1. SBV MetricandPhotometricProcessing
2. Through this technique, the pointing of the SBV sensor is routinely established to the level of a few tenths of an arcsecond. In addition, pointing is determined independently for each data acquisition, or look, which avoids common problems such as the drift and random walk typically associated with gyroscopes. Once pointing is established, we use this information to map the end points of the streaks on the focal plane to absolute angular positions on the sky, thusproducinganobservation [10, 11]. state of the OPS constellation of satellites inthe late 1980s.)
3. While the process described above is sufficient to produce angular measurements on targets from a space-based sensor, it is insufficient for the complete incorporation of these data into a ground-based tracking network. To accomplish this integration of data we must be able to determine the position, or ephemeris, of the MSX at the time the data were gathered. As part of an independent processing pipeline, Lincoln Laboratory has maintained the ephemeris of the MSX to an accuracy of six meters, surpassing the original SBV Critical Design Review goal of fifteen meters. The determination of the ephemeris of the MSX is accomplished byprocessing S-band ranging data from the Space Ground Link System, a network of ground-based telemetry sensors used by the U.S. AirForce to track its space assets [12-14]. (A Global Positioning System [GPS] receiver was not integrated on the MSX because of weight constraints and because of the nascent15°