(IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 13, No. 6, 2022 Indoor Positioning System: A Review N. Syazwani C.J 1 , Nur Haliza Abdul Wahab 2 School of Computing, Faculty of Engineering Universiti Teknologi Malaysia (UTM) Johor, Malaysia Noorhazirah Sunar 3 , Sharifah H. S. Ariffin 4 School of Electrical, Faculty of Engineering Universiti Teknologi Malaysia (UTM) Johor, Malaysia Keng Yinn Wong 5 School of Mechanical, Faculty of Engineering Universiti Teknologi Malaysia (UTM) Johor, Malaysia Yichiet Aun 6 Faculty of Information and Technology, Universiti Tunku Abdul Rahman (UTAR) Perak, Malaysia Abstract—Global Positioning System (GPS) has been developed in outdoor environments in recent years. GPS offers a wide range of applications in outdoor areas, including military, weather forecasting, vehicle tracking, mapping, farming, and many more. In an outdoor environment, an exact location, velocity, and time can be determined by using GPS. Rather than emitting satellite signals, GPS receivers passively receive them. However, due to No Line-of-Sight (NLoS), low signal strength, and low accuracy, GPS is not suitable to be used indoors. As consequence, the indoor environment necessitates a different Indoor Positioning System (IPS) approach that is capable to locate the position within a structure. IPS systems provide a variety of location-based indoor tracking solutions, such as Real- Time Location Systems (RTLS), indoor navigation, inventory management, and first-responder location systems. Different technologies, algorithms, and techniques have been proposed in IPS to determine the position and accuracy of the system. This paper introduces a review article on indoor positioning technologies, algorithms, and techniques. This review paper is expected to deliver a better understanding to the reader and compared the better solutions for IPS by choosing the suitable technologies, algorithms, and techniques that need to be implemented according to their situation. Keywords—Global positioning system (GPS); indoor positioning system (IPS); real-time location system (RTLS) I. INTRODUCTION The positioning system is a method to determine the position of the object in space. In today's economy, many positioning systems are employed in all areas. In general, the positioning system can be divided into three types which are Global Positioning System (GPS), Local Positioning System (LPS), and Hybrid Positioning System (HPS) which have been highly useful in a wide variety of outdoor and indoor environments [1]. GPS is one of many satellites orbiting around the universe. GPS has several uses in a variety of fields in outdoor environments such as military, weather forecasting, vehicle tracking, mapping, farming, etc. [2]. An exact location, velocity, and time can be determined by using GPS. Rather than emitting satellite signals, GPS receivers passively receive them. The object's precision ranges from 2 to 6 meters. However, GPS is not suitable to determine the location indoors because there is No Line-of-Sight (NLoS), low signal strength, and low accuracy. LPS is one of the positioning technologies included in electronic performance and tracking systems, as it determines the position of an object in the Cartesian coordinate system [3]. It usually allows users to collect data to keep track of external load needs. Zone (up to 20 meters) and precise placement (from 0.1 to 3 meters) are types of LPS. The use of optimal LPS in an indoor environment becomes necessary with good accuracy, precision, cost, power consumption, and coverage. Wireless Fidelity (Wi-Fi), Bluetooth Low Energy (BLE), Radio Frequency Identification (RFID), and Ultrawideband (UWB) are an example of common wireless communication that is involved in LPS. However, LPS is more complex and expensive compared to GPS due to the deployment of infrastructure and hardware. Meanwhile, HBS is a combination of GPS with LPS to track items in both outdoor and indoor environments. These systems were created to address the limitations of GPS, which is extremely accurate in open spaces but fails to perform well indoors or between tall buildings. Better position estimations can be determined by hybridizing the positioning information from different technologies. This way, the combination can enhance the system's accuracy and availability in diverse locations [4]. The solution is highly optimized, with opportunistic fingerprint selection and floor change detection minimizing time-consuming processing and a battery-saving subsystem reducing power consumption by turning off unnecessary technologies. Through all of the positioning systems available, it can be divided into outdoor positioning and indoor positioning. For outdoor positioning, the GPS can always support with high accuracy, but Indoor Positioning Systems (IPS) face more challenges than outdoor positioning due to pervasive hindrances and interaction interference [5], multi-path effect, fading, reflecting, deep shadowing effect, and delay deterioration. IPS refers to the technology that helps to locate the position of people or objects inside the buildings. The location data is sent into some sort of application software to make the data useful. The design of IPS depends on what type of indoor positioning technologies, indoor positioning algorithms, and 477 | Page www.ijacsa.thesai.org