This PDF file contains the front matter associated with SPIE Proceedings Volume 11422, including the Title Page, Copyright information, and Table of Contents.

Progress with Interferometric Fiber Optic Gyroscopes Interferometric fiber optic gyroscopes (IFOGs) have been in production for many years and for a given size, weight and power it has demonstrated higher performance than other sensors technologies. This is due to the use of relatively long fiber optic coils with small diameter, providing high performance and small size. Several IFOG developers, including Honeywell, are using new error-reduction techniques and improved component technologies to advance the technology. A review of the reported performance advancements will be presented, as well as a discussion of IFOG long life reliability. This is a proven technology for strategic grade gyros and has demonstrated the ability to meet strategic grade performance without compromising bandwidth or requiring boutique manufacturing processes.

A time delay integration imaging system using a commercial-off-the-shelf (COTS) interline transfer-charge-coupled device (IT-CCD) was developed. The developed system was applied to the remote sensing sensor onboard the Super Low Altitude Test Satellite (SLATS), “TSUBAME”, one of satellite missions from the Japan Aerospace Exploration Agency. The sensor has demonstrated high-resolution of the satellite images even with a low cost of development. The system must suit a remote sensing sensors onboard small satellites, which are expected to be in higher demand in the near future. In the present paper, principles and features of the developed system are introduced, as well as expected applications.

We report on the calibration of the Compact Midwave Imaging Sensor (CMIS) which has been developed by The Johns Hopkins University - Applied Physics Lab (JHU/APL) under a grant from the NASA Earth Science Technology Office (ESTO). At the heart of the CMIS instrument is a newly-developed high operating temperature (HOT) detector made from III-V compounds in a Type II Superlattice design. The instrument is sensitive to 3 particular bands in the IR spectrum which have been noted for their usefulness in determining cloud coverage and temperatures. The bands used were centered at 2.25 μm, 3.75 μm and 4.05 μm. The focal plane array (FPA) was based on the FLIR ISC0405 640×512 pixel readout integrated circuit with 15 μm square pixels. The CMIS design included a 5 zone “butcher block” filter placed in close proximity to the FPA and refractive optical elements contained inside the barrel of the cold shield such that the optics were cooled to approximately the same temperature as the FPA. A small-size, low-power closed-cycle cooler was used to maintain the FPA and the optics at a temperature of 150 K, at which the dark current was low enough to allow integration times longer than 50 ms for cold background scenes. JHU/APL developed the camera control electronics (CCE) and data processing unit (DPU) for running the FPA, performing image processing functions on the data and storing it in memory. The CCE and DPU were designed for possible use on an orbital payload but for the airborne flight the commercial versions of some of the parts specified for spaceflight were used. This paper will describe the laboratory calibration procedures and results.

NASA Goddard Space Flight Center (GSFC) has successfully developed and tested a custom-designed low-noise multi-channel digitizer (MCD) application specific integrated circuit (ASIC) for operation in harsh radiation environments. The MCD-ASIC is optimized for low-frequency and low-voltage signal measurements from sensors and transducers. It has 20 input channels where each channel is comprised of auto-zeroed chopper variable-gain amplifier, post amplifier, and a second order ΣΔ modulator. ΣΔ analog-to-digital converter (ADC) relies on oversampling and noise shaping to achieve high-resolution conversion. However, the MCD-ASIC requires digital filtering and decimation to convert the output single bit streams from the ADC to useful data words. A parallel digital platform such as a field-programmable-gate-array (FPGA) is highly suitable to fully leverage the capabilities of the MCD-ASIC. The FPGA controls the MCD-ASIC via serial peripheral interface (SPI) protocol and acquires data from it. A Python-script communicates with the FPGA board through a USB interface on a cross operating platform. Using this architecture, the system is capable of monitoring up to 20 voltage readout channels simultaneously in a real-time manner. Each channel’s parameters can be programmed independently allowing maximum user versatility. In this paper, we present analysis of the analog front-end, the implementation of the digital processing unit on the FPGA, and provide noise performance results from the MCD-ASIC readout.

