Patent ID: 8570150

Claim:
A system comprising: a plurality of sensors, each sensor comprising a transmitter configured to transmit sensor data using a spread spectrum encoded pulse comprising modulated spread sensor data, wherein each sensor further comprises a direct sequence layered spreader configured to output a nested multi-level layered pseudo-noise spreading code that is a product of a first pseudo-noise code multiplied by a second pseudo-noise code, the sensor further comprising a multiplier configured to multiple sensor data by the nested multi-level layered pseudo-noise spreading code to produce the spread sensor data; a plurality of mobile nodes, wherein each of the plurality of mobile nodes has a known location and comprises a spread spectrum receiver configured to receive spread spectrum encoded pulses and determine a time of arrival of the spread pulse; and a location calculation unit in communication with each of the plurality of mobile nodes and configured to determine a location of any one of the plurality of sensors using time of arrival information of a transmission from the any one of the plurality of sensors wherein the transmission is received by at least three of the plurality of mobile nodes wherein the spread spectrum receiver of each of the plurality of mobile nodes comprises a layered despreader, wherein the direct sequence layered spreader comprises: an A code generator configured to generate, at a clock rate equal to a chip rate of the first pseudo-noise code, the first pseudo-noise code having a length of P A chips; a B code generator configured to generate at a clock rate equal to 1/P A of the chip rate of the first pseudo-noise code, the second pseudo-noise code having a length of P B chips, wherein “\” is mathematical division.