Yes, it’s possible to track RFID tags as long as the readers are compatible with the RFID system being used. Unlike GPS, standard RFID doesn’t provide real-time location tracking. The information collected by the RFID system is limited to where and when the RFID tags were detected. This can help reduce losses, errors, and shipping mistakes.
This guide covers RFID tracking, influencing factors, and how to choose the optimal setup.
What Does “RFID Tracking” Actually Mean?
An RFID system may not track a live location; it may simply be used to trace a product, confirm if it’s entering or leaving an area, and indicate its last known position.
For instance, an RFID gateway in a warehouse can track a pallet leaving Dock 3 at 3:00 p.m. An RFID reader in the repair department can confirm that the same tool is still there.
How Does RFID Tracking Work?
RFID tracking begins with an RFID tag ID number associated with an item record. The item is placed within the field of an RFID antenna that emits a radio signal.
A reader records the tag number, capture time, and antenna location. The middleware filters out duplicates, and the software generates an event such as “Box 123 entered Packing Room 2 at 11:48 a.m.”
Tags usually carry only an ID number and a small amount of data. Your WMS, ERP, MES, EAM, asset management system, or cloud storage system contains the complete tracking record.
Can Passive RFID Tags Be Tracked?
Yes. Passive RFID tags can be tracked when they are within range of an appropriate reader. The tag doesn’t have a battery. Instead, the chip powers itself using the reader’s radio waves and sends back the tag’s ID.
Its small size and low cost make it good for clothing, boxes, pallets, tools, and IT equipment. Fixed readers detect the presence of tags at doors and workstations, and portable readers are used for inventory checks and searches.
Can Active RFID Tags Be Tracked?
Active RFID tags contain a battery and transmitter, enabling wider coverage and more frequent updates than passive RFID tags. Hospitals use them to locate portable equipment, and manufacturing facilities use them to track vehicles, containers, and expensive tools.
Tags with sensors may also detect motion, collisions, temperature changes, or humidity changes. However, active RFID still requires receivers and location-based software and can’t provide global GPS tracking. The project budget must also account for more expensive tags and battery replacement.
Passive vs. Active RFID Tracking
| Factor | Passive RFID | Active RFID |
| Power Source | Reader-powered | Battery-powered |
| Use For | Products, pallets, tools | Vehicles, people, valuable assets |
| Location
| Last seen at a checkpoint or within a zone | Broader zone tracking with periodic updates |
| Range | Within a few meters | More than tens of meters |
| Cost | Low | High |
| Maintenance | Minimal | Battery maintenance required |
Use passive RFID for large numbers of items. Use active RFID if each item justifies general coverage and periodic updates.
How Far Can RFID Tags Be Tracked?
The distance over which RFID works depends on the technology’s frequency. LF technology works only at close range, while HF/NFC might work at distances of up to one meter, passive UHF at distances of up to a few meters, and active RFID at distances of tens of meters.
However, these distances aren’t absolute, as many factors determine the range of the technology, like the reader power and the type and size of the antenna used. Liquid-filled and metallic items require specific RFID tag positioning.
Can RFID Provide an Exact Real-Time Location?
Basic RFID indicates the checkpoint, room, area, or last known location but doesn’t provide an exact point on a map. A portal may read 99 out of 100 cartons, but it can only determine that they crossed the entry point.
What RFID Tracking Methods Are Available?
Fixed RFID Portals
Readers at doors, loading docks, gates, or workstations capture the movement of items. A shipping portal can check if any cartons are missing by comparing the RFID-tagged cartons with the order.
Zone-Based Tracking
Readers monitor rooms or work cells. Software displays the current or last known zone. Select this method if you only need room-level visibility.
Handheld RFID Search
A worker selects the tag to search for and follows signal bars or audio cues. The device helps narrow the search but can’t determine the distance to the tag.
Smart Shelves and Cabinets
Built-in antennas detect what is in place, removed, moved, or in need of replenishment. Tool rooms and medical cabinets use such configurations.
Overhead RFID Readers
These ceiling-mounted readers cover a larger area. Some models may use multiple antennas, signal phase, or directional data to estimate location.
Active RFID RTLS
Active RFID tags transmit data to on-site receivers. Software estimates the location using signal strength, angle, time, or combined data.
Hybrid RFID and GPS/UWB/BLE
RFID tags identify the item. GPS tracks vehicle movement outdoors. UWB determines indoor location. Bluetooth detects zones or rooms.
What Equipment Is Needed to Track RFID Tags?
Monitoring RFID tags requires tags, readers, antennas, middleware, software, and connectivity. While fixed readers are responsible for monitoring access through doors or workstations, handheld readers handle stock counting and searching. The antennas define each read area.
Both the tags and readers must operate at the same frequency and follow the same protocol. Typically, passive UHF systems use RAIN RFID, EPC Gen2, or ISO/IEC 18000-63 protocols. Furthermore, it’s essential that the tags are designed according to the characteristics of the asset, such as on-metal, heat-resistant, or sealed tags.
