Phantom 4 Pro+ Question on setting Home Point in DJI GO 4...

[svjobeth]

Hi everyone,

I'm a relatively new flyer and very new to the Phantom Pro 4+ AC and the DJI GO 4 app. So far, flights have been good, always LOS and under 200'. The AC has performed well, the only problem being me breaking one of the gimbal lock legs when taking it off of the gimbal ...a new one from Polar Pro is on the way.

I plan to use the AC quite often from my sailboat while the boat is underway or at anchor/moored. (My wife and I are full time live aboard cruising sailors.) When launching the AC from the boat, (all launches will be by hand and landings will be hand catches), when do I set the Home Point to be the location of the RC...prior to launch, or after launch while the AC hovers?

When practicing in the field I've been flying, I've had to set the RC as Home Point after the AC launches and hovers and the app announces "Home Point has been set, please check the map." I then reset the Home Point as the RC, then move a fair distance away, 100' or so, from the launch location while flying. In these instances, when I initiate a RTH, the AC has always landed about 5 feet in front of where I am with the RC. So that's good.

However, when I've set the RC as the Home Point prior to takeoff, the Home Point seems to reset as the GPS launch location once the AC is in the air. Am I missing something on setting and keeping the RC as the Home Point prior to takeoff? Not paying attention to this could be bad if we sail away from the launch location and a RTH initiates with the launch location as the Home Point!

Thanks!

 

[msinger]

When setting the home point to the RC's location, the home point will remain at that location until you reset it again. If you move away from that location, you'll need to reset the home point to the new location of the RC.

 

[svjobeth]

When setting the home point to the RC's location, the home point will remain at that location until you reset it again. If you move away from that location, you'll need to reset the home point to the new location of the RC.

Ah...that explains a lot. Thank you!

 

[John Locke]

To elaborate, the homepoint automatically sets when your craft gets more than 10 satellite connections to the craft. To mitigate risk, you should not take off until you have the green "safe to fly" indication, at which time you have enough satellites and the DJI lady has announced, "homepoint has been set."

If you are underway at sea in your boat while flying, and you wish to reset the homepoint, the GPS receiver in the P4P+ controller will be the new homepoint, not the craft. You should practice that on land before trying at sea, IMO.

If you have any problems with homepoint setting, as backup make sure you understand the radar screen on your screen so you can get back home safely. However that only works while you have a connection with the craft.

I don't recommend using the RTH button while at sea, as it might land in the water if you don't retake control soon enough. I could see confusion doing that if you relied on RTH in fog where you lost VLOS of the craft, and you drifted from the original homepoint. There is no option in the GO4 app to RTH and not land upon signal loss, but you can retake control when a connection is re-established, assuming your are within radio range while at sea. There is an option to hover upon signal loss, but that's not recommended to use at sea. If auto RTH were to ever be enabled at sea, you better be near the original home point location in your boat so you can retake control before it lands in the water.

BTW, flying 5.8Ghz AUTO gives you the best range, and using a windsurfer on the antennas gives you even more range, over 4mi at sea, assuming you are pointing the parabolic dish in the general direction of the craft.

 

[svjobeth]

To elaborate, the homepoint automatically sets when your craft gets more than 10 satellite connections to the craft. To mitigate risk, you should not take off until you have the green "safe to fly" indication, at which time you have enough satellites and the DJI lady has announced, "homepoint has been set."

If you are underway at sea in your boat while flying, and you wish to reset the homepoint, the GPS receiver in the P4P+ controller will be the new homepoint, not the craft. You should practice that on land before trying at sea, IMO.

If you have any problems with homepoint setting, as backup make sure you understand the radar screen on your screen so you can get back home safely. However that only works while you have a connection with the craft.

I don't recommend using the RTH button while at sea, as it might land in the water if you don't retake control soon enough. I could see confusion doing that if you relied on RTH in fog where you lost VLOS of the craft, and you drifted from the original homepoint. There is no option in the GO4 app to RTH and not land upon signal loss, but you can retake control when a connection is re-established, assuming your are within radio range while at sea. There is an option to hover upon signal loss, but that's not recommended to use at sea. If auto RTH were to ever be enabled at sea, you better be near the original home point location in your boat so you can retake control before it lands in the water.

