Imporving the accuracy of your GPSr.

[+Glenn]

Anyone in to opening up your GPSr and messing around with its innards?

 

I've been thinking about finding an old GPSr and seeing what I can do to improve its accuracy. I know that the clock is one factor. What are some other things, circuitry wise, that affect the accuracy of a GPSr?

 

- Lone Rangers

[DisQuoi]

I'm guessing that any modification you make will likely result ina reduction in accuracy. The engineers that slapped it together probably considered such things as accuracy. If you CAN improve the accuracy, be sure to sell your improvement to the manufacturer as it would certainly be worth alot of money to them.

[+Macro]

In the days of discreet component boards, I would have suggested replacing the components on the circuit board with higher quality (meaning higher tolerance) components. I used to do this with audio amplifiers many years ago, and always improved the sound. For a GPSR however, unless you dont need your spare, I would say that tinkering with it will probably render it useless, unless of course you are an electrical engineer with a lab, then things might go just fine. Since these boards are primarily IC based, you would need to find a manufacturer of "high performance" IC's and replace the ones that came from the factory. No idea if this would effect accuracy, but I suppose for a few bucks it might be worth a shot. I doubt you will be able to get a schematic for your GPS, so locating the reciever components may be difficult. If possible, determine what the optimum input impedance of the antenna is, and then use a function generator with a scope, and verify that the Z(in) is acceptable. That is you biggest factor in reception, impedance matching for the input signal.

 

Good luck, let us know what you find.

[Kerry.]

Circuitry wise, very little to non existent.

 

Just about everything that affects GPS accuracy these days are on the outside not the inside and most of these are untouchables. Accuracy by far is much more dependent on Satellite clock stability, Emphemeris prediction models, Ionospheric noise, Tropospheric delay, Multipath and Noise all of which we really have no control over.

 

Basically in terms of accuracy, all handheld GPS receivers are created equal. That have the same basic parts and use the same signals. It's what they do with what they get that makes the difference but the software is also an untouchable.

 

As for the clock in a GPS it does not much more than tell the time where as the timing is something totally different and also basically untouchable.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[Kerry.]

Circuitry wise, very little to non existent.

 

Just about everything that affects GPS accuracy these days are on the outside not the inside and most of these are untouchables. Accuracy by far is much more dependent on Satellite clock stability, Emphemeris prediction models, Ionospheric noise, Tropospheric delay, Multipath and Noise all of which we really have no control over.

 

Basically in terms of accuracy, all handheld GPS receivers are created equal. That have the same basic parts and use the same signals. It's what they do with what they get that makes the difference but the software is also an untouchable.

 

As for the clock in a GPS it does not much more than tell the time where as the timing is something totally different and also basically untouchable.

 

Cheers, Kerry.

 

I never get lost everybody keeps telling me where to go

[+threelanes]

I'm sure that's all it would take to boost one of those old fashioned receivers into the 21th century.

 

Tom

[+threelanes]

I'm sure that's all it would take to boost one of those old fashioned receivers into the 21th century.

 

Tom

[peter]

I wouldn't recommend the cell phone add-ons, but I do agree that the antenna is the best place to make an improvement. If your GPSr won't accept an external antenna, you can still use the type the re-radiates the signal and allows your GPSr to pick up a much stronger signal. There are several commercial products and also some do it yourself plans on the web and amateur radio magazines.

If you're willing to take the chance of opening up the case and fiddling around, then you could try replacing the stock antenna with a more sensitive design - again check the web and amateur radio resources.