This post was last updated on September 8th, 2021 at 03:50 pm
RFID is a cost-effective way to track assets and improve efficiency but systems need to be consistent and reliable if users are to have confidence in the data.
CoreRFID offers an independent audit and consultancy service to help companies resolve any problems with existing systems. This case involved an RFID vehicle tracking system at a goods depot which was failing to detect some of the vehicles arriving. CoreRFID was able to identify a number of problems with the system and show the company how to resolve them.
Identifying the issues
Where problems do arise with RFID systems, often it is not the technology at fault but the fact that different components are not set up in an optimal way or working together properly.
Is the right combination of tags and readers being used? Is the software operating correctly with the devices? Is the hardware set up in the optimal fashion? With so many different variables in a system, diagnosis can require a great deal of skill.
In this case, the RFID system was designed to detect vehicles entering or leaving the loading bays of the depot. Each van had two identical UHF RFID tags mounted on either side of the driver’s cab – the idea being that the tags would be detected by UHF RFID readers installed in the inbound and outbound lanes.
However an audit showed that while the system was achieving a 99.5% success rate in the outbound lane, the success rate in the inbound lane was just 70% to 80%.
So what had gone wrong?
The initial examination revealed a number of issues contributing to the poor performance:
- Instead of having the same tag on each side of the cab, some vans had different versions of the tags with different performance characteristics.
- Tags were not always mounted in the same place on each van, which meant that the antennas were not always in the best position, and in some cases tags were fitted next to metal framing that could cause interference.
- Some tags were also the wrong frequency (FCC rather than ETSI compatible) and in one case a tag had no active RFID inlay!
The CoreRFID team measured performance in the existing format and then with a possible revised configuration. Tests carried out on 36 different vehicles revealed that of these, three had tags that failed to read at all due to incorrect mounting, while five others had readability index values close to the limit of acceptable performance.
Tests using different reader / antenna configurations showed that the best results were achieved by reconfiguring the antenna and reader to so-called bi-static mode. This improved performance by over 10% to a level that would allow successful operation.
7 tips to improve the success of logistics systems
CoreRFID’s report included the following recommendations, which represent good practice for RFID logistics systems in general:
- Check all tags in use to ensure they are, in fact, operational.
- Carry out an audit of the full vehicle fleet to check tag positioning.
- Overcome the differences in performance between old and new tag models, for example by replacing both tags on a van at the same time.
- Configure reader channels so they are compatible with the rest of the system.
- Avoid any applications likely to cause performance problems, such as an alarm system that might interfere with RFID signals.
- Provide guidelines on the positioning of RFID readers – for example if they can be moved around, ensure the correct position is known so they can be put back in place.
- Ensure new or replacement tags are of a frequency that is compatible with readers.