Base-line calibrations of the Mini-Ranger III and the role of signal strength in correcting real-time hydrographic position data.

Abstract

Five base-line calibrations of the Motorola Mini-Ranger III (MRS III) shortwave positioning system were performed across Puget Sound, Washington, in January 1984. Two MRS III codes were calibrated over measured distances of 1061.2, 2417.5, 4083.1, 7016.8, and 9861.1 meters. Reference lengths were obtained to submeter accuracy using a Tellurometer , Model CA-1000. Results of the data analysis suggest that an optimum base-line length of about 2,500 meters provides a characteristic calibration curve that adequately depicts all equipment configurations for a typical MRS III. The calibration curve was best characterized by high-gain antenna data for two Mini-Ranger codes. The high-gain antenna also exhibited the least sample deviation of the three antenna types calibrated. Range average was found to be insignificant. Regression curves applied to the data showed no change in quality of fit above a power of three and variances of 0.5 meters indicated a fair to good fit of the data.