SuperLocaliser

Maintained by: David Austin

1.0 Introduction
2.0 Invocation
3.0 Design

1.0 Introduction

The SuperLocaliser is the source (for high-level users) of all localisation information in the DROS system. The idea is that the SuperLocaliser takes care of queries for the robot's position, both in robot (odometric) and world coordinates. In addition, the SuperLocaliser maintains an archive of the robot's odometric and world coordinates for times in the past. The primary purpose of the archive is to find out where the robot was when measurements were taken.

The SuperLocaliser is also responsible for fusing the various estimates of the robot's world position. For example, there may be several localisation methods running, all supplying estimates of the world position of the robot. The SuperLocaliser fuses the supplied estimates.

2.0 Invocation

3.0 Design

This section documents some of the semantics of the operation of the SuperLocaliser and the overall design ideas.

Basic design philosophy:

The SuperLocaliser is responsible for fusing the world position estimates from the localisers. Each localiser should report it's estimate to the SuperLocaliser whenever updated. In general, the fusion of the estimates will be non-trivial. However, if the estimates are reduced to some simple form (e.g. single Gaussian estimate) then fusion is relatively straightforward.
The SuperLocaliser should have a long-term archive of where the robot has been (world and robot coord). Obviously, this should go in the database (though we need to think about caching for efficiency). Clearly recent entries are going to be used much more frequently than historical data.
The SuperLocaliser proxy should be capable of interpolation and extrapolation for short time periods. This way we improve the time resolution of the data provided to clients without increasing the amount of data transmitted. For time intervals of less than 0.1s (for mobile robots) this is probably going to be fine.
The SuperLocaliser should be able to operate without a robot (for access to historical data). Also, it should be possible to change the robot that the SuperLocaliser is connected to and to disconnect the SuperLocaliser from it's robot for a while (for re-starting the low-level robot controller).