RTK-VPPP Algorithms in Urban Canyons

Development of Map Aided GPS Algorithms for Vehicle Navigation in Urban Canyons

Vision-based navigation through urban canyons

We address the problem of navigating unmanned vehicles safely through urban canyons in two dimensions using only vision-based techniques. Two commonly used vision-based obstacle avoidance techniques (namely stereo vision and optic flow) are implemented on an aerial and a ground-based robotic platform and evaluated for urban canyon navigation. Optic flow is evaluated for its ability to produce a...

Wall Estimation from Stereo Vision in Urban Street Canyons

Geometric context has been recognised as important high-level knowledge towards the goal of scene understanding. In this work we present two approaches to estimate the local geometric structure of urban street canyons captured from a head-mounted stereo camera. A dense disparity estimation is the only input for both approaches. First, we show how the left and right building facade can be obtain...

Modeling GNSS Signals in Urban Canyons using Visibility Graphs

This paper addresses the problem of modeling and simulating RF-signals captured by receivers of Global Navigation Satellite Systems (GNSS) in urban canyons. The presence of tall buildings in urban canyons often block lines of sight between receivers and GNSS satellites, and therefore signals reach the receivers indirectly, after bouncing off buildings. These multi-path and echo-only effects are...

Improving Accuracy of GNSS Devices in Urban Canyons

This paper addresses the problem of calculating the accurate position of a GNSS device operating in an urban canyon, where lines of sight (LOS) with navigation satellites are too few for accurate trilateration calculation. We introduce a post-processing refinement algorithm, which makes use of a 3D map of the city buildings as well as captured signals from all traceable navigation satellites. T...