Glide Vehicle Research Articles

Trajectory Estimation of Hypersonic Glide Vehicle Based on Analysis of Aerodynamic Performance

Due to high speed and high maneuverability of hypersonic glide vehicles (HGVs), the state estimation of such targets has always been a research hotspot. In order to improve accuracy of the trajectory estimation, a nonlinear aerodynamic parameter model for target estimation based on aerodynamic performance analysis is proposed. Firstly, the dynamic characteristics of the hypersonic glide vehicle during the hypersonic gliding stage was analyzed. Then, aiming at HTV-2-liked vehicle, the engineering calculation method was used to form the reference aerodynamic model for the target estimation. Secondly, a deviation model described by first-order Markov process was introduced to compensate the uncertainties of the unknown maneuver information from the target. Finally, extended Kalman filter was utilized to estimate the state of the target. The simulation results show that the proposed model is able to improve the accuracy of acceleration estimation for the HTV-2-liked hypersonic gliding vehicles.

Analysis of signal-to-noise ratio for space-based infrared detection of intercontinental glide vehicles

The infrared radiation of intercontinental glide vehicles (IGV) is significant during hyper-velocity flight due to the serious aerodynamic heating. Our analysis and calculation show that the signal-to-noise ratio of infrared detection for IGV by the space tracking and surveillance system (STSS), which the United States is testing to deploy, will be between 103–105 in order in a short wave band around 2.7 μm, while the threshold values of signal-to-noise ratio for STSS to meet the track and recognition requirements are about 3 and 30, respectively. This means that STSS is very effective to IGV. In open argument of IGV penetration capability, the core standpoint is that it is difficult to predict the track of IGV due to its lateral maneuver. However, the lateral average acceleration capability of IGV is only about 0.15 g , while the US missile defense system was reported to have the ability to transmit the target information obtained by the detection system to its command system and interceptor missile in time. Through quantitative estimation, it is easy to prove that IGV orbital maneuver can not only predict, but also have high accuracy by using space-based infrared detection, so the argument of “difficult to predict” is not valid.

Conceptual Design of an Unmanned Fixed-Wing Aerial Vehicle Based on Alternative Energy

This paper focuses on the aerodynamics and design of an unmanned aerial vehicle (UAV) based on solar cells as a main power source. The procedure includes three phases: the conceptual design, preliminary design, and a computational fluid dynamics analysis of the vehicle. One of the main disadvantages of an electric UAV is the flight time; in this sense, the challenge is to create an aerodynamic design that can increase the endurance of the UAV. In this research, the flight mission starts with the attempt of the vehicle design to get at the maximum altitude; then, the UAV starts to glide and battery charge recovery is achieved due to the solar cells. A conceptual design is used, and the aerodynamic analysis is focused on a UAV as a gliding vehicle, with the calculations starting with the estimation of weight and aerodynamics and finishing this stage with the best glide angle. In fact, the aerodynamic analysis is obtained for a preliminary design; this step involves the wing, fuselage, and empennage of the UAV. In order to achieve the preliminary design, an estimation of aerodynamic coefficients, along with computational fluid dynamics analysis, is performed.

Asymmetric arms control and strategic stability: Scenarios for limiting hypersonic glide vehicles

ABSTRACTCan arms control incorporate emerging technology? Other articles in this special issue identify potential risks emerging technologies pose to stability and how they are intertwined with international politics. Is there a future for multilateral strategic arms control? This article looks ahead to explore how arms control might reduce those risks but in order to do so we must update concepts of both arms control and strategic stability. Building on Thomas Schelling and Morton Halperin’s seminal study into the relationship between strategic stability and arms control, this article offers an original framework – asymmetric arms control – for incorporating new technologies, which is then used to identify six scenarios for arms control of hypersonic glide vehicles (HGVs). It concludes that arms control can potentially reduce the risks to strategic stability associated with emerging technologies by incorporating dynamism into arms control design. Ultimately, asymmetric arms control can best contribute to strategic stability by crossing domains and reflecting the cross-domain nature of international conflict, and the framework has potential application to emerging technologies beyond HGVs.

