Bicameral LLC v. NXP USA, Inc. et al

Western District of Texas, txwd-6:2018-cv-00294

Exhibit Ex. 538EX3

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2 Exhibit 538EX3 2 SAE TECHNICAL PAPER SERIES 1999-01-2335 An On-Line Lightning Monitoring System for Spacecraft Launch Support Paolo G. Sechi and Richard C. Adamo SRI International Jason C. Chai The Aerospace Corp. Reprinted From: Proceedings of the 1999 International Conference on Lightning and Static Electricity (ICOLSE) (P–344) International Conference on Lightning and Static Electricity Toulouse, France June 22-24, 1999 400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 The appearance of this ISSN code at the bottom of this page indicates SAE's consent that copies of the 2 paper may be made for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc. Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sec- tions 107 or 108 of the U.S. Copyright Law. 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Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is published in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USA 2 1999-01-2335 An On-Line Lightning Monitoring System for Spacecraft Launch Support Paolo G. Sechi and Richard C. Adamo SRI International Jason C. Chai The Aerospace Corp. Copyright © 1999 Society of Automotive Engineers, Inc. ABSTRACT INTRODUCTION This paper provides a technical overview of the on-line The OLMS has been developed to provide real-time lightning monitoring system (OLMS), a sophisticated sec- monitoring of the effects of lightning-induced EM tran- ond-generation system designed to monitor the effects of sients on ground-based space systems. Existing launch lightning-induced electromagnetic (EM) transients on procedures often require that, in the event of nearby or ground-based space systems. The potential damage of direct lightning strikes, launch operations be suspended sensitive electronic systems by lightning-induced EM and system level tests be performed to confirm that dam- transients is of concern to system designers, operators, age or upset to payload or launch vehicle systems has and maintainers. The OLMS uses broadband sensors to not occurred. Such retest operations are costly and, as measure free-field radiation (electric and magnetic experience has shown, often unnecessary. fields), as well as energy coupled to conductors (current It would, however, be imprudent to proceed with launch and voltage). Characterization of the measured signals is activities under these circumstances unless accurate and performed by two subsystems in parallel: an analog tran- timely data regarding the characteristics and severity of sient processor (TPM) and conventional state-of-the-art actual EM transients induced by a particular lightning digitizers. While the digitizers are able to provide the event were available. actual high-frequency waveforms desired by many users, they have inherent limitations in duty cycle and large data The OLMS is designed to provide such data and thus storage requirements. The companion TPM electronics reduce or eliminate the costs and risks to launch vehicle processes the data in real time to extract parameters of and payload operations related to the EM effects of local interest, such as peak amplitudes and energy, all in the lightning activity on launch base operations. analog domain and with full signal bandwidth. Unlike digi- tizer-based systems, the TPM is guaranteed never to OVERVIEW miss a transient event and produces a very compact result data stream. The data from the OLMS are available The major OLMS components include (1) EM sensors in real time and are accessed by users via the Internet, installed at appropriate locations at the launch pad, (2) a using a standard web browser interface. The OLMS sys- sensor station at the base of each pad to collect sensor tem is being developed to support spacecraft launches at data, and (3) a master station at a remote location for a number of launch sites in the United States. The OLMS data processing and distribution to networked users. Fig- will allow users to monitor accurately the EM threat to ure 1 illustrates the system architecture and interconnec- their sensitive electronic systems and retest systems only tions and is discussed in detail in the following sections. if necessary. This is of value since overtesting not only leads to very expensive delays but also affects sched- ELECTROMAGNETIC SENSORS – The OLMS uses ules, while undertesting may result in the deployment of a broadband field sensors to measure free-field radiation, damaged system where repair may not be possible. and current and voltage sensors to measure energy cou- pled to conductors. A typical baseline installation con- tains up to 16 sensors, including 1 2 • Electric field sensors designed to measure the ambi- TRANSIENT PULSE MONITOR – The TPM is a unique ent field normal to the sensor in the frequency range component of the OLMS. The TPM continuously ana- from 10 kHz to 250 MHz and amplitudes up to lyzes sensor inputs in real time and provides a summary 300 kV/m. of important transient characteristics; it has an analog • Magnetic field sensors that measure the rate of bandwidth greater