What Can Be Tracked with RFID?
Warehouse and Logistics
RFID can track cartons, pallets, reusable containers, baggage, and transport items during receiving, storage, picking, loading, and shipping.
Manufacturing
RFID labeling of raw materials, work-in-progress items, tools, molds, fixtures, and repairable items is carried out in factories. Station identification provides information about where an item was last stored or where a tool was last used.
Retail
RFID inventory tracking includes apparel, footwear, jewelry, consumer electronics, cosmetics, and returns without requiring every barcode to be scanned.
Healthcare
RFID tracking is used for beds, wheelchairs, pumps, surgical instruments, samples, drugs, and employee IDs. An RFID system must be planned with cleanability, mounting, privacy, and access control in mind.
IT and Fixed Assets
RFID asset tracking includes laptops, servers, printers, hard drives, networking devices, and office equipment. A handheld device is used for auditing, searching for, lending, and transferring assets.
RFID vs. GPS vs. Bluetooth vs. UWB
| Technology | For | Location information |
| Passive RFID | Large items and portals | Checkpoint or zone |
| Active RFID | Valuable indoor items | Regular location updates |
| GPS | Outdoor items and vehicles | Global coordinates |
| Bluetooth | Rooms, people, and devices | Approximate zone |
| UWB | Indoor tracking | Precise coordinates |
| NFC | Smartphone taps | Proximity detection |
Use RFID for identification and tracking, GPS for outdoor tracking, Bluetooth for zone detection, and UWB for precise indoor tracking.
What Affects RFID Tracking Performance?
RFID signals are reflected by metal and absorbed by liquids. In dense stacks, inner tags may be blocked. Factors that influence reading include tag size, antenna design, positioning, and orientation.
Reader power, antenna direction, item speed, wall placement, and signal reflections influence the read area. The setup must be tested with actual items under normal working requirements.
What Are the Limitations of RFID Tracking?
The location is updated by the RFID tracking system only when the tag is scanned by a compatible reader. Once the tag moves out of the reader’s range, only its last known position is recorded.
Additionally, the reader and tag must use the same frequency and protocol. Smartphones usually cannot scan passive UHF tags. Precise location tracking requires additional scanning equipment.
Can RFID Tags Be Used to Track People?
Yes, but only in a well-planned RFID tracking environment. A person must have an identifiable tag, compatible readers must be installed in the area, and the tag ID must be linked to the individual.
Passive tags stop registering new locations once they are out of range of the readers. The main privacy concern is linking a unique ID to personal information and stored location data. Indirect identifiers, restricted access, collection of only necessary records, and timely deletion are important.
How Do You Choose the Right RFID Tracking Solution?
Choose the RFID tracking system according to its purpose: inventory, entry and exit tracking, room tracking, or precise location tracking. Select tags, readers, and software that fits the object’s material, size, position, speed, environment, privacy restrictions, quantity, and budget.
Test with the actual object, tag position, object speed, and software interface. Measure the read rate, missed reads, cross-zone reads, response time, and accuracy.
Frequently Asked Questions
Can passive RFID tags be tracked?
Yes. A compatible reader will detect the passive RFID tag when it enters the read area. After it leaves, the system indicates where and when it was last seen.
Do RFID tags have GPS?
Standard RFID tags don’t have GPS. They transmit data when they are detected by a nearby compatible reader. Some tracking devices include separate RFID and GPS modules.
Can RFID tags be tracked anywhere?
No. RFID works only in areas where readers are installed. To track an object across a city or country, use GPS, cellular networks, or similar technologies.
Can a smartphone track an RFID tag?
Most modern phones can detect an NFC tag. Passive UHF tags need an external reader.
Can RFID tags be tracked through walls?
RFID signals might penetrate some non-metallic surfaces. Walls, metal objects, distance, and other factors may interfere with the signal and make it inconsistent.
Can RFID show an exact location?
Basic RFID technology shows checkpoints, rooms, zones, last known locations, and other data. For precise coordinates, use real-time location systems, including UWB and active RFID.
How long can an RFID tag be tracked?
Passive tags can be tracked as long as they remain operational, attached to the item, and within range of a reader. The same applies to active RFID tags.
Can RFID tags be reused?
Hard tags, pallet tags, washable tags, and rewritable tags can be reused. Adhesive labels are harder to reuse because removing them can damage the label.
Can someone secretly track you with RFID?
If there’s a compatible reader nearby, it can read the RFID tag. Passive RFID doesn’t track remotely like GPS, but linking a tag ID to personal data increases the privacy risks.
Does an RFID tag store its location history?
Not usually. Reader locations, movement records, and read times are stored in the back-end system.
Conclusion
RFID can be used to track inventory, entry, zones, handheld reads, or even positioning. Depending on how specific you want the information to be, you may use passive RFID, active RFID, GPS, Bluetooth, UWB, or a combination of technologies.
Once you’ve determined the type of item you’re going to track, its physical characteristics, and the required quantity, it’s time to test different technologies. JLTRFID can help you choose the right tag and test different readers.
