1 Introduction
1.1 Related Work
2 Setup
2.1 Mission
2.2 Non-Intrusive Instrumentation
2.3 StreamLAB
2.4 FPGA as Monitoring Platform
2.5 RTLola Specifications
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Sensor Validation. Sensors can produce incorrect values, e.g. when too few GPS satellites are in range for an accurate trilateration or if the aircraft flies above the range of a radio altimeter. A simple exemplary validation is to check whether the measured altitude is non-negative. If such a check fails, the values are meaningless, so the system should not take them into account in its computations.
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Geo-Fence. During the mission, the aircraft has permission to fly inside a zone delimited by a polygon, called a geo-fence. The specification checks whether a face of the fence has been crossed, in which case the aircraft needs to ensure that it does not stray further from the permitted zone.
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Sensor Cross-Validation. Sensor redundancy allows for validating a sensor reading by comparing it against readings of other sensors. An agreement between the values raises the confidence in their correctness. An example is the cross-validation of the GPS module against the accelerometer. Integrating the readings of the latter twice yields an absolute position which can be compared against the GPS position.
2.6 VHDL Synthesis
Spec | FF | FF[\(\%\)] | LUT | LUT[\(\%\)] | MUX | Idle [mW] | Peak [W] |
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Geo-fence | 2,853 | 3 | 26,181 | 71 | 4 | 149 | 1.871 |
Validation | 4,792 | 5 | 34,630 | 67 | 104 | 156 | 2.085 |
Cross | 3,441 | 4 | 23,261 | 46 | 99 | 150 | 1.911 |