Abstract
The integration of Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) for Urban Air Mobility (UAM) operations will create the need to develop robust, efficient, and verifiable tools and techniques for UAS Traffic Management (UTM). In this paper, we present a novel approach for strategic detection and resolution of airborne conflicts using Satisfiability Modulo Theories (SMT) solvers. Our approach takes a flight plan for an ownship, a set of immutable flight plans for traffic aircraft, and a set of constraints, and then returns a flight plan for the ownship that satisfies all constraints and is also conflict free with respect to the traffic aircraft. The constraints can relate to operational, business, or other aspects which must be considered while setting up the conflict resolution task as a constraint satisfaction problem. We present simulations of our approach using a prototype implementation based on \(\textsf {dReal}\), an SMT solver that is specialized for solving non-linear real function problems, showing promising results.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
Notes
- 1.
Other SMT solvers, such as Z3 [7], which support non-linear arithmetic, do not fully support trigonometric functions, which is needed for this work.
- 2.
We use the definition of [31] where \(\bar{F_o}\) has the same spatial configuration as \({F_o}\).
- 3.
This problem statement aligns well with the discovery and synchronization service (DSS) based concept of operation for UAM where a provider of services for UAM (PSU) has to prove awareness of other PSUs with active operations in an area for its proposed operation to be accepted by the DSS of that area [6].
- 4.
These constraints can also take into account factors like the aerodynamic capabilities of the ownship (e.g., fixed wing vs rotorcraft, flight-surface damage, etc.).
- 5.
In this paper, the solution space is finite and bounded by a set of discrete ground speeds allowed for the ownship (see Sect. 2.1).
- 6.
Depending on the use case, the constraints can be adjusted accordingly.
- 7.
For simplicity, in this paper we assume the absence of wind. However, more complicated constraints may be designed by factoring in wind.
References
Alejo, D., Cobano, J.A., Heredia, G., Ollero, A.: Collision-free 4D trajectory planning in unmanned aerial vehicles for assembly and structure construction. J. Intell. Robot. Syst. 73(1), 783–795 (2014)
Ayhan, S., Costas, P., Samet, H.: Prescriptive analytics system for long-range aircraft conflict detection and resolution. In: Proceedings of the 26th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, pp. 239–248 (2018)
Balachandran, S., Manderino, C., Muñoz, C., Consiglio, M.: A decentralized framework to support UAS merging and spacing operations in urban canyons. In: 2020 International Conference on Unmanned Aircraft Systems (ICUAS), pp. 204–210. IEEE (2020)
Clarke, E., Grumberg, O., Jha, S., Lu, Y., Veith, H.: Counterexample-guided abstraction refinement. In: Emerson, E.A., Sistla, A.P. (eds.) CAV 2000. LNCS, vol. 1855, pp. 154–169. Springer, Heidelberg (2000). https://doi.org/10.1007/10722167_15
Colbert, B.K., Slagel, J.T., Crespo, L.G., Balachandran, S., Munoz, C.: Polysafe: a formally verified algorithm for conflict detection on a polynomial airspace. IFAC-PapersOnLine 53(2), 15615–15620 (2020)
Craven, N., et al.: Report: X3 Simulation with National Campaign-Developmental Test (NC-DT) Airspace Partners. Technical report, National Aeronatics and Space Administration (2021). https://aviationsystems.arc.nasa.gov/publications/2021/NASA-TM-20210011098.pdf. Accessed 25 June 2021
de Moura, L., Bjørner, N.: Z3: an efficient SMT solver. In: Ramakrishnan, C.R., Rehof, J. (eds.) TACAS 2008. LNCS, vol. 4963, pp. 337–340. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-78800-3_24
