GPS system using Ground antenna

hallo friends... This is mahesh kedari... I am thinking to design a GPS system using ground antennas.. I know that to launch this system will be very much challenging but still not impossible... I expect all of you guys to put your own views over it... here are my views for this system

this system will eliminate the use of satellite hence to reduce the cost of GPS system... in this system three (minimum) poles will be established around each city. What all user has to do is just to give the destination to this system.. system itself is expected to identify the position of user and guide its vehical according to minimum distance and minimum traffic... tracing the path will not be difficult as the software will store the map of all roads in the city and all location .. and using graph theory it is possible to trace the minimum distance path.. but identifying the exact location of user will be a real challenge.. i have mentioned 3 towers(minimum) because if they are covering the circular path then minimum 3 circles can define a unique point hence to identify the exact positon.. now the challenges are .1) uneven surface of the city 2) building creating shadow zone 3) reflections created by building and other towers

i think smart antennas can do the job.. but still can not give enough accuracy.. so please guys put your own view above this topic....(I'll add the information regularly that im getting on this topic ) ..... thank you..

Reply to
maheshbest
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Been tried many times. Always fails because of reflections and masking off ground objects. GPS from sats overcomes most problems, and works everywhere, not just in cities. Sats are already up there, funded by rich countries, just use them. Why re invent the wheel ?

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Reply to
Adrian Jansen

Thanks dear Adrian Jansen... its nice to get your first reply.. I think the reason behind this implemantation is .. satellite access is still very much costly.. and many countries can not afford for the same .. so i think for those countries this system will be very much helpfull and also the other countries which already are using satellite based GPS system will take the advantage of the low cost of this system...

please put any more views of yours on this topic .. thank you..

mahesh...

Adrian Jansen wrote:

Reply to
maheshbest

Thanks dear Adrian Jansen... its nice to get your first reply.. I think the reason behind this implemantation is .. satellite access is still very much costly.. and many countries can not afford for the same .. so i think for those countries this system will be very much helpfull and also the other countries which already are using satellite based GPS system will take the advantage of the low cost of this system...

please put any more views of yours on this topic .. thank you..

mahesh...

Adrian Jansen wrote:

Reply to
maheshbest

Isn't there already a GPS-like system used ground-based antennas... LORAN?

I've read LORAN is actually slowly dying, due to everyone changing over to GPS...

Reply to
Joel Kolstad

Problem is you need this kind of navigation the most in big cities. Big cities tend to have tall buildings, which really mess up the signal paths.

In our fair city there are dozens of very tall grain silos, usually in groups of four or more. The rounded side of a grain silo is just perfect-- no matter where you are there's some angle that will reflect off a silo. As you might imagine off-the-air TV and FM reception is spotty at best.

There are also problems with tropospheric ducting on humid days where the signals reflect off the ground and inversion layer. Sometimes we get TV signals from many hundred of miles away if the weather is just right between us.

For GPS you need a clear, unsmeared signal, not one that might have reached you through several different-length paths. That counts out most ground-based transmitters.

Reply to
Ancient_Hacker

I guess 3 towers would also prevent 3D elevation information. Perhaps many transmitters on cell phone towers would work but cost more and be more complex.

GS

Reply to
zekor

Anyone can access the existing GPS satellites for navigation, it costs you only the price of a receiver. When Galileo sats come on line, you are not even dependent on only one system. Where is the problem ?

Why not build on existing technology and infrastructure, and use your talents to make new innovations, rather than attempt to duplicate an existing system.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
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Reply to
Adrian Jansen

GPS is used to calculate elevation as well as x-y location. Are you going to be able to make a ground-based system that's accurate enough to measure elevation? My GPS is generally accurate to within a few feet at sea level. If you're going to replace it, I expect it to be either much more accurate or much cheaper. I doubt you can be much cheaper, so how will you achieve greater accuracy? My GPS is already accurate to within +/-10 ft (in the x-y plane). How are you going to achieve +/- 1 ft?

-- Mike --

Reply to
Mike

This guy is probably not old enough to remember the ground based GPS system. It was called LORAN, I think there are still some LORAN systems operating but I doubt anyone really uses it much. Before they turned off the "SA" on GPS LORAN might actually have been giving you better repeatability ... or so said the fishermen I knew.

Reply to
gfretwell

they used that before gps...

How are you going to get those antennas high enough that line-of-sight won't be a problem in built-up areas

multipath reception will be another problem.

Bye. Jasen

Reply to
jasen

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