Forward link repeater delay watermarking system

A method for determining position location of a mobile station using forward link pilot signals, including repeater-screening the forward link pilot signals to determine repeater information, the method comprising:

• modulating a plurality of forward link signals at a repeater with a time-varying delay element to watermark repeater information thereon;
• receiving a plurality of forward link pilot signals in the mobile station, including taking pilot phase measurements therefrom;
• estimating a time delay of said plurality of forward link pilot signals over a period of time;
• performing repeater identification in the mobile station responsive to said time delay over a period of time to identify whether the forward link signal is repeated;
• determining if sufficient repeater-screened forward link pilot phase measurements have been obtained for position location determination;
• if sufficient repeater-screened forward link pilot phase measurements have not been obtained for position location determination, then repeating said steps of estimating a time delay and performing repeater identification on one or more other received forward link signals until sufficient repeater-screened pilot phase measurements have been obtained for position location determination;
• correcting said pilot phase measurements including substantially removing said estimated time delay from forward link signals identified as repeated;
• and
• providing pilot phase measurements and repeater information, if any, for the forward link signals to one of a position determining system and a position determining entity to determine the position of said mobile station.

A mobile station for determining position location, including repeater-screening forward link signals to determine repeater information about the forward link signals, said mobile station comprising:

• a receiver that receives a plurality of forward link pilot signals, including taking pilot phase measurements;
• a time delay estimator that estimates a time delay waveform on said plurality of forward link pilot signals;
• and
• a repeater identification system that receives said time delay waveforms, correlates said time delay waveforms with repeater information to identify repeated signals, and removes said time delay waveform from said pilot phase measurements of repeated FL signals before sending repeater information and pilot phase measurements to one of a position determining system and network position determining entity to determining the position of the mobile station.