senior projects laboratory ece 4773
Post on 03-Jan-2016
36 Views
Preview:
DESCRIPTION
TRANSCRIPT
SENIOR PROJECTS LABORATORY
ECE 4773
Team 5B: Side Lobe Canceller
Micah Nelson Rafael Mendoza Kari Gammons
Michael Lee
• PROJECT• Sidelobe Canceller for a 915 MHz Atmospheric
Radar
• MENTOR(S)• Dr. Bob Palmer• Dr. Tian Yu• Chad Kidder
• OBJECTIVE• Research, design, and build a sidelobe canceller,
SLC, which will receive interference, known as clutter, caused by sidelobes from the LAP-3000 RADAR system
Design Approach
• Design was developed to be compatible with the LAP-3000 radar
• Design of receiver based on the LAP-3000 receiver design
Vaisala LAP-3000 RADAR
• Lower Atmosphere Doppler Wind Profiler
• Used for weather applications
Clutter Screen is Absent
Specs
• Measurement height– Min = 100 m for wind– Min = 100 m for temp– Max = 2 to 5 km for winds– Max = 1 to 2 km for Temp
• Min Vertical Resolution– 60 m for wind– 60 m for temp
• Radar Frequency– 915 MHz
Sidelobes
• Side lobes are part of the radiation pattern from the radar that are not the main beam. The power of the side lobes is normally much less than the power of the main beam of the radar.
http://en.wikipedia.org
Configuration
LAP3000RADAR
RECEIVER
RECEIVERRECEIVER
RECEIVER
ReceiverBox
IndoorBox
DCAC
ANTENNA
60 MHz
855 MHz
60 MHz
855 MHz
I Q I Q
Inside Structure
915 MHz
+ +_ _
100’
15’
IF 60 MHz
System Block Diagram
10 dBm
36 V DC 2 A
Baseband
Receiver Block Diagram
915 MHz
PREAMPLIMITER BANDPASSFILTER
MIXER
AMP
LOCALOSCILLATOR
AMP
BANDPASSFILTER
QUADRATUREDETECTOR
IF/Detector
LOWPASSFILTER
I Q
855 MHz
60 MHz
Baseband
Dual Matched Bessel Filters
60 MHz
LOWPASSFILTER
Recommended
Schedule
Action Items
ACTION WHO DUE DONE
Pick Parts and Specifications Michael/Rafael/Micah 1-Mar X
Purchase Micah/Michael/Rafael 2-Mar X
Measure Backscatter Kari/Micah/Michael/Rafael 4-Mar X
Measure Signal Strength Kari/Micah/Michael/Rafael 4-Mar X
Measure Power loss in 100 ft. SMA Rafael/Micah/Michael/Kari 10-Mar X
Prepare Materials Kari 10-Mar X
Organize Schedule Micah/Kari 10-Mar X
Construct Circuit Rafael 14-Apr X
Cost Comparison Analysis
Cost Allowance $3000.00
Initial Target $2500.00
Initial Cost Estimate $2200.00
Final Cost $2239.65
Schedule Comparison Analysis
Estimated Work Hours
Actual Work Hours
Difference %Expended
Kari 186 173 -13 93%
Rafael 243 234 -9 96%
Micah 216 168 -48 78%
Michael 225 246 21 109%
Total Hours 870 821 -49 94%
Recommendations
• Baseband may be amplified as needed• Digital accounting for difference in magnitude of
I and Q output signals may be done• A limiter may need to be added to the design
immediately after the antenna for added protection
• System gain can be reduced to remedy Intermodulation that may occur at higher dBm ranges such as signals greater than -40 dBm
• Variable attenuators may have better results for future use as a replacement for fixed attenuators
top related