ABSTRACT
The essential feature of a RASS system is that it has an acoustic transmitter and a RADAR transmitter-receiver. The electromagnetic (EM) energy is reflected by the periodic refractive index variations created by the compressions and expansions of the air within the acoustic pulse. The RADAR wavelength is chosen to be half the acoustic wavelength so that EM reflections from successive acoustic compressions will combine in phase, giving a strong RADAR signal. By monitoring the acoustic properties, the speed of sound is deduced and hence the temperature.
