream signal, wherein the frequency of the code stream signal is the same as that of the carrier signal;
amplifying the at least one code stream signal to obtain at least one radio frequency identification signal;
and controlling the sending of the radio frequency identification signal according to the control signal in the sending time slot of the sending equipment.
Preferably, the carrier signal has a frequency of 125 kilohertz.
Preferably, modulating the coded code stream to the carrier signal with the medium-low frequency to obtain at least one code stream signal, including: and loading the coded code stream onto the carrier signal by adopting a binary on-off keying modulation mode to obtain a code stream signal.
Preferably, encoding the data in the message to obtain an encoded code stream, includes: and carrying out Manchester encoding on the data in the message to obtain a code stream.
Preferably, before generating a carrier signal with a medium-low frequency, the method further comprises: determining a transmission time slot for the transmitting device, wherein the length of the transmission time slot is 40 milliseconds.
The embodiment of the present application further provides a signal receiving method, including:
receiving a radio frequency identification signal by using a three-axis antenna;
acquiring a received signal strength indicating value of the radio frequency identification signal;
when it is determined that the frequency of a carrier signal corresponding to the radio frequency identification signal is the same as the frequency of a carrier signal generated by a sending device, and a synchronization word in the radio frequency identification signal is the same as the synchronization word of the sending device, decoding a data stream after the synchronization word in the radio frequency identification signal to obtain decoded data;
and transmitting the received signal strength indication value and the decoded data.
Preferably, the obtaining of the received signal strength indication value of the radio frequency identification signal comprises:
performing automatic gain control on the radio frequency identification signals received by the three channels of the triaxial antenna to obtain three radio frequency identification signals after automatic gain control;
selecting a radio frequency identification signal with the optimal signal intensity from the three radio frequency identification signals for caching;
when at least six radio frequency identification signals are cached, selecting six radio frequency identification signals with the optimal signal intensity from the at least six radio frequency identification signals, and taking the signal intensity of each radio frequency identification signal as a received signal intensity indicated value of the corresponding radio frequency identification signal;
when the six radio frequency identification signals are not cached, all the cached radio frequency identification signals are selected, and the signal intensity of each radio frequency identification signal is used as a received signal intensity indicated value of the corresponding radio frequency identification signal.
Preferably, decoding a data stream following a sync word in the radio frequency identification signal to obtain decoded data includes:
and performing Manchester decoding on the data stream after the synchronous word in the radio frequency identification signal to obtain decoded data.
An embodiment of the present application further provides a signal transmission device, including:
the single chip microcomputer is used for generating a carrier signal with middle and low frequency, packaging data to be transmitted in signal transmitting equipment into a message, encoding the data in the message to obtain an encoded code stream, modulating the encoded code stream onto the carrier signal with the middle and low frequency to obtain at least one code stream signal, wherein the middle and low frequency range is 125-225 KHz, the signal transmitting equipment is used for transmitting a radio frequency identification signal, the radio frequency identification signal is used for triggering an electronic tag to enter a working state signal, and the frequency of the code stream signal is the same as that of the carrier signal;
the amplifying circuit is used for amplifying the at least one code stream signal to obtain at least one radio frequency identification signal;
and the transmitting antenna is used for controlling the transmission of the radio frequency identification signal according to the control signal in the self transmitting time slot of the transmitting equipment.
An embodiment of the present application further provides a signal receiving apparatus, including:
a triaxial antenna for receiving a radio frequency identification signal;
the single chip microcomputer is used for acquiring a received signal strength indicating value of the radio frequency identification signal, and decoding a data stream after a synchronous word in the radio frequency identification signal to obtain decoded data when it is determined that a carrier signal corresponding to the radio frequency identification signal is the same as the frequency of a carrier signal generated by sending equipment and the synchronous word in the radio frequency identification signal is the same as the synchronous word in the sending equipment;
a transmitting antenna for transmitting the received signal strength indication value and the decoded data.
