Navy - 24.2 SBIR - Alternative Navigation System for Hypersonic Vehicles in Global Positioning System (GPS)-Degraded and GPS-Denied Environment

Navy - 24.2 SBIR - Alternative Navigation System for Hypersonic Vehicles in Global Positioning System (GPS)-Degraded and GPS-Denied Environment

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N242-075 TITLE: Alternative Navigation System for Hypersonic Vehicles in Global Positioning System (GPS)-Degraded and GPS-Denied Environment

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Hypersonics; Integrated Sensing and Cyber;Microelectronics

OBJECTIVE: Develop a navigation system that can provide precise navigation for the entire flight trajectory of hypersonic vehicle operating under GPS-degraded/denied environments.

DESCRIPTION: Naval aerial platforms traditionally rely on GPS signal technology for positioning, navigation, and timing (PNT) system application. When a hypersonic vehicle is traveling at hypersonic speed through the atmosphere, a plasma sheath envelops the aerial vehicle because of the ionization and dissociation of the atmosphere surrounding the vehicle [Refs 1-3]. The plasma sheath prevents radio communication, telemetry, and GPS signal reception for navigation [Ref 4]. This radio "blackout" period poses a serious challenge for GPS-enabled PNT for the hypersonic vehicle.

This SBIR topic seeks the development of non-GPS-based technology solutions for hypersonic vehicles that utilize systems taking advantage of alternate signals that enable precision navigation comparable to GPS, but without GPS in a GPS-denied environment. Such solutions include, but are not limited to

•  magnetometer aided navigation [Ref 5], 
• micro-electromechanical gyroscope for Inertial Navigation System (INS) [Ref 6],
• integrated optic inertial navigation system [Ref 7], 
• Electro-Optical/Infra-Red (EO/IR) imaging sensors [Ref 8], and so forth. 

The proposed solution can be a single system solution or an integrated system with the fusion of two orthogonal signal systems for improved PNT.

The proposed system solution should have minimized size, weight, and power (SWaP) compatible with current and future SWaP-constrained hypersonic vehicles. It should also be able to be sufficiently ruggedized to withstand harsh hypersonic high-velocity and high-g environmental and operating conditions. The system technologies should produce accuracy for the vehicle’s entire flight trajectory comparable to, or better than, current GPS technologies. The hypersonic vehicle’s terminal navigation success metrics are: 

• (a) a miss distance less than 5 m and a terminal speed of at least 1,700 m/s at the target; and 
• (b) navigation path constraints are satisfied while performing divert and evasive maneuvers to the target. 
• The hypersonic vehicle’s terminal phase begins at a distance of 200 km at an altitude of 25 km and a speed of 3,000 m/s.

The initial terminal hypersonic vehicle flight conditions are:

• (a) Range (km) min 200, max 200,
• (b) Azimuth min 10°, max 10°,
• (c) Heading Error min 10°, max 10°,
• (d) Altitude (km) min 24.8, max 25.2,
• (e) Speed (m/s) min 2,900, max 3,100,
• (f) Flight Path Angle min -5°, max 0°,
• (g) Angle of Attack min 1°, max 3°,
• (h) Bank Angle min 2°, max 2°,
• (i) Sideslip Angle min 2°, max 2°,
• (j) Crosswind Wind Speed (m/s) min 0, max 20,
• (k) Longitudinal Wind Speed (m/s) min 0, max 10, and
• (l) Atmospheric Density (kg/m³) min 1.293, max 1.210.

It is also required that the system should produce signals similar to GPS output codes. The system is also required to maintain compatibility with the DoD’s security, environmental, and other requirements for autonomous aviation navigation systems.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by 32 U.S.C. § 2004.20 et seq., National Industrial Security Program Executive Agent and Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence and Security Agency (DCSA) formerly Defense Security Service (DSS). The selected contractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances. This will allow contractor personnel to perform on advanced phases of this project as set forth by DCSA and NAVAIR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material during the advanced phases of this contract IAW the National Industrial Security Program Operating Manual (NISPOM), which can be found at Title 32, Part 2004.20 of the Code of Federal Regulations.

