Timing has become a critical resource for various public and defense infrastructure. GNSS systems have been the defacto standard for providing timing service for these infrastructure. Various studies have concluded that GNSS system can be spoofed; hence a need to have multiple systems providing timing information to maintain the resilience. NextNav has developed a TerraPoiNT system, a terrestrial-based positioning, navigation and timing system which can complement existing systems as well as serve as a backup to the GNSS. TerraPoiNT system (a.k.a Metropolitan Beacon System), a type of Terrestrial-Beacon system, is a Time-Of-Arrival multilateration system offering 3D positioning and timing through a dedicated network of synchronized transmitters using Code Division Multiple Access spread spectrum signals. TerraPoiNT beacons can synchronize between themselves without the need for an absolute time source like GNSS, thus proving to be an ideal alternative to the GPS system. Beacons have a timing estimation sub-system which has access to one or more stable time sources like a precise atomic clock (such as Cesium/Rb) allowing long holdover time to be maintained. Each beacon can listen to multiple beacons adding resiliency into the network. This self-synchronization capability is scalable to a large network with only a few beacons requiring absolute time source or atomic clocks due to multi-hop beacon time transfer capability. TerraPoiNT System capabilities were assessed by the U.S. Department of Transportation at NASA-LaRC as part of the alternate navigation technology assessment for positioning, navigation and timing. TerraPoiNT timing accuracy in static indoor test over 72-hours was within 25 ns (95%) and within 30 ns (95%) in a basement location indicating an accurate and robust performance in a challenging locations as well as long-term stability. TerraPoiNT system demonstrated accurate, reliable and robust performance and it was rated #1 among all the technologies evaluated in position and timing trials

TerraPoiNT: An Advanced Terrestrial Timing System

NextNav has developed a TerraPoiNT system, a terrestrial-based positioning, navigation and timing system which can complement navigation systems as well as serve as GNSS-backup. TerraPoiNT is a Time-Of-Arrival (TOA) multilateration system offering 3D positioning and timing through a dedicated terrestrial network of synchronized transmitters using Code Division Multiple Access spread spectrum signals like GPS. TerraPoiNT transmitters can synchronize between themselves without the need for an absolute time source like GNSS, thus proving to be an ideal alternative to the GPS. TerraPoiNT offers vertical positioning through integration with barometric and environmental reference information provided over the data payload. The beacons are designed to detect anomalies in position and timing. This capability enables TerraPoiNT to detect local anomalies in any absolute time system like GPS. TerraPoiNT’s innovative methods to address the near-far reception problem coupled with the short multipath resolution capability enables it to provide a robust performance in any environment. TerraPoiNT signals can penetrate inside the building enabling TerraPoiNT receivers to conquer the frontier of indoor positioning. TerraPoiNT System capabilities were assessed by the U.S. Department of Transportation at LaRC as part of the alternate navigation technology assessment for positioning and navigation under various scenarios including car and drone navigation. TerraPoiNT technology showed exemplary performance in all the tests under different dynamics. The results from the vehicle navigation test provide accuracy within 3m (50%) and 8m (95%). TerraPoiNT receiver utilized fusion of TerraPoiNT signals integrated with inertial sensors in these 2D navigation tests. Drone navigation test results are within 3D performance < 3m (50%) and < 5m (95%). In these drone tests, TerraPoiNT receiver utilized only the TerraPoiNT signals without any inertial sensor fusion. TerraPoiNT system demonstrated accurate, reliable and robust performance in entire trials and it was rated #1 among all the technologies evaluated both in position and navigation trials

TerraPoiNT: An APNT system to augment and enhance urban/Indoor navigation

***Session Chair: Prof Heidi Kuusniemi*** 
***Session Co-Chair: Andrew Richardson***

Session 1.5.

technical paper

### 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.


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!

***Session Chair: Dr Alan Grant*** 
***Session Co-Chair: David Pollitt***

**TerraPoiNT: An APNT system to augment and enhance urban/Indoor navigation**
 Sameet Deshpande (Presenting) (nextnav, Calgary, Canada)
 Arun Raghupathy (nextnav, Bangalore, India)

**The Galileo SAR Two-Way Communication Service : presentation of the future service and end-to-end demonstration preparation.**
 Sylvain Delattre (Presenting) (CNES, Toulouse, France)
 Antonio Rolla (European Commission, Brussels, Belgium)
 Sylvain Delattre (CNES, Toulouse, France)
 Laurent Arzel (Telespazio, Toulouse, France)
 Kevin Salsac (Thales France, Toulouse, France)
 Josep Montolio (PILDO, Barcelona, Spain)
 Alain Bouhet (Orolia, Guidel, France)


**On the Positioning Performance of VDES R-Mode**
 Markus Wirsing (Presenting) (German Aerospace Center, Weßling, Germany)
 Dr. Ronald Raulefs (German Aerospace Center, Weßling, Germany)
 Armin Dammann (German Aerospace Center, Weßling, Germany)

**Integration of Shadow Matching with Road Information for Improved Mobile Urban Positioning**
 Dr. Han Gao (Presenting) (Riemann Lab, Huawei Technologies, Shenzhen, China)

**Session Posters**
* **Hiromune Namie** "Impact of mobile phone radio waves on the cm-Level Augmentation Service provided by the Quasi-Zenith Satellite System in Japan"

* **Fabian Ruwisch** "Analysis of the Carrier Phase Multipath Error in the Context of Correction Maps for Urban Navigation"

* **Sivan Toldeo** "Location Estimation from the Ground Up: A New Teaching Approach"

Sameet Deshpande

2

SHORT BIO

Presentations

TerraPoiNT: An Advanced Terrestrial Timing System

TerraPoiNT: An APNT system to augment and enhance urban/Indoor navigation

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