Experimental Comparison of Visual and Single-Receiver GPS Odometry

TL;DR

This paper compares visual odometry and GPS odometry for mobile robots, showing GPS can significantly reduce drift and provide reliable relative positioning with a single receiver, especially in challenging environments.

Contribution

The paper introduces a robust single-receiver GPS odometry method and provides an experimental comparison with visual odometry on the same trajectories.

Findings

GPS odometry has 75% lower drift rate than stereo visual odometry.

GPS odometry maintains smooth error signals despite satellite availability.

The method is effective over 1.8 km test trajectories.

Abstract

Mobile robots rely on odometry to navigate through areas where localization fails. Visual odometry (VO) is a common solution for obtaining robust and consistent relative motion estimates of the vehicle frame. Contrarily, Global Positioning System (GPS) measurements are typically used for absolute positioning and localization. However, when the constraint on absolute accuracy is relaxed, time-differenced carrier phase (TDCP) measurements can be used to find accurate relative position estimates with one single-frequency GPS receiver. This suggests practitioners may want to consider GPS odometry as an alternative or in combination with VO. We describe a robust method for single-receiver GPS odometry on an unmanned ground vehicle (UGV). We then present an experimental comparison of the two strategies on the same test trajectories. After 1.8km of testing, the results show our GPS odometry method has a 75% lower drift rate than a proven stereo VO method while maintaining a smooth error signal despite varying satellite availability.