<p>The number of connected mobile
devices and Internet of Things (IoT) is growing around us, rapidly. Since, most
of the people daily activities are relying on these connected things or
devices. Specifically, this past year (with COVID-19) changed daily life in
abroad and this is increased the use of IoT enabled technologies in health
sector, work, and play. Further, the most common service via using these
technologies is the localization/positioning service for different applications
including: geo-tagging, billing, contact tracing, health-care system,
point-of-interest recommendations, social networking, security, and more. Despite the availability of a large number of
localization solutions in the literature, the precision of localization cannot
meet the needs of consumers. For that reason, this paper provides an in-depth
investigation of the existing technologies and techniques in the localization
field, within the IoT era. Furthermore, the benefits and drawbacks of each
technique with enabled technologies are illustrated and a comparison between the
utilized technologies in the localization is made. The paper as a guideline is
also going through all of the metrics that may be used to assess the
localization solutions. Finally, the state-of-the-art solutions are examined,
with challenges and perspectives regarding indoors/outdoors environments are
demonstrated.</p>