A method comprising: identifying, by a mobile computing device, a set of beacons associated with a geofence, said computing device having at least a first processing unit, a second processing unit, and a memory area, said memory area storing accuracy thresholds each associated with at least one of a plurality of positioning modalities; and providing the first processing unit with the identified set of beacons; the first processing unit disabling the second processing unit, wherein the first processing unit consumes less power when operating than the second processing unit, and wherein the first processing unit performs the following operations while the second processing unit is disabled: determine a distance from the mobile computing device to a geofence using one of the positioning modalities; compare the determined distance with the accuracy threshold associated with said one of the positioning modalities; select at least one of the plurality of positioning modalities based on the comparison; and enable the second processing unit based on the selected positioning modality, wherein the mobile computing device implements the selected positioning modality to detect additional beacons; characterized in that: the mobile computing device defines each of the accuracy thresholds based on an accuracy of the positioning modality and a size of the geofence; and the first processor adjusts the accuracy thresholds for the positioning modalities based on observed success rates during prior use of the positioning modalities, each success rate being represented as a value indicating whether a location could be determined or as a radius of error associated with the determined location or as the speed of the fix. identifying, by a mobile computing device, a set of beacons associated with a geofence, said computing device having at least a first processing unit, a second processing unit, and a memory area, said memory area storing accuracy thresholds each associated with at least one of a plurality of positioning modalities; and providing the first processing unit with the identified set of beacons; the first processing unit disabling the second processing unit, wherein the first processing unit consumes less power when operating than the second processing unit, and wherein the first processing unit performs the following operations while the second processing unit is disabled: determine a distance from the mobile computing device to a geofence using one of the positioning modalities; compare the determined distance with the accuracy threshold associated with said one of the positioning modalities; select at least one of the plurality of positioning modalities based on the comparison; and enable the second processing unit based on the selected positioning modality, wherein the mobile computing device implements the selected positioning modality to detect additional beacons; characterized in that: the mobile computing device defines each of the accuracy thresholds based on an accuracy of the positioning modality and a size of the geofence; and the first processor adjusts the accuracy thresholds for the positioning modalities based on observed success rates during prior use of the positioning modalities, each success rate being represented as a value indicating whether a location could be determined or as a radius of error associated with the determined location or as the speed of the fix. determine a distance from the mobile computing device to a geofence using one of the positioning modalities; compare the determined distance with the accuracy threshold associated with said one of the positioning modalities; select at least one of the plurality of positioning modalities based on the comparison; and enable the second processing unit based on the selected positioning modality, wherein the mobile computing device implements the selected positioning modality to detect additional beacons; characterized in that: the mobile computing device defines each of the accuracy thresholds based on an accuracy of the positioning modality and a size of the geofence; and the first processor adjusts the accuracy thresholds for the positioning modalities based on observed success rates during prior use of the positioning modalities, each success rate being represented as a value indicating whether a location could be determined or as a radius of error associated with the determined location or as the speed of the fix. the mobile computing device defines each of the accuracy thresholds based on an accuracy of the positioning modality and a size of the geofence; and the first processor adjusts the accuracy thresholds for the positioning modalities based on observed success rates during prior use of the positioning modalities, each success rate being represented as a value indicating whether a location could be determined or as a radius of error associated with the determined location or as the speed of the fix.