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 Human Navigation Systems: A Survey 
Chapter Title:  User Input 
1. Abstract of Cited Paper (BIB001):  This paper proposes a walking navigation system for the blind. The system is based on a comparison of data obtained by a pedometer and a terrestrial magnetic sensor and prearranged teaching data of a route to a destination. The system gives an appropriate instruction (using voice and buzzer sound) during a user's walk. This paper mainly describes experiments designed to clarify the characteristics of the system. The results show that the nodes of a walking route for teaching should be less than 50 m, since the maximum error of the system is about 10% in a walking distance of 50 m. The experiments also show that the walkers (sighted men with eye masks) were guided by the system along a course of about 900 m, taking about 40 to 50 mins. © 1998 Scripta Technica. Syst Comp Jpn, 28(13): 36–45, 1997 
2. Abstract of Cited Paper (BIB002):  The research we are reporting here is part of our effort to develop a navigation system for the blind. Our long-term goal is to create a portable, self-contained system that will allow visually impaired individuals to travel through familiar and unfamiliar environments without the assistance of guides. The system, as it exists now, consists of the following functional components: (1) a module for determining the traveler's position and orientation in space, (2) a Geographic Information System comprising a detailed database of our test site and software for route planning and for obtaining information from the database, and (3) the user interface. The experiment reported here is concerned with one function of the navigation system: guiding the traveler along a predefined route. We evaluate guidance performance as a function of four different display modes: one involving spatialized sound from a virtual acoustic display, and three involving verbal commands issued by a synthetic speech display. The virtual display mode fared best in terms of both guidance performance and user preferences. 
3. Abstract of Cited Paper (BIB003):  A location-aware navigation system has been developed and implemented for the visually disabled or visually impaired; the system is designed to improve individuals' independent mobility. This self-contained, portable system integrates several technologies, including mobile personal digital assistants, voice synthesis, a geographic information system (GIS), and a differential Global Positioning System (DGPS). The system is meant to augment the various sensory inputs available to the visually impaired user. It provides the user with navigation assistance, making use of voice cues iterating contextual building and feature information at regular intervals, through automatic GPS readings and a GIS database. To improve the efficiency of the retrieval of contextual information, an indexing method based on road segmentation was developed to replace the exhaustive search method. Experimental results show that the performance of the system on searching the buildings, landmarks, and other features around a road has been significantly improved by using this indexing method. 
4. Abstract of Cited Paper (BIB004):  We present a robot-assisted wayfinding system for the visually impaired in structured indoor environments. The system consists of a mobile robotic guide and small passive RFID sensors embedded in the environment. The system is intended for use in indoor environments, such as office buildings, supermarkets and airports. We describe how the system was deployed in two indoor environments and evaluated by visually impaired participants in a series of pilot experiments. We analyze the system's successes and failures and outline our plans for future research and development. 
5. Abstract of Cited Paper (BIB005):  Almost 2 million Japanese citizens use Navitime, a mobile phone-based navigation service that incorporates various modes of transportation. User experiences reveal implications for designing urban-computing services. Location-based services are a key pervasive computing application that could deeply influence urban spaces and their inhabitants. Recent advances in mobile phones, GPS, and wireless networking infrastructures are making it possible to implement and operate large-scale location- based services in the real world. 
6. Abstract of Cited Paper (BIB006):  We describe a body-worn sensor suite, environment representation, set of algorithms, and graphical-aural interface designed to provide human-centered guidance to a person moving through a complex space. The central idea underlying our approach is to model the environment as a graph of visually distinctive places (graph nodes) connected by path segments (graph edges). During exploration, our algorithm processes multiple video-rate inputs to identify visual features and construct the “place graph” representation of the traversed space. The system then provides visual and/or spoken guidance in user-centered terms to lead the user along existing or newly-synthesized paths. Our approach is novel in several respects: it requires no precise calibration of the cameras or multi-camera rig used; it generalizes to any number of cameras with any placement on the body; it learns the correlation between user motion and evolution of image features; it constructs the place graph automatically; and it provides only coarse (rather than precise metrical) guidance to the user. We present an experimental study of our methods applied to walking routes through both indoor and outdoor environments, and show that the system provides accurate localization and effective navigation guidance.

Literature Review:
Many navigation systems are facilitated using mobile devices where input provision is limited due to small screens and buttons. Some systems use conventional input techniques, such as touch screens BIB001 , keypads BIB003 , and push-button switches BIB007 BIB002 . This requires users to hold the device in their hand all the time and look for the button or right place on the screen to press. For emergency crew or individuals with visual impairments interaction as such is not useable. Speech recognition has been widely used BIB006 BIB004 BIB005  to receive user's input, for example for retrieving a target destination to navigate to. This approach requires less user attention and it is more natural. However, ambient sounds in the environment can interfere with the voice recognition system or might interfere with a user having a conversation with someone else. Table 5 provides an overview of the different techniques used for providing input.