1. Summer Tasks on UAV Radar
Goddard Space Flight Center
Summer Tasks on UAV Radar
Manuel A. Vega-Cartagena
UPRM Graduate Student
Under supervision of:
Shannon Rodríguez
Lihua Li
Gerry Heymsfield

2. Manuel A. Vega-Cartagena
Objective
NASA IDEAS-ER grant received.
Develop a background on radar design while contributing to the UAV project.
Manuel A. Vega-Cartagena

3. Manuel A. Vega-Cartagena
UAV Radar Project
The planned radar will have capabilities of ER-2 Doppler Radar (EDOP).
Nadir beam for vertical winds and precipitation structure.
Conical beam for ocean surface winds and surveillance of the precipitation regions of the storm.
Manuel A. Vega-Cartagena

4. Manuel A. Vega-Cartagena
Tasks
Study radar literature.
Redesign UAV’s nadir sub-system RF front end block diagram.
Help bench test UAV’s conical sub-system Tx and Rx paths.
Design 80MHz/5MHz clock PCB.
Design a PCB for UAV’s Vicor power modules.
Manuel A. Vega-Cartagena

5. UAV’s RF Front End Block Diagram
Requirements
Magnetron frequency = GHz
Intermediate frequency = 60 MHz
Calibration noise injection loop
Receiver noise figure calculations
Manuel A. Vega-Cartagena

6. UAV’s RF Front End Block Diagram
Manuel A. Vega-Cartagena

7. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
Requirements
Single 10MHz sine wave input.
80MHz and 5MHz TTL clock outputs for DAQ card.
Four amplified analog sensing lines.
Low profile components.
PMC daughter card format.
Original circuit design done by Shannon Rodríguez.
Manuel A. Vega-Cartagena

8. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
Clock Block Diagram:
Manuel A. Vega-Cartagena

9. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
PCB Construction
Board schematic and layout done with Orcad software.
Built using router in building 22.
D-Sub 15
Sense Lines
SOIC
Components
Mezzanine
Connectors
Manuel A. Vega-Cartagena

10. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
Board Testing
CPCISYS carrier board with daughter card.
Only DC Power from carrier board used.
Still undergoing debugging process.
Manuel A. Vega-Cartagena

11. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
Test Results
80MHz Clock Signal
~1.3V
~0.4V
Manuel A. Vega-Cartagena

12. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
5MHZ Clock Signal SMA
~1.6V
~0.1V
Manuel A. Vega-Cartagena

13. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
Sensing Lines
Two additional lines were added.
Two inverting amplifier stages.
Gain values were changed.
Manuel A. Vega-Cartagena

14. Manuel A. Vega-Cartagena
80MHz / 5MHz PCB
Sense Lines
Tested using 10Vpp 1kHz sine wave.
Theoretical voltage gain value = 2.25.
Gain variations may be caused by tolerance in resistances.
Sense Line
Output Voltage (Vpp)
Voltage Gain 1
19.53
1.953 2
20.31
2.031 3 4
Manuel A. Vega-Cartagena

15. Vicor Power Modules PCB
Requirements
Eliminate wire connections between modules.
Reduce mounting time.
Only one board for both +/- voltage configurations.
Output voltages should be accessible and easy to change(+/- 5V, +/-12V, +/-15V).
Manuel A. Vega-Cartagena

16. Vicor Power Modules PCB
Design Schematic
Power modules PCB.
Voltage selection jumper and output.
Wire connections elimination.
Bypass capacitors.
Chassis ground connection.
Manuel A. Vega-Cartagena

17. Vicor Power Modules PCB
PCB Construction
Maximum load currents calculation.
Imax = 5 for 5V module.
12V and 15V modules have lower output currents.
Track widths for 10°C temperature increase = 110 mils.
Track clearances for +28V = 29 mils.
Entire design done using standard low-cost 1oz. Cu thickness board.
Components selection.
Connectors with unexposed contacts.
Manuel A. Vega-Cartagena

18. Vicor Power Modules PCB
Finished Board
+28V Input
Output and Voltage
Selection Jumper
Chassis Ground
Manuel A. Vega-Cartagena

19. Vicor Power Modules PCB
Power Distribution Matrix
Used to eliminate barrier block.
Makes output voltages more accessible and easy to change.
From Aircraft
To Components
To Power Modules
From Power Modules
Manuel A. Vega-Cartagena

20. Vicor Power Modules PCB
Finished Board
From Aircraft
From Power
Modules
To Power Modules
To Components
Manuel A. Vega-Cartagena

21. Vicor Power Modules PCB
Final Configuration
Manuel A. Vega-Cartagena

22. UAV’s Conical Sub-System Tx and Rx Paths Testing
Task performed to gain hands-on experience.
Manuel A. Vega-Cartagena

23. Manuel A. Vega-Cartagena
Learning Experience
Radar Theory Background
RF Front End Design
Power Requirements
PCB Design
ORCAD
Routing machine
Design Implementation
Manuel A. Vega-Cartagena

24. Manuel A. Vega-Cartagena
Conclusions
Goals achieved!
80MHz/5MHz daughter card PCB developed
Power Modules PCB design developed
Gained valuable hands-on experience.
Manuel A. Vega-Cartagena

25. Manuel A. Vega-Cartagena
Questions
Manuel A. Vega-Cartagena

26. Manuel A. Vega-Cartagena
List of Acronyms
UAV – Unmanned Air Vehicle
IDEAS – Initiative to Develop Education through Astronomy and Space Science
DCAS – Distributed Collaborative Adaptive Sensing
PCB – Printed Circuit Board
TTL – Transistor-Transistor Logic
Manuel A. Vega-Cartagena

27. Manuel A. Vega-Cartagena
Acknowledgements
Shannon Rodríguez / 555
Lihua Li / 912
Gerry Heymsfield / 613
Wai Fong / 567
Gerry McIntire / 613
Manuel A. Vega-Cartagena