than 250 MHz and an amplitude change of the magnetic field (dB/dt, or B-dot) at fre- dynamic range greater than 60 dB. quencies up to 250 MHz and maximum rates of The TPM electronics continuously monitors the sensor change up to 107 Tesla/s. inputs with zero "dead time" and guarantees that critical • Clamp-on current sensors that operate from 10 kHz events are never missed. The TPM electronics character- to 100 MHz and measure currents up to 5 kA. izes the input transient in terms of several important • Differential voltage sensors that operate from DC to parameters. These parameters include positive and neg- 100 MHz and measure voltages up to 1300 V. ative peak amplitudes, total energy in the waveform, and peak power in five frequency bands. The concept of parameterization of transients (also called "norms") was The electric and magnetic field sensors are typically developed for the field of EMP (electromagnetic pulse) mounted in pairs on a stainless steel plate attached to research and has found application in characterizing a the umbilical tower (UT). A typical installation might broad spectrum of EM environments, including lightning include a pair of sensors at the top of the UT as a refer- electromagnetic pulse (LEMP), high-power microwaves ence measurement of the impinging external radiated (HPM), and electromagnetic interference/compatibility field. A pair of sensors on the UT at payload level pro- (EMI/EMC) [1]. These applications have in common the vides a measurement of the fields near the payload. quantification of broadband transient data, specifically Where an electromagnetically shielded payload enclo- with concern for how these transients might damage or sure exists, a pair of sensors is also located inside this upset electronic systems. enclosure to provide a direct measurement of the field inside the enclosure. Over the past decade, we have successfully applied the concept of parameterization of transients for use in light- Current sensors are typically installed around critical ning monitoring, where many issues similar to those umbilical cables to monitor the currents within. Similarly, involved in making EMP measurements arise. Specifi- differential voltage sensors may be attached to measure cally, straightforward digitization of the waveform results potential differences generated between conductors. The in huge volumes of data that must be stored and subse- sensors are all devices with a 50 Ω output impedance; quently processed and analyzed. In practice, it is the thus, any new or potentially better-suited sensor with a 50 analyzed data that are valuable, not the digitized wave- Ω output could be used with the system. The sensor sig- forms. It has been shown that only three or four parame- nal outputs are routed to the sensor station, using semi- ters are sufficient to characterize most transients for most rigid coaxial cables permanently installed in protected interference control purposes [2]. These parameters are cable raceways. also the basis for United States Military Standard proce- dures for performing EMP testing [3]. The analog TPM SENSOR STATION – The sensor station, contained in a electronics computes these parameters directly and in rack-mounted, electromagnetically shielded enclosure, real time, reducing the data stream by six orders of mag- employs two complementary technologies for the simul- nitude or more. taneous monitoring of signals from up to sixteen electro- magnetic sensors: Parameters such as peak amplitude and total energy are particularly interesting because damage mechanisms for • State-of-the-art waveform digitizers electronics are predominantly of two types: (1) overvolt- • Analog TPM (transient pulse monitor) electronics age or overcurrent, and (2) overenergy [4]. Overvoltage or overcurrent causes a breakdown of a material that The TPM electronics and waveform digitizers operate in either destroys or damages that material (e.g., a semi- parallel on the same sensor signals; thus, each sensor conductor junction). Lesser amplitudes may not cause has a corresponding dedicated TPM and digitizer pair. damage. The peak amplitude of voltage or current is the quantity of specific interest in this case, and is provided DIGITIZERS – The waveform digitizers allow users to directly by the TPM. Overenergy damages devices by view the time-domain waveforms from the EM sensors. what is essentially a thermal process, namely, local over- The digitizers sample and store waveforms from the sen- heating of a material in an adiabatic fashion, causing per- sors at up to 500 MSamples/s. As with all digitizing sys- manent damage or degradation [5]. In this case, the peak tems, there are limits on the data transfer rates and amplitudes are not as important as the total energy; that subsequent rearming times that may cause critical level is, a transient with low peak amplitude, but with a long transients to be missed. Even with state-of-the-art tech- duration, can also cause significant damage. The TPM nology, this "dead time" is at best approximately 50 ms computes the total energy in a transient by squaring and (for a 4 MSample record), and can be more than an order integrating the signal from a sensor (in the analog of magnitude worse if multiple digitizers trigger and have domain), resulting in a direct measurement of total to compete for the same bus and memory resources. energy. 