Proceedings of MILCOM '93 - IEEE Military Communications Conference最新文献

{"title":"A featureless wideband Gaussian noise signaling modem employing acoustic charge transport (ACT) technology","authors":"A. Vigil, C. Ricci, R. Martin, R.J. Kansy","doi":"10.1109/MILCOM.1993.408603","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408603","url":null,"abstract":"Low probability of intercept communication schemes are crucial in scenarios where transmitter covertness must be maintained. Popular efforts to improve covertness are known to employ or enhance featureless qualities of wideband spread spectrum waveforms. The authors implement the strategy of modulating an already featureless wideband waveform - average white Gaussian noise - such that the modulation waveform remains featureless while transmitting binary data. The technique employed is adapted directly from the theoretical description given by Cooper at MILCOM '82. A working hardware model for a featureless wideband Gaussian noise signaling binary data modem has been prepared using standard ACT programmable transversal filters (PTFs). A transmitted reference modulation scheme is employed which enables decoding at the receiver without phase locked carrier recovery or code synchronization. ACT PTFs are used at the receiver to recorrelate the reference signal with the modulated signal. Correlation sequences are fully programmable.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129862294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of commercial wireless LAN technology to forward area mobile communications","authors":"M. Epstein, Paul A. Gilmour, C. Yoon","doi":"10.1109/MILCOM.1993.408619","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408619","url":null,"abstract":"Two applications have been identified for wireless local area network (LAN) technology in the forward area of the battlefield: a soldier radio and distributed command posts. The Army's soldier radio/soldier computer initiative is characterized by low to medium data rate requirements (10 kbps or higher), optimization for low cost and light weight, and fully-mobile operation. It utilizes the UHF or low SHF bands, and has a range to 2 km. The distributed command posts application is characterized by high data rate requirements (1 to 10 Mbps), optimization for low probability of intercept (LPI) or detection (LPD), and quasi-mobile operation (rapid setup after a move). It utilizes the EHF band, and has a range to 10 km. The authors survey requirements and architectural alternatives for both applications. The issues which make current commercial off-the-shelf (COTS) technology unsuitable for a tactical environment are examined, and modifications which may be made to COTS equipment to deal with these issues are proposed. These issues include operation on the move, high-loss propagation path, frequency band, security requirements, and interference rejection. Technologies which are common to the two applications are identified. Current COTS technology appears to be a good match to the soldier radio application. Suggestions are made for how COTS technology may be applied to the distributed command post application.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127007097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terminal system and capability for ARPA-NASA high-speed SONET/ATM experiments over NASA's Advanced Communications Technology Satellite","authors":"M. Bergamo, Principal Investigator","doi":"10.1109/MILCOM.1993.408514","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408514","url":null,"abstract":"Gigabit Earth Stations (GESs) are under development for the ARPA-NASA Gigabit Satellite Network using NASA's Advanced Communications Technology Satellite (ACTS). The GESs will be equipped with SONET OC-3/3c (155.54 Mb/s) and SONET OC-12/12c (622.08 Mb/s) user interfaces. Through these interfaces SONET/ATM experimenters will be able to establish long-haul point-to-point and point-to-multipoint full-duplex OC-3/12 links via satellite. These links will have bit error rate performance comparable to fiber (BER <10/sup -11/) using relatively small 3.4-meter diameter antennas. Satellite channel sharing and synchronization with the ACTS on-board microwave switch matrix (MSM) and beam matching capabilities will be performed using satellite-switched time division multiple access (SS-TDMA) techniques, to be the implemented within the GES's \"Digital Terminal\" subsystem. The Gigabit Earth Stations are being designed to perform the function of conventional SONET multiplexers and to be capable of integration with any standard SONET terrestrial network. As SONET multiplexers in the SONET hierarchy, the GESs will perform clock synchronization between geographically-separated end-user interfaces by terminating the section and line overheads of the SONET frames at the transmitting end of each satellite link, by transporting the payloads plus payload-pointer-bytes over the satellite, and by regenerating the SONET frames and corresponding section and the line overheads at the receiving ends of the satellite links. The Gigabit Satellite Network will have provisions for remote monitoring and control, and statistics collection for SONET/ATM experimenter support. In order to make the system available to a variety of experimenters and to be able to reach points where terrestrial fiber may not be available, the Gigabit Earth Stations will be provided in transportable weather-protected configurations.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116338920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New approaches to DoD information-systems acquisition","authors":"Commander Michael, Loescher","doi":"10.1109/MILCOM.1993.408584","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408584","url":null,"abstract":"There are really three defense issues arising from the global information revolution, all inextricably related, like three movements within a single Sonata. The first centers on the changing nature and doctrine of modern warfare resulting from the proliferation of new information technologies. The second addresses the kind of infrastructure DoD needs to conduct warfare in the information age. The third issue keys on three new principles that together create a model for how DoD might more efficiently acquire information-systems technology.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114731330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A low profile vehicle mobile SATCOM antenna","authors":"A. C. Smith","doi":"10.1109/MILCOM.1993.408578","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408578","url":null,"abstract":"A steerable low profile microwave antenna for satellite communication from a moving vehicle is described. It is based on a Luneburg lens and reflector combination which is steerable in both azimuth and elevation. Beam steering is achieved through the use of a novel epicyclic gearbox which is controlled by attitude and heading sensors within the vehicle.