There are 2 concepts in LE, Advertisements and Scan (device can do both at the same time). The device that scans receives the ID (Bluetooth device address), RSSI and up to 31 bytes of information that advertiser decided to stick in to the advertisement packets. For example device which sends advertisements can advertise its location (see Location and Navigation sample). There is a bit of a complication with the ID because for security device can change its Bluetooth device address every so often so that not everybody but only bonded devices can track.
This is what is available today. In the future version of BT if scanner/observer or advertiser/broadcaster has several antennas they can figure out the direction (angle or arrival, angle of departure), but this is not yet available.
