Sequenced Based Direction Finding
It is possible to perform DF using an array of antennas by sequentially switching each of their RF paths to a receiver processing channel. Simultaneously, a Reference antenna provides a constant version of the signal of interest to a second receiver channel. Digital processing of demodulated signals from the two channels is used to generate DF information. Thus, fewer receiver-processing channels (less space, less power, lower cost) are used than for N-channel DF.
The performance of the RF sequencer is critical in this process. CommsAudit sequencer design uses low-loss passive solid-state path-selection switching followed by high-dynamic-range RF amplification – thus, noise figure and dynamic range are optimized so that RF signal fidelity is preserved. Antenna inputs are protected against EMP.
The RF path and digital control circuitry is carefully designed to consistently give high levels of stability; uncertainties created by jitter are minimized.
A CommsAudit Sequencer typically consists of a 2U RF unit handling 2 bands of up to 17 antennas each (array of 16 plus a reference) covering 2 – 80MHz, and a 1U digital control module. The Sequencer operation can be synchronized to external 1pps or 10MHz timing signals.
As with all CommsAudit equipment, Built-In TEst (BITE) features to indicate input and output RF power levels, unit temperature and DC supply health, can be included, as required.