Thread by @FRHoffmann1

This thread is discussing TERCOM guidance. There is a lot of mis- & disinformation circulating, partially fueled by the 🇩🇪 government itself, regarding the capabilities & requirements of TERCOM in relation to Taurus. Let's clarify the facts & set the record straight. 🧵👇 1/22

Terrain Contour Matching, or TERCOM, is a navigation system utilized in cruise missiles. It compares a contour map of the overflown terrain stored in the onboard computer of the missile with measurements taken during flight by an onboard radar altimeter (see picture above). 2/22

Why is TERCOM useful? Every cruise missile relies on a basic navigation system called inertial measurement unit which measures changes in velocity and rotation of the missile to calculate its position in space. 3/22

The issue lies in the fact that these calculations can be inaccurate, and any errors in the calculations will compound over time. This is because the current position is calculated based on the previously incorrect position. We refer to this problem as "integration drift". 4/22

To overcome this issue, another type of navigation system is required that updates the missile regularly on its "true" position in space, as opposed to the calculated position. In case any deviations occur, the missile can course correct. One such system is TERCOM. 5/22

TERCOM compares the stored onboard altitude data with the measured altitude data. If the measured value matches the stored value, the missile confirms that it is on track. If the values differ, the missile recognizes the need for course correction. 6/22

To make TERCOM work, you need a substantial amount of topographical data, or as Chancellor Scholz would say, geodata. Targeting analysts must meticulously plan the route by inputting numerous altitude values that correspond to individual coordinates along the trajectory. 7/22

This process is complex, not because it's inherently difficult, but because it is very time-consuming (48-72 hours in the 1990s). While modern software and processing power can likely expedite the process, it is still expected to require a considerable amount of time. 8/22

Topographical data is neutral. It provides altitude values for various coordinates, but no militarily sensitive information in itself. It therefore remains unclear why the chancellor deems it more "sensitive" than the type of actual targeting data the West already provides. 9/22

How do we obtain topographical data? During the Cold War, both the United States and the Soviet Union relied on satellite photography and a process called "stereogrammetry." Nowadays, the easiest method is to utilize synthetic aperture radar (SAR) satellites. 10/22

A SAR satellite emits microwave pulses, records their reflections, and analyzes the time delay to create high-resolution 2D/3D images of Earth's surface. In doing so, it is very useful in creating TERCOM maps. 11/22

On top of their military applications, SAR satellites serve several civilian purposes, such as determining forest height & deforestation, for example. In addition to state agencies, several private companies operate SAR satellites and offer their services to state actors. 12/22

As chance would have it, ICEYE, a private satellite provider, announced in August 2022 that it is granting Ukraine access to its SAR satellite constellation. Ukraine therefore does not need to launch its own satellites to create TERCOM maps. 13/22 iceye.com/press/press-re…

🇺🇦 is working on several cruise missile programs, including the Korshun land-attack cruise missile that more than likely will incorporate TERCOM. There is no doubt in my mind that 🇺🇦 already has access to the required geodata or can easily get there. 14/22

https://twitter.com/John_A_Ridge/status/1698038793322848579

Scholz's argument against delivering Taurus, based on the claim that sensitive & complex geodata is required, is self-defeating. The data is not sensitive (compared to what has already been provided), & 🇺🇦 likely has access to it, regardless of 🇩🇪 deliveries. 15/22

For those saying that Taurus can only be made to work with German geodata: Why would countries like Spain and South Korea agree to import the system if this was the case? Naturally, they have a need to use their own geodata and would otherwise not have imported it. 16/22

Ukraine would also not need to depend on Germany for assistance to program trajectories (contrary to what has been stated). If provided with training on the mission planning software, similar to 🇰🇷 and 🇪🇸 operators, Ukrainians could enter the TERCOM data themselves. 17/22

Consequently, there is no "constitutional" issue that would hinder Germany from delivering Taurus without parliamentary agreement. The presence of German operators in Ukraine is not essential for TERCOM to function, as long as adequate training is provided. 18/22

Finally, even if we give the chancellor all the benefit of the doubt, & 🇺🇦 would not be able to make TERCOM work for whatever reason, Taurus would still be a useable system. In this case, GPS and not TERCOM would provide updates on the missiles "true" position in space. 19/22

Given the planning requirements for TERCOM, it is unrealistic to expect 🇺🇦 to rely on it for every attack, especially when time-sensitive targets are involved. While TERCOM is valuable, especially due to its better jamming reistance, Taurus operates effectively without it. 20/22

So let me say it one more time for those in the back: There are no technical or legal obstacles preventing the delivery of Taurus and its accompanying geodata to Ukraine. The issue lies solely in the absence of political will and courage, not with the weapon system itself. 21/22

Just like in previous instances of weapon deliveries, such as artillery, IFVs, and tanks, Scholz is attempting to create artificial legal and technical obstacles to draw out the delivery process. This tactic is not new for Scholz; we've seen it before in the SPD playbook. 22/22

Reminder that I'm also on Bluesky, so feel free to follow me over there if you don't do so already.