Dan Bobyn
Engineering Ltd.












Recent Projects




L1/L2/L5 GPS Signal Generator RF Subsystems

This project involved designing a dual channel L1/L5 SBAS signal generator and a L2/L5 variant.  The project team included specialists in GPS signal design, FPGA design and firmware design in addition to the RF contractor. 

The resulting hardware chassis included a clock reference board, baseband signal/microcontroller boards, RF signal generator boards and power supply.  One version of the Signal Generator was sent to Europe for GPS SBAS testing after obtaining CE EMC and Safety approval.  Another version of this chassis underwent commercialization and is being used in the L5 WAAS upgrade program and other SBAS programs around the world.

     L1/L5 SigGen Chassis - Cover Off

The RF circuits include clock reference board and the L1, L2 and L5 RF boards. 

The clock reference board generates 10, 75 and 300 MHz synchronous clocks from an internal OCXO or external 10 MHz reference signal. 

The L1, L2 and L5 RF boards contain:

  • DDS based Code Clock Generator
  • DDS based Carrier generator to a resolution of about 1 micro-Hz 
  • I/Q Signal Modulator
  • Programmable level 70 MHz IF output (for the Satellite uplink)
  • Switchable IF Bandwidth settings 
  • L Band output connection (for local feedback and testing)
  • A/D Sampled code clock feedback circuitry

              RF Board (L2 version - shields removed)

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2018 Dan Bobyn Engineering Ltd.