Transcript Piccolo Log on Flightgear - Illinois Space Grant Consortium

Running Piccolo Log on
Flightgear
Young Mo Kang
ECE @ UIUC
Piccolo?
• A family of autopilot systems from
Cloud Cap Technology
• Loaded on UAVs (Unmanned Aerial
Vehicles)
http://www.cloudcaptech.com/piccolo.htm
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
http://www.flightgear.org
How?
• It has to read in data via
1. File
2. Socket (TCP or
3. Namedpipe
4. Serial
UDP)
Setup
• A server broadcasting data
• A client running Flightgear
server
Network connection
client
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
client
server
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