Compared with the prior art, the method has the following advantages:
the signal transmission method provided by the embodiment of the application can firstly generate a carrier signal with a medium-low frequency, and obtain the RFID signal on the basis of the carrier signal with the medium-low frequency, wherein the RFID signal is obtained by amplifying a code stream signal with the same frequency as the carrier signal, so that the frequency of the RFID signal is still the medium-low frequency. The low-medium frequency RFID signal has longer wavelength, can fully inhibit the scattering effect, and can pass through the obstacle through the diffraction effect when encountering the obstacle, so that the stability of the low-medium frequency RFID signal is superior to that of the ultrahigh frequency and microwave RFID signal when the low-medium frequency RFID signal is transmitted indoors through the obstacle, and the positioning accuracy of the low-medium frequency RFID signal is higher than that of the ultrahigh frequency and microwave RFID signal.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
Fig. 1 is a flowchart of a signal transmission method according to an embodiment of the present application;
fig. 2 is a flowchart of a signal receiving method according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a signal transmitting device according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a signal receiving apparatus according to an embodiment of the present application.
Detailed Description
First, a signal transmission method and a signal reception method provided in an embodiment of the present application are briefly described, where the signal transmission method provided in the embodiment of the present application may include:
generating a carrier signal having a medium to low frequency in the range of 125khz to 225 khz;
packaging data to be sent in sending equipment into a message, wherein the sending equipment is used for sending a radio frequency identification signal, and the radio frequency identification signal is used for triggering an electronic tag to enter a working state;
coding the data in the message to obtain a coded code stream;
modulating the coded code stream to the carrier signal with the medium-low frequency to obtain at least one code stream signal, wherein the frequency of the code stream signal is the same as that of the carrier signal;
amplifying the at least one code stream signal to obtain at least one radio frequency identification signal;
and controlling the sending of the radio frequency identification signal according to the control signal in the sending time slot of the sending equipment.
Correspondingly, a signal receiving method provided in an embodiment of the present application includes:
receiving a radio frequency identification signal by using a three-axis antenna;
acquiring a received signal strength indicating value of the radio frequency identification signal;
when it is determined that the frequency of a carrier signal corresponding to the radio frequency identification signal is the same as the frequency of a carrier signal generated by a sending device, and a synchronization word in the radio frequency identification signal is the same as the synchronization word of the sending device, decoding a data stream after the synchronization word in the radio frequency identification signal to obtain decoded data;
and transmitting the received signal strength indication value and the decoded data.
In the signal transmission method, the RFID signal is obtained on the basis of the carrier signal with the medium and low frequency, and is obtained by amplifying the code stream signal with the same frequency as the carrier signal, so that the frequency of the RFID signal is still the medium and low frequency. The low-medium frequency RFID signal has longer wavelength, can fully inhibit the scattering effect, and can pass through the obstacle through the diffraction effect when encountering the obstacle, so that the stability of the low-medium frequency RFID signal is superior to that of the ultrahigh frequency and microwave RFID signal when the low-medium frequency RFID signal is transmitted indoors through the obstacle, and the positioning accuracy of the low-medium frequency RFID signal is higher than that of the ultrahigh frequency and microwave RFID signal.
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, a flowchart of a signal sending method provided in an embodiment of the present application is shown, where the method includes the following steps:
step 101: a carrier signal is generated at a medium to low frequency.
In the embodiment of the present application, the medium and low frequencies range from 125KHz to 225 KHz. Because the wavelength of the carrier signal of 125KHz is greater than the wavelengths of other carrier signals in the medium-low frequency range, and the stability of the barrier crossing of the carrier signal is superior to that of other carrier signals in the medium-low frequency range, the carrier signal with the frequency of 125KHz is preferred in the embodiment of the application.
Step 102: and encapsulating data to be sent in sending equipment into a message, wherein the sending equipment is used for sending an RFID signal, and the RFID signal is used for triggering the electronic tag to enter a working state.
