Precise Time and Time Interval (PTTI)

PTTI Pre-Conference Tutorials

The following pre-conference tutorials will be offered on January 21:

• Time and Frequency Transfer Over Fibre
• Frequency Combs
• Timescales and UTC Generation
• GNSS and GNSS Time Transfer
• Optical Clocks

PTTI Keynotes

"Atomic Timekeeping as a Hobby"
Tom Van Baak, Leapsecond.com

PTTI Session Topics

Advances in Next Generation Clocks
Evolving requirements and technological innovations drive the development of clocks that push the limits of performance in and out of the laboratory. Recent innovative advances in clock technologies, including novel approaches for reducing Size Weight and Power-Cost (SWaP-C), improving reliability, operability and robustness, and continuously running clocks for time-keeping. Hot and cold atom/ion(s)/molecules clocks; microwave, terahertz and optical clocks, optical frequency combs, and cavity stabilized ultra-stable lasers; cryogenic sapphire oscillators; and optically pumped clocks.
Co-chairs:
Dr. Lin Yi, Jet Propulsion Laboratory
Dr. Alexander Radnaev, NIST

Emergent Timing Infrastructure for GNSS Providers (Joint PTTI/ITM Session)
This ITM/PTTI interdisciplinary session highlights cutting-edge developments in hardware and techniques for timing on GNSS systems. Synchronization over long distances, ensemble and redundant clocks, sub-nanosecond time transfer, space-hardened clocks, optical clocks in space, space-based timescales, and novel synchronization algorithms.
Co-chairs:
Dr. James Camparo, The Aerospace Corporation
Dr. Gabriele Giorgi, German Aerospace Center (DLR), Germany

Laboratory Reports and Activities
Presentations by timing laboratories including those operated by national metrology institutes, military, and/or academic organizations. Updates describing current and future PTTI activities, including UTC(k) generation and performance, time dissemination, time services, calibrations and related research activities. Time slots in this session may be shorter (approximately 10 minutes) in keeping with historical PTTI lab report sessions allowing a greater number of labs to give oral presentations.
Co-chairs:
Victor Zhang, NIST
Francine Vannicola, Naval Research Laboratory

Poster Session
Open to all topics within the timing community. Attendees who have research that is more suitable in poster format or who prefer a poster-style delivery are encouraged to submit to this session. Please specifically choose this session to present a poster; alternate oral presentations will not automatically be assigned as posters.
Co-chairs:
Ryan Dupuis, Excelitas Technologies
Dr. Michael Coleman, Naval Research Laboratory

PTTI Applications and Techniques
Applications of precise and accurate time are ever increasing in scientific and industrial applications. The development of clocks, algorithms, techniques and/or hardware products that improves a system’s use or dissemination of precise time.
Co-chairs:
Dr. Olukayode (Kami) Okusaga, JHU/APL
Dr. John Janis, Harris Corporation

Time and Frequency Transfer Beyond GNSS
Time transfer techniques that are not GNSS oriented. Computer time transfer such as NTP, PTP, White Rabbit, Sync-E, and related systems; geostationary satellite time and frequency transfer such as TWSTFT and passive TW time and frequency transfer; and time transfer over fiber and/or free-space links.
Co-chairs:
Dr. Sven-Christian Ebenhag, RISE Research Institute of Sweden
Angela McKinley, US Naval Observatory

Time and Frequency Transfer Using GNSS and RNSS
Advances and improvements in the growing number of GNSS and RNSS systems has expanded the options for performing time transfer and changed the complexity of the analysis. Time transfer that utilizes any of the GNSS/RNSS systems including Galileo, GPS, GLONASS, QZSS, BDS and IRNSS. Multi-GNSS analysis and techniques as well as discussion of system times and references.
Co-chairs:
Dr. Joerg Hahn, ESA/ESTEC, The Netherlands
Ed Powers, The Aerospace Corporation

