A method of triggering a sensor implanted within a living animal to measure a concentration of an analyte in a medium within the living animal, the method comprising: coupling an inductive element (103, 313, 1302) of an external reader and an inductive element (114, 220) of the sensor within an electrodynamic field; generating field strength data indicative of the strength of the coupling of the inductive element of the external reader and the inductive element of the sensor; determining, based on the field strength data, whether the strength of the coupling of the inductive element of the external reader and the inductive element of the sensor is sufficient for the sensor to perform an analyte concentration measurement and convey the results of the analyte concentration measurement to the external reader; and if the strength of the coupling of the inductive element of the external reader and the inductive element of the sensor is determined to be sufficient, triggering an analyte concentration measurement by the sensor and conveyance of the results of the analyte concentration measurement to the external reader, wherein triggering the analyte concentration measurement by the sensor and conveyance of the results of the analyte concentration measurement to the external reader comprises conveying, using circuitry of the external reader, an analyte measurement command to the sensor, and conveying the analyte measurement command to the sensor comprises modulating, using circuitry of the external reader, the electrodynamic field; decoding, using circuitry of the sensor, the modulation of the electrodynamic field by the circuitry of the external reader; and executing, using the sensor, the analyte measurement command, wherein the execution of the analyte measurement command comprises: generating, using the implanted sensor, analyte measurement information indicative of a concentration of the analyte in the medium within the living animal; and conveying, using circuitry (536, 538) of the sensor, the generated analyte measurement information. coupling an inductive element (103, 313, 1302) of an external reader and an inductive element (114, 220) of the sensor within an electrodynamic field; generating field strength data indicative of the strength of the coupling of the inductive element of the external reader and the inductive element of the sensor; determining, based on the field strength data, whether the strength of the coupling of the inductive element of the external reader and the inductive element of the sensor is sufficient for the sensor to perform an analyte concentration measurement and convey the results of the analyte concentration measurement to the external reader; and if the strength of the coupling of the inductive element of the external reader and the inductive element of the sensor is determined to be sufficient, triggering an analyte concentration measurement by the sensor and conveyance of the results of the analyte concentration measurement to the external reader, wherein triggering the analyte concentration measurement by the sensor and conveyance of the results of the analyte concentration measurement to the external reader comprises conveying, using circuitry of the external reader, an analyte measurement command to the sensor, and conveying the analyte measurement command to the sensor comprises modulating, using circuitry of the external reader, the electrodynamic field; decoding, using circuitry of the sensor, the modulation of the electrodynamic field by the circuitry of the external reader; and executing, using the sensor, the analyte measurement command, wherein the execution of the analyte measurement command comprises: generating, using the implanted sensor, analyte measurement information indicative of a concentration of the analyte in the medium within the living animal; and conveying, using circuitry (536, 538) of the sensor, the generated analyte measurement information. generating, using the implanted sensor, analyte measurement information indicative of a concentration of the analyte in the medium within the living animal; and conveying, using circuitry (536, 538) of the sensor, the generated analyte measurement information.