International Technical Meeting (ITM)

ITM Session Topics

Peer review available

Innovations in Navigation for Smartphones and Wearables
Applications requiring reliable positioning solutions in smartphones and wearables. Enhanced positioning techniques in smartphones and wearables for improved indoor, outdoor, and urban-canyon navigation. Improved stochastic modeling of GNSS observables. Algorithms and multi-sensor fusion for enhanced accuracy in varied environments. Use of smartphone raw GNSS measurements for scientific applications in geosciences. Detection and mitigation of jamming and spoofing threats in smartphone-based positioning systems. Quality assessment of GNSS antennas in smartphones and wearables, including evaluation of antenna phase center offsets and variations. Navigation for AR and VR using smartphones.
Session Chairs:
Dr. Christina Selle, Apple
Dr. Li-Ta Hsu, Hong Kong Polytechnic University

Alternatives, Backups, Complements to GNSS
Alternative PNT solutions for terrestrial applications such as aviation, maritime, road, and rail. Technologies addressing the vulnerability of GNSS users to natural threats and security vulnerabilities. New positioning methods and technologies from existing and emerging terrestrial and space-based transmitters. Technologies that complement or replace GNSS when denied. Solutions for terrestrial multipath and degenerate geometries on positioning. Examination of atmospheric distortions and integrity monitoring for terrestrial radionavigation.
Session Chairs:
Dr. Tyler Reid, Xona Space Systems
Christian Ardito, StarNav

GNSS Security: Interference, Jamming, and Spoofing 1
Detection, characterization, and geolocation of intentional and unintentional interference. Mitigation strategies and improved robustness against spoofing, jamming, and general interference. Signal-to-noise ratio characterization in the presence of interference and its effects on GNSS receivers. Development of software and hardware solutions, including signal processing and authentication. Utilization of backup and complementary PNT technologies. Applications in robust positioning and secure time transfer. Threat modeling and analysis of GNSS disruption events. Spectrum monitoring and localization of interference sources using ground, airborne, and spaceborne receivers. Establishment of networks for spectrum monitoring. Use of smartphone GNSS data for spectrum monitoring. Techniques to enhance GNSS robustness through advanced signal processing, authentication, and complementary PNT methods.
Session Chairs:
Zixi Liu, Stanford University
Dr. Jianming She, The MITRE Corporation

GNSS Security: Interference, Jamming, and Spoofing 2

Session Chairs:
Dr. Jianming She, The MITRE Corporation
Zixi Liu, Stanford University

Next-Generation Satellite Navigation Technology
Innovations in future generation satellite navigation technology; advancements in satellite constellations. Strategies and approaches for the interoperability and compatibility of GNSS constellations. Multi-layer satellite navigation: Development of new (institutional and private) navigation systems and extension of GNSS into Low Earth Orbit (LEO) and/or other orbits. Adaptations for fused broadband and navigation satellite systems. Updates on constellation characteristics and programmatic elements, along with ground control and monitoring segments. Evaluation of the performance of new satellites and services. Examination of RF compatibility, mutual interference, and antenna pattern characterization. Enhancements in GNSS signal structure through codes and data messages. Cutting-edge technologies, including highly stable frequency standards on-board navigation satellites and intersatellite links.
Session Chairs:
Sam Morgan, University of Texas at Austin
Dr. José-Ángel Ávila-Rodríguez, European Space Agency

PNT Solutions for Space Applications
This session focuses on emerging technologies in space navigation and positioning systems at locations near Earth (e.g., LEO, GEO, HEO) and beyond (e.g., Moon, cis-lunar, Mars, asteroids). Types of navigation techniques and technologies of interest include, but are not limited to, GNSS precision navigation, relative navigation techniques, snapshot-based positioning, signals of opportunity utilization, electro-optical systems, and cooperative positioning. All aspects of enhanced and next-generation navigation systems from design, testing, and performance will be covered. Other applications to spotlight for enhanced navigation techniques are satellite constellation build-up and maintenance, interplanetary missions, and celestial and docking maneuvers.
Session Chairs:
Robert McBride, Blue Origin
Dr. Rebecca Bishop, The Aerospace Corporation

