October 2009 Meeting Summary

On October 23, 2009, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA, to listen to a presentation by Dr. Naser El-Sheimy of the University of Calgary. An abstract of the talk and a short biography follow, and the slides used during the meeting are available.

Capsule Biography of Prof. El-Sheimy:
Dr. Naser El-Sheimy is Professor at the Department of Geomatics Engineering, at the University of Calgary. He holds a Canada Research Chair (CRC) in Mobile Multi-sensor Systems and the scientific director of Tecterra. His research interests include multi-sensor systems, mobile mapping systems, estimation techniques, real-time kinematic positioning, and digital photogrammetry and their applications in transportation, mapping and Geospatial Information Systems (GIS). Prior to joining the University of Calgary, Dr. El-Sheimy held the position of VP Research and Development with VISAT Technologies Inc., a high-tech company in Montreal. Through this position Dr. El-Sheimy envisioned, implemented and directed the research and development of several commercial-grade systems for processing and georeferencing of close range digital imagery, automated 3D mapping, and GIS applications. He has developed software packages for integrating, synchronizing, calibrating, and georeferencing digital frame images using GPS/INS systems. These packages are being used in land-based Mobile Mapping Systems for numerous GIS and mapping applications and are currently commercialized through the university of Calgary technology office.

Dr. El-Sheimy published a book and over 300 papers in academic journals, conference and workshop proceedings, in which he has received over 12 national and international paper awards. He organized and participated in organizing many national and international conferences. He is the Principal Investigator (PI) and Co-PI of over 50 research projects and has successfully led several highly competitive grants such as the Canadian NSERC Strategic grants, Alberta Research excellence (REE), Canadian Network Centers of Excellence (NCE), The Canadian Foundation for Innovation (CFI) , Intellectual Infrastructure Partnership Program (IIPP), Coordination of University Research for Synergy and Effectiveness (COURSE), etc..

Dr. El-Sheimy is currently a member of the Editorial Board of Journal of Survey Review, member of the Alberta Geomatics Group Board of Directors, Chairman of the Special Study Group on “Mobile Multi-sensor Mapping Systems”, of the International Association of Geodesy, Chairman of the International Society for Photogramtery and Remote Sensing (ISPRS) Working Group I/V on “Integrated Mobile Mapping Systems”, Chairman of the International Federation of Surveyors/Fédération Internationale des Géomètres (FIG) Working Group C5.3 on “Kinematic and Integrated Positioning Systems, member of the Association of Canada Lands Surveyors, Board of Examiners – Western Canadian Board of Examiners for Land Surveyors, Atlantic provinces Board of Examiners for Land Surveyors, Technical Committee Member of the ASPRS Direct Georeferencing Committee, regular reviewer for the Journal of Geodesy, Journal of Photogrammetric Record, the Photogrammetric Engineering and Remote Sensing Journal and other scientific journals.

Dr. El-Sheimy has received many significant academic and paper awards including the ISPRS Best Young Author Prize, the IEEE VNIS Best Paper Prize, The ION Best Paper Award, the ION/IEEE best paper award, and the ISPRS Best Young Author Award, and Calgary Herald – Canadian Hunter Exploration Ltd. – Petro Canada Young Innovator Award.

Tecterra
Tecterra is a new national center of excellence located in Alberta, Canada that has partnered with the applied geomatics research community and corporate partners in the advanced technology, agricultural, forestry, environment, oil and gas industries to integrate remote sensing, sensor systems, mapping and IT infrastructure solutions. Tecterra has been created to explore, develop, integrate and facilitate the commercialization of new services and products that can address resource management challenges and emerging geospatial opportunities. Tecterra will conduct leading-edge applied research to drive the deployment of geospatial applications and systems with its partners in Alberta, Canada and world-wide.

