Abstract: Described herein are techniques for determining motion characteristics of trains traveling along a train track. In some embodiments, a processor may determine an estimated position of a train using an observed position obtained using one or more UWB antennas and an observed position obtained using one or more GNSS receivers. In some embodiments, a processor may access information specifying a geometry of a train track and determining the position of a train along the train track using an observed position determined using one or more UWB antennas and/or GNSS receiver(s) and the information specifying the geometry of the train track. In some embodiments, a processor may determine estimated positions of a train using the geometry of the train track and at least one observation of the train obtained using one or more positioning devices and select the position of the train from among the estimated positions.

Abstract: Described herein are techniques for determining motion characteristics of trains traveling along a train track. In some embodiments, a processor may determine an estimated position of a train using an observed position obtained using one or more UWB antennas and an observed position obtained using one or more GNSS receivers. In some embodiments, a processor may access information specifying a geometry of a train track and determining the position of a train along the train track using an observed position determined using one or more UWB antennas and/or GNSS receiver(s) and the information specifying the geometry of the train track. In some embodiments, a processor may determine estimated positions of a train using the geometry of the train track and at least one observation of the train obtained using one or more positioning devices and select the position of the train from among the estimated positions.

Abstract: Described herein are techniques for determining motion characteristics of trains traveling along a train track. In some embodiments, a processor may determine an estimated position of a train using an observed position obtained using one or more UWB antennas and an observed position obtained using one or more GNSS receivers. In some embodiments, a processor may access information specifying a geometry of a train track and determining the position of a train along the train track using an observed position determined using one or more UWB antennas and/or GNSS receiver(s) and the information specifying the geometry of the train track. In some embodiments, a processor may determine estimated positions of a train using the geometry of the train track and at least one observation of the train obtained using one or more positioning devices and select the position of the train from among the estimated positions.

Abstract: A system comprising synchronization circuitry, a first interrogator, and a second interrogator. The first interrogator includes a transmit antenna; a first receive antenna, and circuitry configured to generate, using radio-frequency (RF) signal synthesis information received from the synchronization circuitry, a first RF signal for transmission by the transmit antenna, and generate, using the first RF signal and a second RF signal received from a target device by the first receive antenna, a first mixed RF signal indicative of a distance between the first interrogator and the target device. The second interrogator includes a second receive antenna, and circuitry configured to generate, using the RF signal synthesis information, a third RF signal; and generate, using the third RF signal and a fourth RF signal received from the target device by the second receive antenna, a second mixed RF signal indicative of a distance between the second interrogator and the target device.

Abstract: A device comprising: a substrate; a semiconductor die mounted on the substrate; a transmit antenna fabricated on the substrate and configured to transmit radio-frequency (RF) signals at least at a first center frequency; a receive antenna fabricated on the substrate and configured to receive RF signals at least at a second center frequency different than the first center frequency; and circuitry integrated with the semiconductor die and configured to provide RF signals to the transmit antenna and to receive RF signals from the receive antenna.

Abstract: A system and method is disclosed for measuring time of flight to an object. A transmitter transmits an electromagnetic signal and provides a reference signal corresponding to the electromagnetic signal. A receiver receives the electromagnetic signal and provides a response signal corresponding to the received electromagnetic signal. A detection circuit is configured to determine a time of flight between the transmitter and the receiver based upon the reference signal and the response signal.

Abstract: Described herein are systems for radio-frequency (RF) localization. The systems developed by the inventors are designed to improve the accuracy of RF localization to millimeter and sub-millimeter ranges, and additionally, are designed to do so while also limiting manufacturing costs. The RF localization systems developed by the inventors leverage the relatively low costs associated with the manufacturing of printed circuit board assemblies (PCBAs). Manufacturing RF localization devices using PCBAs poses a number of challenges, including large minimum feature size and the presence of surface waves. Described herein are techniques for addressing challenges arising in connection with RF localization devices fabricated using PCBAs. One technique involves the use of slot-fed antennas, which makes the device efficient notwithstanding the large minimum feature size. Another technique involves the use of frequency selective surfaces for suppressing surface waves.

Abstract: A device comprising: a substrate; a semiconductor die mounted on the substrate; a transmit antenna fabricated on the substrate and configured to transmit radio-frequency (RF) signals at least at a first center frequency; a receive antenna fabricated on the substrate and configured to receive RF signals at least at a second center frequency different than the first center frequency; and circuitry integrated with the semiconductor die and configured to provide RF signals to the transmit antenna and to receive RF signals from the receive antenna.

Abstract: A system comprising synchronization circuitry, a first interrogator, and a second interrogator. The first interrogator includes a transmit antenna; a first receive antenna, and circuitry configured to generate, using radio-frequency (RF) signal synthesis information received from the synchronization circuitry, a first RF signal for transmission by the transmit antenna, and generate, using the first RF signal and a second RF signal received from a target device by the first receive antenna, a first mixed RF signal indicative of a distance between the first interrogator and the target device. The second interrogator includes a second receive antenna, and circuitry configured to generate, using the RF signal synthesis information, a third RF signal; and generate, using the third RF signal and a fourth RF signal received from the target device by the second receive antenna, a second mixed RF signal indicative of a distance between the second interrogator and the target device.

Abstract: A device comprising: a substrate; a semiconductor die mounted on the substrate; a transmit antenna fabricated on the substrate and configured to transmit radio-frequency (RF) signals at least at a first center frequency; a receive antenna fabricated on the substrate and configured to receive RF signals at least at a second center frequency different than the first center frequency; and circuitry integrated with the semiconductor die and configured to provide RF signals to the transmit antenna and to receive RF signals from the receive antenna.

