CN113030856A - RFID vehicle positioning system based on RSSI algorithm and positioning method thereof - Google Patents

RFID vehicle positioning system based on RSSI algorithm and positioning method thereof Download PDF

Info

Publication number
CN113030856A
CN113030856A CN202110311014.5A CN202110311014A CN113030856A CN 113030856 A CN113030856 A CN 113030856A CN 202110311014 A CN202110311014 A CN 202110311014A CN 113030856 A CN113030856 A CN 113030856A
Authority
CN
China
Prior art keywords
rssi
reader
distance
algorithm
vehicle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202110311014.5A
Other languages
Chinese (zh)
Inventor
张洁浩
李明洋
李磊德
陈继伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jiangxi Changhe Automobile Co Ltd
Original Assignee
Jiangxi Changhe Automobile Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Jiangxi Changhe Automobile Co Ltd filed Critical Jiangxi Changhe Automobile Co Ltd
Priority to CN202110311014.5A priority Critical patent/CN113030856A/en
Publication of CN113030856A publication Critical patent/CN113030856A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S11/00—Systems for determining distance or velocity not using reflection or reradiation
    • G01S11/02—Systems for determining distance or velocity not using reflection or reradiation using radio waves
    • G01S11/06—Systems for determining distance or velocity not using reflection or reradiation using radio waves using intensity measurements

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The invention discloses an RFID vehicle positioning system based on an RSSI algorithm and a positioning method thereof, which are characterized by comprising a positioning device, a reader and an electronic tag, wherein the positioning device comprises an RSSI weighting algorithm unit, the RSSI weighting algorithm unit is connected with a microcontroller, and the reader comprises an antenna, a reader chip, the microcontroller and a communication interface. According to the invention, the vehicle enters the parking lot provided with the reader with the radio frequency identification function, and the reader can position the vehicle through the electronic tag arranged on the vehicle, so that the information is not required to be manually input, and a custodian can automatically search the position of the vehicle and the information of the vehicle through a computer.