Timekeeping in Commercial Applications
Awareness of the importance of precise and accurate time is extending further into many applications of the civilian and commercial sector. Contributions from a wide variety of users and applications that require and utilize precise time including, but not limited to data centers, financial institutions, network security, and critical infrastructure.
Co-chairs:
Peter Cash, Microchip
Dr. Judah Levine, NIST

Timescales and Algorithms
Analysis, description and implementation of current and new time scale algorithms. Time scales based on primary/secondary frequency standards, optical frequency standards, optical cavities; the generation and steering of UTC, UTC(k) and reference GNSS time scales with increasing performance; algorithms and methods that advance the state of the art in clock data analysis and their applications; the use of Kalman filters and other robust statistical techniques; and novel processing of measurement data to reduce the measurement noise in time scales.
Co-chairs:
Dr. Stefania Romisch, NIST
Dr. Johann Furthner, German Aerospace Center (DLR), Germany

International Technical Meeting (ITM)

ITM Keynote Address

"Galileo System Status and Challenges Ahead"
Marco Falcone, European Space Agency, The Netherlands

"Ancient Chinese Time Service and Navigation Technology"
Dr. Xiaochun Lu, Chinese Academy of Sciences, China

ITM Sessions

Advanced Signal Processing for GNSS Receivers
GNSS receiver signal processing techniques for operations in challenging environments like indoor, urban canyons, foliage, scintillation or high-dynamics. Improved acquisition and tracking sensitivity, robustness and accuracy. Mitigation of multipath and NLOS signals. Weak signal processing techniques and algorithms. Use of multiple GNSS signals including new GNSS signals.
Co-chairs:
Dr. Sabrina Ugazio, Ohio University
Dr. Chun Yang, QuNav, LLC

Alternatives, Backups and Complements to GNSS
APNT, terrestrial radio-navigation, navaids and alternative PNT for aviation. Ranging and pseudo ranging technologies like DME and eLORAN, LDACS. Hybridization with other sensing technologies, like magnetometers or inertial sensors.
Co-chairs:
Dr. Maurizio Scaramuzza, Skyguide, Switzerland
Dr. Jiwon Seo, Yonsei University, South Korea

Atmospheric and Space Weather
Modeling of ionospheric and tropospheric effects on navigation. Use of GNSS in atmospheric and space weather science. Forecasting, now-casting, kriging. New application scenarios, improved models and mapping functions.
Co-chairs:
Dr. Alex Stratton, Collins Aerospace
Dr. Jun Wang, NOAA

Challenges for Unmanned Aerial Vehicles and Autonomous Systems
Advanced positioning and navigation algorithms for novel sensors, sensor fusion, and signals of opportunity. Algorithms and methods for high-performance applications using low-cost sensors. Derivation of multi-sensor system navigation performance requirements. New approaches for dealing with delayed and out-of-sequence measurements. Design of secure and trustworthy perception and navigation systems. Sensor fault detection and exclusion. Spoofing detection and mitigation. Intelligent sensor selection based on context awareness.
Co-chairs:
Dr. Mathieu Joerger, Virginia Tech
Dr. Li-Ta Hsu, The Hong Kong Polytechnic University, China

Challenges in Terrestrial and Urban Environments
Sensing, perception, and map building in ground vehicle operations. Guidance, navigation, and control (GNC) systems for autonomous or semi-autonomous ground vehicle systems. Driverless cars navigation in GNSS-denied/challenged environments. Sensing for visual interfaces of driver-assistance systems. Requirements for ground vehicle GNC systems. Validation and verification of ground vehicle GNC systems. Algorithms and tools for global path planning and local obstacle avoidance.
Co-chairs:
Dr. Andrew Hansen, DOT
Dr. Juliette Marais, IFSTTAR, France

Collaborative Navigation Methods
Developments and techniques for exploiting network connectivity to assist and improve navigation. Efforts for supplying accurate up-to-date information to fusion centers. Networked estimation. Variable latency of measurements.
Co-chairs:
Dr. Jordan Larson, University of Alabama
Dr. Jason Rife, Tufts University

