The Department of the Navy, through the U.S. Naval Observatory, is responsible for establishing, maintaining, and coordinating the astronomical reference frame(s) for celestial navigation and orientation of space systems.

The U.S. Naval Observatory, Washington, D.C. is the agency responsible for Precise Time and Time Interval (PTTI) reference values for the DoD and other governmental agencies, coordinating DoD timing capabilities, analysis, evaluation, and monitoring of Research and Development and Operational PTTI systems.

• Provides marine navigators with a standard, automated means of performing celestial navigation computations.
• The calculations are done to one-arcsecond precision (about 30 meters on the Earth's surface).
• The software is free for official use with a documented requirement.
• The software is authorized for use by the USN.
• Please see http://aa.usno.navy.mil/AA/DoD/software/stella.html for additional information.

• For use by scientists, engineers, and mission planners requiring high-precision astronomical data.
• MICA is the software counterpart of the Astronomical Almanac.
• The software produces one-milliarcsecond precision positions and other astronomical information.
• The software is free for official DoD use and $24.95 (US) to others.
• The software is easy to use.
• Please see http://aa.usno.navy.mil/AA/software/mica/micainfo.html for additional information.

• For use by mission planners, in simulators, schedulers, and operations requiring sun and moon horizon and equatorial coordinates; times of rise, set, transit, and twilight; and approximate illuminance.
• The software is free for official use.
• The software is a de facto standard (USAF, USN, USA)
• Please see http://aa.usno.navy.mil/AA/DoD/software/slac.html for additional information.

• For use by scientists, engineers, and mission planners observations.
• The hard cover book is free for official use with a documented requirement and less then $50 (US) to all others.
• The book is an authoritative reference for celestial body positions and other information.
• Please see http://aa.usno.navy.mil/AA/publication/docs/almanacs.html for additional information

• For use by air navigators.
• The books are distributed for USNO by National Imagery and Mapping Agency (NIMA)
• It is the official reference for celestial navigation by aviators.

• Provides the positions and motions of stars for navigation, guidance and tracking.
• Catalogs of bright stars to very high accuracy are available for applications such as space navigation.
• Catalogs of fainter stars to less accuracy but higher density are available for background determination, such as for near-Earth object searches.
• Many are on CD-ROM and some on the web at http://ad.usno.navy.mil/ad.

• Lists of stellar data can be custom tailored to meet the needs of the defense community.
• The star lists can be arranged to suit required wavelengths in the visible and infra-red.
• Problems with star positions can be caused by double stars, variable stars and known defects in catalogs. USNO can assist with resolving these problems.
• USNO maintains the international double star and orbit star databases.
• Observations can be made on short notice with USNO instruments.

• For those organizations needing the highest accuracy Earth orientation in inertial space
• Twice weekly e-mailed updates are available by emailing request to ser7@maia.usno.navy.mil
• Please see http://maia.usno.navy.mil/bulletin-a.html for daily updates.

• For those organizations requiring the GPS orbit ephemerides, earth orientation parameters, satellite clocks, tracking receiver clocks, and station coordinates.
• The highest accuracy information is available in Final form (11-day delay)
• Near real-time and real time application can use the daily Rapid (17-hour delay) predictions or the twice- daily Ultra-Rapid Predictions.
• Please see http://igscb.jpl.nasa.gov for additional information.

• For use by anyone wanting network timing from the World Wide Web.
• The service is free to clients.
• SIPRNET timing service is also available.
• The service is capable of 0.1 to 20 millisecond accuracy.
• Please e-mail Rich Schmidt at res@tuttle.usno.navy.mil for additional information.

• For use by those organizations which require their GPS receiver(s) to output UTC(USNO) as accurately as possible.
• To use the service, each user provided GPS receiver must have a 1 pulse per second input/output depending on model
• The service will provide either a report of the receiver's bias or a calibrated receiver (depending on the type of receiver and user requirements).
• The accuracy of the calibration is dependent of the receiver type.
• The service costs $1,000(US) per receiver shipped to USNO and takes 5 working days to complete. Any required travel is at cost.
• Note: This service should be performed on at regularly scheduled intervals to maintain the accuracy.
• Please e-mail Mihran Miranian at miranian.mihran@usno.navy.mil for additional information.

• For use by those organizations which require (desire) their clocks to be synchronized to UTC(USNO).
• To use the service, the user's timing site must have a 1 pulse per second signal point, which will become the on-time calibrated point.
• The accuracy of the calibration depends on the stability of the signal provided.
• The service costs $1,000(US) plus travel expense. The time synchronization requires 24-hours to perform. Five calendar days are required to determine the local clock rate (frequency).
• Note: This service should be performed on at regularly scheduled intervals to maintain the accuracy.
• Please e-mail Mihran Miranian at miranian.mihran@usno.navy.mil for additional information.

• For use by those organizations which require the highest time precision (accuracy < 10 nanoseconds) or have a requirement for an alternative method (to GPS) of recovering precise time.
• The service provides time precision of 300 picoseconds with an accuracy of 1 nanosecond.
• The service costs $50,000(US) per year. The ongoing maintenance costs are included in the cost of the service. Minimal customer time is required for the operation of the service.
• Please e-mail Paul Wheeler at wheeler.paul@usno.navy.mil for additional information.