Spread-spectrum receiver with progressive fourier transform

A communications system comprising:

• a plurality of reporting devices,
• each reporting device including:
• a data collection device that is configured to determine a state of one or more sensors, and
• a transmitter that is configured to transmit the state of the one or more sensors about a nominal frequency that is common to the plurality of reporting devices using a spreading code that is common to the plurality of reporting devices;
• wherein
• a code-phase of the spreading code used at each transmitter is independent of the code-phase used at other transmitters of the plurality of devices,
• actual transmission frequencies used by the transmitters of the plurality of reporting devices differ pseudo-randomly about the nominal frequency, and
• each transmitter is configured to transmit the state of the one or more sensors at a rate and duration that are selected to, provide a low likelihood of collision with transmissions from the other transmitters, thereby facilitating discrimination of receptions of the state of the one or more sensors of the plurality of reporting devices at a receiving system that operates asynchronous to any of the transmitters, based on energy detected at each reception frequency and code-phase corresponding to each non-colliding transmission.