Abstract of Prof. El-Sheimy’s Talk:
Slides: The Promise of MEMS to The The Navigation and Mobile Mapping CommunityCommunity
Cost and space constraints are currently driving manufacturers of location based services and Mobile Mapping Systems (MMS) to investigate and develop next generation of low cost and small size navigation systems to meet the fast growing mobile mapping and location services market demands. Advances in Micro-Electro-Mechanical Systems (MEMS) technology have shown promising light towards the development of such systems. MEMS are integrated micro devices or systems combining electrical and mechanical components whose size ranges from micrometers to millimeters. MEMS is an enabling technology and the MEMS industry has a projected 10-20% annual growth rate to reach 200 billion US$ market by 2009. Advances in MEMS technology combined with the miniaturization of electronics, have made it possible to produce chip-based inertial sensor for use in measuring angular velocity and acceleration. These chips are small, lightweight, consumes very little power, and extremely reliable. It has therefore found a wide spectrum of applications in the automotive and other industrial applications. MEMS technology, therefore, can be used to develop next generation navigation and Direct Georeferencing (DG) systems that are inexpensive, small, and consume low power (microwatt). However, due to the lightweight and fabrication process, MEMS sensors have large bias instability and noise, which consequently affect the obtained accuracy from MEMS-based IMUs. For land navigation applications, introducing auxiliary velocity update in the body frame, (e.g. non-holonomic constraint and odometer signal) is an option to solve the problem.

The promise of MEMS technology to the navigation community has been germinating over the last decade, and current advances bring the field to the very cusp of fruition. In this presentation, recent developments in MEMS-based inertial sensors will be reviewed and some emerging applications and future trends will be discussed. The presentation will use an example of a MEMS-based IMU as an optimistic promise to the navigation community.

August 2009 Meeting Summary

On August 30, 2009, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. 28 people were attendance to listen to a presentation by Slobodan Nedic. A short biography and abstract of the presentation follows, and the slides used during the meeting are attached.

Capsule Biography of Slobodan Nedic:
Slobodan Nedic is an independent consultant in communications and GPS technologies. He received the BS and MS degrees in EE from Belgrade University in 1974 and 1980, respectively. During the academic year 1981/82 he was a guest researcher at the Technische Hochschule in Darmstadt, Germany. There, he was investigating delay-spread and impulse noise resistance of time- and frequency-domain differential PSK in the context of OFDM. Most of his career was spent with the Michael Pupin Institute in Belgrade working on telephone and HF voice-band modem design and production.

He has been with NEC (NEC C&C Central Research Laboratory in Kawasaki, Japan and the NEC Research Laboratory in Princeton, NJ), working on R&D of DAB, cellular and H/ADSL systems. His latest full-time job was with the SiRF Technology Systems Group in Santa Ana, CA, where he worked on dual antenna indoor GPS reception, excision-based anti-jamming, and urban canyon multipath mitigation.

He has consulted for NEC, ASTRI, Airvana and Boeing on 4G system accessing formats, MIMO VDSL system, evaluation of WiMAX technology and GPS retransmission systems, respectively.

Abstract of Mr. Nedic’s Talk:
Slides: On GPS/GNSS Signal Multipath Modeling in Dynamic Environments
This presentation scrutinizes the traditionally used multi-path modeling, noting its failure to capture propagation mechanisms of importance for GPS receiver operations in dynamic environments. An enhanced multipath model is proposed that directly extends the LOS signal propagation model. The crucial point is that the total delay encountered in reception of a SV transmitted code is a sum of instantaneous physical delays and accumulated code delay due to the ‘code Doppler’. The result is that in some situations the correlation peak pertaining to a multipath signal may be measured before the LOS one. This situation is qualitatively and quantitatively evaluated for a simplified scenario of an aligned array of transmitter, reflector and receiver, with the latter two in relative motion. The lessons learned from an experiment conducted to provide the experimental proof for such an effect are provided, and the model is further applied to a set of processed IF samples to explain peculiarities of some urban environment measurements. A suggestion is made of the origin of partially unexplained multipath components obtained by high resolution measurements in data collected in aviation landing measurements

July 2009 Meeting Summary

On July 30, 2009, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. 43 people were attendance to listen to a presentation by James Kain of GeoVantage. A short biography and abstract of the presentation follows, and the slides used during the meeting are attached.

