created by described by Lee et al. (2010), where the user themselves generate ‘crowd sourcing’, the data through a process known as around and ‘wardriving’. Wardriving involves driving passively listening for signals from access points and mapping the location with a GPS device. This data is sent back to the host company which allows other users to try and estimate their location by looking for the same radio fingerprint as that previously recorded. This only works where databases of access location exist, usually in large urban areas like cities. points’ Table 2.2: Comparison table of Wide Area Positioning Systems System Approach Accuracy Scale Cost Constraints (and precision) GPS RF TOA 15 m Global High Does not work indoors (Malik, 2009) Indoor GPS RF TOA 5-75 m Global High Requires pseudolites (Wang et al., 2008) Differential GPS RF TOA plus 3 5 m Global High Requires non – correction updates standard (Malik, 2009) receivers Assisted GPS RF TOA plus <10 to >100 m Global High Requires cellular other Wi-Fi or or Wi-Fi (Djuknic and Richton, 2002) cellular network connection Skyhook GPS, Wi-Fi and 10 to 1000m Depends on Free Requires smart Cellular dependent on areas mapped phone or PDA (Skyhook Wireless, 2011) triangulation available most urban – devices Navizon GPS, Wi-Fi and 10 to 1000m Depends on Low Requires smart Cellular dependent on areas mapped phone or PDA (Lee et al., 2010) triangulation available most urban – devices Rosum TV TDOA 5 50m Coverage of Low Need for signal – TV signals monitors, no (Malik, 2009) standardisation
created by ‘crowd sourcing’, described by Lee et al. (2010), where the user themselves generate the data through a process known as ‘wardriving’. Wardriving involves driving around and passively listening for signals from access points and mapping the location with a GPS device. This data is sent back to the host company which allows other users to try and estimate their location by looking for the same radio fingerprint as that previously recorded. This only works where databases of access points’ location exist, usually in large urban areas like cities. Table 2.2: Comparison table of Wide Area Positioning Systems System Approach Accuracy (and precision) Scale Cost Constraints GPS (Malik, 2009) RF TOA 15 m Global High Does not work indoors Indoor GPS (Wang et al., 2008) RF TOA 5-75 m Global High Requires pseudolites Differential GPS (Malik, 2009) RF TOA plus correction updates 3 – 5 m Global High Requires non standard receivers Assisted GPS (Djuknic and Richton, 2002) RF TOA plus other Wi-Fi or cellular <10 to >100 m Global High Requires cellular or Wi-Fi network connection Skyhook (Skyhook Wireless, 2011) GPS, Wi-Fi and Cellular triangulation 10 to 1000m dependent on available devices Depends on areas mapped – most urban Free Requires smart phone or PDA Navizon (Lee et al., 2010) GPS, Wi-Fi and Cellular triangulation 10 to 1000m dependent on available devices Depends on areas mapped – most urban Low Requires smart phone or PDA Rosum TV (Malik, 2009) TDOA 5 – 50m Coverage of TV signals Low Need for signal monitors, no standardisation
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