Startup uses disruption of Earth's magnetic field for indoor positioning
arcticstartup.com
arcticstartup.com
To set this up, some guy comes down to the dock, takes your boat out, does a few 360's with known landmarks in site and compiles a table of how your boat's compass varies from standard magnetic north. Big things like the engine, generator, keel, etc will influence what your deviation chart looks like. Usually it's less than 4 degrees at each point of the compass IIRC.
So every place in the world has metal objects that create that place's own distinct deviation from where magnetic north should be. So perhaps that's what these guys are using. A known table of variation and then looking at the deviation.
What I wonder about is what happens when someone turns on a 12 amp vacuum cleaner, a monitor nearby goes into powersaving mode, someone moves their laptop or someone with their own cellphone walks past. These things emit magnetic fields, so I wonder how they've solved the problem of the local deviation changing constantly.
For some background, see these slides (PPTX): http://pub1.willowgarage.com/~konolige/cs225B/slides/09-sens... (via http://pr.willowgarage.com/wiki/CS225B/Handouts)
Are any of those magnetic disturbances even within an order of magnitude of a smartphone's compass threshold? I'm surprised that the disturbance from a skyscraper's skeleton would be detectable, and a computer monitor seems like even more of a stretch.
However, when toggling some apparatuses in my room, nothing happened. My laptop doesn't have a hard drive though, but even only centimetres from it, no change was measurable. Neither did anything happen near my lamps or the AC/DC transformator. The only place I measured a difference (<10%) was on the stove (why yes I'll put my smartphone worth hundreds of euros on a hot stove). However, this faded into the background at a distance of about 10 cm.
It amazes me that we are turning our phones into better tracking systems than we've ever used on wild animals. Whether it's sound fingerprinting, gps, WiFi tracking, or now magnetic disturbance tracking, your phone's location services is getting so it can tell within a few feet where you are at all times. (By 2016 FCC regulations make it a requirement that all phones locate themselves within 100m or so)
This has amazing potential for startups. If your phone knows you are at the gym, it can start your workout routine. If you are at the library, it can decrease the ringer volume. Now with inter-building location ramping up, the opportunities will only increase.
On a related note, this information can be requested by law enforcement without a warrant. Last year cell carriers handled over a million such requests. http://www.nytimes.com/2012/07/09/us/cell-carriers-see-uptic...
People wearing little electronic devices that allow law enforcement to determine their position and travel patterns over any period of time just by filling out a form and without a warrant. If you had told me 20 years ago this is where we'd be, I would have called you a paranoid nut-job.
Note that location services comprises many different technologies, not all of which can be turned off. Many of them are required for the phone to operate. The upcoming FCC regs, for instance, require 100m self-locating ability to always be on. I guess for things like 911 service?
Speaking of paranoia, there's also rumors that the FBI/black helicopter/MIB bunch can actually power-up your phone remotely, especially with some models. This sounds completely out-of-left-field to me, but who knows? Court docs show they can use your phone as a listening device even when you're not calling somebody, so I wouldn't put other things along these lines past them. There's probably a good reason Osama Bin Laden refused to have anybody associated with him possess a cell phone, whether it was used, had a battery in it, or not. Seems like I read something somewhere once about illuminating electronics gear with microwaves, then reading the signature of the radiation emitted. But it could have been in a pulp sci-fi novel. As I said, it's difficult to tell where reality ends and paranoia begins with this because reality is quickly catching up to the paranoia of just a few years ago. Who would have imagined sub-meter resolution on where you are? That's almost accurate enough to tell if you're wearing the phone in your jacket pocket or on your belt. Crazy stuff.
I do remember reading about locally fingerprinting an Off phone based on its passive radio response, and this seems feasible.
When the phone is On, total location privacy is out the window, as Ma Bell always knows what towers you're near and can triangulate. Everything else you've said can be (and probably is) implemented in invisible layers of software.
End-to-end privacy would be a nice step forward, but assuring this requires an auditable interface between the radio transceiver and the computer/sensors. Any fix for the location problem involves decoupling identity/billing from the physical infrastructure.
Wake on LAN (WoL) is a pretty common feature for network chipsets. I don't know anything about mobile networks (so take this as the semi-educated speculation that it is), but it wouldn't be a stretch to imagine WoL over 3G. It wouldn't have to be a feature advertised to end users of the SoC.
What it comes down to is "what does 'off' mean on a cell phone?"
Things such as lifts, vehicles, regularly changing stock levels... Or are these all considered negligible?
I use magnetometers with IMU's as part of my research and temporal disturbances of the magnetic field are a huge problem.
Anyway, this new method sounds awesome. Thanks for posting!
From 5.4.3, it actually looks like this kind of magnetic positioning system works better in an indoor environment with lots of magnetic perturbations. This method measures where the person has moved, not where they currently are against a fixed constellation (like GPS). I'm guessing you would need to activate the data collection at a known waypoint (e.g. the front door of a business) and then it could track your movements around a magnetically perturbed space.
An underground mine is really really really different to a subway network if you are only looking at it magnetically.
This will not work well with the typical use case: user is in a shopping mall, needs to go to the bathroom, wonders where the closest one is and where he is, stops walking, opens his phone and starts the app.
Expected outcome: the app says "toilets are 50 meters to the right".
If the app now tells the user "I have no idea where you are. Please walk in a random direction in a straight line for 20 meters and I will try to find out, then tell you where you are and where the closest toilets are, which means that you might have walked in the wrong direction to begin with", the user is not really happy.
Does anyone know why this couldn't be used for outside positioning, much like GPS? Is the information not detailed enough, or do we lack good enough sensors to detect the fine-grained differences especially given all the electromagnetic noise that modern cities for example create.
