Indoor Location and Positioning will be huge! Apple recently acquired WifiSlam for its indoor mapping and positioning technology. Why? Because we spend most of our time indoors, working, shopping, eating, at the mall, at the office, on campus, etc. Google already has Indoor Maps for many airports and shopping malls. The race is on. The explosion of Smartphones with built in sensors, accelerometer, gyro, wifi radios, and camera make indoor positioning possible.
GPS and Maps are great, but they only work outdoors and with clear line of sight to the sky. GPS was developed by the US military for battlefield location, and navigation for planes and ships. It uses 24 satellites orbiting 12,600 miles above the earth. Your GPS unit searches for 3 or 4 satellites to "lock" your position. Your GPS receiver "knows" the location of the satellites, because that information is included in satellite transmissions. It measures the time it takes for the signal from each satellite to reach your device, calculates the distance from each, then triangulates your position...and updates it every second in real time. GPS is still remarkable decades after it was developed.
You may have noticed that your Smartphone mapping system is much faster at findng your initial position than your car GPS. Why? Because your car GPS relies soley on GPS satellite signals. In heavily forested areas, or congested cities with tall buildings, it can take a long time to get a "GPS lock" on 3 or 4 satellites because the "line of sight" is blocked. Your Smartphone mapping system augments the GPS with cellular tower signals and known Wifi hotspot locations. These signals are available where GPS is hard to get. Your Smartphone searches for all types of signals, calculates which is most accurate, and provides your location on a map much faster than a regular car GPS. Smartphone GPS is truly amazing! But, Indoor Location is even more amazing. Now lets explore how it can be used, and understand how it works.
Why will indoor location be big? Because indoors is where we spend money, meet friends, and where business happens. How can indoor location be used?
Navigation – Navigating inside large shopping malls, museums, airports, office buildings, college campuses, manufacturing plants, conference and convention venues
Location sharing for Social or family apps – Sharing your location with family and friends at large, crowded locations, or meeting up after individual activities
Shopping list routing – Find specific aisle locations within stores for every item on your shopping list. Enter a search term to find location of any product.
Offers/Coupons – Receive discount coupons and offers for products and services you care about located in close proximity.
Games – Many mobile games could incorporate indoor location. Games like MyTown, Life is Crime, Tap City, Monopoly, and strategy games like Tower defense, Risk, Coalition Games, and other strategy games.
Advertising by location – Targeted advertising based on precise location, time, and interests.
Manufacturing/Inventory/Asset tracking – Track movements of machinery, expensive inventory, assets, robots, vehicles, etc.
Workforce location – Real time location of personnel like doctors, supervisors, technicians, team members. No more public intercom announcements asking Dr. Smith to call the Emergency Room.
Defense/Intelligence – Tracking team members and assets on missions, in the dark, or in crowded locations.
Fire and Police - First Responder team tracking in crowded or dark locations.
How does Indoor Location technology work? Your Smartphone contains many sensors and radio receivers that can pick up all kinds of signals. Indoor location technologies use some or all of these to calculate indoor position. There are many different technical approaches to indoor positioning, and there is no clear winner yet. Until one technology achieves ubiquity it is likely that application developers will need to support multiple approaches and use whatever is available in a particular location. Here is a brief overview of each technology.
Wifi Triangulation – Wifi Triangulation measures signal loss or strength from multiple wifi hotspots to triangulate position. It is not necessary to connect to these wifi hotspots, only to measure the signal strength. Your phone displays signal strength in terms of 3 or 4 bars, but inside it is actually measuring signal strength very precisely. These services have a database of known wifi hotspots, and adds new hotspots as they are discovered by users. Android makes the wifi signal API available to developers so they can build location application. Apple iOS does not, so iPhone developers need to rely on other sensors and technology.
GPS/Cellular/Wifi Triangulation – Uses inputs from GPS/Cellular/Wifi, when available, to determine position. This is important for smooth transition from outdoor to indoor positioning. Algorithims assign confidence rankings to all signals to determine which signal to use, and how to continually refine position.
Wifi Fingerprinting – Smartphones turn on wifi for a few seconds to get a Wifi Fingerprint and associate it with a Check-In location. Compares the current Wifi Fingerprint to a known database of Fingerprint/Location pairs. Often used in conjunction with Check-in services like Google Places or FourSquare. This allows a more accurate location within a building. For example, checking into a place like Westfield Mall has many different Wifi Fingerprints depending on where you are in the Mall. If your Wifi Fingerprint is not found in its database it will ask you to enter a new specific location.
Dedicated Beacons - Cheap, low power, radio beacons located at known positions within a building. The only purpose of the beacons is to transmit a unique signal that can be received by your Smartphone. Uses the same location triangulation methods as wifi, but can be more accurate due to their specific location and purpose. These radio beacons can transmit proprietary signals or standard Bluetooth 4.0 Low Energy aka BLE.
Bluetooth Sensors - Many electronic devices contain Bluetooth, including every smartphone. These Bluetooth sensors can read signals from dedicated beacons, or dynamically create a mesh network of Bluetooth signals that constantly corrects and refines relative position and location.
Tracking Sensors from known positions - Most smartphones contain multiple sensors including a compass, gyroscope, accelerometer, altimeter, and barometer. These sensors can measure your direction, turns, speed, and height above sea level to create a three dimensional view of your location. Starting with a known position from other methods such as GPS, cellular, or wifi which work outside, the smartphone sensors can be used to track your position inside a building.
Magnetic sensors - Magnetic sensors can pick up the Earth’s natural magnetic forces to determine lat/long position similar to the way a compass works, but two dimensional, and much more accurate.
LED Lights - lights in the ceiling can be programmed to pulse in milli-seconds, so fast the human eye can’t detect the pulse. But, your smartphone camera can detect the pulses and distinguish between different lights and triangulate your position. The LED lights each have a unique pulse fingerprint. They can be used with standard light fixtures and remain in fixed positions within the building, making it easy to calculate location.
Cameras - A ceiling or wall mounted camera within a building can cover up to 100 square meters. The camera on your smartphone can automatically take many snapshot photos per second. Object recognition software uses pattern matching to compare those smartphone snapshots to the wall-mounted camera to determine precise location.
In my next post I will present a fairly complete list of startups and companies that are providing indoor location services and which technologies they use. I believe there will be lots of winners in this space using a variety of different technologies, and focusing on many different vertical market segments.
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