This data set includes differential range delay data, and electron content samples of the intervening solar corona between Ulysses and Earth, at ten-minute intervals from the Ulysses Solar Corona Experiment (SCE) during the first solar conjunction (C1) of the Ulysses mission in the interval of August 7 to September 5, 1991. SCE uses a dual-frequency radio-sounding technique to exploit the dispersive nature of ionized media on the propagation of the two downlinks. The tiny doppler shift due to plasma moving in and out of the ray path is greater at S-band than at the higher frequency X-band. Similarly, because the group velocity of waves propagating in ionized media is smaller for lower frequencies, the round-trip time of propagation for coded range signals between the spacecraft and the ground station is longer in the S-band than in the X-band.
For the C1 solar conjunction the received frequencies at S-band and X-band were recorded at a nominal sample time of one per second, and differential range delay data were recorded nominally at intervals of about 10 minutes. These telemetry data are archived at JPL in raw form on Archival Tracking Data Files (ATDF's) after downlink through the NASA Deep Space Network (DSN) and intermediate processing, after which the total electron content (TEC) of the intervening coronal region between Ulysses and the Earth is determined by extraction of the ranging data from the ATDF files for further processing. The ATDF files also include doppler ranging data which are not included in this data set.
All fully processed ranging data during the Ulysses C1 solar conjunction have been provided in the RANGE_C1.TAB ascii file. This file contains recorded and calculated parameters for date, time (UT - ground received), run and tracking station number, differential range delay in range units (RU), and total or columnar electron content (TEC) in units of hexems (10**16 e/sq-mt). Accuracy of the range delay measurement is of order 50 RU. Further details of the data processing are given in the SCE_DS_C1.TXT documentation file and the references therein. Details on the SCE experiment are available in Bird, M. K., et al., The Coronal Sounding Experiment, Astron. and Astrophys. Supp. Ser., 92 (2), 425-430, 1992.