Abstract: Reducing power consumption of a receiver in association with estimating the receiver's position using ranging signals. Systems and methods may determine power reduction strategy information, identify a power reduction strategy using the determined power reduction strategy information, and place one or more modules of the receiver into a reduced power state using the identified power reduction strategy. The power reduction strategy may result in powering off different circuitry of the receiver at different times, and under different circumstances.

Abstract: Systems and methods for improving correlation. In at least one system and method, a signal is received and divided into a plurality of slices. Each of the slices is divided into a plurality of sub-slices. A plurality of chips of a PN code are generated, and sub-slice correlation results are generated in parallel. Summation of the sub-slice correlation results generates a slice correlation results, and the accumulated slice correlation results provide a correlation result.

Abstract: Systems and methods for estimating whether a receiver is indoors or outdoors. Certain approaches evaluate data associated with a network of beacons to determine whether the receiver is indoors or outdoors. Such evaluation may include any of determining whether azimuthal angles corresponding to the beacons meet an azimuthal angle condition, determining whether elevation angles corresponding to the beacons meet an elevation angle condition, determining whether signal strengths corresponding to the beacons meet a signal strength condition, and determining whether other measurements associated with the beacons meet other measurement conditions.

Abstract: Determining building weather profile parameters, and correcting an estimated altitude of a receiver using the building weather profile parameters. Systems and methods for estimating an altitude of a receiver using building weather profile parameters may identify one or more weather profile parameters for a building, determine an initial estimate of a receiver's altitude at a floor inside the building, and use the initial estimate and the identified weather profile parameters to determine a corrected estimate of the receiver's altitude at the floor.

Abstract: A position location system comprises transmitters that broadcast positioning signals. Each broadcasted positioning signal comprises a pseudorandom ranging signal. The position location system includes a remote receiver that acquires and measures the time of arrival of the positioning signals received at the remote receiver. During an interval of time, at least two positioning signals are transmitted concurrently by the transmitters and received concurrently at the remote receiver. The two positioning signals have carrier frequencies offset from one another by an offset that is less than approximately twenty-five percent of the bandwidth of each positioning signal of the two positioning signals. Cross-interference between the positioning signals is reduced by tuning the remote receiver to a frequency of a selected signal of the two positioning signals and correlating the selected signal with a reference pseudorandom ranging signal matched to a transmitted pseudorandom ranging signal of the selected signal.

Abstract: Using estimates of a receiver's altitude to determine where a receiver is located and to refine a positioning system's estimate of a receiver's position. Systems and methods determine whether a receiver is inside or outside a building, and may use the determination to confirm or adjust an initial estimate of the receiver's position. Various approaches for making the determination and for assessing the initial estimate of the receiver's position are described.

Abstract: Transmitting information used to estimate a position of a mobile device. This disclosure describes NEAD-based and external location server (ELS)-based positioning systems and methods that determine when an identifier of a mobile device is not known or when the identifier of the mobile device is known but cannot be detected during a search by reference points, and to then provide a location of a reference point that had previous contact with the mobile device instead of an estimated position of the mobile device. The provided location of the reference point can be used by a location server to generate an estimate of mobile device position.

Abstract: Acquiring three-dimensional location information, and using acquired three-dimension location information to locate users and enhance their experience in relation to location-based services.

Abstract: An interference removal filter that includes a combination of a first filter and a second filter, where the first filter passes signals over a frequency range of size B with a variation of less than +/?3 dB, where the peak value of the impulse response of the second filter is displaced in time from the peak value of the impulse response of the first filter by at least 2/B time units, and where the combination of the first filter and the second filter produces a notch in frequency at a frequency location within the frequency range.

Abstract: Systems and methods for improving performance in terrestrial and satellite positioning systems. Signal processing systems and methods are described for selecting, from among a set of codes, certain codes having desired autocorrelation and/or cross-correlation properties. Systems and methods for generating, encoding, transmitting, and receiving signals using the selected codes are also described.

