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Connecting LEO and GEO Satellites with Inter-satellite Data Relay System (IDRS)

While there is no shortage of challenges for satellites, especially the low earth orbit or LEO satellites, one of the tricky ones is to to ensure some kind of continuous connectivity to a ground station. LEO satellites orbit the earth roughly every 90 minutes and are in contact with their ground station for roughly 4% of the orbit. To have a continuous connectivity available on demand, Inmarsat and Addvalue Innovation announce real-time link between satellites with promise of quicker delivery of data and imagery across the globe.


The press release says:

The world’s first ever publicly-available, real-time link between satellites in high and low earth orbits is now available, it was announced today. After a five-year collaboration, Inmarsat and Addvalue Innovation are pleased to announce the Commercial Service Introduction (CSI) of their Inter-satellite Data Relay System (IDRS) service, following the successful demonstration of the first live data connectivity between customer Capella Space’s Control Center and its recently launched Sequoia satellite at low earth orbit.

This success paves the way for satellites in low earth orbits to continuously maintain communications with the ground, receiving and transmitting data on demand and in real-time. Satellites in lower orbits typically include those used for climate observations and disaster relief efforts, as well as a host of other applications. Traditionally, these satellites have had to wait until they came back into range of a ground station before being able to receive tasking information and transmit telemetry and valuable collected data. The new data link should reduce waiting times for such data transfers from several hours to a handful of minutes. This can enhance life-saving efforts in a natural disaster or enable observers to spot issues and direct resources to tackle them before they develop or get out of hand.


Picture source

The new on-demand IDRS service was successfully commissioned on Capella Space’s Sequoia satellite at 10:14am PST on November 12th 2020. The Capella satellite, situated in low earth orbit, communicated with Inmarsat’s I-4 satellite network, which operates at the L-band spectrum and sits in a high earth, geostationary orbit. Capella Space is a market leader by being the first LEO satellite operator to leverage this enhanced functionality to offer an unprecedented level of responsiveness to its customers.

While instantaneous connectivity on the ground is commonplace, LEO satellite operators have traditionally suffered from high latency in making contact with their satellites, due to geographic sparsity of the required ground stations. This new system, consisting of the Addvalue on-board terminal and the Inmarsat data relay service, achieves a world first by allowing persistent, on-demand transfer of data, creating a new paradigm for smallsat LEO operations.

The benefits of Addvalue and Inmarsat’s solution go beyond the speed at which subscribers receive their data and images. Satellite operators also gain significant operational efficiencies by being able to stay in constant contact and control of their constellation. This is especially pertinent in the fast growing new space industry of large satellite constellations when real time control and coordination of multiple satellites can effortlessly and simultaneously be accomplished through the use of IDRS. This stands in contrast to current practice with its demanding need to coordinate and precisely time communications with multiple ground station operators.

This video explains the concept in detail

IDRS brochure is available here.

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