PHASE I: 

Develop PNT system concept solutions for use in hypersonic vehicles. Specify the signal systems for the proposed approach that will meet the specifications stated in the Description. Perform modeling and simulation and preliminary experimental demonstration to demonstrate the feasibility of the proposed design that will meet the required navigation success metrics in the Description in the hypersonic vehicle terminal phase. 

Simulations are to be run in three different scenarios to verify the effectiveness of the proposed navigation system.

1. In Scenario I, the noise conforms to the Gaussian distribution. 
2. In Scenario II, the pseudo range and pseudo range rate measurement information are interfered by pulses. 
3. In Scenario III, the navigation information is interrupted intermittently. 

The Phase I final report will detail all methods studied plus evidence of their feasibility on an aerial platform. The final report will also include an initial prototype design to be implemented in Phase II. All hardware and software requirements should be defined.

PHASE II: 

Develop a prototype based on the design of Phase I and demonstrate a navigation system based on the proposed signal systems. Evaluate, test, and validate the system’s feasibility to meet the project objective. The final test and evaluation of the system should be carried out under relevant operation conditions as close to hypersonic flight conditions as possible.

Work in Phase II may become classified. Please see note in Description paragraph.

PHASE III DUAL USE APPLICATIONS: 

Integrate and install the navigation system prototype onto a representative hypersonic vehicle for demonstration and evaluation in Advanced Naval Technology Exercise (ANTX) events.

As a new type of high-speed, large-range, and fast-response aircraft, the Airbreathing Hypersonic Vehicle (AHV) must not only cruise at high speed in the atmosphere, but also travel through the atmosphere as a space transportation vehicle. It has a wide range of applications in the military and civilian fields.

In the military field, its advantages are embodied in large combat airspace, wide range, fast flight speed, high maneuverability, strong penetration ability, flexible deployment and launch methods, high mission execution efficiency, large flight kinetic energy. Because it flies in the near space above 20 km altitude, which has low atmospheric density and low aerodynamic drag, it can effectively and quickly strike various long-range targets around the world. Meanwhile, it can shorten the enemy’s radar detection time and defense system response time. The above mentioned advantages determine that the hypersonic vehicle can be used as a long-range assault weapon launch platform or a direct strike weapon to efficiently complete various military tasks such as surveillance, reconnaissance, and strike operations.

In the civil field, the hypersonic vehicle can be used as a new type of intercontinental passenger/cargo transportation vehicle to improve human lifestyle and living standards. Hypersonic cargo vehicle can easily realize the rapid and accurate remote delivery of high-value materials, improve transportation efficiency, and stimulate global economic growth. Hypersonic passenger vehicles can shorten passenger travel time to improve work efficiency.

Hypersonic flight is attracting attention beyond civil aviation. The space industry is eyeing the technology to build craft that can take off like a plane, a development that could reduce the need for expensive rocket launches.

REFERENCES:

1. Chadwick, K.; Boyer, D. and Andre, S. "Plasma and flowfield induced effects on hypervelocity re-entry vehicles for L-band irradiation at near broadside aspect angles." 27th Plasma Dynamics and Lasers Conference 1996, p. 2322. https://doi.org/10.2514/6.1996-2322
   Copyright ©1996, American Institute of Aeronautics and Astronautics, Inc. AIAA Meeting Papers on Disc, June 1996 A9636686, F19628-94-C-0015, AIAA Paper 96-2322
   Abstract:
   A laboratory measurements program has been performed in the Calspan 96-in. hypersonic shock tunnel which has provided a database on the effects of an ionized flowfield about a re-entry vehicle on RF propagation. The plasma induced phase shift and attenuation for radar frequency propagations in the L-band were measured to multiple sensor locations on the test vehicle, at near broadside aspect angles, for selected vehicle orientations which include the effects of pitch and yaw (crossflow) on the measurements. Electron number density measurements were made by using swept-voltage thin-wire electrostatic probes in a rake over the various receiver stations on the blunt nose cone test vehicle. In addition, aerothermal measurements were made along both leeward and windward sides of the test vehicle at all configurations. The hypersonic test environment corresponded to high altitude (140 kft) re-entry conditions at 14,000 ft/sec. The simulations produce a laminar flow over the 3 foot long 7.8 degree cone half angle test vehicle.
   
