Indoor Fingerprint Positioning Based on Wi-Fi: An Overview <s> 2. <s> In this paper, we propose a novel acoustic localization system based on fingerprinting technique. It deploys the Time Of Arrival of CDMA signals emitted by speakers to locate a microphone. The system is inspired from our earlier proposed scheme [1] which deploys the lateration method. Here, we adopt the fingerprinting technique since it is more applicable to indoor environments. The position estimation is accomplished through nonparametric kernel regression. Performance are evaluated by experiments, performed in a hall of interns in National School of Engineers of Le Mans. Results have shown that our proposed scheme provides an accuracy of 8.5 cm within 80% precision. <s> BIB001 </s> Indoor Fingerprint Positioning Based on Wi-Fi: An Overview <s> 2. <s> Although indoor localization is a key topic for mobile computing, it is still very difficult for the mobile sensing community to compare state-of-art localization algorithms due to the scarcity of databases. Thus, a multi-building and multi-floor localization database based on WLAN fingerprinting is presented in this work, being its public access granted for the research community. The here proposed database not only is the biggest database in the literature but it is also the first publicly available database. Among other comprehensively described features, full raw information taken by more than 20 users and by means of 25 devices is provided. <s> BIB002 </s> Indoor Fingerprint Positioning Based on Wi-Fi: An Overview <s> 2. <s> Indoor localization is of great importance for a range of pervasive applications, attracting many research efforts in the past decades. Most radio-based solutions require a process of site survey, in which radio signatures of an interested area are annotated with their real recorded locations. Site survey involves intensive costs on manpower and time, limiting the applicable buildings of wireless localization worldwide. In this study, we investigate novel sensors integrated in modern mobile phones and leverage user motions to construct the radio map of a floor plan, which is previously obtained only by site survey. Considering user movements in a building, originally separated RSS fingerprints are geographically connected by user moving paths of locations where they are recorded, and they consequently form a high dimension fingerprint space, in which the distances among fingerprints are preserved. The fingerprint space is then automatically mapped to the floor plan in a stress-free form, which results in fingerprints labeled with physical locations. On this basis, we design LiFS, an indoor localization system based on off-the-shelf WiFi infrastructure and mobile phones. LiFS is deployed in an office building covering over 1,600 m $^2$ , and its deployment is easy and rapid since little human intervention is needed. In LiFS, the calibration of fingerprints is crowdsourced and automatic. Experiment results show that LiFS achieves comparable location accuracy to previous approaches even without site survey. <s> BIB003
Due to the expansion of the positioning environment and the corresponding increase in fingerprint data, traditional ways of capturing fingerprint data are no longer suitable as they are time and labor intensive. Thus, it is necessary to find new ways of obtaining fingerprint data quickly and easily, like crowdsourcing BIB002 . 3. There are still many unresolved problems in Wi-Fi signal due to its disadvantages which can have a bad influence on positioning results. Thus, finding a new physical media or signal that is better than Wi-Fi may be one way to resolve the issue. According to the three points discussed above, we foresee that Wi-Fi indoor positioning will develop in the following areas: The LIFS positioning systems BIB003 proposed a new direction in indoor positioning development, which tried to reduce labor consumption in the off-line acquisition phase by using methods like crowdsourcing. This direction is also one of the new developing trends of indoor positioning. 3. In recent years, some studies have started to use information of a physical level instead of RSS to get fingerprint data like channel impulse response (CIR), which has better time stability and spatial sensitivity. Thus, using different physical media   BIB001 is also a research pathway. Indoor positioning has developed considerably in the past decade, but also faces many new challenges and potential problems like high calculating costs, and the accuracy of positioning is not stable and satisfied. The novelty of positioning systems deserves special mention, and is important in this field. The innovation of technical methods and hardware inventions inject new vitality to the indoor positioning market, which has greatly promoted indoor positioning technology development in the past decade.