A real-time location system including a backbone communication network having a plurality of network access point devices and a real-time location system server, a plurality of monitor devices where each monitor device being located at a location around a facility, each of the plurality of monitor devices being configured to transmit a unique monitor identification code using a secondary transmission technology, each of the monitor identifications codes being mapped to a single location in the facility at which a monitor device is located, each of the monitor devices further being configured to transmit an RF beacon using a first RF protocol, and at least one tag being configured to receive, detect and retransmit the monitor identification code back to at least one of the plurality of monitor devices using a second RF protocol.

An assembly and method for detecting cross bores involving a sewer system and a gas pipe includes an acoustic generator placed within an interior of the sewer system and an acoustic receiver placed either within an interior of the gas pipe or in proximity to an end of the gas pipe. The acoustic generator generates an acoustic signal to transmit through the interior of a sewer pipe of the sewer system. A controller detects, in response to the acoustic receiver hearing the acoustic signal, a cross bore involving the sewer pipe and the gas pipe. A microphone may be placed within the interior of the sewer system at a location remote from the acoustic generator. In this case, the controller determines, in response to the acoustic receiver not hearing the acoustic signal and the microphone hearing the acoustic signal, that a cross bore involving the sewer pipe and the gas pipe is absent.

An assembly and method for detecting cross bores involving a sewer system and a gas pipe includes an acoustic generator placed within an interior of the sewer system and an acoustic receiver placed either within an interior of the gas pipe or in proximity to an end of the gas pipe. The acoustic generator generates an acoustic signal to transmit through the interior of a sewer pipe of the sewer system. A controller detects, in response to the acoustic receiver hearing the acoustic signal, a cross bore involving the sewer pipe and the gas pipe. A microphone may be placed within the interior of the sewer system at a location remote from the acoustic generator. In this case, the controller determines, in response to the acoustic receiver not hearing the acoustic signal and the microphone hearing the acoustic signal, that a cross bore involving the sewer pipe and the gas pipe is absent.

An underwater transmitter may generate underwater pressure waves that encode bits of data. The pressure waves may travel to, and created minute vibrations in, the water's surface. An airborne radar may detect radar signals that reflect from the water's surface. The surface vibrations may modulate the phase of the reflected radar signal. The radar receiver may, based on the variation in the phase of the reflected radar signal, decode the data that was initially encoded in the underwater pressure waves. The underwater pressure waves may be frequency modulated, such as by orthogonal frequency-division multiplexing. Alternatively, the surface vibrations may be detected by a camera, interferometer or other light sensor. Alternatively, the pressure waves may propagate through a media other than water. For instance, the pressure waves may propagate through bodily tissue, or may propagate through oil or a liquid fracking mixture in an oil or gas well.

An underwater transmitter may generate underwater pressure waves that encode bits of data. The pressure waves may travel to, and created minute vibrations in, the water's surface. An airborne radar may detect radar signals that reflect from the water's surface. The surface vibrations may modulate the phase of the reflected radar signal. The radar receiver may, based on the variation in the phase of the reflected radar signal, decode the data that was initially encoded in the underwater pressure waves. The underwater pressure waves may be frequency modulated, such as by orthogonal frequency-division multiplexing. Alternatively, the surface vibrations may be detected by a camera, interferometer or other light sensor. Alternatively, the pressure waves may propagate through a media other than water. For instance, the pressure waves may propagate through bodily tissue, or may propagate through oil or a liquid fracking mixture in an oil or gas well.

An underwater communications network may include spaced apart nodes on a bottom of a body of water. The underwater communications network may also include fiber optic cabling connecting the spaced apart nodes. Each node may include a frame, a node short-range navigation device carried by the frame, and an unmanned underwater vehicle (UUV) carried by the frame after delivering a fiber optic cable along a navigation path from an adjacent node. The UUV may be configured to cooperate with the node short-range navigation device during an end portion of the navigation path adjacent the frame.

A range-finding and/or object-positioning system comprises one or more target devices; one or more reference devices communicating with said one or more target devices via one or more wireless signal sets, each wireless signal set comprising at least a first-speed signal having a first transmission speed and a second-speed signal having a second transmission speed, and the first transmission speed being higher than the second transmission speed; and at least one processing unit performing actions for determining at least one distance between one target device and one reference device based on the time difference between the receiving time of the first-speed signal and the receiving time of the second-speed signal of the wireless signal set communicated between said reference and target devices.

Techniques for calculating a sound received at a plurality of distances from an unmanned aerial vehicle (UAV) may be provided. For example, during delivery, the UAV may be associated with a sensor to obtain first sound information that corresponds to the sound generated by the UAV. A sensor associated with a landing marker may obtain second sound information about the sound generated by the UAV during flight and delivery of a payload to a location associated with the landing marker. In embodiments, the first sound information and the second sound information may be utilized to calculate sound metrics for the sound generated by the UAV and determine the sound received at a plurality of distances from the UAV during flight.

An inexpensive acoustic beacon-type system suitable for the self-localization of one or more submergable secondary vehicles such as AUVs. A single beacon in a primary system periodically transmits an acoustic signal to the secondary vehicle. The acoustic signal is passively received by at least two receivers such as an AUV-mounted ultra-short baseline (USBL) array, which enables multiple vehicles to localize using just a single beacon. A controller (i) maintains time-synchronization with the primary system, (ii) develops a range estimate signal from measurements of received signals from at least two receivers and (iii) develops an azimuth-inclination estimation of likeliest angle-of-arrival of the primary signals, wherein the controller utilizes a plurality of coordinate frames to provide an estimate of secondary system location.

Described is an improved active-beacon/passive-listener time difference of arrival navigation system that relies on the multiple beacons to transmit uncoded acoustic pulses of a same frequency that propagate in the system at a same time for high-speed device tracking. Listening devices may receive multiple encoded radio frequency pulses (RF) prior to a single acoustic pulse, and then resolve which RF pulse corresponds to the acoustic pulse using triangulation techniques.