The most pervasive example of an RTLS is GPS. The problems begin when you go indoors however. GPS doesn't work indoors so all the tracking and location functionality that GPS provides suddenly disappears. But long before the advent of GPS people across a broad range of industries were examining their business processes and they began to realize that with accurate location information they could, in many cases, transform those businesses or at the very least make considerable improvements in costs, service and profits. Since then people have been searching for reliable, accurate location technology that could be applied to their business process. For a technology review also check ETH zurich independant report: Indoor positioning technologies
The advent of cost-effective wireless technology has led to many attempts to apply it to RTLS some more successful than others. The problems with the existing solutions and restrictions on mass adoption were:
- Location precision
- Power consumption
- Interference and multi-path
- Environment dependent tailor-made systems
Decawave, a pioneering fabless semiconductor company from Ireland, solved all these problems by developing the DW1000; a complete, single chip CMOS Ultra-Wideband IC based on the IEEE 802.15.4 UWB standard.
Why choose Ultra-Wide Band (IR-UWB) ?
Ability to very precisely measure the time of flight of the radio signal from transmitter to receiver => very accurate distance measurements (range & precision) – orders of magnitude more precise than existing systems. The DW1000 chip allows Direct Path to be identified even if it is severely attenuated relative to other indirect paths.
- Smaller Silicon Implementation hence cheaper and lower power
- Operates using up to 12 times lower energy in transmit & 7 times lower energy in receive than competing narrowband solutions
- Can locate items within 10 cm of where they are, and highly reliable
- LOS approx. 300m, NLOS 30m (indoor 3 office type walls), allowing it to be deployed in WLAN APs
- Can identify up to 11,000 items within a 20 meter radius
- Both Two way and One way and ranging capability, hence using wireless synchronisation no wired sync. infrastructure required
- Very high immunity to multi path fading, allowing easy installation for end user
- Avoids spectral crowding of the ISM bands (WiFi etc) since UWB does not operate in these bands so no interference with WiFi installations