Digital system for estimating signal non-energy parameters using a digital Phase Locked Loop

摘要

A digital system of measuring parameters of the signal (phase, frequency and frequency derivative) received in additive mixture with Gaussian noise. The system is based on the use of variables of a PLL for calculating preliminary estimates of parameters and calculating the corrections for these estimates when there is a spurt frequency caused by a receiver motion with a jerk. A jerk is determined if the low pass filtered signal of the discriminator exceeds a certain threshold. The jerk-correction decreases the dynamic errors. Another embodiment includes a tracking filter for obtaining preliminary estimates of parameters to reduce the fluctuation errors. Estimates are taken from the tracking filter when there is no jerk and from the block of jerk-corrections when there is a jerk.

主权项

1. A system for estimating parameters of an input signal, the system comprising:
a) a digital phase locked loop that includes:
i) a phase discriminator that determines a phase difference zid between the input signal and reference signals from a Numerically Controlled Oscillator (NCO); andii) a loop filter with a control period Tc that generates a phase control signal φir for the NCO and a frequency control signal fir for the NCO; and b) a block for calculation of full phase φiNCO according to
φiNCO=φi-1NCO+φir·ΔφNCO+fi-1·ΔωNCO·Tc, where ΔφNCO is a phase step size in the NCO, and ΔωNCO is a frequency step size in the NCO; c) a low-pass filter inputting the phase difference zid and outputting ziA; d) a block that uses φiNCO for generation of:
a preliminary estimate {circumflex over (φ)}ic,E for a phase of the input signal, anda preliminary estimate {circumflex over (ω)}ic,E for a frequency of the input signal; e) a threshold unit outputting a true/false value Ji based on ziA; and f) a block for jerk-corrections of the preliminary estimates that generates an estimate {circumflex over (φ)}ic for a phase of the input signal, and an estimate {circumflex over (ω)}ic for the frequency of the input signal, based on Ji, ziA, {circumflex over (φ)}ic,E and {circumflex over (ω)}ic,E.