In this chapter we will introduce the concept of field coherence, which is necessary to describe ... more In this chapter we will introduce the concept of field coherence, which is necessary to describe fully the propagation of electromagnetic fields in both free space and nonvacuous channels. In particular, the ideas of temporal and spatial coherence will be presented together with the concept of the mutual coherence function. We will derive the equations which govern the propagation of both the field and the mutual coherence function in free space. In doing so, we will quantify the notions of monochromaticity and narrowbandedness. Finally, we will show how the presence of both nonvacuous channels and receiver optics affects the quantities defined above. Since the concepts discussed in this chapter do not relate strongly to problems in fiber transmission, those readers primarily interested in fibers can skip this chapter and proceed to Chapter 3. The concepts in this chapter lay the groundwork for subsequent introduction of generalized radiometry, which describes power flow for partially coherent fields. However, because of the specialized nature of this topic, it will be pursued in Appendix A.
A series of experiments were conducted to validate the performance of the free-space optical comm... more A series of experiments were conducted to validate the performance of the free-space optical communications (FSOC) subsystem under DARPA's FOENEX program. Over six days, bidirectional links at ranges.
Unattended Ground Sensor Technologies and Applications IV, 2002
The United States Army has embarked on a revolutionary transformation path towards a future, gene... more The United States Army has embarked on a revolutionary transformation path towards a future, general purpose Objective Force that is strategically responsive and dominant across the entire spectrum of military operations. Key to the success of the Objective Force will be the ability to generate unprecedented battlespace understanding and situational awareness. A layered surveillance approach, one that relies on a
ARPA surveillance technology for detection of targets hidden in foliage. [Proceedings of SPIE 209... more ARPA surveillance technology for detection of targets hidden in foliage. [Proceedings of SPIE 2093, 403 (1994)]. Lawrence E. Hoff, Larry B. Stotts. Abstract. The processing of large quantities of synthetic aperture radar data in real time is a complex problem. ...
In situ experimental data are presented on the off-axis radiance produced by a pulsed underwater ... more In situ experimental data are presented on the off-axis radiance produced by a pulsed underwater laser operating at a wavelength of 520 nanometers. Path lengths in homogeneous seawater range up to 50 meters with separations of up to more than 6 meters from the path. Absorption and scattering lengths in the water are about 6 and 4 meters, respectively. These results are compared with the predictions provided by popular models derived from radiative energy theory. Limitations are clearly shown on the accuracy of the radiance predicted by these models.
MODTRAN® has the option to employ one of several multiple-scattering algorithms while performing ... more MODTRAN® has the option to employ one of several multiple-scattering algorithms while performing MS calculations. Their particular use depends on the accuracy desired and the computation-time tolerance. The previous chapter provided some rules of thumb for MS considerations and selecting the appropriate algorithm. This chapter will discuss MODTRAN’s MS options, assumptions, and implications in more detail.
This article outlines how the Command Post of the Future (CPOF) program was successfully transiti... more This article outlines how the Command Post of the Future (CPOF) program was successfully transitioned from the Defense Advanced Research Projects Agency (DARPA) to the U.S. Army. Use of a tailored DoD 5000 acquisition strategy allowed the new CPOF technology to be fielded as a technology insertion into the Army Battle Command System (ABCS). Key to the success of this transition included the use of risk management techniques to drive the program forward, use of early and sustained feedback from the user community, maintaining transition funding stability, and honest and open communication between all stakeholders. The DoD 5000 acquisition strategy was tailored to fix the risks over time, rather than trying to develop the perfect product in one delivery.
: A comprehensive data base in blue-green propagation and devices developed at NOSC and elsewhere... more : A comprehensive data base in blue-green propagation and devices developed at NOSC and elsewhere was used to evaluate the feasibility of a space- based laser strategic satellite-to-submarine communication system designed to broadcast to operationally significant ocean areas of the world. Although a major capability in submarine communication can be obtained by sequentially transmitting data at a moderate rate to small spots that span the total operational area, this capability can be realized only by the correction of major deficiencies in the current blue-green technology base. Dramatically better optical filters and much more efficient and powerful lasers must be developed before the technical risk of the concept is reduced to a satisfactory level. Also required are the resolution of major uncertainties in the transmission of optical energy through clouds and a reduction in the uncertainties associated with present oceanic and cloud climatology data bases. The overall objective o...
