[time-nuts] Looking at ultra precise 50 km-100 km Electronic Distance Measurement.

[Patrick Barthelow]

Looking to increase accuracy of a microwave transceiver pair designed to
measure very long distances  (*up to even 100km, Line of sight)
They send a microwave carrier, modulated by HF radio modulation sine waves.
To an identical Transceiver at the far end. Which sends the modulated
carrier back. and phase comparisons of emitted and returned sigs are
compared and precisely quantified.   Most instrument specs from the old
days are still pretty good,  +-  a centimeter or so, and a ppm variation
with total distance. --In 40-60km  High accuracy stuff  needs good
meteorology data along the line measured, which affects c = speed of radio
waves at the time of measurement.
The Modulation frequencies need to be either monitored continuously and/or
need to be stable to assigned values.   Trying to modify internal frequency
reference of a pretty old system to  GPSDO accuracy.
Anyone here that has done  EDM work in surveying  or Geodesy, etc?
Best, 73,   Pat Barthelow AA6EG
apol <apolloeme at gmail.com>loeme at gmail.com


*"The most exciting phrase to hear in Science, the one that heraldsnew
discoveries,  is not "Eureka, I have found it!"    but:*
"That's funny..."  ----Isaac Asimov