Adaptive hybrid tracking algorithms for radio signal parameters estimations

A method for tracking carrier-to-noise ratio (C/N0) and a phase correction (Δϕ) of a reflected radio frequency (RF) carrier signal, comprising:

• receiving a digital direct line-of-sight (DLOS) intermediate frequency (IF) signal of a DLOS component of an RF carrier signal transmitted by a transmitter located above the surface of the earth and a digital reflected IF signal of a reflected component of the carrier signal that is reflected from a specular point (SP) on the surface of the earth;
• generating modeled reference signal parameters using the digital DLOS IF signal and known locations of one or more receiving antennas, the transmitter, and the SP;
• generating a reference signal based on the modeled reference signal parameters and feedback of a previously estimated Δϕ;
• correlating the reference signal with the digital reflected IF signal to produce in-phase (I) and quadrature-phase (Q) correlation results;
• and
• calculating an estimated C/N0 and an estimated Δϕ for the digital reflected IF signal from the correlation results.

A computer program product, comprising a non-transitory and tangible computer-readable storage medium whose contents include a program with instructions being executed on a processor to perform a method for tracking a carrier-to-noise ratio (C/N0) and a phase correction (Δϕ) of a reflected radio frequency (RF) carrier signal, the method comprising:

• providing a system, wherein the system comprises one or more distinct software modules, and wherein the distinct software modules comprise a signal parameter modeling module, a reference generator, a correlator, and an estimator;
• receiving a digital direct line-of-sight (DLOS) intermediate frequency (IF) signal of a DLOS component of an RF carrier signal transmitted by a transmitter located above the surface of the earth and a digital reflected IF signal of a reflected component of the carrier signal that is reflected from a specular point (SP) on the surface of the earth using the signal parameter modeling module;
• generating modeled reference signal parameters using the digital DLOS IF signal and known locations of one or more receiving antennas, the transmitter, and the SP using the signal parameter modeling module;
• generating a reference signal based on the modeled reference signal parameters and feedback of a previously estimated Δϕ using the reference generator;
• correlating the reference signal with the digital reflected IF signal to produce in-phase (I) and quadrature-phase (Q) correlation results using the correlator;
• and
• calculating an estimated C/N0 and an estimated Δϕ for the digital reflected IF signal from the correlation results using the estimator.