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Normalized analysis of interceptor missiles using the four-state optimal guidance system

November 1, 2003
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Journal Article
Author:
Joel Alpert
Published in:
J. Guid. Control Dyn., Vol. 26, No. 6, November-December 2003, p. 838-845.
Topic:
missile defense
R&D area:
R&D group:

Summary

Performance prediction of miss distance due to sensor measurement errors and random target manuevers for missiles using proportional navigation guidance has been analyzed using the adjoint technique; a normalization technique has been usedto reduce the solution of the set of differential equations describing the proportional navigationguidance problemto a set of algebraic equations using normalized steady-state adjointmiss distance coefficients. The four-state optimalguidance system is generally accepted to yield superior miss distance performance to that of proportional navigation guidance. The previously mentioned normalization technique is described and extended to the four-state optimal guidance system to calculate a new set of values for the normalized steady-state adjointmiss distance coef. cients for this con. guration. Plots of these normalized coefficients as a function of a normalized tuning parameter provide designers with insight into system performance sensitivities to design parameter and intercept parameter variations. The advantage of this technique is that the results are closed-form equations, and the analyst neither needs to perform simulations nor even to solve the adjoint differential equations. In addition, optimalguidance system results formiss distance due to target spiral maneuver are presented asmiss distance normalized to the target maneuver spiral radius, thus providing valuable insights into interceptor performance.
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Summary

Performance prediction of miss distance due to sensor measurement errors and random target manuevers for missiles using proportional navigation guidance has been analyzed using the adjoint technique; a normalization technique has been usedto reduce the solution of the set of differential equations describing the proportional navigationguidance problemto a set of...

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Normalized analysis of interceptor missiles using the four-state optimal guidance system

A constrained joint optimization approach to dynamic sensor configuration

November 3, 2002
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Conference Paper
Author:
Dana Sinno
…
Published in:
36th Asilomar Conf. on Signals, Systems, and Computers, Vol. 2, 3-6 November 2002, pp. 1179-1183.
Topic:
sensors
R&D area:
R&D group:

Summary

Through intelligent integration of sensing and processing functions, the sensing technology of the future is evolving towards networks of configurable sensors acting in concert. Realizing the potential of collaborative real-time configurable sensor systems presents a number of challenges including the need to address a number of challenges including the need to address the massive global optimization problem resulting from incorporating a large array of control parameters. This paper proposes a systematic approach to addressing complex global optimization problems by constraining the problem to a set of key control parameters and recasting a mission-oriented goal into a tractable joint optimization formula. Using idealized but realistic physical models, a systematic methodology to approach complex multi-dimensional joint optimization problems is used to compute system performance bounds for dynamic sensor configurations.
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Summary

Through intelligent integration of sensing and processing functions, the sensing technology of the future is evolving towards networks of configurable sensors acting in concert. Realizing the potential of collaborative real-time configurable sensor systems presents a number of challenges including the need to address a number of challenges including the need...

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A constrained joint optimization approach to dynamic sensor configuration

Improving the high altitude performance of tail-controlled endoatmospheric missiles

August 5, 2002
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Journal Article
Author:
Paul Zarchan
…
Published in:
AIAA Guidance, Navigation, and Control Conf., 5-8 August 2002.
Topic:
missile defense
R&D area:
R&D group:

Summary

It is demonstrated that at high altitude the performance of a tail-controlled aerodynamic missile can degrade because of the existence of low frequency right-half plane zeroes in the airframe transfer function when either proportional navigation or optimal guidance is used. A new guidance law that accounts for the airframe zeroes is developed numerically and shown to have superior performance to existing guidance laws at the higher altitudes. Although no closed-form solution for the guidance law is presented, the resultant numerical values for the control gains of the guidance law can easily be stored as a multidimensional table in existing on-board flight control computers. Two methodologies for computing the guidance law control gains are presented.
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Summary

It is demonstrated that at high altitude the performance of a tail-controlled aerodynamic missile can degrade because of the existence of low frequency right-half plane zeroes in the airframe transfer function when either proportional navigation or optimal guidance is used. A new guidance law that accounts for the airframe zeroes...