   
2. Hartunian, R. A.; Stewart, G. E.; Fergason, S. D.; Curtiss, T. J. and Seibold, R. W. "Aerospace report no. ATR-2007(5309)-1: Causes and mitigation of radio frequency (RF) blackout during reentry of reusable launch vehicles." The Aerospace Corporation, 26 January 2007. https://rosap.ntl.bts.gov/view/dot/12493/dot_12493_DS1.pdf
   Abstract:
   The Aerospace Corporation was tasked to assess radio frequency (RF) blackout phenomena caused by plasma generation around vehicles during reentry and presently known methodologies for mitigation of this condition inhibiting communications. The purpose was to understand these phenomena and mitigation approaches applicable to reusable launch vehicles (RLVs) used for  commercial space. The viability and limitations of selecting frequency bands amenable to continuous communication in presence of plasma sheaths were assessed and mitigation recommendations provided.
   
   The ability to predict the ionized flow field for classes of vehicles most likely to emerge as hypersonic space transportation systems, with sufficient accuracy to identify the altitudes of blackout onset and recovery within reasonable bounds, has been demonstrated for altitudes greater than approximately 100 kft. This high-altitude regime is the most likely for future space transportation due to low g forces and low heat loads. For the lower, suborbital altitudes, many commercial RLVs will not be subjected to RF blackout because their relatively low velocities will  not create conditions that generate plasma.
   
   Determination of the interaction of RF with a known ionized layer, including reflection, attenuation, refraction, high-power breakdown limits, and also effects of the plasma on the antenna characteristics, have been demonstrated successfully. Analytic codes are available to evaluate these phenomena.
   
   Approaches for mitigating the interruption of communications due to interactions of plasma electrons with RF signals are reviewed. The most promising are: aerodynamic shaping, injection of quenchants, use of magnetic windows, and use of high frequencies
   
   
3. Blottner, F. G. "Viscous shock layer at the stagnation point with nonequilibrium air chemistry." AIAA Journal, 7(12), 1969, pp. 2281-2288. https://doi.org/10.2514/3.5528
   

   Abstract:
   A finite-difference method and a nonlinear overrelaxation method are investigated for solving the viscous shock layer at the stagnation point of a blunt body. An air gas model is employed with finite reaction rates and accurate thermodynamic and transport properties.
   
   For a body with a 1-in. nose radius and at a velocity of 20 kfps, the present results at 100, 150, 200, and 250 kft show that boundary-layer theory with the inviscid edge flow in chemical equilibrium is appropriate for some altitude below 150 kft. When the altitude is 250 kft, the effects of shock slip must be included in the viscous shock-layer solution. For this case, the air is only slightly dissociated and ionized. The present results, with a seven-species air model, are in general agreement with the diatomic air model results of Cheng and Chung.

4. Hartunian, R.; Stewart, G.; Curtiss, T.; Fergason, S.; Seibold, R. and Shome, P. "Implications and mitigation of radio frequency blackout during reentry of reusable launch vehicles." AIAA Atmospheric Flight Mechanics Conference and Exhibit, August 2007, p. 6633. https://www.researchgate.net/profile/Pradipta-Shome/publication/201661529_Implications_and_Mitigation_of_RF_Blackout_during_Reentry_of_RLVs/links/0912f5061ece018f3f000000/Implications-and-Mitigation-of-RF-Blackout-during-Reentry-of-RLVs.pdf
   
   Abstract:
   

   Reentering hypersonic vehicles become surrounded by a layer of dissociated plasma, consisting of ions and free electrons, during high-velocity passage through the upper atmosphere. The ionized layer or sheath can reflect and attenuate propagating electromagnetic waves severely, causing radio communications to be degraded or temporarily disrupted. This interruption in signal transmission and reception, or radio frequency (RF) blackout, is of concern for determination of vehicle position and vehicle control, key issues affecting public safety, especially for future manned flights where continuous contact with ground control will be crucial.
   
