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Diagram showing how orbit-determination data was handled in a 1962 NASA mission. (Of historical interest only.)
Orbit determination is the estimation of orbits of objects such as moons, planets, and spacecraft. One major application is to allow tracking newly observed asteroids and verify that they have not been previously discovered. The basic methods were discovered in the 17th century and have been continuously refined.
Observations are the raw data fed into orbit determination algorithms. Observations made by a ground-based observer typically consist of time-tagged azimuth, elevation, range, and/or range rate values. Telescopes or radar apparatus are used, because naked-eye observations are inadequate for precise orbit determination. With more or better observations, the accuracy of the orbit determination process also improves, and fewer "false alarms" result.
After orbits are determined, mathematical propagation techniques can be used to predict the future positions of orbiting objects. As time goes by, the actual path of an orbiting object tends to diverge from the predicted path (especially if the object is subject to difficult-to-predict perturbations such as atmospheric drag), and a new orbit determination using new observations serves to re-calibrate knowledge of the orbit.
Satellite tracking is another major application. For the US and partner countries, to the extent that optical and radar resources allow, the Joint Space Operations Center gathers observations of all objects in Earth orbit. The observations are used in new orbit determination calculations that maintain the overall accuracy of the satellite catalog. Collision avoidance calculations may use this data to calculate the probability that one orbiting object will collide with another. A satellite's operator may decide to adjust the orbit, if the risk of collision in the present orbit is unacceptable. (It is not possible to adjust the orbit for events of very low probability; it would soon use up the propellant the satellite carries for orbital station-keeping.) Other countries, including Russia and China, have similar tracking assets.
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Orbitdetermination is the estimation of orbits of objects such as moons, planets, and spacecraft. One major application is to allow tracking newly observed...
and declination), to find the six orbital elements that completely describe an orbit. The theory of orbitdetermination has subsequently been developed...
they coincide with the actual orbit only at that moment. ECEF Earth-centered inertial Orbital plane Orbitdetermination State vector (navigation) Radial...
An areostationary orbit, areosynchronous equatorial orbit (AEO), or Mars geostationary orbit is a circular areosynchronous orbit (ASO) approximately...
precise positions in real-time with a support of orbit and clock corrections. Orbitdetermination of low-orbiting satellites with GPS receiver installed on board...
space station which Artemis program participants plan to assemble in an orbit near the Moon. The Gateway is intended to serve as a communication hub,...
has been used to perform professional astronomy research, such as orbitdetermination of small Solar System bodies in the early 1900s and supernova surveys...
is now visible again (also see lost minor planet and lost comet). Orbitdetermination requires measuring an object's position on multiple occasions. The...
The presence of the GPS signal in space also makes it suitable for orbitdetermination and satellite-to-satellite tracking. Examples: GPS, GLONASS, Galileo...
near-Earth asteroids (inside the orbit of Mars). The process of orbitdetermination is conceptually the same in both cases. First students take a series...
ocean and atmospheric systems. In addition, SLR provides precise orbitdetermination for spaceborne radar altimeter missions mapping the ocean surface...
orbit, and it has the magnitude of orbital eccentricity. This makes it very useful in orbitdetermination (OD) for the orbital elements of an orbit when...
computing. In 1964, an early version of TRACE, a high-precision orbitdetermination and orbit propagation program, was used on an IBM 7090 computer. Operation...
of its orbit which is generally based on a short observation arc of less than 2 weeks. Follow-up observations to improve the orbitdetermination Calculating...
Boulder. He is known for his work in satellite navigation and precise orbitdetermination. He worked on various missions while at the Jet Propulsion Laboratory...
evaluate the Manned Space Flight Network tracking stations and Apollo OrbitDetermination Program. The spacecraft was placed in a cislunar trajectory and on...
satellites.) Other satellites include retroreflectors for orbit calibration and orbitdetermination, such as in satellite navigation (e.g., all Galileo satellites...
because the available observational data is insufficient for reliable orbitdetermination. With limited information astronomers cannot know where to look for...
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