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Improving the high altitude performance of tail-controlled endoatmospheric missiles

Time domain processing of frequency domain GPR signatures for buried land mine detection

April 1, 2002
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Conference Paper
Author:
Audrey J. Dumanian
…
Published in:
SPIE, Vol. 4742, Part One, Detection and Remediation Technologies for Mines and Minelike Targets VII, 1-5 April 2002, pp. 339-348.
Topic:
detection systems
R&D area:
R&D group:

Summary

This paper investigates the feasibility of detecting plastic antipersonnel land mines buried in lossy, dispersive, rough soils using a stepped-frequency ultra wideband (WB) ground-penetrating radar (GPR). Realistic land mine scenarios were modeled using a two-dimensional (2D) finite difference firequency domain (FDFD) technique. Assuming normal incidence plane wave excitation, the scattered fields were generated over a large frequency bandwidth (.5 to 5 GHz) for a variety of mine-like shapes, different soil types, and multiple receiver locations. The simulation results showed that for a ground penetration sensor located just above the soil surface, the strong reflection signals received from the rough ground surface obscured the buried target's fiquency response signal. The simulated GPR WB frequency response data at each receiver location was transformed to the time domain using the fast fourier transform. Time domain processing permits high resolution measurement of target features that are invariant to the ground roughness and also that are dependent on the soil characteristics as well as the burial depth and size of the mine, Specifically, two or more characteristic timing peaks are observed in the simulation results suggesting that the ultra-wideband spectral radar response may yield particular advantages not exploited by currently employed detection systems. It is also shown that by using time-gating to remove the strong ground reflection signals, the target signals are selectively enhanced (as expected), but more surprisingly, the target frequency response signature is almost completely recovered.
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Summary

This paper investigates the feasibility of detecting plastic antipersonnel land mines buried in lossy, dispersive, rough soils using a stepped-frequency ultra wideband (WB) ground-penetrating radar (GPR). Realistic land mine scenarios were modeled using a two-dimensional (2D) finite difference firequency domain (FDFD) technique. Assuming normal incidence plane wave excitation, the scattered...

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Time domain processing of frequency domain GPR signatures for buried land mine detection

Circuit-fed tile-approach configuration for millimeter-wave spatial power combining

January 1, 2002
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Journal Article
Author:
Mark A. Gouker
…
Published in:
IEEE Trans. Microw. Theory Tech., Vol. 50, No. 1, Part 1, January 2002, pp. 17-21.
Topic:
antennas
R&D area:
R&D group:

Summary

In this paper, a circuit-fed spatially combined transmitter array is described for operation at 44 GHz. The array contains 256 elements where each element consists of a monolithic-microwave integrated-circuit amplifier and a circularly polarized microchip patch antenna. The array is constructed using 16-element tile-approach subarrays. Each subarray is a two RF-level (three-dimensional) multichip module containing integrated microstrip patch antennas. The basic construction of the transmitter array resembles tile-approach phased arrays; however, the implementation has been tailored for the power-combining application. The peak performance at 43.5 GHz is equivalent isotropic radiated power of 40.6 dBW (11570 W), effective transmitted power (Peff) of 5.9 W, dc-to-RF efficiency of 7.3%, and system gain of 35 dB.
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Summary

In this paper, a circuit-fed spatially combined transmitter array is described for operation at 44 GHz. The array contains 256 elements where each element consists of a monolithic-microwave integrated-circuit amplifier and a circularly polarized microchip patch antenna. The array is constructed using 16-element tile-approach subarrays. Each subarray is a two...

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Circuit-fed tile-approach configuration for millimeter-wave spatial power combining

Comparison of two flat reflector-type designs for dual-polarization, dual-band operation

July 8, 2001
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Conference Paper
Author:
Sean M. Duffy
…
Published in:
IEEE Antennas and Propagation Society Int. Synp. 2001 Digest, Vol. 2, 8-13 July 2001, pp. 288-291.
Topic:
antennas
R&D area:
R&D group:

Summary

The parabolic reflector remains an essential antenna for high-gain applications. This is a result of its desirable characteristics based on geometric optics. These include relative frequency independence for sufficiently large apertures and high aperture efficiency. However, the parabolic reflector occupies a large volume. This may be aesthetically unappealing on the sides of buildings and structures. Also, from a mobile user perspective, a desirable characteristic is having a large aperture during operation while having a small volume when packed away and not in use. The parabolic reflector is typically constructed of multiple petals for mobile uses, but it does not pack into as small a volume as a flat, thin antenna would due to the curvature of the paraboloid. Therefore, the primary goal of the antennas studied in this work is developing flat reflector antennas to utilize the advantages of large reflector apertures while remaining capable of packing into a small volume. In addition, system requiremenls dictated dual-band, dual-polarized operation. Two flat reflectors are compared: a reflectarray and a zoned reflector. While each design is inherently narrow-band, methods of achieving dual-band operation were employed.
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Summary

The parabolic reflector remains an essential antenna for high-gain applications. This is a result of its desirable characteristics based on geometric optics. These include relative frequency independence for sufficiently large apertures and high aperture efficiency. However, the parabolic reflector occupies a large volume. This may be aesthetically unappealing on the...