Free space optical (FSO) communication systems can be used to transmit data at a high data rate while being immune to noise that typical communication systems are susceptible to. Current radio frequency (RF) trans- mission systems are flooding the usable spectrum, causing it to become overcrowded and inconvenient to use. This results in more noise and potentially a lower bandwidth based on the part of the spectrum a given RF system is able to operate in. The free space optical transceiver (FSO-TRx) system proposed in this paper helps solve these issues with a modular and scalable design.

When applying the Disruption Tolerant Networking (DTN) technique to satellite communications (SATCOM) with significant long delays, two problems result. First, to enhance the communication efficiency, Performance Enhancing Proxies (PEPs) used in satellite communications need to be integrated with DTN around SATCOM links, and the interoperability between DTN and PEP should be developed. Second, all data moving from a red core (secure intranet) to a black core (unsecured public network) should be encrypted using High Assurance Internet Protocol Encryption (HAIPE) devices. To solve the encryption problem, a TCP over TCP solution was proposed, which encodes original TCP flow information from HAIPE, and then reconstructs new TCP streams and encapsulates HAIPE-encrypted original TCP packets in them. These new TCP streams can be natively handled by PEPs and thus the full TCP performance can be achieved. However, the TCP over TCP solution requires special mechanisms to deal with the interaction between the congestion control of the inner and outer TCP links. To achieve congestion goals, this paper develops a throughput system model, and provides an analysis of the impacts of TCP retransmission. Our analysis shows a throughput reduction when both inner and outer TCP react to packet loss. Possible solutions are also proposed using delay shaping to remove the congestion control of the TCP tunnel. An analysis is provided to explain the mechanisms behind our solutions, and experiment results are also provided to support our design.

Satellite Communication (SATCOM) systems are playing a more and more important role in both civilian and tactical scenarios with large deployment and user groups currently. However, long propagation delay and high packet loss rate of the SATCOM in higher earth orbits satellites degrades the communication performance severely. Existing works, such as Performance Enhancing Proxy (PEP), have addressed this performance issue via splitting the end-to-end TCP connection into several sub-connections, so that the low performance SATCOM communication link will no longer affect the entire TCP connection performance from the sender to the receiver. Nevertheless, PEP's functionalities can be disabled once the data encryption like High Assurance Internet Proto- col Encryption (HAIPE) was introduced due to the security requirement of the communication over SATCOM. Therefore, we targeted on the solution of using transportation layer tunneling, i.e., TCP and UDP tunnel, in this paper to explore the opportunity of re-enabling the PEP functionalities at the presence of data encryption and further enhancing the performance of the end-to-end TCP communication. We also designed and implemented a Mininet based emulation testbed to conduct all experiments and evaluations for better understanding on the effectiveness of the tunnel solution with different configurations (e.g., TCP congestion control mechanism). Based on the evaluation results presented in the paper, we successfully further improved the end-to-end TCP communication performance with TCP/UDP tunnel while maintaining the functionalities of the performance enhancement solution like PEP. Moreover, we provided detailed analysis on the advantages and disadvantages of using different tunnels with different configurations as well as our recommendations for performance enhancement in such SATCOM communication environment.

With the ever-growing number of resident space objects (RSOs) surrounding the Earth, it is imperative that we develop techniques for determining their current and future state by leveraging a collection of radio frequency and optical observations to maintain space domain awareness (SDA). The state of an RSO at a future time is determined by its current state and the forces acting upon it. In theory, this prediction is trivial; however, knowing all of the forces is not practical. When a space object undergoes a maneuver, this simple extrapolation fails, and more measurements are required before an updated state estimate would be available causing tracking methods to fail. One means by which an RSO undergoes a maneuver, is by firing its thruster which provides a transient component to its signature. For example, many small satellites use Hall effect thrusters to perform station keeping. The emission from these thrusters can be up to three times greater than the rest of the satellite. This change in the signature provides information about the aspect of the RSO and the amount of energy expended by the engine to produce a thrust on the object. This information can be passed back to the state estimators to reduce the time necessary to update the RSO’s state. In this paper, we present a model for estimating the upper bound of the signature change of an RSO due to thruster engagement. We then present our initial results of a rendered model both with and without a plume present.

