Mobile autonomous device for tracking the number of vehicles using RFID tags in the field

Abstract

This utility model pertains to information technology. The technical result consists of ensuring autonomous operation of the device without external power for at least 30 days. This is achieved by a mobile autonomous device for tracking the number of vehicles using RFID tags in the field. The device comprises a sealed, impact-resistant housing, a UHF RFID module, an antenna, a battery with a capacity of at least 10 Ah, non-volatile memory, a real-time clock, and a microcontroller. 2 fig.

Description

[0001] The utility model relates to radio frequency identification (RFID) technology and can be used for automated counting of passing vehicles equipped with RFID transponders in places without stationary power supply, communication and access to computer infrastructure: forest roads, checkpoints on highways, construction sites, quarries, temporary crossings.

[0002] Various vehicle identification systems using radio frequency identification are known from the prior art.

[0003] A "Vehicle Identification and / or Monitoring System" is known under patent RU 2016138614 A [1], comprising an RFID reader with an antenna designed for installation on or in the road surface, wherein the antenna forms a radiation pattern in the form of a wide and low elliptical torus above the road surface. The reader provides a reading range of up to 6-10 meters.

[0004] Disadvantages of the analog: the device is stationary, requires connection to an external power source, and is not suitable for field operation without a power grid. Furthermore, the system is designed to work with tags installed on license plates and does not include algorithms to prevent the same tag from being read twice when the vehicle is stopped.

[0005] The "Passive Safety and Vehicle Tracking System Using Permanent and Variable Smart Tags" is known under patent for utility model RU 91091 U1 [2], comprising a vehicle code reader, a permanent code memory unit, and a data processing unit. The system enables vehicle identification using permanent and variable smart tags.

[0006] Disadvantages of the analog: the device is stationary, designed to work with a connection to a central information processing server, does not have an autonomous power supply and is not intended for use in field conditions in the absence of external infrastructure.

[0007] A “Device for the simultaneous reading of identifiers from a group of near-field radio frequency tags” is known from patent RU 2475841 C1 [3], containing a metal housing with an internal cavity for placing marked products and an antenna placed inside the housing for reading the tags.

[0008] Disadvantages of the analog: the device is designed for inventorying items within a closed space (for tracking jewelry and goods), but is not suitable for tracking moving vehicles. There is no ability to record travel time or link to a geolocation. The device is not mobile or autonomous enough for field use.

[0009] The closest analogue (prototype) was chosen to be the "Intelligent Entry / Exit System with Automatic Unmanned Weighing" (Patent CN 103576648 B, China) [4], which is closest to the claimed utility model in technical essence and purpose. The known system comprises an RFID module for identifying radio frequency cards installed on vehicles, a license plate recognition unit, a video monitoring module, an information display, a voice interaction module, and a main control system. The system provides automatic identification of a vehicle by an RFID tag upon entering the weighing platform and records the number of passing vehicles.

[0010] A disadvantage of the prototype is that it is a stationary system requiring a 220V power supply and a wired communications infrastructure. This makes it unsuitable for use in field conditions (forest roads, construction sites, quarries, temporary crossings) without external power. Constant operation of the RFID module and control system in active mode leads to rapid battery drain, precluding the possibility of long-term autonomous operation (more than a few hours).

[0011] Under field conditions (no power supply, remoteness, long-term operation), known RFID devices are not capable of operating autonomously for more than a few hours or a day due to the high power consumption of the RFID module (up to 30-35 mA in active mode) and the lack of a deep power saving mode.

[0012] The technical problem that the claimed utility model is aimed at solving is to ensure long-term (at least 30 days) autonomous operation of a device for recording vehicles using RFID tags in field conditions in the absence of external power supply.

[0013] The technical result of the claimed utility model is to ensure autonomous operation of the device without external power supply for at least 30 days.

