General Information:

What is AtomicGPSClock?

AtomicGPSClock is a Visual Basic 6.0 application written for the Windows operating system that will read the NMEA standard output from a NMEA compliant GPS and use the date and time output to accurately set the system time. An accurate time is necessary when tracking satellites, and other astronomical activities. AtomicGPSClock will also log any changes made and based on the difference between clocks will automatically schedule time updates in order to maximize system clock accuracy. Many other undiscovered features will be added as soon as somebody comes up with them.

What do I need to make AtomicGPSClock work for me?
Any GPS that will output NMEA 2.0 over RS-232 and a PC running Windows(R) with an extra RS-232 port. For the development of this project I'm using the best priced GPS I could find, the Garmin eTrex. This handheld GPS will output several protocols via RS-232 and can be powered by an external power source. This being said you will also need the cable which is often an extra accessory.

What is the future of AtomicGPSClock?
Linux, HPUX, OpenVMS...

Links To More Information:

I want to find out more about the AtomicGPSClock project.

Then go to AtomicGPSClock at You will find binary releases, source, and as well as documentation (soon).

How is AtomicGPSClock licensed?
AtomicGPSClock is licensed under the GPL.
Where can I find more information about the eTrex?
Try the Garmin website. Remember, any GPS that will output the NMEA 2.0 protocol will work.
If you choose to go with the eTrex try looking here for a less expensive connector:
Try your favorite search engine too, look for "eTrex hacks", "eTrex modifications"...

How accurate is AtomicGPSClock?
I don't know yet, I'm hoping for +/-0.100 second.

How much will AtomicGPSClock cost me?
From nothing to at most $165.00 US Dollars is you shop around.

How should I install this at my location?

Take a look at the installation page, I have several ideas for securely setting up the GPS in a location where it can receive good satellite signals either indoors or out.

Protocol and GPS Notes:
Misc. notes page.

Data logs and theory of operation

Screen Shots:
Screen Shots of Software

NEWS and Contacts:

What is the current progress of AtomicGPSClock?
05.09.2003 - Realized that none of my clocks anywhere in my house were accurate, and I could use a GPS to get the time from the atomic clocks in the GPS satellites floating around this planet. And so AtomicGPSClock was born!
06.09.2003 - Did some research into the NMEA 2.0 standard.
12.09.2003 - Gathered the funds necessary to purchase a handheld GPS; and did so.
17.09.2003 - I set up this page for the first time.
18.09.2003 - Added install page.
22.09.2003 - Added  misc. notes page.
26.09.2003 - Released Version 0.0.1 Alpha - for standalone and mobile systems. Just to see the GUI
30.09.2003 - Released Version 0.0.2 Alpha - for standalone and mobile systems. Now decodes NMEA strings from a GPS!
03.10.2003 - Added more NMEA notes to misc. notes page.
15.10.2003 - Released Version 0.0.4 Alpha - for standalone and mobile systems. Will now set the clock.
15.10.2003 - Erratic GPS mouse (see misc. notes).
19.10.2003 - Added data logs and theory of operation page.

I would like to contribute to the project, what do I do?
Create an account on SourceForge, and then e-mail me through SourceForge. I do not like to give out my e-mail address because I hate spam, and SourceForge has a great way of handling this: E-Mail me through SourceForge. Logo