Tank Multi-Level Measurement Using Through the Air Millimeter Wave Radar

A tank level instrument for measuring a distance from near a top of a tank to one or more fluids in the tank, comprising:

• a chirp generator operable to generate a millimeter wave chirp that ramps linearly from a starting frequency to a higher frequency within a specified time span;
• a transmit antenna configured to transmit the chirp generated by the chirp generator into the tank;
• a receive antenna configured to receive one or more chirp reflections from the tank,
• a mixer operable to mix the chirp transmitted by the transmit antenna with the chirp reflections received by the receive antenna to generate one or more intermediate frequency signals;
• a processing unit operable to process the one or more intermediate frequency signals and derive one or more distances from the one or more intermediate frequency signals, each distance representing the distance from near the top of the tank to one of the one or more fluids in the tank or an obstruction in the tank;
• and
• a computer operable to automatically select intermediate frequency signals having a signal strength above a predefined minimum or distances within a predefined distance window for further processing and ignore other intermediate frequency signals and distances.