Dowek, G., Munoz, C., Carreño, V.: Provably safe coordinated strategy for distributed conflict resolution. In: AIAA Guidance, Navigation, and Control Conference and Exhibit, p. 6047 (2005)
Dowek, G., Munoz, C., Geser, A.: Tactical conflict detection and resolution in a 3-d airspace. Technical report INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA (2001)
Durand, N., Alliot, J.M., Noailles, J.: Automatic aircraft conflict resolution using genetic algorithms. In: Proceedings of the 1996 ACM Symposium on Applied Computing, pp. 289–298 (1996)
Ekici, B., et al.: SMTCoq: a plug-in for integrating SMT solvers into Coq. In: Majumdar, R., Kunčak, V. (eds.) CAV 2017. LNCS, vol. 10427, pp. 126–133. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-63390-9_7
Galdino, A.L., Muñoz, C., Ayala-Rincón, M.: Formal verification of an optimal air traffic conflict resolution and recovery algorithm. In: Leivant, D., de Queiroz, R. (eds.) WoLLIC 2007. LNCS, vol. 4576, pp. 177–188. Springer, Heidelberg (2007). https://doi.org/10.1007/978-3-540-73445-1_13
Gao, S., Kong, S., Clarke, E.M.: dReal: an SMT solver for nonlinear theories over the reals. In: Bonacina, M.P. (ed.) CADE 2013. LNCS (LNAI), vol. 7898, pp. 208–214. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-38574-2_14
Irfan, A., et al.: Towards verification of neural networks for small unmanned aircraft collision avoidance. In: 2020 AIAA/IEEE 39th Digital Avionics Systems Conference (DASC), pp. 1–10. IEEE (2020)
Katz, G., Barrett, C., Tinelli, C., Reynolds, A., Hadarean, L.: Lazy proofs for DPLL (T)-based SMT solvers. In: 2016 Formal Methods in Computer-Aided Design (FMCAD), pp. 93–100. IEEE (2016)
Krozel, J., Peters, M., Bilimoria, K.D., Lee, C., Mitchell, J.S.: System performance characteristics of centralized and decentralized air traffic separation strategies. Air Traffic Control Q. 9(4), 311–332 (2001)
Li, M., et al.: Requirements-based automated test generation for safety critical software. In: 2019 IEEE/AIAA 38th Digital Avionics Systems Conference (DASC), pp. 1–10. IEEE (2019)
Liang, T., Reynolds, A., Tinelli, C., Barrett, C., Deters, M.: A DPLL(T) theory solver for a theory of strings and regular expressions. In: Biere, A., Bloem, R. (eds.) CAV 2014. LNCS, vol. 8559, pp. 646–662. Springer, Cham (2014). https://doi.org/10.1007/978-3-319-08867-9_43
Meng, B., et al.: Towards a correct-by-construction design of integrated modular avionics. In: Conference on Formal Methods in Computer-Aided Design – FMCAD, p. 221 (2023)
Meng, B., et al.: Verdict: a language and framework for engineering cyber resilient and safe system. Systems 9(1), 18 (2021)
Meng, B., Reynolds, A., Tinelli, C., Barrett, C.: Relational constraint solving in SMT. In: de Moura, L. (ed.) CADE 2017. LNCS (LNAI), vol. 10395, pp. 148–165. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-63046-5_10
Meng, B., Viswanathan, A., Smith, W., Moitra, A., Siu, K., Durling, M.: Synthesis of optimal defenses for system architecture design model in MaXSMT. In: Deshmukh, J.V., Havelund, K., Perez, I. (eds.) NFM 2022. LNCS, vol. 13260, pp. 752–770. Springer, Cham (2022). https://doi.org/10.1007/978-3-031-06773-0_40
Munoz, C., Narkawicz, A., Chamberlain, J.: A TCAS-ii resolution advisory detection algorithm. In: AIAA Guidance, Navigation, and Control (GNC) Conference, p. 4622 (2013)
Murrieta-Mendoza, A., Botez, R.M., Patrón, R.S.F.: Flight altitude optimization using genetic algorithms considering climb and descent costs in cruise with flight plan information. Technical report SAE Technical Paper (2015)
Narkawicz, A., Muñoz, C., Dutle, A.: Sensor uncertainty mitigation and dynamic well clear volumes in DAIDALUS. In: 2018 IEEE/AIAA 37th Digital Avionics Systems Conference (DASC), pp. 1–8. IEEE (2018)
National Aeronatics and Space Administration: Range and Fuel Consumption Activity. https://www.grc.nasa.gov/www/k-12/BGP/Devon/range_fuel_act.htm. Accessed 18 June 2021
