Radar Level Measurement Basics

Pulse radar has been used widely for distance measurement since the very beginnings of radar technology. The basic form of pulse radar is a pure time of flight measurement. Short pulses, typically of millisecond or nanosecond duration, are transmitted and the transit time to and from the target is measured. The pulses of a pulse radar are not discrete monopulses with a single peak of electromagnetic energy, but are in fact a short wave packet (Fig. 13). The number of waves and the length of the pulse depend upon the pulse duration and the carrier frequency used. These regularly repeating pulses have a relatively long time delay between them to allow the return echo to be received before the next pulse is transmitted.