TAG: multipath

Innovation: Position estimation using non-line-of-sight GPS signals

March 15, 2017By and
FIGURE 9.  Normalized overall correlation with contributions from all satellites, including the satellite mirror-image of PRN 5.

Reflected Blessings.
A technique developed by researchers at the University of Illinois at Urbana-Champaign distinguishes a reflected non-line-of-sight (NLOS) signal of a particular satellite from the LOS signal and characterizes the NLOS signal as coming from a virtual mirror-image satellite in the direction of the signal reflection point. By using information on the position and orientation of the reflector, the NLOS signal can be treated as an additional LOS signal. read more

Interference mitigated with CRP and dual-polarized antennas: Free webinar

January 30, 2017By
February cover story.

Two new topic areas and presentations have been added to this Thursday’s free webinar on Signal Interference: Detection and Mitigation. The speakers will explore anti-jamming protection with controlled radiation pattern antennas (CRPAs) and with dual-polarized antennas. The latter topic is also the cover story for the February issue, which demonstrated a significant improvement in positioning accuracy and robustness against interference... read more

Innovation: Correlator beamforming for low-cost multipath mitigation

January 13, 2017By , and
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GNSS Pest Control
A new solution for GNSS multipath employs a multi-element antenna with RF signal switching and a single front end to reduce complexity, power consumption and cost. Correlator beamforming, initially used in the 2.4 GHz frequency band where it has proven effective at mitigating multipath in heavy industrial environments, has been successfully adapted for GNSS use. read more

UK startup Focal Point offers smartphone positioning technologies

December 19, 2016By
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U.K.-startup Focal Point Positioning has unveiled two new positioning technologies. S-GPS and D-Tail represent step changes in consumer GPS processing and smartphone indoor positioning, the company said. S-GPS is a new signal processing, sensor fusion and machine learning scheme that dramatically improves the accuracy and availability of satellite-based positioning signals, the company said. The patent-pending S-GPS technology provides increased sensitivity... read more

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Collecting Points in Difficult Environments with the JAVAD TRIUMPH-LS

August 12, 2015By
A TRIUMPH-LS collecting a point under tree canopy.

By Matt Johnson Fundamental in the determination of GNSS solutions is resolving the correct number of full cycles of the carrier signal (so-called fixing ambiguities) in order to resolve the ambiguity differences between the base and the rover. Distances measured from GNSS receivers contain errors caused by inaccuracies in the satellite and receiver clocks, the satellite orbits, and by the... read more

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Street Smart: 3D City Mapping and Modeling for Positioning with Multi-GNSS

July 1, 2015By
Figure 1. Example of the GNSS signal propagation using ray-tracing and a 3D building map.

A particle-filter-based positioning method using a 3D map to rectify the errors created by multipath and non-line-of-sight signals on the positioning result delivered by a low-cost single-frequency GPS receiver takes a multi-GNSS approach, using the combined signals of GPS, GLONASS and QZSS. The method outperforms conventional positioning in availability and positioning accuracy. It will likely be fused with other sensors in a future pedestrian navigation application. read more

Powerful RTK with Six Separate Engines

June 19, 2015By
Screen anatomy — RTK v6.

By Matthew D. Sibole A little more than a year ago, I became a part of a team of surveyors from across the country to offer testing and input on new technology and programing coming out of JAVAD GNSS. It has been a great honor to work along with Dr. Javad Ashjaee, the other surveyors and Javad’s staff at JAVAD GNSS. Why Javad chose me,... read more

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Galileo E1, E5a Performance for Multi-Frequency, Multi-Constellation GBAS

April 1, 2015By
Pullen-Galileo-O

Analysis of new Galileo signals at an GBAS compares noise and multipath in their performance to GPS L1 and L5. Even after smoothing, Galileo signals perform somewhat better than GPS and are less sensitive to the smoothing time constant. read more