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Ask Dr. Ramsey Faragher About Navigation/Positioning Technology
Dr. Ramsey Faragher graduated from the University of Cambridge in 2004 with a first-class degree in Experimental and Theoretical Physics. He then completed a PhD in 2007 at Cambridge in Opportunistic Radio Positioning under the direction of Dr. Peter Duffett-Smith, a world expert in this field. He is now a Principal Scientist at the BAE Systems Advanced Technology Centre specializing in positioning, navigation, sensor fusion and remote sensing technologies in the land, air, sea and space domains. We recently covered his NAVSOP project, an advanced positioning system that exploits existing transmissions such as Wi-Fi, TV, radio and mobile phone signals, to calculate the user’s location to within a few meters. Dr. Faragher has graciously agreed to answer any questions you may have about NAVSOP, the future of GPS, or what a theoretical physicist puts on his business card. Ask as many questions as you like, but please confine your questions to one per post.
He seems to have written a post on how this works and then later made an account. Sorta verified here. His post is very informative and might answer a lot of questions and generate more meaningful ones.
My work here is dung.
I'd imagine a lot of positioning calculations involve accounting for or adjusting for known effects or noise. For example, accounting for general relativity in GPS. What is the most surprising correction you've ever come across (even on an exam or done in theory)? Have you ever found yourself saying "I didn't think that could affect the calculations so much."
My work here is dung.
What kind of accuracy is possible to achieve using NAVSOP - or other systems you know of - if I can place stuff like APs, mobile phones, etc. myself in a factory area? Do you have methodology for designing placement of such devices so positioning accuracy is reached at every point? How low can one get with costs of such solutions?
Will there ever be a way to accurately use GPS without open sky access in a building or underground?
It would seem that to use this technology, the client would need to have a much larger datastore than with GPS: Whereas only the positions of the GPS satellites need to be known to make a calculation, the dataset here is in the many thousands to millions. In addition to the data required for map storage, it would seem any implimentation of this would require an internet connection to download the data in a geographically-restricted fashion. This opens the door to privacy issues that standalone GPS clients do not have.
How do you plan on addressing the privacy issue with your product?
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Something that surprises me is that we're so obsessed with the exact positioning of things on Earth but at great exo-solar distances, we seem to be okay with measurements to the nearest million light years. A couple days ago I read about a new method devised to measure location to within a few hundred meters of something 200 million kilometers away from Earth and it struck me as odd that more effort isn't put into this. While the practicality of Earthbound work is far greater, the implications for physics and verifying theories seems to be an obvious benefit for better positional measurements in space. I know satellites and objects near Earth are heavily measured but why isn't there more attention paid to precision of deep space objects? What problems prevent sensor fusion from being applied to space? Too much noise? No way to actually verify your results?
My work here is dung.
Hi, Dr Ramsey!
What is your best estimate as to what is the US DOD's current GPS backup system?
IIRC Obama cut the budget for LORAN around 2010 and till then the system was financed with the explicit explanation and purpose - GPS backup. But no more...
I am currently teaching ECDIS systems to mariners and I always emphasize the weaknesses of GPS under jamming. Ever since Selective Availability has been switched off, the jamming topic pops up more and more as a soft spot of the whole process, so I think we are not fooling ourselves that the US would let down such a gaping hole in its systems uncovered...
Now, Make Your WISE Move...