2. Grasshopper Mode#

2.1. Route requirements#

Grasshopper action is executed on waypoints with Wait action assigned. Route may consist of mixed type of waypoints (Adaptive bank turn and Stop & turn), to navigate drone to survey area, and for survey have waypoints with Wait action. In the Grasshopper mode all waypoint turns will be executed as Stop & turn.

2.2. Flight#

  1. Start the PC and connect it to the Wi-Fi network. Start the UgCS and plan a mission for the drone. The descent points must be set as wait action, the wait duration defines waiting time in the descent point.

  2. Turn on the drone, the payload, and SkyHub device.

  3. Turn on the DJI Remote Controller and connect to the same Wi-Fi network as the PC. Be sure that the flight mode switch on the DJI Remote Controller is in N-mode. Run the UgCS Companion mobile application. Wait for the application to show the main window and connect to UgCS. The UgCS connection indicator in UgCS Companion should become green.

  4. Ensure that the drone with a correct profile appears in the UgCS on the PC and all drone indicators (battery, uplink, downlink, satellites) are green. Select the drone and the mission.

  5. Ensure that only the used payloads are enabled in the UgCS-CPM Payloads section. Each payload should be properly configured (see Sensors and Payloads part of the documentation).

  6. Erase old log files if they are no longer needed (see Log Files Management for details).

  7. Start the UgCS-CPM application and connect to UgCS with default credentials. Check the UgCS, Drone, and SkyHub indicators are green. Add the Terrain Following widget and other widgets related to connected payloads by clicking the plus button.

../../../_images/screen_grashopper.png

UgCS and UgCS-CPM application open side-by-side#

  1. Check the Altimeter widget for it displays the altimeter data. Check the altitude Min/Max limits in altimeter widget settings. Note that there is no data from the radar altimeter until the drone is moving. Gently shake the drone by hand until the altitude starts to change.

../../../_images/GHP_min_max.png

Altimeter Min/Max value configuration#

  1. Check the Altimeter widget for it displays the altimeter data. Note that there is no data from the radar altimeter until the drone is moving. Gently shake the drone by hand until the altitude starts to change.

  2. Upload the route to the drone using UgCS. Once the route is uploaded to the SkyHub, Grasshopper parameter can be configured.

  3. Go to the Grasshopper widget, press Refresh to read current GH settings.

../../../_images/GHP_widget.png

Grasshopper widget#

12. Set Target Altitude for flight between measuring points in True Terrain Following mode. Set Descent altitude - altitude to which the drone will descend during Grasshopper action. Set Safe altitude - altitude to which the drone will ascend if the altimeter reading goes out of range and when the Grasshopper route is finished. Press Apply to save values.

Warning

Attention: It is strongly recommended not to set Target Altitude more than 10 meters for the laser altimeter above water

  1. Press the Configure button. Wait for the Grasshopper ENABLED message.

  2. If there is no message mentioned above, change the flight mode switch to F-mode and back it to N-Mode, then try again to press the Configure button.

  3. Take off using the DJI Remote Controller or from the UgCS and rise up to the appropriate altitude (see limits from step 8).

  4. Press the Activate button in the Grasshopper widget to start the flight in grasshopper mode. The alternative way to activate it is to move the flight mode switch to F-mode or press Start in UgCS Companion application.

  5. You may interrupt the flight by moving the flight mode switch to N-mode or by pressing the Pause button in the Grasshopper widget (UgCS-CPM), or Pause button in UgCS Companion application.

The flight can be resumed by moving the flight mode switch to F-mode, or by pressing the Resume button in the Grasshopper widget (UgCS-CPM), or Resume button in UgCS Companion application.

During pause you may manually control the drone, for example fly around an obstacle. In this case the drone returns to the nearest point on the route by the shortest way after resuming.

Warning

Attention: the flight mode on the DJI Remote Controller must be obligatory switched back to N-mode before manually control. Otherwise, the drone returns to an unexpected resuming point.

  1. If the drone descends below the minimum allowed altitude or ascends above the maximum allowed altitude (see step 8), it stops, then climbs to increase its altitude to the value defined by the Safe altitude parameter in the Grasshopper widget, and then the route pauses.

../../../_images/GHP_widget.png

Grasshopper widget#

You may manually correct drone position and resume the flight according to recommendations in the step 17.

  1. After the mission has been completed, the drone stops at the last waypoint, then climbs to increase its altitude to the value defined by the Safe altitude parameter in the Grasshopper widget.

  2. Return the drone to the desired landing position, and land. If the flight has been ended over the desired landing point, press the Land button in UgCS.

  3. Download log files (see Log Files Management).

2.3. Configuration Parameters Summary#

Parameter

Default

Min

Max

Precision

Unit

Description

Safe altitude

5

0.1

50

0.1

m

Safe altitude drone will take in case of failsafe or at the end of the route

Descendant altitude

3.0

0.0

1000.0

0.01

m

Grasshopper descent altitude

Target altitude

5.0

0.0

1000.0

0.01

m

Grasshopper flight target altitude

Descent speed

1.0

0.0

1000.0

0.01

m

Descent speed at grasshopper action points