Arrestee monitoring with variable site boundaries

A method for monitoring the location of a site arrestee with reference to a permitted site, the method comprising the steps of:

• designating a first site, having a connected and closed curve of arbitrary shape as a first site boundary, as a permitted site, where a selected site arrestee is permitted to remain for a first time interval t0.ltoreq.t<t1, where t0 and t1 are selected times, with t0<t1;
• positioning a location-determining (LD) unit on the body of the site arrestee, the LD unit including an antenna and receiver/processor for receiving a timed sequence of radiowave signals from each of three or more electromagnetic signal transmitters whose transmitter locations are spaced apart from each other and from the permitted site and are known with high accuracy, where each of these electromagnetic signals has an identifying indicia and these signals contain information that allows the present location of the LD unit to be determined within the first site or outside the first site entirely by the timing relationships of the sequences of radiowave signals received by the LD unit from the signal transmitters, with no other signal sent or received by the LD unit being used in this determination of the LD unit present location;
• providing locking means for locking the LD unit to the arrestee's body so that the LD unit cannot be removed or disabled except by a special means for removal of the LD unit;
• providing the LD unit receiver/processor with an electronically sensible map of a selected portion of the Earth's surface that includes the coordinates of the permitted site or of the boundary of the first site;
• causing the LD unit receiver/processor to determine, at a selected sequence of two or more interrogation times, the present location of the LD unit and to determine whether the arrestee's present location is within the first site at such interrogation times;
• causing the LD unit to communicate an alarm signal if one or more of a specified group of conditions is present;
• designating a second site, which has a connected and closed curve of arbitrary shape as a second site boundary and is spaced apart from the first site, and a selected corridor that extends between and is connected to the first site and the second site, where the combined region consisting of the first site, the second site and the corridor has a closed continuous curve of arbitrary shape as a combined region boundary;
• redefining, for a second selected time interval t1.ltoreq.t<t2, the permitted site to include the first site, the second site and the corridor, where t2 is a selected time >t1;
• and
• redefining, for a third selected time interval t2.ltoreq.t.ltoreq.t3, the permitted site to include at least one of the first site and the second site, where t3 is a selected time >t2.