28 June 2019

The 3Ps of Location: Presence, Proximity & Positioning

Real-Time Location Systems (RTLS) can provide real value for companies. However, selecting the right RTLS solution for your needs requires a little bit of work. The market offers a variety of technology solutions offering different features and at a range of price points. At the same time, different use cases have different performance requirements for RTLS solutions. So, in order to identify the right solution for you, you should get to know what we at Quuppa like to call the three Ps of location (3Ps): presence, proximity and positioning.

For us, the 3Ps are basically three levels of location accuracy. Presence is the least accurate, positioning is the most accurate and proximity is somewhere in between. Quuppa technology can be used for all of these levels of accuracy (see figure 1).

Figure 1. Quuppa technology offers a solution that can span the whole range of accuracy requirements from presence detection to positioning. Note: this image is not to scale.

Presence

Presence detection is the simplest and least accurate location-based solution. The aim is to identify whether an item is present or not.

Let’s take a warehouse as an example. Typically, radio devices are used to form a gate to identify if a tracked pallet has arrived at the warehouse. Quuppa’s solution is to place a Quuppa Locator (or multiple if needed) at the entrance of the warehouse to act as a gate and to tag items that need to be tracked with Bluetooth™ tags. As the tracked item moves through the gate, the Locator identifies the tag based on its unique ID and measures the Angle-of-Arrival (AoA) of the tag’s signal. Based on the measurements, the Quuppa system can then calculate the direction of motion for the item, so whether it is entering or exiting the warehouse.

Additionally, Quuppa’s technology can also be used for presence detection once the item is inside the warehouse. The Locator’s long communication range (for more on range see Bluetooth for RTLS: Coverage Vs Range) means that the Quuppa system can continue receiving the radio packets transmitted by active Bluetooth™ tags after they have passed the gate, providing real-time information that they are still present in the warehouse. Note that for installations meant only for presence detection, the Locators can also be mounted onto the walls (they are typically mounted onto the ceiling). Standard Quuppa Approved tags also include acceleration sensors that provide real-time status reports about whether the tag is in motion or stationary. This feature is particularly useful for preventing human errors in warehouses as alerts can be triggered if items are reported in motion ahead of schedule.

Figure 2. Presence detection is used to identify whether an item is present in the area or not. The location of the item within the area cannot be identified using presence detection. Note: this image is not to scale.

RFID technology is also often used for presence detection. Even though RFID technology can be a good solution for detecting if products have arrived at their destination, the technology has some limitations. For example, a single standard reader cannot calculate the direction of motion of tracked items and so multiple reader gates are needed to know if items are entering or exiting the warehouse, raising infrastructure costs. Also, RFID technology does not provide automatic detection of an item that has already passed the gate, so there is no way to know if the item is still present in the warehouse. The Quuppa solution is a cost-effective alternative that provides a more diverse portfolio of use case solutions.

Positioning

Positioning is the highest level of location accuracy. The aim is to reliably identify the exact location of the tracked item through consistent and real-time tracking. This level of accuracy unlocks the full potential of location-based solutions.

Let’s return again to our warehouse example: in many cases, it is critical to know the precise and real-time location of items within the warehouse. For example, solutions for inventory management, worker safety, collision avoidance, Automatic Guided Vehicle (AGV) guidance and advanced workflow optimization all require precise location information. Quuppa’s solution is to make sure that the whole area of interest is uniformly covered by the Locators, so that the system can reliably calculate the accurate location of tags with minimal delays. Investing into the high-accuracy positioning infrastructure opens the door to a whole host of new potential use cases. At the same time, with Quuppa’s technology, all of the presence and proximity scenarios are also supported by the same system.

Figure 3. Positioning solutions provide accurate location information for items in a given area. Note: this image is not to scale.

Ultra-wideband (UWB) has become a popular technology for cases needing this high level of location accuracy. However, we should remember that UWB cannot be adapted in the deployment environment to cover both proximity and positioning requirements. UWB solutions are effectively either on or off, while Quuppa’s solution can always be adjusted to the current needs of the project. The high cost of tags and the limits to radio certifications across different geographical areas also limit the usability of UWB technology for positioning solutions.

Proximity

In the context of location, proximity is somewhere between the above described presence and positioning scenarios. The aim is to identify both the presence and location of items. Proximity solutions typically use a combination of high-accuracy positioning in key areas and low-accuracy presence detection in other areas. For this reason, proximity solutions are ideal for use cases where the end customer does not need uniformly accurate coverage throughout the deployment area.

Returning once more to the warehouse example, we can see that the lack of accuracy limits the use cases of presence detection while high-accuracy positioning is unnecessary in some cases. For example, approximate location information may be good enough for basic workflow optimization. This is where proximity solutions become useful. Quuppa’s solution is to place Locators in strategic areas within the warehouse, for example at the crossings between aisles or at specific choke points. This way the Locators identify tracked items as they enter certain areas within the warehouse, generating real-time location information by zone. In a well-designed deployment, where Locators are positioned at strategic choke points, the basic level of movement tracking also becomes available. Being able to optimize the infrastructure deployment and Locator density to enable the higher location accuracy only where needed provides a great advantage when optimizing the project budget, without having to compromise on the on the larger range of potential use cases.

Figure 4. Proximity solutions identify the presence and location of items in an area. Note: this image is not to scale.

Other technologies typically used to get proximity level location accuracy are Wi-Fi and Bluetooth™ Received Signal Strength Indication (RSSI) -based beaconing. Different technologies have their merits but Quuppa-based solutions are typically more flexible and robust, for example, allowing for deployments with a non-uniform locator density for optimizing the accuracy across the different zones. Quuppa provides high accuracy tracking in the choke points, uses economical low-power tag devices (compared to Wi-Fi) in the solutions, and requires significantly lower maintenance therefore lowering the total cost of ownership (TCO). In addition, it is easily adjustable to include both presence or positioning solutions using the same technology platform.

Conclusion

As we can see, different use cases have different requirements for the level of accuracy and call for different types of system architectures. What Quuppa offers with the Quuppa Intelligent Locating System™ is a solution that has all of the different levels of location accuracy. It scales together with your business: all you need to do is add some new Locators to your current infrastructure to upgrade your system from proximity-level accuracy to positioning-level accuracy. With Quuppa there is no need to start all over with new technology if your needs change and more use cases need to be supported by the same platform. Finding the right trade-off between infrastructure requirements, costs and benefits is directly in the hands of the solution provider. One of Quuppa’s key strengths is providing one technology that works for a multitude of use cases.

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