BTW, flying 5.8Ghz AUTO gives you the best range, and using a windsurfer on the antennas gives you even more range, over 4mi at sea, assuming you are pointing the parabolic dish in the general direction of the craft.

Thanks much John -

The boat is laid up for repairs at the moment, courtesy of Hurricane Irma...we're ashore for at least another six months or so. I'm practicing in the local field I've been flying in, so I'll have plenty of flight practice time over land before we're back on the boat. So far, setting the RC as the Home Point is working well. And yes, I do understand the Home Point is the GPS receiver in the RC, and not the AC.

My planned flights from our boat would be in fairly close range to our boat, or others if we're sailing with another boat...probably on the order of a mile or so, max. The end goal in shooting from the boat is getting footage and images of our boat under sail, or using the drone to scout passes in reefs, harbor channels, anchorages, etc.

I've not played around with the radar function on the app, other than to open it and look at it, but I can't imagine it's much different than ours on the boat.

Thanks -

 

[Meta4]

So far, setting the RC as the Home Point is working well.

There are two options for resetting the homepoint.
You know about setting your current location as home or you can set the current location of the drone as home.
If you are on a moving boat, you won't be wanting the Phantom to come back to the exact point where you last set home.
If you are flying in sight of the boat, resetting home to the Phantom's current location may be good enough.
The main point is that you don't fly along while sailing and get to a point where the Phantom thinks it is miles from home (where it took off) and wants to RTH because it only has enough battery to get back.
Keeping the home point somewhere close will prevent that from happening.

I've not played around with the radar function on the app, other than to open it and look at it, but I can't imagine it's much different than ours on the boat.

The radar display is very useful and quite intuitive.
It shows you where to look to find the drone as well as which way it is pointing.
Next time you fly, try sending it out 50 ft and rotate the aircraft with the left stick while watching the radar.

 

[svjobeth]

There are two options for resetting the homepoint.
You know about setting your current location as home or you can set the current location of the drone as home.
If you are on a moving boat, you won't be wanting the Phantom to come back to the exact point where you last set home.
If you are flying in sight of the boat, resetting home to the Phantom's current location may be good enough.
The main point is that you don't fly along while sailing and get to a point where the Phantom thinks it is miles from home (where it took off) and wants to RTH because it only has enough battery to get back.
Keeping the home point somewhere close will prevent that from happening.

The radar display is very useful and quite intuitive.
It shows you where to look to find the drone as well as which way it is pointing.
Next time you fly, try sending it out 50 ft and rotate the aircraft with the left stick while watching the radar.

Thanks - I plan to be very conservative when flying off the boat. I tend to watch the battery now. Off the boat, I would likely start planning the return when at 40% or so for some margin...and launching with a full battery! We don't need long minutes of sailing footage, just a few minutes from many angles. I envision the drone being within a mile much of the time when flown off the boat, and often, closer than that. The exception would be flying when scouting ahead and that would take vigilance.

I flew this afternoon and played with the radar. It is intuitive, much more so than the one on the boat and the functionality of it is a different. It is indeed very useful, and pretty straightforward.

Incidentally, while playing with the radar, I discovered the forward and rear sensors can apparently be fooled by direct sunlight. I was flying above the tree tops (about 100' AGL) in P mode. When the drone came into direct orientation with the afternoon sun, it came to screeching halt and hover, with the obstacle sensors beeping away and a pop-up telling me "Braking; release sticks to center position!" or something to that effect. The exact same thing happened flying in reverse. I droped down below tree tops and into shadows, at around 40', and the drone flew without interruptions.

 

[Meta4]

I discovered the forward and rear sensors can apparently be fooled by direct sunlight.

You sometimes hear of Phantoms mysteriously climbing high in RTH and it's caused by the Phantom trying to avoid hitting the afternoon sun.
Just another little trick to remember.

 

[svjobeth]

You sometimes hear of Phantoms mysteriously climbing high in RTH and it's caused by the Phantom trying to avoid hitting the afternoon sun.
Just another little trick to remember.

LOL, it's good to know. I was confused for a bit as to what it was 'seeing' in it's path!

 

[John Locke]

The end goal in shooting from the boat is getting footage and images of our boat under sail, or using the drone to scout passes in reefs, harbor channels, anchorages, etc.

