Navigation system and method

A method for determining the position of a user terminal comprising:

• transmitting a signal containing information indicative of the location of the signal source, almanac data, timing and synchronization data (epoch) and clock correction data;
• receiving said signal at said user terminal;
• receiving said signal at a location remote from said signal source which is also remote from said user terminal;
• converting said signal at said remote location to an aiding signal containing information which identifies said signal source as well as the predicted Doppler data and the spatial coordinate data for said signal source;
• transmitting said aiding signal to said user terminal.

In a system for determining the position of a user terminal including:

• (1) means remote from said user terminal for transmitting a signal containing information indicative of the location of the signal transmitting means, almanac data, timing and synchronization data (epoch) and clock correction data;
• and
• (2) receiving means at said user terminal for receiving said transmitted signal:
• the improvement in said system comprising:
• (1) means remote from said signal transmitting means and said user terminal for receiving said transmitted signal and converting said transmitted signal to an aiding signal containing information which identifies said signal transmitting means as well as the predicted Doppler data and the spatial coordinate data for said signal transmitting means;
• and
• (2) means for transmitting said aiding signal to said user terminal;
• whereby the complexity of said receiving means may be relaxed.