The present invention relates to a navigation unit and base station used for determining location. A plurality of base stations are initialized to determine their location relative to each other. At the navigation unit, the time of arrival of at least one signal from each of the plurality of base stations is measured. From this, the location of the navigation unit relative to the plurality of base stations may be directly calculated using a closed solution. In one embodiment, a time of arrival technique is used and in another embodiment a time difference of arrival technique is used. Preferably an ultra-wide band frequency is utilized.