Analysis of Lidar Remote Sensing Concepts

Abstract

An orbiting coherent Doppler lidar for measuring winds is required to provide two basic pieces of data to the user community. The first is the line of sight wind velocity and the second is knowledge of the position at which the measurement was made. In order to obtain this data for targets of interest to the atmospheric community the instrument must also have a level of backscatter sensitivity sufficient to achieve the goal. Sensitivity analyses for the line of sight velocity and position requirements for two lidar instruments, one with a nadir angle of 30 deg. in a 300 km altitude, 58 deg. inclination orbit and the second for a 45 deg. nadir angle instrument in a 833 km altitude , 89 deg. inclination orbit are performed. The issues relating to the backscatter sensitivity of a coherent lidar have been well documented previously and are not discussed here other than to identify a space-specific issue that does not typically need to be considered for ground and aircraft based coherent lidars. Section 2 and appendices A1 and A2 document these sensitivity analyses. This contract was intended to develop requirements for a space shuttle (STS) based coherent lidar however, shortly after the award of this contract NASA MSFC won the SPARCLE program to put a coherent Doppler lidar on STS. Consequently much of the work conducted under this contract has been documented within the development of the SPARCLE project documentation. The relevant portions of the SPARCLE documentation are identified in section 3.0 and included in appendices A3 and A4. Section 4.0 briefly outlines miscellaneous other activities that occurred under this contract.