Hybrid Positioning System (xps) - Seminar Report

ABSTRACT:   

                        Our ancestors had to go to pretty extreme measures to keep from getting lost. They erected monumental landmarks, laboriously drafted detailed maps and learned to read the stars in the night sky. But things are much, much easier today. You can know exactly where you are on Earth at any moment with the help of positioning system like and hence you'll never be lost again. Towards this aim, several technologies exist, ranging from personal area networking, to indoor, outdoor, and up to geographic area systems.Inspite of the pool of positioning technologies ,we are in search of “THE BEST” technology .                         

                     Towards this aim, the paper proposes a HYBRID POSITIONING SYSTEM which is the combination of several positioning system existing around the globe. This hybrid positioning system is the best, because it takes into account the merits of several positioning systems like GPS, Wi-Fi, cell tower triangulation and many more. Therefore overcomes or solves all the inefficiency problems and provides more accuracy. The positioning system has proven possibility of providing positional information with high accuracy as a complementary system of GPS even in the areas where GPS signal is not available.

                        XPS is a software-only location platform based on Wi-Fi positioning, GPS and Cell tower triangulation.XPS is available world wide and can be deployed on a broad range of mobile devices. Hence a mobile device with XPS client collects raw data from each of the signal sources and sends the information to the XPS server. As a result a single location is estimated and returned to the mobile device.XPS is able to quickly and accurately calculate location regardless of the physical environment. The XPS database is created by collecting all the Wi-Fi access points and cellular tower IDS in the particular area, hence the XPS system is always expanding. Hence the customers can easily locate the position in both indoor and dense urban areas.

                  The commercial application of XPS is that of the Global positioning system and Wi-Fi, but the basic difference lies in the accuracy, efficiency and liability. To cite the application includes navigation, locating the position through iphones, vehicle tracking and many more.

Hence the hybrid positioning system is Accurate, Available and Reliable.

Introduction:

Hybrid positioning systems are systems for finding the location of a mobile device using several different positioning technologies combined with cell tower signals, wireless internet signals, Bluetooth sensors or other local Positioning Systems.These systems are specifically designed to overcome the limitations of GPS, which is very exact in open areas, but works poorly indoors or between tall buildings (due to the urban canyon effect) By comparison, cell tower signals are not hindered by buildings or bad weather, but usually provide less precise positioning. Wi-Fi signals may give very exact positioning, but only in urban areas with high Wi-Fi density - and depend on a comprehensive database of Wi-Fi access points.Hybrid positioning systems are increasingly explored for certain civilian and commercial location-based services and location-based media. which need to work well in urban areas in order to be commercially and practically viable.

Different hybrid positioning systems are currently being developed and used in services from Navizon, Xtify, PlaceEngine, SkyHook, Google Maps for Mobile for application in smartphones including Apple iPhone. The maturity of these systems approaches requires proofing in operational use.

skyhook's xps:

Skyhook was founded in 2003 to capitalize on the increasing demand for location-based services. The first location technologies, GPS and cell tower triangulation, were inadequate - leaving frustrated mobile consumers with slow and inaccurate positioning information. In response, Skyhook developed the Wi-Fi Positioning System (WPS). Taking advantage of the hundreds of millions of Wi-Fi access points throughout populated areas, WPS consistently provides accurate location information indoors and in urban areas.

Skyhook also provides XPS, the world's first true hybrid positioning system. Taking advantage of the relative strengths of several location technologies, WPS, GPS, cellular tower triangulation, XPS is the fastest, most accurate, most reliable and most flexible location system on the market today. Skyhook's patented XPS technology is positioned to location-enable hundreds of millions of applications and mobile devices, including smartphones, netbooks, laptops, and gaming devices. From traditional navigation apps to cutting edge augmented reality browsers, today's mobile applications require location that works reliably and quickly everywhere consumers travel, from rural to urban areas, indoors and outside. 

XPS is the only location system that meets today's consumer, developer and device maker demands for location performance. 

