An Improved Phase-Derived Range Method Based on High-Order Multi-Frame Track-Before-Detect for Warhead Detection

It is crucial for a ballistic missile defense system to discriminate the true warhead from decoys. Although a decoy has a similar shape to the warhead, it is believed that the true warhead can be separated by its micro-Doppler features introduced by the precession and nutation. As is well known, the accuracy of the phase-derived range method, to extract micro-Doppler curves, can reach sub-wavelength. However, it suffers from an inefficiency of energy integration and high computational costs. In this paper, a novel phase-derived range method, using high-order multi-frame track-before-detect is proposed for micro-Doppler curve extraction under a low signal-to-noise ratio (SNR). First, the sinusoidal micro-Doppler range sequence is treated as the state, and the dynamic model is described as a Markov chain to obtain the envelopes and then the ambiguous phases. Instead of processing the whole frames, the proposed method only processes the latest frame at an arbitrary given time, which reduces the computational costs. Then, the correlation of all pairs of adjacent pulses is calculated along the slow time dimension to find the number of cells that the point scatterer crosses, which can be further used in phase unwrapping. Finally, the phase-derived range method is employed to get the micro-Doppler curves. Simulation results show that the proposed method is capable of extracting the micro-Doppler curves with sub-wavelength accuracy, even if SNR = −15 dB, with a lower computational cost.

Polish Public Opinion on the United States Missile Defense Complex in Poland

The ongoing cooperation between the United States and Poland on ballistic missile defense has been centered for a long time solely around the construction of the U.S. missile defense complex in Redzikowo, Poland. Although the complex is going to operate as an element of the NATO Integrated Air and Missile Defense System, its origins were tied to bilateral security and defense cooperation between the U.S. and Poland. As the presence of the U.S. military forces in Poland will remain crucial for Polish security and defense, and the societal support will be vital for its sustainment, it is worth exploring how Polish society reacted to concepts and plans for fielding the U.S. missile defense complex several years ago. The aim of this article was to explore the evolution of societal support and public opinion in Poland related to the construction of the U.S. missile defense complex in Redzikowo, Poland. The following research problem was posed: how has Polish public opinion about the missile defense complex construction changed over time? The research relied on methods of qualitative and quantitative analysis, and the primary research technique was the analysis of public opinion polls in Poland between 2004 and 2019. Public opinion has remained interested in the developments related to hosting the U.S. missile defense complex in Poland since early negotiations to the project implementation phase. The project was seen in a broader context of security and defense cooperation with the U.S. and within the NATO.

Threat Asymmetry and Transition in Deterrence: Technical Assessment of India’s Ballistic Missile Defense Shield

The global change in perception following the Cold War from deterrence by punishment in the form of Mutually Assured Destruction (MAD) to deterrence by denial has multiplied the utility of the Ballistic Missile Defense (BMD). India’s willingness to acquire and develop the advanced BMD shield is inspired, especially by Reagan’s Star Wars and the global shift in using it as an instrument of deterrence by denial. But as the application of its offensive-defensive paradox, India is raising a multi-layer air defense system to enhance its freedom of action and to acquire impunity in carrying out what New Delhi believes as its ‘limited war’ strategy against Pakistan. However, despite having a number of air defense systems in place including the recently acquired advanced S-400 air defense system, India is unable to shield itself completely from the counter-force or counter-value strikes by Pakistan as evident by the Balakot debacle. This is not only because India lags behind in BMD technology but also because of its inability to afford a comprehensive pan-national BMD shield. Therefore, the paper argues that, India’s attempt to build a multi-layer air defense system, rather than ensuring balance of power, destabilizes it and the delicate deterrence in place. This is because the threat asymmetry allows Pakistan to develop advanced nuclear capabilities including BMD evading delivery vehicles like MIRV as the offensive firepower to communicate the threat as an effective deterrence. Resultantly, the employment of BMD in South Asia disturbs strategic parity, fractures deterrence, drags down nuclear threshold and hence raises the cost of conflict between Pakistan and India with an elevated threat of annihilation.