1. A system for determining a mobile object's pose on a surface, the system comprising: an object body comprising a signal sensor and a motion sensor; a drive mechanism configured to move the object body and change the orientation of the object body, so that the object body can have an earlier pose comprising an earlier location and an earlier orientation at an earlier time and a later pose comprising a later location and a later orientation at a later time, a processing unit configured to logically define the surface as a first plurality of logical cells, wherein a given cell in the first plurality of logical cells is defined, at least in part, by a set of three or more nodes having respective pre-defined locations; the signal sensor configured to detect and measure a property of one or more light signals from at least a first signal source and to output data corresponding to a value measured, wherein the signal sensor has a substantially fixed orientation relative to the object body, and the signal sensor has a rotational variability such that a first measure of the property of a light signal at a time, measured when the object body is at a location and has a first orientation is different from a second measure of the property of the light signal at the same time measured when the object body is at the same location and has a second orientation different from the first orientation; the motion sensor configured to measure one or more dead-reckoning properties and to output data corresponding to one or more values of the measured one or more dead-reckoning properties; a reckoning data processing unit in communication with the motion sensor and configured to calculate a change in orientation, a relative direction of travel, and a relative distance of travel between a first time and a second time based at least in part on a portion of the data from the motion sensor output at the second time; a calibration data processing unit configured to calculate a first parameter approximating the rotational variability of the signal sensor and a second parameter relating the property of the signal to a respective location, such that the signal property has an expected measure at the respective location and the expected measure can be determined from the second parameter and the respective location, the first parameter and second parameter calculated based at least in part on an initial pose of the object body at an initial time, at least a portion of the data from the signal sensor at the initial time, data calculated by the reckoning data processing unit at the initial time, at least a portion of the data from the signal sensor at a subsequent time, and data calculated by the reckoning data processing unit at a subsequent time; a cell initialization data processing unit configured to initialize one or more nodes in a set of nodes defining a corresponding cell by calculating an expected measure of the signal property at the respective locations of the one or more nodes, the expected measure calculated based at least in part on the second parameter and the predefined locations of the respective nodes; a localization and mapping data processing unit configured to use a SLAM algorithm to calculate a refined pose approximating a third pose of the mobile object at a third time within a cell having initialized nodes.