   Causes of RF blackout from plasma generation around vehicles during hypersonic reentry were reviewed. Methodologies for mitigating communications blackouts, applicable to reusable launch vehicles (RLVs) for commercial space, were surveyed. Interactions of RF signals with a known ionized layer, including reflection, attenuation, refraction, high-power breakdown limits, and effects of the plasma on antenna characteristics, were explored.
   
   RF blackout mitigation strategies fall into two general classes: passive and active. Passive approaches necessitate design of vehicle configurations to minimize plasma effects on communications signals. Active approaches entail manipulation of the plasma conditions and electron density in localized regions surrounding communication antennas to facilitate RF transmission.
   
   Examples of passive approaches include: using vehicles with leading edges aerodynamically shaped to minimize plasma generation, designing for communication at higher frequencies, and designing for radiating higher power from the vehicle. Examples of active approaches include: injection of electrophilic quenchants or droplets that evaporatively cool the plasma and application of magnetic fields. The most promising approaches for mitigating the interruption of communications due to interactions of plasma electrons with RF signals are aerodynamic shaping, injection of electrophilic quenchants, use of magnetic windows, and use of high frequencies within the limits imposed by atmospheric attenuation.

5. Won, D.; Ahn, J.; Sung, S.; Heo, M.; Im, S. H. and Lee, Y. J. "Performance improvement of inertial navigation system by using magnetometer with vehicle dynamic constraints." Journal of Sensors, 2015. https://www.hindawi.com/journals/js/2015/435062/
   

   Abstract

   A navigation algorithm is proposed to increase the inertial navigation performance of a ground vehicle using magnetic measurements and dynamic constraints. The navigation solutions are estimated based on inertial measurements such as acceleration and angular velocity measurements. To improve the inertial navigation performance, a three-axis magnetometer is used to provide the heading angle, and nonholonomic constraints (NHCs) are introduced to increase the correlation between the velocity and the attitude equation. The NHCs provide a velocity feedback to the attitude, which makes the navigation solution more robust. Additionally, an acceleration-based roll and pitch estimation is applied to decrease the drift when the acceleration is within certain boundaries. The magnetometer and NHCs are combined with an extended Kalman filter. An experimental test was conducted to verify the proposed method, and a comprehensive analysis of the performance in terms of the position, velocity, and attitude showed that the navigation performance could be improved by using the magnetometer and NHCs. Moreover, the proposed method could improve the estimation performance for the position, velocity, and attitude without any additional hardware except an inertial sensor and magnetometer. Therefore, this method would be effective for ground vehicles, indoor navigation, mobile robots, vehicle navigation in urban canyons, or navigation in any global navigation satellite system-denied environment.

6. Kou, Z.; Liu, J.; Cao, H.; Feng, H.; Ren, J.; Kang, Q. and Shi, Y. "Design and fabrication of a novel MEMS vibrating ring gyroscope." 2017 IEEE 3rd Information Technology and Mechatronics Engineering Conference (ITOEC), October 2017, pp. 131-134. https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8122396&casa_token=eLEE3s41mPEAAAAA:equlN_ObC-kelo7CdcfIHNvIwtkrP6ZR7fIaHB7otu_7z5r5iGMTs3vy3Z2HJTQ9k1Sx3OK1&tag=1
7. Dell'Olio, F.; Ciminelli, C.; Armenise, M. N.; Soares, F. M. and Rehbein, W. "Design, fabrication, and preliminary test results of a new InGaAsP/InP high-Q ring resonator for gyro applications." 2012 International Conference on Indium Phosphide and Related Materials, August 2012, pp. 124-127. IEEE. https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6403336&casa_token=I9OstnMZItYAAAAA:2QEJ8zsBYX8KyE66DPXO998Q-dO8UpvtLMRteNXGQg6cpec0AOc57PbaPYQ53znXvB1OItAG
8. Wood, B.; Irvine, N.; Schacher, G. and Jensen, J. "Joint Multi-Mission Electro-Optic System (JMMES) report of military utility." Naval Postgraduate School, Monterey, California, 2010. https://core.ac.uk/download/pdf/36694417.pdf
9. "National Industrial Security Program Executive Agent and Operating Manual (NISP), 32 U.S.C. § 2004.20 et seq." Code of Federal Regulations, 1993. https://www.ecfr.gov/current/title-32/subtitle-B/chapter-XX/part-2004