Description

RFID vehicle positioning system based on RSSI algorithm and positioning method thereof
Technical Field
The invention relates to the technical field of automobile positioning, in particular to an RFID (radio frequency identification) vehicle positioning system based on an RSSI (received signal strength indicator) algorithm and a positioning method thereof.
Background
When a vehicle enters a certain fixed area, the vehicle information can be identified only according to the license plate number, vehicles without license plates and special vehicles cannot be identified automatically, and the management system cannot identify the position of the vehicle in the area, so that the vehicle management and control are difficult.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides an RFID vehicle positioning system based on an RSSI algorithm, and solves the problem that the conventional vehicle brake has no cooling function, and the driving safety is easily caused by the brake overheating due to frequent and long-time braking.
In order to achieve the purpose, the invention adopts the technical scheme that:
the RFID vehicle positioning system based on the RSSI algorithm is characterized by comprising a positioning device, a reader and an electronic tag, wherein the positioning device comprises an RSSI weighting algorithm unit, the RSSI weighting algorithm unit is connected with a microcontroller, and the reader comprises an antenna, a reader chip, a microcontroller and a communication interface.
Preferably, the microcontroller is a CC2530 single chip microcomputer, the CC2530 single chip microcomputer includes a CPU, a storage unit, an on-chip and an off-chip and an RF radio frequency unit, the on-chip and the off-chip mainly include a 5-channel 8-bit to 14-bit programmable ADC converter, a timer, a USART, a DMA controller, an AES128 coprocessor, a watchdog, an internal voltage regulator, and a programmable I/O pin, and the programmable I/O pin may be configured as a general I/O pin.
Preferably, the CC2530 singlechip is in a receiving mode, and the current loss is lower than 27 mA; and in the emission mode, the current loss of the CC2530 single chip microcomputer is lower than 25 mA.
Preferably, the RSSI weighting algorithm unit adopts a binary 8-bit register, the value calculated by the RSSI weighting algorithm unit is an average value of power levels calculated for 8 cycles, an RF core in the CC2530 single chip microcomputer can transmit at 2405MHz, and the electronic tag transmission power is configured to 4.5 dBm.
An RFID vehicle positioning method based on an RSSI algorithm specifically comprises the following steps:
step one, installing a plurality of reference electronic tags and a plurality of readers in a parking lot;
step two, the electronic tag actively sends a Signal, and the reader acquires an RSSI (received Signal Strength indicator) value of the reference electronic tag;
step three, calculating a model adopted in wireless signal transmission, the signal strength received by a receiving end and the specific position of the vehicle in the system;
preferably, the model used in the wireless signal transmission considers the uplink of the reader and the tag-in according to the electromagnetic wave propagation theory, if the electronic tag radiates electromagnetic waves in a free space with a rated power, the received power or the field strength at any point in the theoretical space according to Friis transmission is only related to the distance, and in an actual environment, due to the existence of random factors such as multipath, obstacles, diffraction and the like, the model commonly used in the wireless signal transmission is as follows:
PL(d)＝PL(d0)+10nlog10(d/d0)+X0formula (1-1)
Wherein PL (d) is the path loss after a distance d, PL (d)0) For path loss after a unit distance, d0Is a unit distance, typically 1m, X0The average value is a random number of 0 and follows Gaussian distribution, the standard deviation range is 4-10, n is a signal attenuation factor, and the range is 2-4.
Preferably, in the second step, rssi (received Signal Strength indicator) is an indication of the Strength of the received Signal, and the Strength of the Signal received by the receiving end is:
PR(d)＝PT+GT-PL (d) formula (1-2)
In the formula, PR(d) Is the received signal strength, i.e. RSSI, PTTo transmit the power of the signal, GTFor transmit antenna gain, based on this principle, the ieee802.15.4 standard gives a simplified signal attenuation model:
Figure RE-GDA0003030195190000021
