Understanding the ASPRS Positional Accuracy Standards: Evolution, Impact, and What’s New

Author: Joey Desjardins, Account Manager, AeroTech Mapping

Let’s start with something you probably weren’t expecting to hear from someone who works for an Aerial Mapping company.

Every surveying firm should own a drone.

They enable you to conduct site reconnaissance, perform inspections, and capture orthophotos to help you provide robust deliverables. This makes it easier for both the office staff and clients to understand the data vs. dots and lines with point codes and surface models on a black screen.

There are a wide variety of options for whether you’re getting your first drone, such as the DJI Mavic 3 Enterprise, which starts at $3,700 (up to $8,000 with RTK and D2 RTK base, or save $3,600 by pairing with your internet base capable GNSS), to mid-tier options like the $34,000+ M350 with P1 and L2 (45MP camera and 1.2MM points per second LiDAR sensor) or fixed wing options such as Quantum Systems’ Trinity Pro with the Sony RXI RII camera and Qube 240 LiDAR sensor for about $86,000 for those more proficient, and even $100,000+ rigs with advanced sensors for companies going all in.

The key, however, is determining which mapping missions are suitable for self-performing with a drone vs. hiring an aerial mapping firm with manned aircraft. We’ll explore the five key criteria to help you decide which approach best suits your project needs: flight restrictions, schedule, scope and capabilities, cost, and convenience. Additionally, to keep things light, I’ve included some AI generated art proving, while cool, AI isn’t quite ready to take over (tough to do when it has a hard time spelling).

Flight Restrictions

One of the primary considerations when choosing between drones and manned aircraft is the airspace over the project location. Drones are subject to a myriad of restrictions that can limit where they can operate. For instance, flying drones in controlled airspace, such as near airports (Class B, C, D, & E airspace depending on the size of the airport and traffic), requires Air Traffic Control (ATC) approval which can be obtained through Low Altitude Authorization and Notification Capability (LAANC). This could be a lofty task depending on the specific location and proximity to runways. Other sites such as military installations, and critical infrastructure sites, including nuclear power plants and chemical facilities can be nearly impossible due to strict regulations. Additionally, drones are not allowed in national parks, or wildlife refuges (due to safety concerns and wildlife protection) without approval of the Superintendent or a Special Use Permit (typically given for search & rescue, research, or fire safety). Both of which are highly unlikely to obtain.

While it is possible to obtain special permissions for some of these areas, the process can be complex and time-consuming. Manned aircraft, on the other hand, generally face fewer restrictions and mainly just requires communication and approval from ATC during the flight. This allows manned aircraft to be a better option for projects in areas where drone access is heavily restricted or unfeasible.

When working on federal projects, drone approval often depends more on the hardware and software than the airspace itself. Before conducting drone operations for federal agencies, it’s crucial to understand two key compliance standards: the National Defense Authorization Act (NDAA) and the Defense Innovation Unit’s (DIU) Blue sUAS Cleared Drone List (Blue List).

The NDAA sets forth regulations to ensure the security of the U.S. defense supply chain, particularly concerning Unmanned Aerial Systems (UAS). Specifically, Section 848 of the Fiscal Year 2020 NDAA prohibits the Department of Defense (DoD) from procuring drones manufactured in a “covered foreign country” (notably China) or those containing components like flight controllers, radios, data transmission devices, cameras, gimbals, ground control systems, or operating software from these countries or companies based in these countries. In 2022, Congress updated the list of countries to include Russia, Iran, and North Korea. This has also been extended to the private sector working under federally funded contracts. This compliance ensures that drones used for and by federal agencies are free from potential foreign interference or data security risks.

The DIU’s Blue List is a subset of NDAA-compliant drones, hardware, and software specifically verified by the DIU to meet NDAA compliance and assessed to meet the DoD’s cyber security requirements, such as being completely offline. Drones on this list undergo comprehensive evaluations to ensure they are secure, reliable, and suitable for military use. The Blue UAS program streamlines the approval process, allowing military units to rapidly deploy trusted drone technology without compromising security. Blue List is not explicitly required for DoD purchase. However, products on the Blue List do not require an Exception to Policy (ETP) and are updated more frequently than traditional Programs of Record (POR), making them much easier to be approved for purchase and use on DoD projects. You can find the products on the Blue List on the DIU’s website.