KEYWORDS: Hypersonic; missile; navigation; terminal; guidance; global position system (GPS)

TPOC-1: Richard LaMarca

Phone: (301) 342-3728

TPOC-2: Chandraika (John) Sugrim 

Phone: (904) 460-4494

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** TOPIC NOTICE **

The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 24.2 SBIR BAA. Please see the official DoD Topic website at www.defensesbirsttr.mil/SBIR-STTR/Opportunities/#announcements for any updates. The DoD issued its Navy 24.2 SBIR Topics pre-release on April 17, 2024 which opens to receive proposals on May 15, 2024, and closes June 12, 2024 (12:00pm ET). Direct Contact with Topic Authors: During the pre-release period (April 17, through May 14, 2024) proposing firms have an opportunity to directly contact the Technical Point of Contact (TPOC) to ask technical questions about the specific BAA topic. Once DoD begins accepting proposals on May 15, 2024 no further direct contact between proposers and topic authors is allowed unless the Topic Author is responding to a question submitted during the Pre-release period. Topics Search Engine: Visit the DoD Topic Search Tool at www.dodsbirsttr.mil/topics-app/ to find topics by keyword across all DoD Components participating in this BAA. Help: If you have general questions about the DoD SBIR program, please contact the DoD SBIR Help Desk via email at DoDSBIRSupport@reisystems.com

additional sources

Helicon Source for Development of a Re-Entry Blackout Amelioration

Lemmer, K.M. (2009). Use of a Helicon Source for Development of a Re-Entry Blackout Amelioration System (Doctoral dissertation, University of Michigan). Retrieved from [https://www.researchgate.net/publication/30864311_Use_of_a_Helicon_Source_for_Development_of_a_Re-Entry_Blackout_Amelioration_System]

Here is a summary of the main points of the research presented in this dissertation:

1. Development of a helicon plasma source to simulate the plasma densities encountered during atmospheric re-entry. The helicon source was capable of producing plasma densities representative of those found at altitudes ranging from 60-80 km.
2. Design and testing of a plasma mitigation system called ReComm that utilized crossed electric and magnetic fields (E x B) to reduce the plasma density. The system consisted of an electromagnet and two electrodes.
3. Characterization of the plasma properties downstream of the helicon source using Langmuir probes, a retarding potential analyzer, and a residual gas analyzer. Key parameters measured include ion density, electron temperature, plasma potential, and ion energy distribution.
4. Evaluation of the ReComm system's ability to reduce plasma density using Langmuir probes, a hairpin resonance probe, and a signal attenuation probe. Density reductions up to 80% were observed depending on the magnetic field strength and electrode voltage.
5. Discovery that the magnetic field alone caused significant density reduction, likely due to the diverging field geometry produced by the electromagnet design. This was confirmed using particle tracing simulations in COMSOL.
6. Comparison of experimental results to computational fluid dynamics simulations of the ReComm system. General trends agreed, but the simulations overpredicted the effect of the electric field.

In summary, this research demonstrated the feasibility of using E x B fields to mitigate plasma density in conditions representative of atmospheric re-entry, but also highlighted the importance of magnetic field topology in the mitigation mechanism.

Electron Density

The helicon plasma source was able to produce electron densities representative of those found during atmospheric re-entry at altitudes ranging from 60 to 80 km. Specifically:

1. With an empty vacuum chamber downstream of the helicon source, the electron densities ranged from 1.7 × 10^17 m^-3 to 3.3 × 10^17 m^-3. These values are similar to those encountered at altitudes between 60 and 70 km during re-entry.
2. When the ReComm system was placed downstream of the helicon source (but not operating), the electron densities ranged from 5.0 × 10^16 m^-3 to 1.3 × 10^17 m^-3. These values are representative of the densities found at altitudes between 70 and 80 km during re-entry.