[0014] The essence of the utility model is that the mobile autonomous device for recording the number of vehicles using RFID tags in field conditions contains:

[0015] 1) sealed shockproof housing (1) (protection class not lower than IP65), inside which are located:

[0016] microcontroller (2) with a clock frequency of no more than 32 MHz;

[0017] UHF RFID module (3) (860-960 MHz range) with an output power of no more than 10 dBm and the ability to switch to power saving mode;

[0018] antenna (4), designed with the possibility of installation on the body or remotely on a cable;

[0019] power element (5) (rechargeable battery or set of replaceable galvanic elements) with charge controller and deep discharge protection;

[0020] non-volatile memory (6) for storing accounting events;

[0021] Real time clock (7) with separate backup power supply;

[0022] GPS / GLONASS module (8);

[0023] BLE / Wi-Fi module (9).

[0024] 2) wherein the microcontroller (2) is configured to cyclically switch to the ultra-low power consumption mode (“deep sleep”) with a consumption of no more than 20 μA and short-term awakening for polling the RFID ether at a specified interval from 100 to 500 ms.

[0025] Distinctive features of the utility model:

[0026] The microcontroller (2) is designed with the ability to operate in a cyclic “deep sleep” - “active polling” mode, in which the duration of the active phase is no more than 10-50 ms for each cycle, and the interval between cycles is set from 100 to 500 ms, which ensures an average power consumption of no more than 0.5 mA;

[0027] The RFID module (3) is designed with the ability to completely turn off the power in the microcontroller’s deep sleep mode and turn on only during the active polling phase;

[0028] A rechargeable battery with a capacity of at least 10 Ah or a set of replaceable 18650 type elements with a total capacity of at least 10 Ah is used as the power element (5).

[0029] The claimed utility model allows achieving the specified technical result due to the fact that:

[0030] cyclic operating mode with a long “sleep” (up to 500 ms) and a short-term active phase (less than 50 ms) provides an average power consumption of 0.2-0.5 mA;

[0031] Disabling the RFID module in sleep mode eliminates parasitic power consumption of this unit, which in active mode can reach 30-35 mA;

[0032] Using a power source with a capacity of at least 10Ah (18650 battery or 18650 battery pack) provides the necessary energy reserve.

[0033] Calculation: 10 Ah / 0.0005 A = 20,000 hours ≈ 833 days theoretically. Taking into account low temperatures (down to -30°C), battery self-discharge, and capacity loss during operation, the actual battery life is at least 30-60 days.

[0034] List of figures:

[0035] Fig. 1 - functional electrical diagram of the device;

[0036] Fig. 2 - external appearance of the device (housing with arrangement of elements).

[0037] The device is housed in a sealed, impact-resistant enclosure (1) with a protection rating of at least IP65, ensuring its operation in conditions of high humidity, dust, and precipitation. All the main electronic components are housed inside the enclosure.

[0038] Operating mode.

[0039] The microcontroller (2) implements an energy-efficient cyclic algorithm:

[0040] 1. Deep sleep mode - the microcontroller and all peripheral modules (including the RFID module (3) and GPS / GLONASS module (8)) are in an ultra-low power state (less than 20 μA). The RFID module is completely powered off.

[0041] 2. Wake-up - after a specified interval (100-500 ms) the built-in timer of the microcontroller initiates wake-up.

[0042] 3. Active phase (10-50 ms) - the microcontroller turns on the power of the RFID module (3), which performs a one-time inventory of RFID tags in the coverage area.

[0043] 4. Result processing - when a tag is detected, its EPC code is checked in the active tag buffer (preventing double counting). If the code is not found in the buffer, a passage event is recorded and saved to non-volatile memory (6).

[0044] 5. Enter sleep mode - the microcontroller turns off the power to the RFID module and repeats the cycle.

[0045] To prevent multiple readings of a single vehicle (e.g., when stopped or driving slowly), a buffer of active tags in RAM is used. The EPC code of a detected tag is stored in the buffer for a specified time (e.g., 30 seconds). Repeated readings of the same tag during this time are ignored.

[0046] The device operates as follows.

[0047] Before operation, the operator installs the device at a vehicle registration point (a pole, tree, or support at a height of 2-3 meters). The antenna (4) is directed toward the vehicle access area. Power is turned on using the toggle switch (Fig. 2, pos. 10) on the housing.

