Part 107 UAS pilot reported conducting a UAS flight near a law enforcement helipad in a nearby airport's Class D airspace with a LAANC authorization. During the flight; law enforcement officers approached and informed the UAS pilot stating the proper procedure for authorizing the UAS flight was not followed.

Narrative

Chain of Events:On Day 0 I applied for authorization to operate a UAS (drone) in ZZZ Class D airspace to conduct aerial mapping of a building rooftop for Day 15. This is done via the Low Altitude Authorization and Notification Capability (LAANC) system available through several vendors. I filed via Aloft.AI. While preparing my LAANC request; I observed that despite being on the outer area of ZZZ airspace; the area of my operation was a '0 ft LAANC grid' so I needed to request permission to operate a drone at any altitude. This is unusual for most airports; so I investigated further.During my research into the airspace; I observed that the Police Aviation Unit has a helipad across the street from my planned operation (also in Class D airspace); and concluded this helipad is the reason for the LAANC 0 ft grid. I filed a LAANC request for 200 ft AGL altitude in the proposed area of operations. I requested approval for the operation from XA:00 to XI:00 on Day 15.Understanding that there could be low flying helicopter traffic immediately in the vicinity; in my LAANC request Safety Justification comments; I noted the close proximity to the helipad to let ATC know that I was aware of it; and stated that I would use a Visual Observer to maintain the ability to see-and-avoid.I expected some communication or further coordination from ATC given the location; but shortly after I received LAANC approval on the Aloft portal for the operation with no further comments from ATC. I submitted additional requests in the same location; on multiple days from Day 15 to Day 22 and received approval up to 200 ft altitude for each day without comment from ATC.Official FAA guidance on LAANC stresses to drone pilots that they should never call a control tower in regards to airspace authorization; and the LAANC submission page on Aloft states that attempting to call ATC to discuss an authorization may result in automatic rejection for an airspace authorization. Knowing this; I declined to contact ATC to further discuss my operation's proximity to the helipad; trusting that the LAANC request and my comments in it were sufficient notification.On Day 15; with LAANC approval; I operated my UAS at an altitude of 150 ft AGL. At approximately XD:30 local time; during my flight; a police vehicle pulled up to my location and two officers from the Police Aviation Unit approached me. They questioned me why I was operating so close to an active helipad. They were extremely concerned about my drone operation and assumed I had no authorization to be there. I explained that I had LAANC authorization for the area and presented my approval notice to the officers. At that point they explained to me that LAANC authorization is not enough and that I must contact their helipad directly. They asked me how much longer I was going to operate and I gave them the remaining details of my operation. After informing me again that they need a phone call in advance in the future; they left and allowed me to continue my flight; which lasted an additional 5 minutes. Once landed; I received a phone call from ZZZ Airport ATC. They had let me know the police notified ZZZ Airport; and explained to me that their LAANC system does not notify them of the nearby helipad; and that had they understood the proximity of my operation; they likely would have not approved me. They explained that in the future a LAANC approval would be contingent on calling and receiving permission from the Police Department. They also explained that I only had authorization for that day; and did not have authorization for subsequent days despite my Aloft.AI LAANC portal stating I still had authorization. ATC recommended that I call the tower next time I'm operating in the area. We concluded the call with the understanding that for any future operations in the area; I must call ATC and the Police Aviation Unit before I operate.There were no near-misses or conflicts during the operation as the police helicopter was not active throughout the flight; but the interaction greatly concerned me about the current state of LAANC and UAS airspace integration; and left me unclear to what extent I have a responsibility to notify off-airport helipads as a drone pilot.Human Performance Considerations:There is not enough training and not enough resources for drone pilots to understand where a police helipad is in regards to their operation. This helipad is not charted on the Sectional Chart. I only identified the helipad after browsing Google Maps and the Helicopter Route Charts. Part 107 drone training does not make pilots aware that Helicopter Route Charts even exist and I only knew to search this from my Part 61 Private Pilot training. Aloft.AI shows the helipad for informational purposes but offers no other advisories to a drone pilot. Current Part 107 training is insufficient for making drone pilots aware that other sources of helipad locations exist beyond the Sectional Charts. I believe the average drone pilot would have operated in this location without even knowing a helipad