A method of global navigation satellite system (GNSS) acquisition comprises: computing a line of sight (LOS) angle between a LOS vector of a first satellite and a LOS vector of a second satellite, wherein each LOS vector is the LOS vector between a receiver and the respective satellite; computing a maximum Doppler difference, wherein the maximum Doppler difference is computed between the first satellite and the second satellite based on the LOS angle and a maximum velocity vector attainable by the receiver, wherein Doppler is induced at least by movement of the receiver; determining a final frequency search range based on the maximum Doppler difference computed between the first satellite and the second satellite, wherein the frequency search range includes a center frequency equal to the first frequency at which the first satellite is found; acquiring a GNSS signal from the second satellite at a second frequency.

A positioning device receives positioning signals from multiple positioning satellites respectively provided by multiple positioning systems, selects one or more use systems to be used in a positioning calculation processing among the multiple positioning systems based on a determination of whether a surrounding environment is an environment in which a multipath is likely to occur, and performs the positioning calculation processing by using the positioning signals from the positioning satellites provided by the positioning systems selected as the use systems.

A positioning device receives multiple positioning signals respectively transmitted from multiple positioning satellites, changes a condition of the positioning satellites to be used in a positioning calculation processing based on a determination of whether a surrounding environment is an environment in which a multipath is likely to occur, and performs the positioning calculation processing by using the positioning signals from the positioning satellites that satisfy the condition.

Embodiments relate to a location server, a wireless device and methods performed therein for positioning the wireless device. The wireless device (120) is arranged to perform measurements associated to estimating the position of the wireless device (120), wherein the wireless device (120) is configured to: perform a code phase measurement on a satellite signal between a satellite and the wireless device (120), wherein the code phase measurement indicates a number of cycles of a code phase of the satellite signal, the number comprising a first integer part and a first fractional part; perform a carrier phase measurement on the first fractional part; and send to a location server (130) a report of the code phase measurement and the carrier phase measurement, for estimating the position of the wireless device (120).

A platform with a signal generation unit and a transmitting unit. The signal generation unit is adapted to generate a spreading code sequence. The spreading code sequence has a reference chip with a rising edge and a falling edge. The signal generation unit is adapted to adjust the spreading code sequence to ensure that the rising edge or the falling edge of the reference chip arrives at a Virtual Timing Reference Station, VTRS, on a predetermined time (t.sub.ref,VTRS). The transmitting unit is adapted to engage with the signal generation unit and adapted to transmit the spreading code sequence. Further, a user device for receiving the transmitted spreading code sequence.

The invention discloses a receiver and a method to process navigation signals from one or more GNSS constellation, wherein an observation model and a measurement model allow a direct calculation of the carrier phase ambiguities. More specifically, in a triple frequency implementation, the receiver calculates in turn the extrawidelane, widelane and narrowlane ambiguities. The code and carrier phase biases can also be directly calculated. Thanks to the invention a quicker acquisition and tracking of a precise position, which will also be less noisy than a prior art solution, especially in some embodiments of the invention using a RAIM and/or a gap-bridging function. Also, code smoothing using the Doppler and low latency clock synchronization allow to decrease the noise levels of the precise point navigation solutions.

A signal processing method to avoid deception attack and apparatus for performing the same are provided. The signal processing method includes generating a synthesized signal by receiving a signal from a satellite, detecting a deception signal from the synthesized signal based on tracking information on a signal currently being tracked, separating a normal navigation signal from the synthesized signal in response to the detecting of the deception signal, and computing a normal navigation solution based on the normal navigation signal.

One example includes a passive radar receiver system including an RF receiver front-end to receive a wireless source signal and a reflected signal. An antenna switch of the front-end switches a first antenna to a receiver chain during a first time to generate first radar signal data based on a combined wireless signal comprising wireless source signal and the reflected signal, and switches a second antenna to the receiver chain during a second time to generate second radar signal data based on the combined wireless signal. A signal processor generates source signal data associated with the wireless source signal based on the first and second radar signal data and generates reflected signal data associated with the reflected signal based on the first and second radar signal data, and generates target radar data associated with a target based on the source and reflected radar signal data.

A system and method for determining accurate positions of stationary global navigation satellite system (GNSS) sensors are provided. The method comprises triggering collection of satellite measurements by each of at least a first stationary GNSS sensor and a second stationary GNSS sensor, wherein the satellite measurements are collected per epoch; determining a position of the first stationary GNSS sensor using the satellite measurements collected by the first stationary GNSS; and determining a position of the second stationary GNSS sensor using the satellite measurements collected by the second stationary GNSS and at least the determined position of the first stationary GNSS, wherein the first stationary GNSS sensor is deployed in the vicinity of the second GNSS sensor.

Systems and techniques are provided for performing Quasi-Zenith Satellite System (QZSS) signal acquisition. For example, an example of a method for performing QZSS signal acquisition includes obtaining a modulated message signal using a frequency band and generating, based on an estimated set of signal acquisition parameters associated with an acquired signal, an energy grid of correlation codes. A series of extracted data bytes can be generated for each respective hypothesis of a plurality of hypotheses, based on a location of a peak energy within the energy grid of correlation codes. A correct hypothesis out of the plurality of hypotheses can be determined, wherein the correct hypothesis is associated with a generated series of extracted data bytes that includes a pre-determined header preamble pattern. The modulated message signal can be decoded using an initial code phase associated with the correct hypothesis.