Abstract: A method for processing GNSS signals comprises obtaining respective output sequences from N correlators for a snapshot of a received GNSS signal, wherein each sequence has K values, and the N correlators correspond to N different delays of a PRN code sequence; computing one or more complex values using the output sequence; computing a reference complex value using the one or more complex values; for each output sequence, computing respective one or more real values using the reference complex value and the respective one or more complex values of the output sequence; and estimating a delay of the received GNSS signal using the one or more real values of the output sequences.

Abstract: A method for receiving and processing GNSS signals is performed by a GNSS receiver featuring a power saving mode. The method comprises, in the power saving mode: receiving and taking a snapshot of a GNSS signal in a duty cycle, wherein the duty cycle is part of a cycle; computing, in the duty cycle, respective correlations between the snapshot and different delays of a PRN code sequence; computing, in the duty cycle, respective frequency spectra of the correlations; estimating, in the duty cycle, a delay and a Doppler shift of the GNSS signal based on the frequency spectra; and reducing power consumption for the rest of the cycle; wherein an accuracy of the estimated delay and the estimated Doppler shift is in a same order of magnitude as an accuracy of a delay and a Doppler shift estimated in a full power mode without reducing power consumption.

Abstract: A method for estimating delays and Doppler shifts of GNSS signals comprises obtaining respective output sequences from N correlators for a snapshot of a received GNSS signal, wherein each sequence has K values, the N correlators correspond to N different delays of a pseudorandom noise, PRN, code sequence, the K values are correlation values at K sampling time points in each sequence, N and K are positive integers. The method further comprises, for each output sequence, obtaining a frequency spectrum by computing a K-point discrete Fourier transform, DFT, of the output sequence; obtaining a N×K matrix using the N frequency spectra; determining at least one peak value in the N×K matrix; and estimating a delay and a Doppler shift of the received GNSS signal using indices of the at least one peak value in the N×K matrix.

Abstract: A system for determining a position of a user in a building includes a control device, a plurality of stationary radio signal transmission devices, a radio signal receiving device, and a signal processing device. The signal processing device determines primary channel impulse responses based on the radio signals received by the receiving device. The signal processing device also determines a secondary channel impulse response based on a secondary radio signal received by the receiving device from a mobile device of a user. The channel impulse responses are evaluated to determine degrees of similarity that indicate how similar a first primary channel impulse response and the secondary channel impulse response are to one another. For each degree of similarity, a distance of the mobile device from the transmission device corresponding to the degree of similarity is determined. A position of the mobile device is determined based on the distances.

Abstract: A system for controlling access to an access-restricted zone in a building includes a transmitting device transmitting a first radio signal, a receiving device for radio signals, a control device and a signal processing device communicatively connected to the receiving and control devices. The signal processing device determines a first channel impulse response based on the first radio signal received by the receiving device and a second channel impulse response based on a second radio signal received by the receiving device. The second radio signal is transmitted from a first mobile electronic device of a first user. The signal processing device determines a degree of similarity by evaluating the first and second channel impulse responses. The degree of similarity indicates how similar the first and second channel impulse responses are to one another. The control device initiates a building action if the degree of similarity meets a specified rule.

Abstract: A system for determining a position of a user in a building includes a control device, a plurality of stationary radio signal transmission devices, a radio signal receiving device, and a signal processing device. The signal processing device determines primary channel impulse responses based on the radio signals received by the receiving device. The signal processing device also determines a secondary channel impulse response based on a secondary radio signal received by the receiving device from a mobile device of a user. The channel impulse responses are evaluated to determine degrees of similarity that indicate how similar a first primary channel impulse response and the secondary channel impulse response are to one another. For each degree of similarity, a distance of the mobile device from the transmission device corresponding to the degree of similarity is determined. A position of the mobile device is determined based on the distances.

Abstract: A system for controlling access to an access-restricted zone in a building includes a transmitting device transmitting a first radio signal, a receiving device for radio signals, a control device and a signal processing device communicatively connected to the receiving and control devices. The signal processing device determines a first channel impulse response based on the first radio signal received by the receiving device and a second channel impulse response based on a second radio signal received by the receiving device. The second radio signal is transmitted from a first mobile electronic device of a first user. The signal processing device determines a degree of similarity by evaluating the first and second channel impulse responses. The degree of similarity indicates how similar the first and second channel impulse responses are to one another. The control device initiates a building action if the degree of similarity meets a specified rule.