| Electronics > Beginners |
| Antenna in atomic clock |
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| Domagoj T:
Are proper atomic clock even available to general public, or within purchasing power of an average civilian? I'm not talking radio clocks, but real caesium/rubidium stuff. |
| NivagSwerdna:
--- Quote from: Domagoj T on May 03, 2019, 02:29:20 pm ---Are proper atomic clock even available to general public, or within purchasing power of an average civilian? I'm not talking radio clocks, but real caesium/rubidium stuff. --- End quote --- GPS time transfer from Satellite is dirt cheap nowadays... if you can solve for position then you have already solved for time. You will find people here, that have a Rb frequency standard or even Caesium standard I believe!... and lots of GPSDO owners. On the whole it is easier to use someone else's standard and transfer it... e.g. Radio standards, GPS, .... |
| Domagoj T:
That's why I ask about the non radio (actual atomic) clocks. GPS satellites are in roughly 20 000 km orbits, so latency is at least 65 ms (more for slant range). Furthermore, while I'm pretty sure GPS sats keep correct time, the position calculation doesn't depend on the receiver getting the correct time, just that the clocks on the satellites are synced, since it's the time difference that matters for GPS. Since GPS receivers don't have a two way communication capability, adjusting for this 65+ ms latency to get the correct time is not possible. Frequency standards again don't need to keep time, just the beat, right? That's why I ask if real, full blown atomic clocks are available to mere mortals. I honestly don't know and don't really have an idea for a ballpark figure. |
| NivagSwerdna:
--- Quote from: Domagoj T on May 03, 2019, 03:21:27 pm ---...the position calculation doesn't depend on the receiver getting the correct time.. --- End quote --- To calculate the distance to the satellite requires the local time and this is solved for; basically in 4D (you need >=4 SV) |
| Domagoj T:
Only if you have an atomic clock synced with the satellite you are calculating against. Which is what we don't have at this point. |
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