Hi everyone, I'm new to this thread. Was hoping to get some insight on using the Phantom 4 Pro for building inspections, especially high-rise ones (>100m).

I had my first taste of trying out the Phantom 4 Pro for this feature, and i faced many problems. Some of the problems include:

1) Weak GPS Signal : I was in a fairly open area, and the GPS satellites should be good (i had between 9 to 12 satellites), but yet it showed me this warning. Why is this so?

- What tips would you have for me to be able to get a stronger GPS signal? Any best practices to recommend?  

2) Weak RC Transmission Signal : I keep losing and intermittently regaining the RC transmission signal even though the drone was less than 1km away from the transmitter. Why is this so?

- How can we reduce the onset of this weak signal? How do i select the frequency band for more stable transmission signals?

3) Very Strong Winds : My P4 Pro was blown around like a leaf; the weather forecast in the area stated winds were around 20mph and gusting to 25mph. I thought the drone would be able to handle it, but it was apparent that it couldnt.

- What features can i change on my drone in order for it to be able to withstand the winds better? How do i make it more stable in flight ? How do i make it drift lesser, especially when it is close to the building facade?

4) Is anyone using any software for facade and building inspection that works very well for you? At this point, any form of help with be useful for me to focus more on the quality of the pictures taken rather than having to fight with the elements and taking pictures at the same time.

Hope i can receive some useful and valuable input from the drone experts in this forum.

Thank you so much in advance for your help !

Hi. Thank you for reaching out to DJI Forum. With regards to this matters. I hope that our valued DJI co pilots can provide you the best information with regards to this concern. First, when flying the drone in a location with a lot of interference like metal structures. This may cause connectivity issue during flight and weakens the transmission signals from the drone to the remote controller. Second, the DJI Phantom 4 Pro has a maximum wind resistance of 10 m/s. Lastly I will be providing and official DJI tutorial video on the proper way to use the antennas of your remote controller. Thank you.

1) Weak GPS Signal : I was in a fairly open area, and the GPS satellites should be good (i had between 9 to 12 satellites), but yet it showed me this warning. Why is this so?

OK, I will give this a go. If you are examing the facade of the building, and it is quite tall, then it will screen approximately half the sky from the GPS satellites, particularly if you are close to the building. This is common, and is often called the 'urban canyon effect'. Another way of putting this is that the aircraft needs a half-sphere of visible sky to geet a good GPS solution, but up close to a tall building, it will only see a quarter of a sphere at best.

One possible solution might be to use a P4RTK aircraft, where there is a separate reference transmitter nearby. The P4RTK guys might better advise you on this, but otherwise there is no way to improve the GPS satellite reception.

2) Weak RC Transmission Signal : I keep losing and intermittently regaining the RC transmission signal even though the drone was less than 1km away from the transmitter. Why is this so?

Without knowing where you are located at the time, while controlling the aircraft, this is hard to diagnose. But if you are at the base of the building and the aircraft is mostly directly above you, then you are in the wrst possible position to get strong control signals. You need to pay attention to the position of the antennas on the RC unit, pointing the flat side towards the aircraft. However the antennba on the aircraft itself is in the legs, and cannot be point very well towards the RC unit, and there is the source of the problem. There are various after-market devices designed to improve the transmission/reception of signals, but you still have the issue of the aircraft antennas not being in the correct position. The only suggestion I can make is to position yourself a bit further away from the building, perhaps even on an upper level floor of a building adjacent.

One other point, while doing this kind of work, NEVER fly the aircraft around the side or the back side of the building. If you do so, it will lose signal and try to return home THROUGH the building. Always keep the aircraft in sight.

3) Very Strong Winds : My P4 Pro was blown around like a leaf; the weather forecast in the area stated winds were around 20mph and gusting to 25mph. I thought the drone would be able to handle it, but it was apparent that it couldnt.

Weather forecasts should be treated as a guide only, and not absolute. In addition, the winds in a canyon of high rise buildings will bear no resemblence to the forecast anyway, and can be completely different around each building. Also, winds at higher altitudes can be quite strong compered to ground level. The only suggestion I have here is that the P4 aircraft are quite good performers in stronger winds, so you might have to choose your days more carefully.

4) Is anyone using any software for facade and building inspection that works very well for you? At this point, any form of help with be useful for me to focus more on the quality of the pictures taken rather than having to fight with the elements and taking pictures at the same time.

As far as I am aware, there is no software designed for this task, other members may know different. If you need to concentrate on the pictures and not the flying, then perhaps a different aircraft is the answer. You could try a DJI Inspire for the task, as it can be operated by two people, one flying and the other operating the camera. Maybe hire one to see if it works any better for you.

Others may question whether what you propose to do is a safe procedure. One of the most common rules of flying drones is not to fly them over people, and I imagine it would be difficult to avoid doing so in these circumstances.

Geebax,  Awesome write-up!   The only thing I could add about the wind, is that on the windward side of a building you will encounter very significant updrafts and they can be amplified by the velocity of the oncoming wind and conversely, on the leeward side of the building you will encounter equally significant downdrafts that could overcome the lift generated by the props and drive your drone right into the ground in  very severe cases.  Wind shear is a related phenomenon and has been know to drive a jumbo jet to a bitter end at low altitudes.   Also, overcoming the effects of the wind will very much increase your power consumption and reduce your flight times.  You should be cautioned to stay well clear of structures like tall buildings for those reasons.

I have the P4P Plus, I was worried with the same message about GPS signal weak when I was doing a video of a construction site, I was less that 10 meters away from a block of apartment buildings and flying over the site to give an aerial view of the footings being dug, and then finally the roof trusses being erected, I was concerned so for safety reasons I put it in for a service and check over as I was new to drones but not new to flying, the report came back that following extensive testing 6 - 9 satellites was normal for the environment I was flying around in.

You will always have more winds near a building.  You guys need an Alientech booster for the ultimate signal.

https://alienth.cn/products/alientech-dou-panel-antenna-for-dji-drones-that-suitable-for-spark-mavic-phantom-3a-3p-4a-4p-v2-inspire-1-2-matric-200-600-agras-mg-is?_pos=3&_sid=bb53b095e&_ss=r&variant=13604876582987

I just think it's more of a hassle but the range of the P4PV2.0 is crap in a high-interference environment.