The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
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Indoor Location System based on TDOA between RF and Ultrasonic Signal

RF와 초음파 사이의 TDOA에 기반한 실내 측위시스템

  • 서영동 ((주)피앤이솔루션 기술연구소) ;
  • 송문규 (원광대학교 전자및제어공학부)
  • Published : 2009.06.30
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Abstract

Recently, an indoor location-aware technology has been focused on as a key technology for context awareness in ubiquitous computing environments. The conventional Cricket system was designed with a non-centralized architecture, which has advantages in terms of user privacy, deployment, scalability, decentralized administration, network heterogeneity, and low cost. In this paper, an indoor location system based on TDOA between RF and ultrasound signals is designed, which improves the Cricket system. A 2.4GHz frequency is employed for transmitting RF messages, which is in an ISM band. The beaconing frequency is doubled to enhance the channel utilization rate. The ultrasonic pulse duration is optimized to increase the coverage of ultrasonic signals. The function of calculating location coordinates is embedded in a listener. The location-update rate and location accuracy are also improved.

최근 유비쿼터스 컴퓨팅 환경에서 상황인식 서비스를 위한 핵심 기술로 실내 위치인식 기술이 주목받고 있다. 기존에 연구된 크리켓은 비중앙집중형 구조로 설계되어 사용자의 프라이버시를 보호하고, 확장, 유지관리가 용이하며, 하드웨어 비용이 저렴한 잇점이 있다. 이 논문에서는 RF와 초음파신호 사이의 TDOA에 기반한 크리켓 시스템보다 개선된 실내 측위시스템을 설계하였다. RF 메시지를 전송하기 위하여 ISM 대역인 2.4GHz 주파수를 사용하였다. 비콘에서 RF와 초음파를 전송하는 빈도(Beaconing frequency)는 채널 이용률을 높이기 위해 2배 높였다. 초음파 펄스 지속시간은 초음파 신호의 거리를 증가시키면서 최적화 시켰다. 또한 위치좌표를 계산하는 기능을 리스너에 내장시켰다. 실험결과 위치 업데이트율과 위치 정확도는 향상되었다.

Keywords

References

  1. G. Chen and D. Kotz, 'A Survey of Context-Aware Mobile Computing Research,' Dartmouth Computer Sciecne Tech. ReportTR2000-381, 2000. (ftp.cs.dartmouth.edu/TR/TR2000-381.ps.Z)
  2. B. Schilit, N. Adams, and R. Want, 'Context-aware computing applications,' In Proc. of IEEE Workshop on Mobile Computing Systems and Applications, 85-90, December,1994
  3. M. Satyanarayanan, 'Pervasive computing:vision and challenges,' IEEE Personal Communications, pp.10-17, Aug., 2001 https://doi.org/10.1109/98.943998
  4. Dey, A.K., 'Understanding and Using Context,' Personal and Ubiquitous Computing Journal, Vol. 5(1), 2001, pp. 4-7 https://doi.org/10.1007/s007790170019
  5. Jeffrey Hightower, and Gaetano Borriello, 'A Survey and Taxonomy of Location Systems for Ubiquitous Computing,' Technical Report UW-CSE 01-08-03, University of Washington,Aug. 2001. (http://portolano.cs. washington.edu/projects/location/)
  6. Jeffrey Hightower and Gaetano Borriello,'Location Systems for Ubiquitous Computing,' IEEE Computer Society Press, vol. 34, no. 8, pp. 57-66, Aug. 2001 https://doi.org/10.1109/2.940014
  7. R. Want, A. Hopper, V. Falcao, J. Gibbons, 'Theactive badge location system,' ACM Trans. onInformation Systems, 10(1), pp.91-102, Jan.1992 https://doi.org/10.1145/128756.128759
  8. A. Harter, et. al., 'The anatomy of acontext-aware applications,' Proc.of 5th Annua lACM/IEEE International Conf. On MobileComputing and Networking (Mobicom1999), pp.59-68, Aug. 1999
  9. Nissanka Bodhi Priyantha, 'The Cricket Indoor Location System,' PhD Thesis, Massachusetts Institute of Technology, June 2005
  10. P. Bahl and V. Padmanabhan, 'RADAR: anin-building RF-based user location and trackingsystem,' Proc. of IEEE INFOCOM, pp.775-784,March 2000
  11. Ubisense homepage. (http://www.ubisense.net.)
  12. Ultra Wideband working group homepage. (http://www.uwb.org.)
  13. Microsoft Research, Easy living, Website, 2001. (http://222.research. microsoft.com/easyliving)
  14. Datasheet, TC77 Thermal Sensor with SPIInterface, Microchips, 2002. 8.