Patent ID: 7256737
Filing Date: 2007-08-14
Classification: G01S,H04M,H04W

Abstract:
1. A method for determining the location of a transmitting unit transmitting a signal, comprising: (a) transforming the signal received at a first site to a frequency domain representation comprising first component signals each having a frequency and a phase angle parameter and transforming the signal received at a second site to a frequency domain representation comprising second component signals each having a frequency and a phase angle parameter; (b) operating in the frequency domain, determining a Hermitian product of first and second component signals having a same frequency parameter; (c) operating in the frequency domain, determining a phase angle parameter of each Hermitian product determined at the step (b); (d) determining a relationship between the phase angle parameter and the frequency parameter for a plurality of Hermitian products; (e) determining a time difference of arrival of the signal from the relationship. (f) selecting a location estimate for the transmitting unit; (g) determining a distance difference of arrival from the location estimate to the first and the second sites, the distance difference of arrival responsive to the time difference of arrival; (h) determining an error in the location estimate in response to the distance difference of arrival value; and (i) updating the location estimate in response to the error.