Abstract: DLOS and reflected signal components of an RF carrier signal are received. The reflected component is reflected from a point on the surface of the earth. The DLOS and reflected components are converted to digital DLOS IF and reflected IF signals, respectively. Modeled parameters are generated using the digital DLOS IF signal and locations of one or more antennas, the transmitter, and the point. A reference signal is generated based on the modeled parameters. The reference signal is correlated with the digital reflected IF signal to produce in-phase and quadrature-phase correlation results. A C/N0 and an estimated phase (EP) are calculated for the digital reflected IF signal from the correlation results. A KF is applied to the EP to produce an estimated filter phase (EFP). The KF is adapted to filter the EP using the estimated C/N0 to reduce cycle slips and noise in the EFP.

Abstract: 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 are received. Modeled reference signal parameters are generated using the digital DLOS IF signal and known locations of one or more receiving antennas, the transmitter, and the SP. A reference signal is generated based on the modeled reference signal parameters and feedback of a previously estimated ??. The reference signal is correlated with the digital reflected IF signal to produce in-phase (I) and quadrature-phase (Q) correlation results. An estimated C/N0 and an estimated ?? for the digital reflected IF signal are calculated from the correlation results.

Abstract: A direct line-of-sight (DLOS) radio frequency (RF) signal component and a reflected RF signal component of an RF carrier signal are received from a transmitter. The reflected component is reflected from a point on the surface of the earth. The DLOS component is converted to a digital DLOS intermediate frequency (IF) signal and the reflected component that is converted to a digital reflected IF signal. Modeled reference signal parameters are generated using the digital DLOS IF signal and known locations of the one or more antennas, the transmitter, and the point. A reference signal is generated based on the modeled reference signal parameters and feedback of a previously estimated phase correction (??). The reference signal is correlated with the digital reflected IF signal to produce in-phase and quadrature-phase correlation results. Estimated carrier-to-noise ratio (C/N0) and ?? values are calculated for the digital reflected IF signal from the correlation results.

Abstract: A direct line-of-sight (DLOS) radio frequency (RF) signal component and a reflected RF signal component of an RF carrier signal are received from a transmitter. The reflected component is reflected from a point on the surface of the earth. The DLOS component is converted to a digital DLOS intermediate frequency (IF) signal and the reflected component that is converted to a digital reflected IF signal. Modeled reference signal parameters are generated using the digital DLOS IF signal and known locations of the one or more antennas, the transmitter, and the point. A reference signal is generated based on the modeled reference signal parameters and feedback of a previously estimated phase correction (??). The reference signal is correlated with the digital reflected IF signal to produce in-phase and quadrature-phase correlation results. Estimated carrier-to-noise ratio (C/N0) and ?? values are calculated for the digital reflected IF signal from the correlation results.