GPS Time and frequency reference: GPS Disciplined Oscillators

GPS Time and frequency reference: GPS Disciplined Oscillators













Relative Accuracy of Various Frequency References
Reference     Modification                  Accuracy Range
Crystal                                                  1 to 100 ppm
Crystal         TCXO                            ~ 0.1 ppm
Crystal         Ovenized OXCO             0.001 - 0.1 ppm
Crystal         Double Oven                   ~ 50 ppt (parts per trillion)
Crystal         GPS supervised OXCO  ~ 5 ppt
Rubidium                                            ~ 50 ppt
Rubidium     GPS supervised              ~ 5 ppt
Cesium                                               0.01 to 0.1 ppt
Hydrogen Maser  Passive                  1 ppt
Hydrogen Maser  Active                      0.0007 ppt
ppt= parts per trillion, one part in 10(-12) = ns

One second per year =1/31,536000 = 0.000000031709792 = 3.2x10(-8) = 3.2 ppt








https://vk4zxi.blogspot.com/search/label/GPS%20disciplined

http://www.ke5fx.com/heather/readme.htm
https://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/

http://www.rtklib.com/rtklib.htm
https://rtklibexplorer.wordpress.com/resources/

Comments

Post a Comment

Popular posts from this blog

Seiko Vibron Tuning Fork Clock c1960s-70s

Image
Significance A Seiko clock using a tuning fork and mechanical movement, powered by a battery and single transistor drive. Made in Japan in the 1960s to early 70s in the brief period after transistors became available and before they were replaced by quartz clocks. Description The Seiko Vibron VBZ-208 is an electronic-mechanical, 6-jewel clock that uses a 150 Hz vibration, H-shaped, double-ended tuning fork. The tuning fork element was developed by Seiko to be virtually immune to changes in temperature being made of a special alloy. A single transistor switch drives a solenoid to magnetically excite the tuning fork. The other end of the tuning fork has two magnets, along with a rotating disk that constitutes a synchronous motor that then drives the gears set to the hands. The movement offers extremely high timekeeping precision. The clock is big and heavy, around 2 kg, indicating it was probably quite expensive when new. The face is metal rather than plastic with a metal finish.
Read more

Lenzkirch Wall Clock 1 Million Fusee late 1890s

Image
Significance A Fusee Lenzkirch Wall Clock, 1 Million series 21 movement, late 1890s. Lenzkirch used mass-production to make high-quality clocks in the Black Forest region of Germany from 1860 to 1932. A fusee movement in the 1890s is unusual in the 1890s as steel springs had improved from the 1850s that were sufficiently accurate for most makers. However, a few quality makers continued with fusee as well as improved springs. Fusee were used in most marine chronometers until they became obsolete. Lenzkirch clocks have few maker's marks, but the "1 Million" above the serial number is characteristic, along with 21 for the movement series. Description A high quality 300 mm wall clock with a short pendulum inside the case with a fusee movement. The dial surround is solid timber. The movement frame is a solid brass sheet. Local pickup through online Gumtree classifieds. Notes http://antique-clock.com/about/lenzkirch http://www.clockguy.com/SiteRelated/SiteRefere
Read more

Suko Artempo Handless Clock c1990

Image
Significance Modern quartz clocks can be cute too! A novelty clock. Suko made a number of similar designs using the same principal. Description A novel design. Italian I think. The dial rotates around the spindle with the time indicated at the spindle. I think the white "hands" have been added as they are not on other clocks. A year 2000 clock is available but I have yet to get one. Source Ebay, Melbourne, Australia.
Read more