Rover Data Research Articles

Rocky 7 prototype Mars rover field geology experiments: 1. Lavic Lake and Sunshine Volcanic Field, California

Experiments with the Rocky 7 rover were performed in the Mojave Desert to better understand how to conduct rover‐based, long‐distance (kilometers) geological traverses on Mars. The rover was equipped with stereo imaging systems for remote sensing science and hazard avoidance and 57Fe Mössbauer and nuclear magnetic resonance spectrometers for in situ determination of mineralogy of unprepared rock and soil surfaces. Laboratory data were also obtained using the spectrometers and an X ray diffraction (XRD)/XRF instrument for unprepared samples collected from the rover sites. Simulated orbital and descent image data assembled for the test sites were found to be critical for assessing the geologic setting, formulating hypotheses to be tested with rover observations, planning traverses, locating the rover, and providing a regional context for interpretation of rover‐based observations. Analyses of remote sensing and in situ observations acquired by the rover confirmed inferences made from orbital and simulated descent images that the Sunshine Volcanic Field is composed of basalt flows. Rover data confirmed the idea that Lavic Lake is a recharge playa and that an alluvial fan composed of sediments with felsic compositions has prograded onto the playa. Rover‐based discoveries include the inference that the basalt flows are mantled with aeolian sediment and covered with a dense pavement of varnished basalt cobbles. Results demonstrate that the combination of rover remote sensing and in situ analytical observations will significantly increase our understanding of Mars and provide key connecting links between orbital and descent data and analyses of returned samples.

ASSEMBLING A REAL-TIME DGPS—TESTING AND INVESTIGATING FACTORS THAT AFFECT ITS ACCURACY

A real-time differentially corrected global positioning system (RDGPS) was assembled and tested in the field.The RDGPS was assembled using two GPS receivers and two radios. One receiver was utilized as a base station receiverand its antenna was fixed at a benchmark, while the other was used as a mobile receiver (rover). RDGPS accuracy wastested by collecting position data from the rover and comparing it to a previously determined position of a point in thefield. The effect of imprecise position determination of base station benchmark on the RDGPS accuracy was investigated.Moreover, the effect of the age of differential correction messages on position determination accuracy produced by therover was revealed. The RDGPS maintained an average accuracy of less than one meter. The average positiondetermination error produced by the rover was almost equal to and in the opposite direction of the error in base stationbenchmark coordinates. Seventy-two percent of the tested rover data maintained an accuracy of less than 3 m with acorrection message age of less than 29 s. However, location determination error of the rover reached up to 30.84 m with acorrection message age of 98 s.