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Comparison of two flat reflector-type designs for dual-polarization, dual-band operation

Accurate modeling of dual dipole and slot elements used with photomixers for coherent terahertz output power

June 1, 2001
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Journal Article
Author:
Sean M. Duffy
…
Published in:
IEEE Trans. Microw. Theory Tech., Vol. 49, No. 6, June 2001, pp. 1032-8.
Topic:
antennas
R&D area:
R&D group:

Summary

Accurate circuit models derived from electromagnetic simulations have been used to fabricate photomixer sources with optimized high-impedance antennas. Output powers on the order of 1 uW were measured for various designs spanning 0.6-2.7 THz. The improvement in output power ranged from 3 to 10 dB over more conventionally designed photomixers using broad-band log-spiral antennas. Measured data on single dipoles, twin dipoles, and twin slots are in good agreement with the characteristics predicted by the design simulations.
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Summary

Accurate circuit models derived from electromagnetic simulations have been used to fabricate photomixer sources with optimized high-impedance antennas. Output powers on the order of 1 uW were measured for various designs spanning 0.6-2.7 THz. The improvement in output power ranged from 3 to 10 dB over more conventionally designed photomixers...

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Accurate modeling of dual dipole and slot elements used with photomixers for coherent terahertz output power

MEMS microswitches for reconfigurable microwave circuitry

March 1, 2001
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Journal Article
Author:
Sean M. Duffy
…
Published in:
IEEE Microw. Wirel. Compon. Lett., Vol. 11, No. 3, March 2001, pp. 106-108.
Topic:
antennas
R&D area:
R&D group:

Summary

The performance is reported for a new microelectromechanical structure (MEMS) cantilever microswitch. We report on both dc- and capacitively-contacted microswitches. The dc-contacted microswitches have contact resistance of less than 1 ohm, and the RF loss of the switch up to 40 GHz in the closed position is 0.1-0.2 dB. Capacitively-contacted switches have an impedance ratio of 141:1 from the open to closed state and in the closed position have a series capacitance of 1.2 pF. The capacitively-contacted switches have been measured up to 40 GHz with S(21) less than -0.7 dB across the 5-40 GHz band.
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Summary

The performance is reported for a new microelectromechanical structure (MEMS) cantilever microswitch. We report on both dc- and capacitively-contacted microswitches. The dc-contacted microswitches have contact resistance of less than 1 ohm, and the RF loss of the switch up to 40 GHz in the closed position is 0.1-0.2 dB. Capacitively-contacted...

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MEMS microswitches for reconfigurable microwave circuitry

Combining-efficiency X-band spatial power-combined array using a multilayered packaging architecture

October 1, 2000
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Journal Article
Author:
Sean M. Duffy
…
Published in:
IEEE Trans. Microw. Theory Tech., Vol. 48, No. 10, October 2000, pp. 1769-1771.
Topic:
antennas
R&D area:
R&D group:

Summary

The design of a high combining-efficiency spatial power-combined array is described in this paper. A multilayered stacked stripline architecture enables a compact stable design. An array incorporating antenna active impedance and proper amplifier matching is measured with a combining efficiency of 87%, radiating 6.8 W of an available 7.8 W into the ideal uniformly illuminated array directivity at 10.1 GHz.
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Summary

The design of a high combining-efficiency spatial power-combined array is described in this paper. A multilayered stacked stripline architecture enables a compact stable design. An array incorporating antenna active impedance and proper amplifier matching is measured with a combining efficiency of 87%, radiating 6.8 W of an available 7.8 W...

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Combining-efficiency X-band spatial power-combined array using a multilayered packaging architecture

MEMs microswitch arrays for reconfigurable distributed microwave components

July 16, 2000
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Conference Paper
Author:
Carl O. Bozler
…
Published in:
IEEE Antennas and Propagation Society Int. Symp. Digest, Vol. 2, 16-21 July 2000, pp. 587-591.
Topic:
antennas
R&D area:
R&D group:

Summary

A revolutionary device technology and circuit concept is introduced for a new class of reconfigurable microwave circuits and antennas. The underlying mechanism is a compact MEMs cantilever microswitch that is arrayed in two-dimensions. The switches have the ability to be individually actuated. By constructing distributed circuit components from an array, the individual addressability of the microswitch provides the means to reconfigure the circuit trace and, thus, provides the ability to either fine-tune or completely reconfigure the circuit element's behavior. Device performance can be reconfigured over a decade in bandwidth in the nominal frequency range of 1 to 100 GHz. In addition, other circuit-element attributes can be reconfigured such as instantaneous bandwidth, impedance, and polarization (for antennas). This will enable the development of next-generation communication, radar and surveillance systems with agiIity to reconfigure operation for diverse operating bands, modes, power levels, and waveforms.
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Summary

A revolutionary device technology and circuit concept is introduced for a new class of reconfigurable microwave circuits and antennas. The underlying mechanism is a compact MEMs cantilever microswitch that is arrayed in two-dimensions. The switches have the ability to be individually actuated. By constructing distributed circuit components from an array...

READ MORE
MEMs microswitch arrays for reconfigurable distributed microwave components
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