SAR Other System History and Present
● WHOI DIBOS and SIO capsules (1980-83)
● SIO AVATAR (1986), SIO AVATOC (1994)
● Webb transceiver
● JAMSTEC tomography transceivers
● IFREMER Thierry Terre, SARA
● New Zealand Mike Bold
● NOAA Chris Fox, Haru Matsumoto, low frequency, $15k
● WHOI ORB Ken Peal, RefTek in a ball (1998)
● SIO Orcutt and Constable LCheapo, $15k
● Cornell Chris Clark marine mammal sounds, $7k
SAR Clocks Requirements
● Stability Δf/f of 3 x 10-10/year = 10ms/year, Rb is 1 x 10-10
● Low net power 100mW or LESS!
● Rb takes 10-30W
● Requires a hybrid system:
― continuous low power oscillator coupled with higher precision intermittent standard
SAR Clocks low power oscillators
● Austron 300mW, in thermos stability 5 x 10-9/yr used by SIO, 50mm dia by 250 mm long
● SeaScan TCXO, 10-8?, 10mW, large size
● MCXO Q-Tech (DARPA) used by Chris Fox 7 x 10-9 over 6 months takes 10MHz cal input, digital interface, 25mW timing mode, 75mW frequency mode
● Omsk Russian OCXO 180mW (only low power OCXO, found, could insulate more?) distributed by Quartzlock (UK) ?
SAR Clocks Present hybrid system
● Present system used by SIO since 1981
･ Austron, 300mW
･ Rb, 10-30W for 10 minutes, 1/day
● Analysis of historical data indicates Rb needs to be on only once every 20 days or so for this system
● Therefore, need to find a low power oscillator, lower power than the Austron, so that the combination with a Rb draws less net power.
