Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

The present disclosure generally pertains to systems and methods for providing position information to aircraft using radio-frequency signals. By providing a ground-based solution entirely independent of GPS, systems of the present disclosure can make navigation systems more accurate and robust, enhancing their effectiveness and safety. More precisely, systems of the present disclosure may employ a series of ground-based beacon transmitters to provide coverage across a defined geographic region. Primary beacon transmitters may be used to generate a radio-frequency (RF) signal pulse with a highly regular frequency. A larger number of secondary beacon transmitters may be used to re-transmit these RF signal pulses with a tightly controlled turnaround time. A locating receiver can detect the arrival times of these pulses and use this information, along with stored information about the relative positions of the beacon transmitters, to determine its location.

In one example, a device includes a receiver configured to receive a low-power X band radar transmission, and a transmitter operably coupled to the receiver and configured to transmit an X band transmission in response to receiving the low-power X band radar transmission.

The invention regards to a local navigation system comprising:

a plurality of beacons located in a local environment and being configured to send signals specified to different routes in said local environment;

a plurality of mobile devices, each of them comprising: a client control means,

a wireless communication link configured to receive the signals sent by the beacons;

an output means configured to display/emit navigation guide data;

in which local navigation system the client control means is configured to process the signals received via the wireless communication link and to process this data into navigation guide data outputted on output means of the mobile device,

whereby each route comprised in the local environment is assigned a unitary ID

and whereby each beacon is located in one specific location of the local environment along at least one of said routes, whereby each beacon is configured to send the IDs of all the routes passing along its specific location,

whereby the client control means obtains the route ID to a chosen destination from a destination input device of the local navigation system and/or of the mobile device, and which client control means is configured provide said navigation guide data in interaction with the beacons sending said route IDs of the chosen location. This system allows anonymous navigation in the local environment, possibly in a decentralized system without centralized or wired system components.

A course of a mobile terminal device is estimated. An information processing system (S) includes: a plurality of transmission devices (1a, 1b) capable of transmitting predetermined radio waves; a terminal device (2) capable of receiving the predetermined radio waves; and a management device (3) communicably connected to the terminal device, wherein the terminal device (2) measures an intensity of the radio waves received from each of the plurality of transmission devices (1a, 1b) at intervals of a predetermined time period, and transmits measurement results to the management device (3), and the management device (3) estimates, from the measurement results, a distance from each of the plurality of transmission devices (1a, 1b) to the terminal device (2), and estimates a course of the terminal device (2) from the estimated distances.

Systems and methods for a low-frequency radio navigation system are described. The system may include a transmitter comprising a base coded modulator configured to generate a base modulation and a data coded modulator configured to generate a data modulation; wherein the transmitter radiates a continuous, constant-power chirped-FM spread spectrum signal, comprising: the base modulation; and the data modulation, wherein the data modulation is orthogonal to the base modulation. The system may also include a receiver comprising a digital signal processor, wherein at least one matched filter coupled to the digital signal processor, the at least one matched filter configured to decode said base modulation and data-encoded modulation and provide a correlation function for received signals received from at least three geographically-spaced transmitters.

Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

Systems and methods for a low-frequency radio navigation system are described. The system may include a transmitter comprising a base coded modulator configured to generate a base modulation and a data coded modulator configured to generate a data modulation; wherein the transmitter radiates a continuous, constant-power chirped-FM spread spectrum signal, comprising: the base modulation; and the data modulation, wherein the data modulation is orthogonal to the base modulation. The system may also include a receiver comprising a digital signal processor, wherein at least one matched filter coupled to the digital signal processor, the at least one matched filter configured to decode said base modulation and data-encoded modulation and provide a correlation function for received signals received from at least three geographically-spaced transmitters.

An ultra wideband (UWB) dynamic positioning method and a system thereof are provided. A target UWB device detecting step includes driving a host UWB device to detect whether a target UWB device or at least one first-order seeking UWB device is around the host UWB device, and then a detecting result is generated. A host UWB device operation deciding step includes deciding an operating mode of the host UWB device according to the detecting result. When the target UWB device is around the host UWB device, the operating mode includes calculating a moving direction from the host UWB device to the target UWB device. When there is the first-order seeking UWB device around the host UWB device without the target UWB device, the operating mode includes switching on the first-order seeking UWB device to enter a seeking mode.

Systems and methods for a low-frequency radio navigation system are described. The system may include a transmitter comprising a base coded modulator configured to generate a base modulation and a data coded modulator configured to generate a data modulation; wherein the transmitter radiates a continuous, constant-power chirped-FM spread spectrum signal, comprising: the base modulation; and the data modulation, wherein the data modulation is orthogonal to the base modulation. The system may also include a receiver comprising a digital signal processor, wherein at least one matched filter coupled to the digital signal processor, the at least one matched filter configured to decode said base modulation and data-encoded modulation and provide a correlation function for received signals received from at least three geographically-spaced transmitters.