A Review of Antennas for Indoor Positioning Systems

Abstract

This paper provides a review of antennas applied for indoor positioning or localization systems. The desired requirements of those antennas when integrated in anchor nodes (reference nodes) are discussed, according to different localization techniques and their performance. The described antennas will be subdivided into the following sections according to the nature of measurements: received signal strength (RSS), time of flight (ToF), and direction of arrival (DoA). This paper intends to provide a useful guide for antenna designers who are interested in developing suitable antennas for indoor localization systems.

A State-of-the-Art Survey of Indoor Positioning and Navigation Systems and Technologies

“…The calculation of the angle and distance is used to estimate and determine the position of a transmitter, and the information is used for tracking or for navigation purposes (Ibid.). With AOA, a position can be determined with few sensors for two-dimensional (2D) or three-dimensional (3D) positioning (Brás, Carvalho, Pinho, Kulas, & Nyka, 2012). In practice, likewise, few sensors definitely require AOA information, though several sensors are capable of using it as well when present (H. Liu et al, 2007).…”

“…TOA is sometimes called Time of Flight (TOF) (Brás et al, 2012). This is because TOA is the time taken by a signal to arrive at a receiver from a fixed transmitter, with the transmitter as the reference point (Nuaimi & Kamel, 2011).…”

“…Thus, the distance between the transmitter and the receiver can be directly calculated from the TOA, and position can be determined with the information (H. Liu et al, 2007). TOA provides high accuracy but at a cost of higher hardware complexity (Brás et al, 2012), hence TDOA attempts to eliminate the hardware complexity limitation. Figure 4 shows the TOA positioning method.…”

“…In other words, TDOA measures the difference in TOA at two different sensors and thus eliminates the need to know when the signal was transmitted (Nuaimi & Kamel, 2011;Amundson & Koutsoukos, 2009). When the position of the mobile transmitter is known, tracking can be effected with this information (Brás et al, 2012). As an improvement on TOA, TDOA eliminates the modification of the transmitter for absolute arrival time (Amundson & Koutsoukos, 2009), and hence reducing its complexity.…”

“…In other words, the RSSI approach measures the signal attenuation of transmitted signals to calculate the signal strength reduction or loss due to propagation, hence distance between mobile devices can be estimated (Ibid.). Through the estimation, position information can be acquired (Brás et al, 2012). RSSI is the relative RSS in a wireless environment; the higher the RSSI the better the signal quality (H. Liu et al, 2007).…”