Optical RF Communications Adjunct Program flight test results provide validation of the theoretic... more Optical RF Communications Adjunct Program flight test results provide validation of the theoretical models and hybrid optical radio frequency (RF) airborne system concepts developed by the Defense Advanced Research Projects Agency and the U.S. Air Force Research Laboratory. Theoretical models of the free-space optical communications (FSOC), RF, and network components accurately predict the flight test results under a wide range of day and night operating conditions. The FSOC system, including the adaptive optics and optical modem, can operate under high turbulence conditions. The RF and network mechanisms of Layer 2 retransmission and failover provide increased reliability, reducing end-to-end packet error rates. Overall the test results show that stable, long-range FSOC is possible and practical for near-term operations.
Abstract : This document discloses a pyroelectric camera for producing a continuous wide-band IR ... more Abstract : This document discloses a pyroelectric camera for producing a continuous wide-band IR display on a closed circuit television monitor. The apparatus comprises a Newtonian telescope focusing an image upon a pyroelectric vidicon via a motor driven mirror. The vidicon is sensitive only to changes in IR, the mirror is slowly wobbled so that the image moves across the face of the vidicon whose output is examined at intervals synchronized with the movement of the mirror. The picture produced by the synchronized vidicon output is a continuous, stationary display of the IR image. (Author)
Abstract : This report defines the figures-of-merit (FOMs) agreed upon by Task Group II of the Te... more Abstract : This report defines the figures-of-merit (FOMs) agreed upon by Task Group II of the Technical Coordination Program (TTCP) Joint Advisory Group (JAG) 12 data processing workshops held at NAVOCEANSYSCEN, San Diego on 25-30 March 1985. These FOMs can be applied to stationary, slow- and fast-moving target detection algorithm performance assessments. Keywords: HI-CAMP, TEAL RUBY, track correlation, track quality, threshold exceedances, IR imagery, pixel.
In this chapter we will introduce the concept of field coherence, which is necessary to describe ... more In this chapter we will introduce the concept of field coherence, which is necessary to describe fully the propagation of electromagnetic fields in both free space and nonvacuous channels. In particular, the ideas of temporal and spatial coherence will be presented together with the concept of the mutual coherence function. We will derive the equations which govern the propagation of both the field and the mutual coherence function in free space. In doing so, we will quantify the notions of monochromaticity and narrowbandedness. Finally, we will show how the presence of both nonvacuous channels and receiver optics affects the quantities defined above. Since the concepts discussed in this chapter do not relate strongly to problems in fiber transmission, those readers primarily interested in fibers can skip this chapter and proceed to Chapter 3. The concepts in this chapter lay the groundwork for subsequent introduction of generalized radiometry, which describes power flow for partially coherent fields. However, because of the specialized nature of this topic, it will be pursued in Appendix A.
A series of experiments were conducted to validate the performance of the free-space optical comm... more A series of experiments were conducted to validate the performance of the free-space optical communications (FSOC) subsystem under DARPA's FOENEX program. Over six days, bidirectional links at ranges.
Unattended Ground Sensor Technologies and Applications IV, 2002
The United States Army has embarked on a revolutionary transformation path towards a future, gene... more The United States Army has embarked on a revolutionary transformation path towards a future, general purpose Objective Force that is strategically responsive and dominant across the entire spectrum of military operations. Key to the success of the Objective Force will be the ability to generate unprecedented battlespace understanding and situational awareness. A layered surveillance approach, one that relies on a
ARPA surveillance technology for detection of targets hidden in foliage. [Proceedings of SPIE 209... more ARPA surveillance technology for detection of targets hidden in foliage. [Proceedings of SPIE 2093, 403 (1994)]. Lawrence E. Hoff, Larry B. Stotts. Abstract. The processing of large quantities of synthetic aperture radar data in real time is a complex problem. ...
