Planetary System Navigation

What is PSN?
Planetary System Navigation, or PSN, is the UNSC's method of navigating within a planetary or lunar system with ease and efficiency. It is designed in a way that is both understandable by the commanders of vessels and fleets to create battle plans and combat manoeuvres while also being quick and easy to put into a command console so it can be carried out in combat.

Its first variant, the Orbital Positioning Program (OPP), initially created in the 2100's, to make the tracking of vessels in the Earth's, the Moon's and Mars's orbits with ease, and for easy shipment moving. This was then create and improved by the military in the Interplanetary Wars in the mid to late 2100's with the UNSPKO developing a more effective system that is similar to the version now found in the 2500's (Installed in 2507).

How does it work?
First you have Sierra or section, every planet has eight sectors, which are squares of that divide the planets sphere of influence. There are six points of convergence of four of the sections, they are the north and south poles, and the four midpoints between the poles (on the equator) on equidistant meridians, they split the planet in four like a melon, these sections between the poles are split in two at the equator, creating eight equally sized planetary sections, there is always at least one SMAC in each section, (though larger populations or more important facilities may have more)

Secondly you have your X-Ray, Yankee and Zulu coordinates, these are simply height, length and breadth that extend from the convergence point (Alpha 1, 2, 3 is equal to Echo 1, -2, 3), that when put together give a point in 3D space, and along with a bearing of X&Y and X&Z, can give a rough flight path that a ship is taking. As for the point of origin, it is the centre of the planet

As for velocity, it is measured in its speed in the X, Y and Z. A speed of 3.43, 3.52, 3.12, is a speed of 33.9 km/s, that coupled with the baring will give you the velocity and Estimated Time of Closest Approach or ETCA, which is calculated with the velocities of both vessels, as well as distance that the encounter will be at, also known as Estimated Distance of Closest Approach (EDCA). This allows for a clever use of dumb weapons systems, like bullets, to hit their target, especially when coupled with an AI.

Sierra Charlie (Section), X-Ray 7345, Yankee 7156, Zulu 7503 (Section position), Bearing 41 (X&Y Bearing), 64 (X&Z Bearing). Speed 1.34(X), 1.13(Y),0.93(Z), with an ETCA of a minuet thirty-two. EDCA; 0.1 km.