You'll want to play with active track I'm sure, allowing it to track your sailboat this summer. With sailboats having a top speed of about 15mph, the speed of active tracks should be adequate to follow your sailboat. I think the P4P can do about 15mph or so in active track mode. I don't use it that much, but I think that's about the top speed it can do to keep the subject in the camera.

You'll want to learn how to hand launch, that will be essential when launching from a sailboat. You'll likely want to get a harness to help you with the RC, allowing you go confidently operate the launch command and activation slider with one hand, usually the left hand, while you hold the craft with the right hand as you provide the ascend command with the left stick.

Catching the craft is easier IMO, but doing it with a moving boat bobbing up and down adds another dynamic I haven't experienced. So in that case launching may be easier.

Landing with 25% is a good target. You absolutely can't afford to let the craft get down the 10%. That's when the craft starts to descend and land where it's at, which isn't good when over water. Although you can give it ascend command to prevent the craft from descending into the water, catching it is more tricky because it won't keep a steady hover to allow it to be safely grabbed. The added navigation duty of UP LEFT STICK to prevent descending make it way more risky, something you should avoid having to do, like the plague. Just be careful when you fly in wind, always fly upwind if possible.

You can measure the wind speed by letting the craft drift in ATT mode for about 20-30 seconds, until the craft quits accelerating. At that point, that speed will be your wind speed. Substract that from a 42mph top drone speed, and you'll know how fast you can get home if flying downwind. If 20mph is your top net speed, allow 3min flight time per mile to return to home. You may have speed sensing electronics in your sailboat that will help you predict the impact of wind to retrieve your drone.

 

[svjobeth]

You'll want to play with active track I'm sure, allowing it to track your sailboat this summer. With sailboats having a top speed of about 15mph, the speed of active tracks should be adequate to follow your sailboat. I think the P4P can do about 15mph or so in active track mode. I don't use it that much, but I think that's about the top speed it can do to keep the subject in the camera.

You'll want to learn how to hand launch, that will be essential when launching from a sailboat. You'll likely want to get a harness to help you with the RC, allowing you go confidently operate the launch command and activation slider with one hand, usually the left hand, while you hold the craft with the right hand as you provide the ascend command with the left stick.

Catching the craft is easier IMO, but doing it with a moving boat bobbing up and down adds another dynamic I haven't experienced. So in that case launching may be easier.

Landing with 25% is a good target. You absolutely can't afford to let the craft get down the 10%. That's when the craft starts to descend and land where it's at, which isn't good when over water. Although you can give it ascend command to prevent the craft from descending into the water, catching it is more tricky because it won't keep a steady hover to allow it to be safely grabbed. The added navigation duty of UP LEFT STICK to prevent descending make it way more risky, something you should avoid having to do, like the plague. Just be careful when you fly in wind, always fly upwind if possible.

You can measure the wind speed by letting the craft drift in ATT mode for about 20-30 seconds, until the craft quits accelerating. At that point, that speed will be your wind speed. Substract that from a 42mph top drone speed, and you'll know how fast you can get home if flying downwind. If 20mph is your top net speed, allow 3min flight time per mile to return to home. You may have speed sensing electronics in your sailboat that will help you predict the impact of wind to retrieve your drone.

LOL, if we're going 15mph, we're out of control! She's a heavy displacement ocean voyaging boat. Our ideal speed is around the 5.5 knot mark, (a little over 6mph), and our theoretical hull speed - the fastest we can go before we would begin to 'plane' over the water - is around 7knots - or 8mph. The fastest I ever recall seeing was in rough weather and big waves when we would hit around 11 knots surfing down the faces of some of those big waves - very intense - and we were very concerned about the boat broaching at the bottom of the wave - turning side to the seas and potentially rolling - not a good thing! The P4P will have no trouble keeping up with us!

I/we are practicing hand launching/catching ashore. No issues thus far. and we do have wind speed/direction instruments aboard, fitted at the masthead, so about 55' AWL. We can also measure the apparent wind speed, apparent/true wind angle, etc. And, we can measure speed through the water with a knotmeter, (a paddle wheel transducer on the bottom of the boat), or speed over the ground with GPS.

 

[John Locke]

Catching the craft is easier IMO, but doing it with a moving boat bobbing up and down adds another dynamic I haven't experienced. So in that case launching may be easier.