Performance comparison between waverider and wide-speed-range gliding vehicle based on CFD approaches

Wide-speed-range gliding vehicle (WSRGV) is designed to adapt to the variable cruising environment that hypersonic vehicles will encounter during the mission implementation. Based on the cone-derived theory, a novel design technique of WSRGV has been developed. Theoretically, the functional relationship between cone-derived waverider’s volumetric efficiency and its design Mach number can be built through sampling approach as long as the geometries of design conical shock wave and the upper base curve are fixed. Based on the functional relationship, a cone-derived waverider that owns the same volumetric efficiency with a giving WSRGV can be acquired. This paper compared the aerodynamic performance between WSRGV and the cone-derived waverider sharing the same volumetric efficiency in a wide Mach number range. Their aerodynamic properties versus angle of attack have also been compared under the waverider’s design Mach number. The obtained result shows that WSRGV shares similar aerodynamic performance with the cone-derived waverider with the same volumetric efficiency. The aero-surfaces in the margin area of this kind of configuration have a larger contribution to the lift-to-drag ratio in comparison with the aero-surfaces in the central area. The configuration with a thick central body and thin margin place owns not only better aerodynamic performance but also better loading property.

Extended deterrence and assurance in an emerging technology environment

ABSTRACT How do emerging technologies impact strategic stability in the international system? I focus on how one aspect of strategic stability, extended deterrence commitments inherent to alliances, may be impacted by the development of new technologies and capabilities. I ask how technological innovations will impact the market deterrence and assurance dynamics in particular. I argue that while technologies may enhance the ability to provide extended deterrence, allies may be less assured by these new capabilities. To test these hypotheses, I explore emerging capabilities in new domains such as drones and hypersonic glide vehicles on international stability.

Dynamics and Control for Hypersonic Gliding Vehicles Equipped with a Moving Mass and RCS

AbstractTo solve the problems of a hypersonic unpowered gliding reentry vehicle controlled by only one actuator, a combination bank-to-turn control mode with a moving mass and nonredundant reaction...

Entry trajectory generation with complex constraints based on three-dimensional acceleration profile

A new entry trajectory generation based on three-dimensional acceleration profile is proposed for hypersonic glide vehicles, meeting range requirement while taking waypoint and no-fly zone constraints into consideration. Firstly, the path constraints, such as maximum dynamic pressure, total overload and peak heating flux at the stagnation-point, are transformed into longitudinal and lateral flight corridors. And the initial lateral and longitudinal sub-profiles are obtained in sequence based on a layered strategy. Secondly, in order to accurately guide the vehicle to reach a target, a method based on Newton's iterative and bisection search is proposed, and the three-dimensional acceleration profile satisfying the mission requirement is quickly obtained. Further, this approach is extended to accommodate the trajectory generation with regarding the waypoint and no-fly zone constraints. Finally, a three-dimensional tracking law is designed to follow the reference trajectory, verifying the feasibility and accuracy of the proposed method.

Mapped Chebyshev pseudospectral methods for optimal trajectory planning of differentially flat hypersonic vehicle systems

This paper presents a novel trajectory planning algorithm for hypersonic glide vehicles based on differentially flatness theory and mapped Chebyshev pseudospectral method (MCPM). Firstly, the flatness property of a hypersonic glide vehicle dynamics system is extended explicitly by introducing a pseudo control input along the opposite direction of aerodynamics drag. In this way, all the states and controls of the system can be represented by flat outputs and their derivatives, and the trajectory planning problem is formulated into the flat output space with differential constraints entirely eliminated. Secondly, the optimization problem in the flat output space is converted into a nonlinear programming one via the mapped Chebyshev pseudospectral method. The MCPM employs the conformal mapping principle to discretize the flat outputs at the time interval, in terms of which, the closely clustered Chebyshev points near the boundary are stretched and the ill-conditions of the differential matrix is improved. The Barycentric Lagrange interpolation algorithm is then utilized to interpolate the flat output functions, which is seized of better approximation properties than polynomial interpolation. Finally, the transformed nonlinear programming problem are solved by sequence quadratic program technique. The states and controls are then generated by the expressions of the flatness outputs. At the end of this paper, numerical simulations are performed to evaluate the proposed approaches, and comparisons are made with traditional methods. Simulation results demonstrate that the proposed differentially flatness based mapped Chebyshev pseudospectral method possessed better computing efficiency than traditional ones without losing the merits of high precision.

