Abstract: A wireless package-mounted sensor system to detect an opening of a package. The system may measure, at each of a plurality of sensors mounted to a plurality of different respective surfaces of the package, an orientation of the surface onto which the sensor is mounted. At least one of the sensors may be mounted to an adjustable surface intended to open the package. An open package test may be executed comprising determining a relative orientation between the sensor mounted to the adjustable surface and another of the plurality of sensors mounted to another of the plurality of different respective surfaces, and determining the package is open if the relative orientation changes from a threshold range indicating a closed state to a threshold range indicating an open state. An indication of the determination that the package is open may be wirelessly transmitting.

Abstract: A hybrid infrared-ultrasound real time location system includes at least one emitter having an infrared transmitter and a plurality of ultrasound transmitters and at least one tag. The tag receives an infrared signal from the infrared transmitter and ultrasound signals from the ultrasound transmitters. The time between the time-of-arrival of the IR signal and the time-of-arrival of each ultrasound signal is calculated and used to measure the respective time-of-flight of each of the US transmissions from the US transmitters to the tag and compute location.

Abstract: A hybrid infrared-ultrasound real time location system includes at least one emitter having an infrared transmitter and a plurality of ultrasound transmitters and at least one tag. The tag receives an infrared signal from the infrared transmitter and ultrasound signals from the ultrasound transmitters. The time between the time-of-arrival of the IR signal and the time-of-arrival of each ultrasound signal is calculated and used to measure the respective time-of-flight of each of the US transmissions from the US transmitters to the tag and compute location.

Abstract: A hybrid infrared-ultrasound real time location system includes at least one base station having an infrared emitter and a plurality of ultrasound emitters and at least one tag. The tag receives an infrared signal from the infrared emitter and ultrasound signals from the ultrasound emitters and a time difference is determined between the time-of-arrival of the IR signal and the time-of-arrival of each ultrasound signal. Based on the time relationship of the respective transmissions of the IR signals and the US signals, the tag can measure the respective time-of-flight of each of the US transmissions from the US emitters to the tag and compute the distance from the base-station.