Signal processing in short-pulse geophysical radar system

Claim 1

In a geophysical radar system comprising: A. transmitting means for transmitting repetitive short radar pulses into the earth, B. receiving means for detecting reflected radar energy returned as the repetitive pulses are reflected from various discontinuities at various depths within the earth, and C. output means for providing an indication of the reflected radar energy in a form which is intelligible to a human observer, the improvement comprising: D. deriving means responsive to the detected radar energy for deriving a sequence of digital representations of the amplitude of the reflected energy as said reflected energy is detected by the receiving means at another corresponding sequence of instants in time, each of said instants occurring at individually selected amounts of time after each corresponding transmitted pulse is transmitted into substantially the same part of the earth, whereby the digital representations represent whatever discontinuities are present at corresponding depths into the earth, E. selecting means for selecting said individually selected amounts of time according to the attenuation suffered by reflected radar energy as received at the receiving means from said selected depths such that a greater plurality of said digital representations are derived for selected depths suffering greater attenuation than are derived for selected depths suffering lesser attenuation, and F. combining means for combining all of the sequence of digital representations formed at one depth at substantially one part of the earth to form a combined representation with improved signal-to-noise ratio.