Abstract: Synchronizing the local time of beacons using two way time transfer methods and hardware enabling such methods. Certain systems incorporate receive hardware into beacon circuitry used for transmitting signals so that the beacon can transmit RF signals during transmission periods, and can also receive RF signals from other beacons during non-transmission periods. Receive hardware may be incorporated into beacon circuitry such that the beacon receives an incoming signal and passes that incoming signal to a digital pre-distortion linearization module, which can process that received signal. Methods for controlling whether a beacon transmits RF signals or receives RF signals are also discussed, as are methods for using RF signals received from other beacons for synchronization.

Abstract: Described are systems and methods for estimating a position of receiver using ranging signals from different regions in a network of transmitters. In some embodiments, each ranging signal that exceeds a quality criterion is assigned to one of several defined regions based on a characteristic of that ranging signal. A maximum number of ranging signals per region may be selected and used during trilateration.

Abstract: Systems and methods for estimating error associated with one or more range measurements that are used to estimate the position of a receiver. Estimations of range error may be based on surveyed range errors associated with locations near the position of the receiver. Estimations of range error may alternatively be based on comparisons of actual movement by the receiver to estimated movement between estimates of the receiver's positions.

Abstract: A receiver capable of receiving and a transmitter capable of transmitting LTE (Long-Term Evolution) signals. The receiver is capable of executing firmware to determine position location from a received LTE-like position waveform over signals modulated on a carrier in a positioning frequency band. In one embodiment the positioning signals are transmitted in a positioning band continuously for up to 100 ms, allowing the receiver to integrate the received positioning signals over a period of up to 100 ms. In one such embodiment, the signals can be integrated coherently for up to 60 ms, assuming acceptable stability of the clock in the receiver and further assuming that less than a predetermined amount of Doppler shift has been introduced in the received signal. The number of physical resource blocks (PRB) can be determined to optimize the signal allocation for the available bandwidth.

Abstract: Systems and methods for estimating a position of a receiver within a venue using localized networks of beacons. Certain aspects relate to different configurations of networks. Other aspects relate to estimating the position of the receiver when the receiver approaches an edge of a localized network of beacons.

Abstract: Interference detection and mitigation using maximal ratio combining in the correlation domain. Systems and methods for interference detection and mitigation using maximal ratio combining in the correlation domain may receive a plurality of copies of a positioning signal, compute a plurality of correlation functions using the received positioning signals; weight the plurality of correlation functions using a plurality of weights that are proportional to the quality of the plurality of correlation functions, and generate a combined correlation function by combining the weighted correlation functions.

Abstract: Systems and methods for estimating a position of receiver using sets of two or more transmitters that share one or more common characteristics with each other. The systems and methods may estimate the position of the receiver using signals that were transmitted from a different transmitter in a set of co-located transmitters.

Abstract: Described are methods, systems, means and machine-readable media embodying program instructions for considering water molecules and other mixtures in air when estimating an altitude of a pressure sensor. In at least one implementation, a measurement of humidity is used to compute a gas constant value, and the computed gas constant value is used to estimate an altitude of a pressure sensor. In another embodiment, the measurement of humidity is compared to a threshold condition related to humidity. Depending on the results of the comparison, the measurement of humidity is used to determine the altitude of the pressure sensor.

Abstract: Positioning systems and methods for estimating an altitude of a receiver. In some embodiments, pressure and temperature information from a network of sensors is received by the receiver, and the pressure and temperature information from the network of sensors is used along with pressure information measured at a position of the receiver to estimate the altitude of the receiver.

Abstract: Devices, systems, and methods for sending positional information from transmitters/beacons. In one implementation a transmitter generates a range block including a ranging signal and a hybrid block including positioning data, and sends the range block and hybrid block at different times. A user device may receive signals from a plurality of transmitters and generates position/location information using trilateration and measured altitude information in comparison with transmitter altitude information.