Optimal trajectories and normal load analysis of hypersonic glide vehicles via convex optimization

Hypersonic trajectory optimization has been intensively investigated through different approaches; however, the normal-load-optimal entry problems were barely studied and reported in the literature. Finding the optimal trajectories with maximum or minimum peak normal load is essential to evaluate the maneuverability and structural strength of the vehicle. In this paper, both the maximum and minimum peak-normal-load entry trajectories are explored using convex optimization. Based on the previous work, the maximum-peak-normal-load entry problem is firstly addressed by a Big-M method and a line-search approach. Through successive relaxations, the nonconvex discrete-event optimal control problem associated with maximum-peak-normal-load entry is transformed into a sequence of mixed-integer convex optimization problems. Then, a line-search technique is introduced to improve the convergence of the proposed method. Additionally, a sequential convex programming method is designed to solve the minimum-peak-normal-load entry problem to comprehensively analyze the normal load during the entry flight. There are efficient solvers that can solve each relaxed convex subproblem with a global optimum if the feasible set of the subproblem is nonempty. The convergence and accuracy of the proposed methodologies are demonstrated by numerical simulations, and the feasibility of the converged solutions is discussed based on an entry-corridor approach.

Improved artificial potential field based lateral entry guidance for waypoints passage and no-fly zones avoidance

In this paper, a novel improved artificial potential field based lateral guidance algorithm for waypoints passage and no-fly zones avoidance is proposed. By introducing the improved attractive potential field and the improved repulsive potential field, the proposed algorithm converts the waypoints passage problem and the no-fly zones avoidance problem into the reference heading angle determination problem. Based on the heading error threshold and heading angle constraints, the reference heading corridor can be obtained in real time, which is adaptively updated during the entry flight according to the waypoint and no-fly zone constraints. Then the bank reversal logic is employed to regulate the sign of the bank angle, control the lateral motion of the vehicle, and steer the vehicle successfully to the desired terminal zone without any collision of the waypoint and no-fly zone constraints. The simulation results for verification and comparison cases show that the proposed algorithm has better adaptability, applicability and robustness than the alternative methods, and it can be successfully applied in lateral entry guidance of hypersonic glide vehicles with waypoint and no-fly zone constraints.

Free Form Deformation Method Applied to Modeling and Design of Hypersonic Glide Vehicles

The aerodynamic shape of the hypersonic glide vehicle (HGV) has become a research topic nowadays due to its excellent aerodynamic performances. Some limitations need to be reduced when the free-form deformation (FFD) method is applied to parametric modeling and design of an HGV. In this paper, a typical lifting body is considered as an example, and we propose a border-based FFD modeling method that transforms the boundary of FFD lattice into the border of the windward side. Then, the superiority of the border-based FFD modeling method is demonstrated by comparison with the traditional FFD modeling method, and the mesh quality parameters are used to validate the well-deformed model and good geometric continuity of the proposed method. Finally, the border-based FFD modeling method is applied to deformable modeling and aerodynamic simulation of three typical HGV shapes. The results show that the higher efficiency, wider design space, and better applicability are performed by using the border-based FFD modeling method that outperforms the traditional FFD modeling method, and this method we proposed can allow a designer to achieve the better aerodynamic shape of HGVs.

