A Family of Well-Clear Boundary Models for the Integration of UAS in the NAS

Muñoz, César; Narkawicz, Anthony; Chamberlain, James P.; Consiglio, Maria; Upchurch, Jason M.

doi:10.2514/6.2014-2412

Cited by 41 publications

(31 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With risk as the primary evaluation metric, we considered many different mathematical forms of well clear. Formally, well clear could be defined as any combination of spatial components [4]: horizontal separation r, vertical separation Δh, or temporal components [5,6] τ, τ mod , and distance modification (DMOD). DMOD is spatial threshold used to control the behavior of τ mod to account for specific types of encounters, such as slow closure encounters, and τ mod is a temporal variable defined as the modified time till closest point of approach (CPA):…”

Section: A Well-clear Forms and Risk Thresholdmentioning

confidence: 99%

See 1 more Smart Citation

Well-Clear Recommendation for Small Unmanned Aircraft Systems Based on Unmitigated Collision Risk

Weinert

Campbell

Vela

et al. 2018

Journal of Air Transportation

View full text Add to dashboard Cite

Unmanned aircraft systems must demonstrate a capability to sense and avoid air traffic as part of a layered conflict management system to enable safe operations in the National Airspace System. During operations, an unmanned aircraft system should attempt to remain "well clear" to minimize the need for a collision avoidance action. Previously, a well-clear definition was adopted for large unmanned aircraft systems; however, this definition is not appropriate for small unmanned aircraft system weighing less than 55 lb operating at low altitudes. In response, this paper outlines research toward a definition of well clear for small unmanned aircraft systems, based on airborne collision risk, for midterm concepts of operations at low altitudes in nonterminal airspace.

show abstract

Section: A Well-clear Forms and Risk Thresholdmentioning

confidence: 99%

“…Well clear, defined with these components, is mathematically symmetric, where both the UAS and manned aircraft have the same perception of the UAS being in well clear or not [6]. We did not assume or give preference to any specific well-clear form.…”

Section: A Well-clear Forms and Risk Thresholdmentioning

confidence: 99%

Well-Clear Recommendation for Small Unmanned Aircraft Systems Based on Unmitigated Collision Risk

Weinert

Campbell

Vela

et al. 2018

Journal of Air Transportation

View full text Add to dashboard Cite

show abstract

“…For arbitrary values of DMOD, ZTHR, TAUMOD, and TCOA, with HMD = DMOD, Formula (1) satisfies several operational requirements [6]. The values of these thresholds recommended by the UAS SARP [2] and adopted by the RTCA SC-228 are DMOD = HMD = 4000ft, ZTHR = 450ft, TAUMOD = 35s, and TCOA = 0s.…”

Section: Well-clear Boundary and Its Extensionsmentioning

confidence: 99%

“…Both τ mod and τ are approximations of time to closest point of approach, t cpa . Indeed, it has been formally proven that for horizontally converging trajectories whose initial states are outside DMOD, i.e., s · v < 0, s > DMOD, and [6]. In contrast to t cpa , the computations of τ and τ mod can be done without directional information.…”

Section: Well-clear Boundary and Its Extensionsmentioning

confidence: 99%

Formal Analysis of Extended Well-Clear Boundaries for Unmanned Aircraft

Muñoz

Narkawicz

2016

Lecture Notes in Computer Science

Self Cite

View full text Add to dashboard Cite

This paper concerns the application of formal methods to the definition of a detect and avoid concept for unmanned aircraft systems (UAS). In particular, it illustrates how formal analysis was used to explain and correct unexpected behaviors of the logic that issues alerts when two aircraft are predicted not to be well clear from one another. As a result of this analysis, a recommendation was proposed to, and subsequently adopted by, the US standards organization that defines the minimum operational requirements for the UAS detect and avoid concept.

show abstract

“…In the absence of an onboard pilot to make a determination of being well clear, the need for an unambiguous, quantitative definition has been identified [12][13][14][15][16][17][18]. Additionally, the need for compatibility/interoperability between existing airborne collision avoidance systems (ACAS) and future UAS SAA functionality is a well-established problem concerning the integration of UAS into civil airspace [1,[14][15][16][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Characterizing the Effects of a Vertical Time Threshold for a Class of Well-Clear Definitions

Upchurch

Muñoz

Narkawicz

et al. 2015

Air Traffic Control Quarterly

Self Cite

View full text Add to dashboard Cite

A fundamental requirement for the integration of unmanned aircraft into civil airspace is the capability of aircraft to remain well clear of each other and avoid collisions. This requirement has led to a broad recognition of the need for an unambiguous, formal definition of well clear. It is further recognized that any such definition must be interoperable with existing airborne collision avoidance systems (ACAS). A particular class of well-clear definitions uses logic checks of independent distance thresholds as well as independent time thresholds in the vertical and horizontal dimensions to determine if a wellclear violation is predicted to occur within a given time interval. Existing ACAS systems also use independent distance thresholds, however a common time threshold is used for the vertical and horizontal logic checks. The main contribution of this paper is the characterization of the effects of the decoupled vertical time threshold on a well-clear definition in terms of (1) time to wellclear violation, and (2) interoperability with existing ACAS. The paper provides governing equations for both metrics and includes simulation results to illustrate the relationships. In this paper, interoperability implies that the time of well-clear violation is strictly less than the time a resolution advisory is issued by ACAS. The encounter geometries under consideration in this paper are initially well clear and consist of constant-velocity trajectories resulting in near-mid-air collisions.

show abstract

A Family of Well-Clear Boundary Models for the Integration of UAS in the NAS

Cited by 41 publications

References 4 publications

Well-Clear Recommendation for Small Unmanned Aircraft Systems Based on Unmitigated Collision Risk

Well-Clear Recommendation for Small Unmanned Aircraft Systems Based on Unmitigated Collision Risk

Formal Analysis of Extended Well-Clear Boundaries for Unmanned Aircraft

Characterizing the Effects of a Vertical Time Threshold for a Class of Well-Clear Definitions

Contact Info

Product

Resources

About