Raghav Harini Venkatesan

Bio: Raghav Harini Venkatesan is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Guidance system & Air-to-air missile. The author has an hindex of 2, co-authored 4 publications receiving 39 citations.

A New Guidance Law for the Defense Missile of Nonmaneuverable Aircraft

Abstract: In this brief, a new guidance law for the defense missile of nonmaneuverable aircraft is formulated based on dynamic game considerations. First, a simple differential game of protecting a static target in 2-D, involving simple motions for the attacker and defender, is introduced. The analysis is then extended to a moving noncooperative target in 2-D, in view of the fact that a nonmaneuverable aircraft would not be able to cooperate with the defender. A heuristic solution for the game is proposed and tested, and the results of the 2-D analysis are then extended to 3-D to formulate a new guidance law for the defense missile called the command to optimal interception point (COIP) guidance law. The validity of the new guidance law is checked using trajectory and envelope simulations, built with high-fidelity 6-DOF models using the computer-aided design of aerospace concepts in C++ framework. Performance comparisons are shown between the COIP guidance law and the recently proposed airborne command to line-of-sight (A-CLOS) guidance law. The results show that the performances of COIP and A-CLOS guidance laws are almost identical in a coplanar engagement scenario, but the COIP law has the additional advantage of working with only position information, without the knowledge of motion of the players. In addition, in a noncoplanar engagement case studied, the defense missile is shown to achieve intercept using the COIP guidance law, but fails when using the A-CLOS guidance law.

Key factors that affect the performance of flares against a heat-seeking air-to-air missile

Abstract: Deploying flare decoys against heat-seeking threats involves various parameters such as flare timing, flare ejection velocity, direction of ejection and the number of flares used. In this study, an...

An improved command to optimal interception point guidance law for real-time applications

Abstract: In this paper, two alternate ways of implementing the recently proposed Command to Optimal Interception Point (COIP) guidance law, formulated based on the target guarding dynamic game problem, are proposed. The alternate implementations have significantly reduced computational times and are therefore more suited for real-time applications like robotics. Firstly, the earlier proposed implementation of the COIP guidance law is introduced and factors which affect its computation time are analyzed. Based on them, an alternate expression for the guidance law is derived, and two ways of implementing the derived alternate expression are discussed. Finally, the performance of these various implementations are compared. Averaged over 100 computational experiments, the two alternate implementations of the COIP guidance law were found to be almost 2 times and 7 times faster than the original implementation.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Design and Analysis of State-Feedback Optimal Strategies for the Differential Game of Active Defense

Abstract: This paper is concerned with a scenario of active target defense modeled as a zero-sum differential game. The differential game theory as developed by Isaacs provides the correct framework for the analysis of pursuit-evasion conflicts and the design of optimal strategies for the players involved in the game. This paper considers an Attacker missile pursuing a Target aircraft protected by a Defender missile which aims at intercepting the Attacker before the latter reaches the Target aircraft. A differential game is formulated where the two opposing players/teams try to minimize/maximize the distance between the Target and the Attacker at the time of interception of the Attacker by the Defender and such time indicates the termination of the game. The Attacker aims to minimize the terminal distance between itself and the Target at the moment of its interception by the Defender. The opposing player/team consists of two cooperating agents: The Target and the Defender. These two agents cooperate in order to accomplish the two objectives: Guarantee interception of the Attacker by the Defender and maximize the terminal Target-Attacker separation. In this paper, we provide a complete, closed form solution of the active target defense differential game; we synthesize closed-loop state feedback optimal strategies for the agents and obtain the Value function of the game. We characterize the Target's escape set and show that the Value function is continuous and continuously differentiable over the Target's escape set, and that it satisfies the Hamilton–Jacobi–Isaacs equation everywhere in this set.

Cooperative Missile Guidance for Active Defense of Air Vehicles

Abstract: In air combat, an active countermeasure against an attacking missile homing into a Target aircraft entails the launch of a defending missile. The Target is protected by the Defender, which aims to intercept the Attacker before the latter reaches the Target aircraft. A differential game is presented where the Target–Defender team strives to maximize the terminal separation between the Target and the Attacker at the time instant where the Attacker is intercepted by the Defender, whereas the Attacker strives to minimize the said separation. This paper discusses the case where the Defender is endowed with a positive capture radius. Optimal strategies for the three agents are derived and simulation examples illustrate the effectiveness of the proposed approach.

Multiple Pursuer Multiple Evader Differential Games

Abstract: In this article an $N$ -pursuer versus $M$ -evader team conflict is studied. This article extends classical differential game theory to simultaneously address weapon assignments and multiplayer pursuit-evasion scenarios. Saddle-point strategies that provide guaranteed performance for each team regardless of the actual strategies implemented by the opponent are devised. The players’ optimal strategies require the codesign of cooperative optimal assignments and optimal guidance laws. A representative measure of performance is employed and the Value function of the attendant game is obtained. It is shown that the Value function is continuously differentiable and that it satisfies the Hamilton–Jacobi–Isaacs equation—the curse of dimensionality is overcome and the optimal strategies are obtained. The cases of $N=M$ and $N>M$ are considered. In the latter case, cooperative guidance strategies are also developed in order for the pursuers to exploit their numerical advantage. This article provides a foundation to formally analyze complex and high-dimensional conflicts between teams of $N$ pursuers and $M$ evaders by means of differential game theory.

An integrated guidance and control approach in three-dimensional space for hypersonic missile constrained by impact angles

Abstract: A new robust three-dimensional integrated guidance and control (3D-IGC) approach is investigated for sliding-to-turn (STT) hypersonic missile, which encounters high uncertainties and strict impact angle constraints First, a nonlinear state-space model with more generality is established facing to the design of 3D-IGC law With regard to the as-built nonlinear system, a robust dynamic inversion control (RDIC) approach is proposed to overcome the robustness deficiency of traditional DIC, and then it is applied to construct the basic 3D-IGC law combining with backstepping method In order to avoid the problems of "explosion of terms" and high-frequency chattering, an improved 3D-IGC law is further proposed by introducing dynamic surface control and continuous approximation approaches From the computer simulation on a hypersonic missile, the proposed 3D-IGC law not only guarantees the stable flight, but also presents the precise control on terminal locations and impact angles Moreover, it possesses smooth control output and strong robustness