2 2 In addition to peak amplitudes and energies, the new screen is shown in Figure 2.1 The right side of the screen TPM provides a coarse spectum analyzer-like display shows plots of TPM data from four sensors. The lower left that provides the peak power in five frequency bands: corner of the display contains a real-time "traffic light" that 10 kHz to 100 kHz, 100 kHz to 1 MHz, 1 MHz to 10 MHz, is initially green and turns yellow or red when user- 10 MHz to 100 MHz, and 100 MHz to 250 MHz. This defined thresholds are exceeded. The upper left portion information is important in assessing the general spectral of the screen contains the tree control used to navigate content of the transient signals and potential coupling to the site and access the data. other systems. Historically, the rate of change of the sig- Users can filter data of interest by setting two threshold nal (derivative) parameter was used for this purpose; levels of interest for each sensor. The lower threshold is however, we expect this new approach to be much more typically used to indicate "interesting" data, though not immune to the noise present in real-world signals and necessarily data that represent a threat. The higher provide a more accurate characterization of the transient. threshold is typically used to indicate data that exceed a The appendix to this paper shows actual lightning- dangerous level. These thresholds have the colors yellow induced transient data obtained during prelaunch opera- and red, respectively, associated with them. The lower tions using the transient pulse monitoring system left corner of Figure 2 shows the traffic light that indi- (TPMS)—the predecessor to OLMS based entirely on cates, in real time, when these thresholds are exceeded. TPM technology. Users can use the Details button to see what threshold criterion caused the color indication. When satisfied, the NETWORK – The sensor station transmits all raw sensor user presses the Reset button to turn the indicator green data collected from the digitizer and TPM subsystems to and prepare for new events. the master station for processing and storage. This is This traffic-light display is most useful in a real-time mode accomplished over a standard Ethernet computer net- of operation, such as in a control room, where the data work. In the event of network failure, the sensor station screen is active 24 hours a day and a user checks the automatically stores sensor data locally until connectivity indicator periodically. More often, perhaps, a remote user with the master station is restored. When connectivity is would not be continuously connected to OLMS but, restored, the sensor station uses the full available net- rather, would check about once a day for new data. The work bandwidth to catch up to real-time operation. right frame of Figure 3 illustrates a feature of OLMS that supports this method of use. The OLMS remembers SELF-TEST – The sensor station includes a built-in arbi- when the system was last accessed by the user and, trary waveform generator for system self-test and overall upon login, presents the user with a summary of the performance verification. This source can generate com- events that have exceeded the user-defined thresholds plex waveforms with frequencies up to 500 MHz, thereby since the last time the user was on the system. The dis- exercising the complete frequency range of operation of play in Figure 3 indicates that there were events that the OLMS. Upon user software control, this source can exceeded the thresholds for positive peak values of the be automatically switched in and the OLMS can be thor- umbilical shield current. Red and yellow indicators in the oughly tested in situ. leftmost column indicate which threshold was exceeded, and the remaining columns indicate the time and magni- MASTER STATION – The entire OLMS is controlled tude of the parameter. What is not immediately apparent from the master station, including sensor station configu- from the static display is that the red and yellow indica- ration, self-testing, and general OLMS administration. tors are web links that take the user directly to the data The master station is also the source of data for all users. that exceeded the given threshold. Raw data from the sensor station are processed into engineering units and stored in a database in the master The data can be viewed on-line in tabular or graphical station. The master station uses web server technology form and can also be downloaded to the user's computer to make the data available to users. Users can access for further processing. There are a number of other cus- OLMS data by using any modern web browser (e.g., tomizable features for the user that are accessible Microsoft Internet Explorer or Netscape Navigator) on through the tree control in the upper left frame. Ultimately, any computer platform that supports these browsers. The users have access to every piece of datum taken by the master station is connected to the Internet and thus can system via the web browser interface. be accessed by authorized users from anywhere in the world. SOFTWARE The software interface for OLMS provides a straightfor- 1. No OLMS are yet operational; thus, no operational data are ward yet powerful way to access the data. Users connect available. The data used for illustration purposes are actual to the master station with a standard web browser to view data collected by the TPMS, the predecessor to the OLMS, OLMS data and can view those data in real time from during a period of nearby lightning activity. These data have been imported into the OLMS for test and demonstration pur- anywhere with Internet connectivity. A sample data poses. 