Remote sensing techniques offer the only viable opportunity to learn more about the estimated thousands of small pieces of debris that orbit the Earth near the GEO belt. In previous work, multispectral optical and infrared sensing techniques have been employed to characterize debris and the population of small GEO belt debris. This paper examines an infrared remote sensing model for GEO belt debris and the uncertainty in the remote sensing techniques, with the aim of suggesting a way to improve upon previous attempts to characterize the population of GEO belt debris by either reducing uncertainty or improving radiometric sensitivity. Analytical methods applied to measurements of GEO belt debris data, in addition to detailed modeling of notional sensors in infrared wavebands are presented.

Remote detection of spacecraft arcing is important for the satellite operators in order to properly respond for anomalies caused by spacecraft charging due to the space weather conditions. Satellites operating at geosynchronous orbit (GEO) are prone to spacecraft charging due to fluxes of high energy electrons onto and beneath their surfaces, usually coincident with geomagnetic storms. Thus, satellite surfaces can charge thousands of volts with respect to each other whereas entire satellites can charge tens of thousands of volts negative of their surrounding space plasma. The ensuing electric fields can cause local discharges (arcs), endangering the normal operation of the satellite. It has been shown that the most probable cause of the excess power loss of the global positioning system (GPS) satellites is radiationinduced arcing observed on the solar arrays coverglass and producing its contamination. In this paper, we used a new 327 MHz feed system installed on the Arecibo 305 m radio telescope for the remote arc detection of two low-inclination GEO satellites, namely, SES-10 and AMC- 3, and compare it to the standard 327 MHz feed system observations of the high-inclination GEO satellite ASTRA 1-D. Statistical analysis of arcing data revealed a high arcing rate for both SES-10 and AMC-3, but SES-10 arcs less often than AMC-3. On the other hand, ASTRA 1-D observations show no significant evidence that scans of the satellite within view of the telescope (“on-source”) are any different than those with the satellite outside of it (“off-source”), suggesting no-arcing behavior of this satellite. It is believed that the design of the ASTRA 1-D satellite’s solar arrays precludes arcing.

The United States Space Surveillance Network catalogs around 23,000 Resident Space Objects (RSOs). The completeness of their coverage of the true RSO population decreases gradually with object size and radar reflectivity. While the population of cm level space debris is poorly represented in the catalogs these space bullets can cause severe damage to satellites and spacecrafts in addition to being likely much more numerous than larger pieces. This research project focuses on the ability to peek into this debris population using space-based high sensitivity, fast frame rate, wide field visible imaging from low Earth orbit. The simulator developed focuses on a LEO to LEO (sensor to RSO) scenario and the capacity to constrain their orbit trajectory. In the Matlab simulator, a simple specular/diffuse sphere model is used for the debris in order to generate the object’s apparent magnitude for any sun-debris-observer arrangement. Satellite and debris relative velocities and orbits are also considered in order to determine the length of the streak left by the debris on any given exposure sequence and the number of photons per pixel. The exact timing, position, length and orientation of the streak contains information constraining the object’s orbit. The generation of representative star backgrounds matched to the sensor high sensitivity is also an important part of the simulator since it affects the effective limiting sensitivity to faint transiting source. This simulator allows us to trade various sensor parameters in order to optimize the camera design. The conclusion from this work contribute to the global effort in Space Situational Awareness (SSA) by assessing the impact of including space based optical imagery in the detection mix.

Space superiority includes space protection and space situational awareness (SSA), which require rapid and accurate space object behavioral motion and operational intent discovery. The presence of clutter in addition to real-time and hidden information constraints greatly complicates the space awareness decision-making to control both ground-based and spacebased surveillance assets. To increase SSA, generative adversarial networks (GANs) are realizable for rapid discovery of evasive satellite behaviors. Although GANs have shown good results in synthesizing real-world images, GANs “remain remarkably difficult to train” and “approaches to attacking this problem still rely on heuristics that are extremely sensitive to modifications”. This paper describes a modification to a game-theoretic approach to incorporate GANs and train the networks using a general sum game theory. The enhanced GAN model for satellite behavior discovery is called Space unveiled Behavior GAN (SuB-GAN) in this paper. The structure includes training the GANs as a repeated game using a Fictious play concept framework, within which the discriminator (resp. generator) is updated according to the best response to the mixture outputs from a sequence of previously trained. In particular, the discriminator outputs converge to the optimum discriminator function and the mixed output from the sequence of trained generators converges to the data distribution. The simulated training datasets are used to demonstrate the enhanced GANs in the SSA domain. The performance the SuB-GAN is compared with the convolutional neural network (CNN) models showing promising results.

