Negev Topography Mapped by Endeavour Shuttle

The Endeavour Shuttle craft launched last Friday from Cape Canaveral will be aided by researchers of Ben-Gurion University of the Negev to produce a precise topographical mapping of the Negev desert. According to Dr. Dan Blumberg of the BGU Department of Geography and Environmental Development, the improved 3-D images of the earth’s surface to be obtained by Endeavour should have an impact on many fields. Precise knowledge of height variations on land can be used to improve weather forecasting, record earth movements associated with earthquakes, or simply to update the maps used by authorities for planning the location of roads, bridges and buildings.

Blumberg, an expert in remote sensing, explains: Because of the cost and impracticably long times required for standard topographical mapping from aircraft and ground surveying, most of the planet’s surface has still to be mapped in 3-D. With the state-of-the-art radar interferometry equipment carried aboard Endeavour, mapping of 80 percent of the earth’s surface will be completed in only 11 days. This is undoubtedly one of the most important missions ever performed by NASA. Of particular interest to this mission are deserts, because although they cover some 40 percent of the earth’s surface, most of them have never been accurately mapped. The information expected from the Endeavour and subsequent radar missions will enhance our knowledge of the size of deserts, their expansion, and the movement of sand dunes, factors that are essential for understanding and preserving the ecology of arid and semi-arid regions.

In this project, Dr. Blumberg – working with graduate students, including Shahar Solar and Moti Raz – has positioned some 13 specially constructed radar-corner reflectors screen devices made of aluminum at different locales in the Negev. Using differential GPS surveying – the most accurate available today – precise longitudes and latitudes of the reflectors are measured by the team. When the Endeavour passes over the region, these reflectors will be easily observed, providing calibration points to ensure that the mapping data is accurate.

Under contract from the German Space Agency, one of the supporters of the Shuttle Radar Topography Mission, Dr. Blumberg expects to clarify an important aspect of the radar mapping of deserts. Although radar will reflect off metal, just as light reflects off a mirror, it is not at all apparent that when reflecting off sand, the radar does not penetrate some centimeters into the sand before bouncing back.

Because of the precision of radar mapping, researchers can compare the height of the calibration point with the height determined by the reflection a few meters away. This gives the depth of penetration into sand, further improving mapping accuracy. The BGU Blumberg group will later analyze the high-definition data from the five scheduled passes over the Negev by Endeavour. For more information, on the latest GPS News see gps maps.

Author Notes:

Rudy Douval contributes and publishes news editorial to http://www.handheld-gps-reviews.com.  A wealth of information about Global Positioning Systems for commercial or personal use.