Since the RFID signal is used to trigger the electronic tag to enter an operating state and the electronic tag needs to know which sending device sent the RFID signal, the data that the sending device needs to send may include a flag identifying the sending device. Since each device has a unique identification number, in the embodiment of the present application, the device can be identified by using the unique identification number of the device. The corresponding RFID signal includes the identification number of the transmitting device.
Further, the data to be sent by the sending device may further include a Cyclic Redundancy Check (CRC) code, where the CRC code is obtained by calculating an identification number of the device, so as to avoid that the identification number of the device is changed, which may result in an error in positioning the electronic tag.
When data is encapsulated, the data can be encapsulated according to the existing protocol format, and the message format obtained after encapsulation can be as follows: preamble + sync word + identification number + check code. Where the preamble is the start of a message, which may include information such as the header of the message, the sync word is used to avoid interference with other signals, and the receiving device decodes the data following the sync word only after receiving a valid sync word. Certainly, the packet obtained by encapsulating the data in the embodiment of the present application may also be in other formats, and the embodiment of the present application is not described one by one.
Step 103: and coding the data in the message to obtain a coded code stream.
The data in the message may be encoded using existing encoding techniques, preferably manchester encoding, to obtain a code stream of sequence 01010100001111, i.e., 0/1. The reason why manchester is selected for encoding is that: the clock signal can be coded into the code stream by coding in Manchester, so that the receiving equipment can conveniently and directly recover the clock signal from the code stream; on the other hand, the frequency spectrum transmitted by the code stream can be further balanced after coding, so that the efficiency of the frequency spectrum is improved, wherein the clock signal is used for adjusting the clocks of the sending device and the receiving device, and the clock reference between the sending device and the receiving device is synchronized.
On the premise that the clock reference is synchronized, different sending time slots are further distributed for different sending devices, so that each sending device can send RFID signals in the sending time slot of the sending device, and interference among the RFID signals is avoided.
Further, each sending device actually covers a space ball with a certain distance as a radius, the whole indoor space is formed by splicing a plurality of space balls, if a plurality of sending devices send RFID signals at the same time, the RFID signals are damaged due to mutual collision among the plurality of RFID signals, and then transmission is invalid, so that different sending time slots are distributed for different sending devices on the premise that clock references are synchronized, and each sending device can send the RFID signals in the sending time slot of the sending device, so that collision among the RFID signals is avoided. In the embodiment of the present invention, the length of the transmission time slot of each transmitting device is 40ms, and this value can satisfy the distribution requirement of the transmission time between the transmitting devices.
Step 104: and modulating the coded code stream to a carrier signal with a medium-low frequency to obtain at least one code stream signal, wherein the frequency of the code stream signal is the same as that of the carrier signal.
In the embodiment of the present application, the code stream may be modulated by using an existing mature modulation technique, such as an FSK (Frequency-Shift Keying) modulation scheme or an OOK (On-Off Keying) modulation scheme. When an OOK modulation mode is adopted, a code stream signal can be obtained; when the FSK modulation mode is adopted, at least 2 code stream signals with different frequency points can be generated.
Since the receiving device corresponding to the transmitting device is generally carried around, and is required to be small in size, and the service life of the receiving device is required to be at least two years when the receiving device is powered by a battery, the receiving device needs to have the characteristics of small size and low power consumption, which means that the signal processing time of the receiving device needs to be shortened.
Because the transmission time of the code stream signal obtained by adopting other modulation modes such as FSK is longer than that of the code stream signal obtained by adopting OOK modulation, and the power consumption of the receiving equipment is larger than that of the receiving equipment obtained by adopting OOK demodulation when the receiving equipment uses other modulation modes such as FSK, the power consumption of the receiving equipment is small when the receiving equipment receives the code stream signal obtained by adopting OOK modulation, and further, the embodiment of the application preferably adopts the OOK modulation mode to obtain one code stream signal.
