As we noted, the purpose of the spectrum supportability risk assessment is to identify and assess regulatory, technical, and operational spectrum issues with the potential to affect the required operational performance of the candidate system. For example, in addition to determining that a system’s bandwidth requirement complies with an individual nation’s frequency allocation scheme, a new or modified system must also be evaluated with respect to:
• The system’s potential to cause interference to or suffer from other military and civilian RF systems currently in use or planned for operational environments.
• The effect of the system’s proposed spectrum use on the ability of the force structure to access the RF spectrum without interference.
• How the system’s spectrum use conforms to the tables of frequency allocation of intended host nations, ensuring regulatory protection from other national co-band spectrum users.
• If individual host-nation frequency allocations include enough bandwidth to fully support the system’s operational mission, for example, required data rate.
An SSRA should include the following components:
• Regulatory component: Addressing the compliance of the RF system with US national and international tables of frequency allocation as well as with regulatory agreements reached at the International Telecommunication Union.
• Technical component: Quantifying the mutual interactions between a candidate system and other co-band, adjacent band, and harmonically related RF systems, including the identification of suggested methods to mitigate the effects of possible mutual interference.
• Operational component: Identifying and quantifying the mutual interactions among the candidate system and other US military RF systems in the operational environment and identifying suggested methods to mitigate for possible instances of interference.
• E3 Assessment: At a minimum, EMC and EMI are to be addressed to determine the potential for interactions between the proposed system and its anticipated operational EME.
When conducting an SSRA, operational restrictions, availability of frequencies, host nation approval (HNA), and known incidents of electromagnetic interference (EMI) must be considered. S-D systems and equipment cannot be operated legally until they have been granted equipment spectrum certification (ESC) by National and DoD authorities; in addition, a frequency assignment must be obtained from the appropriate area frequency manager. For systems that will operate outside the United States & Possessions, an HNA also is requested prior to operation in each foreign country designated for use.
Additionally, the program must be monitored to determine the EMC and EMI impact of any changes to such operational RF parameters such as tuning range, emission characteristics, antenna gain and height, bandwidth, or output power, etc. Changes to these parameters may require additional E3 analyses or tests. The E3 Assessment should:
• Identify and resolve co-site EMI issues during system acceptance testing.
• Demonstrate repeatable EMC utilizing appropriate development models.
• Maintain system E3 design integrity during operations.
• Implement procedures for EMI problem reporting.
Producing an SSRA isn’t a trivial exercise! Next time we’ll take a look at some of the challenges in putting an acceptable product together.
-Brian Farmer
