Systems, methods, and apparatuses for determining the distance between two positions are disclosed. The system includes a correlator, a first receiver, and a second receiver. The first and second receivers each include: an antenna, a steering mechanism, and a processor. The steering mechanism steers the antenna in an azimuthal direction and an elevation direction. The processor is configured to (i) control the steering mechanism, (ii) receive data recorded by the antenna from a plurality of sources, (iii) time-stamp the data recorded by the antenna, and (iv) control the transmission of the time-stamped data to the correlator. The correlator is configured to receive the time-stamped recorded data from the first receiver and the second receiver, and calculate a distance between the first receiver and the second receiver based thereon.

A system and method for locating radio-frequency identification tags within a predetermined area. The method can incorporate sub-threshold superposition response mapping techniques, alone, or in combination with other methods for locating radio-frequency identification tags such as but not limited to time differential on arrival (TDOA), frequency domain phase difference on arrival (FD-PDOA), and radio signal strength indication (RSSI). The system can include a plurality of antennas dispersed in a predefined area; one or more radio-frequency identification tags; a radio-frequency transceiver in communication with said antennas; a phase modulator coupled to the radio-frequency transceiver; and a system controller in communication with said transceiver and said phase modulator. Calibration techniques can be employed to map constructive interference zones for improved accuracy.

According to one embodiment, a radio wave information management system includes an information stored unit, a radio wave information determination unit, and a route setting unit. The information stored unit stores radio wave information, and location information and time information associated with the radio wave information. The radio wave information determination unit sets reliability information for the radio wave information based on at least one of the location information and the time information. The route setting unit sets a route of a mobile object based on the reliability information.

A system is provided for resolving ambiguity in a phase measurement used in a distance estimation for an object. The system includes a transmitter for transmitting RF signals from an object location. The system includes measurement equipment for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phases at different frequencies between the transmitted RF signals and the corresponding received RF signals. The system includes a processor. The processor is configured to calculate normalized phases from the plurality of measured phases. The processor is configured to perform an intra-frequency ambiguity resolution process that resolves an ambiguity for the normalized phases for a single frequency using an ambiguity factor. The processor is configured to perform an inter-frequency ambiguity resolution process that resolves an ambiguity for the normalized phases across multiple tones using a characteristic curve to provide a resolved phase measurement for the distance estimation.

A system, method, and computer program product are provided for estimating a distance to an object. The system includes a transmitter for transmitting RF signals from a location of an object. The system further includes measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals. The system also includes a processor. The processor is configured to calculate normalized phases from the plurality of phase differences. The processor is further configured to calculate corrected phases by resolving one or more ambiguities from the normalized phases. The processor is also configured to obtain a characteristic curve using the corrected phases. The processor is additionally configured to provide an estimate of the distance based on the characteristic curve and the corrected phases.

A system, method, and computer program product are provided for estimating a distance to an object. The system includes a transmitter for transmitting RF signals from a location of an object. The system further includes measurement equipment, including a receiver, for receiving the transmitted RF signals as corresponding received RF signals and measuring a plurality of phase differences at different frequencies between the transmitted RF signals and the corresponding received RF signals. The system also includes a processor. The processor is configured to calculate corrected phases by resolving one or more ambiguities from the plurality of phase differences. The processor is further configured to obtain a characteristic curve using the corrected phases. The processor is also configured to provide an estimate of the distance based on the characteristic curve and the corrected phases.

A system, method, and computer program product are provided for estimating a distance. The system includes a Radio Frequency Identifier (RFID) reader. The system further includes an RFID tag. The system also includes measurement equipment for measuring a plurality of phase differences at different frequencies between transmitted Radio Frequency (RF) signals from the RFID reader and corresponding received RF signals at the RFID tag. The system additionally includes a processor. The processor is configured to calculate normalized phases from the plurality of phase differences. The processor is further configured to calculate corrected phases by resolving one or more ambiguities from the normalized phases. The processor is also configured to obtain a characteristic curve using the corrected phases. The processor is additionally configured to provide an estimate of the distance based on the characteristic curve and the corrected phases.

A system to track personnel includes an antenna array associated with a first node to communicate with a second node; and processor circuitry. The processor circuitry to: determine a plurality of positions of the second node; determine a distance between the first node and the second node; determine a bearing between the first node and at least one of the positions; and determine a direction for the first node based on the bearing.

Robotic units may operate in a workspace that is shared with human workers. In order to safeguard the workers, operation of a robotic unit may be inhibited when a worker is near the robotic unit. In order to determine the position of the worker and thereby determine the proximity of the worker and the robotic unit, a time-of-flight measurement is performed to determine the distance of the worker from each of multiple reference locations within or about the workspace. A circular bounding area is defined around each reference location based on the determined distances. A bounded position area is identified as the intersection of the circular bounding areas. The worker is then indicated as being within the bounded position area.

Embodiments for performing access point position determination using crowd sourcing are generally described herein. In some embodiments, a range report request is received, by at least one mobile device, from a network entity for determining a position of a plurality of access points (APs). The at least one mobile device performs range measurements on each of the plurality of APs at different locations. A range report associated with the range measurements performed on each of the plurality of APs is sent to the network entity by the at least one mobile device.