Detection performance of security system using radio waves based on space-time signal processing

Shun Kawakami, Kazuki Okane, Tomoaki Ohtsuki

Research output: Contribution to journalConference articlepeer-review

11 Citations (Scopus)


We proposed the indoor event detection system with signal subspace spanned by eigenvector for office or home security. The system monitors a whole room or home with only a pair of transmitter and receiver. The receiver uses an antenna array. We monitor events based on not received signal strength that is susceptible to noise but signal subspace spanned by eigenvector that is inherent to its environment. When an event (e.g. a person intrudes into a house) occurs, the propagation environment changes, and thus the signal subspace changes. Monitoring this change, we detect an event. The change of eigenvector tells us whether a person is in motion or remains motionless. We reported the principle of our security system and some fundamental detection performance of the system using dipole antennas arranged linearly or circularly as the receiver, although they are not necessarily arranged regularly. In this paper, we report various experimental detection results of the proposed security system using patch antennas set up on a box at the receiver such as intrusion, baggage stolen and the effect of outside of the room. Moreover, we evaluate the detection performance of the eigenvalue-based security system. We show that the eigenvalue-based security system can detect some events that the eigenvector-based security system cannot. Then we show that depending on application demands, using both the eigenvector and the eigenvalue for the security system is a promising technique.

Original languageEnglish
Pages (from-to)171-178
Number of pages8
JournalProcedia - Social and Behavioral Sciences
Issue number1
Publication statusPublished - 2010
Event1st International Conference on Security Camera Network, Privacy Protection and Community Safety 2009, SPC2009 - Kiryu, Japan
Duration: 2009 Oct 282009 Oct 30


  • Array antenna
  • Event detection
  • Patch antenna
  • Security

ASJC Scopus subject areas

  • Social Sciences(all)
  • Psychology(all)


Dive into the research topics of 'Detection performance of security system using radio waves based on space-time signal processing'. Together they form a unique fingerprint.

Cite this