Track and trace

The impressive list of benefits offered by a real-time location system (RTLS) to factory and warehouse managers makes its specification something of a no-brainer. 

From turbocharging productivity and reducing accidents to eliminating lost stock and accelerating stock picking, a RTLS can have a huge impact on how smoothly a business operates by detecting and recording, in real time, the geographical location of assets typically found in warehouses and factories. 

There are several types of RTLS, each using different detecting technologies and the one (or mix) you select for your operation will depend largely on the accuracy you require. 

However, one thing all RTLS have in common is that they reveal, from moment to moment, the location of stock, material handling equipment (MHE) and people. By minimising the interaction with people, an RTLS also reduces the possibility of human error entering the process. 

The benefits of selecting the right RTLS include:

* Informing you of the exact real-time location of every pallet, pedestrian and piece of MHE in your warehouse – speeding up stock picking and boosting safety by reducing the possibility of collisions.

* Reducing manual processes – preventing costly and time-wasting human error.

* Increasing inventory accuracy – preventing mis-picks and reducing lost inventory.

* Cutting the time taken to record stock transactions and the time wasted looking for inventory – improving handling efficiency, raising the number of possible moves per hour and limiting expensive losses.

* Improving staff behaviour – helping people perform their duties more effectively and boosting morale.

The three main types of technology used with RTLS are radio frequency identification (RFID), Wi-Fi and optical tracking (see the box). 

The lowest resolution technology is passive RFID which uses low cost tags, which are scanned automatically as they pass through a ‘pinch point’, portal or other confined, defined space in the warehouse such as a dock door. This means that the system knows the items to which the tag is attached have passed through certain points.

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However, passive RFID systems only allow you to detect and track an item by room, or part of the warehouse or factory. 

The next resolution level up is active RFID, where each tag constantly emits its details, although the basic level of this system still lacks precise positional accuracy. 

The third resolution level is to provide positioning with an active tag using Wi-Fi rather than RFID as the communication medium.  

There are two types of Wi-Fi based system. Non-proprietary ‘open’ systems use a standard Wi-Fi infrastructure employing normal access points, but their accuracy is limited.

The alternative is a proprietary product or system owned exclusively by a single company. Vero’s patented Wi-Fi technology, for example, is specifically designed to deliver an effective method of pedestrian and forklift tracking, both indoors and outdoors. The Vero Wi-Fi offers sub-metre accuracy of each tagged element and can be installed at relatively low cost. 

The most accurate indoor tracking comes with optical systems, usually attached to a forklift truck. Typically, a top-mounted camera takes multiple images each second of overhead location markers to calculate the real-time location of each forklift truck as well as its direction and speed. 

A front-mounted camera reads the pallet’s identification label and tracks its movement throughout the warehouse to its precise pick-up or put-away location. 

So, RTLS systems come in many shapes and sizes with various features and functions. The system or systems most appropriate for your site will depend on a range of factors such as how big your facility is, what it’s storing and how quickly you need to retrieve inventory.