Silo Protection

ROP system in Nuclear Security Force Vehicle
MPU5 systems can be vehicle-mounted to enable mobile SFGs to remain in touch with dismounted personnel. The ATAK-based situational awareness system is also shown in this picture displayed on the screen.

The US Air Force’s ballistic missile force is receiving important communications enhancements to help protect it from hostile actions on US soil.

The United States Air Force’s (USAF) Intercontinental Ballistic Missile (ICBM) force is built around Boeing’s LGM-30G Minuteman-III missile. The air force says it maintains a fleet of 400 LGM-30Gs spread across three formations. The 90th Missile Wing (MW) is headquartered at the FE Warren airbase, Wyoming. The 341st MW is headquartered at Malmstrom airbase, Montana with the 91st MW is headquartered at Minot airbase, North Dakota.

The 90th MW has LGM-30G silos deployed across a 9,600 square-mile (24,863 square-kilometre) area which includes parts of eastern Nebraska, northern Colorado and eastern Wyoming says the USAF. 341st MW siloes are deployed across an even larger area. This comprises 23,500 square miles (60,864 square kilometres). Meanwhile the 91st MW’s silos are deployed across an area of 8,500 square miles (22,014 square kilometres). Having siloes distributed across such a large area makes sense, reducing the likelihood that siloes bunched together could be destroyed by an incoming salvo of hostile warheads.

Nuclear Security Force

Protection of these facilities is the responsibility of the USAF Security Forces which contain the Nuclear Security Force (NSF). Each missile wing has an organic NSF. The 91st MW has the 91st Security Forces Group (SFG) which has two subordinate Missile Security Force Squadrons (MSFSs). The 341st MW has the 341st SFG with three MSFSs while the 90th SFG has a single MSFS.

The MSFSs provide force protection to LGM-30G siloes which are often in austere locations with sporadic ultra-high frequency (300 megahertz to three gigahertz) radio coverage with no data carriage. Large portions of the states of North Dakota, Montana, Wyoming and parts of Nebraska also lack any cellular coverage. As a result, the USAF has embarked on an overarching modernisation of the NSF’s communications systems called the Regional Operating Picture (ROP). ROP relies on Persistent Systems’ Infrastructure-based Regional Operation Network (IRON). This is comprised of MPU5 Multiple-In/Multiple Out (MIMO) tactical radios and integrated antennas. The hardware in turn employs the company’s Wave Relay Mobile Ad Hoc Networking (MANET) waveform.

US Cellphone Coverage
Cellphone coverage in parts of the north-western United States can be sporadic particularly in areas where the USAF has its ICBM siloes as shown by the white areas in this graphic. This makes it imperative that the Security Forces Groups protecting these weapons have radio communications that work anywhere.


MIMO uses radios with multiple antennas and MPU5 transceivers have three. Each radio is transmitting three signals, all containing the same traffic, with each radio receiving these three signals. When a single radio signal is transmitted it moves through the air but can hit solid objects like buildings. This can cause interference, risking the signal becoming garbled and unclear when it reaches the other radio. Having three antennas provides three paths by which the signal can travel from one radio to another. Should one or two of these paths suffer interference, then there is still an additional path the radio can use. If all three paths work, even better, you will enjoy clear wideband communications. MIMO exists to greatly reduce the chances that signals will suffer interference and helps them resist jamming.

MPU5 radios come in five different flavours according to their frequency. The MPU5 RF-1150 uses frequencies of 1.350 gigahertz/GHz to 1.390GHz. The MPU-5 RF-2150 uses 2.2GHz to 2.507GHz, the MPU5 RF-2125 2.025GHz to 2.150GHz, the MPU5 RF-4100 4.4GHz to five gigahertz and the MPU5 RF-5100 5.1GHz to six gigahertz. All five provide over 100 megabits-per-second of data throughput using software configurable bandwidths of five, ten and 20 megahertz, according to company specifications.

On 1st March, Persistent Systems won a $75.5 million contract to provide its radios to the USAF according to a press release. These will provide voice, video, chat, data, and position, navigation and timing services to the SFGs. The press release continued that ROP entails the rollout of more than 1,000 fixed towers and vehicle-installed terminals. It connects SFGs to the wider USAF communications infrastructure. ROP lets them share situational awareness with other air force echelons and beyond the missile wings.

The press release continued that circa 75 IRON systems are being procured for the ROP’s 75 operations centres and over 1,000 vehicles. IRON can also receive information from sensors deployed to protect the ICBM infrastructure, like cameras. This data can be accessed by the SFGs across the ROP network.

IRON tower
IRON systems are deployed on static towers. They connect deployed units using ROP networks with higher echelons and vice versa. They can also carry sensor traffic to the Security Forces Groups and other echelons.

MPU5 systems can be vehicle-mounted to enable mobile SFGs to remain in touch with dismounted personnel. The ATAK-based situational awareness system is also shown in this picture displayed on the screen.

One useful element of the Wave Relay waveform is that MPU5 users get a continually updated ‘heat map’ of bandwidth levels available on a ROP network, says Adrien Robenhymer, Presistent Systems’ vice president of business development: “Now you know how much connectivity you have and how much bandwidth is available.” Bandwidths offered by Wave Relay let the security forces send and receive video in real time, something which is invaluable for situational awareness: “They can see the situation unfolding,” says Mr. Robenhymer: “You want information dominance so that you can get ready for anything.”

Roll Out

Mr. Robenhymer added that some ROP units are delivered and covering “high priority areas.” Training for both systems is straightforward as they use ATAK (Android Team Awareness Kit) tactical situational awareness software. This employs the Android operating system. ATAK forms the user interface for both IRON and ROP. Persistent Systems expect that the rollout of ROP should conclude by late 2025.

by Dr. Thomas Withington

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