Over time, users may encounter pre-arm errors that will prevent takeoff. Usually the user will take note of pre-arm errors in the bottom center of the screen, displayed with a yellow dialog box. The user can also view a log of errors via the megaphone icon on the icon bar at the top of the screen. The icon has two states: no alerts and unread alerts. If there are no alerts it will be displayed as a megaphone icon, and unread alerts will display as a triangular warning icon.
Below, a list of pre-arm errors that the user may encounter during general operations has been compiled, along with actions the user can take to resolve them.
No GPS Lock - Check the number of satellites you’re receiving, which can be done by viewing the number next to the satellite icon on the icon bar at the top of WISPR Ground Control. If there are less than 13, reboot the drone. If that doesn’t clear the error, try moving the drone to a different location- ideally wherever offers the maximum clearance between the GPS and the sky. Obstructions can have a significant impact on satellite detection. You will know you have achieved GPS lock when the LED lights on the sides of the GPS are blinking green and continue to do so.
GPS High HDOP - This triggers based off of a function that measures position accuracy, and can appear in flight modes where GPS is necessary. Allow a small amount of time to elapse in order for the GPS to settle, as sometimes this error can clear itself without need for action. If the error persists, try either rebooting the drone, or moving the drone to different location especially away from metal objects. Even rebar directly underneath concrete the drone is resting on could potentially trigger this.
GPS Glitch - This occurs when the GPS is not reading the correct coordinates for more than 5 seconds. This usually will resolve itself by waiting for the number of satellites to increase. If it doesn’t clear on its own, move the drone to a different location, paying heed to metal nearby. A reboot can potentially solve this as well if you seem to be unable to find ideal positioning. If the error persists, the GPS needs to be inspected- and likely recalibrated.
Need 3D Fix - This error occurs when the drone is in a mode where it requires a GPS signal to take off, but the GPS signal isn’t strong enough. It is handled in much the same way as the GPS Glitch and High HDOP errors, as they are all GPS centric. This can almost always be solved by moving the drone a few feet over from its current position. A common cause of this is the presence of metal in the ground beneath where the drone rests. If that does not fix it, a simple reboot should fix it. If neither of these work, it may be time to look at the GPS for hardware issues.
Battery Below Arming Voltage - You will receive this error if the drone detects the voltage output of the currently equipped battery is too low. This occurs to prevent beginning a flight with a battery that may deplete too quickly and result in a crash. Charge the battery completely before flying, or swap to a fresh battery.
For a guide with information relevant to this error, check out this link:
Downloading Maps While Offline and Setting Terrain Follow
Pre-Arm: Check Proximity Sensor - There may be an object too close to the sensor, or the sensor may be malfunctioning. Generally the best practice is moving the drone to a spot where it is less likely to pick up anything that will cause the pre-arm, but sometimes this issue won’t resolve itself until a reboot occurs. Occasionally, allowing some time to elapse will let the sensor recognize a falsely detected obstruction, and it will clear the error. Try these approaches multiple times. If the sensor continues displaying the error, the option to disable it exists in the general tab of the WISPR Ground Control settings. You can find this by tapping the WISPR logo in the top left corner of WISPR Ground Control.
If you opt to do this, please exercise extreme caution when flying. With this setting disabled, the drone has no collision avoidance active and nothing will prevent the drone from flying directly into an obstacle or bystander.
Compasses Inconsistent - This is caused from reading the Internal and External compasses as pointing in different directions. Reboot the drone. If the same pre-arm error continually appears, a compass calibration should fix this.
Pre-Arm: ESC Temp Over Threshold. False Reading Detected - This error occurs when temperatures are very cold. The values for the ESC temps range from 0-255 degrees Celsius. When the value is read as below 0 from the cold, it will cause a false reading that registers the ESC temps as maximum. This error appearing just confirms the drone has detected the false reading. Do not be alarmed by this error, as it will not alter the drone’s behavior and should have no impact on pending operations. If you see this, you may safely close the message box and continue.
Low Battery Failsafe RTL - This means the drones has calculated how far it is from home and how much battery it will take to get back to home safely. This sequence should never be cancelled unless in an emergency, in which case the drone should be landed immediately.
Gyros Not Healthy - Limited information regarding this error is present. Rebooting the drone should clear this error.
