The orbit of Ariel 4 (1971  109A)
Abstract
The definitive orbit of Ariel 4 was computed, from Minitrack observations, for the two periods during which orbital parameters were required for use in telemetry analysis  from December 1971 (launch) to May 1973, and from October to December 1973. The orbit was represented by a model with eight independent orbital parameters, and the values of these parameters were determined, and are listed, at threeday intervals. The accuracy was much the same for all the determinations, being about 0.000004 in eccentricity and 2 in. for the angular parameters; this would correspond to a nominal position accuracy of about 120 m in using the orbital parameters, though the actual errors may have approached 500 m at times, arising from perturbations due to unmodelled tesseral harmonics.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 July 1975
 Bibcode:
 1975STIN...7624304G
 Keywords:

 Accuracy;
 Ariel 4 Satellite;
 Orbit Calculation;
 Orbit Perturbation;
 Correlation;
 Eccentricity;
 Orbital Elements;
 Periodic Variations;
 Tesseral Harmonics;
 Astrodynamics