FMCW RADAR WITH REFINED MEASURMENT USING FIXED FREQUENCIES

摘要

One embodiment is directed to a method for operating a radar altimeter. The method includes transmitting a radar signal at a first frequency, ramping the frequency of the radar signal from the first frequency to a second frequency, and transmitting the radar signal at the second frequency. The reflections can be processed by determining an approximate distance to a target based reflections of the frequency ramp and the approximate distance can be refined based on a phase difference between a reflection of the radar signal transmitted at the first frequency and a reflection of the radar signal transmitted at the second frequency.

主权项

1. A method for operating a radar altimeter, the method comprising:
transmitting a radar signal at a first frequency for a first length of time; ramping the frequency of the radar signal from the first frequency to a second frequency; transmitting the radar signal at the second frequency for a second length of time; receiving reflections of the radar signal; processing the reflections by:
determining an approximate distance to a target from which the reflections are received based on an amount of time between transmission of the radar signal having the frequency ramp and reception of a reflection of the radar signal having the frequency ramp;determining a first phase of a reflection of the radar signal transmitted at the first frequency, wherein the first phase is the phase of the radar signal as received;determining a second phase of a reflection of the radar signal transmitted at the second frequency, wherein the second phase is the phase of the radar signal as received;calculating a phase difference between the first phase and the second phase; andrefining the approximate distance to the target based on the phase difference between the first phase and the second phase.