A method for location finding includes detecting a respective phase difference between the received radio signals that are associated with each of the multiple antennas of each of the fixed transceivers. One or more respective angles are computed between each of the fixed transceivers and the mobile transceiver based on the respective phase differences. Location coordinates of the mobile transceiver are found based on the angles and the transmit locations of the transmitters.

A radar assembly for receiving signals at spaced frequencies from an unknown transmitting source comprising a receiver operative to receive signals; the receiver comprising a series of channels, each channel comprising a low pass filter configured to allow passage of a signal from an unknown transmitting source, an analog to digital converter configured to transform the signal from the unknown transmitting source to a digital signal, a Hilbert transform configured to transform the digital signal from the unknown transmitting source into a single sideband signal, a Fourier transform configured to transform the single sideband signal into a plurality of regularly spaced frequency samples, and an inverse Fourier transform for extracting regularly spaced frequency samples; whereby extracted pulses form a train of pulses that are inputted into an imager which utilizes synthetic aperture radar to form an image of the area of interest containing the unknown transmitting device and method thereof.

A radar assembly for receiving signals at spaced frequencies from an unknown transmitting source comprising a receiver operative to receive signals; the receiver comprising a series of channels, each channel comprising a low pass filter configured to allow passage of a signal from an unknown transmitting source, an analog to digital converter configured to transform the signal from the unknown transmitting source to a digital signal, a Hilbert transform configured to transform the digital signal from the unknown transmitting source into a single sideband signal, a Fourier transform configured to transform the single sideband signal into a plurality of regularly spaced frequency samples, and an inverse Fourier transform for extracting regularly spaced frequency samples; whereby extracted pulses form a train of pulses that are inputted into an imager which utilizes synthetic aperture radar to form an image of the area of interest containing the unknown transmitting device and method thereof.

To provide a laser distance measuring apparatus which can increase the measurement frequency per unit time by suppressing the increase in the data amount expressing the measurement time, while ensuring the distance measurement precision and the measurable distance. A laser distance measuring apparatus measures, with a time resolution, a light receiving time which is a time from a time point when the laser beam generating unit emits the laser beam to a time point when the light receiving unit outputs the light receiving signal; calculates an object distance which is a distance to the object, based on the measurement result of the light receiving time by the time measuring device; and changes the time resolution of the time measuring device used for calculation of the object distance, based on detection information.

To provide a laser distance measuring apparatus which can increase the measurement frequency per unit time by suppressing the increase in the data amount expressing the measurement time, while ensuring the distance measurement precision and the measurable distance. A laser distance measuring apparatus measures, with a time resolution, a light receiving time which is a time from a time point when the laser beam generating unit emits the laser beam to a time point when the light receiving unit outputs the light receiving signal; calculates an object distance which is a distance to the object, based on the measurement result of the light receiving time by the time measuring device; and changes the time resolution of the time measuring device used for calculation of the object distance, based on detection information.

A method of increasing reliability of a wireless radio includes: creating a first waveform at a first center frequency of an encoded data stream using a first wireless radio; creating a second waveform at a second center frequency of the encoded data stream using the first wireless radio; combining the first waveform and the second waveform into a composite waveform with redundant data streams at different center frequencies using the first wireless radio; wirelessly transmitting the composite waveform using the first wireless radio; wirelessly receiving the composite waveform; filtering the received composite waveform using a first filter band; digitizing the received composite waveform using the second wireless radio; demodulating the digitized composite waveform into a first data stream and a second data stream with the second wireless radio; and creating a third data stream representative of the encoded data stream.

A radio-frequency method for range finding includes modulating a reference signal having an intermediate frequency to a downlink signal having a carrier frequency using a clock signal. The downlink signal is transmitted to a tag using a transceiver. An uplink signal backscattered front the tag is received and demodulated using the clock signal. The uplink signal has a frequency that is a harmonic of the carrier frequency. A distance between the tag and the transceiver is calculated based on a phase of the demodulated uplink signal. A system for range finding includes a transceiver and a processor. The transceiver modulates a reference signal to downlink signal and transmits the downlink signal. The transceiver receives and demodulates an uplink signal. The processor is configured to receive the demodulated uplink signal and calculate a distance between the tag and the transceiver using a phase of the demodulated uplink signal.

A system and method of improving data link performance between two or more wireless data transceivers includes: clipping and inverting the data components of a communication signal which are calculated to cause non-linear saturation effects in the downstream power amplifier; delaying a first time series to align the first time series with the clipped and inverted data components of a second time series; adding the clipped and inverted data components of the second time series to the delayed first time series to obtain a modified composite waveform; creating a sacrificial band containing principal energy of the clipped and inverted data components of the second time series; harvesting the principal energy of the sacrificial band to obtain an optimized composite waveform; and amplifying the optimized composite waveform with the downstream power amplifier of one or more of the two or more wireless data transceivers.

Disclosed are systems, devices and methods for determining a range estimate between two Bluetooth enabled devices based, at least in part, on round trip phase measurements of wireless signals transmitted between the devices. In one example, phase estimates between a single antenna of a first device and each element within the antenna array of a second device may be used to determine a residual range between the first device and the second device. In addition, an Angle of Arrival (AoA) may also be used to determine a two dimensional or three dimensional position of the second device.

Apparatus and methods are presented for synchronising a slave device signal to a reference timebase, in situations where the slave device lacks knowledge of the propagation delay for signals from the reference device, e.g. if the positions of one or both of the devices are unknown or classified, or the inter-device signal propagation distance is otherwise a-priori unknown. Reference signal propagation delay is determined using an exchange of signals between the devices, with each device using a differencing procedure for eliminating effects of receiver line bias and other hardware delays. In another aspect an exchange of signals between the devices is used to detect a time residual arising from an inaccurate propagation delay estimate. The synchronisation methods can be applied to a plurality of slave devices for providing a synchronised location network. In certain embodiments signals are transmitted wirelessly, while in other embodiments they are transmitted via a fixed line.