Laser air data system using enhanced-mode lidar

摘要

This paper reports the test results for a three-axis true airspeed measurement instrument that is based on the enhanced mode lidar (EML) concept. This instrument is a continuing Goodrich development effort that builds on the single-axis homodyne concept. Our system heterodynes a reference signal with the single particle lidar return from naturally occurring atmospheric aerosols. The reference signal's frequency is shifted by an acousto-optic modulator, thereby, enabling the measurement of the positive and negative Doppler frequencies. A scan head using a wedge to direct the beam at a 15-degree angle is rotated about the original line of site to trace a cone shape. The redirected beam plus the heterodyning enables the measurement of three-axis true airspeed. The instrument was evaluated using wind tunnel measurements and the results are reported.