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How to survive the ITU frequency filing process

In recent years, with the booming small satellite industry and the introduction of mega-constellation satellites in Low Earth Orbit, the need for satellite networks frequency coordination (which should be done through ITU frequency filing) has become more important than ever. However, as the radio frequency spectrum is limited and must be shared among many users, any other spacecraft can cause interference with yours and vice versa. 

The key objective of the ITU Radio Regulations (RR) is to avoid harmful radio interference.

Before finalizing any spacecraft design or operations plans, you must understand the core regulatory rules, including technical constraints, to enable sharing between systems in specific frequency bands. For example, you don’t want to design and build a system that violates regulatory rules. You can still correct issues found during the licensing process, but correcting them will cost a lot of time and money.

If this is your very first space mission, it is highly recommended to consult with organizations or individuals familiar with spectrum regulations during the mission definition/design phase to ensure compliance; and remember that it’s easier to prevent a problem than to fix it. 


Filing Process Steps: 

  1. Preparation for the filing
  2. Input, validate and submit API/A
  3. ITU publishes API/A
  4. Other administrations comment on API/A
  5. ITU publishes API/B
  6. Coordinate with other administrations
  7. Submit notification to ITU


Preparation for the filing

A typical small satellite would need at least two low-speed communication channels (one uplink for TC-telecommand and one downlink for TT-telemetry) and perhaps one more high-speed downlink channel for primary payload data if a high amount of data were collected in-orbit. In addition, specific missions require more RF spectrum, such as those carrying SAR (Synthetic Aperture Radar) and IoT (Internet of Things) payloads. While designing your mission, it is crucial to consider not using excessive amounts of RF spectrum since the available RF spectrum is a limited resource and has to be shared among many other satellite operators.


You must also complete your link budget calculation for every uplink/downlink channel. Many values such as receiving system noise temperature, maximum peak power, and EIRP will be required later for filling in the API (Advance Publication Information) form. Since orbit information is required for the API form, booking a launch opportunity early is highly advisable. If you need help booking a launch, contact Precious Payload; we are happy to help.

Orbit information input form for API filing.


The next important thing to prepare is identifying and contacting your notifying administration. This is usually the administration of the country where your ground station will be based (although it is possible to rely on another country instead). You may need to be a registered company/university/organization in this nation. You can find contact details for notifying administrations worldwide at: https://www.itu.int/online/mm/scripts/org_br_admin.list. For example, in the US, it is the Federal Communications Commission (FCC), in UAE — Telecommunications and Digital Government Regulatory Authority (TDRA), in the UK — Office of Communications, Ofcom International Frequency Coordination, in India — Indian National Space Promotion and Authorisation Centre (IN–SPACe or INSPACe), etc.


ITU Frequency Filing Process

There are three critical steps in the ITU submission process for satellite networks not subjected to coordination: 


  • API/A, 
  • API/B, and 
  • Notification. 


Note that this process is much simpler (faster and cheaper) than those subjected to the coordination process. For example, check the footnotes in the Table of Frequency Allocations in Article 5 of ITU Radio Regulations to know whether a frequency band is subject to coordination. Finding the specific technical requirements for your needs can be more complicated than it sounds, as the Radio Regulations comprise thousands of pages in four thick volumes – at least in their physical form. 


There is specialized software called Table of Frequency Allocations Software to provide a consolidated view of Article 5, with an easy way to search its content and perform specific calculations and modeling algorithms. It is available for order at the cost of 300 CHF (approx. $312) for a single-user license (up to 3 personal devices), or 600 CHF (approx. $624) for a 2-10 user license from https://www.itu.int/hub/publication/r-reg-rr5-2020/ 


The entire ITU frequency filing process will ideally take six months, but it will most likely take longer, up to 2 years or more, with complicated filings. It depends on several factors, such as your requirements for satellite orbit(s), uplink/downlink frequencies, bandwidth(s), transmitting power, the completeness of your filing (are all supporting documents, drawings, and schematics included), as well as how well you deal with coordination and/or ‘resolution of difficulties’ with other networks. 


If your mission is just a simple educational cubesat that requires only a few (2-3) beams and no other special requirements, you may want to try doing the filing on your own. On the other hand, if your mission has more complex requirements for radiofrequency spectrum (such as carrying SAR or IoT payload), and you have limited/don’t have prior experience with the ITU filing process, it is highly recommended to seek support from a company or an experienced Subject Matter Expert (SME) who did this before to help you expedite the process. 


Contact Precious Payload, and we can help to look into your specific mission needs to guide you in the right direction.



True Story 1: Startup X is developing a constellation of cubesats for IoT applications. They have already signed the Launch Service Agreement (LSA) with a Launch Provider (LP) and have secured a launch opportunity for the first mission in January 2023. They submitted the API/A filing to their notifying administration under a collaborating university’s name in May 2022. They had to wait three weeks to have it returned and asked to change the center frequency and a few other parameters. It took time for them to rework the filing and resubmit it (under the university’s name), and the filing is still under review at their notifying administration. As a consequence, the LP informed the company that they would not meet the January launch with the necessary licenses, and their flight would be delayed until at least April 2023. Further delays are expected if they cannot get the required ITU authorizations on time. 


Lessons learned:

  • The frequency filing process takes a long time—with a lot of paperwork and bureaucracy involved—so try to start it as early as possible.
  • If you don’t have experience, hire a specialist to review your filing(s) to ensure all information is accurate and validated before submission. This saves time and money.

