United Kingdom

The poster will present a new approach to teaching location estimation techniques, including GNSS. The new approach assumes relatively little (undergraduate-level familiarity with linear algebra, calculus, and a bit of continuous probability) and is therefore accessible to undergraduate students in math, computer science, physics, and engineering. Most existing approaches assume a lot more (e.g., extensive background in statistical signal processing) and are therefore accessible to much narrower groups of students. The material, along with problems (many solved) and small programming exercises, is available as a book (Location Estimation from the Ground Up, Sivan Toledo, SIAM 2020). 

The material covers a wide range of techniques and ideas, starting from linear least squares, probabilistic justifications for least-squares (maximum likelihood), non-linear least squares, time-of-arrival location estimation and GNSS, signal processing for arrival-time estimation (code phases in GNSS), Kalman filtering, and integer least squares (carrier-phase GNSS observations and RTK). The material also covers important topics like error analysis (Cramer-Rao bounds, estimation of error covariance matrices, and DOP).

The presentation is consistent and thorough. Most algorithms are fully explained, in the sense that they can be implemented by the students (QR factorization, FFT, Kalman filtering, and algorithms for integer least squares). A few algorithms are explained at a higher level, to allow students to understand their behavior but without low-level details (nonlinear optimization and the SVD).

The poster will present the approach and will encourage discussion of how courses in this area are structured and how to widen their target audience.

Navigation 2021

Location Estimation from the Ground Up: A New Teaching Approach

### Welcome to Navigation 2021!

Our aim was to bring diverse disciplines together to stimulate insights and knowledge sharing towards a more navigable world. We hope we achieved this!

Navigation and timing are critical to the world we all inhabit. We believe that the work of the wider navigation community enables societal benefit including support to national grand challenges and also the United Nations’ Sustainable Development Goals. To achieve this requires collaboration and understanding across science, technology and practice.

Navigation 2021 is about much more than technology innovation, it also showcases science and research from across the wider community, including animal navigation, cognition and human factors.


Our aim was to bring diverse disciplines together to stimulate insights and knowledge sharing towards a more navigable world. We hope we achieved this!

lightning talk

Session 1.1.

The ontogeny of cognitive maps in the real world

A framework for Assured PNT

GNSS benefitting society

Position, Navigation and Timing (PNT) is integral to the safety, security and prosperity of the United Kingdom, its Overseas Territories, and wider global interests. PNT is also critical to the UK’s national security supporting command, control, and communications capabilities, and to the cyber enterprise. The loss of PNT services from modalities such as Global Navigation Satellite Systems (GNSS) (like the US Global Positioning System (GPS)) will have a significant impact on our economic wellbeing. This paper describes the development of a framework for the coordination of PNT across the UK Government and for the wider UK. It proposes both a strategic and integrated system-of-system architecture that addresses how to bring the complex area of policy, strategy, skills, legislation, delivery mechanisms and multiple technologies, including research and development, together in a coherent way, integrating existing programmes, as well as proposes how to determine appropriate technology approaches looking to the future. It is the core outcome of an evidence based comprehensive review and PNT Strategy development in the UK with the goal to ensure PNT users have access to resilient and assured PNT services when they need them.

Developing a Strategic Architecture Framework for PNT in the United Kingdon

GNSS Signal Quality Monitoring via GNSS-Finland Service

Introducing GEONAV IoT, an innovative positioning solution for both indoor and outdoor applications such as Elite sport, assets and autonomous drone tracking.

In 2018 and 2019, Thales developed GEONAV IoT solution in the frame of European Space Agency program. GEONAV IoT is a precise positioning solution based on GNSS advanced algorithms for outdoor positioning and UWB technology for indoor positioning. Positioning information computed by an embedded device is sent to a dedicated monitoring web application. In this project, the solution has been tested for both Elite sport and Valuable Asset management applications.

Since December 2019, Thales entered a European program, to collaborate with European partners to maximise the solutions potential: Hertz Systems, ChipCraft, Drone Consultants Ireland and Telespazio France. The consortium currently coordinates on three axes: technological solution enhancement, autonomous drone applications and to create a European chain for GEONAV IoT industrialization.

In this context, GEONAV IoT solution is enhanced by integrating multi-constellation and dual-frequency GNSS chip and algorithms. Moreover, the solution is 5G ready: the 5G ready communication module enables the broadcasting of ephemeris and corrections from a GEONAV IoT base station to the user terminal. 5G also enables the sending of secured positioning information from the terminal to the monitoring web application. These enhancements of the solution aim to improve the global performance, specifically the accuracy, continuity and Time To First Fix. Hybridization between 5G and GNSS is also studied in this project. 

