Patent ID: 7941111

Claim:
A method for detecting an RF signal in a network of RF receivers, wherein the network of RF receivers comprises a plurality of RF receivers connected to a central processing device, the method comprising: receiving the RF signal by a first RF receiver among the plurality of RF receivers; at the first RF receiver: producing first digitized data from the received RF signal, time-stamping the first digitized data to produce first time-stamped data, storing the first time-stamped data in a memory in the first RF receiver, detecting whether a trigger criterion is satisfied based on a characteristic of the received RF signal, and in response thereto: retrieving the first time-stamped data from the memory, processing the retrieved first time-stamped data, transmitting the processed first time-stamped data over the network, and transmitting from the first RF receiver to a second RF receiver in the network a trigger message that includes a time-stamp identifying a time when the first RF receiver detected that the trigger criterion was satisfied; at the second RF receiver: producing second digitized data from the RF signal received by the second RF receiver, time-stamping the second digitized data to produce second time-stamped data, storing the second time-stamped data in a memory in the second RF receiver, detecting the trigger message transmitted by the first RF receiver, and in response thereto, retrieving the second time-stamped data from the memory in the second RF receiver, processing the retrieved second time-stamped data, and transmitting the processed second time-stamped data over the network; noting a time-difference between the processed first time-stamped data from the first RF receiver, and the processed second time-stamped data from the second RF receiver; computing a cross-spectrum between the processed first time-stamped data and the processed second time-stamped data; and multiplying the cross-spectrum with a phase ramp having a slope which corresponds to a difference in time stamps between the processed first time-stamped data and the processed second time-stamped data.