Control of the spectra of DS-SS split signals by interleaving

Direct-sequence spread-spectrum transmissions are increasingly employed in terrestrial radio-location systems to minimise interference with narrowband communications services in shared bands. Further flexibility in band planning is afforded by a scheme to generate from the high-rate sequence an integral number of lower-rate, narrow-bandwidth, 'split-signal' sequences which are transmitted in available gaps in the spectrum. The paper shows that the bandwidth and power density of the transmission may be further controlled by overlapping or interleaving the spectra of the split signals without unacceptable degradation of positioning performance due to their mutual interference.