Wifi geolocation algorithm

When the tracking device already has acquired satellite positions because it is constantly tracking it can find much faster an accurate position, this is a hot fix.

A battery-powered tracking device that has to work for multiple years will not frequently determine positions, it has to do cold fixes. Your smartphone that needs recharging after one day on the other hand can do hot fixes as it has the luxury to do GPS fixes frequently. Another advantage is that GPS works everywhere outdoors and there is no specific infrastructure required.

The downside is that this geolocation technology requires quite some energy because it has to listen to several satellites and this can take some time especially in the case of a cold fix.

Other disadvantages are that long distance communication can be interrupted by weather-related situations and its inability to work indoors. Where GPS can therefore be used as an outdoor positioning technology, WiFi and Bluetooth can be used side by side for positioning indoors. Bluetooth is a wireless short-range communications technology standard. The signals do not carry very far, even in optimal circumstances devices need to be within meters. Although Bluetooth has been around for two decades, its latest version, Bluetooth Low Energy BLE is making big strides in geolocation and positioning.

There are two options to localise a tracking device via BLE:. Geobeacons act as a location marker. These are devices emitting a BLE signal which tracking devices use to identify their location.

So when you install geobeacons on known locations, the beacon will broadcast their identifier. The tracking device nearby identifies the broadcaster, the geobeacon, and uses this to determine its position. Advantageous to geobeacons is the fact that there is no interaction required with existing IT infrastructure for communication. The beacon itself is the minimal infrastructure that has to be installed. This geolocation technology works accurately outdoors and indoors.

The more geobeacons you install , the more accurate the positioning of your asset will be. The main argument to use BLE technology is the fact that the battery lifetime is guaranteed for many years. This technology consumes very low power and can easily be installed into your existing logistics infrastructure.

A battery-powered beacon is much cheaper than installing wires in industrial zones, for which you might need to shut down processes and perform security checks. Gateways are installed on fixed locations and act as a location marker. These devices are used to localise tracking devices that are not necessarily connected to the internet. The tracking device transmits a BLE signal which is received by the gateway. The gateway will forward the unique identifier of the transmitting device to the cloud allowing it to be localised.

BLE localisation accuracy relies on determining the distance to a fixed marker. There are different approaches. The device can take over the location of the closest marker or it can estimate distances to all markers it can reach and do a triangulation to determine a position. There are also different techniques to determine the distance between two devices over BLE. What algorithm should I use? I can assume, however, the location of my neighbors routers does not change.

Improve this question. Kirk Kuykendall Kirk Kuykendall No piggybacking - just signal strength, which is legal to measure, right? I'm not going to be "googling" the wifi Add a comment. Active Oldest Votes. Improve this answer. Thanks Bill, this looks doable. With laptops I just realized the signal is sensitive to antennae orientation.

Not sure if this is true with cell phones. Would the location fix be good enough for the middle school use case? You can handle orientation but it gets more complicated and would need more readings. Consider instead using the maximum signal among all possible orientations at each point.

The middle school use case is an interesting variant in that it suggests doing your best to identify the WiFi sender locations and strengths once and for all. After that it's a triangulation exercise. One concern I have is that source strengths can vary, often unpredictably. That can really screw up the triangulation. Consider adding an initial screen for outlying low signals so they don't ruin the fix. Brad Nesom Brad Nesom In this context Kirk could actually verify the locations in his back yard independently i.

Ortwin Gentz Ortwin Gentz 10 10 bronze badges. This might not be a bad idea if he wanted to figure out where he is. But he is trying to figure out a way to collect the locations of the networks himself. Moreover, he is trying to triangulate his position based on the strength of the WiFi signals.

I am not sure if the commercial solutions do that. For the mentioned school pickup case, it would be the way to go.

Kirk, While I may be wrong, I think you're way over complicating things. BlinkyBill BlinkyBill 1, 1 1 gold badge 9 9 silver badges 19 19 bronze badges. I thought skyhook collected data via wardriving. I can't imagine them driving onto school roads, though I suppose those are public. Something like signal strength, demonstrated throughput, CPU usage, time connected to the network, etc. At least that was my understanding of how routing paths should be chosen.

The three main paramaters for any connection are bandwidth, latency and capacity. You need capacity because you want to avoid congested nodes even if they would have good bandwidth and latency. Not an answer, but more of a list of postulations, as this is the first place I have seen anyone talking about this.

I have pondered geolocation mesh networking for some time, as a method to reduce the "flood" problem. I have 2 more ideas to help with the issue about node desirability. The second one is a bit more harebrained..

This would require that after a packet is sent on a performance response would need to be sent back to the node that sent it. Reputations should be maintained by the nodes around a target node, the target node should have no way to alter what the surrounding nodes judge about its reputation. The performance reports, used to judge reputation, would need to be relayed back from the node that the target node forwarded the packet to.

This report would need to be encrypted in such a way that it could be understood by the originating node, but not altered by the target node.

Crazy idea to try to encourage the upkeep of nodes. Attach crypto-currency payments at a fixed value for each bit of data handled by a node. The faster that a node can relay data, the more money it makes.

Other thoughts on geolocated mesh networking involves the directory system. This is not a well considered thought yet, but:. And lastly. This would require some means for nodes to constantly offset their positions from that point using orbital mathematics.

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