Dual target tracking altimeter

A method for modifying a conventional altimeter to be operable to determine a first distance and a second distance from an aircraft, wherein the first distance represents distance from the aircraft to a first target and the second distance represents distance from the aircraft to a second target, wherein the conventional altimeter includes at least an IF strip, a first amplifier, an altimeter processor, and a first filter, and wherein the conventional altimeter is operable to determine the first distance, the method comprising in combination:

• providing a second amplifier operable to amplify a return signal from the IF strip, wherein the return signal includes a first return and a second return, wherein the first return is received at a first return time and includes a first leading edge corresponding to a pulse signal hitting the first target, and wherein the second return is received at a second return time and includes a second leading edge corresponding to the pulse signal hitting the second target;
• providing an analog-to-digital converter operable to sample the return signal;
• providing a memory unit operable to store the sampled return signal;
• providing an integrator operable to integrate at least a portion of the plurality of sample pulses to improve signal-to-noise ratio;
• providing a waveform analysis unit operable to determine the second distance by determining at least one difference among the first return time, the second return time, and a send time corresponding to the pulse signal being transmitted from the aircraft;
• providing a second filter;
• and
• providing a timing control unit.