but considering factors such as environment, cost, positioning accuracy requirement and the like, the distance measurement model in actual measurement can be further simplified into
RSSI＝-10nlog10d-A Formula (1-4)
In the formula, n is a signal attenuation factor, the range is generally 2-4, and d is the distance between a positioning node and a reference node; a is an RSSI value measured when the distance d between the reader and the reference tag is 1m, the above formula is a classic model of RSSI ranging, and a functional relation between the RSSI and the d is obtained, so that the distance between the reader and the transmitter can be calculated by knowing the received RSSI value, A and n are empirical values and are related to specifically used hardware nodes and a wireless propagation environment, therefore, the values of A and n are different in different actual environments, the measurement is carried out in an actual parking lot, and the obtained ranging model is as follows:
RSSI＝-26log10d-38 type (1-5)
Developing upper computer software on a Windows system by using VB, and checking a received RSSI (received Signal Strength indicator) value.
Preferably, in step three, the system calculates the specific position of the vehicle, and the distances D from the tag to be measured to the three readers can be calculated by measuring the power of the radio wave from the electronic tag to the readers1、D2、D3Thus, the position of the electronic tag to be detected is respectively centered on the three readers D1、D2、D3At the intersection of circles of radius;
by classical trilateration, the coordinates corresponding to the three readers are respectively (x)1，y1)，(x2，y2)，(x3， y3) The intersection point D of the three circles is the position of the label to be positioned, the coordinate is (x, y), and the distance between the corresponding measuring point and the label to be measured is D1、d2、d3According to the geometrical relationship, the following can be known:
Figure RE-GDA0003030195190000031
subtracting the first two formulas from the last formula to obtain:
Figure RE-GDA0003030195190000032
the final position coordinates are obtained by the above formula:
Figure RE-GDA0003030195190000033
in the development and calculation software of Matlab on a Windows platform, RSSI values received by the same electronic tag on three readers and coordinate positions of the three readers are input into a system, so that the specific position of a vehicle can be calculated.
According to the invention, the vehicle enters the parking lot provided with the reader with the radio frequency identification function, and the reader can position the vehicle through the electronic tag arranged on the vehicle, so that the information is not required to be manually input, and a custodian can automatically search the position of the vehicle and the information of the vehicle through a computer.
Drawings
FIG. 1 is a schematic diagram of the apparatus of the present invention;
FIG. 2 is a schematic diagram of distances from a tag to be tested to three readers according to the present invention;
FIG. 3 is a schematic diagram of a system for calculating a specific position of a vehicle according to the present invention;
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
The CC2530 singlechip is a system-on-chip solution which is produced by Texas instruments and is special for communication of IEEE802.15.4 and Zigbee protocols. The chip size is small, the bottom hardware structure meets various technical requirements of Zigbee, few peripheral devices need to be added, and the cost is low, so that the chip is used as an ideal choice for positioning. The RF core is based on an industry leading radio frequency communication chip CC 2420. With a single chip integrated with a CPU, memory, usual on-chip peripherals and RF radio frequency units. The high-speed digital television receiver is provided with 1 8-bit CPU (8051), a main frequency of 32MHZ, a maximum 128KB programmable FLASH and 8KB SRAM, and the on-chip and the external equipment mainly comprise 1 5-channel 8-bit to 14-bit programmable ADC (analog to digital converter), 4 timers, 2 USARTs, 1 DMA (direct memory access) controller, 1 AES128 coprocessor, 1 watchdog, 1 internal voltage stabilizer and 21 programmable I/O pins which can be configured as general I/O pins. The CC2530 chip is produced by adopting a 0.18 mu mCMOS process, and the current loss is respectively lower than 27mA and 25mA in a receiving mode and a transmitting mode. The 3 sleep modes are provided, the time for switching from the sleep mode to the normal mode is extremely short, and the method is particularly suitable for application occasions requiring long-term power supply of the battery.