In situ experimental data are presented on the off-axis radiance produced by a pulsed underwater ... more In situ experimental data are presented on the off-axis radiance produced by a pulsed underwater laser operating at a wavelength of 520 nanometers. Path lengths in homogeneous seawater range up to 50 meters with separations of up to more than 6 meters from the path. Absorption and scattering lengths in the water are about 6 and 4 meters, respectively. These results are compared with the predictions provided by popular models derived from radiative energy theory. Limitations are clearly shown on the accuracy of the radiance predicted by these models.
MODTRAN® has the option to employ one of several multiple-scattering algorithms while performing ... more MODTRAN® has the option to employ one of several multiple-scattering algorithms while performing MS calculations. Their particular use depends on the accuracy desired and the computation-time tolerance. The previous chapter provided some rules of thumb for MS considerations and selecting the appropriate algorithm. This chapter will discuss MODTRAN’s MS options, assumptions, and implications in more detail.
This article outlines how the Command Post of the Future (CPOF) program was successfully transiti... more This article outlines how the Command Post of the Future (CPOF) program was successfully transitioned from the Defense Advanced Research Projects Agency (DARPA) to the U.S. Army. Use of a tailored DoD 5000 acquisition strategy allowed the new CPOF technology to be fielded as a technology insertion into the Army Battle Command System (ABCS). Key to the success of this transition included the use of risk management techniques to drive the program forward, use of early and sustained feedback from the user community, maintaining transition funding stability, and honest and open communication between all stakeholders. The DoD 5000 acquisition strategy was tailored to fix the risks over time, rather than trying to develop the perfect product in one delivery.
: A comprehensive data base in blue-green propagation and devices developed at NOSC and elsewhere... more : A comprehensive data base in blue-green propagation and devices developed at NOSC and elsewhere was used to evaluate the feasibility of a space- based laser strategic satellite-to-submarine communication system designed to broadcast to operationally significant ocean areas of the world. Although a major capability in submarine communication can be obtained by sequentially transmitting data at a moderate rate to small spots that span the total operational area, this capability can be realized only by the correction of major deficiencies in the current blue-green technology base. Dramatically better optical filters and much more efficient and powerful lasers must be developed before the technical risk of the concept is reduced to a satisfactory level. Also required are the resolution of major uncertainties in the transmission of optical energy through clouds and a reduction in the uncertainties associated with present oceanic and cloud climatology data bases. The overall objective o...
Optical RF Communications Adjunct Program flight test results provide validation of the theoretic... more Optical RF Communications Adjunct Program flight test results provide validation of the theoretical models and hybrid optical radio frequency (RF) airborne system concepts developed by the Defense Advanced Research Projects Agency and the U.S. Air Force Research Laboratory. Theoretical models of the free-space optical communications (FSOC), RF, and network components accurately predict the flight test results under a wide range of day and night operating conditions. The FSOC system, including the adaptive optics and optical modem, can operate under high turbulence conditions. The RF and network mechanisms of Layer 2 retransmission and failover provide increased reliability, reducing end-to-end packet error rates. Overall the test results show that stable, long-range FSOC is possible and practical for near-term operations.
Abstract : This document discloses a pyroelectric camera for producing a continuous wide-band IR ... more Abstract : This document discloses a pyroelectric camera for producing a continuous wide-band IR display on a closed circuit television monitor. The apparatus comprises a Newtonian telescope focusing an image upon a pyroelectric vidicon via a motor driven mirror. The vidicon is sensitive only to changes in IR, the mirror is slowly wobbled so that the image moves across the face of the vidicon whose output is examined at intervals synchronized with the movement of the mirror. The picture produced by the synchronized vidicon output is a continuous, stationary display of the IR image. (Author)
Abstract : This report defines the figures-of-merit (FOMs) agreed upon by Task Group II of the Te... more Abstract : This report defines the figures-of-merit (FOMs) agreed upon by Task Group II of the Technical Coordination Program (TTCP) Joint Advisory Group (JAG) 12 data processing workshops held at NAVOCEANSYSCEN, San Diego on 25-30 March 1985. These FOMs can be applied to stationary, slow- and fast-moving target detection algorithm performance assessments. Keywords: HI-CAMP, TEAL RUBY, track correlation, track quality, threshold exceedances, IR imagery, pixel.
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Papers by Larry Stotts