A method includes sending, by a master beacon device and one or more beacon repeater devices, ultra-wideband (UWB) beacon frames. The UWB beacon frames are transmitted as interleaved pairs of UWB beacon frames. Each interleaved pair includes a first UWB beacon frame and a second UWB beacon frame. For each interleaved pair, the first UWB beacon frame and the second UWB beacon frame are transmitted with a master time delay. The method further includes receiving, by one or more tag devices, at least one of the interleaved pairs of UWB beacon frames.

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.

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.

In an embodiment a real-time location method includes sending, by a master beacon device and one or more beacon repeater devices, ultra-wideband beacon frames, wherein the ultra-wideband beacon frames are transmitted as interleaved pairs of ultra-wideband beacon frames, wherein each interleaved pair is sent either from the master beacon device or the one or more beacon repeater devices, wherein each interleaved pair includes a first ultra-wideband beacon frame and a second ultra-wideband beacon frame, and wherein, for each interleaved pair, the first ultra-wideband beacon frame and the second ultra-wideband beacon frame are transmitted with a master time delay, receiving, by one or more tag devices, at least one of the interleaved pairs of ultra-wideband beacon frames, receiving, by the one or more beacon repeater devices, at least one of the interleaved pairs of ultra-wideband beacon frames, receiving, by one of a plurality of tag response receptor units, at least one of the interleaved pairs of ultra-wideband beacon frames, sending, by the one or more tag devices, ultra-wideband tag response frames and receiving, by the one of the plurality of tag response receptor units, at least one of the ultra-wideband tag response frames.

In an embodiment a real-time location method includes sending and receiving ultra-wideband frames using an exchange protocol based on an ultra-wideband frame format, wherein the exchange protocol defines a location rate frame format including a beacon section having a series of time slots associated to at least one frame of interleaved pairs of beacon frames, wherein a first beacon frame and a second beacon frame of each pair are separated in time by a master time delay, and wherein, between time slots assigned to the beacon frames of an opening pair having an initial one of the beacon frames within the beacon section, an array of time slots is respectively assigned to the first beacon frames of the remaining pairs, and a tag response section including a sequence of time slots associated to tag response frames.

In an embodiment a real-time location method includes sending and receiving ultra-wideband frames using an exchange protocol based on an ultra-wideband frame format, wherein the exchange protocol defines a location rate frame format including a beacon section having a series of time slots associated to at least one frame of interleaved pairs of beacon frames, wherein a first beacon frame and a second beacon frame of each pair are separated in time by a master time delay, and wherein, between time slots assigned to the beacon frames of an opening pair having an initial one of the beacon frames within the beacon section, an array of time slots is respectively assigned to the first beacon frames of the remaining pairs, and a tag response section including a sequence of time slots associated to tag response frames.

A device is disclosed. The device may include an antenna, which antenna may receive a ranging signal encoding timing information for one or more of positioning, navigation, and timing. The ranging signal may include a first pulse of a pulse group, a second pulse of the pulse group, and an inter-pulse interval between a start of the first pulse and a start of the second pulse. The device may include a processor, which processor may identify a transmitter of the ranging signal at least partially responsive to the inter-pulse interval.

A method is disclosed. In various examples, the method may include receiving an instruction for generating a signal comprising a ranging signal and a data signal. The method may also include transmitting, via a terrestrial transmitter for transmitting radio waves having encoded messaging information and timing information for one or more of positioning, navigation and timing, the signal at least partially responsive to the instruction. The signal may include a pulse group comprising a number of ranging pulses and a number of data pulses subsequent to the number of ranging pulses. Respective ones of the number of data pulses may have a phase of either a positive-going phase or a negative-going phase. Information may be encoded using the either positive-going phases or negative-going phases of the data pulses.

A method is disclosed. In various examples, the method may include receiving an instruction for generating a signal comprising a ranging signal and a data signal. The method may also include transmitting, via a terrestrial transmitter for transmitting radio waves having encoded messaging information and timing information for one or more of positioning, navigation and timing, the signal at least partially responsive to the instruction. The signal may include a pulse group comprising a number of ranging pulses and a number of data pulses subsequent to the number of ranging pulses. Respective ones of the number of data pulses may have a phase of either a positive-going phase or a negative-going phase. Information may be encoded using the either positive-going phases or negative-going phases of the data pulses.

A device is disclosed. In one or more examples, the device may include an antenna to receive a signal comprising a ranging signal and a data signal. The signal may encode timing information for one or more of positioning, navigation, and timing. The signal may include a first pulse having a first start time and a second pulse having a second start time. The second start time may be an integer number of inter-pulse intervals plus an encoding delay after the first start time. The encoding delay may encode data. The device may include a processor to obtain the data responsive to the encoding delay.