The CC2530 integrates a module for measuring RSSI, i.e. an RSSI weighting algorithm unit, which uses a binary 8-bit register. The value of the signal strength is an average of the power levels calculated over 8 cycles. The RF core in CC2530 may transmit at 2405MHz at the same operating frequency as the active RFID system. CC2530 may be configured experimentally as a stand-alone wireless transceiver as an active electronic tag for an RFID system as shown in fig. 2. The maximum transmission power value of the electronic tag is regulated to be 5.1dBm in the new RFID-18000 standard, so that the transmission power is configured to be 4.5 dBm.
RSSI (received Signal Strength indicator) is an indication of the Strength of the received Signal. According to the electromagnetic wave propagation theory, the uplink of the tag to the reader is considered. If the tag radiates electromagnetic waves in free space at a nominal power, the received power or field strength (power proportional to the square of field strength) at any point in the theoretical space transmitted according to Friis is only related to the distance. In an actual environment, due to the existence of random factors such as multipath, obstacles, diffraction, etc., a model commonly used in wireless signal transmission is as follows:
PL(d)＝PL(d0)+10n log10(d/d0)+X0formula (1-1)
Wherein PL (d) is the path loss after a distance d, PL (d)0) For path loss after a unit distance, d0Is a unit distance, typically 1m, X0The average value is a random number of 0 and follows Gaussian distribution, the standard deviation range is 4-10, n is a signal attenuation factor, and the range is 2-4.
The received signal strength at the receiving end is:
PR(d)＝PT+GT-PL(d) formula (1-2)
In the formula, PR(d) Is the received signal strength, i.e. RSSI, PTTo transmit the power of the signal, GTFor transmit antenna gain, based on this principle, the ieee802.15.4 standard gives a simplified signal attenuation model:
Figure RE-GDA0003030195190000051
but considering factors such as environment, cost, positioning accuracy requirement and the like, the distance measurement model in actual measurement can be further simplified into
RSSI＝-10n log10d-A type (1-4)
Wherein n is a signal attenuation factor, and is generally in the range of 2-4. d is the distance between the positioning node and the reference node; a is an RSSI value measured when the distance d between the reader and the reference label is 1m, the above formula is a classic model of RSSI ranging, and a functional relation between the RSSI and the d is obtained, so that the distance between the reader and the transmitter can be calculated by knowing the received RSSI value, A and n are empirical values and are related to specifically used hardware nodes and a wireless propagation environment, and therefore, the values of A and n are different in different actual environments. When the measurement is carried out in the actual parking lot, the obtained distance measurement model is as follows:
RSSI＝-26log10d-38 type (1-5)
Upper computer software was developed on Windows system using VB to look at the received RSSI values as shown in fig. 1.
The distances D from the tag to be detected to the three readers can be calculated by measuring the power of the electric wave from the electronic tag to the readers1、D2、D3Thus, the position of the electronic tag to be detected is respectively centered on the three readers D1、D2、D3At the intersection of circles of radii, as shown in FIG. 2;
by classical trilateration, the coordinates corresponding to the three readers are respectively (x)1，y1)，(x2，y2)，(x3， y3) The intersection point D of the three circles is the position of the label to be positioned, the coordinate is (x, y), and the distance between the corresponding measuring point and the label to be measured is D1、d2、d3According to the geometrical relationship, the following can be known:
Figure RE-GDA0003030195190000061
subtracting the first two formulas from the last formula to obtain:
Figure RE-GDA0003030195190000062
the final position coordinates are obtained by the above formula:
Figure RE-GDA0003030195190000063
as shown in fig. 3, RSSI values received by the same electronic tag on three readers and coordinate positions of the three readers are input into a system to calculate a specific position of a vehicle.
The above-described embodiments are illustrative of the present invention and not restrictive, it being understood that various changes, modifications, substitutions and alterations can be made herein without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims (8)

