I’m Walking Here!
An ingenious navigation technique makes use of how the human body works to develop an accurate pedestrian navigation system — one whose accuracy has been checked using drone imagery.
Kindred SpiritsIn this article, author Urs Hugentobler looks at the history of laser ranging to navigation satellites, how that ranging has improved the accuracy of the orbits of those satellites, and what the future portends for this important contribution to space geodesy.
Precision on Board
Described are the results of realistic simulations carried out to precisely position a low-Earth-orbit satellite using a source of real-time GPS corrections actually transmitted by a network of geostationary satellites. Even accounting for data outages, 3D positioning accuracies better than a decimeter have been obtained. Precision on board? Not right now but likely coming real soon.
Reflected BlessingsA 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.
Double Take
A diversely polarized antenna array combines signal processing in the spatial and polarization domains for significant improvement in receiver robustness against interference. The C/N0 of line-of-sight components is improved since the receiver can use the power present in the left-hand circularly polarized channels, and also interference mitigation improves.
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.
Precision GNSS for everyoneIn this month’s column, we take a look at some initial efforts to independently process smartphone measurements. How good are the results? Read on.
Getting there more safelyWe discuss how chip-scale atomic clocks can help us navigate more safely by allowing a GNSS receiver to position itself more accurately even with only three satellites in view, and to protect itself by being able to detect a sophisticated spoofing attempt.
Follow Us