High Speed and Dynamic Switching Type Signal Generation on FPGA for Emulating the Test Signals for Navigation Receivers

Abstract

In present aviation, navigation is a significant technology.  So  far,  equipped  in  almost  all  the  civil and military  airports,  radio  navigation  system  is  most  widely employed  navigation  devices  in  aviation.  At  present,  radio navigation  still  has  priority  in  short-range  navigation  of civilian and military  aviation  in our country. Also, because of the imperfect landing system device in existing aircraft, radio navigation system is of imperative importance in ensuring safety in the Plane’s homing and approaching.
 
In  the  real  navigation  test,  to  create  the  RF signal  of  combined  antenna  in  radio  navigation,  numerous  signal generators  are  often  designed  to  satisfy  performance  of  navigation  system  and  meet  technological  requirements. Meanwhile,  the  signal  generator  should  adjust  signal  types, parameters  and  work  modes  timely  according  to  the navigation  system  requirements.  Thus,  signal generator should  have  the  function that  signal  can  be  generated flexibly,  parameters  alter  quickly,  signal  spectrum  stay stabilized,  and  the  system  is  reliable,  and so forth. 

The proposed system  adopts Micro Blaze  soft  processor  as  the  control  core  of  generator to  communicating  command  with  the PC.  which  can  satisfy  each  requirement  in real  application of  testing  and debugging on  the navigation.

The significant  role  in  navigation  test,  radio navigation  generator  is  widely  employed  in  the  people/military plane.  But traditional equipment composed of analog circuit Presents low correctness and poor reliability.  A new type of digital navigation signal generator is designed.  It gets data and commands from PC by the Micro Blaze embedded soft processor of Xilinx Company and demodulates information to control FPGA load dissimilar software’s to generate numerous navigation signals, which fully meets general radio navigation system test technical requirements by giving full play  to  the  system  hardware  and  software  advantages  and fulfilling  design  targets  such  as  the  accurateness,  flexibility  and expansibility. Thus, offers a new idea for radio navigation system.  this  generator  can  be widely applied  to  debugging  use  on  people/military  plane  radio navigation.

Using FPGA instead of an ASIC gives also flexibility for reconfiguration, which is a need for the Software Defined Radio (SDR) concept.  Modelsim Xilinx edition will be used for simulation. The Xilinx ISE will be used for synthesis; place & route and bit file generation. Xilinx Spartan 3E family FPGA board will be used testing the logic.

Implementation of the project:

In this project we are implementing the analog and digital modulation techniques.

Analog: AM, FM
Digital:  Bpsk, Qpsk

The parameters that are need for the modulation like carrier angle, frequency, and kind of mode cane be differed by using the soft core processor called Micro blaze. And the message frequency can be varied by using function generator.