Cooperation Between GNSS
Status of the various GNSS (GPS, Galileo, QZSS, BDS, GLONASS). Impact of E5/L5 signals, synergies between systems, compatibility of signals, future harmonized services, resilience, RFI monitoring and enforcement.
Co-chairs:
Dr. Todd Walter, Stanford University
Dr. Ignacio Fernández Hernández, European Commission, Belgium

DFMC Airborne Error Models
Work related to the collection, evaluation and modelling of ranging errors experienced by an airborne receiver. Relevant topics include data collection campaigns, airborne antenna and receiver hardware, installation characteristics, data collection, analysis techniques, data sorting and clustering, modelling techniques including statistical topics, separation of error sources and subsequent model building for use in future DFMC airborne applications.
Co-chairs:
Matteo Sgammini, European Commission, Italy
Markus Rippl, German Aerospace Center (DLR), Germany

Emergent Timing Infrastructure for GNSS Providers (Joint PTTI/ITM Session)
This ITM/PTTI interdisciplinary session highlights cutting-edge developments in hardware and techniques for timing on GNSS systems. Synchronization over long distances, ensemble and redundant clocks, sub-nanosecond time transfer, space-hardened clocks, optical clocks in space, space-based timescales, and novel synchronization algorithms.
Co-chairs:
Dr. James Camparo, The Aerospace Corporation
Dr. Gabriele Giorgi, German Aerospace Center (DLR), Germany

Geodetic Techniques and Applications
Long observation times, long processing times, detection of milimetric deviations, networks of geodetic observing stations. Use of new GNSS hardware - antennas and receivers. Novel applications.
Co-chairs:
Dr. Sunil Bisnath, York University, Canada
Dr. Jihye Park, Oregon State University

GNSS and Security: Jamming and Spoofing
Making GNSS more robust, through signal processing, complementary PNT or other means. Applications in robust positioning, secure time transfer. Threat modeling, assessment and mitigation. Integrity implications of security measures.
Co-chairs:
Dr. Chris Hegarty, The MITRE Corporation
Dr. Fabio Dovis, Politecnico di Torino, Italy

GNSS for Aviation: Integrity and Augmentation
Receiver-based integrity, integrity in Ground-Based and Satellite-Based Augmentation Systems, challenges in the provision of integrity in multi-frequency / multi-constellation services and high accuracy GNSS.
Co-chairs:
Deborah Lawrence, Federal Aviation Administration
Dr. Juan Blanch, Stanford University

High-Performance GNSS Receivers
Adaptive, innovative and intelligent tracking loops. Alternative tracking algorithms. Exploitation of new signals in the tracking loop. Coupling of different signal tracking loops. Modeling of disruptions (RFI, ionospheric scintillations, multipath, etc.) for advanced tracking loops. Resilience to disruptions with new acquisitions and tracking algorithms. Signal acquisition and tracking in adverse operational environments.
Co-chairs:
Friedrike Fohlmeister, German Aerospace Center (DLR), Germany
Dr. Sai Kalyanaraman, Collins Aerospace

Image-Based Navigation
Systems and advanced algorithms related to emerging vision-based navigation applications in GNSS-challenged environments. Integration of data from multiple sensors for combined situational awareness and navigation. Vision sensor modeling, calibration, data processing and image feature extraction. Feasibility analysis and challenges of vision-based navigation. Integrity, availability and continuity aspects of vision-based navigation methods.
Co-chairs:
Dr. Clark Taylor, Air Force Institute of Technology
Dr. Maarten Uijt de Haag, TU Berlin, Germany

Inertial Measurements
Algorithms and systems for multi-sensor or aided inertial navigation. EO/IR, LIDAR, GNSS and RF aided inertial navigation systems. Fault detection and isolation in integrated inertial navigation systems.
Co-chairs:
Dr. Andrey Soloviev, QuNav
Dr. Zhen Zhu, East Carolina University

