FPGA based Variable Scan Rate Generic Stepper Motor Drive Algorithm for mm-Wave Sounder Payloads

Millimeter-wave Sounder Payloads provide vertical temperature and humidity profile of the earth's atmosphere. They contain reflector-mounted scan mechanism for providing a cross track swath coverage. This rotational motion facilitates a continuous swath of over 1000 kms and in-situ on-board calibration as the reflector looks at earth, deep space and blackbody at different positions of rotation. This paper presents and discusses a variable rate motor drive control algorithm for the Stepper motor of Scan mechanism. The scan motor drive algorithm is implemented on a FPGA based Payload Controller (PLC), which also implements the control and status monitoring functionality of sounder payload.