070 - Advanced MEOSAR Test Beacon Setup
The location methods used in the MEOSAR systems are sensitive to beacon motion. A lot of work has been undertaken during the past years to elaborate test means in order to evaluate the MEOSAR location performance with moving beacons (use of vehicles, drones, turn-style mechanism, beacons of opportunity). The test means used have several drawbacks: limited test time, limited speed range, reliability and/or transportability. With this activity it is planned to develop a solution based on a Digital Beam Forming Network (DBFN) antenna that would be a static system able to emulate any kind of beacon motion (by transmitting signals with different frequency/delay in each satellite direction). Such a system could be used for testing and/or commissioning of existing or future Cospas/Sarsat MEOSAR services.
The test beacon setup will work as a classical one with the possibility to program test scenario including: transmission time, message content, transmitted power, transmitted frequency, waveforms parameters, etc.
As this system will not contain mechanical parts, its maintenance will be easier and cheaper than mechanical systems. It will open the door to the introduction of moving reference beacons for monitoring the quality of MEOSAR services: the system could be used continuously to check the location performance of test beacons with various range of motions.
The objectives of the proposed activity are to develop an Advanced MEOSAR Test Beacon Setup consisting of DBFN (Digital Beam Forming Network) antenna system and the supporting SW, for MEOSAR testing and performance evaluation, in particular in slow-moving and fast-moving cases and cases with local attenuation and masking.
The tasks to be performed will include:
- design and development of the DBFN antenna, which will manage several links in parallel (one link per satellite). From the scenario defined by the user (which includes a position and motion to be simulated), the supporting SW will calculate for each satellite the shift in transmit frequency (to emulate different Doppler), in transmit time (for different time of arrival – TOA) and in power (for local masks and attenuation, which may be useful to evaluate the performance in canyons or mountainous areas). At the antenna level, the phase law will be defined with respect to the satellite positions;
- design and development of the related calibration system, that will be associated to the DBFN antenna in order to check that the signals are transmitted in the correct direction.
The main outputs of the activity will consist of:
- demonstrator of the Advanced MEOSAR Test Beacon Setup and associated calibration equipment;
- associated documentation.