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CoCom regulations and GPS receivers for balloons and cubesats
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- DeepHorus
The long-standing CoCom regulations that limit civilian GPS receivers at altitudes above 18 kilometers and speeds exceeding 1,000 knots are facing renewed scrutiny as hobbyists and aerospace engineers seek to use GPS in balloons and cubesat subsystems. While these dual-use restrictions were originally designed to prevent the use of GPS in ballistic missiles, recent hints of "more relaxed rules" have sparked confusion and debate within the community. The exact nature of these relaxed rules remains unclear, leaving many to wonder whether modifying firmware to remove these limits is now permissible.
CoCom, the Coordinating Committee for Multilateral Export Controls, imposed these limits decades ago to control the spread of sensitive technology. GPS chip manufacturers universally implemented them in firmware, typically using an AND logic: the receiver stops working only if both altitude and speed thresholds are exceeded simultaneously. However, for balloon-borne applications, altitude alone may trigger the limit if the logic is OR, which is a critical nuance for high-altitude balloons and cubesat testing.
The two key thresholds are 18 kilometers for altitude and 1,000 knots (approximately 0.5 kilometers per second) for speed. According to a 2020 Wired article, "more relaxed rules" now allow the use of GPS at higher altitudes and speeds, but the article did not specify what those rules are. References to modifying or hacking firmware to remove limits exist online, including forums and commercial products, indicating a demand for unfettered GPS receivers.
The ambiguity has practical consequences. For example, a balloon carrying a cubesat payload might exceed 18 km altitude at low speed, triggering the altitude limit if the logic is OR. Researchers and hobbyists need clarity on whether they can lawfully disable the limits themselves or procure modules without them. The lack of clear guidance could stifle innovation in high-altitude and space-related projects.
The space community has expressed frustration over the opaque regulations. One forum user noted, "The problem is people normally don’t know how to either construct their own receivers or disable/modify the limits inside ready available modules." While some manufacturers offer modules with relaxed limits for authorized users, the general public remains uncertain about what is allowed.
To resolve this, experts call for the relevant authorities to publish clear, updated guidelines on GPS receiver export controls. As small satellite and high-altitude balloon projects proliferate, the demand for high-altitude GPS capability will only grow. Without explicit rule changes or official interpretations, the practice of hacking firmware will likely continue in a legal gray area, potentially leading to compliance risks.
