Design principles and algorithm development for two types of NextGen airborne conflict detection and collision avoidance

Abstract

As the aviation community moves toward the Next Generation Air Transportation System (NextGen), the current Traffic Alert and Collision Avoidance System (TCAS II) may become inadequate. This paper describes two types of algorithms that use Automatic Dependent Surveillance-Broadcast (ADS-B) as the surveillance source for future airborne collision avoidance systems (CASs). The first type, denoted by NextCAS I, estimates the range, range rate, altitude and altitude rate from the ADS-B state vector information but maintains much of the detection and all of the resolution logic structure of the current TCAS. The second type, denoted by NextCAS II, provides a novel approach to detection and resolution of air traffic conflicts in the 3-dimensional (3-D) airspace between two aircraft. The inputs to the detection algorithm are the current 3-D position and speed vector of both aircraft and a cylindrical minimum safety protection zone (PZ) around the conflicting aircraft. For a CAS, the size of the configurable PZ can be assigned values that the Federal Aviation Administration (FAA) considers as a near mid-air collision (NMAC 1 ) incident. When available, additional inputs, such as measurement uncertainties and intruder type (e.g., manned/unmanned), can be used to alter the default protection zone. The conflict detection takes into account the 3-D encounter (e.g., closure rate, miss distance, relative converging maneuver). The resolution algorithm initially computes a set of six resolution advisories (RAs) and associated resolution alert times that ensure no violation of the protection zone. The six resolutions consist of three sets of two maneuvers related to: ground track (left, right), forward speed (speed up, slow down), and vertical speed (climb, descend). The 1 NMAC -The NMAC is defined by a cylindrical volume with a radius of 500 ft and a height of 200 ft, centered on each aircraft. initial solutions take into account ownship capability (i.e., max climb/descent rate, max turn rate, max speed/stall speed) and ownship pilot response delay (e.g., autonomous vs. manual RA execution). These six solutions are subsequently down-selected in two steps: first, based on the encounter geometry, a single implicitly coordinated, independent solution is selected for each of the three dimensions; then, based on ownship preferences and operational considerations, a final RA solution is selected.

4D Trajectory Optimization of Commercial Flight for Green Civil Aviation

“…In the international standard atmosphere (ISA) model of BADA, ISA temperature gradient with the altitude below the tropopause is β = −0.0065 (K/m) and the ISA temperature of the standard sea level is T 0 = 288.15 (K). The altitude of the tropopause is h trop = 11, 000 (m) in the ISA model and the temperature is considered constant above the tropopause: (16) where T trop is the temperature of the tropopause (K). The pressure is calculated using the following formula: (17) Finally, the air density is calculated from the pressure and the temperature at altitude using the perfect gas law:…”

“…In the research of trajectory optimization of commercial flight, an aircraft point-mass model was proposed between the six degrees of freedom model and the basic kinematics model, which is considered to be a sufficiently accurate dynamic method for aircraft trajectory planning research [15]. Based on the basic model, Chamlou proposed a new 3-dimensional trajectory collision detection algorithm for judging aircraft position and velocity through ADS-B data and TCAS system [16]. Mou and Wang used the AP model and the GAP model to establish the matrix corresponding to the aircraft and the flight level, so as to obtain the optimal efficiency value of the flight level change scheme through the Hungarian algorithm [17].…”

Quasi-ADS-B Based UAV Conflict Detection and Resolution to Manned Aircraft

“…The broadcasting data packet is designed following the standard CPR format in ADS-B plus the following data with next waypoint in flight [6,7,14,15]. The standard CPR (Compact Position Reporting) will be useful to be capable of merging and integrating the UAV/CD&R system with other systems using Quasi-ADS-B.…”

“…The avoidance path is calculated by the possible turning angle to decrease of overlapping ratio at most. With some restrict parameters by turning radius in constant speed, a safe right turn trajectory can be plotted to assist the pilot for conducting conflict avoidance [14,15].…”

Airplane positioning using airborne collision avoidance system data

“…Disadvantages of ACAS II and the constant increase of airspace capacity combined with the problems of integrating unmanned aerial vehicles in controlled air traffic [5] have led to finding ways to improve ACAS standard. The proposed ACAS X concept is based on the probabilistic approach with the use of dynamic programming for choosing the optimal maneuvering path [1,6,7]. Surveillance of ACAS X is improved by using data from the Automatic Dependent Surveillance-Broadcast (ADS-B).…”