Indoor localization based on multiple LEDs position estimation

Abstract

This paper describes the simulation results and hardware implementation of an inexpensive, low-complexity LED based indoor positioning system. Localization by multiple LEDs estimation model (MLEM) approximates position of a mobile receiver by the acquisition of positional information from LED transmitters. Multiple LED orientation can either be with or without overlap. Receivers in a no-overlap LED orientation experience only single access while multiple access receivers are designed for orientations with overlaps. Single and multiple access systems were developed and implemented by the use of low cost ATMEG 328 microcontroller. Since multiple LEDs transmit data at the same wavelength and are asynchronous, overlap in multiple access system causes interference. The possibility of this interference is reduced by packet based pulse duration multiplexing (PDM) and a low duty cycle transmission protocol. By the use of MLEM, root mean square error in position estimation is reduced to about 1 percent of the length an indoor location. Experimental results show that overlap increases positional accuracy over a wider coverage region and that the multiple access system allows for a more reliable positioning.

Optimal beam radius for LED-based indoor positioning algorithm

“…Though VLC can lead to highly accurate position estimation, the existing positioning algorithms have not been able to tap into the potential of this technology in a practical and low complexity manner. These algorithms have proven to be reasonably successful at reducing the error in position estimation and also are relatively inexpensive [15], but they still suffer from the problem of packet loss due to interference created by overlapping light beam regions. In this research this problem of overlapping light beams is used to the system's advantage and a simple and practical positioning algorithm is proposed which helps reduce the anomaly in position estimation to enhance the system accuracy.…”

Optical Boundaries for LED-Based Indoor Positioning System

“…The accuracy of positioning is dependent on the size of the footprint of the LED. Proximity-based indoor positioning systems have been shown to improve accuracy with the use of overlapping LED beams in a MLEM while keeping the receiver wearable [19,75]. By uniquely programming each LED, more identifiable regions are created as illustrated in Figure 1a,b.…”

“…However, this model has the possibility of LED data packet collisions in the overlap regions. By using packet duration multiplexing (PDM), the collision can be reduced [75,78]. However, Ref.…”

“…In this section, the effect of a defined optical boundary on the positioning accuracy for a given MLEM-based system is presented in terms of positioning error. To show the effect of the optical boundary on positioning error, a Monte Carlo simulation is used to calculate the positioning error of the overlap-based proximity technique introduced in Reference [75] and the process is presented in Algorithm 1.…”

Optical Wireless Communication Based Indoor Positioning Algorithms: Performance Optimisation and Mathematical Modelling

“…This situation happens when the light beam regions of LEDs of the OWC system, which are transmitting their location information in the form of modulated optical signal, overlap. In recent research [43], the multiple LED estimation model (MLEM) is proposed to establish an explicit coordination between LEDs and separate signals at the receiver. In MLEM, the positional information is encoded using pulse duration multiplexing (PDM) and the data is modulated using on-off keying (OOK) to a higher frequency.…”