Testing Relative Bearing Measurements

You can test if the relative bearing measurements are correctly calculated by the door sensors.

Testing Bearing at the Office

You can do a basic installation at the office to test the bearing measurements received from the door sensors.

Before you begin

For this task you need:
  • An operational system
  • Two large-band active or passive hydrophones
  • One door sensor (master or slave) with positioning option

Procedure

  1. Open the system web page and click Hydrophones.
  2. Add the two hydrophones:
    1. Select the location of each hydrophones.
    2. Set Rx/Tx to Receive.
  3. Click Positioning.
  4. Set the positioning settings:
    1. Enter a baseline of 1 meter and leave the other settings to 0.
    2. In Inputs, enter the port and starboard hydrophones.
  5. Place the two hydrophones side by side and a few meters in front of a door sensor. The sensor must be aligned with the hydrophones.
  6. From Scala2, check that the bearing measurements are +/- 1°.
  7. Move back the starboard hydrophone of approximately 5 cm.
    The bearing should be between -10° and - 15°.
  8. Move back the port hydrophone of approximately 5 cm.
    The bearing should be between + 10° and + 15°.
    Trouble: If the data is outside the recommended values, check the following points:
    • The baseline must be set to 1 meter.
    • The sensor must be aligned with the hydrophones.
    • The positioning settings in the receiver must be the same as the sensor's settings set in Mosa2.

Testing Bearing at the Harbor

You can test the bearing measurements at the harbor to make sure the system is coherent, from the hydrophone connection to the hydrophone settings in Scala2.

Before you begin

The positioning system has been configured.

Procedure

  1. For each door sensor, tie a line to the front and a line to the back so that you can point them.
  2. Secure the lines to the stern with the Master sensor on port side and the Starboard sensor on starboard side.
  3. Place the sensors deeper than the vessel keel. The sides of the sensors with a circle/A must point toward each other and the uplink signal must point toward the hydrophones.
  4. On Scala2 bearing angles should be negative for the port sensor and positive for the starboard sensor.
  5. On Scala2 bearing angles should be above 180° for the port sensor and below 180° for the starboard sensor.

What to do next

Note: You can also test the bearing measurements while at sea: if the sensor in water is correctly aligned with the hydrophones, the bearing should be +/- 2°.