Capsule Biography of James E. Kain 
Mr. Kain has practiced the art of Kalman filtering and Navigation since the 60’s beginning at Draper Laboratory while he was at MIT, followed by five years at Johns Hopkins Applied Physics Laboratory, and then through 22 years at TASC (now Northrop Grumman). Since the early 90’s he has founded multiple small commercial businesses all with core technology fueled by modern estimation and aided navigation. His long experience with the Kalman filter has provided a unique insight into the applications issues of what he considers “the most important algorithmic development of the 20th century”. Over his tenure at GeoVantage since 1998, he has pursued breakthrough methods to bring affordable precision geospatial information to domestic and international markets.

Abstract of Mr. Kain’s Talk
Slides: Kalman Filter Implementation with Improved Numerical Properties
Mr. Kain will provide a two-part presentation of the work that he and others have done in developing a new mechanization of robust, high rate Kalman filter signal processing algorithms and will present their application in remote sensing. His company, GeoVantage, has pioneered remote sensing with very low cost platforms which compete in performance with very much more expensive platforms and which provide very rapid access to users in agriculture, forestry and mapping solution providers.

The quote below provides a preview of his signal processing topic:

“The Kalman filter’s generalized model-based approach to optimal estimation would appear to be ideal for accelerating the transition from the conceptual definition of an estimation problem to final algorithm implementation – bypassing the selection and testing of alternative suboptimal designs. This has not been the case for engineering disciplines such as communications and speech processing. We offer two reasons:

  • Kalman filter robustness issues remain even after over 30 years of refining the details of implementation.
  • Processing speed for Kalman filter solutions cannot approach the many-MHz update cycle times demanded for modern signal processing algorithms.”

Mr. Kain’s second topic addresses affordable mapping, summarized as:

Google Earth and Microsoft’s Virtual Earth have legitimized Remote Sensing “for the rest of us”. Precision spatial information has demonstrated broad consumer interest and georegistered imagery holds the key for immediate visual feedback. The merging of precision navigation and digital imagery transforms pictures into information. Extreme precision GPS, MEMS inertial technology, and the continued acceleration of digital imagery capability suggest a ubiquitous imagery-based web-delivered telepresence. Mr. Kain will discuss the current GeoVantage geospatial markets, technology directions that will change this landscape and soon-to-emerge systems that will bring the planet to your desktop.

June 2009 Meeting Summary

On June 30, 2009, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation by Per Enge of Stanford University entitled “On Location at Stanford University”. A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Capsule Biography of Dr. Per Enge 
Dr. Per Enge is the Kleiner-Perkins Professor in the School of Engineering at Stanford University, where he is also the Director of the GPS Research Laboratory. The GPS laboratory pioneers satellite-based navigation systems for aviation and maritime use. Two of these systems are in widespread use today, and a third will be deployed in 2009. Per Enge has received the Kepler, Thurlow and Burka Awards from the Institute of Navigation for his work. He is also a Member of the National Academy of Engineering and a Fellow of the ION and the IEEE. He received his PhD in Electrical Engineering from the University of Illinois in 1983, where he designed and analyzed an orthogonal signal set for code division multiple access communications.

Abstract of Professor Enge’s Talk
Slides: On Location at Stanford University
This talk will provide quick sketches of three location projects that are current at Stanford.

The first concerns itself with the use of GPS for aircraft navigation during the approach and landing phases of flight. It includes results on the use of receiver autonomous integrity monitoring for aircraft approach guidance, and the use of ground based augmentation for aircraft landing.

The second will focus on the combined use of laser altimetry and cold atom gravimetry for the detection of underground inhomogeneities.

The third will introduce the idea of using GPS to enable a marketplace where commuters can sell their “right to congest.”

March 2009 Meeting Summary

On March 11, 2009, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation from GPS Space Wing Chief Engineer Col(S) David B. Goldstein on the subject of the new GPS III Space Vehicle and Modernization. 25 people were in attendance for the meeting. A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Capsule Biography of Col(S) David B. Goldstein
Colonel Select David B. Goldstein is well familiar with the many aspects of the GPS program and is the Chief Engineer for the Global Positioning System (GPS) Space Wing at Los Angeles AFB, CA. Prior to his appointment as Chief Engineer, David was the Commander of the 4th Space Launch Squadron, Vandenberg AFB, CA. In a previous tour of duty at LA AFB, David also served as Chief: Engineering Branch Office, NAVSTAR Global Positioning System Joint Program Office. David was commissioned as an USAF officer in 1988 with a BS in Engineering Science from the US Air Force Academy. He pursued graduate work obtaining his Masters Degree in Aerospace Engineering from the University of Houston and obtained a Ph.D. in Aerospace Engineering from the University of Colorado.