Paul, S.: Emergency Trajectory Generation for Fixed-Wing Aircraft. Master’s thesis, Rensselaer Polytechnic Institute (2018)
Paul, S., Agha, G.A., Patterson, S., Varela, C.A.: Verification of eventual consensus in synod using a failure-aware actor model. In: Dutle, A., Moscato, M.M., Titolo, L., Muñoz, C.A., Perez, I. (eds.) NFM 2021. LNCS, vol. 12673, pp. 249–267. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-76384-8_16
Paul, S., et al.: Formal verification of safety-critical aerospace systems. IEEE Aerosp. Electron. Syst. Mag. 38(5), 72–88 (2023). https://doi.org/10.1109/MAES.2023.3238378
Paul, S., Hole, F., Zytek, A., Varela, C.A.: Wind-aware trajectory planning for fixed-wing aircraft in loss of thrust emergencies. In: 2018 IEEE/AIAA 37th Digital Avionics Systems Conference (DASC), pp. 1–10 (2018).https://doi.org/10.1109/DASC.2018.8569842
Paul, S., Patterson, S., Varela, C.A.: Conflict-aware flight planning for avoiding near mid-air collisions. In: The 38th AIAA/IEEE Digital Avionics Systems Conference (DASC 2019). San Diego, CA (2019).https://doi.org/10.1109/DASC43569.2019.9081658
Peters, A., Balachandran, S., Duffy, B., Smalling, K., Consiglio, M., Muñoz, C.: Flight test results of a distributed merging algorithm for autonomous UAS operations. In: 2020 AIAA/IEEE 39th Digital Avionics Systems Conference (DASC), pp. 1–7. IEEE (2020)
Pritchett, A.R., Genton, A.: Negotiated decentralized aircraft conflict resolution. IEEE Trans. Intell. Transp. Syst. 19(1), 81–91 (2017)
Reynolds, A., Iosif, R., Serban, C., King, T.: A decision procedure for separation logic in SMT. In: Artho, C., Legay, A., Peled, D. (eds.) ATVA 2016. LNCS, vol. 9938, pp. 244–261. Springer, Cham (2016). https://doi.org/10.1007/978-3-319-46520-3_16
Sacharny, D., Henderson, T.C.: A lane-based approach for large-scale strategic conflict management for UAS service suppliers. In: 2019 International Conference on Unmanned Aircraft Systems (ICUAS), pp. 937–945. IEEE (2019)
Shone, R., Glazebrook, K., Zografos, K.G.: Applications of stochastic modeling in air traffic management: methods, challenges and opportunities for solving air traffic problems under uncertainty. Eur. J. Oper. Res. (2020)
Siu, K., et al.: Architectural and behavioral analysis for cyber security. In: 2019 IEEE/AIAA 38th Digital Avionics Systems Conference (DASC), pp. 1–10. IEEE (2019)
Yang, Y., Zhang, J., Cai, K.Q., Prandini, M.: Multi-aircraft conflict detection and resolution based on probabilistic reach sets. IEEE Trans. Control Syst. Technol. 25(1), 309–316 (2016)
Young-Brown, F.: FUEL BURN RATES FOR PRIVATE AIRCRAFT (2015). https://www.sherpareport.com/aircraft/fuel-burn-private-aircraft.html. Accessed 18 June 2021
Zhang, Y.J., Malikopoulos, A.A., Cassandras, C.G.: Optimal control and coordination of connected and automated vehicles at urban traffic intersections. In: 2016 American Control Conference (ACC), pp. 6227–6232. IEEE (2016)
Acknowledgement
The authors would like to thank GE Aerospace Research for supporting the work and the reviewers of NFM 2024 for their detailed and constructive comments that helped improve the final manuscript.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2024 The Author(s), under exclusive license to Springer Nature Switzerland AG
About this paper
Cite this paper
Paul, S., Meng, B., Alexander, C. (2024). SMT-Based Aircraft Conflict Detection and Resolution. In: Benz, N., Gopinath, D., Shi, N. (eds) NASA Formal Methods. NFM 2024. Lecture Notes in Computer Science, vol 14627. Springer, Cham. https://doi.org/10.1007/978-3-031-60698-4_11
Download citation
DOI: https://doi.org/10.1007/978-3-031-60698-4_11
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-031-60697-7
Online ISBN: 978-3-031-60698-4
eBook Packages: Computer ScienceComputer Science (R0)