[0048] After power-on, the microcontroller (2) initializes the RFID module (3), real-time clock (7) and enters the main working cycle:

[0049] 1. The microcontroller (2) puts itself and all peripheral modules (RFID module (3), GPS / GLONASS module (8)) into deep sleep mode with a consumption of no more than 20 μA.

[0050] 2. After a specified interval (for example, 200 ms), the microcontroller (2) wakes up by a signal from the built-in timer.

[0051] 3. The microcontroller (2) powers up the RFID module (3), which performs a one-time inventory of RFID tags within the coverage area. The active phase duration is 10-50 ms.

[0052] 4. If an RFID tag is detected, the microcontroller (2) checks if its EPC code is in the active tag buffer stored in the RAM:

[0053] If the code is absent, the fact of vehicle passage is recorded: the tag code, the timestamp from the real-time clock and the signal level are saved in non-volatile memory (6); the vehicle counter is increased by 1; the tag code is placed in the active tag buffer for a specified time (e.g. 30 seconds);

[0054] If the code is present in the buffer, the label is ignored (avoiding re-counting).

[0055] 5. The microcontroller (2) turns off the power of the RFID module (3) and enters deep sleep mode.

[0056] The cycles are repeated continuously.

[0057] To download accumulated data, the operator connects to the device via the USB port (Fig. 2, pos. 11) or Bluetooth Low Energy (if the appropriate module is available). Data is downloaded in CSV / JSON format.

[0058] Specific implementation example:

[0059] microcontroller: STM32L053 (consumption in Stop mode - 5 μA);

[0060] RFID module: M6E-NANO with output power of 10dBm;

[0061] Power supply: 4 18650 elements with a total capacity of 10 Ah via an LDO regulator with an efficiency of> 90%;

[0062] Polling interval: 200ms;

[0063] active phase duration: 10ms;

[0064] Average current: ≈0.2mA.

[0065] Estimated autonomy: 10 A⋅h / 0.0002 A = 50,000 hours ≈ 5.7 years (theoretically), taking into account low temperatures and self-discharge - at least 60 days of continuous operation.

[0066] The utility model can be repeatedly reproduced and used in accordance with its intended purpose.

[0067] The device can be manufactured industrially using standard electronic components (STM32, ESP32, or similar microcontrollers; Impinj R2000, M6E-NANO, or similar RFID modules; 18650 batteries) and a standard IP65 enclosure. The widespread availability of these components and the proven circuit design confirm the feasibility of mass production.

[0068] Suggested scope of use: Ministry of Defense, road services, logistics companies, construction organizations, civil defense units.

[0069] Links to information sources:

[0070] 1. Patent application RU 2016138614 A, IPC: G08G 1 / 017. Vehicle identification and / or monitoring system.

[0071] 2. Utility Model Patent RU 91091 U1, IPC: G08G 1 / 00 ​​(2006.01). Passive safety and vehicle tracking system using permanent and variable smart tags.

[0072] 3. Patent RU 2475841 C1, IPC: G06K 7 / 08, G06K 19 / 07. Device for simultaneous reading of identifiers from a group of near-field radio frequency tags.

[0073] 4. Invention Patent CN 103576648 B, IPC: G01G 19 / 02. Intelligent entry / exit system with automatic unmanned weighing (prototype).

Claims

A mobile autonomous device for recording the number of vehicles using RFID tags in field conditions, comprising a sealed housing with a UHF RFID module, antenna, non-volatile memory and a real-time clock placed therein, characterized in that it is equipped with a microcontroller and a power element in the form of a rechargeable battery with a capacity of at least 10 A⋅h, wherein the microcontroller is configured to cyclically switch to a power consumption mode of no more than 20 μA and to briefly wake up to turn on the power of the RFID module with an interval of 100 to 500 ms, the duration of the active phase of polling the tags is from 10 to 50 ms, and the average power consumption of the device is no more than 0.5 mA.

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