A new initiative is the Association for Unmanned Vehicle Systems International’s (AUVSI) Green UAS Certification, which serves as a pathway for drones that are not yet Blue UAS certified but meet initial security and compliance benchmarks set by the DoD. This list allows commercial drone manufacturers to demonstrate their security measures and capabilities before undergoing the full vetting process for the Blue List. While there are no specific agencies requiring Green List products, manufacturers with this certification are better positioned to gain future Blue List approval.

Schedule

In some cases, self-performing with a drone can offer a significant advantage in terms of flexibility and timeline of acquisition. Drones can be deployed as soon as you’re on-site, allowing for rapid data collection and potentially quicker turnaround times for projects with urgent deadlines. For simpler projects, processing and mapping can often be completed in just a few days after the flight.

Manned aircraft, however, typically have a longer lead time. For example, AeroTech Mapping can have a plane scheduled to be on-site as fast as 48 hours from receiving the Notice to Proceed (NTP) or within one week at the latest. Smaller projects tend to be delivered 10-12 business days after a successful flight and receipt of control. Aerial Mapping firms with more dedicated resources and expertise tend to have faster turnaround times on larger, more complex projects than the turnaround times of firms with smaller, less experienced teams.

Weather conditions also affect scheduling. Drones are less susceptible to weather-related delays, such as winds at higher altitudes or low-altitude cloud coverage. They are, however, much more susceptible to winds at low altitudes. The Mavic 3E and WingtraOne have a maximum sustained wind tolerance of just under 27 mph while flying (19 mph on the ground during takeoff and landing for the WingtraOne). Neither drones nor manned aircraft are able to complete aerial mapping missions in severe weather like rain and fog. Additionally, drones are only affected by the weather on-site, whereas manned aircraft are affected by the weather where the aircraft is stationed and the weather en route to the project site. The weather at a project location could be perfect, but if there are 30 mph winds at the airport or a rainstorm between the aircraft and the project, the site will not be flown that day.

Scope and Capabilities

What are the required deliverables for your project? What is the size of the area of interest? The scope of your project and the capabilities of your drone can be the deciding factor on whether to self-perform or partner with an aerial mapping firm. Drones are well-suited for high-resolution imagery, given they fly at much lower altitudes (sub 400ft AGL vs 1,500-4,000ft AGL). The sensors used and altitude flown by manned aircraft are capable of producing imagery with Ground Sample Distance (GSD) as tight as .15’. Projects requiring tighter GSD are better suited for drones. This is also why the size of the project impacts the decision to use a drone or a manned aircraft. Drones have varying flight times and camera sensor qualities. Drones carrying cameras with lower megapixels (Mavic 3E – 20mp) need to fly at a lower altitude than ones with higher megapixels (Quantum Systems Phase One P5 – 128mp) to capture the same GSD. Lower altitudes mean less coverage, more aerial control panels (due to more images to be tied together), and more airtime. Larger project sites with a lower quality camera will take much more time to fly. Each system has its own project size threshold where manned aircraft would be a better fit.

Not only is there a relationship between the size of the project and the camera specs when determining which is best for an aerial mapping project, but also the battery specs of the drone. Each platform’s specifications include a flight time and the approximate area it can cover in a single flight. For example, the Mavic 3E RTK has a flight time of 45 minutes and boasts a single flight survey area of a tad short of 500 acres in a single flight (20MP camera, and 5cm GSD with 80% front and 60% side overlap at 15m/s). A fixed-wing drone such as the WingtraOne MAP has a maximum flight time of 59 minutes, can capture the same resolution at a higher altitude because of its 61MP camera, a slightly higher rate of speed (16 m/s), and covers up to 1140 acres in a single flight (890 acres with LiDAR flown separately from photography). In addition to the field time determined by the size and capabilities of the drone, office time increases due to the number of images to be processed and mapping to be compiled. Each system has a threshold where manned aircraft is more cost-effective. This is determined not only by the drone specifications but also by the capabilities of the firm processing the data and generating the deliverables (not to mention the specifications of the computers handling the processing and mapping).

Both are well suited for design scale mapping (typically 1” = 40’ scale with 1’ contours). Manned aircraft are able to efficiently capture data suitable for mapping scales starting at 1” = 10’ and contours at tight as .5’. Projects requiring tighter scales or contours are better suited for drones.

Some projects go beyond the typical aerial mapping deliverables. Select drones provide payload flexibility, giving users the ability to capture all sorts of data, such as thermal, video, and oblique imagery, that wouldn’t otherwise be captured by manned aircraft.