He has experience in many areas, from leading large teams conducting satellite and launch systems engineering to conducting three years of graduate school research in the use of the GPS for real-time, precise satellite Orbit Determination (OD). He has taught astronautics and built small sats at the United States Air Force Academy. He is experienced in directing ballistic missile, Space Shuttle, and satellite payload integration, launch and on-orbit operations as well as managing and controlling contracts.

Abstract of Col(S) Goldstein’s talk
Slides: GPS III Space Vehicle and Modernization
Colonel (S) Goldstein will provide an overview of the new GPS Block III satellite series development approach as well as a description of the modernized capabilities that will become available in the future. The talk will describe the spiral development approach beginning with GPS Block IIIA, and the incremental increase in capability with each new series of GPS III Block vehicles, the Block IIIB and IIIC.

February 2009 Meeting Summary

On February 18, 2009, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation from Dr. Bob Norris of John Deere on an unmanned ground vehicle (UGV) named the R-Gator. 28 people were in attendance for the meeting. A short biography and abstract of the meeting follows, and the slides and video used during the meeting are attached.

Following the talk, Chuck Morton, NavCom’s Manager of StarFire System Operations, provided a short guided tour of the StarFire Network Data Processing and Control Center. The StarFire Network gathers information from GPS monitoring receivers around the world and constructs differential corrections and integrity monitoring of the GPS satellite system, in real time. These corrections and health data are broadcast around the world via a network of 6 INMARSAT satellites. StarFire equipped GPS receiver routinely achieve 0.1 m or better navigation performance. The Torrance Control Center is one of two completely-redundant processing centers that have allowed the StarFire Network achieve better than 99.9% up time

Capsule Biography of Dr. William R. Norris
William R. (Bob) Norris is currently the Business Manager of a John Deere robotic product known as the “R-Gator”. In this role, he is performing the functions of Business Development, Marketing, Sales, Program Management, Service and Support. He has been with the product since its inception. Bob has previously served as a researcher, systems engineer, program engineer, program manager and now business manager.

Bob received his BS, MS and PhD degrees at the University of Illinois, Champaign-Urbana, where he worked at the National Center for Supercomputer Applications (NCSA). His focus was in Control Systems, Systems Engineering and Artificial Intelligence. He recently completed his MBA at Duke University, focusing on General Management and High Tech Marketing. Bob was a paratrooper with the 82nd Airborne Division in Operation Desert Storm.

Abstract of Dr. Norris’s Talk
Slides: R-Gator Presentation
The R-Gator (Robotic Gator) is an advanced ground vehicle system, capable of robust operations in both manned and unmanned modes. The combat proven John Deere M-Gator serves as the basic mobility platform, allowing existing logistics, maintenance, and training investments to be leveraged for reduced cost and ease of deployment. The R-Gator’s capabilities include manual operation, several forms of tele-operation via joystick, map based GPS waypoint navigation and path teaching and playback.

The primary objective of the R-Gator system is to remove the user from hazardous, non-combat related missions. The ability to perform a variety of robotic utility tasks, in hostile environments and over complex terrain, reduces the users’ exposure to hazards. The secondary objective of the R-Gator system is to serve as a host for payloads. Under its current configuration, the R-Gator provides payload space, 1400lb carrying capacity, a limited power supply, an ethernet and CAN interface for access to vehicle network communications.

Bob will provide an update on the R-Gator program. He will also discuss the challenges involved in the localization and navigation of a large (1400lb) unmanned ground vehicle and how Deere’s solutions enable the accurate localization, navigation, obstacle detection and avoidance of the R-Gator.