WORK:

XPS is a software-only location platform that can quickly determine the location of any Wi-Fi enabled mobile device with an accuracy or 10 to 20 meters. To see Skyhook's hybrid positoning system (XPS) in action, view a demo now:

To quickly and reliably arrive at accurate location results, XPS synthesizes data from Skyhook's Wi-Fi Positioning System (WPS), GPS satellites and Cell Towers with advanced hybrid positioning algorithms. By leveraging the strengths of more than one underlying position technology, XPS provides the best location available to mobile applications and devices today.

The following graph illustrates the performance of XPS relative to assisted GPS (A-GPS) and WPS.

 XPS is configured to integrate and synthesize the location output of Skyhook's Wi-Fi Positioning System (WPS), GPS and cellular towers (Cell ID). It then uses advanced hybrid positioning algorithms to combine each of these location sources to arrive at a single position with a high degree of confidence.

Wi-Fi Positioning System (WPS)

WPS determines location based on Skyhook's massive worldwide database of known Wi-Fi access points. It performs best where GPS is weakest, in urban areas and indoors. It is an essential element in any consumer-ready location system. Click here for details on Wi-Fi data collection methodology and coverage. 

GPS

GPS provides highly accurate location results in "open sky" environments, like rural areas and on highways. But in urban areas and indoors, tall buildings and ceilings block GPS' view of satellites, resulting in serious performance deficiencies in time to first fix, accuracy and availability. Mobile app developers and consumers now demand location information that is fast and accurate in all environments. GPS or A-GPS alone cannot meet these standards.

In deep urban settings, WPS can also take advantage of faint GPS signals to more accurately acquire location in just seconds.

Cell Tower Triangulation

Cell Tower Triangulation provides generalized location results with only 200 - 1000 meter accuracy. It serves as a coverage fallback when neither GPS nor WPS is available. Skyhook maintains a worldwide database of cell tower locations, which increases the XPS coverage area and helps improve GPS satellite acquisition time. Cell Tower Triangulation can also improve power utilization by helping XPS intelligently enable/disable communication radios depending on the location accuracy required.

COVERAGE:

To pinpoint location, XPS uses a massive reference network comprised of the known locations of over 100 million Wi-Fi access points and cellular towers. To develop this database, Skyhook has deployed drivers to survey every single street, highway, and alley in tens of thousands of cities and towns worldwide, scanning for Wi-Fi access points and cell towers plotting their precise geographic locations. Skyhook's extensive coverage area includes most major metro areas in North America, Europe, Asia, and Australia.

Wi-Fi Reference and Cellular Database

Skyhook's Wi-Fi and cellular database is the largest and most extensive in the world. Skyhook maintains the accuracy of this database through an ongoing and continuous process of data monitoring, analysis, and collection. The three main components are: 

1. Baseline Data Collection and Establishing Coverage Areas 

Data collection begins with identifying target geographic areas using population analysis. Skyhook territory planners build coverage schedules starting with population centers and then moving into residential and suburban areas.

Skyhook deploys a fleet of data collection vehicles to conduct a comprehensive access point survey within the target coverage areas. Every single passable street is included in the survey providing consistent coverage throughout the territory.

2. Automated Self-Healing Network 

Each location transaction starts with a scan for nearby access points and cell towers. The resulting access point information is then compared against the central reference network. Known access points and towers (those already in the reference network) are used to calculate the location of the device.

Any access point or cell tower that is either not in the database or was previously associated with a different geographic location is automatically identified and its current position entered into the database. In this manner, XPS automatically fixes and expands the reference network as it is being used.

3. Periodic Rescan 

Depending on the aging of the survey data and the density of user-generated updates, Skyhook periodically will rescan entire coverage areas to recalibrate the reference network, ensuring that performance remains consistent over time. Every territory added to Skyhook coverage is continuously monitored to assess the quality of the reference network and determine whether a rescan is required.

ARCHITECTURE:

There are two major components to the XPS system, the Mobile Location Client (MLC) and the XPS Location Server. The nature of the interaction between the two components and how often they communicate depends on the deployment model that is adopted.

Mobile Location Client

The Mobile Location Client is the software location engine of XPS. All applications and services request device location from the client. The MLC manages the entire process, from optimizing power management on the device to synchronizing reference data and calculating location. The client can operate in a fully autonomous mode or over the network with the Location Server.