1. The RFID vehicle positioning system based on the RSSI algorithm is characterized by comprising a positioning device, a reader and an electronic tag, wherein the positioning device comprises an RSSI weighting algorithm unit, the RSSI weighting algorithm unit is connected with a microcontroller, and the reader comprises an antenna, a reader chip, a microcontroller and a communication interface.
2. The RSSI algorithm-based RFID vehicle positioning system of claim 1, wherein the microcontroller is a CC2530 single chip microcomputer, the CC2530 single chip microcomputer comprises a CPU, a storage unit, on-chip peripherals and an RF radio frequency unit, the on-chip peripherals mainly comprise a 5-channel 8-bit to 14-bit programmable ADC converter, a timer, a USART, a DMA controller, an AES128 co-processor, a watchdog, an internal voltage regulator and a programmable I/O pin, and the programmable I/O pin can be configured as a general purpose I/O pin.
3. The RSSI algorithm based RFID vehicle locating system of claim 2, wherein the CC2530 single chip microcomputer has a current loss lower than 27mA in a receiving mode; and in the emission mode, the current loss of the CC2530 single chip microcomputer is lower than 25 mA.
4. The RSSI-based RFID vehicle positioning system of claim 1, wherein the RSSI weighting algorithm unit uses a binary 8-bit register, the calculated value of the RSSI weighting algorithm unit is the average value of power levels calculated for 8 cycles, the RF core in the CC2530 single chip microcomputer can transmit at 2405MHz, and the electronic tag transmission power is configured to be 4.5 dBm.
5. The RSSI algorithm-based RFID vehicle positioning method of claim 4, which specifically comprises the following steps:
step one, installing a plurality of reference electronic tags and a plurality of readers in a parking lot;
step two, the electronic tag actively sends a Signal, and the reader acquires an RSSI (received Signal Strength indicator) value of the reference electronic tag;
step three, calculating a model adopted in wireless signal transmission, the signal strength received by a receiving end and the specific position of the vehicle in the system;
6. the RSSI algorithm-based RFID vehicle positioning method of claim 5, wherein the model used in the wireless signal transmission is based on the electromagnetic wave propagation theory, considering the uplink of the RFID tag and the reader, if the RFID tag radiates electromagnetic waves in free space with rated power, the received power or field strength of any point in the theoretical space is only related to the distance according to Friis, in the actual environment, due to the existence of random factors such as multipath, obstacles and diffraction, the model commonly used in the wireless signal transmission is:
PL(d)＝PL(d0)+10nlog10(d/d0)+X0formula (1-1)
Wherein PL (d) is the path loss after a distance d, PL (d)0) For path loss after a unit distance, d0Is a unit distance, typically 1m, X0The average value is a random number of 0 and follows Gaussian distribution, the standard deviation range is 4-10, n is a signal attenuation factor, and the range is 2-4.
7. The RSSI algorithm-based RFID vehicle positioning method of claim 5, wherein in step two, RSSI (received Signal Strength indicator) is an indication of the received Signal Strength, and the received Signal Strength at the receiving end is:
PR(d)＝PT+GT-PL (d) formula (1-2)
In the formula, PR(d) Is the received signal strength, i.e. RSSI, PTTo transmit the power of the signal, GTFor transmit antenna gain, based on this principle, the ieee802.15.4 standard gives a simplified signal attenuation model:
Figure RE-FDA0003030195180000021
but considering factors such as environment, cost, positioning accuracy requirement and the like, the distance measurement model in actual measurement can be further simplified into
RSSI＝-10nlog10d-A type (1-4)
In the formula, n is a signal attenuation factor, the range is generally 2-4, and d is the distance between a positioning node and a reference node; a is an RSSI value measured when the distance d between the reader and the reference tag is 1m, the above formula is a classic model of RSSI ranging, and a functional relation between the RSSI and the d is obtained, so that the distance between the reader and the transmitter can be calculated by knowing the received RSSI value, A and n are empirical values and are related to specifically used hardware nodes and a wireless propagation environment, therefore, the values of A and n are different in different actual environments, the measurement is carried out in an actual parking lot, and the obtained ranging model is as follows:
RSSI＝-26log10d-38 type (1-5)
Developing upper computer software on a Windows system by using VB, and checking a received RSSI (received Signal Strength indicator) value.
8. An RSSI algorithm based RFID vehicle positioning method of claim 5, wherein in the third step, the specific position of the vehicle is calculated in the system, and the distance D from the tag to be measured to three readers can be calculated by measuring the power of the electric wave from the electronic tag to the readers1、D2、D3Thus, the position of the electronic tag to be detected is respectively centered on the three readers D1、D2、D3At the intersection of circles of radius;
by classical trilateration, the coordinates corresponding to the three readers are respectively (x)1，y1)，(x2，y2)，(x3，y3) The intersection point D of the three circles is the position of the label to be positioned, the coordinate is (x, y), and the distance between the corresponding measuring point and the label to be measured is D1、d2、d3According to the geometrical relationship, the following can be known:
Figure RE-FDA0003030195180000031
subtracting the first two formulas from the last formula to obtain:
Figure RE-FDA0003030195180000032
the final position coordinates are obtained by the above formula:
Figure RE-FDA0003030195180000033
in the development and calculation software of Matlab on a Windows platform, RSSI values received by the same electronic tag on three readers and coordinate positions of the three readers are input into a system, so that the specific position of a vehicle can be calculated.
CN202110311014.5A 2021-03-24 2021-03-24 RFID vehicle positioning system based on RSSI algorithm and positioning method thereof Pending CN113030856A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110311014.5A CN113030856A (en) 2021-03-24 2021-03-24 RFID vehicle positioning system based on RSSI algorithm and positioning method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110311014.5A CN113030856A (en) 2021-03-24 2021-03-24 RFID vehicle positioning system based on RSSI algorithm and positioning method thereof

