Sensitivity and resolution comparisons for remote sounding methods

Design of the sounding waveform is an important consideration in both remote sounding of environmental targets and characterization of communication channels since it is this waveform that determines, to a large extent, the sensitivity and resolution capabilities of the sounder. It is highly desirable to be able to compare the different possible waveforms and sounding techniques with regard to sensitivity or output signal-to-noise ratio, and resolution in time delay and frequency shift. A straight-forward quantitative method of comparing the sensitivity of dissimilar sounders is developed and illustrated by an example comparing a microwave sounder and an acoustic sounder. The comparison of resolution capability is made by using the ambiguity function or delay-doppler weighting function for that waveform. This presentation covers properties of the ambiguity function and examples for the four principle types of sounder waveforms; pulse, coherent pulse sequence, linear FM and coded. A distinct advantage to these comparison methods is that they are easy to apply and can be used in the planning stage of a project since neither experimental results nor detailed design data are needed. The presentation is directed to scientists and engineers not familiar with recent developments in radar.