The scope of the work is to implement a multichannel disciplined oscillator which will optimally combine a set of independent information (GNSS, ADS-B, PTP/NTP) in order to provide Time and Frequency with the highest level of protection against GNSS attacks. In fact, the proposed system will implement a set of countermeasures able to detect and to resist to spoofing, meaconing and even jamming attacks involving the MODO Timing unit. Two versions of the MODO unit will be studied and implemented, as follows:

• Multichannel OCXO Disciplined Oscillator: A COTS based version which is relying on commercial OCXO oscillators. The OCXO are used also to implement a MODO prototype, able to support algorithms consolidation and testing prior to the availability of the optical oscillator
• Multichannel Optical Disciplined Oscillator: An innovative and much more resilient Optical oscillator, which will be able to provide very accurate timing signals, even following a severe jamming and/or spoofing attack lasting one day