Time accuracy of GPS timestamp

[mathlan86]

Hello,

How accurate can the time of the GPS signal be resolved?

If i look at the actual RX timestamp I see a resolution of 10e-8 s.

At the LV Timestamp it will be the same.

Is it possible to reach a higher/ better time resolution?

e.g. 10e-9, 10e-10, ...

Or is the time resolution limited by the USRP?

thx

[Sam_Sharp]

According to Wikipedia: "GPS time is theoretically accurate to about 14 nanoseconds. However, most receivers lose accuracy in the interpretation of the signals and are only accurate to 100 nanoseconds."

[mcduff]

I believe that the GPS signal is updated every second, that is, at a 1 Hz rate. This clock is then synced to your local oscillator which usually is 10 or maybe 100 MHz. The accuracy depends on how accurate your clock is also.

Cheers,

mcduff

[Sam_Sharp]

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@mcduff wrote:

I believe that the GPS signal is updated every second, that is, at a 1 Hz rate. This clock is then synced to your local oscillator which usually is 10 or maybe 100 MHz. The accuracy depends on how accurate your clock is also.

Cheers,

mcduff

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I think (I'm really not very confident on this) that only applies to a GPS device that outputs NMEA data over serial (which, as you say, outputs every 1s). I think the poster is using the software defined radio to decode the GPS signal directly?

[mcduff]

Thanks for clearing that up. I thought the signals from the satellites were only broadcast once a second, not sure why I thought that.

Cheers,

mcduf