Improved geodetic results from camera observations of satellites

Analysis of Baker Nunn camera observations of satellites 1959α1 over 1032 days; 1959η over 792 days; 1960t2 over 480 days; 1961δ1 over 150 clays; and 1961αδ1 over 54 days yielded results greatly improved over those previously reported. This improvement is primarily due to the use of much more data and secondarily to various modifications in the method of analysis. As indicated by the discrepancies between results from appreciably different orbits, the datum shifts obtained have standard deviations of ±4 to ±23 meters. The tesseral harmonic of the gravity field most firmly determined appears to be J11, followed by J22, J31, J42, J13, and J32. The principal sources of error suggested are the influence of preassigned variances on separation of gravitational coefficients having the same periodic effects on an orbit (e.g., J22 and J42) and the holding fixed with respect to each other stations on the same geodetic datum, but they do not seem adequate to explain all systematic discrepancies in the results. A comparison of gravitational and geometric geoid heights at station positions gave a mean equatorial radius of 6,378,196±11 meters.