You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Indoor location systems in emergency scenarios: A Survey 
Chapter Title:  INTRODUCTION 
1. Abstract of Cited Paper (BIB001):  This paper presents an indoor navigation system based on sensor data from first responder wearable modules. The system combines an inertial measurement unit, a digital camera and a radio frequency identification device in a way that allows the advantages of each sensor to be fully exploited. The key to this synergy is the extracted qualitative criteria which characterize the performance of each sensor subsystem at various first responder activities and operational conditions under certain time intervals. The accuracy of the detected walking pattern through measurements of the acceleration magnitude from the inertial sensor is utilized for the performance evaluation of the dead-reckoning algorithm. The amount of correct feature matches is linked to the three-dimensional scene representation from the camera navigation subsystem and finally, the degree of probability of each radio frequency identification location estimate is exploited as a straightforward qualitative criterion. The final fused location estimation is extracted after applying fuzzy if–then rules at each time interval. Since the inertial sensor suffers from accumulated drift, the rules of the fuzzy inference system drop the measurements from the inertial measurement unit whenever the other two subsystems perform adequately. Extensive comparison and experimental results based on the proposed architecture have shown not only better navigation effectiveness and lower positioning error compared with other first responder navigation systems but also increased accuracy in various and challenging operational conditions. 
2. Abstract of Cited Paper (BIB002):  Recent advances in CCD technologies, processing speed and image understanding have been driving the development of the camera-based positioning systems. An improved performance of optical systems has triggered image based positioning methods to become an attractive alternative for applications in industrial metrology as well as for robot- and pedestrian navigation. This paper provides a survey of current optical indoor positioning approaches. Different systems are briefly described and categorized based on how the images are referenced to the environment. 
3. Abstract of Cited Paper (BIB003):  The availability of a reliable and precise tracking system for relief units operating in mission critical scenarios would drastically improve the situational awareness and thus facilitate the mission planning and accomplishment as well as increase the safety of human resources. Thus, the demand for such a system is very high both in the military and in the emergency and crisis intervention domain. While there are solutions like GPS for the localization in open areas, problems arise in urban scenarios and indoors due to insufficient or failed signal reception. For indoor use, multiple alternative localization concepts exist that are suited for different use cases and expose varying properties in precision, complexity and required preconditions. The deployment within mission critical scenarios implicates explicit restrictions and requirements so that only some of the techniques are adept or have the potential of being used here. This article identifies the commonly issued requirements to an indoor tracking in mission critical scenarios and introduces basic techniques for position estimation. Subsequently, existing indoor tracking systems specifically in the field of mission critical scenarios are reviewed with a focus on their capabilities in terms of reliability and accuracy. By doing so, an overview of current approaches in this field is given. Furthermore, the most adept techniques are classified with respect to the requirements within mission critical scenarios. 
4. Abstract of Cited Paper (BIB004):  With the continual miniaturisation of sensors and processing nodes, Pedestrian Dead Reckoning (PDR) systems are becoming feasible options for indoor tracking. These use inertial and other sensors, often combined with domain-specific knowledge about walking, to track user movements. There is currently a wealth of relevant literature spread across different research communities. In this survey, a taxonomy of modern PDRs is developed and used to contextualise the contributions from different areas. Techniques for step detection, characterisation, inertial navigation and step-and-heading-based dead-reckoning are reviewed and compared. Techniques that incorporate building maps through particle filters are analysed, along with hybrid systems that use absolute position fixes to correct dead-reckoning output. In addition, consideration is given to the possibility of using smartphones as PDR sensing devices. The survey concludes that PDR techniques alone can offer good short- to medium- term tracking under certain circumstances, but that regular absolute position fixes from partner systems will be needed to ensure long-term operation and to cope with unexpected behaviours. It concludes by identifying a detailed list of challenges for PDR researchers. 
5. Abstract of Cited Paper (BIB005):  In order to provide location information for indoor applications and context-aware computing, a lot of research is being done since last decade for development of real-time Indoor location system. In this paper, we have investigated indoor location concepts and have focused two major technologies used in many indoor location systems i.e. RF and ultrasonic. An overview of various RF systems that use different RF properties for location estimation has been given. Ultrasonic systems have been reviewed in detail as they provide low cost fine grained location systems. A few well known ultrasonic location systems have been investigated with a comparison of the system based on performance, accuracy and limitations. 
6. Abstract of Cited Paper (BIB006):  This paper introduces the significance of indoor positioning and analyzes the related problems. The latest research on indoor positioning is introduced. Further, the positioning accuracy and the cost of typical local and wide area indoor positioning systems are compared. The results of the comparison show that Time & Code Division-Orthogonal Frequency Division Multiplexing (TC-OFDM) is a system that can achieve real-time meter-accuracy of indoor positioning in a wide area. Finally, in this paper, we indicate that the seamless high-accuracy indoor positioning in a wide area is the development trend of indoor positioning. The seamless Location Based Services (LBS) architecture based on a heterogeneous network, key technologies in indoor positioning for decimeter-accuracy and seamless outdoor and indoor Geographic Information System (GIS) are elaborated as the most important research fields of future indoor positioning.

Literature Review:
In emergency scenarios the fast conduction of victims to exit (evacuation) and the precise monitoring of the rescuers 1 position are both important to reducing deaths and injuries. BIB002 We consider "rescuer" as any operational forces member, comprising medical, police and fire brigade. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. SBSI 2015, May 26th-29th, 2015, Goiânia, Goiás, Brazil Copyright SBC 2015. To monitor rescuers command centers use radio communication, where the team member directly reports his/her position. In situations of stress, disorientation or unconsciousness the active reporting strategy may fail  . Location positioning systems can be used to automatically gather the positioning of rescuers and victims. The most usual location technique, the GPS, does not work well indoor because of interferences generated by physical barriers (such as walls and furniture) and sources of radio signal  . Thus, many techniques have been developed to provide the location of mobile devices in indoor environments with greater accuracy. However, emergency situations have particular characteristics (e.g., smoke, blackout) that can reduce visibility and make useless the current indoor positioning systems (IPS). Most of existing surveys approaching location systems focus on the adopted technique, without considering the specifics of emergency scenarios  BIB003 BIB005 BIB006 BIB001 BIB007 . Only one review of indoor positioning systems for emergency situations was identified BIB004 . However, it is from 2011 and does not connect the characteristics of emergencies scenarios with most modern techniques. Besides, there is a lack to categorize the requirements of emergency situations for indoor location systems. For example, luminosity is essential for indoor location techniques based on images. However, on emergency situation we can experiment scenarios as lack of power or presence of smoke that compromise the luminosity. This work aims to present the state-of-the-art of solutions for indoor location in emergency scenarios. Our research questions are: "What are the requirements for using indoor location systems in emergency situations? "; "Existent indoor location systems support those requirements? "; "There are unattended demands for a new indoor location solution for this domain? ". The paper is organized as follows. Section 2 discusses related work. Section 3 presents the survey protocol. Section 4 reviews and presents a taxonomy of main indoor location techniques. Section 5 discusses the survey results, which include: a requirements list of indoor location systems for emergency scenarios, a summary and analysis of the main works in indoor location for emergency scenarios. Section 6 presents our conclusions and future works.