Multiple Model Tracking for Hypersonic Gliding Vehicles With Aerodynamic Modeling and Analysis

The multiple model tracking methods for hypersonic gliding vehicles (HGVs), which improves the design of tracking model-set is proposed in this paper. Different from the traditional tracking method with dynamic pressure models, the proposed method refines the model-set by modeling and analyzing the specific aerodynamic characteristics of the HGVs. Based on the aerodynamic model of the vehicle, the novel tracking models are established and the multiple model tracking methods are adopted. The uniform model-sets are designed by determining the representative points from the constrained characteristic parameters to ensure the stability of the tracking system. Moreover, the model-sets are then augmented by the real-time updates of the motion estimations to further improve the tracking accuracy. The simulation studies indicate that the proposed tracking method outperforms the method with dynamic pressure models in both position and velocity estimations, the position estimation accuracy is increased by about 23%-53% and the velocity estimation accuracy is increased by about 42%-56% in the given examples.

Высокоточное конвенциональное оружие большой дальности и контроль над ядерными вооружениями

The article studies the development, production and deployment of high-precision long-range conventional weapons by the world’s leading military powers – the USA, Russia, and China. These weapons include non-nuclear systems with a range of more than 600 km capable of hitting the target by a single warhead with a probability of 0.5. The article focuses on air-, sea- and ground-based ballistic and cruise missiles, as well as hypersonic systems. The latter comprise cruise missiles with a scramjet engine and boost-glide complexes which rely on stages of ballistic missiles to boost a glide vehicle to hypersonic speeds. Hypersonics are less vulnerable for interception by missile defense systems. However, they also have a number of disadvantages of both technical and military-political nature. Existing high-precision long-range conventional weapons – with the exception of a massive attack scenario which is extremely unlikely in the absence of a full-scale war – can hardly have a significant impact on the balance of strategic nuclear forces. In the future, however, improvements in weapons performance, including hypersonic ones, will make it possible to transfer the core functions of strategic deterrence from nuclear to non-nuclear arms. Moreover, systems in question may aggravate strategic uncertainty due to their dual nature: they can carry both conventional and nuclear warheads and utilize support infrastructure for both conventional and nuclear military operations. Therefore, the use of highprecision long-range conventional weapons bears a high risk of a rapid escalation of an armed conflict all the way up to a massive nuclear exchange. The difficulty lies in the fact that traditional arms control measures are not applicable to high-precision conventional weapons. Their regulation should take a form of an incremental process with the final result likely to be less ambitious compared to nuclear arms control arrangements. A legally binding arms control regime for these systems would be hard to achieve mostly because it is virtually impossible to establish an effective verification regime. A more realistic alternative would be some form of parallel political statements on partial quantitative restriction for deployed long-range non-nuclear weapons and possibly limited data exchanges.

Analytical entry guidance for coordinated flight with multiple no-fly-zone constraints

This paper addresses the problem of coordinating a group of Hypersonic Glide Vehicles (HGVs) for the goal of simultaneous arrival in the presence of multiple No-Fly Zones (NFZs). Firstly, a high-precision analytical solution of flight time is derived from the nonlinear entry dynamics model built over a spherical and rotating Earth. Next, an entry guidance considering multi-NFZs and flight-time constraints is designed based on the new analytical flight-time formula as well as the existing 3-D analytical gliding-trajectory formulae. In the longitudinal part of the guidance, the flight-time and downrange formulae are used jointly to plan the longitudinal reference profile by considering both energy-management and flight-time requirements. In the lateral part, the downrange and crossrange formulae are used to plan the bank-reversal sequence according to the NFZ constraints. Additionally, in order to improve the accuracy of terminal time, speed, and altitude, a multi-objective iterative planning scheme employing onboard trajectory simulation is put forward and enabled at a time between the last two bank reversals to fine-tune the remaining short trajectory. In this scheme, the quasi-Newton method is improved by the use of directional derivatives such that the number of the trajectory simulations required to calculate the Jacobian matrix is reduced from 3 to 2 in each iteration, which greatly reduced the amount of calculation. Finally, a flight-time coordination scheme is developed for multiple HGVs to determine the starting times of entry flight, which can further determine the launch times once the boost guidance is specified. The superior performance of the guidance is demonstrated by Monte-Carlo simulations in stochastic disturbed circumstances.