Edit: I just realized it's probably also because somebody would need to create a world-magnetic-field map, much like the street view cars driving all over the world.
The positioning is complicated by the drift over time (there's a "new" global model every five years and for specific times & locations interpolation is performed) and fluctuates daily (as the Earth turns there's a diurnal pulsing in the induced magnetic field).
This is where "a bit of signal processing" comes into play.
The good news is the maths, the field testing, and the application of it is all a good 50 years old.
Typical exploration mapping company:
http://mcpharinternational.com/services/mining-exploration/a...
High resolution gridded geophysics for the Northern Territory, magnetics, gravity, radiometrics, etc:
http://www.nt.gov.au/d/Minerals_Energy/Geoscience/index.cfm?...
And with enough sensors (4 magnetometers) you can reconstruct 3D trajectory.
The following thesis is fascinating and very instructive: http://pastel.archives-ouvertes.fr/docs/00/50/10/05/PDF/pdfV...
Chapter 5 is very instructive, in particular the section Measuring magnetic fields gradients to derive velocity.
Excerpts: If the body moves, then the sensed magnetic field must change according to Maxwell’s equations. If the magnetic measurements do not change significantly, then the solid body is not moving. This permits us to rule out velocity drifts in our estimation. Ultimately, this improves the position information obtained by integrating the velocity estimate.
Note that they don't use the raw magnetic field, but its gradients, i.e a physical quantity that is intrinsequely local. Filtering out the earth's magnetic fields becomes quite easy (I suppose..) since these gradients are fast-varying quantities in comparison. Kind of like when you use an accelerometer: gravity is low-frequency, motions are high-frequency.
I would not have expected that result, but thinking about it more it does make sense. They are estimating "where have I moved" using the local magnetic field, which is very different than how GPS works "where am I in relation to a fixed constellation".
This technology might disrupt indoor advertisement.
RFID is actually a family of technologies, typically defined by ISO standards, and operating over several distinct frequencies: 134kHz (LF), 13.56MHz (HF), and 900MHz (UHF). LF and HF use inductive coupling between the tag (transponder) and reader (transceiver) while UHF uses capacitive coupling. Theses technologies do not allow one to know a specific distance, but rather when a tag is in the field or not. So, when Wal-Mart uses UHF tags on their pallets, they don't know where the pallet is exactly in their warehouse, they simply know when the pallet has passed through their loading dock. I've seen some triathlon timing systems use UHF RFID, but they still use cameras in case of close finishes.
Hope that helps.
The two companies that are the most prevalent are MyLaps [1] and Westhold [2], although there are some others out there as well. Both of these are active systems that require that each competitor have a transponder on their vehicle.
GPS works because outside is an enormous, unfamiliar place with tens of billions of destinations. Inside is small, relatively familiar, and even a large building has, at most, hundreds of destinations.
Just watching the demo, it's super cool and super intelligent. But it doesn't look like it can do direction - it can only tell direction after you've walked a certain distance. How will it cope with large magnetic things that move - eg Forklift trucks, vehicles, trolleys, wire cages etc.
I don't buy it. Ikea is the only potential place I could see this being of use, and there's no way anyone's going to bake in an extra sensor to a smartphone on the offchance. Look how slow adoption NFC has seen and that's a MASSIVE problem with multiple applications and a clear financial incentive.
We're trying to solve exactly this problem in London, why you may ask? When you have millions of commuters using your network each day (Underground) and many of your stations are at 100% capacity then your only option is to manage the flow of passengers more efficiently.
You've also missed a key problem, accessibility. The sheer volume of tourists, elderly or parents with prams getting onto a carriage thats inefficient to their travel results in exacerbating delays on platforms, this example(and other technologies) is a possible way to reduce those problems.
And you're wrong, it's a big market. Every large store in the world wants customers to easily find things. Big-box retail has to be over $1 trillion in annual revenue; Walmart alone does upwards of $400 billion a year. Something that slightly increases purchases or customer satisfaction can have a giant impact.
Those places employ millions of people; just letting their own employees find things easily could save a lot of labor time. Ditto for letting employees do something more productive than helping people find things that their phones could lead them to.
But anyway... Stores actually put a lot of effort into spreading the essentials around, and making you walk as far as possible to find things. It's in their interests that you are lost and browsing all the other stuff that you could be buying, instead of just grabbing that milk and going.
I don't think indoor navigation is as big as NFC, but I can see people making at least a little bit of money at colleges (and, as someone else pointed out below, mass transit situations)
If all you can think of is Ikea, maybe hold off commenting until (you've actually read the article) others have opened your mind to more possibilities.
There's a number of questions I'd have about the stability of the data being collected and how quickly it'd go stale.
I'd bet the hard part is getting building owners to update things regularly. Who's going to remember to change the map when the grocery store moves the cereal from aisle 2 to aisle 7?
>magnetic data plus wifi data plus user behavior data
[1] http://www.newscientist.com/article/mg21328516.200-apps-glow...
Local changes to the magnetic field have been used for quite some time for purposes such as oil exploration. I remember talking to an old geologist/oil man about twenty years ago as he went about locating candidate areas to explore based on these fluctuations. He explained that they'd use magnetometers to map out underground "cracks", deposits and other features. To go from that from generating local location data by overlaying a map of some sort (whether it is a building or something else) is nothing less than trivial.
If you have any experience sailing you may have also witnessed the effect of large sunken metallic objects on the compass. Again, you could "navigate" by these effects "Hey we must be passing over the SS-Sunken Ship".
Gotta love patents.
So given that I would have to questions if the military don't already use something very similiar in submarines. Lets say I'd be very supprised if this was not being already utilised in some form or another in that feild.
Could this solved by combining the mapping process with the quadracopters that can autonomously fly through and map a building?