Measuring nanoseconds

[MarkT]

The GPS hardware that does that is not a 5V 20MHz CMOS part!  And its using correlation primarily,
ie phase measurement, not time measurement.

If you want time of flight with RF then you're asking for something like pozyx.io or one of the UWB chips
that are starting to appear.

UWB = ultra wide band, which is what you need for time of flight - narrow band has very poor time resolution
by its very nature.

[PandaSonicTech]

To get 1 ns time resolution, you will need some pretty high end hardware for the "front end".

A programmable gate array with a clock rate of 10 GHz or higher should be serviceable.

Ummm... I think your calculations are a bit off there

[MarkT]

You've revived a dead thread for no reason!

[Idahowalker]

https://www.instructables.com/id/625-Nanosecond-Resolution-Timer-for-Any-Microcontr/