As space technologies mature, the cost of inserting materiel into orbit continues to decrease. Advances in the miniaturization of hardware and decreasing launch costs have resulted in space becoming increasingly accessible to nations and organizations. This is especially the case with the low Earth orbit, which is used as a staging environment for satellite constellations that provide imaging, communications, and other services. While very large satellite constellations were previously fielded by only a handful of nations, with increasing ease of access to space, many more space-faring organizations are designing systems of hundreds or thousands of satellites. This has led to the emergence of a new problem: how to manage satellite inventories in an optimal manner. To address this challenge, we propose the use of Markov decision process (MDP) models to compute the optimal fielding policy for satellites within a constellation, given the current state. We apply this model to the Global Positioning System (GPS), a system which requires a minimum of 24 satellites to provide system-level operations, but which consists of approximately 30 satellites in medium Earth orbit. Our analysis, performed entirely independently from the GPS sustainment rationale, suggests that the mathematically optimal steady-state inventory level for the GPS constellation is 31 satellites, which provides affirmation for both the GPS sustainment policy and our proposed model. In addition, we perform sensitivity analysis on various parameters such as the risk aversion of the decision makers and ordering limits of additional satellites.

In this paper, multi-player sequential game with an unknown non-stationary irrational player is investigated for cooperative autonomous robots decision-making applications. In practice, the irrationality of agents can seriously degrade the effectiveness of decision making especially for distributed cooperative tasks with applications to multi-robot systems. Specifically, The irrationality can be caused by the cooperation agent's mechanical failure or sensor flaw. To handle this issue, a novel dynamic evaluation system, which includes two important parameters, i.e. cooperation index and competitive flag, is designed to efficiently quantify the player's level of cooperation or competition firstly. Then, the continuous deep Q network space is proposed to predict the action value with respect to a continuous cooperation index.

Image sensors have been explored heavily in automotive applications for collision avoidance and varying levels of autonomy. It requires a degree of brightness, therefore, the use of an image sensor in nighttime operation or dark conditions can be problematic along with challenging weather such as fog. Radar sensors have been employed to help cover the various environmental challenges with visible spectrum cameras. Edge computing technology has the potential to address a number of issues such as real-time processing requirements, off-loading of processing from congested servers, and size, weight, power, and cost (SWaP-C) constraints. This paper proposes a novel Hybrid Object DEtection and Tracking (HODET) using mmWave Radar and Visual Sensors at the edge. The HODET is a computing application of low SWaP-C electronics performing object detection, tracking and identification algorithms with the simultaneous use of image and radar sensors. While the machine vision camera alone could estimate the distance of an object, the radar sensor will provide an accurate distance and vector of movement. This additional data accuracy can be leveraged to further discriminate a detected object to protect against spoofing attacks. A real-world smart community public safety monitoring scenario is selected to verify the effectiveness of HODET, which detects, tracks objects of interests and identify suspicious activities. The experimental results demonstrate the feasibility of the approach.

Advancement in artificial intelligence (AI) and machine learning (ML), dynamic data driven application systems (DDDAS), and hierarchical cloud-fog-edge computing paradigm provide opportunities for enhancing multi-domain systems performance. As one example that represents multi-domain scenario, a “fly-by-feel” system utilizes DDDAS framework to support autonomous operations and improve maneuverability, safety and fuel efficiency. The DDDAS “fly-by-feel" avionics system can enhance multi-domain coordination to support domain specific operations. However, conventional enabling technologies rely on a centralized manner for data aggregation, sharing and security policy enforcement, and it incurs critical issues related to bottleneck of performance, data provenance and consistency. Inspired by the containerized microservices and blockchain technology, this paper introduces BLEM, a hybrid BLockchain-Enabled secure Microservices fabric to support decentralized, secure and efficient data fusion

