An autonomous mobile work system for performing work in a designated area, the system comprising: a variable reflectivity base station, the base station being configured to change its reflectivity; and an autonomous mobile work device including at least one sensor characterized in that: the work system further comprises a fixed object; the variable reflectivity base station comprises a radar reflector having a variable radar cross section; and the autonomous mobile work system is configured to: provide a location of the variable reflectivity base station to the autonomous mobile work device; change an electromagnetic reflectivity state of the variable reflectivity base station in response to a command from the mobile work device; calculate a first distance between the variable reflectivity base station and the autonomous mobile work device; provide a location of the fixed object to the autonomous mobile work device; calculate a second distance between the fixed object and the autonomous mobile work device; and determine a first location of the autonomous mobile work device based on the provided location of the variable reflectivity base station and the provided location of the fixed object and the calculated distances to the variable reflectivity base station and the fixed object. a variable reflectivity base station, the base station being configured to change its reflectivity; and an autonomous mobile work device including at least one sensor characterized in that: the work system further comprises a fixed object; the variable reflectivity base station comprises a radar reflector having a variable radar cross section; and the autonomous mobile work system is configured to: provide a location of the variable reflectivity base station to the autonomous mobile work device; change an electromagnetic reflectivity state of the variable reflectivity base station in response to a command from the mobile work device; calculate a first distance between the variable reflectivity base station and the autonomous mobile work device; provide a location of the fixed object to the autonomous mobile work device; calculate a second distance between the fixed object and the autonomous mobile work device; and determine a first location of the autonomous mobile work device based on the provided location of the variable reflectivity base station and the provided location of the fixed object and the calculated distances to the variable reflectivity base station and the fixed object. the work system further comprises a fixed object; the variable reflectivity base station comprises a radar reflector having a variable radar cross section; and the autonomous mobile work system is configured to: provide a location of the variable reflectivity base station to the autonomous mobile work device; change an electromagnetic reflectivity state of the variable reflectivity base station in response to a command from the mobile work device; calculate a first distance between the variable reflectivity base station and the autonomous mobile work device; provide a location of the fixed object to the autonomous mobile work device; calculate a second distance between the fixed object and the autonomous mobile work device; and determine a first location of the autonomous mobile work device based on the provided location of the variable reflectivity base station and the provided location of the fixed object and the calculated distances to the variable reflectivity base station and the fixed object. provide a location of the variable reflectivity base station to the autonomous mobile work device; change an electromagnetic reflectivity state of the variable reflectivity base station in response to a command from the mobile work device; calculate a first distance between the variable reflectivity base station and the autonomous mobile work device; provide a location of the fixed object to the autonomous mobile work device; calculate a second distance between the fixed object and the autonomous mobile work device; and determine a first location of the autonomous mobile work device based on the provided location of the variable reflectivity base station and the provided location of the fixed object and the calculated distances to the variable reflectivity base station and the fixed object.