In Situ Testing Suggestions

You must do the final testing at sea. This is an uncontrolled environment for testing, however, there is a useful total system test of the velocity correction. Fixed ground targets should have 0 corrected velocity as observed from the moving platform. Do not use buoys with radar reflectors. They are excellent targets, but they are generally not stationary.

Cruising offshore at ~10 km (6.2 mi) and observe fixed ground targets while collecting IRIS data. You may want to use a sector scan for this at low elevation. Verify the following:

• The real time color display should show ground targets at zero velocity.
• The Rays utility should show targets at zero velocity.
• PPI velocity products with a fine resolution velocity scale can be constructed to verify the velocity correction.

If the corrected velocity of ground targets is not 0, you must isolate the problem. If the antenna is properly stabilized, it is likely that both the INU (or Gyro system) and the antenna controller are functioning properly. Therefore, the error is most likely due to alignment:

• The INU or Gyro system vertical and the antenna vertical must be co-aligned.
• The INU or Gyro system azimuths must be co-aligned.
• The moment arms must be properly measured.

The INU or Gyro/Antenna alignment can be checked with the sun tracking feature of the Antenna utility. The moment arm measurement can be checked dynamically.