Step 105: and amplifying at least one code stream signal to obtain at least one RFID signal.
When the code stream signal is amplified, two-stage amplification can be adopted, namely the code stream signal is amplified by a first-stage push-pull power amplification circuit and a second-stage push-pull power amplification circuit in sequence, so that the amplification power of the RFID signal is improved.
Step 106: and controlling the transmission of the RFID signal according to the control signal in the transmission time slot of the transmission equipment.
In the embodiment of the invention, the control signal is a square wave sequence with a baud rate of 4096, under the square wave sequence, when the square wave sequence is at a high level, the RFID signal is output, and when the square wave sequence is at a low level, the RFID signal is forbidden to be output.
The control signal may be directly generated by one signal generator, or may be generated in other manners, for example, in a two-stage control manner, as follows:
firstly, manchester encoding is carried out on data in a message, 01010100001111, namely a 0/1 sequence is generated after encoding, and meanwhile, a square wave signal with the frequency of 4096 is generated by a sending device; and secondly, performing AND operation on the sequence obtained after coding and the square wave signal to generate a square wave sequence with the baud rate of 4096, and taking the square wave sequence as a control signal.
By applying the technical scheme, the RFID signal is obtained on the basis of the carrier signal with the medium and low frequency, and is obtained by amplifying the code stream signal with the same frequency as the carrier signal, so that the frequency of the RFID signal is still the medium and low frequency. The low-medium frequency RFID signal has longer wavelength, can fully inhibit the scattering effect, and can pass through the obstacle through the diffraction effect when encountering the obstacle, so that the stability of the low-medium frequency RFID signal is superior to that of the ultrahigh frequency and microwave RFID signal when the low-medium frequency RFID signal is transmitted indoors through the obstacle, and the positioning accuracy of the low-medium frequency RFID signal is higher than that of the ultrahigh frequency and microwave RFID signal.
Correspondingly, an embodiment of the present application further provides a signal receiving method, where the signal receiving method may be applied to receiving devices such as an electronic tag, and a flowchart thereof may refer to fig. 2, and may include the following steps:
step 201: and receiving the RFID signal by adopting a triaxial antenna.
The triaxial antenna is an xyz three-channel three-dimensional receiving antenna, and each channel can receive RFID signals, so that the field intensity in each direction can be ensured to be constant, the point position field intensity of receiving equipment can be restored to the maximum extent, and the problem of directivity of the signals in the receiving process is solved.
Step 202: and acquiring the RSSI value of the RFID signal.
After receiving the RFID signal, the RSSI value of the RFID signal may be directly obtained, or the RSSI value may also be obtained after processing the RFID signal, which is specifically as follows:
after receiving an RFID signal, the triaxial antenna performs automatic gain control on the RFID signal in each channel, selects an RFID signal with the optimal signal intensity from the three RFID signals after automatic gain control, and caches the RFID signal in the buffer.
Further, in an actual scene, at least six transmitting devices are installed in the coverage area of the RFID signal, and different transmitting devices transmit the RFID signal in different time slots, so that the receiving device can sequentially receive the RFID signals transmitted by the at least six transmitting devices by using a triaxial antenna. After performing gain processing on each received RFID signal, at least six RFID signals may be buffered in the buffer.
When at least six RFID signals are cached, six RFID signals with the optimal signal intensity are selected from the at least six RFID signals, and the signal intensity of each RFID signal is used as the RSSI value of the corresponding RFID signal; and when the six RFID signals are not cached, selecting all cached RFID signals, and taking the signal strength of each RFID signal as the RSSI value of the corresponding RFID signal.
Step 203: and when the carrier signal corresponding to the RFID signal is determined to be the same as the frequency of the carrier signal generated by the sending equipment, and the synchronous word in the RFID signal is determined to be the same as the synchronous word in the sending equipment, decoding the data stream after the synchronous word in the RFID signal to obtain the decoded data.