One payload option available both to select drones and manned aircraft is LiDAR (Light Detection and Ranging). LiDAR sensors produce millions of points per second via a refracted invisible laser beam that results in a point cloud of the area of interest. LiDAR sensors with multiple returns are also able to penetrate through varying levels of vegetation, which gives more accurate ground elevations in areas where the ground isn’t visible in the imagery. They also provide more accurate vertical data on hardscape vs traditional photogrammetry. Entry-level drones tend not to have LiDAR capabilities like mid-tier and high-end systems. Projects with LiDAR requirements, or those that could benefit based on the terrain/vegetation, may be better suited for manned aircraft depending on the configuration of the drone hardware owned by the surveying firm.

Cost

Controlling cost is a key factor in not only being selected for a job but also in the profitability of the job. Selecting the right approach will help win more projects and help complete them in a profitable manner. The costs associated to the flight portion tend to be similar across project sizes under 500 acres as most commercial drones can cover large areas in a single flight as discussed above. The difference in the field & acquisition cost lies in the amount of ground control targets/photo ID points collected and the time to generate the deliverables.

Let’s look at a breakdown of a 5-acre commercial site rich with detail such as parking striping, buildings, vegetation, etc. and what it would take to produce a Design Scale map (1” = 40’ scale, 1’ contours, DTM points and breaklines).

If we use a billable field rate of $350 per hour and a billable office rate of $175 per hour (region specific), the unmanned approach would run about $2,100 – $2,975, including the billable survey fee of $700 – $1,050 to set panels. ATM charges about $2,500 – $3,500 for similar projects. In this case, self-performing with a drone would likely be more profitable than hiring an aerial firm.

Let’s use an example for the same type of site with the same deliverables but covering 40 acres.

Using the same billable rates, the unmanned approach would run $9,450 – $10,850, including the billable survey fee of $1,050 – $1,400 to set panels. ATM charges about $5,000-$7,000 for similar projects. In this case, it could be more profitable, save the surveyor time, and potentially be a lower total job fee.

Keep in mind that Raw Data Processing and Deliverable Generation times vary based on a few factors. First, Raw Data Processing can occur after business hours. Second, the time can vary based on the computing power of the workstation/cloud processing service and the specific software used. Third, manual vs automated extraction workflows greatly impact the amount of processing time depending on the site, data quality, and the specific deliverables.

Convenience

The last criterion to consider when choosing between self-performing with drones or hiring an aerial mapping firm is convenience. Operating drones in-house provides greater control over timelines and execution. However, it also requires dedicating hours to flight planning, approvals, field time completing the flights, office time processing and generating the deliverables, detracting from other revenue-generating activities.

Subcontracting to an aerial mapping firm can alleviate these burdens and bring specialized expertise and resources to handle projects more effectively and efficiently.

In the example above, hiring an aerial firm on a 5-acre project gives the surveyor 4 – 8 hours back, which has varying levels of value depending on the surveyor’s workload. On the 40-acre project, the survey gets 44 – 51 hours back, adding over a week of productivity back to their life.

AeroTech Mapping’s Cloud to CAD Service

Even after considering each of these criteria, some projects may still fall between self-performing, and hiring an aerial firm. What if you have a tight flight window, can produce an Orthophoto and Point Cloud/Digital Surface Model (DSM), but don’t have the time or expertise to produce the deliverables? AeroTech Mapping offers a hybrid solution known as “Cloud to CAD”. In this scenario, clients self-perform the flight and handle the initial processing to produce the ortho and point cloud, usually within 24 hours of a successful flight. AeroTech then takes over to produce the deliverables with a turnaround time of 5-12 business days, depending on the project scope and expedited service.

This approach is particularly beneficial when tight flight windows or rapid turnaround times are required. It allows firms to leverage the advantages of both in-house operations and professional mapping services. Clients who opt for this method might choose it to meet urgent deadlines, achieve higher-resolution imagery, or manage an understaffed office with a backlog of tasks. The cost savings and efficiency of this model make it an appealing choice for many projects.