I forgot to add that hand catching the craft on land is relatively easy. When you grab the craft while it's sitting in a hover, just hold the craft in place, then push the left stick down. After the flight controller senses the craft hasn't moved for 3 seconds, the motors shut off. HOWEVER..... if you're on a bobbing boat, rocking back and forth, you can't keep the craft still for 3 seconds because the boat is moving around, so the motors may not turn off like normal. If you experience that situation, you'll need to be prepared to give a CSC command. That command requires both sticks pushed down and inward, which will shut down the motors immediately in any circumstance, moving or not. To do that command normally requires both hands with two sticks, but if you catch the craft with the right hand you only have your left hand to execute the CSC. With practice you may be able to master a TWO STICK CSC command with your left hand while you hold the craft with the right hand, assuming you have a harness on to help hold your controller. This is something to practice on land, in preparation, if you need it at sea. Optionally you can get help from a second person.

Here's a video that demonstrates this problem while on a boat.

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[svjobeth]

I forgot to add, that catching on land is easy. When you grab the craft while it's sitting in a hover, just hold the craft in place while you give push the left stick down. After the flight controller senses the craft hasn't moved for 3 seconds, the motors shut off. HOWEVER..... if you're on a bobbing boat, rocking back and forth, you can't keep the craft still for 3 seconds because the boat is moving around. If you experience that situation, you'll need to be prepared to give a CSC command. That command requires both sticks pushed down and inward, which will shut down the motors immediately in any circumstance, moving or not. To do that command you usually need both hands, so if you catch with the right hand you only have your left hand to execute the CSC. With practice you may be able to do a TWO STICK CSC command with your left hand while you hold the craft with the right hand, assuming you have a harness on to help hold your controller. This is something to practice on land, in preparation, if you need it at sea.

Here's a video that demonstrates this problem while on a boat.

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Way ahead of you - already practicing the one hand CSC on land. I have the lanyard for the remote, but not the harness. I'll have to look and see if I can find a way to incorporate the remote lanyard (or the RC itself) into my safety harness already being worn on the boat.

Interesting clip - thanks!

 

[John Locke]

Way ahead of you - already practicing the one hand CSC on land. I have the lanyard for the remote, but not the harness. I'll have to look and see if I can find a way to incorporate the remote lanyard (or the RC itself) into my safety harness already being worn on the boat.

Interesting clip - thanks!

Perfect, as long as you're aware of this nuance of hand catching in a boat, you're good. This guy in the video is an experienced drone flyer, and he apparently didn't know.

 

[svjobeth]

Perfect, as long as you're aware of this nuance of hand catching in a boat, you're good. This guy in the video is an experienced drone flyer, and he apparently didn't know.

I saw that. Both my wife and I have been sailing for 30+ years, each. We've spent lots of time figuring out how to get things on and off the boat safely and have had our share of trial and error. Plus, I've been watching lots of other pilot videos on boat launching/recovery. One mistake I've seen some pilots make is catch with the boat stopped. In very calm conditions, I believe that can work. However, if there's any sort of sea running, the boat will behave better if it's moving slowly forward. Otherwise, it will likely roll and yaw, complicating the execution of the catch. With some slow forward motion, the boat may still roll, but the helmsman will have a modicum of control.

 

[John Locke]

I recommend wearing gloves when catching, especially a moving drone which increases risk, really important if it's a second person catching. The gloves can't be too thick, losing dexterity of the grab. But they can't be too thin either, to protect the hand well in a mishap. They also need to have the finger tips covered, not fingerless gloves. The video shows the guy with no gloves, which adds risk.

 

[svjobeth]

I recommend wearing gloves when catching, especially a moving drone which increases risk, really important if it's a second person catching. The gloves can't be too thick, losing dexterity of the grab. But they can't be too thin either, to protect the hand well in a mishap. They also need to have the finger tips covered, not fingerless gloves. The video shows the guy with no gloves, which adds risk.

I hadn't considered gloves. We have 'no-cut' fishing gloves that would work well. In addition to be the no-cut fabric, they're also 'grippy.' Fantastic idea though.

 

[John Locke]

We have 'no-cut' fishing gloves that would work well.

That sounds perfect if they aren't too clumsey/bulky, etc.

 

[svjobeth]

They're a bit on the bulky side, but they're not like winter gloves by any stretch. Very similar to these:

https://www.amazon.com/Rapala-RAPFIGL-P-Fillet-Glove/dp/B009SYTT10