Running Piccolo Log on Flightgear Young Mo Kang UIUC

Piccolo? A family of autopilot systems from Cloud Cap Technology Loaded on UAVs (Unmanned Aerial Vehicles)

What? Sensors (accelerometer, gyroscope, …) GPS Communications link for data transfer UAV Ground station

And… Piccolo sends real-time telemetry data to the ground station computer The ground station computer logs the data on a text file Sample log file

What about Flightgear? An open source flight simulations program Simulates a flight

How? It has to read in data via 1.File 2.Socket (TCP or UDP ) 3.Namedpipe 4.Serial

Setup A server broadcasting data A client running Flightgear serverclientNetwork connection

Tasks Convert the Piccolo log file into a replay file Broadcast the replay file to client

Conversion From Piccolo log file To FGNetFDM data structure defined in net_fdm.hxx of Flightgear source file Simple task if all correlations between Piccolo log file and FGNetFDM data structure are figured out

Correlations Many can be directly retrieved from the log Some need to be calculated from other values And others to be figured out

Once figured out Data values are assembled into the structure Little endian to Big endian byte-order swapping Saved as a replay file

Broadcast Reads in the replay file just created Whenever Flightgear receives the packet, it will display on the screen immediately Data need to be transmitted at the same rate as they were logged Decide whether to broadcast a packet of data or wait

Time stamps cur_time stores the UNIX time value Broadcasting program needs to refer to the value for each time frame data However, UNIX time is accurate up to 1 sec MAX 1 frame per sec Causes abrupt changes in scenery on Flightgear

Solution Instead of UNIX time, Piccolo’s system clock time is stored in cur_time during conversion process clock time is accurate up to 1 ms x1000 more frames per sec possible Smooth scenery transition (of course, only if data were logged at high enough frequency)

Testing server client

Thoughts Can replay test flights with/without manipulations of the log file Can be implemented to any type of log formats NOT RESTRICTED TO Piccolo with slight modifications Can be used to test and simulate optic flow algorithms by changing to cockpit’s view