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126561703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An approximate maximum likelihood algorithm for direction finding with diversely polarized arrays","authors":"R. Keizer, T. Bronez, J. Creekmore","doi":"10.1109/MILCOM.1993.408492","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408492","url":null,"abstract":"Improved direction-finding (DF) performance may be realized by employing a diversely polarized antenna array. However, maximum likelihood (ML) DF algorithms for such an array have greater computational complexity than those for a uniformly polarized array with the same number of antenna elements. In particular, the dimension of the nonlinear search embedded in ML estimation of azimuth and elevation is twice as large with a diversely polarized array as with a uniformly polarized array. While ML is a practical and powerful technique for small search dimensions, it rapidly becomes intractable as the dimension increases. The authors propose a new approximate maximul likelihood (AML) algorithm for reduced-complexity direction finding with diversely polarized arrays. The AML algorithm eliminates the polarization dimensions by incorporating a suboptimal but effective polarization estimate into the exact likelihood function. Optimization of the resulting approximate likelihood function requires half the search dimension of the exact likelihood function. To assess the performance of the AML algorithm, the authors develop an approach for measuring the sensitivity of the estimator to errors in the sensor covariance matrix; these errors may result from model mismatch, finite integration time, or other factors. The approach is applicable to a large class of parameter estimators that maximize a differentiable objective function of the parameters and the data. The authors derive numerically a sensitivity matrix that maps perturbations of the covariance matrix onto perturbations of the estimated directions. They analyze the sensitivity matrix to compare the performance of Schmidt's MUSIC method, the exact ML method, and the AML method for a simulated scenario with two sources of arbitrary correlation and polarization. The results show that the proposed AML algorithm typically performs as well as ML and, that both ML and AML often perform much better than MUSIC. The AML algorithm is an attractive alternative to ML, obtaining comparable DF performance from a diversely polarized array with reduced computational complexity.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128164478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antenna arrays for CDMA systems with multipath","authors":"B. Khalaj, A. Paulraj, T. Kailath","doi":"10.1109/MILCOM.1993.408593","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408593","url":null,"abstract":"A major advantage of spread-spectrum communication systems is their ability to exploit the multipath structure of the received signal. Different paths can be characterized by their time delays, attenuations, and angles of arrival. A standard RAKE receiver estimates the path delays and attenuations and coherently combines different path signals to mitigate the effects of multipath. A method of exploiting the spatial properties of the multipath environment using multiple element antenna arrays is proposed. Both array vectors and time structure of the multipath channel are estimated using the special code structure of CDMA systems.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132468616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of Rician fading and partial-band interference on noise-normalized, fast frequency-hopped MFSK receivers","authors":"M. Kragh, R. Robertson","doi":"10.1109/MILCOM.1993.408524","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408524","url":null,"abstract":"The performance of an M-ary orthogonal frequency-shift keying (MFSK) communication system using fast frequency-hopped spread spectrum waveforms transmitted over a frequency-nonselective, slowly fading channel with partial-band interference is analyzed. A procedure referred to as noise-normalization combining is used by the system receiver to minimize partial-band interference effects. Each hop is assumed to fade independently. The partial-band interference is modeled as a Gaussian process. Both the signal and the partial-band interference are assumed to be affected by the fading channel which is modeled as Rician. The effect of fading of the partial-band interference on worst-case receiver performance is relatively minor. When there is no signal fading or when the signal facing is Rician, the counter-intuitive result of poorer receiver performance when the partial-band interference experiences fading is obtained. This effect is most pronounced when the signal does not fade and the partial-band interference experiences Rayleigh fading.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134381782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A satellite-based position location system for global data collection and messaging","authors":"J. Murphy, S. Morgan","doi":"10.1109/MILCOM.1993.408642","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408642","url":null,"abstract":"A recent reduction in defense expenditures has prompted a renewed interest in using commercial, off-the-shelf technology for military applications. The authors introduce two such systems. The ARGOS system, in use since 1978, relays geo-location and low rate, one-way telemetry data back to several collection centers. This system primarily supports several environmental applications which are deployed on maritime, terrestrial and airborne platforms. A new generation system, called STARSYS, being readied for operation in the mid-1990s, will be capable of supporting millions of users with low cost geo-location and two-way data communications. In addition, a precursor to STARSYS called the STARSYS Early-Entry Program, which provides potential users with an opportunity to develop and refine system requirements, will be discussed together with the system performance characteristics of both systems.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131568344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance of DS/CDMA communications with continuous-phase signals","authors":"M. Landolsi, Wayne E. Stark","doi":"10.1109/MILCOM.1993.408719","DOIUrl":"https://doi.org/10.1109/MILCOM.1993.408719","url":null,"abstract":"Two examples of Direct-Sequence Code Division Multiple Access (DS/CDMA) communication systems with offset quadrature signals and smoother chip pulses than the rectangular pulse of the conventional Offset Quadrature Phase Shift Keying (OQPSK) modulation are presented. The two systems use Minimum Shift Keying (MSK) and Sinusoidal Frequency Shift Keying (SFSK), which are continuous-phase modulation formats. It is shown that these two systems outperform OQPSK with regard to both bandwidth consumption and bit error probability.<<ETX>>","PeriodicalId":323612,"journal":{"name":"Proceedings of MILCOM '93 - IEEE Military Communications Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131886064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}