Hybrid Visible Light and Ultrasound-Based Sensor for Distance Estimation

Abstract

Abstract:Distance estimation plays an important role in location-based services, which has become very popular in recent years. In this paper, a new short range cricket sensor-based approach is proposed for indoor location applications. This solution uses Time Difference of Arrival (TDoA) between an optical and an ultrasound signal which are transmitted simultaneously, to estimate the distance from the base station to the mobile receiver. The measurement of the TDoA at the mobile receiver endpoint is proportional to the distance. The use of optical and ultrasound signals instead of the conventional radio wave signal makes the proposed approach suitable for environments with high levels of electromagnetic interference or where the propagation of radio frequencies is entirely restricted. Furthermore, unlike classical cricket systems, a double-way measurement procedure is introduced, allowing both the base station and mobile node to perform distance estimation simultaneously.

Optical Boundaries for LED-Based Indoor Positioning System

“…Proximity [9] 1-2 m Low Mobile phone [16] m Medium Exp-Setup, dsPIC Board [12] 4.5 m Medium MSP 430 [17] 0.01-0.48 m Low [18] 0.3-0.6 m Medium [19] 0.4 m Medium Exp-Setup, RF, LED Fingerprinting [20] 5 cm Low Exp-Setup + E4832A [21] 10 cm Medium [22] 10 cm Low [10] 15-20 cm Medium Exp-Setup, Covered [23] 10 cm Medium [24] 85 cm Medium [25] 1-2 cm Medium [26] 20-80 cm Low [27] 1.69 cm Medium [28] 7 cm Low [29] 5 cm Medium Camera, Robot [30] 5 cm High Exp-Setup [31] 1.3 cm High Exp-Setup, mobile robot [32] 10 cm Medium [33] 10 cm Medium TDoA [34] 2-5 cm High [35] 1 cm High [36] 3.9 cm Medium [37] 0.3 cm Medium [38] 2 cm High [6] -cm AoA [11] 1-2 m Medium Exp-Setup, 5331 APD [39] 0.3 m Medium Mobile phone [40] 5-30 cm High [41] 10 cm High Tripod, protractor, PC [42] 8 cm High [43] 5 cm Medium Table 1. Cont.…”

“…The experimental setup is used to measure the values of v n , v f , σ n , and σ f using an (Agilent) oscilloscope. The measured parameters are used to compute the value of Q by (6). Without loss of generality, we assume unity of receiver responsivity coefficient, and using the values from the experimental measurements as presented in Table 4, the total receiver noise is computed as σ 2 t = 1.04 × 10 −12 V 2 .…”

“…However, the possibility of multipath reflections and interference with other RF-based devices makes RF unsuitable for indoor positioning [5]. The use of magnetic or induction-based systems and ultrasound systems has been investigated for indoor positioning, but these systems come with high installation costs [6,7]. In addition, magnetic systems can interfere with other sensitive electromagnetic signals (such as those in hospitals).…”

A Novel Ranging Technique Based on Optical Camera Communications and Time Difference of Arrival

“…As mentioned above, the proposed system is a variation of the scheme presented in [10]. Fundamentally, that system uses an optical signal instead of the RF one included in Cricket devices [49], and introduces an additional optical receiver and emitter to provide distance-measurement capability on both devices.…”

“…Several schemes for distance estimation have been proposed such as Received Signal Strength (RSS), Time of Flight (ToF), Angle of Arrival (AoA) or Time Difference of Arrival (TDoA) [6]. In this work, a TDoA scheme based on a Visible Light Communication (VLC) measurement system, as previously proposed in [10], is presented. The main contribution of this work is the use of OCC techniques and image processing for measuring the signal's time of flight between the base station (BS) and the mobile station (MS).…”