Integrating Runtime Verification into an
Automated UAS Traffic Management System

Matthew Cauwels, Abigail Hammer, Benjamin Hertz, Phillip H. Jones, Kristin Y. Rozier

This webpage contains supplementary specifications for "Integrating Runtime Verification into an
Automated UAS Traffic Management System" by M. Cauwels, A. Hammer, B. Hertz, P. H. Jones, and K. Y. Rozier

SB_UTM_5

Specification Description

The latitude (fpLat) of any UAS's waypoint in its flight plan will be bounded between MaxLatLB and MinLatUB.

Signals Required

fpLat

Boolean Conversion of Signals to Atomic Inputs 

fpLat_leq_MaxLatUB = 1;
for(i = 0; i < NumUAS; i++)
{
    for(j = 0; j < NumWP[i]; j++)
    {
        // if UAS i's fpLat is greater than the upper bounded
        // and the value is not "nan"
        if((fpLat[i] > MaxLatUB) && (fpLat[i] == fpLat[i])
        { 
            wpLat_leq_MaxLatUB = 0;
        }
    }
} 
fpLat_geq_MinLatLB = 1;
for(i = 0; i < NumUAS; i++)
{
    for(j = 0; j < NumWP[i]; j++)
    {
        // if UAS i's fpLat is less than the lower bounded
        // and the value is not "nan"
        if((fpLat[i] < MinLatLB) && (fpLat[i] == fpLat[i])
        { 
            fpLat_geq_MinLatLB = 0;
        }
    }
}

MLTL Specification

Original: (fpLat_leq_MaxLatUB ∧ fpLat_geq_MinLatLB)

Fault Explanation

The latitude from a UAS's flight plan is not physically possible.

Additional Notes

Latitude can only ever by between -90 and 90 degrees. Anything outside these bounds is nonsensical and indicates a fault within the system.

Figures

Figure 1: All of the flight plan's latitude (fpLat) waypoints from each GCS the UTM reads from the waypoint flight plan datatable.
Figure 2: The output of R2U2's monitoring of specification SB_UTM_5, confirming that no latitude waypoint from a UAS's flight plan exceeds its sensor bounds.
Figure 3: Since Fig. 1 had no fpLat inputs that exceeded MaxLatUB or MinLatLB, we manually injected a fault into a single flight plan's waypoint (purple).
Figure 4: The output of R2U2's monitoring of specification SB_UTM_5, showing that R2U2 catches when the injected fault occurs.