3 2 The software is also tailored to provide maximum flexibil- CONTACT ity and extensibility of the system. Although the maximum number of sensor channels per sensor station is sixteen, Paolo G. Sechi additional sensor station chassis can be added; the soft- SRI International ware makes their operation transparent to the user. This 333 Ravenswood Avenue allows monitoring of a virtually unlimited number of sen- M/S 404-77 sors. Menlo Park, CA 94025 Voice: (650) 859-4223 DEPLOYMENT PLANS Fax: (650) 859-6259 Five OLMS are currently being prepared for installation, beginning in August 1999, at five sites in the United States, to support spacecraft on a variety of launch vehi- cles. The systems are expected to operate continuously, providing a wealth of data of scientific interest. CONCLUSION With OLMS, the real-time monitoring of the prelaunch EM environment of spacecraft systems is possible. OLMS will provide valuable information to allow informed launch decisions and minimize unnecessary launch delays. OLMS will also improve the understanding of lightning- induced transient coupling and electronic system dam- age and upset. ACKNOWLEDGMENTS OLMS is being developed in partnership with Lockheed Martin, under contract for the United States Government. The authors wish to thank the individuals from both orga- nizations that have lent their support and assistance to the OLMS program. REFERENCES 1. G. Baker, J. P. Castillo, and E. F. Vance, "Potential for a Unified Topological Approach to Electromagnetic Effects Protection," IEEE Transactions on Electro- magnetic Compatibility, Vol. 34, No. 3, pp. 267-274, August 1992. 2. E. F. Vance, "Evolution in Interference Control," Pro- ceedings of the Second International Conference on Electromagnetics in Aerospace Applications, Torino, Italy, 17-20 September 1991. 3. United States Military Standard, High-Altitude Elec- tromagnetic Pulse (HEMP) Protection for Ground- Based C4I Facilities Performing Critical, Time-Urgent Missions, MIL-STD-188-125, Appendix B, 26 June 1990. 4. J. E. Casper, editor, High-Power-Microwave Harden- ing Design Guide for Systems, Volume I: HPM and Interpreting Hardening Requirements, U.S. Army Harry Diamond Laboratories, Adelphi, Maryland, HDL-CR-92-709-5, April 1992. 5. D. C. Wunsch, and R. R. Bell, "Determination of Threshold Failure Levels of Semiconductor Diodes and Transistors Due to Pulse Voltages," IEEE Trans- actions on Nuclear Science, Vol. NS-15, pp. 244-259, December 1968. 4 APPENDIX 2 Prior to the development of the present OLMS, the The differences in the relative field-strengths measured TPMS, based entirely on TPM technology, was deployed by these sensors are a result of variations in the location to support a number of launches. Figure 4 illustrates a of lightning events in the moving thunderstorm front and subset of the TPMS data obtained during one of many directional coupling effects caused by launch structure nearby thunderstorms that occurred during those deploy- asymmetries. These selective coupling effects are also ments. evident in the data from the E internal sensor located near the payload and inside an environmental enclosure. Specifically, Figure 4 shows the peak amplitudes of the largest lightning-induced signals measured by each of The remaining data channels show the responses of a B- eight sensors during each one-second period during an dot sensor (also located within the environmental enclo- approximately two-hour thunderstorm period. By far, the sure) and of a set of four current sensors used to monitor highest level of activity appears on the sensors labeled total conducted currents on three payload umbilicals and E top and E side. These are broadband, surface- on an umbilical shield ground termination. These data mounted, electric-field sensors located, respectively, on indicate that, during this particular thunderstorm, despite the top and side of the launch vehicle UT and exposed its proximity and severity, only certain lightning events directly to external incident fields. These sensors are typ- couple efficiently to the payload umbilicals, and that the ically used as a reference to confirm that signals detected resulting signals can be measured effectively. internally are a direct result of external lightning-related fields, and, also, to quantify the incident field strength. 5 2 Figure 1. On-line lightning monitoring system architecture. 6 2 Figure 2. OLMS data display. 7 2 Figure 3. OLMS event display. 8 2 Figure 4. TPMS data with nearby lightning activity. 9