Indoor Localization is of great importancce in a range of pervasive applications, but existed methods do not perfectly solve this problem, most radio-based solutions, for example, require a process of site survey, which costs much on manpower and time. Therefore, the papers put forward novel solutions based on smart phone sensors, one indoor localization system called LiFS constructs the radio map of floor plan by mapping the fingerprint space to stress-free plan, the other identifies certain locations in indoor environment and uses mobile services to "sense" the landmarks, afterwards, tracks user locations between them, thus achieving indoor localization.
The 2 papers referred above are listed below if you may be interested to take a look at them:
1) Locating in Fingerprint Space: Wireless Indoor Localization with Little Human Intervention
——Yunhao Liu etc. Tsinghua University, Mobicom 12
2) No need to War-Drive: Unsupervised Indoor Localization reported in 36Kr(link)
——He Wang etc, Duke University, Mobisys 12