Augmenting GPS with Television Signals for Reliable Indoor Positioning

Abstract

This paper analyzes the theoretical performance of an idealized Assisted GPS (A‐GPS) receiver in inclement urban environments. The results suggest that if reliability, accuracy, and rapid acquisition time are important for wireless applications that are used indoors, an augmentation technology is necessary. The rest of the paper is devoted to exploring a positioning technology that uses embedded synchronization signals in TV broadcasts. The technique discussed herein could be used to position personal digital assistants (PDAs), laptops, cellular phones, two‐way radios, and asset‐tracking devices. Since the technique makes use of signals that are part of the TV standard, no changes to broadcast stations are required. The TV synchronization signals typically have a power advantage over GPS of more than 40 dB. In addition, the effects of multipath are substantially mitigated since the signals have a bandwidth of roughly 6 MHz, and superior lateral geometry for triangulation relative to stand‐alone GPS.

A Review of Indoor Localization Technologies: towards Navigational Assistance for Topographical Disorientation

“…2. Broadcast and wide area networks, including networks designed for localization purposes, such as the GPS and the Global Navigation Satellite System (GNSS) [67], and broadcast networks not originally intended for localization purposes, such as cellular phone networks [73,25] and television broadcast signals [62,63].…”

“…In particular, two such technologies were identified: television (TV) broadcast signals [62,63] and cellular phone networks [73]. Rabinowitz and Spilker [62,63] proposed the use of synchronization signals already present in the Advanced Television Signal Committee (ATSC) standard for compliant digital TV signals. As the signal properties and geometrical arrangement of the TV broadcast network have been designed to penetrate indoors, they offer significantly greater indoor coverage than GPS-based solutions.…”

“…Interference and noise are often-mentioned challenges [42,84]. Although some solutions operate within a reserved radio band [62,73,63], most of the research is conducted on open spectrum bands. This means that these solutions must account for the increased risk of interference due to other systems sharing the same frequency bands of the radio spectrum [43].…”

SCP Enabled Navigation Using Signals of Opportunity in GPS Obstructed Environments

“…Other approaches have focused on the use of cellular signals [13] and digital television signals [19] specifically to provide high accuracy indoor positioning. These techniques have produced interesting results with varying levels of accuracy.…”