| Abstract: | The spaceborne laser ranging (or lasering) system provides a method of precise positioning of a large number of points on the earth's surface in a short period of time. That is, a measure of the relative location of geodetic markers from a space platform can maintain horizontal and vertical control to 2–5 cm. At this level of control, small earth surface crustal motions should be detectable. Development of a model for the strain field can be constructed. Furthermore, the spaceborne lasering system can survey an area in a very short period of time (1–2 weeks) and resurvey the area as required.System design parameters are now being established by NASA for a possible test flight aboard the Shuttle in 1982. These include design specifications of economical corner cubes for ground retroreflectors, coupled with the evolution of engineering model to flight model development. If the experiment of the Shuttle proves successful, it is hoped to put the laser in a free flight satellite. This paper presents the results of a simulated analysis for this contingency.The system is conceived as an orbiting ranging device with a ground base grid of reflectors or transponders (spacing 1.0–30 km), which are projected to be of low cost (maintenance-free and unattended) and which will permit the saturation of a local area to obtain data useful in monitoring crustal movements. The test network includes 75 stations with roughly half of them situated on either side of the San Andreas fault. Critical study comparatively evaluates various observational schemes and statistically analyzes crustal motion recovery.The study considers laser radar as the main ranging system, pending final selection from many possible candidates. The satellite orbit is inclined at 110° and slightly eccentric (e = 0.04) with orbital altitudes varying from 370 to 930 km. |
