An algorithm to determine range distance with a frequency hopping spread spectrum system

With slow frequency hopping, a propagation phase can be obtained for each frequency that is sent. The propagation phase for any single frequency yields an ambiguous range. In using the phases from a set of frequencies, it is possible to obtain a reliable, unambiguous range. This paper explains how a set of propagation delays can be used to determine a unique range distance. Multipath is taken as the only source of interference. The phase delays are calculated and plotted against the frequency. In order to find the integer part of the phase, a transition-point search method is developed; a linear regression method is applied as well. Using linear regression, a line is determined, and the intercept of this line is proportional to the range