Ilan Rusnak

Bio: Ilan Rusnak is an academic researcher from Rafael Advanced Defense Systems. The author has contributed to research in topics: Adaptive control & Missile. The author has an hindex of 19, co-authored 131 publications receiving 1319 citations. Previous affiliations of Ilan Rusnak include Drexel University & Technion – Israel Institute of Technology.

Cooperative Differential Games Strategies for Active Aircraft Protection from a Homing Missile

Abstract: Cooperative pursuit―evasion strategies are derived for a team composed of two agents. The specific problem of interest is that of protecting a target aircraft from a homing missile. The target aircraft performs evasive maneuvers and launches a defending missile to intercept the homing missile. The problem is analyzed using a linear quadratic differential game formulation for arbitrary-order linear players' dynamics in the continuous and discrete domains. Perfect information is assumed. The analytic continuous and numeric discrete solutions are presented for zero-lag adversaries' dynamics. The solution of the game provides 1) the optimal cooperative evasion strategy for the target aircraft, 2) the optimal cooperative pursuit strategy for the defending missile, and 3) the optimal strategy of the homing missile for pursuing the target aircraft and for evading the defender missile. The obtained guidance laws are dependent on the zero-effort miss distances of two pursuer―evader pairs: homing missile with target aircraft and defender missile with homing missile. Conditions for the existence of a saddle-point solution are derived and the navigation gains are analyzed for various limiting cases. Nonlinear two-dimensional simulation results are used to validate the theoretical analysis. The advantages of cooperation are shown. Compared with a conventional one-on-one guidance law, cooperation significantly reduces the maneuverability requirements from the defending missile.

Guidance of a homing missile via nonlinear geometric control methods

Abstract: This paper examines the guidance problem of an acceleration constrained homing missile when the initial missile heading is far from intercept course. A guidance strategy based on the theory of feedback linearization is presented, and simulation results are given comparing miss distance performance of the feedback linearized guidance law to proportional navigation. It is demonstrated that the feedback linearized guidance law is a viable option under these conditions. aT L*A(r) LgLkfh(x) N'

Optimal guidance for acceleration constrained missile and maneuvering target

Abstract: Explicit formulas of optimal guidance laws for an acceleration-constrained, arbitrary-order missile and maneuvering target are derived. These formulas are given in terms of the transfer function and acceleration constraint of the missile and the transfer function/shaping filter of the target. Optimal full-state feedback guidance law is synthesized against a target performing a barrel roll maneuver, and compared with the performance of proportional navigation (PN) for minimum and nonminimum phase missile. Simulation of a third-order missile shows the relative gain from using the full-order guidance law. >

Impact-time-control guidance law for anti-ship missiles

Abstract: In this paper, a new guidance problem with the impact time constraint is investigated, which can be applied to salvo attack of anti-ship missiles. The closed form solution based on the linear formulation is derived, suggesting an additional loop for adjusting the impact time in addition to the traditional optimal guidance loop. This solution is a combination of the well-known PNG law and the feedback of the impact time error, which is the difference between the impact time by PNG and the prescribed impact time. The new guidance law called ITCG (Impact-Time-Control Guidance) can be used to guide multiple missiles to hit a stationary target simultaneously at a desirable impact time. Nonlinear simulation of several engagement situations demonstrates the performance and feasibility of ITCG. In addition, the similarity of the closed form solution and APNG is investigated and the switching rule for practical implementation is discussed.

Optimal Guidance Laws with Terminal Impact Angle Constraint

Abstract: Optimal guidance laws providing the specified impact angle as well as zero terminal miss distance are generalized for arbitrary missile dynamics. The optimal guidance command is represented by a linear combination of the ramp and the step responses of the missile’s lateral acceleration. Optimal guidance laws in the form of the state feedback for the lag-free and the first-order lag system are derived, and their characteristics are investigated. Practical timeto-go calculation methods, which are important for the implementation of the optimal guidance laws, are proposed to consider the path curvature. Nonlinear and adjoint simulations are performed to investigate the performance of the proposed laws.

Clock jitter and quantizer metastability in continuous-time delta-sigma modulators

Abstract: The performance of continuous-time (CT) delta-sigma modulators (/spl Delta//spl Sigma/M's) suffers more severely from time jitter in the quantizer clock than discrete-time designs. Clock jitter adds a random phase modulation to the modulator feedback signal, which whitens the quantization noise in the band of interest and hence degrades converter resolution. Even with a perfectly uniform sampling clock, a similar whitening can be caused by metastability in the quantizer: a real quantizer has finite regeneration gain, and thus, quantizer inputs near zero take longer to resolve. This paper quantifies the performance lost due to clock jitter in a practical integrated CT /spl Delta//spl Sigma/M clocked with an on-chip voltage-controlled oscillator. It also characterizes metastability in a practical integrated quantizer using the quantizer output zero-crossing time and rise time as a function of both quantizer input voltage and the slope of the input voltage at the sampling instant, and predicts the maximum-achievable performance of a practical CT /spl Delta//spl Sigma/M given jitter and metastability constraints.