Review of electronic systems for remote sensing and ranging

Problems with regard to primary and secondary radar sensors in military and civil applications are discussed, considering the use of very high frequencies (beyond 30 GHz) and the defense of ships under attack from low-flying aircraft. Systems used to counter the effects of rain clutter and electronic countermeasures are mentioned, with attention given to adaptive polarization and chaff. The development of infrared ray sensor technology is considered, as are laser sensors and their use in measuring the migration speed of microorganisms. Also discussed is the medical use of ultrasonic devices in the megahertz frequency range.