Disclaimer: The TTGI mechanic is very elusive, even to veteran players. Below is my and Taisty's attempt at explaining it in a digestible way, using information collected from the game's official Discord server.


TTGI stands for Time To Go Intercept. It refers to the target switch prohibition game mechanic that prevents missiles from switching targets once they are below a certain time to impact, as calculated by the current speed and range to the target.

More specifically, any missile with a time to impact of less than 3 seconds will not switch away from the target they are locked on. However, the term TTGI Hybrid refers to a hybrid missile that uses this mechanic to lock onto the first target it sees.

So, lets go more into how this works!


First up is how seekers get targets, and the timing. Before any targets are locked, seekers check every 0.02 seconds to see if there is a target within their seeker cone.

After an initial target has been selected, the time between checking for new targets, and checking to see if it re-targets, is 0.5 seconds.

Additionally, any time there are multiple targets within the seeker cone when the seeker checks for targets, the missile rolls to see what it will target, favouring larger signatures.

So, where does the TTGI check fit into all of this?

Before a random selection of targets takes place, the seeker checks its Time To Go Intercept (TTGI) to the target. If that time is 3 seconds or less, then the seeker will not swap targets. This will occur unless the target is no longer seen by the seeker, or if it is no longer considered valid (due to a validator set to reject no longer validating the target).

Because the seeker can only swap its target 0.5 seconds after entering its seeker range, and because TTGI can then prevent it from swapping targets, you can make missiles that only stage on the first thing they see.

It was recently brought to my attention by d0d0b1rd that all hybrids have a StageIgnitionDelay of 0.5 seconds. If you remember how the ideal TTGI missile works, as outlined above, you might notice how this is horrific for their ability to ignore chaff, and, if my understanding is correct, should negate its ability to fully TTGI, causing chaff close behind the target to also have a chance to lure it.

This should in theory make it so TTGI missiles will move (cruise speed * 0.5) towards the target before it begins acceleration, causing it to also lock chaff that is (cruise speed * 0.5) behind the target, rather than ignoring it unless he chaff is in front of the target. This will be called Seeker Lookpast Distance for the sake of the calculator.

- TaistyCookie

Exploiting this mechanic is especially useful to make anti-capper and cap denial hybrid missiles (both size 2 and 3). These small ships usually come into control points at flank speed, and rarely have enough time to reverse course and put chaffs in front of themselves.

That being said, it is still useful into ships of all sizes, as larger ships with more mass take more time to come to a stop and turn around. Targeting small ships just usually means the missile gets more impact per point.

Note: This is only practical with ANS hybrid missiles that can achieve enough speed and acceleration to have a time to impact of less than 3 seconds after first spotting a target, if you are using an ACT-based main seeker.

By using this Interactive Hybrid Missile TTGI Calculator[www.desmos.com], you can skip all of the math and jump straight into finding a TTGI capable missile tuning.

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First, you need to create a new SGM-H-2 or SGM-H-3 hybrid missile in the Missile Editor. Make sure its main seeker is either Fixed Active Radar Seeker or Steerable Active Radar Seeker, this TTGI calculator assumes you are using either one of these. Then give it your desired backup seeker, warhead, guidance avionics, and a Cruise/Sprint Engine tuning close to what you need.

For best results, it is recommended that you have no terminal maneuvers, and your stage trigger is at exactly 2,000m from target.

Next, we will use the TTGI calculator to check if the current tuning is TTGI capable or not:

To use the calculator, you will need to find these 3 stats of your current tuning: Cruise Engine - Speed (Main), Sprint Engine - Speed (Main), and Sprint Engine - Accel:



Put them in the Missile Tuning section of the calculator in the left panel. Then check in the right panel if the red line and red dot labeled TTGI falls within the green area. If it is, then your missile is TTGI capable. Otherwise you will need to further modify your tuning.

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Keep adjusting and input each new tuning into the calculator until you have a TTGI capable missile with the tuning you want. Generally the higher your cruise and sprint engine speed is, the closer it is to become TTGI capable.

Keep note of the Seeker Lookpast Distance. This is the maximum theoretical distance for any chaff behind the target to be able to pull your TTGI missiles. Increases proportionally with cruise engine speed.

Quick disclaimer: This calculator makes some assumptions on factors that cannot necessarily be obtained - while there is a bit of leeway in the calculations, things like PID failure and the hybrid wobble are unfortunately not accounted for. These could cause the TTGI to fail at high angles to target. If you experience this, please tell us where it is inaccurate, so it can be fixed. Thank you!

Big shoutout to TaistyCookie who made the original TTGI Calculator. This version is simply a more polished one that's easier to use, but the underlying math is still the same. Also, massive thanks to d0d0b1rd, who provided basically all of the numbers you see here. Without him much of the information would still be unknown and/or inaccurate.