/**
 * @author @thkruz Theodore Kruczek
 * @license AGPL-3.0-or-later
 * @copyright (c) 2025 Kruczek Labs LLC
 *
 * 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 { EpochUTC, J2000, Tle } from '../main.js';
import { Thrust } from '../force/Thrust.js';
import { VerletBlendInterpolator } from '../interpolator/VerletBlendInterpolator.js';
import { Propagator } from './Propagator.js';
/**
 * Sgp4Propagator is a propagator that uses the SGP4 model to propagate the state of an object.
 * This class is useful for propagating multiple states with the same TLE, since it caches the
 * state of the TLE at different epochs.
 */
export declare class Sgp4Propagator extends Propagator {
    private readonly tle_;
    constructor(tle_: Tle);
    private cacheState_;
    private checkpoints_;
    /**
     * Gets the state of the propagator in the J2000 coordinate system.
     * @returns The J2000 state of the propagator.
     */
    get state(): J2000;
    /**
     * Calculates the ephemeris maneuver using the SGP4 propagator.
     * @param start The start epoch in UTC.
     * @param finish The finish epoch in UTC.
     * @param maneuvers The array of thrust maneuvers.
     * @param interval The time interval in seconds.
     */
    ephemerisManeuver(start: EpochUTC, finish: EpochUTC, maneuvers: Thrust[], interval?: number): VerletBlendInterpolator;
    /**
     * Performs a maneuver with the given thrust.
     * @param maneuver - The thrust maneuver to perform.
     * @param interval - The time interval for the maneuver (default: 60.0 seconds).
     * @throws Error if maneuvers cannot be modeled with SGP4.
     */
    maneuver(maneuver: Thrust, interval?: number): J2000[];
    /**
     * Propagates the state of the Sgp4Propagator to a specified epoch in J2000 coordinates.
     * @param epoch - The epoch in UTC format.
     * @returns The propagated state in J2000 coordinates.
     */
    propagate(epoch: EpochUTC): J2000;
    /**
     * Resets the state of the Sgp4Propagator by updating the cache state
     * to the current J2000 state of the TLE.
     */
    reset(): void;
    /**
     * Saves the current state of the propagator and returns the index of the checkpoint.
     * @returns The index of the checkpoint.
     */
    checkpoint(): number;
    /**
     * Clears all the checkpoints in the propagator.
     */
    clearCheckpoints(): void;
    /**
     * Restores the state of the propagator to a previously saved checkpoint.
     * @param index - The index of the checkpoint to restore.
     */
    restore(index: number): void;
}