A tracking loop and associated method for tracking a satellite signal in a GNSS receiver and for determining a line-of-sight (LOS) signal from a plurality of satellite signals received by the GNSS receiver from a satellite. One or more first correlators perform a correlation between a code signal derived from one of the received satellite signals and a plurality of corresponding replica code signals to determine a plurality of code correlation sums comprising a prompt code correlation sum, one or more early code correlation sums and one or more late code correlation sums. One or more second correlators correlate the plurality of code correlation sums with a plurality of replica carrier signals, each having a different Doppler frequency offset, to determine, for each of the plurality of code correlation sums, a set of correlation magnitudes at frequencies of the plurality of replica carrier signals. An LOS identification module identifies the LOS signal based on a signal propagation delay corresponding to one or more local maxima within the sets of correlation magnitudes.

Methods, devices, systems, media, and receivers for processing GNSS signals are described. One aspect of the present disclosure provides a method for processing satellite signals of a Global Navigation Satellite System (GNSS), the method comprising: receiving a first GNSS signal transmitted in a first GNSS operational band by a satellite of the GNSS and a second GNSS signal transmitted in a second GNSS operational band by the satellite; tracking the first GNSS signal; generating, from the tracking of the first GNSS signal, tracking parameters for the first GNSS signal; and decoding, at least based on the tracking parameters for the first GNSS signal, the second GNSS signal, wherein the first GNSS operational band is one of L1 band, L2 band or L5 band, and the second GNSS operational band is L6 band.

A position locating system to determine relative position information between a marine vessel and a trailer includes a first GNSS receiver located on one of a marine vessel and a trailer to receive a positioning signal from a positioning satellite, a second GNSS receiver located on the other of the marine vessel and the trailer to receive the positioning signal from the positioning satellite, a registering unit to register a current position of the trailer based on the positioning signal received by the first GNSS receiver when the trailer is stationary, a direction obtaining unit to obtain a direction of the marine vessel, a generating unit to generate correction information in real time based on the current position and the positioning signal received from the positioning satellite by the first GNSS receiver, and a position locator to determine relative position information between the marine vessel and the trailer.

Authentication mechanism is provided to open service signals in Global Navigation Satellite Systems (GNSS), by inverting a plurality of bits in a pseudorandom noise code in a GNSS signal having a predetermined period of a binary bit sequence of N bits. A position of each inverted bit in the binary bit sequence is specified by a serial number generated for each period using a cryptographic pseudorandom number generator, where at least one of the position of the inverted bit and a number of the inverted bits in the period varies period by period. A decryption key is provided to a GNSS receiver, which correlates, using a corresponding cryptographic pseudorandom number generator, the received GNSS signal, and accumulates an amplitude thereof at the inverted bit, thereby determining if the received signal is counterfeit based on the ratio of the inverted bit amplitude with respect to the signal amplitude.

The present invention discloses a high-precision point positioning method and device based on a smartphone. The method of the present invention, which belongs to the technical field of satellite positioning, improves the conventional PPP uncombined positioning model, and only uses original GNSS observation values received by a smartphone to carry out high-precision positioning without GNSS reference stations. The positioning method of the present invention comprises following steps: acquiring original observation values of the smartphone, such as GNSS pseudoranges and carrier phases; after preprocessing the data to decrease part of error influences, generating an uncombined model from the original observation values according to an improved precise point positioning method based on an estimation of double clock biases; determining each satellite observation value weight according to a satellite elevation angle; and carrying out filtering positioning by an improved Kalman filtering method to give a high-precision point positioning result.

A method for generating a feature-based localization map for a global navigation satellite system (GNSS) -based localization and/or a feature-based localization includes generating feature information for the feature-based localization map using at least one GNSS information, generating GNSS-related meta-information that allows inferences to be drawn about a GNSS situation on which the generation of the feature information was based, and assigning the generated GNSS-related meta-information to the generated feature information.

A method for providing time information in a GNSS receiver includes receiving at least one time counter variable from a GNSS satellite. The at least one time counter variable describes a number of time intervals that have passed since a time start value, and a data length of the time counter variable limited to a maximum number of countable time intervals. The method also includes reading an offset variable out of a non-volatile memory held in the GNSS receiver. The offset variable describes a time previously received and reconstructed by the GNSS satellite, and a data length of the offset variable exceeds the data length of the time counter variable. The method further includes carrying out a remainder division of the offset variable with a maximum number given by the data length of the at least one time counter variable in order to determine an offset time counter variable.

Disclosed are methods and apparatuses for transmitting and receiving characteristic information of a GNSS subframe. A method for transmitting and receiving characteristic information of a GNSS subframe, as a method for a first device, may comprise: receiving a subframe including first information, which is characteristic information of the subframe, from a second device; checking a format of the subframe on the basis of the first information; and determining whether to decode data included in the subframe on the basis of the checked format of the subframe.

Aspects of the present disclosure relate to identifying points of interest by generating and storing virtual geofence information that is captured around a physical structure based in part on global positioning system (GPS) data from a plurality of devices that is then processed to identify GPS trajectory and kernel density estimation. Specifically, the techniques include receiving, at the network-based control computer, GPS data from a plurality of devices and grouping the GPS data from the plurality of devices to generate GPS trajectory information for each group of the plurality of devices. Based on the GPS trajectory information, the network-based control computer may calculate kernel density estimation and determine an isoline on a virtual map for the each group of the plurality of devices. By overlaying the isoline data on a geographic coordinate information of a physical structure, the network-based control computer may generate a virtual geofence around the physical structure and store, in a memory, geofence information for the facility.

Techniques for detecting GNSS spoofing using inertial mixing data are disclosed. One or more navigation parameters are determined by at least one GNSS receiver and a plurality of IRS from at least two periods of time. The navigation parameters from the GNSS receiver(s) and the IRS are compared at each time period, and the difference(s) between the compared navigation parameters are further compared to generate at least one differential value. A system can detect GNSS spoofing by comparing the at least one differential value to a suitable threshold. In one aspect each IRS navigation parameter is compared with a corresponding GNSS navigation parameter, wherein the plurality of differential values is mixed before threshold comparison. In another aspect, each IRS navigation parameter is mixed before comparison with a GNSS navigation parameter, and the resulting differential value is then compared against a threshold.