As the Unmanned Aerial Vehicle market expands, GEONAV IoT aims at providing a reliable position as part of the inner drone navigation system but also a monitoring application specifically designed to meet the drone operator’s needs. Tests in real conditions will demonstrate the benefits of GEONAV IoT solution in providing reliable positioning data to the drones in order to improve safety and location reliability.

GEONAV IoT - A precise positioning solution for indoor and outdoor environments using GNSS, UWB and 5G technologies.

Do people get lost inside your building is an important question for many organisations with large scale multi level buildings to ask. Most will find it challenging to evidence their response unless they have had waylosing occurrence with negative consequences. This paper will present findings from a 5 year doctoral study exploring recalled and real-time causes and wayfinding strategies following waylosing inside buildings and will present a new theory - the MAGPIE Matrix - that could help designers, architects, engineers and scientists design buildings that are more navigable with indoor wayguiding systems that are people-centred and inclusive.

Indoor Navigation & Waylosing: Can the MAGPIE Matrix help create a more navigable world?

A method is presented to synchronize and aid the absolute navigation solutions of the members of a swarm by means of relative inter-swarm measurements. Moreover, the operational benefits thereof are discussed.

Collaborative operation of vehicles, especially of unmanned aerial vehicles in close formation, requires accurate relative and absolute navigation. A novel method for collaborative multi-sensors fusion of relative and absolute navigation information is presented designed to cope with GNSS-denied environment.

Relative inter-swarm measurements and absolute navigation means cannot be fused straight away as they are defined in fundamental different frames. Moreover, the sensor fusion has to fulfill two objectives – firstly, restoring the relative geometry of the swarm, and secondly, determining the absolute positions of each vehicle in an optimal way for the overall swarm.

Key for collaborative navigation is to establish a common knowledge within the swarm which is achieved by exchanging the absolute state estimations, the state uncertainties and the relative measurements. Based on the common knowledge the “Consistent INS Drift Algorithm” computes for each vehicle a new position which is statistically optimal for the overall swarm. Simultaneously, these new positions represent the actual geometry of the swarm by essentially resampling the relative measurements. By fusing these new positions the navigation filters are synchronized and the relative measurements are implicitly used to aid the absolute navigation solutions.

This reveals several operational benefits: the absolute navigation solutions are consistent – the whole swarm drifts consistently as only the Inertial Navigation Systems (INS) may remain as absolute navigation means, and hence, the naming “Consistent INS Drift Algorithm”. Moreover, the drift is statistically slower than the best individual INS. Having at least one vehicle equipped with a drift-free navigation mean such as Terrain Referenced Navigation stops the swarm to drift. Therefore, heterogeneous navigation systems are natively supported enabling true collaboration.

Collaborative Navigation - Synchronizing and Aiding the Absolute Navigation of Swarm Members using Relative Inter-swarm Navigation Information

Galileo is currently testing its Open Service Navigation Message Authentication (OSNMA). OSNMA is based on authenticating the navigation data with cryptographic features, assuring the origin of the data. However, OSNMA does not explicitly authenticate the GNSS signals, and signal authentication is necessary to protect the signal time of arrival. Otherwise, an adversary can replay the signals and alter the time of arrival, spoofing the position even if the data used to calculate it is authentic.

This work describes a method for protection against signal replay attacks based on Galileo OSNMA and analyses its feasibility in smartphones.

The OSNMA protocol is based on the transmission of message authentication codes and the later disclosure of a cryptographic key used to generate them. Once the key is authenticated, the receiver authenticates the navigation data with the codes and the key, obtaining a data-authenticated position.

As in most cryptographic systems, the authentication codes are unpredictable. This feature makes the Galileo signal unpredictable as well. Our method is based on leveraging this signal unpredictability in combination with assistance information, to protect against signal replays.

The method has been tested in smartphones (Samsung S10 and Xiaomi Mi8) using Android, which provides the GNSS raw measurements and bitstreams. While the Galileo E1-B bitstreams are provided only intermittently, the complete authentication process is performed in less than ten seconds for the first satellite and the total time for authenticating four or more satellites is less than two minutes.

The results show that, while signal antireplay is not the primary purpose of OSNMA, bit unpredictability combined with accurate time synchronization can be exploited to make spoofing more difficult.

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Location Estimation from the Ground Up: A New Teaching Approach

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