Abstract

The laser true airspeed system (LATAS) developed by RSRE and RAE Bedford has now been flown in the HS 125 aircraft for nearly four years. The equipment incorporates a 4W waveguide laser and 25 MHz bandwidth surface acoustic wave spectrum analyser and has been described in earlier publications. An extensive flight program has investigated not only the measurement of true airspeed ahead of the aircraft but also pressure error measurement and wind shear and turbulence. From the strength of the doppler return the back scattering strength in the atmosphere at 10.6μm can be obtained. The most recent calibration analysis shows that the limiting sensitivity corresponds to 3 times 10 to the minus 11 per M per SR. During the flight program at altitudes to 13.1 km a body of data over Northern Europe and the UK at different seasons of the year and in different conditions has been accummulated and also in mid summer in Colorado during 1982 JAWS exercise.

© 1985 Optical Society of America