Satellite Search and Rescue enabled by Multi-Layer PNT

Last Updated: 14/03/2023 11:59     Created at: 14/03/2023 11:56

Final Presentation of NAVISP Project EL1 045 now available:

On Wednesday, March 08, 2023, Stratos Solution presented, together with its consortium partners M3 Systems Belgium SPRL and  Sonaca S.A, the results of the NAVISP project “Multi-Layer PNT for SAR (HASARDS)”. About 40 people from industry and research institutes followed the interesting presentation and the subsequent interactive Q&A session.

Satellite Search and Rescue (SAR) instruments are currently flying on board MEO satellites in several GNSS constellations. These platforms complement the existing LEOSAR and GEOSAR satellites. However, existing LEO/GEOSAR are slow in detecting active beacons due to several limitations in the design (limited satellites, fast orbits, no independent location capability, etc.). MEOSAR, on the other side, exceeds the individual advantages of each of the other options, but they are not perfect either, e.g., accuracy is still in the order of km and localisation of fast-moving beacons is not possible.

After the incident in March 2014 when the Malaysian Airlines MH370 flight disappeared from radar screens leaving very little information about its location, the International Civil Aviation Organization (ICAO) requested COSPAS-SARSAT, which sets and oversees SAR standards, to work on SAR capabilities, particularly on the context of flight tracking during a distress event.

Combining High Altitude Pseudo Satellites (HAPS) with multi-layer LEO/MEO/GEOSAR ranging could be a solution to improve beacon localisation. HAPS can also be quickly moved over a specific location within the designated service area. Another HAPS benefit is the improved link budget, between 30 and 40 dB, depending on its altitude. Furthermore, TOA/FOA measurements with considerably increased SNR are expected to improve the independent localisation of distress beacons in challenging environments. The HAPS could also bring additional features to the SAR system such as augmented reality (e.g. real-time imaging superimposed with localization), shorter transmission path (e.g. signal directly redirected to rescue teams below), and direct georeferencing by visual means.

The objective of this project was therefore to investigate the added value that HAPS could bring to SAR in terms of local augmentation, through a feasibility study and demonstration using simulations and field experiments. Moreover, the project addressed whether proposed enhancements could be either done by integrating the already existing beacon-MEOSAR link as an additional collaborating layer or acting as a standalone (and new) member of the COSPAS-SARSAT system. This was accomplished through a three-step process that included analysis of operational use cases and requirements, system analysis including functional and performance requirements, and validation through flight tests and simulations to evaluate objectives and acceptance criteria.

At the end of the project, the most plausible identified scenario consists of regional HAPS layers designed and built to interact directly with Rescue Coordination Centres (RCC) rather than the COSPAS-SARSAT system. RCC could make use of the independent data products provided by the HAPS layer together with the traditional COSPAS-SARSAT services.

Thanks to the support of NAVISP, an architecture and set of features is suggested to be embarked on a layer of HAPS deployed for the purpose of augmenting the search and rescue efforts in areas of interest. In the future, this could complement existing surveillance by expanding coverage and adding redundancy, enabling ad hoc communications between the rescue team and the person in distress, and providing real-time video images of the area in question, which should be useful for planning and coordinating rescue efforts.


The project was carried out in the scope of NAVISP Element 1, which is dedicated to technology innovation of the European industry in the wider PNT sector.

More detailed information can be found in the slides of the Final Presentation.