Patent attributes
A displacement device for mapping wireless signal fingerprints includes motion sensors and at least one of a received signal strength indicator (RSSI) sensor and a round trip time (RTT) sensor. The motion sensors may include a pedometer and one or more sensors to receive turn information. The start position of the displacement device is initialized and as the displacement device is moved through an environment, the position of each measurement location is determined using the initialized position and data from the motion sensors. The measurement position along with the RSSI and/or RTT measurement is stored in a database, from which a map can be generated. The position of the access point may be determined using the RSSI measurement or RTT measurement. Additionally, accumulated errors in the measurement position may be monitored and when greater than a threshold, a user may be prompted to reinitialize the position of the displacement device.
