Patent ID: 11889390
Assignee: ROOMZ S.A.
Field: Digital communication (Electrical engineering)
Classification: CPC G  H  Y | IPC H

Claim 8:
9. A method for monitoring a state of occupancy of a pre-determined area, the method comprising:
receiving a first report of a time when a movement was detected within a first pre-determined zone within the pre-determined area from a first sensor, the first sensor being a battery-operated passive infra-red motion sensor, the first report including a time when the movement was detected according to a local real-time clock of the first sensor and a message delivery time for the first report according to the local real-time clock of the first sensor;
receiving a second report of a time when a movement was detected within a second pre-determined zone within the pre-determined area from a second sensor, the second sensor being a second battery-operated passive infra-red motion sensor, the second report including a time when the movement was detected according to a local real-time clock of the second sensor and a message delivery time for the second report according to the local real-time clock of the second sensor;
comparing the message delivery time for the first report with a reference clock and using the comparison to calculate the time that the movement was detected by the first sensor in terms of the reference clock;
comparing the message delivery time for the second report with the reference clock and using the comparison to calculate the time that the movement was detected by the second sensor in terms of the reference clock;
verifying, in a database having topographic data on the first and second pre-determined zones, whether the first and second sensors have overlapping footprints; and
attributing the two movements to be a single movement by a same live presence if the two movements have the same time in terms of the reference clock and if the two footprints have an overlap;
attributing the two movements to be two separate movements by two separate live presences if the two movements have the same time in terms of the reference clock and if the two footprints do not overlap; and
attributing the two movements to be separate movements by different live presences if the two movements have different times in terms of the reference time;
wherein the first, second and reference time counters are configured to count at substantially a same frequency.