Preliminary Analysis of the Hexafly-International Vehicle

Airbreathing hypersonic flight is an ongoing challenge with the potential to cut air travel time and provide cheaper access to space. Waveriders are potential candidates for achieving hypersonic cruise speed or proper acceleration within the atmosphere. Current research tends to focus on key issues like flight mechanics, thermal loading, aero-elasticity, aerodynamic and aerothermodynamics at hypersonic speeds. Design problems in each of these areas must be solved if the design of a hypersonic waverider-like vehicle is to be viable. In this framework, the HEXAFLY-INT project aims at testing in free-flight conditions an innovative gliding vehicle with several breakthrough on-board technologies to be launched along a suborbital trajectory. Its preliminary conceptual design has been carried out by means of tools suitable to design vehicles to fly in hypersonic conditions. Aerodynamic and trajectory analyses have been carried out to assess mission capability as well. Once the aeroshape and the reference mission have been identified, system and sub-system analysis have been performed to close the system loop. The main results of the design analysis carried out during the preliminary phase of the study (such as vehicle aerodynamics and aerothermodynamics, re-entry trajectories, structures and mechanisms, and on the overall system, as well), are presented in this work.

Research on State Estimation of Hypersonic Glide Vehicle

In order to estimate the motion state of the hypersonic glide vehicle, a motion model based on the aerodynamic parameters of the prototype CAV-H and an observation model of GEO infrared early-warning satellite were established. The exponential weighted recursive least square method with forgetting factor was used to measure the early-warning satellite observation data with measuring error in angle to obtain a fitting parameter describing the polynomial of the target state, The method can focus on the local motion of the target, dilute the influence of the early observation data on the fitting parameters, reduce the estimation error caused by the target manoeuvring. The simulation result shows that the estimation of both position and velocity of the hypersonic glide vehicle is highly accurate.

Gauss Pseudospectral Method Based Trajectory Optimization for Hypersonic Glide Vehicles

In order to meet the requirements of trajectory planning under complex constraints and avoid the occurrence of ballistic singularities, a set of motion models based on the idea of pole transformation is adopted, considering the influence of the earth rotation. Based on the model of pole transformation motion, the trajectory of hypersonic glide vehicle is simulated and some meaningful conclusions are obtained. Introduction

Research on the Maximum Range of Gliding Vehicles Based on Gauss Pseudo-spectral Method

Trajectory optimization is an important problem in the field of aircraft design. Effective trajectory optimization is critical to the tactical flight of an aircraft. Based on previous research, this paper further studies trajectory optimization of an unpowered gliding vehicle. The goal is to maximize its range and to analyze the influence of different initial conditions on trajectory optimization. In this paper, the trajectory optimization model involving all kinds of state constraints and control constraints was established and aerodynamic coefficient was calculated by CFD software. Finally Gauss Pseudo-spectral Method program was run to calculate the flight path of the gliding vehicle and to seek trajectory with maximum range. The simulation data shows that results of Gauss Pseudo-spectral Method are realistic and prove its practical operability. The use of Gauss Pseudo-spectral Method for trajectory optimization has a good effect.

Post-Pokhran II: Emerging Global Nuclear Order and India’s Nuclear Challenge

Post-Pokhran II the global nuclear environment has changed both in terms of developing niche technologies as also the nuclear strategies. Apart from the traditional challenges, there are new threats emerging in the form of cyber, space, hypersonic glide vehicles, nuclear terrorism, etc. The development of multiple nuclear dyads and triads further makes the security environment increasingly complex, as nations now have to deal with multiple nuclear problems and adversaries. While India has continued its progress in the nuclear domain since 1998, focused critique is necessary to ensure that India’s posture remains relevant and efficient in safeguarding sovereign interests. This article, thus, tries to analyse some of these issues and recommends that India needs to review its nuclear doctrine.