1 Diploma/Master's Thesis in Computer Science
3 Supervisor: Dr. Stephan Schulz, stephan.schulz@comsoft.de
4 Dr. Marina Müller, marina.mueller@comsoft.de
6 "An Explicit Rule Language to Express Safety Constraints for
7 Minimum Safe Altitude and Area Proximity Warnings"
9 Safety Net applications are computer programs that monitor the air
10 situation based on data from sensors (radars, multilateration, ADS-B)
11 or, more often, tracker systems that integrate data from sensors over
12 time. These programs try to predict critical situations and alarm ATC
13 controllers ahead of time. Examples include Short Term Conflict Alert
14 (STCA) systems, Minimum Safe Altitude Warning (MSAW) systems, and Area
15 Proximity Warning (APW) systems. STCA systems predict the flight paths
16 of different aircraft and issue a warning up to two minutes ahead of a
17 potential separation violation. MSAW and APW systems predict single
18 aircraft trajectories and issue a warning if there is a significant
19 risk that the aircraft comes too close to a terrain feature,
20 obstacle, or prohibited region.
22 While the basic trajectory prediction is always based on the same
23 principles, the generation of warning messages is highly dependent on
24 local conditions. The quality of the sensor coverage dictates aircraft
25 separation rules. Local geography may require trajectories that would
26 normally be avoided. Availability of flight plan information can help
27 to recognize potentially dangerous situations as already anticipated
28 and under control. As an example, if a flight plan contains a cleared
29 altitude of 300 flight levels, the aircraft is expected to level off
30 its ascent there, and hence will not conflict with an aircraft at an
31 altitude of 320 flight levels, even if a naive projection based on the
32 current rate of ascent does indicate a potential conflict.
34 Currently, Safety Net systems use standard requirement engineering to
35 identify the necessary conditions for each particular
36 deployment. These requirements are then translated manually into
37 program code. However, this process is tedious and error-prone, and
38 the resulting code can be rather complex and hard to maintain. Each
39 modification requires extensive re-validation of the software.
41 The aim of this thesis is the development and implementation of a
42 language that can express the necessary conflict for an ATC Safety Net
43 in symbolic, human-readable form. Depending on the outcome of an
44 initial feasibility study, the language should be either interpreted
45 by the Safety Net System, or automatically compiled into C++ code.
47 For this purpose, first the necessary attributes and relations have to
48 to be identified. Then a proper rule semantics (prioritised, weighted,
49 non-monotonic/exception-based...) has to be determined, and finally an
50 initial prototype language needs to be designed and implemented.
53 Comsoft is a medium-sized, privately owned company located in
54 Karlsruhe/Durlach. We continually offer interesting diploma topics,
55 practicals, and internships in computer science, signal processing,
56 electrical engineering, and related topics. For generic enquiries
57 please contact human resources at waltraud.schweitzer@comsoft.de.