Patent ID: 7668532

Claim:
A detection system for selectively determining the presence of individuals proximate a structure, said detection system comprising: a base unit at said structure; a first remote unit operated by one of the individuals and a master remote unit operated by another individual, said remote units being cellular telephones, said remote units and said base unit having geographical dependent bidirectional communications modules with limited transmission range of about 100 m or less, said module of said first remote unit transmitting a first identification signal; receiving means associated with said base unit for receiving said first identification signal when said first remote unit is within said limited transmission range of the structure; selection means operatively associated with said base unit for selectively establishing an authorized user status to said first remote unit upon receipt of said first identification signal; instant wireless connectivity means for transmitting over a cellular network from said base unit to said master remote unit the presence of said first remote unit within said limited transmission range of said structure.