Patent ID: 8594018

Claim:
A ranging device comprising: an RF system integrated on a chip and including a receiver portion and a transmitter portion, the receiver portion comprising a preamble correlator coupled to a timing unit, the transmitter portion comprising a preamble SFD generator coupled to said timing unit: the preamble correlator providing a start of frame delimiter (SFD) indicator to the timing unit when the receiver portion detects a start of frame delimiter (SFD); the preamble SFD generator providing an internal indication of time of sending (TOS) a packet; the timing unit coupled to said preamble correlator to receive said start of frame delimiter (SFD) indicator from said preamble correlator and further coupled to said preamble SFD generator to receive said indication of time of sending (TOS) a packet; the timing unit configured to record a TOS stamp upon receiving said internal indication of time of sending (TOS) a packet from said preamble SFD generator; the timing unit further configured to record a TOA stamp upon receiving said start of frame delimiter (SFD) indicator from said preamble correlator, and a range calculator coupled to said timing unit to receive said TOA stamp and said TOS stamp from said timing unit, said range calculator providing an estimate of distance to a target determined, in part, on a time difference between said TOA stamp and said TOS stamp.