A method and system for multi-tracking among independent individuals without a monitoring center, where an individual is a person, a vehicle, or any other property, enables the individuals to be networked in a group and each individual to search and track other individuals of interest. The portable multi-tracking...http://www.google.com.hk/patents/US7143130?utm_source=gb-gplus-share專利 US7143130 - Portable multi-tracking method and system
