Improving police command and control with a patrol car emitter—Call box sensor car location system

There are two basic types of car location schemes. One uses time measurement and computes location by generalized triangulation; the other identifies location by proximity to one of a multitude of receivers or transmitters which have been permanently installed. The principal problem with the latter system is installation. By taking advantage of existing grids or networks of units, in this case police telephone call boxes, much of this installation expense may be reduced. How such a system could be installed in Washington, D.C., is described in detail. Features of the system are: 1) relatively low installation cost 2) low power units creating minimum spectrum waste 3) accuracy of ±¼ mile 4) usability by a multitude of services 5) simple inexpensive equipment requirements.