Integrated Navigation Systems
Fusion of measurements from multiple sensors, data and information sources. Algorithms, test methods, and results of new implementations integrating diverse sensors such as GNSS, inertial sensors, odometers, magnetometers, radar, LiDAR, cameras, barometers, maps, signals of opportunity, infrared, ultrasound sensors, etc. Novel architectures that incorporate developments in low-cost or quantum sensing, distributed collaborative approaches and systems that integrate environmentally sensed data or other data held in spatial databases are encouraged.
Co-chairs:
Jamal Atman, Karlsruhe Institute of Technology, Germany
Dr. Allison Kealy, RMIT University, Australia

ITM/PTTI PLENARY SESSION

Chair:

Maritime Applications
New concepts, advances, and algorithms related to surface and underwater navigation. Use of inertial navigation for underwater vehicle navigation. Advances in acoustic devices for bathymetry, position location, and velocity measurement and their application to maritime vehicles. Development and application of new sonar elements. Transponder localization and SLAM-type approaches for surface and underwater vehicle navigation.
Co-chairs:
Stig-Erik Christiansen, Kongsberg Seatex AS, Norway
Dr. John Scott Parker, Draper

Navigation of Satellites and Spacecraft
Navigation services using LEO satellite constellations. GNSS navigation beyond MEO. Technical advances of both COTS and specialized systems for space applications. Topics in constellation navigation, attitude determination, and formation flying. GNSS Earth observation techniques. Tropospheric and ionospheric sounding by radio occultations with new and legacy GNSS systems and signals. DME/TACAN interference with RO measurements. Reflectometry for environmental remote sensing of land, ocean and ice. Synthetic-Aperture Radar.
Co-chairs:
Dr. André Hauschild, German Aerospace Center (DLR), Germany
John Langer, The Aerospace Corporation

New Challenges in GNSS
Pushing the limits of GNSS. Assessing performance of current systems and predicting the performance of future ones. GNSS evolution, modernization, new applications and niche markets. Innovative combination of GNSS with sensors and augmentation systems. Challenging environments: low SNR, highdynamics and low power consumption.
Co-chairs:
Dr. Takeyasu Sakai, ENRI, Japan
Dr. Terry Moore, University of Nottingham, UK

Pedestrian and Indoor Localization
Positioning methods for indoor and GPS-challenged environments, including fingerprinting, fine timing measurement, SLAM, inertial modelling, sensor fusion, machine learning, deep learning and estimation process. Multiple sensing modalities including inertial sensing, magnetic fields, opportunistic radio sources, sound, laser, Infrared (IR) and others, are all in scope.
Co-chairs:
Dr. Liang Chen, Wuhan University, China
Dr. Ramsey Faragher, Focal Point Navigation, UK

Precise GNSS Positioning
New algorithms and methods for improving Precise Point Positioning (PPP), Real-Time Kinematic (RTK) and other precise positioning techniques (e.g., PPP-RTK, network-RTK). Multi-constellation solutions using single-/multi-frequency high-cost and low-cost receivers/antennas, including smartphones. PPP with Integer Ambiguity Resolution (IAR). Stochastic and dynamic modelling for single- and multi-epoch solutions, respectively, and its effect on the positioning performance. Methods and algorithms for reliable outlier detection, such as cycle-slips. Estimation of corrections relevant for PPP-RTK (or PPP-IAR) such as fractional phase biases, satellite orbits and clocks, atmospheric delays and differential code biases. Interoperability of correction services with different user equipment.
Co-chairs:
Dr. Adria Rovira-Garcia, Universitat Politecnica Catalunya, Spain
Dr. Robert Odolinski, University of Otago, New Zealand

Receiver Design and Sensor Fusion for Mass Market Applications
Multi-band GNSS receiver design and sensor fusion algorithms for high-precision navigation solutions targeting low-cost and low power mass-market applications. Modeling, augmentation (services, sensors) and evaluation of demanding commercial applications.
Co-chairs:
Dr. Alexander Somieski, u-blox AG, Switzerland
Dr. Mohamed Youssef, Royal Military College of Canada