Publications (1)

Publication Number Publication Date
CN113030856A true CN113030856A (en) 2021-06-25

Family

ID=76473173

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110311014.5A Pending CN113030856A (en) 2021-03-24 2021-03-24 RFID vehicle positioning system based on RSSI algorithm and positioning method thereof

Country Status (1)

Country Link
CN (1) CN113030856A (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110260923A1 (en) * 2009-01-06 2011-10-27 Westvalley Digital Technologies, Inc. System and method for positioning using signal transmit power and signal receive packet error ratio
CN102928813A (en) * 2012-10-19 2013-02-13 南京大学 RSSI (Received Signal Strength Indicator) weighted centroid algorithm-based passive RFID (Radio Frequency Identification Device) label locating method
CN103279780A (en) * 2013-06-09 2013-09-04 安徽工程大学 RFID article positioning device based on RSSI weighing algorithm
CN106875733A (en) * 2017-03-17 2017-06-20 南京理工大学 Based on adaptive environment multisensor low-power consumption vehicle detecting system and method
CN108710105A (en) * 2018-06-27 2018-10-26 云南电网有限责任公司文山供电局 Localization method in Converter Station
CN109324310A (en) * 2017-08-01 2019-02-12 佛山市顺德区中山大学研究院 A kind of indoor locating system based on RFID
US20200393570A1 (en) * 2019-06-14 2020-12-17 Chicony Electronics Co., Ltd. Tracking method, electronic device using the same, and tracking system using the same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110260923A1 (en) * 2009-01-06 2011-10-27 Westvalley Digital Technologies, Inc. System and method for positioning using signal transmit power and signal receive packet error ratio
CN102928813A (en) * 2012-10-19 2013-02-13 南京大学 RSSI (Received Signal Strength Indicator) weighted centroid algorithm-based passive RFID (Radio Frequency Identification Device) label locating method
CN103279780A (en) * 2013-06-09 2013-09-04 安徽工程大学 RFID article positioning device based on RSSI weighing algorithm
CN106875733A (en) * 2017-03-17 2017-06-20 南京理工大学 Based on adaptive environment multisensor low-power consumption vehicle detecting system and method
CN109324310A (en) * 2017-08-01 2019-02-12 佛山市顺德区中山大学研究院 A kind of indoor locating system based on RFID
CN108710105A (en) * 2018-06-27 2018-10-26 云南电网有限责任公司文山供电局 Localization method in Converter Station
US20200393570A1 (en) * 2019-06-14 2020-12-17 Chicony Electronics Co., Ltd. Tracking method, electronic device using the same, and tracking system using the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
李世钊, 天津大学出版社 *

Similar Documents

Publication Publication Date Title
US9413430B2 (en) Measurement and reporting of received signal strength in NFC enabled devices
US7893876B2 (en) System and method for determining locations of medical devices
US7991354B2 (en) Method of communication and base station
KR101597199B1 (en) Rfid portal system with rfid tags having various read ranges
CN111586838B (en) Underground accurate positioning method for coal mine
EP3836096A1 (en) Smart lock and smart monitoring
CN101553029B (en) Positioning method and positioning device of signal intensity rate in wireless sensor network
CN109212474B (en) Underground positioning method based on EIEL electronic tag
CN101320092A (en) Positioning method based on wireless radio frequency recognition technology
CN110956424B (en) Inventory tracking tags, systems and methods for extending battery life
CN102184436A (en) Method for sensing position of object in Internet of things
CN111186320A (en) Wireless charging guiding and positioning system and method and vehicle-mounted equipment
CN101110735A (en) Industrial production workshop security positioning system and method based on wireless sensor network
KR20190073252A (en) Container locating system, method and electronic tag
CN103487676A (en) Method and device used for testing performance of RFID electronic tag
D'Aloia et al. Improving energy efficiency in building system using a novel people localization system
CN103680192B (en) A kind of vehicle and parking stall accurate recognition system
WO2021192421A1 (en) Communication unit, communication device, and position estimating method
KR20110067708A (en) System and method for measuring a rfid field environment
CN113030856A (en) RFID vehicle positioning system based on RSSI algorithm and positioning method thereof
CN102395897B (en) Area identification and area definition by utilizing rf technology
KR102277798B1 (en) Construction equipment access detection system using dual AP and beacon coverage and method Thereof
CN104391269A (en) Spatial orientation method and apparatus based on radio frequency identification technology
EP4109931A1 (en) Improving battery life during bluetooth device localization
CN103796165B (en) Determine the probabilistic method of down-hole personnel position

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20210625