A Real-Time Kinematic (RTK) solution is provided to mobile devices having multi-constellation, multi-frequency (MCMF) functionality, in which a single base station may have a baseline much farther than traditional base station and where the high accuracy positioning is achieved in a relatively short period of time. To enable this, embodiments involve modeling of an ionosphere-free carrier phase corresponding to combinations of at least three signals received from one or more satellites. The modeling retains the integer nature of carrier phase ambiguities, thereby allowing for fast convergence in determining the integer ambiguity of the carrier phases.

A Real-Time Kinematic (RTK) solution is provided to mobile devices having multi-constellation, multi-frequency (MCMF) functionality, in which a single base station may have a baseline much farther than traditional base station and where the high accuracy positioning is achieved in a relatively short period of time. To enable this, embodiments involve modeling of an ionosphere-free carrier phase corresponding to combinations of at least three signals received from one or more satellites. The modeling retains the integer nature of carrier phase ambiguities, thereby allowing for fast convergence in determining the integer ambiguity of the carrier phases.

Certain implementations of the disclosed technology may include systems and methods for reducing noise in dual-frequency GNSS signal observation. The method can include: receiving, at a GNSS receiver, a first signal and a second signal. At least the second signal includes noise. The first signal is characterized by a first carrier frequency, and the second signal is characterized by a second carrier frequency. The method includes: down converting, sampling, cross-correlating, accumulating, determining ambiguous instantaneous phases, determining non-ambiguous instantaneous phases, producing normalized non-ambiguous instantaneous first phase samples, constructing a normalized first counter rotation phasor, generating a counter-rotated second observable, applying a low pass filter to remove noise; and outputting the filtered second observable.

Certain implementations of the disclosed technology may include systems and methods for reducing noise in dual-frequency GNSS signal observation. The method can include: receiving, at a GNSS receiver, a first signal and a second signal. At least the second signal includes noise. The first signal is characterized by a first carrier frequency, and the second signal is characterized by a second carrier frequency. The method includes: down converting, sampling, cross-correlating, accumulating, determining ambiguous instantaneous phases, determining non-ambiguous instantaneous phases, producing normalized non-ambiguous instantaneous first phase samples, constructing a normalized first counter rotation phasor, generating a counter-rotated second observable, applying a low pass filter to remove noise; and outputting the filtered second observable.

Techniques are provided for utilizing a mobile device to estimate ionospheric delays in GNSS transmissions. An example method of determining a position of a mobile device includes obtaining a pseudorange measurements and carrier-phase measurements for a satellite at a first frequency band and a second frequency band, determining a bias estimate for the satellite based on a plurality of pseudorange measurements and carrier-phase measurements, determining a delta carrier-phase measurement for the satellite based on the carrier-phase measurements at the first frequency band and the second frequency band, and determining the position of the mobile device based at least in part on the delta carrier-phase measurement, and the pseudorange measurements, the carrier-phase measurements, or both.

A method of and a receiver for mitigating multipath interference in a global navigation satellite system. In accordance with an embodiment, GNSS signals are received from a plurality of satellites in at least two frequency bands. A likelihood indicator is determined which is indicative of how likely the received GNSS signals are affected by multipath interference. In response to the likelihood indicator, all GNSS signals from at least one frequency band of the at least two frequency bands are discounted. The received GNSS signals are processed by taking into account said discounting of all GNSS signals in the at least one frequency band. The discounting may include assigning less weight to the discounted frequency bands or disregarding each of the discounted frequency bands in their entirety.

A method of and a receiver for mitigating multipath interference in a global navigation satellite system. In accordance with an embodiment, GNSS signals are received from a plurality of satellites in at least two frequency bands. A likelihood indicator is determined which is indicative of how likely the received GNSS signals are affected by multipath interference. In response to the likelihood indicator, all GNSS signals from at least one frequency band of the at least two frequency bands are discounted. The received GNSS signals are processed by taking into account said discounting of all GNSS signals in the at least one frequency band. The discounting may include assigning less weight to the discounted frequency bands or disregarding each of the discounted frequency bands in their entirety.

An apparatus control method includes: controlling a first frequency band receive chain, of an apparatus, to alternate being on and off with a first duty cycle, the first frequency band receive chain being configured to measure satellite signals within a first frequency band; determining one or more performance criteria; and controlling, based on the one or more performance criteria, a second frequency band receive chain, of the apparatus, to alternate being on and off with a second duty cycle, the second frequency band receive chain being configured to measure satellite signals within a second frequency band.

Systems and methods for multi-sensor mapping are provided for a multi-sensor device having a range sensor, a location sensor and an orientation sensor that provide range data, location data and orientation data, respectively. The device may be operated in a stationary mode, a mobile ground mode or an airborne mode. The range data, the location data and the orientation data are combined to generate three-dimensional geo-referenced point cloud data.

First information is obtained from a sensing device at a first time. The first information corresponds to a radio signal received at the device from a candidate location. The device is at a first location at the first time. Second information is obtained from the device at a second time. The second information corresponds to a radio signal received at the device from the candidate location. The device is at a second location at the second time. A system determines that a pattern is in each of the first and second information and determines relationships between the candidate location and the device at each first and second location. The system obtains inverses of the relationships and determines estimates of the received radio signals based on the information and inverses. The system measures or estimates energy emitted from the candidate location based on the estimates.