CONTENTSWhat is IPS?Why not GPS?GPS vs IPSChoosing Wi-Fi over other sensortechniquesWi-Fi FingerprintingUses of IPSConclusion
What is IPS?An indoor positioning system (IPS) is a networkof devices used to wirelessly locate objects orpeople inside a building.Instead of using satellites, an IPS relies onnearby anchors (nodes with a known position),which either actively locate tags or provideenvironmental context for devices to senseIPS can be entirely local to your Smartphone (orother portable navigation device). IPS, like GPS,can establish a location fix completelypassively.
Why not GPS?A satellite navigation is a system of satellitesthat provide autonomous geo-spatialpositioning with global coverage may betermed a global navigation satellitesystem (GNSS or GPS).GPS has two fundamental laws : They don’t work indoors They only really operate in two dimensionsGPS are generally not suitable to establishindoor locations, since microwaves will beattenuated and scattered by roofs, walls andother objects.
GPS vs IPSOutdoors, navigation relies for the most part on GPS, whose accuracy rangesfrom 1 to 10 meters. Indoors, because of attenuation and scattering, GPSfalls apart. And even outdoors, GPS is vertically challenged; it’s about one-third as accurate at pinpointing your elevation as it is at telling where you areon the ground.
Choosing Wi-Fi over other sensor techniquesGPS is suitable for the outdoor navigation, as the navigable spaces are wideenough. The accuracy positioning of GPS is between 6 and 12 meters 95%of the time. The problem is that the reception of the GPS signals is bad indensely build areas, including the indoor environment.Radio Frequency Identification (RFID) makes use of tags and readers, whichallow fast read/write data communication, but there is no real localizationand positioning involvedUltra Wide Band (UWB) offers fast, low-power and large capacity datatransfer. The advantage is that it is capable of very precise localization(near 15 cm) but it is rather expensiveFinally, The IEEE 802.11 (Wi-Fi) technology of data exchange proves to bethe most balanced, as the signal range of around 30-40 meter indoor isacceptable and its economic viability is stable.
Technique Range / accuracy Remarks(A)GPS Accuracy: + Low barrier entry 6.0 m - 10.0 m - Slow computation and processing time Very susceptible to reflectance and multi-pathsGSM / UMTS Range: + Globally available ≈ 35.0 km - Cell-based accuracyBluetooth Range: + High speed data transfer ≈ 100 m - Positioning via triangulation (no Accuracy:10 m – 20 objects into account),Explicit links m between devices requiredIR Range: - Short range of detection limits 0.7 m – 2.5 m infrastructure, No penetration of materials / multipath, Line of sight, Signal can be disturbed easilyIEEE 802.11 (Wi-Fi) Range: + Large scale available over the ≈ 32 m (indoor) world .Economical viable ≈ 95 m (outdoor) - High power consumption, Slightly Accuracy: 1 m – 5 m multipath susceptible
Wi-Fi FingerprintingFingerprinting is the process of position determination, using the receivedsignal strength at one point.This can be stored for each point, at given heights, although in this researchonly the height of about 1 metre above the floor is considered. Oncecollected in a database, the application can check at which position thereceiver is, and thus position the user.
Uses of IPSNavigation inside buildings, offices, industrial facilitiesLocation Based Services, such as sales, coupons, sweep stakes, time managementSpecial offers alertsCouponsSweep stakesTime management alertFind your buddy (friends, school classes etc.)Workforce solutions (personnel)Security (evacuation, calamities)Alarms and alerts (know where your colleagues are)Alarm applications in generalStore usage analysis and store optimizationStatistics, Tracking & TracingHotelsGamingEnergy Management; climate control and lighting control systemAudio visual info (museums)
ConclusionTo increase the accuracy of finding your location, mapping developersare considering methods of supplementing Wi-Fi signals. Using measuredWi-Fi signal strengths to develop Wi-Fi fingerprints is an area that hasbeen receiving attention from researchers, and is certainly a validapproach for indoor environments.Not only will it reduce the stress of getting lost, but this technology canalso inspire other services to improve your shopping experience. Forinstance, one of your favourite clothing stores at the mall can send acoupon to your phone when you pass by their doors.Already, indoor mapping is creating buzz as the hot technology of 2013.