OpenDroneID: Arm Status Not Available (Lost Transmitter) - Occasionally you may encounter this on if the transmitter is not found quickly enough during boot. It may appear with several other temporary pre-arms or messages that often are present during the boot period while the drone initializes and acquires GPS lock. Lost transmitter will only be displayed once, and if the transmitter is found a message will appear in the alerts window (megaphone icon). “OpenDroneID: Arm Status Not Available” will be appearing every so often.
This happens as a result of a de-sync between the Remote ID transmitter and the controller, with the transmitter being the component which WISPRGroundControl cannot establish a connection with.
Presently the only known solution to this is to reboot the drone. While this almost never occurs in sequence, if you should find this happening consecutively, leave the drone unplugged for 3-5 minutes before rebooting. If you’re unable to get past this issue after 10+ reboots (should be rare) with time between attempts, there may be a problem with the transmitter.
OpenDroneID: Operator Location Must Be Set (Lost Operator Location) - This issue is twin to the “Lost Transmitter” error. This happens when the controller becomes desynced rather than the Remote ID transmitter. You will see this when you’re in a location that blocks GPS signal thoroughly enough that the controller’s location cannot be established.
This can usually be resolved by taking the controller outside if indoors (most applicable if inside a metal building). If that doesn’t solve your problem or you are already outside and encountering this, reboot WISPRGroundControl. Usually there should be no need to reboot the drone, but if the error persists after a few reboots of WISPRGroundControl, reboot the drone.
If the problem still persists, you may change your location from “High Accuracy” to “Device Only” by dragging the top of the screen downwards to expand the ribbon. Press and hold the location “pin” icon, and change the selection to device only. You will need to exit WISPRGroundControl and reboot the drone for this to take effect.
OpenDroneID: System Not Available
This message seems to sometimes occur when the controller location is not found during initialization, but then found afterward, or if the drone was connected to Mission Planner while WISPRGroundControl was booted. 95% of the time this can be solved by rebooting WISPRGroundControl and waiting for parameters to finish. The message should clear after a 5-10 seconds if not sooner. Alternatively, sometimes this message will clear on its own if left booted for a few minutes. If this persists, a reboot is necessary.
How should I proceed if the Error “PreArm: OpenDroneID: System not available" or “Controller Location Lost” persists and cannot be cleared on my Herelink Controller?
Open the WisprGroundControl application and allow parameters to load. If the error “PreArm: OpenDroneID is shown and persist, follow the steps below if the error perssists, ou will see tyhe PreArm error "System not available."
Swipe down from the top of the Herelink screen to see the drop-down menu.
Ensure your location Icon is lit up on the drop-down menu (meaning your location is turned on on the RC). If the icon is not lit up bright: quick press the icon to turn your location on.
Once you ensure the location is on, press and hold the location icon.
Select Mode. A screen with 3 options will show. Select Device only (Use GPS to determine location).
Press the back arrow once beside Location mode.
Select the Hamburger button (the triple bar ≡) next to location.
Scroll down to Date & Time under system and select it.
Ensure Automatic date & time is toggled on and select “Select time zone”
Scroll through the time zone options and choose the time zone corresponding to your flight location.
Press the square icon on the left side of the screen to close out and either swipe the app to the right to close the app or press close all above all apps.
Reboot your Herelink controller by holding the power button to power down and preessing power off.
Turn the controller back on by holding the power button down unitl you see the Herelink Icon appear and then the home screen.Open up WisprGroundControl. The error should now be resolved.
PreArm Remote ID : waiting on initialization - The PreArm error occurs when the RemoteID module does not transmit a signal promptly. This issue may occasionally arise but is not cause for concern. To resolve it, please close WISPR Ground Control, reboot the drone, and then reopen WISPR Ground Control. The PreArm error should no longer be present.
You are using MAV_FRAME_GLOBAL_TERRAIN_ALT in a mission. WisprGroundControl does not support terrain tiles to vehicle - To eliminate this error you will Remove the mission from the UAS, Remove the mission from WISPR Ground Control, Select “No Payload” under the Payloads tab. Reboot your WISPR UAS and WISPR Ground Control and select “Bathemetry Payload” under payloads. Reboot the UAS once more and re-plan your mission. The error should be cleared and you are now ready to plan and run a bathmetery mission.