Mobile Mapping Cloud to CAD project

Conclusion

Choosing between self-performing an aerial mapping project with a drone or using your aerial partner depends on a variety of factors. Flight restrictions, project schedule, scope and capabilities, cost, and convenience all influence this decision. Drones offer flexibility, speed, and cost-efficiency for smaller or less restricted projects, while manned aircraft provide a broader operational range and specialized capabilities for larger or more complex tasks. AeroTech’s Cloud to CAD option presents a hybrid approach that can offer the best of both worlds. By carefully evaluating these criteria, your firm can make an informed decision that aligns with your project requirements and objectives, ensuring successful and profitable projects.

Sources

• Low Altitude Authorization and Notification Capability: LAANC
• Permitting required for drone use in National Parks and Wildlife Refuges: National Park Service – Unmanned Aircraft in the National Parks, Flying Drones in National Parks and National Forests: Updated Guidelines
• NDAA vs. Blue List vs. Green List: Defense Innovation Unit Blue UAS, AUVSI Green UAS,  A simple guide to understanding Blue UAS vs NDAA Compliant vs American-Made drone requirements in 2024
• DJI Specifications: DJI Enterprise
• Wingtra Specifications: WingtraOne
• Quantum Specifications: Trinity Pro

Author: Mike Dauer, Account Manager, AeroTech Mapping

Efforts to ban 100 octane Low Lead (100LL) aviation fuel, commonly used in piston-engine aircraft, are gaining momentum across the U.S. This leaded fuel, which powers a significant portion of the general aviation fleet in the U.S., has become the target of regulators and environmental advocates. Several states and local governments have already implemented bans on the sale of leaded aviation fuel, including Santa Clara County, California which banned 100LL sales at local airports such as Ried-Hillview in 2022. On a larger scale, Washington State is considering legislation (H.B. 1554) to phase out 100LL by 2030​. These efforts have prompted significant pushback from aviation industry stakeholders, including the Aircraft Owners and Pilots Association (AOPA), which argues that banning 100LL without an accessible replacement could ground an estimated 167,000 aircraft with piston-engine aircraft that rely on 100LL for safe operation (including those most commonly used for aerial mapping).  In this article, we’ll discuss why this is happening, what the current proposals are, issues with the proposals, and potential solutions.

Why the bans?

The movement to phase out 100LL is driven by growing concerns about the public health impact of lead exposure near airports that commonly service piston-engine aircraft. Lead is a neurotoxin that has well-documented detrimental effects (particularly on children), such as neurological damage, cognitive impairment, lower IQ, and cardiovascular issues in adults. According to a Santa Clara County study conducted at Reid-Hillview Airport, communities around airports experience higher levels of lead exposure. This study revealed that blood lead levels in children near the airport were higher than those in Flint, Michigan, during its water contamination crisis.  The Centers for Disease Control and Prevention (CDC) and other health organizations emphasize that there is no safe level of lead exposure.  Piston-engine aircraft are the largest source of airborne lead emissions in the U.S., contributing about 70% of lead pollution across the country. Eliminating lead from automotive gasoline in the 1970s drastically reduced national lead levels, but aviation fuel remains a major source of this harmful pollutant.

Current alternatives

In response to these health concerns, the Federal Aviation Administration (FAA) and fuel manufacturers are exploring and promoting alternatives to 100LL.  The most notable being UL94 (produced by Swift Fuels), an unleaded avgas designed for lower-compression piston engines that do not require higher-octane.  UL94 is currently available at many airports and eliminates lead emissions entirely, making it a far safer choice for these types of aircraft.  In states like California, where bans have already been implemented, UL94 is being adopted to meet regulatory requirements. Swift Fuels, the producer of UL94, has been expanding its distribution network across the U.S., with more airports starting to offer it as an alternative.  The FAA, along with various stakeholders, has also launched the EAGLE (Eliminate Aviation Gasoline Lead Emissions) initiative, which aims to eliminate leaded aviation fuels by 2030 by promoting the use of unleaded alternatives while ensuring they meet the performance needs of the aviation industry.

Issues with UL94

Despite the environmental and health benefits of UL94, it isn’t without limitations.  It may be an option for lower-compression engines that don’t require higher octane, it has been found to cause engine knocking in higher-compression engines that require a higher octane to operate safely and effectively.  There are no known modifications that can be made to these types of engines that would allow them to run safely and effectively on UL94. In addition to engine knocking, it has also been shown to cause exhaust valve recession. This is due to the lack of lead, which can cause excessive wear on valves and lead to engine wear, efficiency loss, and (in extreme cases) engine failure. The issue recently prompted the University of North Dakota (regarded as one of the top aviation schools in the U.S.) to halt its use of UL 94, citing concerns over engine malfunctions and durability.

