The allowable transmission spectrum of US Navy radars is being heavily utilized by other services like telecommunication systems which is causing many interference problems between the radars and the non-radar services when the radars operate in a littoral environment. In addition, many Navy radars are being operated in close proximity thereby causing in-band interference between radars. The result is that legacy radars are required to use emission control in many littoral environments, which significantly limits the radars' capability and usefulness. Reducing the spectral spread of the radar emissions can alleviate some of the interference problems, both from in-band radars and from the telecommunication services. The goal of this spectrally clean effort is to develop and implement waveforms that constrain their energy down to a -100 dB level within an instantaneous bandwidth of 20 MHz. The basic cardinal-series sampling expansion is unacceptable because it induces leading and trailing timedomain edges of the pulse that continue for a long time. Moreover, the transmitter would be forced to emit very little energy for long periods of time, thereby reducing the efficiency of a transmit-receive module. However, a significant reduction in the leading and trailing edges has been achieved with the GWS function, but at the cost of increasing the bandwidth and the near-in time sidelobes around the main lobe.

Inspec keywords: radar; interference (signal)

Other keywords: interference problems; in-band interference; GWS function; nonradar services; telecommunication systems; in-band radars; transmitter; cardinal-series sampling expansion; transmission spectrum; telecommunication services; spectrally confined waveforms; US Navy radars; near-in time sidelobes; transmit-receive module; radar emissions; solid-state transmit modules

Subjects: Radar equipment, systems and applications