The absence of the Global Positioning System (GPS) inside buildings makes indoor navigation more difficult compared to outdoor environments. This paper provides a summary of visually impaired indoor navigation technologies to identify the needs of the visually impaired to safely navigate indoors. Radar as a sensor is preferred because it works in conditions where other systems cannot work properly and has unique features. In particular, this paper reviews different radar SLAM and ego-motion estimation approaches that can aid indoor navigation. This paper concludes with a brief insight into the future direction for a novel radar-based wearable indoor navigation system.