NASA Jet Propulsion Laboratory California Institute of Technology JPL HOME EARTH SOLAR SYSTEM STARS & GALAXIES SCIENCE & TECHNOLOGY BRING THE UNIVERSE TO YOU JPL Email News RSS Podcast Video


Background on the SAC-C Experiment

SAC-CIn the year 2000, the Argentinian satellite SAC-C was launched carrying a new generation of GPS receivers, the "Blackjack", developed at JPL. The mission is managed by the Argentinian CONAE, which will be the other main data processing center for SAC-C occultations. On July 7th. the SAC-C Blackjack captured its first profile and has since been collecting up to 250 daily occultations during much of 2001. This receiver has enhanced capabilities over the older generation GPS/MET instrument which include "enhanced codeless" tracking (i.e., the ability to track the encrypted GPS signals), higher signal-to-noise ratio, and lower tracking in the atmosphere. The Blackjack GPS receiver is capturing high vertical resolution profiles over land and oceans and is providing data complementary to other sounding techniques. From this point on, the amount of data is expected to increase with ongoing enhancements of the receiver's software.

JPL ftp server for SAC-C data 

Early Results from SAC-C


(a) Nearly coincident profiles from CHAMP and SAC-C and the corresponding profiles from semi-daily NCEP analyses interpolated to the heights, locations, and times of the GPS occultations.


(b) Map of the geometry of the CHAMP (at 45E) and SACC (at 50E) occultation shown shown in 1.a. The spread of the points indicates the drift of the tangent point during the occultation. The lines indicate the direction of the occultation links extended over 200 km. The CHAMP and SAC-C occultations are separated by 300 km and occurred on July 11, 2001 at 1600 and 1800 UTC, respectively. )