These limitations present a major hurdle in the widespread adoption of UL94, especially for industries that rely on high-performance aircraft for operations such as aerial mapping. A drop in replacement would be required to keep these aircraft operational while eliminating leaded fuel use.

Enter G100UL

One promising alternative is G100UL, a fuel developed by General Aviation Modifications, Inc. (GAMI). Unlike UL94, G100UL has been designed as a drop-in replacement for 100LL, meaning it can be used in all piston-engine aircraft without requiring engine modifications. It offers the same high-octane rating as 100LL, allowing high-performance aircraft to maintain optimal operation without the risk of knocking or exhaust valve recession​. The FAA has already approved G100UL for use in all spark-ignition piston aircraft, positioning it as a long-term solution.

Issues with G100UL

For an alternative to become a real solution, it needs to be widely available, which is not the case for G100UL.  The National Air Transport Association (NATA) deems that it is not “commercially available” due to it not having an ASTM International (formerly known as the American Society for Testing and Materials) product specification “Because the FAA does not indemnify any entity in the supply chain for damages caused by fuel-related issues, fuel distributors and FBOs will similarly lack assurances that the unleaded fuel they are selling will not expose them to liability.”

Even if G100UL had the product specification and was commercially available, a bit more than 1,000,000 gallons of G100UL is currently available for sale (as of May 2024).  This would leave 6-7 gallons for each of the 167,000 aircraft currently running on 100LL.

Additionally, some aircraft manufacturers, such as Cirrus, have expressed concerns that using G100UL might void warranties on certain engine types.

Conclusion

The push to ban 100LL is inevitable, driven by undeniable health concerns surrounding lead emissions. However, transitioning to alternatives like UL94 and G100UL presents challenges for aircraft used by aerial mapping firms. High-performance piston-engine aircraft, which compose most of the aerial mapping fleet in the US, face risks of engine failure from using UL94 due to engine knocking and valve recession. While G100UL shows promise as a true drop-in replacement, its limited availability, and potential warranty concerns make the transition a longer-than-ideal process. Rushing to implement and enforce 100LL bans will likely lead to increased insurance premiums and safety risks due to concerns over engine malfunctions. Additionally, higher mobilization costs from rising insurance rates (combined with increased maintenance and fuel expenses) could prolong project delivery times as aircraft face longer maintenance periods and potential fuel shortages.

The aviation industry must balance environmental concerns with operational safety and engine compatibility as it moves toward a future without leaded aviation fuel. Until alternatives are more widely available and proven safe for all piston-engine aircraft, the transition away from 100LL will be gradual but ultimately necessary for the health of both people and the planet.

Sources

• Government records of attempts to ban leaded fuel: The History of the Elimination of Leaded Gasoline
• Aircraft Owners and Pilots Association fighting 100LL bans: AOPA Fights Back on Washington State Bill Banning 100LL Sales
• Concerns over 100LL substitutions: Avgas Developer: Drop-In Fuel for 100LL Is Not Possible
• Santa Clara County Ends Sale of Leaded Aviation Fuel: Sale of Leaded Aviation Fuel Ends at Reid-Hillview Airport
• Health effects study of leaded aviation fuel: Santa Clara County Lead Study
• FAA and Santa Clara County partnership on 100LL transition: County that Banned 100LL Invited to Be Part of FAA Project on Best Practices for Transitioning to Unleaded Fuel
• G100UL as a drop-in replacement for piston aircraft: G100UL Unleaded Fuel
• Issues with switching to UL94 from 100LL: University of North Dakota Drops UL94 Due to Valve Damage
• Exhaust valve recession concerns with UL94: University of North Dakota Stops UL94 Use Following Valve Recession Concerns
• Potential warranty concerns for G100UL in Cirrus aircraft: Cirrus Advises G100UL Use May Void Warranties
• Statistics on piston-engine aircraft in the U.S.: MIT Study on Health Risks from Piston-Engine Aircraft
• FAA’s EAGLE initiative to eliminate lead emissions by 2030: FAA and Industry Chart Path to Eliminate Lead Emissions from General Aviation
• G100UL availability data: More Than 1 Million Gallons of G100UL Unleaded Fuel Now Available
• Commercial availability issues for G100UL: NATA Challenges GAMI’s Assertion of G100UL’s Commercial Availability