Application and performance of personnel tracking systems

Many organizations would benefit from the ability to continuously locate the position of individuals as they move throughout a facility. Early tracking and direction finding was achieved using directional antennas or pseudo Doppler array techniques. It was developed for outdoor use over relatively long ranges. The reliability and accuracy fell short of current personnel tracking needs. Today, Global Positioning System (GPS) service is ubiquitous. Differential GPS provides sufficient accuracy for most personnel tracking applications. Recent cost reductions in OEM grade GPS receiver printed circuit assemblies have made GPS solutions feasible for personnel tracking. Bidirectional LEOs based satellite location systems are under development which can be applied to personnel location as well. The paper examines the practical and technical issues confronting personnel tracking systems in today´s target markets. Potential approaches to personnel tracking are presented and compared. We then introduce an alternative RF location technique utilized by the PALS (Personal Alarm Location System) from Dominion Wireless, Inc. The theory of operation of PALS is presented. Early designs and their performance are summarized. Current implementations are discussed and the capabilities and limitations are reviewed as observed in actual deployed systems. Finally, the future plans for the refinement and advancement of PALS are presented and projections of enhanced performance supplied