G-Plane Drives
The earliest grav drives, in common use up to about the end of Archaic times, used the G-Plane system. Crude gravity fields generated by simple Pattonetti Emitters were used to push against control surfaces on starships.

The Pattonetti Emitter is the most basic element in gravity control. It was not, as some believe, actually developed by Pattonetti himself, but posthumously named to honour him as the father of gravity. In its most basic form, the Pattonetti Emitter is simply a wide-area quantum field generator tuned to incite a gravity field in the shape of the quantum field itself. Early generators were relatively uncontrolled, creating a “glob” of gravity which was loosely controlled by stimulating the Elegant emission of gravites along the surface of an object. As our understanding of modern physics progressed, it became possible to more precisely control the parameters of the quantum field and the rate of gravite emission, eventually leading to the direct manipulation of the actual conduction and decay of the gravite in the Manifold dimensions. Today, a set of four Pattonetti emitters can create a three dimensional, highly controlled field with varying degrees of gravity throughout.

In G-Plane drives, Pattonetti Emitters would generate crude gravitational globs that pushed or pulled against external control surfaces on the ship. The control surfaces could be dedicated physical structures or points of effect could be designated on existing portions of the hull. The manoeuvrability and acceleration of these early drives were highly dependent on the size and quality of both the emitters and the control surfaces. Damage or wear to either lead to a degradation of overall maoueverability. Maintenance in starship applications could be awkward, as the large control surfaces generally had to be outside of the ship hull. External control surfaces isolated the action of the navigational gravity from the centralized banks of Pattonetti emitters that maintained internal gravity and protected the crew, cargo, and structure from acceleration forces.

GravNet
Early Archaic Times saw the introduction of the modern GravNet drive system, in which external control structures are replaced by a network of internal "gravity conduits". Gravity conduits form a web throughout the hull of the ship and provide of both reinforcement to the physical structure of the ship and function as Eraerion Tubes. Gravity is induced against the inner surfaces of the Eraerion Tubes to manoeuvre the ship.

Eraerions are the gravity conduits developed by Hirsel Eraerion. They are sealed, powered tubes containing a quantum field. They can be incited to generate a polarized gravitational field which pushes on one side of the tube's interior and pulls on the other. They are generally snaked through the interior of a vehicle or starship and provide the control surface against which gravity works to propel the vehicle.

The GravNet system is very complicated, combining elements of modern physics and cutting edge bio-intelligence. The gravity conduits run throughout the hull of the entire ship and work in tandem. While a set of Eraerions are pushing one side of a ship in a certain direction, complimentary Eraerions will be inducing opposite forces on the opposite side of the ship, reinforcing the motion. In addition, the navigational gravity must work against the “real” gravity present outside the ship and cannot mingle with environmental gravity generated for the sake of crew and cargo.

Environmental gravity is maintained by a network of Pattonetti emitters. The emitters create local gravity in pockets formed around the skeletal navigation network of Eraerion Tubes. The environmental gravity system also coordinates a separate grid of Pattonetti fields that act to support and reinforce the starship hull itself, modulating at their edges to compensate for accelerations and stresses on the vessel's structure. Starship hulls themselves are not only made of ultra-strong modern nano-composites but are also articulated, formed of layers that move slightly in relation to one another and help absorb gravitational stresses.  

The Feednet supplies power to distributed local Gravity Control Hubs, Environmental Gravity Emitters, and the Eraerion Tubes themselves. Each Control Hub controls the gravity system for a designated section of the ship. There may be redundancy in their areas of effect, so that if one section loses gravity, it can be compensated for by neighbouring emitters. The Control Hub consists of a large Congenial Encephalon which coordinates power distribution from the Feednet and the function of the Navigational Eraerions and Environmental Emitters. The Congenial Encephalons, being congenial, work together to decide the most efficient method of actualizing the directives received from the navigational command system.