Proc. SPIE. 8045, Unmanned Systems Technology XIII
KEYWORDS: Defense and security, Safety, Detection and tracking algorithms, Receivers, Geographic information systems, Signal processing, Sensing systems, Algorithm development, Collision avoidance, Global Positioning System
Military and other national security agencies have been denied unfettered access to the National Air Space (NAS)
because their unmanned aircraft lack a reliable and effective collision avoidance capability. To overcome the constraints
imposed on UASs use of the NAS, a new, conformable collision avoidance system has been developed - one that will be
effective in all flyable weather conditions, overcoming the shortfalls of other sensing systems. Upon implementation this
system will achieve collision avoidance capability for UASs deployed for national security purposes and will allow
expansion of UAS usage for commercial or other civil purposes.
Typical airborne Light Detection and Ranging (LIDAR) used for oceanographic
measurements collect data at rates in the range of 1 Megabyte per second. This paper presents
a method for organizing and displaying this great bulk of data to allow screening for areas of
interest. In addition, this method can be transferred to dedicated hardware, to provide a 100%
real time data display system at a reasonable cost.
A typical airborne LIDAR system contains a scanning transceiver, and digitizes returned
waveforms as the aircraft ffies some search pattern. Thus the data is inherently four
dimensional (intensity and three spatial dimensions). This method reliesupon collapsing the
four dimensional data into three dimensions; color and X,Y screen coordinates. This is doneby
translating depth into an RGB color mix, and return intensity into RGB intensity. Thus color
represents depth, and brightness represents signal strength. This data is then displayed on a
high resolution color display.
In order for this to be successful, some preprocessing is necessary to normalize the
waveforms, so that changes in the displayreflect changes in the water column. In addition, some
digital filtering is beneficial to increase the signal to noise ratio.
This system is currentlyimplemented in Greenhills 'C' under CLIX (UnixVport toClipper)
running on a Zaiaz 933 compute engine, with RASIL graphics software package on a Zaiaz FB
640 Graphics frame buffer. This hardware provides 5 MIPS average execution rate and 16.7
million colors on a 768 x 576 pixel display.