exists; as Helicopter Route Charts are not covered in Remote Pilot training or on the Remote Pilot Aeronautical Knowledge Test.The LAANC system keeps drone pilots in the dark too much on ATC's end; and also does not provide enough drone operational information for ATC to make an informed decision. In this case; despite stating in my LAANC request that I was aware of the helipad nearby; I was given approval in advance yet after my flight; told by ATC that had they had the 'full picture' that LAANC did not give them; they would have likely not given approval until I coordinated with Police Aviation. As a drone pilot; I had no way of knowing that this was happening on ATC's end - I simply get an approval email with no comments. A reasonable and informed drone pilot would conclude this means approval to operate with no other restrictions or requirements. This is a safety issue if we are given approval when we shouldn't have received approval without further coordination. The system should be updated to provide a more real-time means of drone pilot and ATC coordination if necessary.Remote Pilots are actively discouraged by the FAA to contact ATC through any method other than the LAANC portal. Knowing this; I stated the proximity of the helipad in my LAANC request yet the system apparently does not alert or call this out to ATC for further consideration. If I had called the tower ahead of time I could have avoided the issue with Police Aviation and it would have given me the opportunity to review safe procedures with ATC to allow for proper separation of potential heli traffic and my drone flight. I chose to follow FAA guidance and not call ATC which led to confusion and a safety issue when my drone was spotted by Police Aviation. There should be better FAA guidance to both drone pilots and ATC that sometimes a phone call to ATC is both warranted and allowed.Drone pilots are also not given clear guidance on what to do when operating near helipads that are not part of the LAANC-enabled airport; even in controlled airspace. I was informed that I should have called Police Aviation directly; yet the helipad's phone number is not available through any official websites; and the helipad is not listed in the FAA Chart Supplement. ATC has much more information and communication with the helipad than I do as a drone pilot; and I believe they should be responsible for coordination and notification once LAANC is approved. I was given a phone number on a business card by the police officer after the fact and told that should be my main way of notifying the helipad. Again; FAA guidance and LAANC documentation strongly discourages pilots to contact ATC; so it is reasonable for a drone pilot to assume they should also not call private helipads if they have airspace approval- drone pilots are given the impression that LAANC takes care of all of this coordination.LAANC fails to give ATC the tools they need to maintain full situational awareness of drones within their airspace. In the manned aircraft environment; all pilots at a towered airport communicate with ATC directly; have radar plus ADS-B; and are made aware of traffic advisories in real-time. With LAANC; ATC only receives the general operating area of the drone; the maximum altitude; and a (large) window timeframe that a flight may occur. LAANC does not inform ATC the current location of the drone; exact takeoff/landing times; or even whether or not a drone is or is not operating in the area. This is a significant safety issue compared to manned aircraft operations where all aircraft have radar separation; and could have caused a collision hazard had a helicopter taken off and an accident chain been allowed to continue.LAANC provides no way for manned aircraft operations (i.e. the Police Aviation Unit) to know that a drone is in their area. ATC is either not encouraged to; or unable to notify helipads within their airspace that a drone operation has been filed nearby via LAANC. The only way that the Police Aviation Unit knew my drone was in the region was due to their own drone detection system they operate. It should not be incumbent on a prior phone call from a drone pilot; or a a police-operated drone detection system to be the only method of the police knowing that my drone was in the area.ATC informed me via a phone call after my flight that I only had approval for Day 15 and no other days. My Aloft.AI LAANC portal still tells me I have approval for additional days. There is therefore some kind of disconnect on approval status between the LAANC service provider and ATC. This is a serious safety issue if a drone pilot can be notified they are approved by the LAANC provider on their end; yet ATC is stating via phone that they are not approved.To summarize; as drone pilots we are given very conflicting guidance by the FAA and ATC themselves on how to best notify ATC of our operation; as well as how to contact other entities like police/hospital helipads that we are operating near the area. The FAA states we should not make phone calls; but ATC and many police helipads have situations that require it. This causes major confusion and is a safety issue for drone pilots nationwide.I would be happy to discuss any detail of this operation further as I am a frequent drone pilot in ZZZ airspace and want to see safe integration of UAS into the national airspace system.