Affordable Access

deepdyve-link
Publisher Website

Indoor Positioning System Based on Global Positioning System Signals with Down- and Up-Converters in 433 MHz ISM Band.

Authors
  • Uzun, Abdulkadir1, 2
  • Ghani, Firas Abdul1
  • Ahmadi Najafabadi, Amir Mohsen1
  • Yenigün, Hüsnü3
  • Tekin, İbrahim1
  • 1 Electronics Engineering, Sabanci University, Istanbul 34956, Turkey. , (Turkey)
  • 2 Radar Electronic Warfare and Intelligence Systems Division, ASELSAN A.Ş., Istanbul 34906, Turkey. , (Turkey)
  • 3 Computer Science and Engineering, Sabanci University, Istanbul 34956, Turkey. , (Turkey)
Type
Published Article
Journal
Sensors
Publisher
MDPI AG
Publication Date
Jun 25, 2021
Volume
21
Issue
13
Identifiers
DOI: 10.3390/s21134338
PMID: 34201919
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

In this paper, an indoor positioning system using Global Positioning System (GPS) signals in the 433 MHz Industrial Scientific Medical (ISM) band is proposed, and an experimental demonstration of how the proposed system operates under both line-of-sight and non-line-of-sight conditions on a building floor is presented. The proposed method is based on down-converting (DC) repeaters and an up-converting (UC) receiver. The down-conversion is deployed to avoid the restrictions on the use of Global Navigation Satellite Systems (GNSS) repeaters, to achieve higher output power, and to expose the GPS signals to lower path loss. The repeaters receive outdoor GPS signals at 1575.42 MHz (L1 band), down-convert them to the 433 MHz ISM band, then amplify and retransmit them to the indoor environment. The front end up-converter is combined with an off-the-shelf GPS receiver. When GPS signals at 433 MHz are received by the up-converting receiver, it then amplifies and up-converts these signals back to the L1 frequency. Subsequently, the off-the-shelf GPS receiver calculates the pseudo-ranges. The raw data are then sent from the receiver over a 2.4 GHz Wi-Fi link to a remote computer for data processing and indoor position estimation. Each repeater also has an attenuator to adjust its amplification level so that each repeater transmits almost equal signal levels in order to prevent jamming of the off-the-shelf GPS receiver. Experimental results demonstrate that the indoor position of a receiver can be found with sub-meter accuracy under both line-of-sight and non-line-of-sight conditions. The estimated position was found to be 54 and 98 cm away from the real position, while the 50% circular error probable (CEP) of the collected samples showed a radius of 3.3 and 4 m, respectively, for line-of-sight and non-line-of-sight cases.

Report this publication

Statistics

Seen <100 times