Mobile Location Server

The Location Server plays a supporting role to the MLC, ensuring that the client has the most up-to-date reference data for its region. The Location Server can also execute positioning algorithms should the operator of the server prefer a network-centric approach. The server includes components for metering and tracking location requests in order to integrate with the operator's subscriber management and billing system. The server is designed to fit into any device maker or operator's existing location infrastructure. While many service providers choose to run the Location Server within their network, Skyhook also hosts a publicly available Location Server for providers that choose to minimize their cost and complexity. Developers who access XPS via the Skyhook SDK utilize the hosted server.

Configuration

XPS requires no new specialized hardware to operate on a device - only a "thin" software client, which can be easily configured to run on most mobile devices. This dramatically reduces the cost and time of deploying location-based applications or services in comparison with other positioning technologies. XPS complies with all location standards, simplifying the process of integrating with applications via standard interfaces, such as NMEA, and integrating within carrier networks via industry standards, such as SUPL. Device makers can employ many different configuration options to balance the needs for network availability, response time, and data storage in order to deliver the best user experience.

Click here to learn more about how XPS is configured to location-enable devices. Click here to see how XPS can add location to different applications and services.

PERFORMANCE:

PS provides a ubiquitous and reliable positioning system for any environment and use case. Contrary to other positioning systems, XPS performs exceptionally well in highly populated as well as indoor environments. The speed, reliability, accuracy and flexibility of XPS exceeds those of all other positioning systems.

Performance Table

XPS-GPS A-GPS

Accuracy 10 meters 10 meters 30 meters

Availability 99.8% 80.0% 95%

Time-To-First-Fix 1 sec 65 sec 30 sec

Unique technical differentiators

As a true hybrid positioning system that jointly optimizes raw location data from different sources, XPS 2.0 offers many distinct advantages over other hybrid systems. Some of these include:

1. Improving WPS accuracy by 35% in difficult environments, by leveraging signals from just two GPS satellites 

2. In deep urban settings, XPS uses weak GPS signals and WPS to acquire a location 100% of the time (A-GPS works only 70% of the time) 

3. From a complete cold start, XPS delivers a full hybrid location in 4 seconds (compared to 30-60 seconds for A-GPS) 

4. Combining GPS signals and WPS facilitate stationary detection techniques which reduce jitter, improving the pedestrian experience 

re are millions of iPhones on the market today. Despite stunning sales figures, the iPhone's initial adopters shared a complaint: that it lacked accurate location technology. Without location awareness, the device could not help users find their own location, provide meaningful local search, or instant directions from a users' current location.

Apple wanted to add a software-only location system to the Wi-Fi-enabled iPhone. It required superior performance, with quick time-to-fix and high accuracy in urban areas. Apple also required international coverage that would match the iPhone's international deployment.

Apple needed revolutionary positioning to match its revolutionary devices. It chose Skyhook's Wi-Fi Positioning System. Skyhook addressed Apple's needs by providing a highly accurate, reliable, commercial-grade positioning system that required no new hardware or complicated device integration.

When Apple's CEO Steve Jobs announced Wi-Fi location for Apple's mobile devices at Macworld in January 2008, he commented on the technology: "Isn't that cool? That's really cool.... And it works doggone well." After his announcement, Wi-Fi location became available to all iPhone and iPod touch users with a simple firmware upgrade.

1. On the left, iPhone without Skyhook: Imprecise and not acceptable to users 

2. On the right, iPhone with Skyhook: Accurate and meaningful for users 

iPhone 3G 

At the WWDC in June of 2008, Steve Jobs announced the revolutionary iPhone 3G. Skyhook's technology continues to be used on the iPhone 3G, as Jobs emphasized the importance of having all three dominant location technologies (GPS, WPS and Cell ID) on the iPhone: "Location services is going to be a really big deal on the iPhone -- you saw a bit of that here today, it's going to explode. We get location from cell towers, from WiFi, and now we get it from GPS."

The deployment of Skyhook's location system on millions of iPhones and iPod touch devices has won accolades from consumers, analysts, and the press worldwide.