Abstract: A method of designing bandwidth-efficient ranging waveforms provides waveforms usable in non-contiguous spectral bands that have low SNR thresholds and are usable at low and moderate SNR's. A set of allowed frequencies in the desired spectral region is divided into bands. A first group of band combinations is selected having a required accuracy at high SNR. Those band combinations in the first group that have the smallest autocorrelation secondary peaks are selected as a second group. Finally, waveforms are selected that occupy band combinations from the second group and have desired factors such as simultaneous or sequential transmission, a desired order of sequential transmission, and/or a desired modulation of the individual bands. Multiple simultaneous transmissions can share a set of bands, and individual transmitters can employ different modulating waveforms with good cross-correlation. In embodiments, waveforms having 4-6 bands provide a SNR threshold only 6-9 dB lower than conventional waveforms.