ootk-core/src/coordinate/RIC.ts

Orbital Object Toolkit. A modern typed replacement for satellite.js including SGP4 propagation, TLE parsing, Sun and Moon calculations, and more.

/**
 * @author Theodore Kruczek.
 * @license MIT
 * @copyright (c) 2022-2025 Theodore Kruczek Permission is
 * hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the
 * Software without restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

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));
  }
}