An apparatus for determining a distance to an object is provided. The apparatus includes a first transceiver configured to transmit a first radio frequency signal. Further, the apparatus includes a second transceiver configured to transmit a second radio frequency signal in response to receiving the first radio frequency signal. The apparatus additionally includes a processing circuit configured to determine the distance to the object based on a transmission time of the first radio frequency signal and a reception time, at the first transceiver, of a reflected component of the second radio frequency signal that is reflected by the object.

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.

A method for finding an orthogonal direction of a radiation source with respect a digitally optimized interference pattern of a first fixed electromagnetic element and a second fixed electromagnetic element has been established. Determining a direction of a radiation source allows for dynamic control of moving object.

A communications system, including at least one tag and a plurality of beacons. The tags are configured to detect beacon advertisement messages, initiate a connection with at least one of the plurality of and transmit a Constant Tone (CT) to the at least one of the plurality of beacons. The tag is further configured to determine a location thereof based on the sampled CT from both the beacon and the tag and then report the location via the one of the beacons and/or an access point. Phase ranging mitigation techniques which include hop duplication, hop interpolation and ADC DC offset correction are employed so as to provide more accurate ranging values even in the case where there are many other devices in local proximity and which are competing for use of the same RF channels as those used by the tags and beacons.

A communications system, including at least one tag and a plurality of beacons. The tags are configured to detect beacon advertisement messages, initiate a connection with at least one of the plurality of and transmit a Constant Tone (CT) to the at least one of the plurality of beacons. The tag is further configured to determine a location thereof based on the sampled CT from both the beacon and the tag and then report the location via the one of the beacons and/or an access point. Phase ranging mitigation techniques which include hop duplication, hop interpolation and ADC DC offset correction are employed so as to provide more accurate ranging values even in the case where there are many other devices in local proximity and which are competing for use of the same RF channels as those used by the tags and beacons.

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 causing the composite waveform to produce non-linear distortion to optimize the harvested principal energy.

A method of processing times-of-arrival (TOAs), some representing emitted pulses by an emitter and generated from a pulse pattern having a fixed greatest common divisor pulse repetition interval (GPRI), the method including: creating pulse trains each including an initial TOA and a vector of added TOAs, and a corresponding pulse index vector mapping the TOA vector into the pulse pattern consistent with a known TOA tolerance and viable with a known GPRI range of the emitter type; and walking, for each pulse train, each next TOA after the added TOAs, and each next index mapping the next TOA into the pulse pattern, including checking if the pulse train extended by the next TOA and next index is consistent with the TOA tolerance, checking if the extended pulse train is viable with the GPRI range, and if both checks pass, adding the next TOA and next index to the pulse train.

A long range navigation system may include radio frequency (RF) transmitter stations at fixed geographical locations, each having an RF transmitter and an RF modulator coupled to the RF transmitter, and configured to generate a direct sequence spread spectrum (DSSS) RF signal being spectrally shaped so that 99% of power from the RF transmitter is within the frequency range of 90-110 KHz. Movable RF receiver units each include an RF receiver and a demodulator coupled to the RF receiver configured to demodulate the DSSS RF signal to determine a position of the movable RF receiver unit.

A method of creating a dynamically sharp location based filter includes: placing a moving object containing two or more antennas used for direction finding of a radiation source within a anechoic testing chamber; moving one or more radio transmitters within the anechoic chamber relative to a future spatial location, angle, and/or position of the moving object over a defined time; record an expected angle of arrival of one or more signals of the one or more radio transmitters with respect to the future spatial location, angle, and/or position of the moving object over the defined time; and program a filter within the moving object based on the recorded expected angle of arrival of the one or more signals.

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.