The density of the plasma layer was controlled by adjusting the operating parameters of the helicon source:

1. Input power: Higher input power to the RF antenna resulted in higher plasma densities.
2. Magnetic field strength: Increasing the magnetic field strength of the helicon source electromagnets led to higher plasma densities.
3. Gas flow rate: The gas flow rate into the vacuum chamber was adjusted to maintain a constant pressure of 0.6 ± 0.05 mtorr. This pressure was chosen to achieve the desired plasma densities while ensuring stable operation of the helicon source.

By tuning these parameters, the researcher was able to produce plasma densities that simulated different altitudes during atmospheric re-entry. The presence of the ReComm system downstream also affected the plasma density, likely due to the additional surface area for plasma recombination.

ReComm (Re-entry and hypersonic vehicle plasma Communication) system

The ReComm (Re-entry and hypersonic vehicle plasma Communication) system was designed to mitigate the plasma density in conditions representative of atmospheric re-entry. The system consisted of two main components:

• 1. Electromagnet: A custom-designed, water-cooled electromagnet created a strong, non-uniform magnetic field (up to 2000 G) in the region downstream of the helicon plasma source. The magnet was made of copper tubing wrapped around an iron core and base to enhance the field strength and uniformity.
• 2. Electrodes: Two 0.32-cm-diameter stainless steel electrodes were placed in the plasma, perpendicular to the magnetic field lines. The electrode closer to the helicon source (anode) was grounded, while the downstream electrode (cathode) was biased to a negative potential (0 to -250 V). The electrodes were embedded in a mica sheet, which served as a dielectric barrier and simulated the surface of a re-entry vehicle.

ReComm system effectiveness

The effectiveness of the ReComm system in reducing the electron density was measured using three diagnostic tools:

• 1. Langmuir probes: A commercial RF-compensated Langmuir probe was used to measure the electron density downstream of the ReComm system. By comparing the density with and without the ReComm system operating, the percentage reduction in density was calculated.
• 2. Hairpin resonance probe: This probe, consisting of a U-shaped wire, was used to measure the plasma frequency, which is directly related to the electron density. Changes in the plasma frequency with the ReComm system operating provided another measure of density reduction.
• 3. Signal attenuation (S2-1) probe: This diagnostic consisted of two antennas separated by a short distance. A network analyzer was used to transmit a signal from one antenna and measure the attenuation of the signal received by the other antenna. The attenuation is related to the electron density between the antennas, providing a third method to quantify the ReComm system's effectiveness.

By comparing the measurements from these diagnostics with the ReComm system on and off, the researcher was able to quantify the reduction in electron density under various magnetic field strengths and electrode voltages. The results showed density reductions up to 80%, with the magnetic field being the dominant factor in the mitigation process. 

Scaling Up the Design

The dissertation does not provide experimental data on the performance of the ReComm system with magnetic fields measured in Tesla. However, we can extrapolate the potential effects of higher magnetic fields based on the observed trends and the underlying physics.

In the experiments, the maximum magnetic field strength tested was 2000 G, or 0.2 T. The results showed that increasing the magnetic field strength led to greater reductions in the electron density. For example, at z = -75 mm, the density reduction increased from 35% at 925 G (0.0925 T) to 70% at 1850 G (0.185 T) with no voltage applied to the electrodes.

If the magnetic field strength were increased to the order of 1 Tesla or higher, we might expect:

1. Further reduction in electron density: The stronger magnetic field would more effectively confine the electrons, preventing them from reaching the region where an antenna would be located. This could lead to even higher density reductions, potentially exceeding the 80% observed in the experiments.
2. Increased influence of the magnetic field topology: The non-uniformity and divergence of the magnetic field played a significant role in the density reduction mechanism. With higher magnetic fields, these effects could become even more pronounced, making the field topology a critical factor in the ReComm system's performance.
3. Reduced impact of the electric field: In the experiments, the electric field had a limited effect on the density reduction compared to the magnetic field. At higher magnetic field strengths, the relative importance of the electric field might further diminish, as the electron dynamics would be primarily governed by the strong magnetic field.

However, it is important to note that increasing the magnetic field strength would also present practical challenges, such as increased power consumption, cooling requirements, and potential impact on the spacecraft systems. Additionally, the plasma confinement and density reduction mechanisms might become more complex at higher magnetic fields, requiring further experimental and computational studies to fully understand and optimize the ReComm system's performance.