Sensor-Fusion for GNSS-Challenged Navigation
Integration of data from multiple sensors and information sources in GNSS-challenged environments. Application of estimation theories, algorithms, and data processing techniques. Testing and results from integrating diverse sensors: GNSS, inertial sensors, odometers, magnetometers, radar, lidar, cameras, barometers, map, infrared, ultrasound sensors, signals of opportunity (SOOP) and non-RF aiding. Navigation strategies for urban canyons, indoor settings, and GNSS-denied environments. Use of low-cost devices for pedestrian and automotive applications. Modeling environmental effects on navigation sensors, including magnetic and gravity models.
Session Chairs:
Dr. Ciro Gioia, European Commission Joint Research Centre
Dr. Andrey Soloviev, QuNav

Advancements in Navigation Algorithms
Application of modern machine learning techniques to enhance navigation, including deep neural networks, boosting, graphical models, and both interpretable and unsupervised learning methods. Algorithms and techniques leveraging network connectivity to assist and improve navigation. Innovative estimation methods such as distributed state estimation, advanced filtering, and integration of 3D models, landmarks, and other data sets. Utilization of cloud and crowd-sourced data for navigation. Development of algorithms for new applications and fresh approaches to modeling and numerical challenges in navigation and positioning. Robust positioning techniques suitable for challenging environments. Collaborative and cooperative positioning algorithms and theories. 
Session Chair:
Dr. Todd Walter, Stanford University

Atmospheric Effects, GNSS Remote Sensing, and Scientific Applications
GNSS technologies used for environmental and scientific monitoring, measuring atmospheric effects, and sensing Earth’s surface properties and changes. Applications in radio occultation, ionospheric TEC and scintillation, and detecting geophysical events such as earthquakes and volcanic eruptions. GNSS reflectometry for environmental monitoring of soil moisture, vegetation, ocean wind, ocean wave, tsunamis, hurricane, flood surveillance, ice, and inland water bodies. Novel GNSS applications exploring gravitational measurements and dark matter detection.
Session Chairs:
Yu-Fang (Frank) Lai, Stanford University
Dr. Jade Morton, University of Colorado, Boulder

Autonomous Navigation and Safety-Critical Applications
Navigation systems for assisted and autonomous vehicles and mobile platforms. Integrity monitoring for safety-critical applications using GNSS and additional sensors. Support through assistance and cloud-based technologies for reliable and secure autonomous systems. Innovative integrity algorithms, Advanced Receiver Autonomous Integrity Monitoring (ARAIM), novel error models taking into account no gaussian errors and time correlation effects. Enhanced safety, availability, and efficiency in guided vehicle systems and pilot assistance within demanding environments. Safety protocols, integrity standards (e.g., automotive ISO SOTIF) and certification criteria for autonomous navigation and guidance systems.
Session Chairs:
Andrew Videmsek, Reliable Robotics
Dr. Jose Angel Avila Rodriguez, European Space Agency

GNSS Integrity and Augmentation
Integrity monitoring, fault detection, and exclusion in GNSS augmentation systems. Identification and modeling of GNSS faults, including satellite and constellation failure modes, as well as external threats like spoofing. Anomaly detection and protection level characterization, testing, and results. Requirements for receiver-based integrity to enhance reliability, safety, and efficiency. Dissemination of integrity support information, impact of data channel capacity and latency. Development of novel augmentation systems and multi-GNSS solutions including GBAS and SBAS, but also urban augmentation and mitigation of multipath. Challenges in providing integrity in multi-frequency/multi-constellation services, including DFMC airborne models for antenna and measurement errors. Application of high-performance and safety-critical GNSS applications across sectors including civil aviation, automotive, UAVs, rail, and maritime.
Session Chairs:
Dr. Okuary Osechas, ZHAW Centre for Aviation
Dr. Samer Khanafseh, Illinois Institute of Technology / TruNav LLC

