Time Difference of Arrival
How it works
- Client sends timestamp to access point
- Access point calculates difference in time between sending and receiving
- 3 values allow location determination
This technology has proven itself to work better outdoor, since there are no multipath
issues in an outdoor environment.
TDoA requires proprietary hardware capable of handling the timestamps.
Most vendors, like Cisco, AeroScout and WhereNet have their proprietary systems which
are supported and implemented by the
perLocus FrameWork™.
How it works
- Clients measure the signal strength from nearby access points
- Samples are transmitted from the client to a processing unit which calculates the current position
- 3 different samples are sufficient to calculate the exact location
RSSI is preferred over TDoA when the site of installment is an indoor environment,
due to the larger differences in signal strength, which increases the accuracy with RSSI.
Generally, RSSI does not require specific hardware, which is proven by Ekahau’s Location Engine.
This makes it possible to deploy the solution on a already existing WiFi network.