Patent ID: 7548181

Claim:
An earth penetrating radar, comprising: a software-defined transceiver (SDT) programmed as a geologic-media penetrating radar with multi-channel direct digital synthesizer (DDS) for synthesizing many coherent first and second frequency continuous waves ω H1 ,ω L1 , ω H2 ,ω L2 , etc., as individual pairs and each member of a separated from the other member in the pair in frequency by n-MHz, m-MHz, etc.; a feedback enabled pre-distorter for dynamically predistorting each of said pairs of first and second frequency continuous waves to account for non-linearities in following stages and antennas; a power amplifier and antenna for launching corrected versions of said coherent pairs of said first and second frequency continuous waves into the earth and a first interface; a receiver and antenna for collecting a relatively strong signal reflected from said first interface and substantially weaker signals reflected from deeper buried objects and interfaces of material with contrasting dielectric constants; a down-converter and demodulator disposed in the SDT and for demodulating in-phase, I=sin(ω m τ 1 )sin(ω c τ 1 )+sin(ω m τ 2 )sin(ω c τ 2 ), and quadrature-phase Q=sin(ω m τ 1 )cos(ω c τ 1 )+sin(ω m τ 2 )cos(ω c τ 2 ) signals for each pair of transmitted first and second frequency continuous waves, wherein ω m represents a modulation frequency, ω c represents a virtual carrier frequency, τ 1 represents the echo delay time occurring for reflections from said first interface near the antenna, and τ 2 represents the echo delay time occurring for more distant reflections from buried objects and interfaces; and a computer and display for showing a user the depth of said buried objects and interfaces by simultaneously solving for all echo delay times τ 2 for each differently separated pair of first and second frequencies; wherein, echo delay time τ 1 is near zero and near reflection surface terms including it are manipulated by a configuration of constituent parts to zero out in the step of computing and displaying.