Precise GNSS Positioning Applications
Advances in GNSS positioning methods including Multi-GNSS Precise Point Positioning (PPP), Real-Time Kinematic (RTK), PPP-RTK, and network RTK. Development of partial ambiguity resolution techniques and Integer Ambiguity Resolution (IAR) using high precision geodetic-quality and/or low-cost antennas and receivers, including smartphones. Utilization of positioning algorithms with space-based augmentation services like the Galileo High Accuracy Service (HAS). Multi-constellation solutions employing single-/multi-frequency geodetic and/or low-cost receivers/antennas. Characterization and modeling of GNSS satellite clock errors; precise orbit determination for scientific purposes. Interoperability of GNSS correction services with diverse user equipment, ensuring robustness against multipath, interference, and other local effects. Comprehensive GNSS signals and performance characterization and monitoring. Applications of high precision and high integrity GNSS positioning in fields like crustal and structural deformation monitoring, GNSS seismology, atmospheric remote sensing, and precision agriculture. New algorithms and methods enhancing precise positioning techniques and robustness against local environmental effects.
Session Chairs:
Dr. Kaz Gunning, Xona Space Systems
Sandy Kennedy, Hexagon

Receiver Design, Signal Processing, and Antennas
GNSS receiver signal processing techniques for enhanced resiliency in challenging environments such as indoor, urban canyons, foliage, scintillation, high dynamics, and under interference. Design of receivers optimized for modernized GNSS signals. Development and application of software-based GNSS receivers. Enhancements in acquisition and tracking sensitivity, robustness, and accuracy. Mitigation strategies for multipath and non-line of sight signals. Design and evaluation of GNSS antennas and antenna electronics. Optimization of receiver architecture, signal processing and/or antenna for mass-market devices. Calibration processes for multi-GNSS receivers. Utilization of multi-GNSS signal simulators for testing and development.
Session Chairs:
Dr. Yu (Joy) Jiao, Trimble
Dr. Jean-Marie Sleewaegen, Septentrio

Precise Time and Time Interval (PTTI)

PTTI Pre-Conference Tutorials

Tutorial Chair: Dr. Giancarlo Cerretto, Istituto Nazionale di Ricerca Metrologica (INRIM)

1. Microwave and Optical Atomic Clocks: past, present, and future: Dr. Shimon Kolkowitz, University of California Berkeley
2. TAI, UTC, and UTC(k): the role of the time laboratories in the realization of reference time scales: Dr. Jeff A. Sherman, National Institute of Standards and Technology (NIST)
3. GNSS: the importance of timing, best practice in the remote comparison of atomic clocks/timescales, and achievement of traceability to UTC through satellite measurements
4. White Rabbit: technology, applications and best practices in disseminating traceable reference time scales: Javier Serrano, Conseil Européen pour la Recherche Nucléaire (CERN)
5. Low-noise Digital Electronics for Time and Frequency Metrology: Dr. Claudio E. Calosso, Istituto Nazionale di Ricerca Metrologica (INRIM)

PTTI Session Topics

No peer review option

LEO Satellite Timing Requirements and Applications
The advent of proliferated Low Earth Orbit (pLEO) systems enables the realization of effective LEO-based time transfer. In pLEO systems, low-cost small satellites and commensurate access to space allows the rapid fielding of constellations with hundreds of space vehicles (SV). Architectures featuring meshed inter-satellite links allow for the near-immediate propagation of timing corrections to SV clocks, supported by two-way inter-satellite ranging. This also enables robust and resilient terrestrial navigation. The session will capture recent work using pLEO for space-based time transfer to terrestrial user systems. We invite both commercial and defense-oriented space systems to submit papers. Key performance characteristics might include maintaining accuracy when access to UTC is not available, either via GNSS or via space-to-ground links, and reaching ps level time transfer stability.
Session Chair:
Greg Weaver, JHU/APL, SDA