One of the major restrictions on the practical applications of unmanned aerial vehicles (UAV) is their incomplete self-sufficiency, which makes continuous operations infeasible without human oversights. The more oversight UAVs require, the less likely they are going to be commercially advantageous when compared to their alternatives. As an autonomous system, how much human interaction is needed to function is one of the best indicators evaluating the limitations and inefficiencies of the UAVs. Popular UAV related research areas, such as path planning and computer vision, have enabled substantial advances in the ability of drones to act on their own. This research is dedicated to in-flight operations, in which there is not much reported effort to tackle the problem from the aspect of the supportive infrastructure. In this paper, an Autonomous Service network infrastructure (AutoServe) is proposed. Aiming at increasing the future autonomy of UAVs, the AutoServe system includes a service-oriented landing platform and a customized communication protocol. This supportive AutoServe infrastructure will autonomize many tasks currently done manually by human operators, such as battery replacement. A proof-of-concept prototype has been built and the simulation experimental study validated the design.

This paper provides an overview of Aerospace R&D work on digital engineering consistent with the U.S. Department of Defense (DOD) Digital Engineering Strategy encouraging innovation in rapid development of space systems. An objective of this investigation was to identify challenges associated with DE and to formulate an approach to mitigate the challenges. One key challenge within a larger enterprise is the fact that models will be developed by different developers/modelers, using different ontologies, different tools, and different levels of detail. Our approach introduced innovative techniques for connecting disparate DE models, defining/controlling system interfaces and defining/managing interface baseline specifications within a DE construct. The approach includes a proposed flexible, robust, and agile platform and associated implementation framework of processes, tools, digital models, digital threads and digital use cases. The approach is being submitted for U.S. patent application and was applied on a pilot project involving a spacecraft Bus, mission payload (P/L), and digitized PL-to-Bus interface.

This paper provides (i) an overview of a proposed Systems-of-Systems Enterprise Architecture (SOSEA) CONOPS (Concept of Operations) framework and associated resiliency models, (ii) a summary of the work done by CSUF Graduate Student Team (GST) on the implementation of the framework and advanced mathematical modeling effort for Matlab modeling of the resiliency models, and (iii) preliminary simulations results obtained by CSUF-GST for notional SATOPS and SATCOM SOSEA CONOPS use cases. The key achievements of the CSUF-GST include SOSEA databases for civilian, commercial, and military space and ground systems, orbital dynamics models for simulating SOSEA space systems and ground networks, simplified dynamic communication link margin and availability, and Matlab models for Resilience Assessment Index (RAI), Spectrum Resiliency Assessment Index (SRAI) and Resilient Capacity models against intentional and un-intentional Radio Frequency Interference (RFI) sources.

The paper presents a multiple-criteria decision model based on the concept of pairwise outranking and its use in enterprise architecture assessment. More specifically, the paper applies the Marquis de Condorcet principle found in the ELECTRE models to demonstrate that under highly complex decision situations when existing optimization techniques might not yield optimal outcome, a systematic outranking approach can lead to a satisfactory and safe decision. This paper presents a mathematical version of ELECTRE II (sorting by elimination) implemented in Matlab with visual interpretation. The model was successfully tested on an ex-post notional use case involving four enterprise architecture alternatives based on five evaluation criteria: market uncertainty, technological uncertainty, technical and performance risk, cost and schedule risks, and payoffs and costs.

Methods are proposed for hardening a missile warning satellite against jamming and damage from unlimited running time 1-MW airborne, 1-MJ ground-based, and space-based lasers. The unhardened telescope design is based on a model of a missile warning satellite telescope developed by the American Physical Society Study Group on Boost-Phase Intercept Systems for National Missile Defense. The APS telescope can step-stare or linearly scan. In response to an attack, laser warning devices can close a shutter at the first focal surface. Filter wheels in a collimated section of the optical path, insert filters to protect focal plane arrays and readout ICs from jamming and damage. Neutral density filters are inserted to assess threats. The shutter is reopened. The reduced laser intensity in the collimated section protects the filters. The field of view (FOV) is reduced with a field stop wheel, with differently sized apertures, to allow the system to step-stare between multiple jammers in the normal FOV. A cryogenic gas cools fore-optics heated by lasers or by X-rays from nuclear bursts.