The Critical Link

Recently in The Critical Link we detailed how Telesat Lightspeed will deliver several capabilities that governments require from their secure dedicated military systems. Some of these features have become critical requirements for commercial customers and were designed into Telesat Lightspeed as key functionality.

Others – such as the number of satellites in orbit, the satellites in constant movement with ground terminals handing off one to the next – result from the Low-Earth-Orbit (LEO) system architecture. Finally, additional optional security features can be added to Telesat Lightspeed services to satisfy the most stringent government requirements.

New levels of protection

Telesat Lightspeed can provide customers with Low Probability of Intercept (LPI) and Low Probability of Detection (LPD), which is highly effective at limiting an adversary’s ability to intercept or detect user terminal transmissions. The narrow diameter transmit beams on the satellites limit an adversary’s ability to determine a user terminal location by monitoring satellite transmissions.

Narrow transmit beams on the user terminals (approximately 2 deg for a 60 cm antenna) make it extremely difficult for an adversary to detect terminal transmissions. In addition, Telesat Lightspeed satellite beams hop from cell to cell with a dwell time as short as 730 microseconds. Power control, adaptive carrier bandwidth, and adaptive coding and modulation can adjust the waveform to increase bandwidth and minimize power to make the signal even more difficult to detect. With satellite phased array antennas, adaptive carrier bandwidth, coding and modulation, and a constellation with multiple satellites always in view, Telesat Lightspeed will protect against unintentional interference and a level of malicious jamming.

The satellite’s receive arrays remain linear over a wide dynamic range and are well protected against high levels of RF interference. If fading or interference is detected, the network’s adaptive carrier bandwidth, coding and modulation feedback loop will increase user terminal power and adjust carrier bandwidth, coding and modulation to more robust operating points to maintain connectivity. The Telesat Lightspeed constellation will provide significantly more protection against jamming and interference than most LEO satellite networks.

Specialized Protection

For sensitive government missions, Telesat can also offer user terminal location obfuscation on the Telesat Lightspeed network. In this offering, terminals on the network do not need to transmit their exact location to the satellites. The Aalyria Spacetime software we use for system orchestration partitions the earth into thousands of cells, each with a corresponding number. Government terminals can use GPS or other means, plus a Telesat Lightspeed cell map, to determine their cell number. Each government terminal’s cell number is AES-256 encrypted, transmitted up to a satellite overhead, and routed to the orchestration software.

Since the Spacetime software does not know the terminal’s exact location, it must assign beams that cover the entire cell. Using the terminal’s cell number rather than GPS position obfuscates the government terminal’s location to an area of uncertainty of approximately 6,000 square kilometers. Neither the system orchestration nor a potential adversary who somehow intercepts and decrypts the terminal location data knows the exact terminal location.

As governments increasingly look towards purchasing SATCOM-as-a-Service rather than building their own satellite networks, Telesat stands ready to provide a compelling value proposition with resilient, secure, and assured connectivity.