Time and Frequency Transfer for Comparing Clocks with with 10^-18 Uncertainty
Increasingly precise timing is critical for positioning and navigation, as well as networks and telecommunications. Comparing the latest generation of optical clocks to uncertainties of 5×10^-18 is a mandatory criterion for the upcoming redefinition of the SI second. The presentations in this session will report on the newest methods for remote synchronization and syntonization that surpass the performance or reliability of conventional GNSS time transfer. Covering both RF and optical techniques, topics include fiber and free-space links to connect clocks on the ground, in the air, and in space.
Session Chair:
Dr. Nils Nemitz, NICT

Updates from Regulatory Agencies and Institutions Involved with Precise Time and Frequency Metrology
Time and Frequency (TF) metrology is not limited to National and Designated Institutes, but has a global impact across diverse areas of science and industry. This session will present recent developments related to the domain of TF in various international organizations, specifically focusing on aspects that enhance and improve the utilization of UTC and SI second. We invite organizations such as the BIPM, IERS, IAU, IGS, IGU, ITU, ISO, ETSI, IEEE, CNES, NASA, ESA, ASI and others to inform the audience about their activities and impact on users in the time and frequency field. We invite speakers to address the standardization and calibration issues for topics such as leap second implementation, adoption of optical clocks, high precision network synchronization, as well as to present on the advancement of timing in astronomy/astrophysics, geodesy, and fundamental physics.
Session Chairs:
Dr. Marina Gertsvolf, NRC
Edoardo Detoma, Consultant

Activities at National Metrology Institutes
This session welcomes Time and Frequency Laboratories operated at National Metrology Institutes (NMIs) providing an opportunity to present advancements and updates in precise timing. It will involve topics such as methods used in the generation of UTC(k), presentation of timescale hardware and algorithms used or developed. The various Time and Frequency services offered by NMIs and how these services are administered as well as information monitored for each service.
Session Chairs:
Aidan Montare, NIST
Terrence Jones, Bureau of Standards Jamaica

Advanced and Future Clocks
Clocks are needed for timekeeping, navigation, positioning, communication, science, and exploration in both terrestrial airborne and space applications. The development of clocks is driven by technological advances in these areas that push for devices with unique combinations of performance, reliability, robustness, and SWaP. This session considers clocks that offer an advantage over existing clocks with form factors larger than chip-scale atomic clocks. Presentations may be on any type of advanced clock in its present or future form. Examples of these clocks include: hot and cold atom clocks, ion/molecular clocks; microwave, terahertz and optical clocks, optical frequency combs, and cavity stabilized ultra-stable lasers; cryogenic sapphire oscillators; and optically pumped clocks. 
Session Chairs:
Dr. John Elgin, Air Force Research Laboratory
Dr. Daphna Enzer, Jet Propulsion Laboratory, California Institute of Technology

Environmental Sensitivity of Clocks and Timing Systems
The release of the IEEE 1193 "Guide for Measurement of Environmental Sensitivities of Frequency Standards" provides an opportunity to improve the accuracy, relevance, and usability of specifications for oscillators and timing systems. IEEE 1993 provides clear definitions and distinction between total sensitivity over a parameter range and linearized sensitivity coefficient over a defined range. The publication of comprehensive sensitivity coefficients provides systems' designers and integrators with valuable input to accurately model system performance in environmentally dynamic environments. This session encourages submissions presenting IEEE 1193 influenced measurements of clocks and timing systems, comparisons of Total Sensitivity measurements with Sensitivity Coefficients, and demonstrations of system modelling and integration.
Session Chairs:
Dr. Daniele Monahan, The Aerospace Corporation
Christopher Higgins, Microchip

GNSS Systems Timing Architectures and Capabilities
Timekeeping is the heart of GNSS, and maintaining it requires a complex system with elements in the space, control, and user segments. This session will focus on how present and proposed GNSS constellations maintain time and frequency, and how they provide users with a robust position, navigation, and timing signal. Papers presenting innovative concepts for architectures and timing algorithms in LEO, MEO or Cis-Lunar constellations, as well as reviewing little known details of existing infrastructure, are welcome. The session is especially interested in the diverse representation of the practical or theoretical usage of GNSS timing in any field. 
Session Chairs:
Dr. John Janis, L3Harris
Calvin Lin, TL

