Search and Rescue support via Phased Array Antenna
Improving accuracy of distress signal positioning
Phased Array Antenna for Search and Rescue (PAASAR) will be an essential part of Medium Earth Orbit Local User Terminals (MEOLUTs), improving the accuracy of distress signal positioning. The accuracy of a MEOLUT system is dependent on the number of satellites that can be tracked simultaneously. PAASAR will allow for the simultaneous reception of all distress signals relayed by all Galileo and GLONASS satellites in view. Conventional MEOLUT systems are restricted to 4 steerable dish antennas, each tracking a single satellite.
The goal is to create a Phased Array Antenna Monitoring Facility to replace the need for traditional MEOLUT facilities requiring multiple tracking dish antennas for reception of Search And Rescue signals from multiple spacecraft.
The prime objectives of the PAASAR project achieved:
- Implement a prototype Phased Array Antenna consisting of 50 antenna elements
- Achieve beam forming to at least 4 satellites, and more if available
- Acquire Search And Rescue / Galileo signal from those satellites
- Verification and Validation of the prototype system
- MEOLUT design and Business Case development
The principal benefits in the PAASAR approach are:
- Technical: maximising the number of tracked satellites from a MEOLUT (practically all in view);
- Technical: processing many satellites on one location, i.e. working with TDOA (Time Difference of Arrival) rather than TOA and avoiding the uncertainties linked with TOA determination and sharing;
- Technical: minimising re-pointing (satellite hand-over) time, which is a major issue with dishes, considering high availability requirements;
- Reliability: Reliable antenna infrastructure;
- Logistics: one 2[-3] m dome replaces up to 12 tracking dishes; Has a small physical footprint;
- Industrial policy: gives European industry a competitive edge in this niche market;
- Spin off: this kind of array, owing to high degree of central-symmetry, could potentially prove to be useful for other applications.
How it works
The PAASAR Proof of Concept (POC) system is a single, compact phased array composed of 50 small antennas that are combined in the digital domain to multiple independent beams. PAASAR provides better performance because it has no limitation on the number of satellites that can be tracked simultaneously. It also has a smaller footprint, no re-pointing time, less maintenance costs, provides a reliable antenna infrastructure, and calibrates itself independently.
PAASAR acts as multiple MEOLUT sites in one, eliminating inter-site interference and scheduling issues; thereby removing the risk that critical signals are lost. PAASAR also reduces the running cost of a MEOSAR system.
The Phased Array Antenna technology has a multitude of application areas to replace conventional antenna systems and architectures given its superior performance and lower cost. The need for high performance phased arrays for large sky coverage monitoring of RF emitting entities (eg. spacecraft) is evident.
The following different types of customers are evident:
· MEOLUT and LEOLUT operators
· Cospas-Sarsat member states that do not yet operate a GEOLUT or MEOLUT
· Phased Array Technology (antenna) procurement entities
· Defense & Security entities
· Monitoring & Telecomunications operators