December 2008 Meeting Summary

On December 16, 2008, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA.  The meeting included a two-part presentation from Dr. Chris Bartone of Ohio University covering The ION Virtual Museum and eLoran.  About 25 people were in attendance for the meeting.  A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Capsule Biography of Dr. Chris Bartone
Dr. Chris G. Bartone, P.E. is an Associate Professor at Ohio University with over 25 years of profession experience in communications, navigation, and surveillance systems.  He received his Ph.D.EE from Ohio University in 1998, an MSEE from the Naval Postgraduate School in 1987, and BSEE from Penn State in 1983.  He previously worked for the Naval Air Warfare Center, performing RDT&E on CNS systems.  Chris received the RTCA William E. Jackson Award in 1998 for his outstanding contribution to aviation in the area of DGPS.  At Ohio University, Dr. Bartone has developed and teaches a number of GPS, radar, antennas, and wave propagation classes.  His research concentrates on all aspects of navigation.  He is a member of the ION and the IEEE.  He is very active with the ION; chaired several programs; Chair, ION Outreach Committee; and Editor, ION Virtual Navigation Museum.  Chris is a licensed professional engineer in the state of Ohio.

Part I – The ION Virtual Navigation Museum
Slides: ION Outreach Committee
Dr. Bartone is the Chair of the ION Outreach Committee, and Editor of the ION Virtual Navigation Museum (VNM).  While the ION is a non-profit professional society dedicated to the advancement of the art and science of navigation it also recognized the importance of preserving previous art and science in navigation.  The ION VNM was established in September 2006 to allows visitors to read descriptions, view photographs, and obtain detailed information on a navigation device, systems, components, and/or methods in a convenient on-line format.  The ION VNM link is: www.ion.org/museum.   Chris will discuss the foundation of the museum, how it is organized, and administered.  He will discuss some of the interesting entries into the museum and the various collaboration efforts ongoing.  The presentation will be a combination of presentation slides on on-line illustrative.

Part II – eLoran
Slides: eLoran Presentation
Enhanced Long Range Navigation (eLoran) leverages many of the modernization efforts that have been pursued for the traditional Loran-C.  One significant difference between eLoran and Loran-C is the addition of a data channel on the transmitted signal to convey application-specific corrections, warnings, and signal integrity information to the user’s receiver.  Other modernization efforts include going to time-of-transmission (TOT) control and the implementation of new transmitter, all-in-view receiver, and antenna equipment.  Dr. Bartone will provide an overview of the modernization and eLoran efforts as well as the Loran research efforts ongoing at Ohio University.  Chris will present details on the Loran Propagation Model development and validation for additional secondary factor predictions and measurements, Loran noise characterization, and antenna H-field characterization for Loran.

November 2008 Meeting Summary

November 2008 Meeting Summary
On November 12, 2008, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation from Dr. Svenja Knappe of NIST entitled Chip Scale Atomic Clocks. A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Capsule Biography of Dr. Svenja Knappe
Svenja Knappe received her Ph.D. from the University of Bonn, Germany, in 2001, for her research on coherent population trapping for atomic clocks and magnetometers. As part of her graduate work, she worked on cooling and trapping of single atoms. Since 2001, she has worked at the National Institute of Standards and Technology (NIST) in Boulder, CO. Her current research interest is the miniaturization of atomic sensors. She developed the first microfabricated atomic vapor cells and laser wavelength stabilization, as well as chip-scale atomic clock physics package at NIST. Currently, she works on the development of chip-scale atomic magnetometers.

Abstract of Svenja Knappe’s Talk
Slides: Chip Scale Atomic Clocks
Chip-scale atomic clocks – Chip-scale atomic clocks (CSACs) have rapidly advanced since their proposal in 2001. The combination of MEMS fabrication techniques and atomic physics has led to the development of small, low cost atomic clocks with much reduced power consumption. Embedding these clocks in battery-operated portable devices would have many potential applications in the telecommunication and navigation sector. After the initial demonstration of the first microfabricated alkali vapor cells and CSAC physics packages, many improvements have been made in terms of short-term frequency stability, power consumption, and size. By now, this has led to the fabrication of commercial prototypes. Furthermore, some of the fabrication technologies developed for CSACs have been used for other chip-scale atomic sensors, such as magnetometers, wavelength references, and gyroscopes.

