Systems for identifying and tracking the position of objects
The term ‚location‘ refers to the automatic acquisition of the position of moving objects by means of indoor positioning systems, also known as Real-time Location Systems (RTLS) or by satellite positioning in outdoor areas using GPS, Galileo, etc.
Location systems enable the automatic, continuous and complete identification and tracking of objects in real time, comparable to a video recording. Events such as an entry into defined areas from all directions or even the collision of two different objects can be detected in the digital model in real time. For example the automatic recording of transportation between plants, material flow in logistics and production, the use of tools and assets.
Location systems are based on various technologies with different characteristics and costs. In outdoor areas, external infrastructure such as satellite networks or data communication networks can usually be used. The accuracies that can be achieved with standard antennas are limited to a maximum resolution of 10 meters. With suitable, special antennas and a higher energy consumption, the resolution of GPS/Galileo can be improved to up to one meter. 5G networks promise better accuracy in the future. But it remains to be seen how much additional infrastructure will be necessary. For indoor tracking, a dedicated infrastructure is definitely required. The spectrum of possibilities ranges from the detection of presence in a building, simple zone location, precise location with a resolution of about one meter to high-precision location with resolutions of a few centimeters or even millimeters. A simple rule of thumb is: the more precise the resolution of the location, the more investment is necessary to implement the system.
This graph shows the relationship between increasing accuracy (vertical axis) and the cost of a reference configuration for the various location technologies. There is no technology that represents an ideal solution. Rather, our guideline is to select the appropriate technology for an use case respecting the goal of a return on the investment. Therefore it is important that different technologies can be combined in one application software environment to cover all use cases with one user interface and as little integration effort as possible.
|Methodology||Detect entry and exit via gateway/chokepoint or manual scanning||Strongest RSSI at one or more receivers||Weighted RSSI, Triangulation, Multilateration||Triangulation, Multilateration|
|Reliability||Missing an entry or exit results in a permanent error or is due to human error||Positive interference of the signal (false positive) results temporarily in an incorrect selection||Location error leads temporarily to an incorrect position||Location error leads temporarily to an incorrect position|
|Mitigation||Manual plausibility check defined by the process step||Manual or automatic plausibility check made by software||Automatic plausibility check made by software / due to geometry||Automatic plausibility check made by software / due to geometry|
|Requirement||Defined entry/exit gates||Signals separated by physical barriers (e.g. by a wall)||Buffer zones between areas (e.g. aisle)||Minimum required tolerance compatible with the accuracy|
(1 gateway per access)
(1 or more receivers, depending on the size of the room)
|Suitability||Registration of incoming goods, logistics, issuing tools, etc.||Block storage, tool storage, mustering (counting objects in the vicinity), etc.||Tracking work in progress, finding objects (also in open spaces)||Automation, e.g. registering a storage location, plausibility check, equipment configuration or actuation, etc.|
It is very challenging to keep track of the different technologies and vendors in the field of location and identification systems. Development is taking place in ever faster cycles. We know the advantages and disadvantages of the most important systems on the market and keep a close eye on further developments.