ootk/src/coordinate/RIC.ts

Orbital Object Toolkit including Multiple Propagators, Initial Orbit Determination, and Maneuver Calculations.

/**
 * @author @thkruz Theodore Kruczek
 * @description Orbital Object ToolKit (ootk) is a collection of tools for working
 * with satellites and other orbital objects.
 * @license AGPL-3.0-or-later
 * @copyright (c) 2025 Kruczek Labs LLC
 *
 * Many of the classes are based off of the work of @david-rc-dayton and his
 * Pious Squid library (https://github.com/david-rc-dayton/pious_squid) which
 * is licensed under the MIT license.
 *
 * Orbital Object ToolKit is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Affero General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * Orbital Object ToolKit is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License along with
 * Orbital Object ToolKit. If not, see <http://www.gnu.org/licenses/>.
 */

import { Matrix } from '../operations/Matrix.js';
import { J2000 } from './J2000.js';
import { RelativeState } from './RelativeState.js';

/**
 * Represents a Radial-Intrack-Crosstrack (RIC) coordinates.
 */
export class RIC extends RelativeState {
  /**
   * Gets the name of the RIC coordinate system.
   * @returns The name of the RIC coordinate system.
   */
  get name(): string {
    return 'RIC';
  }

  /**
   * Creates a new RIC (Radial-Intrack-Crosstrack) coordinate from the J2000 state vectors.
   * @param state - The J2000 state vector.
   * @param origin - The J2000 state vector of the origin.
   * @param transform - The transformation matrix.
   * @returns The RIC coordinate.
   */
  static fromJ2000Matrix(state: J2000, origin: J2000, transform: Matrix): RIC {
    const dr = state.position.subtract(origin.position);
    const dv = state.velocity.subtract(origin.velocity);

    return new RIC(transform.multiplyVector3D(dr), transform.multiplyVector3D(dv));
  }

  /**
   * Creates a RIC (Radial-Intrack-Crosstrack) coordinate system from a J2000 state and origin.
   * @param state The J2000 state.
   * @param origin The J2000 origin.
   * @returns The RIC coordinate system.
   */
  static fromJ2000(state: J2000, origin: J2000): RIC {
    return RIC.fromJ2000Matrix(state, origin, RelativeState.createMatrix(origin.position, origin.velocity));
  }

  /**
   * Transforms the current RIC coordinate to the J2000 coordinate system using the provided origin and transform
   * matrix.
   * @param origin The origin J2000 coordinate.
   * @param transform The transformation matrix.
   * @returns The transformed J2000 coordinate.
   */
  toJ2000Matrix(origin: J2000, transform: Matrix): J2000 {
    const tt = transform.transpose();
    const tr = tt.multiplyVector3D(this.position);
    const tv = tt.multiplyVector3D(this.velocity);

    return new J2000(origin.epoch, origin.position.add(tr), origin.velocity.add(tv));
  }

  /**
   * Transforms the current RIC coordinate to the J2000 coordinate system using the provided origin.
   * @param origin The origin J2000 coordinate.
   * @returns The transformed J2000 coordinate.
   */
  toJ2000(origin: J2000): J2000 {
    return this.toJ2000Matrix(origin, RelativeState.createMatrix(origin.position, origin.velocity));
  }
}