6Typical approach GPS based location Network based location significant amount of time to acquire an initial fixpower hungryNetwork based locationperform a scan for surrounding wifioffers relatively coarse grained location
7Performing passive wireless scans is the lowest energy operation compared to other location sensors. This motivates us to explore the wireless interface as a sensor to sense driver mobility.
8Sensing that the user has returned to the parked vehicle location. Detecting the user is in a moving vehicle after returning to the parking location.
9How to sense the user has returned to the parked vehicle location?
10User returning to vehicle wireless signature(why?)SSIDs of the Wifi access points.the number of times a beacon frame was received from each AP.capture a wireless signature during payment phase.
11User returning to vehicle periodically perform new wireless scans, create new signature.(St and Wt)Compare the signatureSt, Wt with Sp, WpOptimizedefine the signature over a set of scans rather than a single scan.AP was visible in all the scans gets a higher weightMatching function
12How to detect the user is in a moving vehicle after returning to the parking location?
14User driving away vehicle traveling follow a certain pattern what effect do these have on the wireless beacons observed by the mobile device inside the vehicle?compute the Jaccard similarity.
15Special CasesAfter parking, the driver drives away in a friend’s car,two cars are closed to each other.A driver parks a vehicle and give the key to someone else.The driver returns and unparks as expected, but immediately gets stuck in the traffic.
16-environment is dynamic 34/38 Sensing Accuracy38/41-environment is dynamic34/38-drive slowly
17EvaluationSignature Matching(accuracy of signature matching functions)