A cellphone system comprises a GPS reference station located with a
telephone cell site. Such GPS reference station tracks the GPS satellites
visible to its local area and estimates the Doppler for each such GPS
satellite. The system also includes mobile GPS receivers and cellphones
that move around and through the operational area of the cell site. It is
assumed that the satellite Dopplers seen by the GPS reference station
will have insubstantial differences with the true Dopplers observed by
other GPS receivers operating within the cell site's service area. The
Doppler estimates are thus routinely communicated over a wireless
telephone channel to the mobile GPS receivers and cellphones that
register locally. Such mobile GPS receivers then can confidently adopt
the surrogate Doppler estimates as a center starting point for their
initialization frequency searches. The time required for such mobile GPS
receivers and cellphones to initialize and provide a first fix is thereby
substantially reduced.