While radar systems have always employed diverse waveforms, waveform diversity, as coined in 2002... more While radar systems have always employed diverse waveforms, waveform diversity, as coined in 2002, touches on a variety of radar topics including both established and emerging technologies. Over time, a number of waveform diversity applications have matured to the point where they have become practical and implementable. Nevertheless, there remain significant challenges to full implementation of many applications of unique interest. This paper provides an overview of some practical waveform diversity applications and discusses challenges that are yet to be overcome.
Conference on Information Sciences and Systems, 2007
Constant envelope orthogonal frequency-division multiplexing (CE-OFDM) is evaluated as a potentia... more Constant envelope orthogonal frequency-division multiplexing (CE-OFDM) is evaluated as a potential wideband radar pulse compression modulation using ambiguity function analysis.
Modern radar systems often have the conflicting requirements of a large phased array antenna for ... more Modern radar systems often have the conflicting requirements of a large phased array antenna for increased power-aperture product and/or angular resolution versus wide instantaneous signal bandwidth for fine range resolution. Pulse-to-pulse diversity may also be desired as a countermeasure against coherent repeater jammers. Using the multicarrier nature of orthogonal frequency-division multiplexing to encode wide instantaneous bandwidth pulses we propose a novel digital phased array architecture which mitigates dispersion effects experienced when the array main beam is electronically steered off broadside. The result is the ability to transmit and receive wideband pseudo-random phase coded pulses with a phased array antenna. Simulation results are used to quantify the benefit of the architecture. An overview of digital orthogonal frequency-division multiplexing waveform generation is also provided.
International Waveform Diversity and Design Conference, 2009
This paper offers a tutorial treatment of constant envelope OFDM, covering power efficiency and s... more This paper offers a tutorial treatment of constant envelope OFDM, covering power efficiency and spectral efficiency tradeoffs and discusses recent advancements in applying CE-OFDM to radar. A dual-use architecture is proposed offering both radar and communications capabilities on a common platform.
Improvements in RF and digital technology have made digital array radar (DAR) feasible. The combi... more Improvements in RF and digital technology have made digital array radar (DAR) feasible. The combination of orthogonal frequency-division multiplexing (OFDM) as a wideband pulse compression modulation with a DAR architecture allows time dispersion effects to be mitigated for electrically-long antenna arrays. This concept can be extended to the simultaneous operation of multiple radar modes. Each mode is allocated some number of OFDM subcarriers. The subcarriers corresponding to a particular mode are then phase-shifted to create an element-to-element phase shift across the antenna array to steer the full-aperture antenna beam for that particular mode. This concept multiplexes the modes in the frequency domain while the OFDM-based DAR allows each mode to experience the full-aperture gain on transmit and receive while being electronically steered to an independent spatial position.
AbstractCoherent multiple-input multiple-output (MIMO) radar is characterized by having a transm... more AbstractCoherent multiple-input multiple-output (MIMO) radar is characterized by having a transmit antenna array and a receive antenna array located in a pseudo-monostatic configuration such that desired target returns from the far-field are coherent. Each element ...
While radar systems have always employed diverse waveforms, waveform diversity, as coined in 2002... more While radar systems have always employed diverse waveforms, waveform diversity, as coined in 2002, touches on a variety of radar topics including both established and emerging technologies. Over time, a number of waveform diversity applications have matured to the point where they have become practical and implementable. Nevertheless, there remain significant challenges to full implementation of many applications of unique interest. This paper provides an overview of some practical waveform diversity applications and discusses challenges that are yet to be overcome.
Conference on Information Sciences and Systems, 2007
Constant envelope orthogonal frequency-division multiplexing (CE-OFDM) is evaluated as a potentia... more Constant envelope orthogonal frequency-division multiplexing (CE-OFDM) is evaluated as a potential wideband radar pulse compression modulation using ambiguity function analysis.
Modern radar systems often have the conflicting requirements of a large phased array antenna for ... more Modern radar systems often have the conflicting requirements of a large phased array antenna for increased power-aperture product and/or angular resolution versus wide instantaneous signal bandwidth for fine range resolution. Pulse-to-pulse diversity may also be desired as a countermeasure against coherent repeater jammers. Using the multicarrier nature of orthogonal frequency-division multiplexing to encode wide instantaneous bandwidth pulses we propose a novel digital phased array architecture which mitigates dispersion effects experienced when the array main beam is electronically steered off broadside. The result is the ability to transmit and receive wideband pseudo-random phase coded pulses with a phased array antenna. Simulation results are used to quantify the benefit of the architecture. An overview of digital orthogonal frequency-division multiplexing waveform generation is also provided.
International Waveform Diversity and Design Conference, 2009
This paper offers a tutorial treatment of constant envelope OFDM, covering power efficiency and s... more This paper offers a tutorial treatment of constant envelope OFDM, covering power efficiency and spectral efficiency tradeoffs and discusses recent advancements in applying CE-OFDM to radar. A dual-use architecture is proposed offering both radar and communications capabilities on a common platform.
Improvements in RF and digital technology have made digital array radar (DAR) feasible. The combi... more Improvements in RF and digital technology have made digital array radar (DAR) feasible. The combination of orthogonal frequency-division multiplexing (OFDM) as a wideband pulse compression modulation with a DAR architecture allows time dispersion effects to be mitigated for electrically-long antenna arrays. This concept can be extended to the simultaneous operation of multiple radar modes. Each mode is allocated some number of OFDM subcarriers. The subcarriers corresponding to a particular mode are then phase-shifted to create an element-to-element phase shift across the antenna array to steer the full-aperture antenna beam for that particular mode. This concept multiplexes the modes in the frequency domain while the OFDM-based DAR allows each mode to experience the full-aperture gain on transmit and receive while being electronically steered to an independent spatial position.
AbstractCoherent multiple-input multiple-output (MIMO) radar is characterized by having a transm... more AbstractCoherent multiple-input multiple-output (MIMO) radar is characterized by having a transmit antenna array and a receive antenna array located in a pseudo-monostatic configuration such that desired target returns from the far-field are coherent. Each element ...
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Papers by John Stralka