Location-Based Services (LBS) are mobile applications that provide information depending on the location of the user. To make LBS work, different system components are needed, i.e., mobile devices, positioning, communication networks, and service and content provider. Almost every LBS application needs several key elements to handle the main tasks of positioning, data modeling, and information communication. With the rapid advances in mobile information technologies, LBS have become ubiquitous in our daily lives with many application fields, such as navigation and routing, social networking, entertainment, and healthcare. Several challenges also exist in the domain of LBS, among which privacy is a primary one. This topic introduces the key components and technologies, modeling, communication, applications, and the challenges of LBS.
A global navigation satellite system (GNSS), composed of user receivers, satellites, and ground control stations, is designed to provide accurate positions in 3-dimensional space. The Global Positioning System (GPS) is one of four GNSS freely available today. The fundamental GNSS approach is widely used today in cellphones, automobiles, autonomous vehicles, uncrewed aerial vehicles, and even as tagged luggage or bicycles. Significant improvements in the GNSS approach is available to the educated mapping scientist with an appropriate GNSS receiver/antenna, the appropriate environmental context, and processing of the satellite signals. This chapter provides the reader the fundamental concepts involved in the GNSS approach. With such knowledge the reader can make informed decisions about receivers, their use in the environment, and processing approaches for their unique applications.