Distance estimation using multiple phase differences
A system, method, and computer program product are provided for estimating a distance to an object. The system includes a transmitter for transmitting RF signals from a location of an object. The system further includes measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals. The system also includes a processor. The processor is configured to calculate corrected phases by resolving one or more ambiguities from the plurality of phase differences. The processor is further configured to obtain a characteristic curve using the corrected phases. The processor is also configured to provide an estimate of the distance based on the characteristic curve and the corrected phases.
1. A system for estimating a distance to an object, comprising:
a transmitter for transmitting RF signals from a location of an object;
measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals;
a processor configured to
calculate corrected phases by resolving one or more ambiguities from the plurality of phase differences;
obtain a characteristic curve using the corrected phases; and
provide an estimate of the distance based on the characteristic curve and the corrected phases;
wherein a given one of the corrected phases is calculated by adding an integer multiple of an ambiguity factor to a given normalized phase to resolve the one or more ambiguities of the given normalized phase, the given normalized phase calculated from at least one of the plurality of phase differences; and
wherein the ambiguity factor is equal to 2π.
2. A system for estimating a distance to an object, comprising:
a transmitter for transmitting RF signals from a location of an object;
measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals;
a processor configured to
calculate corrected phases by resolving one or more ambiguities from the plurality of phase differences;
obtain a characteristic curve using the corrected phases; and
provide an estimate of the distance based on the characteristic curve and the corrected phases;
wherein a given one of the corrected phases is calculated by adding an integer multiple of an ambiguity factor to a given normalized phase to resolve the one or more ambiguities of the given normalized phase, the given normalized phase calculated from at least one of the plurality of phase differences; and
wherein the ambiguity factor is equal to π.
3. A system for estimating a distance to an object, comprising:
a transmitter for transmitting RF signals from a location of an object;
measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals;
a processor configured to
calculate corrected phases by resolving one or more ambiguities from the plurality of phase differences;
obtain a characteristic curve using the corrected phases; and
provide an estimate of the distance based on the characteristic curve and the corrected phases;
wherein the transmitted RF signals are transmitted using a plurality of wavelengths, and wherein the characteristic curve, at least one of the plurality of wavelengths, and a normalized phase calculated from at least one of the plurality of phase differences provide the estimate for the distance.
4. The system of claim 3 , wherein a slope of the characteristic curve, the at least one of the plurality of wavelengths, and the normalized phase provide the estimate for the distance.