Performance comparison of model options. Peak errors in 14-day prediction arcs following a two-day orbit determination have been evaluated for eight test dates spread over a three-month period. Median and maximum errors over the tests are provided for various forms of simplifications relative to a comprehensive reference along with the approximate reduction in computational load. Models marked by a × symbol are recommended for use in the long-term propagator
| Model | Recommended | Option | Peak error median/max [m] | Runtime reduction [%] |
|---|---|---|---|---|
| Nutation | IAU980 (106 terms) | (ref) | ||
| × | 49 terms > 0.0005″ | 3.4 / 21 | –1 | |
| 18 terms > 0.005″ | 23/85 | –2 | ||
| EOPs | Observed | (ref) | ||
| × | Extrapolated | 34/59 | –2 | |
| Earth gravity | 12 × 12 model | (ref) | ||
| 10 × 10 model | 0.1 / 0.1 | –4 | ||
| × | 9 ×9 model | 0.3 / 0.3 | –5 | |
| Relativity | Schwarzschild correction | (ref) | ||
| × | neglected | 2.6/7.8 | –1 | |
| Tides | Solid Earth | (ref) | ||
| × | k2 tide | 0.5 / 2.4 | –5 | |
| none | 34 / 74 | –8 | ||
| Sun position | full series | (ref) | ||
| × | terms > 5″ | 3.7 / 5.0 | –4 | |
| Keplerian | 13/29 | –11 | ||
| Moon position | full series | (ref) | ||
| × | terms > 2″ | 6.1 / 47 | –7 | |
| terms > 10″ | 39 / 260 | –8 | ||
| Recommended (×) | 32/62 | –25 |