Location-Based Services – Technologies

copyrights:Aleksander Buczkowski 2011-2012

Positioning Technologies

Positioning is a crucial component with Location Based Services as it allows get information about the location of the mobile device. The development of satellite systems (GPS, Galileo, Glonass) revolutionized the accuracy of location information, however for many LBS applications the GSM-positioning accuracy level is more than enough. From the marketing point of view the current popularization of the indoor mobile positioning applications seems to bring perspectives of a significant value especially for department stores, shopping malls, airports etc. The topic of positioning technologies has been already comprehensively researched. This chapter will summarize the technologies that are commercially used in Location Based Marketing applications.  Top OS and/or devices producers (including iPhone and Android devices) use hybrid positioning systems that involves combining several positioning technologies GPS, Cell ID, and/or Wi-Fi to deliver a reliable, accurate, cost-efficient location within a mobile application at all times.

In November 2011 Google introduced the first version of mobile indoor Google Maps for Android platform. Soon other major players in the market including Nokia started to reveal plans of expansion in this area. This intense activity around indoor positioning is indicating development of indoor Location Based Marketing in the near future.

Cell ID

The Cell ID (or Cell-of- origin) is the simplest localization method available in cellular networks. Mobile operator is identifying position of a mobile terminal through the id of the base transceiver station (BTS) that user connected at particular moment. Unless the capacity of BTS is not used, the user should be connected to the network via the nearest base station. “The accuracy of the Cell ID method therefore depends on the known range of the particular BTS serving the user at the time of the query. It can range from a few hundred meters in urban areas to several kilometers in rural areas”. A very prominent user of Cell ID positioning technology on mobile devices is Google. Google’s Maps for Mobile service uses the transmission from a single cell tower to provide the cell phone location.

Enhanced Cell ID

Enhanced Cell ID refers to technologies that are using position of multiple BTS stations or additional parameters of BTS signal to enhance the accuracy of the mobile terminal. There are several methods that utilize time (distance) or/and angles of radio signals. The most known are: AOA(Angle of Arrival),  TDOA (Time Difference of Arrival), TOA (Time of Arrival). Methods that are being employed depend solely on the cellular networks operators, the accuracy of the system might be required by legislators.

Global Positioning System (GPS)

GPS is a satellite positioning system controlled by the US Department of Defense. It consists of a constellation of 31 satellites. Although there are other similar projects, including European GALILEO, Russian GLONASS, Chinese Beidou the only worldwide broadly used system is GPS. The system determines the position of a receiver by calculating differences in the times that take signals from different at least three satellites to reach the mobile device with GPS antenna. Afterwards the system uses the mathematical technique of trilateration to determine user position, speed, and elevation. Despite good accuracy, GPS has some disadvantages: accuracy depends on the number of visible satellites; set-up time can be quite long, many minutes in the worst case; power consumption can be high; GPS does not work indoor or when satellites are in shadow.

Assisted GPS (A-GPS)

A-GPS is linking satellite positioning with GSM operators positioning systems. A-GPS requires BTS stations to be equipped with GPS receivers. In this way BTSs can provide information about visible satellites, allowing the GPS installed on the mobile device to speed up its tracking phase.  It addresses the key drawback of GPS technology – reduces power consumption and Time To First Fix (TTFF) that depending on a device, environment and sky visibility can take even a few minutes. Additionally A-GPS can provide better location accuracy than regular GPS because of use of differential GPS. This technique exploits the knowledge of both the actual BTS position and its GPS approximation to estimate GPS error and as a result, this error can be corrected applying a suitable correction factor.

In practice, there is a multitude of ways in which this technology can be deployed depending on the configuration of chipset manufacturers, local legislation, and operator policy resulting variation in its effectiveness compared to GPS.

 Wi-Fi & Bluetooth

Ubiquity of Wi-Fi access points inside buildings and in urban areas made it possible to utilize this data for positioning purposes. The technology uses similar methods as cell-id and triangulation but it applies them to wireless internet hotspots. When a mobile device detects the Wi-Fi signal, preinstalled positioning software scans it and compare to reference database, than based on the strength of one or several signals, it calculates user’s location. Bluetooth technology works in a similar way however, it requires to install a grid of antennas, as the technology is as popular as Wi-Fi. Private companies including Skyhook and Google are gathering data with special vehicles that have extra-sensitive GPS and Wi-Fi receivers. The technology has been widely used starting from Apple iPhone 2G and then adapted by other smartphone producers. Wi-Fi has been shown to achieve 3-10 meter indoor and 20-30m outdoor positioning accuracy. The achievable accuracy depends on two factors: access point density and the location-positioning algorithms employed.

Near Field Communication

Within the concept of proximity marketing Near Field Communication (NFC) is gaining importance as major smartphone producers start to add this technology to the latest device models. NFC is a very short-range wireless connectivity technology designed for cell phones and credit cards. It establishes radio communication between to devices or a device and NFC chip by touching them together or bringing them into close proximity, usually no more than a few centimeters.

Geofencing

Geofencing is one of key technologies used in Location Based Marketing. It refers to a virtual boundary created around a specified physical location or point on a map. It is used to test whether presence inside the area is true or false in order to trigger some sort of predefined action, which in case of marketing refers to sending targeted message Geofence can be defined by a series of lat/long coordinates or radius of a particular distance around a specific point.

Three primary types of geofences:

  • Static: user’s position relative to a fixed point or fixed area
  • Dynamic: user’s position relative to a changing data stream
  • Peer-to-Peer: user’s position relative to other users

Static geofencing can be used to send an special offer via text message to opt-in users as they enter a shopping district, dynamic geofencing to send a message about “open parking space” nearby mobile app users driving through particular area, and peer-to-peer geofencing in a location based social network to notify user about friends nearby.

In the corporate world, geofences are used to alert management when employees leave or enter pre-determined area. On a personal level, a geofence can alert parents when your child arrives at school, via an application such as Neer. In Location Based Marketing geofences are used mostly to send messages to opt-in users when they enter particular area. Check-in applications are as well using geofencing to verify if users are within a particular distance from the venue they are checking in.