September 2008 Meeting Summary

On September 11, 2008, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA. The meeting included a presentation from Dr. Todd Walter of Stanford University entitled The Ionosphere and its Effect on Satellite Navigation. About 50 people were in attendance for the meeting. A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Biography of Dr. Todd Walter 
Dr. Todd Walter received his B.S. in physics from Rensselaer Polytechnic Institute and his Ph.D. in 1993 from Stanford University. He is currently a senior research engineer in the Department of Aeronautics and Astronautics at Stanford University. He is active in the development of the Minimum Operational Performance Standards for WAAS (Wide Area Augmentation System) and co-chair of the WAAS Integrity Performance Panel focused on the implementation of WAAS. He has served as program chair and general chair for the ION’s NTM and GNSS meetings and is currently the western regional vice president. He was a co-recipient of the 2001 ION early achievement award and is a fellow of the ION.

Abstract of Todd Walter’s Talk
Slides: The Ionosphere and its Effect on Satellite Navigation
The ionosphere creates some of the most significant challenges to the use of precise GPS. Its spatial and temporal variations limit the accuracy of position solutions. The uncertainty of its influence limits the availability of high accuracy and high integrity systems. In equatorial areas the ionosphere can cause a form of self-interference, called scintillation, that can prevent the tracking of the signal altogether. Yet, despite these serious obstacles, the ionosphere itself is not well understood. As the use of GPS becomes more demanding and more wide-spread, it is important to examine the ionosphere and understand the range of possible effects.

The FAA has a network of redundant measuring stations throughout North America that has been used to continuously observe ionospheric behavior for the last 8 years. These data have been used to identify the largest gradients observed at middle latitudes.

Our emphasis, in this research, has been on identifying the extreme behavior that, fortunately, occurs rarely over the United States. We have also examined data from other parts of the globe where large variations can be much more common.

A partial solution to the challenges from the ionosphere is under development in the form of modernization of the GPS signals. However, this solution comes at a cost: the combination of signals to create an ionospheric-free measurement greatly inflates the magnitude of other error sources. Users who are particularly affected by the ionosphere will welcome these new signals that will do much to reduce extreme behavior.

This talk will focus on observations of ionospheric effects ranging from typical observed variations to the extreme behavior of ionospheric superstorms. The effects on satellite navigation will be discussed as well as how to place confidence limits on the possible magnitude of its effect.

June 2008 Meeting Summary

On June 25, 2008, the Southern California Chapter of the ION held a meeting, hosted by NavCom in Torrance, CA.  The meeting included a presentation from Dr. Chun Yang of NIST entitled Software GPS Receivers: Some Recent Developments and Trends.  A short biography and abstract of the meeting follows, and the slides used during the meeting are attached.

Brief  Resume of Dr. Chun Yang
Dr. Chun Yang has been with Sigtem Technology, Inc., since 1994 where he works on adaptive array and baseband signal processing for GNSS receivers and radar systems as well as on nonlinear state estimation with applications in target tracking, integrated inertial navigation, and information fusion. Dr. Yang is also an adjunct professor of Electrical and Computer Engineering at Miami University. He is the co-inventor of seven issued and pending U.S. patents. Dr. Yang received his Docteur en Science from Université de Paris-Sud, Orsay, France, in Sciences Physiques in 1989 and his Bachelor of Engineering from Northeastern University, Shenyang, China, in 1984. He is the co-author of an ION-GNSS best presentation paper and an ION AM/IEEE PLANS best track paper, and the co-recipient of ION Samuel M. Burka Award.

Abstract of Talk:
Slides: Software GPS Receivers: Some Recent Developments and Trends
More and more processing functionalities of a GPS receiver are implemented in software. Given this trend and with more capable and power-efficient processors over the horizon, a natural question to ask at this juncture is how to configure a software baseband processor, not just mimicking hardware-implemented functionalities, to best use of signals available.  This is particularly well-timed at the dawn of multi-constellation GNSS with a diversity of frequencies and codes.  This presentation will start with a brief review and then examine an exemplary state of the art software GPS receiver in detail.  It will focus on two recent developments.  One is a frequency-domain baseband processor that implements satellite signal channel impulse response vs. conventional correlation.  The other is on-line adaptive code replica synthesis, which can be used to suppress multipath and multi-access interference.  The presentation will end with some probing thoughts on standardization.