Abstract: A device comprising: a radio frequency (RF) coupler comprising input, output, and coupled ports; an antenna capable of receiving RF signals having a first characteristic and transmitting RF signals having a second characteristic, the antenna connected to the RF coupler to provide received RF signals to the input port of the RF coupler and transmit RF signals received at the input port via coupling to signals received at the coupled port; and signal transformation circuitry having an input connected to the output port of the RF coupler to receive RF signals provided by the antenna to the input port and an output connected to the coupled port, the signal transformation circuitry configured to transform first RF signals having the first characteristic received from the output port to second RF signals having the second characteristic and to provide them to the coupled port.

Abstract: A system comprising: an interrogator device, comprising: a first transmit antenna configured to transmit radio-frequency (RF) signals circularly polarized in a first rotational direction; and a first receive antenna configured to receive RF signals circularly polarized in a second rotational direction different from the first rotational direction; and a target device, comprising: a second receive antenna configured to receive RF signals circularly polarized in the first rotational direction and a second transmit antenna configured to transmit, to the interrogator device, RF signals circularly polarized in the second rotational direction.

Abstract: Described herein are techniques for determining motion characteristics (e.g., position, velocity, acceleration, etc.) of one or more trains traveling along a train track, such that train control systems may have the information needed to safely operate the trains at higher speeds and with shorter separation between trains. In accordance with various embodiments, systems and methods described herein may be configured to determine a position, velocity, and/or acceleration of a train traveling along a train track. In some embodiments, the motion characteristics may be determined one or more radio frequency antennas onboard the train, such as in communication with one or more anchor nodes positioned adjacent the train track. Alternatively or additionally, in some embodiments motion characteristics may be determined using one or more one or more inertial measurement units (IMUs) onboard the train.

Abstract: Described herein are techniques for determining motion characteristics (e.g., position, velocity, acceleration, etc.) of one or more trains traveling along a train track, such that train control systems may have the information needed to safely operate the trains at higher speeds and with shorter separation between trains. In accordance with various embodiments, systems and methods described herein may be configured to determine a position, velocity, and/or acceleration of a train traveling along a train track. In some embodiments, the motion characteristics may be determined one or more radio frequency antennas onboard the train, such as in communication with one or more anchor nodes positioned adjacent the train track. Alternatively or additionally, in some embodiments motion characteristics may be determined using one or more one or more inertial measurement units (IMUs) onboard the train.

Abstract: A system comprising synchronization circuitry, a first interrogator, and a second interrogator. The first interrogator includes a transmit antenna; a first receive antenna, and circuitry configured to generate, using radio-frequency (RF) signal synthesis information received from the synchronization circuitry, a first RF signal for transmission by the transmit antenna, and generate, using the first RF signal and a second RF signal received from a target device by the first receive antenna, a first mixed RF signal indicative of a distance between the first interrogator and the target device. The second interrogator includes a second receive antenna, and circuitry configured to generate, using the RF signal synthesis information, a third RF signal; and generate, using the third RF signal and a fourth RF signal received from the target device by the second receive antenna, a second mixed RF signal indicative of a distance between the second interrogator and the target device.

Abstract: A device comprising: a radio frequency (RF) coupler comprising input, output, and coupled ports; an antenna capable of receiving RF signals having a first characteristic and transmitting RF signals having a second characteristic, the antenna connected to the RF coupler to provide received RF signals to the input port of the RF coupler and transmit RF signals received at the input port via coupling to signals received at the coupled port; and signal transformation circuitry having an input connected to the output port of the RF coupler to receive RF signals provided by the antenna to the input port and an output connected to the coupled port, the signal transformation circuitry configured to transform first RF signals having the first characteristic received from the output port to second RF signals having the second characteristic and to provide them to the coupled port.

Abstract: A system and method is disclosed for measuring time of flight to an object. A transmitter transmits an electromagnetic signal and provides a reference signal corresponding to the electromagnetic signal. A receiver receives the electromagnetic signal and provides a response signal corresponding to the received electromagnetic signal. A detection circuit is configured to determine a time of flight between the transmitter and the receiver based upon the reference signal and the response signal.

Abstract: A device comprising: a radio frequency (RF) coupler comprising input, output, and coupled ports; an antenna capable of receiving RF signals having a first characteristic and transmitting RF signals having a second characteristic, the antenna connected to the RF coupler to provide received RF signals to the input port of the RF coupler and transmit RF signals received at the input port via coupling to signals received at the coupled port; and signal transformation circuitry having an input connected to the output port of the RF coupler to receive RF signals provided by the antenna to the input port and an output connected to the coupled port, the signal transformation circuitry configured to transform first RF signals having the first characteristic received from the output port to second RF signals having the second characteristic and to provide them to the coupled port.

Abstract: A device comprising: a substrate; a semiconductor die mounted on the substrate; a transmit antenna fabricated on the substrate and configured to transmit radio-frequency (RF) signals at least at a first center frequency; a receive antenna fabricated on the substrate and configured to receive RF signals at least at a second center frequency different than the first center frequency; and circuitry integrated with the semiconductor die and configured to provide RF signals to the transmit antenna and to receive RF signals from the receive antenna.

Abstract: Radio-frequencies (RF) antennas for use in micro-localization systems are described. The RF antennas described herein may enable localization of objects with high resolutions, such as in the order of one centimeter or less. The RF antennas may be further configured to reduce range error variability across different directions, so that the accuracy of a micro-localization system is substantially the same regardless of the position of the object. An illustrative RF antenna includes an emitting element having first and second conductive traces patterned to reduce the angular impulse delay variability of the RF antenna. The first conductive trace may form a first arm of a spiral and the second conductive trace may form a second arm of the spiral. At least one parameter of the spiral may be selected to reduce the angular impulse delay variability of the RF antenna.