A method for determining location using a hybrid satellite and wireless local area network, WLAN, positioning system, the method comprising: determining a set of possible WLAN based position estimates for a WLAN and satellite enabled device based on characteristics of radio signals transmitted from a plurality of WLAN access points ; obtaining raw satellite-based positioning system, SPS, measurements provided by a SPS receiver of the WLAN and satellite enabled device from at least two different satellites ; and using the raw SPS measurements from the at least two different satellites to determine the best WLAN based position estimate from the set of possible WLAN based position estimates, characterized by the step of using including applying each of the possible WLAN based position estimates to the raw SPS measurements and calculating an internal SPS receiver clock bias for each possible WLAN based position estimate, wherein substantially the same internal SPS receiver clock bias across the acquired satellites for a given WLAN based position estimate indicates a good position estimate that is consistent with the raw SPS measurements, and non-uniform values of internal SPS receiver clock bias across the acquired satellites for a given WLAN based position estimate indicates a poor position estimate that is not consistent with the raw SPS measurements, and eliminating possible WLAN based position estimates that are poor position estimates that are not consistent with the raw SPS measurements. determining a set of possible WLAN based position estimates for a WLAN and satellite enabled device based on characteristics of radio signals transmitted from a plurality of WLAN access points ; obtaining raw satellite-based positioning system, SPS, measurements provided by a SPS receiver of the WLAN and satellite enabled device from at least two different satellites ; and using the raw SPS measurements from the at least two different satellites to determine the best WLAN based position estimate from the set of possible WLAN based position estimates, characterized by the step of using including applying each of the possible WLAN based position estimates to the raw SPS measurements and calculating an internal SPS receiver clock bias for each possible WLAN based position estimate, wherein substantially the same internal SPS receiver clock bias across the acquired satellites for a given WLAN based position estimate indicates a good position estimate that is consistent with the raw SPS measurements, and non-uniform values of internal SPS receiver clock bias across the acquired satellites for a given WLAN based position estimate indicates a poor position estimate that is not consistent with the raw SPS measurements, and eliminating possible WLAN based position estimates that are poor position estimates that are not consistent with the raw SPS measurements. applying each of the possible WLAN based position estimates to the raw SPS measurements and calculating an internal SPS receiver clock bias for each possible WLAN based position estimate, wherein substantially the same internal SPS receiver clock bias across the acquired satellites for a given WLAN based position estimate indicates a good position estimate that is consistent with the raw SPS measurements, and non-uniform values of internal SPS receiver clock bias across the acquired satellites for a given WLAN based position estimate indicates a poor position estimate that is not consistent with the raw SPS measurements, and eliminating possible WLAN based position estimates that are poor position estimates that are not consistent with the raw SPS measurements. <EOS>