Analysis of Cross-Rate Interference Cancelation by Use of a Novel Phase Code Interval in Loran Navigation System

Abstract

This work concentrates on improving performance of the Loran system with rejection of cross-rate interference (CRI) by the use of a new phase code interval, the so-called Bayat Phase Code Interval (BPCI), and on the signal in the frequency domain. Indeed, interference will be canceled by removing the common spectral lines between main and interference chains in all integer coefficients of the greatest common divisor frequency of two code intervals. In addition, all interference originating from sky waves that have delay greater than 700 μs is removed by employing both the presented phase code and averaging algorithm. The results demonstrate that if the design is desirable, in the sense that the inverse of the greatest common divisor of BPCI of the considered chain with adjacent interfering chains is equal to an integer multiple of 0.5 kHz, then the proposed BPCI rejects all of the spectral lines of the undesired chain.

Precise Loran-C Signal Acquisition Based on Envelope Delay Correlation Method

“…CRI is inherent to the Loran-C system and cannot be prevented. Nevertheless, if the CRI signal is not suppressed, the acquisition result will be incorrect (especially when the CRI is intense), and the receiver will not receive the required signal [25,26]. With the increasing number of Loran-C stations being built, the amount of CRI is also increasing.…”

Suppression of Continuous Wave Interference in Loran-C Signal Based on Sparse Optimization Using Tunable Q-Factor Wavelet Transform and Discrete Cosine Transform

“…The waveform and frequency spectrum of a single pulse of a positive phase code is shown in Figure 1. As can be seen from the Figure 1, the duration of a single Loran-C pulse is 260 µs, and 99% of its energy is concentrated in the 90-110 kHz band [30,31].…”