Method and system for detecting an RF signal
View Patent ↗A number of RF receivers are connected in a network. The network is used to transmit communications, data, or both to and from the RF receivers and to synchronize the RF receivers to a common time. Digitized RF data is time-stamped and stored in memory. A trigger circuit in one or more RF receivers determines whether a trigger criterion or criteria has been met. When a trigger criterion or criteria has been met, some or all of the RF receivers in the network transmit select digitized RF data to a central processing device. The central processing device processes the select digitized data to detect if a signal is present.
1. 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.
2. The method of claim 1 , further comprising synchronizing the network of RF receivers to a common time.
3. The method of claim 1 , further comprising combining and coherently processing the processed first time-stamped data transmitted from the first RF receiver, and the processed second time-stamped data transmitted from the second RF receiver, to detect the RF signal.
4. The method of claim 1 , further comprising variably limiting a bandwidth of the first digitized data.
5. The method of claim 1 , further comprising variably limiting a sample rate of the first digitized data.
6. The method of claim 1 , further comprising synchronizing a timing controller in the first RF receiver to a common sense of time in the network according to an IEEE 1588 standard.
7. The method of claim 1 , further comprising aligning in time the processed first time-stamped data from the first RF receiver, and the processed second time-stamped data from the second RF receiver.