New communications service for aiding deep indoor localization

The success of navigation services in the mass consumer market will depend greatly on the service availability in urban canyons and moderate indoor environments. Just extending the observation period does not help when some satellite signals are stronger than others. This paper provides a new solution that arises with the introduction of the new two-tiered spreading codes for future Galileo and modernized GPS signals. The paper illustrates a new communications service that utilizes the secondary spreading codes of the new Galileo and GPS signals to circumvent the cross-correlation problem. The communications service aligns the secondary codes such that they are orthogonal over only a partial code period.