System and method for measuring distance

A method of measuring range to a target, comprising:

• reflecting electromagnetic energy from the target;
• sensing the intensity of the target reflected electromagnetic energy at first and second locations spaced apart a predetermined distance in target range, said first and second locations being substantially in colinear alignment with the point on the target from which the energy is reflected;
• generating a difference signal the magnitude of which is a function of the difference between the magnitudes of the intensity of the target reflected energy at said first and second locations;
• and,
• generating a quotient signal the magnitude of which is proportional to the magnitude of the intensity of the target reflected energy at said first location divided by the magnitude of said difference signal whereby said quotient signal is a known function and hence a measure of target range.

A method of measuring range to a target, comprising:

• reflecting electromagnetic energy from the target;
• sensing the intensity of the target reflected electromagnetic energy at first and second locations spaced apart a predetermined distance in target range, said first and second locations being substantially in colinear alignment with the point on the target from which the energy is reflected;
• generating a difference signal the magnitude of which is a function of the difference between the magnitudes of the intensity of the target reflected energy at said first and second locations, the magnitude of said difference signal being equal to the one of said sensed intensities at said first and second locations which has the largest magnitude less a predetermined percent of the magnitude of the smaller of said sensed intensities;
• generating a quotient signal the magnitude of which is linearly proportional to the magnitude of the intensity of the target reflected energy at said first location divided by the magnitude of said difference signal whereby said quotient signal is a known function and hence a measure of target range;
• and,
• generating an output signal equal to the magnitude of said quotient signal raised to a selected power whereby the magnitude of said output signal is substantially linearly proportional to target range over a selected range of values of target range.