0018-9251 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TAES.2018.2801443, IEEE Transactions on Aerospace and Electronic Systems Combating Radar Pulse Jamming using Clipping Based Non-coherent Pulse Integration Furqan Abbasi*, Usman Iqbal** and Sohail Ahmed*** Air University, Islamabad, Pakistan. Tel: ***+92-323-5024468. Emails: *150073@students.au.edu.pk, **150072@students.au.edu.pk, ***sohailahmed71@hotmail.com, ***sohail.ahmed@mail.au.edu.pk Abstract— A novel pulse integration has been put forward in which the radar receiver, before combin- ing envelope detector outputs in all pulses, first clips them to a suitable level to suppress excessive energy inflicted by a jammer. Mathematical expressions for various decision metrics relevant to this scheme are derived. Using these metrics it is shown that the proposed scheme, when combined with frequency agility, yields healthy performance gain over simi- lar detection schemes when operating against pulse jamming. Index Terms— Radar detection; pulse integration; jamming; radar countermeasures; electronic protec- tion I. INTRODUCTION Pulse jamming can inflict a great deal of deterioration of the radar detection by trans- mitting pulses in the same frequencies as that used by the radar thus creating false alarms. The jammer might even have information about the radar signal’s key parameters such as pulse width and repetition interval, by virtue of which it can conjure false targets. Random pulses from a jammer or accidental source can sim- ilarly mar the radar detection. A number of approaches to suppress pulse interference have been analyzed in [1]–[3]. Numerous modern signal processing techniques as well as con- ventional anti-jamming techniques such as fre- quency hopping or agility [4] and Constant False Alarm Rate (CFAR) techniques [2], [3], [5]–[8] are useful Electronic Counter Counter Measures (ECCM). In this contribution, we propose a funda- mentally different approach and investigate the inherent diversity offered by a frequency agile radar in combination with pulse integration to combat pulse jamming. Pulse integration [4] is aimed at combining target returns in multiple pulses in one scan so as to boost the signal-to- noise ratio (SNR), which results in improved detection. Thanks to frequency agility, the sig- nals in various pulses may be independent or uncorrelated; this is especially true if transmis- sion frequency is changed with every pulse. Therefore, pulse integration also offers time and frequency diversity, which can be useful in countering the effects of partial band jam- ming, i.e. when some frequencies used by a frequency agile radar may be jammed while others remain jamming-free. Noting similarities between non-coherent detection in radar and wireless communication receivers [9], [10], in previous contributions [11], [12], we proposed two novel pulse integration techniques that were shown to possess remarkable robustness against noise jamming when used in a fre- quency agile radar. In this contribution, we propose another novel non-coherent technique of pulse integration which suppresses pulse jamming by clipping envelope detector output in each range bin to an appropriate value in order to combat the jamming effect, before envelope detector outputs are summed as done in conventional non-coherent pulse integration (NCPI). This scheme also takes its cue from a wireless communication anti-jamming tech-