Advantages of Adaptive Nulling in GPS Guided Munitions

Richard Arseneau

Abstract:	GPS receivers are essential in the guidance system of present and future smart munitions. With military dependence on GPS guided munitions, the need for anti- jamming techniques in hostile environments increases. An “L” band adaptive canceler can be implemented to decrease a munition’s susceptibility to jamming . American Nucleonics Corporation (ANC) and Interstate Electronics Corporation (IEC) collaborated in the testing of an Ll adaptive canceler. The canceler was designed by ANC and integrated with an IEC GPS receiver. The origins of adaptive interference cancellation extend back nearly four decades [ 11. Commercial applications of this technology during the past thirty years include adaptive equalization for modems [2], electrocardiography [3], acoustic noise cancellation [4], and echo cancellation on telephone lines [5]. In general, the received signal consists of a desired signal accompanied by an (undesired) interfering signal while a separate but correlated version of the interfering signal, often called a reference signal, is also available [ 11. The adaptive processor, however configured, produces an output signal that resembles the interfering signal. This signal is subtracted from the received signal to eliminate, at least partially, the undesired signal while leaving the desired signal unaltered. Depending upon the selected adaptive processor configuration, significant (possibly perfect) cancellation of the interfering signal may be obtained. Many configurations (filter structure, type of processing, adaptive algorithm, etc.) for adaptive cancelers are feasible [6]. The adaptive nuller described herein uses analog processing, a recursive filter structure and a least mean squares (LMS) algorithm.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	797 - 802
Cite this article:	Arseneau, Richard, "Advantages of Adaptive Nulling in GPS Guided Munitions," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 797-802.
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