Engineering topics

Owen, William M., Jr.

Publications and source records attributed to Owen, William M., Jr..

5 records

NASA NTRS2012

Optical Navigation Preparations for New Horizons Pluto Flyby

The New Horizons spacecraft will encounter Pluto and its satellites in July 2015. As was the case for the Voyager encounters with Jupiter, Saturn, Uranus and Neptune, mission success will depend heavily on accurate spacecraft navigation, and accurate navigation will be impossible without the use of pictures of the Pluto system taken by the onboard cameras. We describe the preparations made by the New Horizons optical navigators: picture planning, image processing algorithms, software development and testing, and results from in-flight imaging.

image processing↗

NASA NTRS2011

Ground Optical Navigation for the Stardust-Next Mission to Comet 9P/TEMPEL1

Ground-based optical navigation (OpNav) using pictures taken by the Naviga-tion camera on the Stardust spacecraft provided the target-relative information needed to design maneuvers during its approach to comet Tempel 1. Hardware problems, limited downlink bandwidth, and changes in the flight profile affected the OpNav picture schedule, sometimes in near-real time. The Stardust naviga-tion camera and attitude control presented challenges. Picture-processing techniques were developed during approach that included background estimation, co-addition, and co-registration. These techniques, along with adaptive picture scheduling, successfully addressed the challenges.

9P/Temple 1↗

NASA NTRS2011

Methods of Optical Navigation

Optical navigation is the use of onboard imaging to aid in the determination of the spacecraft trajectory and of the targets' ephemerides. Opnav techniques provide a direct measurement of the direction from a spacecraft to target bodies. Opnav data thus complement both radiometric tracking data (for instance, Doppler and range) and the groundbased astrometry which is used to determine the a priori ephemeris of the targets. We present the geometry and camera models which form the mathematical basis for optical navigation and some of the image processing techniques by which one can extract the optical observables--that is, the sample and line coordinates of images--from pictures.

spacecraft navigation↗

NASA NTRS2003

Interplanetary optical navigation 101

The JPL Navigation and Mission Design Section has two related tasks: Mission Design: calculate a nominal trajectory which meets the diverse needs of the scientists on a particular mission. Locate deterministic maneuvers required to fly the nominal trajectory, while locating statistical maneuvers which correct errors in the actual trajectory. Navigation estimates the flight path of a spacecraft (orbit determination) using three fundamental data sets: ground based astrometric data; radio metric tracking data (Doppler, range).

mission design↗

NASA NTRS2000

Error Sources in Asteroid Astrometry

Asteroid astrometry, like any other scientific measurement process, is subject to both random and systematic errors, not all of which are under the observer's control. To design an astrometric observing program or to improve an existing one requires knowledge of the various sources of error, how different errors affect one's results, and how various errors may be minimized by careful observation or data reduction techniques.

Owen, William M., Jr.↗