The recent growth of consumer satellite communications, like Starlink from SpaceX, has brought greater connectivity to remote locations. Many mission critical organizations rely on Land Mobile Radio for this coverage – so will Satellite comms make LMR redundant?
The first satellite to relay voice communications was launched by the U.S in 1958. As of May 2022, there are currently 5,465 active satellites in various earth orbits, serving a variety of purposes ranging from voice communications to high speed-low latency broadband around the world.
Starlink is the world’s first and largest satellite constellation using LEO (low-earth-orbit) to deliver high-speed and low-latency broadband to internet users all over the world. There are many satellites parked in earth’s orbit for similar purposes:
Communications satellites orbit above the Earth, receiving radio signals transmitted from a ground station which has a parabolic dish antenna aimed at it. The satellite amplifies the signals and re-transmits them to be received by the appropriate party back on Earth. Communications satellites can be parked in various types of orbits. Typically they are launched into geosynchronous (GEO) orbit which follows a high-altitude path of 22,236 miles (35,786 kilometers) with a speed matching the earth’s rate of rotation to remain synchronized.
Differences between LMR and Satellite
Satellites use higher frequencies that are more powerful than radio waves, this helps reduce bandwidth consumption, leaving more bandwidth to send more communications, compared to its LMR predecessor. Satellite communications are effective in their own right but harbor plenty of expenses such as bandwidth costs compared to a low-cost but effective option such as LMR. With the rapid expansion of satellite communications, there is also a growing problem of interference between adjacent satellites in an increasingly crowded sky.
Critical service agencies often choose not to rely on commercial broadband orientated connections, due to outages and traffic created by other non-critical users on the network. To address this issue, future redundancy or alternative terrestrial communications infrastructure must be built to ensure communications are always available.
Satellites are almost never owned by the organization using it to communicate, they are licensed from a private vendor, who can decide to manage which traffic takes priority on a network; with other downsides being a shared connection with other consumers, your emergency calls sharing bandwidth with streaming services like Netflix, and other bandwidth hungry platforms. Satellites also suffer from reduced availability during high cloud cover and adverse weather conditions; when critical comms are often needed the most.
Alongside Satellite and LMR, Public Safety broadband networks are emerging around the world, such as FirstNet in the US, and New Zealand’s PSN (Public Safety Network) upgrade with Next Generation Critical Communications.
So what’s the verdict?
Satellite has many benefits, but much like broadband LTE it has a number of drawbacks making it difficult to solely rely on for critical communications. The emerging trend is convergence of multiple networks, to take advantages of the bandwidth and coverage of satellites, while falling back to LMR coverage to ensure continuity of service. New Zealand’s PSN network chose P25 digital radio for the backbone of their nationwide critical communications network, but this does not exclude the potential for adding satellite comms into their mix in the near future.
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