The transmitting device preferably employs manchester for encoding, and the corresponding receiving device employs manchester for decoding.
Step 204: and transmitting the RSSI value and the decoded data.
The receiving device sends the RSSI value and the decoded data to the background server, and the background server locates the receiving device, such as an electronic tag, according to the RSSI value and the decoded data, and the specific process may be:
the decoded data comprises the identification number of the sending device and the identification number of the receiving device, further the background server can obtain the RSSI value corresponding to the identification number of the same receiving device, then the RSSI value is converted into distance information, and finally the position of the receiving device is calculated by utilizing the three-point positioning principle.
Of course, the process of positioning the receiving device by the backend server may also be completed by the receiving device itself, and the embodiment of the present application is not limited thereto.
The transmitting equipment transmits a low-medium frequency RFID signal, and the stability of the low-medium frequency RFID signal is superior to that of ultrahigh frequency and microwave RFID signals when the low-medium frequency RFID signal is transmitted through obstacles indoors, so that the stability of the RFID signal received by the receiving equipment is higher than that of the ultrahigh frequency and microwave RFID signals, the accuracy is improved when the RFID signal is used for positioning, and the problem of low accuracy when the high-frequency and microwave RFID signals are used for positioning is solved.
The RFID signals obtained by the signal sending method provided by the embodiment of the invention pass signal transmission tests, the farthest transmission can reach 12M, and the receiving equipment can process about 1000 RFID signals in an indoor space, which is far greater than the processing of 100 RFID signals in the current market.
With reference to the signal sending method shown in fig. 1, an embodiment of the present application further provides a signal sending device, whose schematic structural diagram please refer to fig. 3, which may include: singlechip 11, amplifier circuit 12 and transmitting antenna 13. Wherein,
the single chip microcomputer 11 is configured to generate a carrier signal with a medium-low frequency, encapsulate data to be transmitted in the signal transmission device into a message, encode the data in the message to obtain an encoded code stream, and modulate the encoded code stream onto the carrier signal with the medium-low frequency to obtain at least one code stream signal.
The medium-low frequency range is 125KHz to 225KHz, and as the wavelength of the carrier signal of 125KHz is greater than the wavelengths of other carrier signals in the medium-low frequency range, the stability of the barrier crossing of the carrier signal is superior to that of other carrier signals in the medium-low frequency range, the carrier signal with the frequency of 125KHz is preferred in the embodiment of the application.
The data to be transmitted by the signal transmission device includes: the RFID signal transmitting device comprises an identification number of the device and a CRC code, wherein the identification number of the device is used for identifying which RFID signal transmitting device the signal is transmitted, and the CRC code can verify whether the identification number of the device is changed or not, so that errors of positioning the electronic tag are avoided. The RFID signal is used for triggering the electronic tag to enter a working state signal.
When data is encapsulated, the data can be encapsulated according to the existing protocol format, and the message format obtained after encapsulation can be as follows: preamble + sync word + identification number + check code. Where the preamble is the start of a message, which may include information such as the header of the message, the sync word is used to avoid interference from other signals, and the receiving device decodes the data following the sync word only after receiving a valid sync word. Certainly, the packet obtained by encapsulating the data in the embodiment of the present application may also be in other formats, and the embodiment of the present application is not described one by one.
Further, the data in the message may be encoded by using an existing encoding technique, preferably manchester encoding.
In the embodiment of the present application, the code stream may be modulated by using an existing relatively mature modulation technique, such as an FSK modulation method or an OOK modulation method. When an OOK modulation mode is adopted, a code stream signal can be obtained; when the FSK modulation mode is adopted, at least 2 code stream signals with different frequency points can be generated.
Since the receiving device corresponding to the transmitting device is generally carried around, and is required to be small in size, and the service life of the receiving device is required to be at least two years when the receiving device is powered by a battery, the receiving device needs to have the characteristics of small size and low power consumption, which means that the signal processing time of the receiving device needs to be shortened.