The regulatory process for satellite networks not subject to coordination.


An API (Advanced Publication Information) is the first submission required by the ITU. By submitting it, you inform the ITU and other administrations of your preferred frequency band, the number of uplinks/downlinks, and many other parameters of your communication subsystem/payload and associated ground stations. 


Notifying administrations (of other countries) will look at your API filing to decide whether or not your satellite network is likely to cause harmful interference to their existing networks. If this is the case, they need to submit a comment. It is best to keep values quite general (for example, don’t choose a specific frequency like 432.675MHz for your downlink but rather keep it in a range like 430 – 435MHz) at this step. In addition, you will have more room to maneuver when coordinating with other administrations later. Also, avoid common mistakes while filing the API, such as choosing MHz vs. GHz, missing or having more ‘0’ in the frequency input field. Having at least two people cross-check all fields in the filing is a good practice.


You should submit your API to your notifying administration, who will send it to the ITU. The notifying administration will likely charge a fee for processing your filing from country to country. Establish contact with them early to explain your mission and gain support. Also, expect some waiting time as they have to deal with many other filings. 


As soon as the ITU (BR- Bureau) receives your API filing, they will publish it to the “as-received” list of Satellite Network Filings. Access this list here: https://www.itu.int/ITU-R/space/asreceived/Publication/AsReceived It is essential to highlight the ever-increasing number of satellite notices submitted to the ITU and the amount of administrative paperwork they have to deal with. Currently, the ITU charges a flat fee of 570 CHF (approx. $600) to process an API filing of a satellite network in LEO (not subject to coordination).


List of satellite notices received (but not yet published) by the ITU.


The ITU will then publish an API/A within three months. Try to maintain a good relationship with your notifying administration and keep in close contact with them so you can respond to any comments promptly.

After the ITU publishes the API/A, other administrations are given four months to submit comments. After this period has elapsed, the ITU will publish an API/B. The API/B will contain definitive coordination requirements to help you coordinate with other administrations. 

Following API/B publication, it is now possible to coordinate with other administrations. This process involves replying to the comments submitted by administrations and addressing any concerns they may have raised. 


All correspondence with administrations should be made through your notifying administration, so there will be a lot of back-and-forth communication. Therefore, it is critical to keep in close contact with your administration to quickly update you with any comments from other administrations. Be ready to draft responses to these comments.

This process should take a minimum of two months. Once all comments have been resolved, you can submit a notification to the ITU. The notification submission is similar to the API/A submission, except more specific values are expected, and additional parameters are required. If following the coordination period, selecting values in the bands identified in your API/A for Notification is impossible. It may be necessary to submit a new API/A targeting a different frequency band. This is the reason you must choose the bands wisely back in the API/A step.


True Story 2: A university team worked on a cubesat mission and submitted the necessary API filings to the ITU. When they were about to submit the Notification, the project sponsor requested a name change for the cubesat. To the sponsor, it’s just a simple change of the text, while in reality, the university team had to submit a lot of paperwork to notify their administration and the ITU to get it done. Luckily, they had started the process very early and made it in time before the launch.


Lessons learned:

  • Get approval from all project stakeholders and decide on the mission’s name early.
  • Start the ITU filing process early to allow for unexpected, last-minute changes.


International Amateur Radio Union (IARU)

Suppose your mission falls under the amateur radio category. In that case, it will be necessary to coordinate with the International Amateur Radio Union (IARU) in addition to the above steps during the frequency filing process. By using amateur radio bands, you may not have to pay the frequency filing fee(s); however, you must remember that it is strictly not for commercial use. However, there are many cases where requests from university teams were declined because of the absence of an amateur mission.


Detailed step-by-step instructions from ITU for potential amateur satellite builders can be found here: https://www.itu.int/en/ITU-R/space/Documents/ARS-tutorial.pdf


You can also find the current IARU frequency coordination status for new satellites at this link: http://www.amsat.org.uk/iaru/. New satellite developers are highly recommended to go through both lists of satellites for which frequencies have been coordinated (http://www.amsatuk.me.uk/iaru/finished.php) and satellites for which Frequency Coordination has been declined (http://www.amsatuk.me.uk/iaru/declined.php) to get more information.

Lists of Satellites for which frequencies have been coordinated.


API/A Guide

The ITU has written a guide for completing an API using ITU’s tools SpaceCap and SpaceVal. You can find this at: https://www.itu.int/en/ITU-R/space/workshops/2015-prague-small-sat/Presentations/ARS-API_help.pdf


The trend of developing and utilizing small satellite technologies is a global phenomenon that can benefit the entire world. In addition, the ITU is developing the ITU-R Small Satellite Handbook to provide detailed guidance on the regulatory environment and procedures (specifically the application of the Radio Regulations) for administrations, small satellite operators, and service providers in the study/research, design, launch, and application of small satellites.


This is a work in progress, and the document can be downloaded from ITU here:                                        https://www.itu.int/en/ITU-R/space/Documents/Working%20Document%20on%20Developing%20an%20ITU-R%20Small%20Satellite%20HB_WP%204A.pdf


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  • Alan June 28, 2022

    Wow, that would be sooooo helpfull for the new satellite projects teams, well done PL !!!

  • Marina Kolyvanova July 14, 2022

    Thanks, Alan, for your feedback!