International Journal of Computer Applications (0975 – 8887) Volume 140 – No.7, April 2016 1 Survey of Indoor Positioning Measurements, Methods and Techniques Siddhesh Doiphode Department of Computer Engineering Shree L.R. Tiwari COE Mumbai University J.W. Bakal, PhD Principal, Shivajirao S. Jondhale College of Engineering Mumbai, India Madhuri Gedam Department of Computer Engineering Shree L.R.Tiwari COE Mumbai University ABSTRACT The continuous improvement in the development in the field of communication networks and mobile computing, location based service (LBS) has become very popular in recent years. For outdoor positioning service the Global Positioning Systems (GPS) are the earliest widely used modern systems. In GPS technology Satellite signals cannot penetrate in indoor environment since they are blocked by building obstructions thus satellite signal cannot provide good accuracy in indoor environments due to lack of LoS(Line Of Sight). On doing research it is being observed that in the near future, indoor positioning will gain more demand as people spend more than 70% of their lives in indoor environment. A large variety of technologies have been designed for dealing with the problem since the indoor environments are very difficult to track .The paper also provide brief description on various indoor wireless tracking measurements, methodologies and technologies. The paper illustrates the theoretical points, the main tools, and the most promising technologies for indoor tracking infrastructure. General Terms Location Based Services, Indoor Positioning System, Fingerprinting Method, Propagation model. Keywords Trilateration, Triangulation, Propagation Model. 1. INTRODUCTION Due to widespread advances of devices and technologies Indoor real-time locating systems (RTLSs) have been gaining relevance. RTLSs is indoor tracking where objects, vehicles, or people are tracked within a building or enclosed infrastructure. In market various indoor positioning solutions have been proposed such as Cellular-network [1], Computer Vision [2], Ultrasound [3], Infrared Ray [4], Bluetooth technique [5] etc. The early RTLSs hat uses ultrasound to the most recent ultra-wideband (UWB) techniques which are some of the adhoc solutions for indoor tracking. All these systems are able to provide accurate results however, they rely on additional hardware or large-scale infrastructures which incurs more cost. Due to significant cost, energy consumption and specific environment range limitations, such system are hard to deploy. The latest trend in addressing indoor tracking problem is to use standard, low cost and make use of existing available technologies to reduce the cost. The forefront player in this competition is the smart phone enabled indoor positioning system (IPS) [6]. IPS based on Wi-Fi fingerprint is one of the most exploited technique and have received considerable attention recently[7] .The technologies used in the system are heterogeneous which encompasses Wi-Fi, UWB, radio-frequency identification (RFID), Bluetooth, near- field communication (NFC), Long-Term Evolution (LTE).The latest challenges in indoor tracking is not only to design specialized sensor but also to implement data fusion method that can exploit the available technologies. The WLAN RSS measurement techniques are used in Propagation model and Fingerprinting which are one of the fundamental method .To estimate the location of a mobile user with the help of the received signal strength information the path loss of the signal is taken into account. Geometric Techniques like trilateration [8] and triangulation [9,10] can be used to determine the coordinates of a user. When the accuracy requirement is not very high the propagation model approach is relatively simple and efficient . However, due to the noise of wireless signals and the interference of indoor obstructions such as multi-story floors, doors and walls accurately measuring the distance based on signal attenuation is still difficult [11]. In this survey we are dealing with the problem of indoor wireless tracking. We present the type of measurement, different models and technologies used in Indoor tracking system. The remainder of this paper is organized as follows. Section 2 introduces the type of measurement and Section 3 describes the overview of the different methods. Section 4 presents different technologies of IPS followed by conclusion. 2. TYPES OF MEASUREMENT This section present different type of measurements used for tracking purpose. 2.1 RSS The RSS measurement mainly based on the principle that greater the distance between two nodes, the weaker the strength of the received signal. Wi-Fi based IPS is commonly based on this type of measurement. The mapping between measured RSS and the distance between the receiving and the transmitting node is measured with the mathematical model using EuDistance. The Euclidean distance which can be calculated as shown in the below equation is used to measure the distance between an online RSS value and the offline training database RSS records[12]. The smallest distance is used to decide which offline fingerprint is selected to determine the location of the user. EuDistance = √ − ′   1 2