Because the transmission time of the code stream signal obtained by adopting other modulation modes such as FSK is longer than that of the code stream signal obtained by adopting OOK modulation, and the power consumption of the receiving equipment is larger than that of the receiving equipment obtained by adopting OOK demodulation when the receiving equipment uses other modulation modes such as FSK, the power consumption of the receiving equipment is small when the receiving equipment receives the code stream signal obtained by adopting OOK modulation, and then the embodiment of the application preferably adopts the OOK modulation mode to obtain a code stream signal, wherein the frequency of the code stream signal is the same as the frequency of the carrier signal.
And the amplifying circuit 12 is used for amplifying at least one code stream signal to obtain at least one RFID signal. The amplifying circuit 12 can adopt two-stage amplification, that is, the code stream signal is amplified by a first-stage push-pull power amplifying circuit and a second-stage push-pull power amplifying circuit in sequence, so that the amplifying power of the RFID signal is improved.
And a transmission antenna 13 for controlling the transmission of the RFID signal according to the control signal in the transmission time slot of the transmission apparatus itself.
The sending device firstly adjusts a clock according to a clock signal, and synchronizes clock references between the sending device and the receiving device. On the premise that the clock reference is synchronized, different sending time slots are further distributed for different sending devices, so that each sending device can send RFID signals in the sending time slot of the sending device, and interference among the RFID signals is avoided.
In the embodiment of the invention, the control signal is a square wave sequence with a baud rate of 4096, under the square wave sequence, when the square wave sequence is at a high level, the RFID signal is output, and when the square wave sequence is at a low level, the RFID signal is forbidden to be output.
The control signal may be directly generated by one signal generator, or may be generated in other manners, for example, in a two-stage control manner, as follows:
firstly, manchester encoding is carried out on data in a message, 01010100001111, namely a 0/1 sequence is generated after encoding, and meanwhile, a square wave signal with the frequency of 4096 is generated by a sending device; and secondly, performing AND operation on the sequence obtained after coding and the square wave signal to generate a square wave sequence with the baud rate of 4096, and taking the square wave sequence as a control signal.
Corresponding to the signal receiving method shown in fig. 2, an embodiment of the present application further provides a signal receiving apparatus, which is shown in fig. 4 and includes: three-axis antenna 21, singlechip 22 and transmitting antenna 23. Wherein,
a triaxial antenna 21 for receiving RFID signals. The three-axis antenna is an xyz three-channel three-dimensional receiving antenna, and each channel can receive RFID signals, so that the field intensity in each direction is constant, and the point position field intensity of the receiving equipment is restored to the maximum extent.
The single chip microcomputer 22 is configured to acquire an RSSI value of the RFID signal, and decode a data stream after the sync word in the RFID signal to obtain decoded data when it is determined that the frequency of the carrier signal corresponding to the RFID signal is the same as the frequency of the carrier signal generated by the transmitting device and the sync word in the RFID signal is the same as the sync word of the transmitting device.
The process of acquiring the RSSI value by the single chip microcomputer 22 may be: performing automatic gain control on RFID signals received by three channels of the triaxial antenna to obtain three RFID signals after automatic gain control, and selecting one RFID signal with the optimal signal intensity from the three RFID signals for caching; when at least six RFID signals are cached, six RFID signals with the optimal signal intensity are selected from the at least six RFID signals, and the signal intensity of each RFID signal is used as the RSSI value of the corresponding RFID signal; and when the six RFID signals are not cached, selecting all cached RFID signals, and taking the signal strength of each RFID signal as the RSSI value of the corresponding RFID signal.
The signal transmitting device preferably employs manchester for encoding, and the corresponding signal receiving device employs manchester for decoding.
