Last Updated on February 14, 2021 by Markeyus Franks
When the weather is beautiful, flying a drone over water is the perfect chance to get that picture video shot. But some easy pro tips keep your drone safe if you’re flying it within water-based locations. Here are 6
great tips that every drone enthusiast should follow.
Vision Position Sensors (VPS)
Here’s a highly-debated topic that deserves its’ own detailed review, whether or not these should be
activated or not. This sensor is focused at a 40-degree angle using an ultra-sonic and visual aids to maintain
stability. It uses defined patterns to help stabilize your drone level. Many of the older apps informed operators to disable the VPS over water. This notification was included so that drones would auto-correct its’ position and climb suddenly. But this is not the case with newer drone models that have these two sensors. Here’s why:
• Moving Water Vs Prop Wash
As a drone moves over water at an average height of 20 feet (over 7 meters), your VPS stands a better chance at recognizing visual landmarks. These can include the edge of the shore-line, beaches, and solid ground. It allows a steady flight that won’t get confused with moving bodies of water so easily. But what happens when you fly your drone with the VPS on if you’re over open water at low altitudes?
This is when a phenomenon called prop wash’ can affect these sensors. The prop wash disturbs these ultrasonic sensors when your drone is around 3-4 feet above the water. The downward rotor airflow causes the surface of the water to radiate outward. Rather than climbing higher to avoid hitting the water, the ultrasonic sensor causes your drone to drop lower. The 40-degree sensor circumference then gets further confused.
It’s been hypothesized that downward visual position sensors are blocked by the water, as it reads height through ultra-sound emissions. Other operators are blaming satellite and GPS connectivity. By turning-off the VPS of both of the downward sensors, you can still maintain VLOS altitude without fighting your drone. This helps to reduce the automatic dipping effect if you are simply hovering. When moving in a direct path,
this problem is eliminated altogether
Windy conditions
It’s never advised to go fly your drone on a windy day, no matter how experienced you are. The problem with wind currents is that they can change suddenly due to hot or cold weather conditions. Another problem is that you cannot see how wind currents are moving and can be unpredictable, just like ocean rip-tides.
Thankfully, many of the newer Go-apps such as UAV Forecast or Hover are free to download. These give instant weather conditions, wind strength, and even ideal altitude for the UAV flight. They also provide helpful information on electromagnetic disturbances that can affect your drone’s GPS signals. Both apps are essential to have and always user-friendly. Anytime you decide to go flying, double-check the weather reports first before making a bad decision.
Sunlight Glare and Water Reflection
Another subject that is seldom mentioned when flying a drone over water is the problem with sunlight and light reflection. Water is an amazing liquid that does appear to be invisible at certain times. It can also be a
highly-reflective surface that bounces light naturally. Your drone most-likely comes with a second visual aid called a DJI vision sensor. This helps your drone sense obstacles and terrain through real-time visual
mapping. But it has one vital flaw, and that is water glare that blinds this sensor instantly. You might like sending out your drone at certain times of the day to the lake or Oceanside. When it comes to a spectacular sunrise or sunset, water will light up due to the angle of the sun. When it does, your drone i flying blind and likely not able to give a reasonable anti-collision response if you are near trees or cliff-sides. This is another reason why your VPS should be switched-off while flying over water.
• ND filters
It’s worth a fair mention to include that any onboard camera used for video also has additional ND filters. This helps with sunlight and glare. It’s not clear whether neutral density or polarizing filters can be used for
the vision sensor underneath your drone? It would make a lot of sense to reduce glare issues by covering this sensor since it uses visual imagery. Yet perhaps this is an issue that has not been fully tested.
Beware of the Birds
Let’s be honest about the problem with birds. They are curious creatures that can be a threat to your drone. Seagulls are notorious for getting too close to your hovering craft. The sound will attract them, and it’s best to get your drone higher ground very quickly. This is especially important when your drone is right over open water.
In fact, avoid all birds if they are present around your location. You don’t want to face fines or charges of animal cruelty if they decided to attack your drone. This also goes for isolated locations at lakes and rivers where overprotective Mommy’ birds are nesting. Hawks, ravens, eagles, and even bats are known to be attracted to your drone.
Just so you know, the fine for killing or injuring an American Bald Eagle can be high! As much as 10,000 US dollars and possible prison time if you get caught buzzing their nest. All operators must stay clear of an eagle nest by 1000 feet away. In general, this should apply to all types of birds for the very same reasoning.
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Visual Line of Sight (VLOS)
You should always maintain a good visual line of sight when your UAV is over the water. This means you need to position yourself where the light allows you to keep a careful eye on its’ location. Any decent drone will have additional software installed that gives you a range that can be controlled. You need to set a limit on how far your fly, no matter what your onboard cameras can see.
• Set your home point
For most of you who might not know, there is something called DJI. It was created by Frank Wang, and he developed Da Jiang Innovations and became what is known as the hobby drone for all flight enthusiasts. This was an added innovation that was built-into a drone, so battery levels and near-collisions were avoided. This automatic feature has extended into adding a distance control or if your drone goes out of range. It’s also a fail-safe feature that can keep your drone from flying off into the sunset.
Most operators will set their home point before take-off, so your drone knows where to return to. Learning to set that home point will save you a lot of money in the long run. If your drone is flashing low battery over the water, or you lose GPS service, this feature is a must.
Beware of GPS Towers
Having plenty of GPS for your drone is great for getting a better position on where your craft is located. Unfortunately for GPS towers, their powerful signal can also work against you. It can interfere with the
drone’s navigation, and your drone may end-up lost in the water. This is another reason why the home point feature should always be set-up before you fly. The newer towers are using stronger signals than ever before. Some of these towers are now already equipped with 5G technology. Save yourself the extra hassle and avoid areas that have GPS towers when flying a drone over water. Magnetic interference is the main reason for drone failure.
Your compass calibration is also something that will be a counter-measure in case of heavy GPS interference. This is for the same reason that you would need to shut-off GPS mode flying between tall buildings. So if you are flying near known GPS towers, you might want to consider switching-off your GPS Mode and enable the Home Point setting.