Low-SWaP Clocks and Oscillators
Low-size, weight, and power (SWaP) clocks and oscillators are critical components for commercial and military applications. The telecom industry has moved toward tighter timing standards with power and form factor restrictions based on application. Military timing needs include communication, navigation and identification aids for soldiers, vehicles, ships, aircraft and spacecraft that require operation in extreme temperature, shock, and vibration environments. This session will discuss the state-of-the-art in low-SWaP, portable and embedded clocks and oscillators, for military, space and telecom applications.
Session Chairs:
Peter Cash, Microchip
James McKelvy, Jet Propulsion Laboratory, California Institute of Technology

Methods and Algorithms for Timing Applications and Timescales
Mathematics and statistics play important roles in clock analyses and timing applications from the classical two-sample variance to advanced filtering techniques. This session seeks contributions on mathematical developments that help to analyze clock measurements, handle data anomalies, compute statistics in the presence of missing observations, generate timescales, and/or facilitate time transfer or dissemination. Algorithms presented can support any timing-related activity from local oscillator performance to long-range timing applications. New algorithms or new applications using existing algorithms are of particular interest, including machine learning for timing applications, timescale algorithms that include optical clocks, and algorithms for timekeeping in space such as lunar timescales.
Session Chairs:
Dr. Christine Hackman, US Naval Research Laboratory
Dr. Jian Yao, UCAR/NCAR

Present and Future Space Clocks for Space Applications
Size, Weight, and Power (SWaP), reliability, vibration robustness, radiation hardening, and longevity are crucial for the space clocks. Abstracts are encouraged that consider the design, development, and performance of space clocks – presently operating, - planned for near-term operation, or - next-generation optical clocks, that are aimed at LEO, MEO, GEO, Lunar and Deep-Space missions. All types of space clocks are of interest: space-qualified crystal oscillators, warm-vapor lamp or laser pumped clocks, cold-atom clocks, ion-clocks, optical lattice clocks, and other portable clock technologies that can contribute to space-system timekeeping, aiding the ground-based navigation and other direct timing applications such as telecom, mobile and non-wired devices for military, and other scientific applications in space.
Session Chairs:
Dr. James Camparo, The Aerospace Corporation
Dr. Thejesh N. Bandi, The University of Alabama

T&F Transfer Utilizing Existing and Emerging Communication Systems
In this session we explore time and frequency transfer utilizing existing or emerging, terrestrial or space based, communication systems and networks. Submissions explore methods beyond the traditional and standardized. The topic also covers unconventional means of transferring time and frequency using naturally occurring phenomenon, non-traditional communication channels and other novel related techniques.
Session Chairs:
Dr. Nathan Barnwell, NIWC Pacific
Dr. Gustav Jonsson, RISE

Timekeeping and Quantum Networking
The goal of this session is to foster dialogue between the precision timekeeping community and technologists developing and operating quantum networks. Precise timing is a critical requirement for emerging quantum networks and related science applications. These applications exhibit a wide range of timing requirements, with some relying on post-processing for timekeeping while others necessitate stringent synchronization of photon-arrival times for advanced quantum communication tasks. We invite submissions that highlight the timing requirements of future quantum networks and other novel scientific applications. Of special interest are experimental demonstrations of timekeeping for quantum networks, timekeeping and time distribution systems using quantum information resources, and novel applications that may currently be constrained by traditional time transfer methods. We welcome contributions related to terrestrial, as well as space-based networks, with a primary focus on their timing needs. Contributions related to timekeeping for quantum communications networks as well as timekeeping for distributed quantum computers and sensors are encouraged. Synchronization concepts that address the unique challenges and opportunities of time transfer for quantum experiments are also of interest.
Session Chairs:
Dr. Ivan Burenkov, NIST
Dr. Makan Mohageg, Boeing