And a transmission antenna 23 for transmitting the received signal strength indication value and the decoded data. After obtaining the RSSI value and the decoded data, the signal receiving device is sent to the background server by the sending antenna 23, and the background server locates the signal receiving device, such as an electronic tag, according to the RSSI value and the decoded data, and please refer to the embodiment of the method shown in fig. 2 for the locating process of the background server.
Of course, the positioning of the signal receiving device can also be accomplished by the single chip 22 therein, and the embodiment of the present application is not limited to the specific operating device for positioning.
It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other. For the device-like embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
Finally, it should also be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
For convenience of description, the above devices are described as being divided into various units by function, and are described separately. Of course, the functionality of the units may be implemented in one or more software and/or hardware when implementing the present application.
The foregoing detailed description is directed to a signal sending method, a signal receiving method, and a device provided in the present application, and a specific example is applied in the present application to explain the principle and the implementation of the present application, and the description of the foregoing embodiment is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific implementation and application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.
Claims (3)
1. A signal receiving method, comprising:
receiving a radio frequency identification signal by using a three-axis antenna;
acquiring a received signal strength indicating value of the radio frequency identification signal;
when it is determined that the frequency of a carrier signal corresponding to the radio frequency identification signal is the same as the frequency of a carrier signal generated by a sending device, and a synchronization word in the radio frequency identification signal is the same as the synchronization word of the sending device, decoding a data stream after the synchronization word in the radio frequency identification signal to obtain decoded data;
transmitting the received signal strength indication value and the decoded data;
obtaining a received signal strength indicator value of the radio frequency identification signal, comprising:
performing automatic gain control on the radio frequency identification signals received by the three channels of the triaxial antenna to obtain three radio frequency identification signals after automatic gain control;
selecting a radio frequency identification signal with the optimal signal intensity from the three radio frequency identification signals for caching;
when at least six radio frequency identification signals are cached, selecting six radio frequency identification signals with the optimal signal intensity from the at least six radio frequency identification signals, and taking the signal intensity of each radio frequency identification signal as a received signal intensity indicated value of the corresponding radio frequency identification signal;
when the six radio frequency identification signals are not cached, all the cached radio frequency identification signals are selected, and the signal intensity of each radio frequency identification signal is used as a received signal intensity indicated value of the corresponding radio frequency identification signal.
2. The method of claim 1, wherein decoding the data stream following the sync word in the radio frequency identification signal to obtain decoded data comprises:
and performing Manchester decoding on the data stream after the synchronous word in the radio frequency identification signal to obtain decoded data.
3. A signal receiving apparatus, comprising:
a triaxial antenna for receiving a radio frequency identification signal;
the single chip microcomputer is used for acquiring a received signal strength indicating value of the radio frequency identification signal, and decoding a data stream after a synchronous word in the radio frequency identification signal to obtain decoded data when it is determined that a carrier signal corresponding to the radio frequency identification signal is the same as the frequency of a carrier signal generated by sending equipment and the synchronous word in the radio frequency identification signal is the same as the synchronous word in the sending equipment;
a transmitting antenna for transmitting the received signal strength indication value and the decoded data;
obtaining a received signal strength indicator value of the radio frequency identification signal, comprising:
performing automatic gain control on the radio frequency identification signals received by the three channels of the triaxial antenna to obtain three radio frequency identification signals after automatic gain control;
selecting a radio frequency identification signal with the optimal signal intensity from the three radio frequency identification signals for caching;
when at least six radio frequency identification signals are cached, selecting six radio frequency identification signals with the optimal signal intensity from the at least six radio frequency identification signals, and taking the signal intensity of each radio frequency identification signal as a received signal intensity indicated value of the corresponding radio frequency identification signal;
when the six radio frequency identification signals are not cached, all the cached radio frequency identification signals are selected, and the signal intensity of each radio frequency identification signal is used as a received signal intensity indicated value of the corresponding radio frequency identification signal.
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| CN116592898B (en) * | 2023-07-17 | 2023-10-03 | 武汉工程大学 | Indoor positioning method |
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