Best Drones for Roof Inspections in Singapore

Singapore’s “Green Plan 2030” has accelerated the deployment of solar photovoltaic (PV) systems across HDB rooftops, commercial industrial buildings (JTC), and private landed estates. However, the tropical climate—characterized by high humidity, intense UV radiation, and sudden convective rain—creates a high-stress environment for solar hardware.

Traditional manual inspections involving scaffolding or man-lifts are not only “high-risk” under MOM (Ministry of Manpower) Work-at-Height (WAH) guidelines but are also prone to human error and data gaps. Enter Enterprise-grade Unmanned Aircraft (UA).

1. The Technical “Must-Haves” for Solar Thermography

For a drone to be viable for professional solar inspections, it must satisfy three technical pillars: Radiometric Thermal Sensitivity, High-Resolution RGB Imagery, and Positioning Accuracy.¹

• Radiometric Thermal Sensors: Standard thermal cameras only show temperature gradients. You need a Radiometric sensor (e.g., 640 x 512 px resolution).² This allows you to measure the exact temperature of a specific pixel, identifying “hotspots” that indicate cell failure, bypass diode issues, or delamination.³

• Mechanical Shutter RGB Cameras: To detect physical cracks (micro-cracks), bird droppings (soiling), or glass shattering, a 20MP+ sensor with a mechanical shutter is preferred to eliminate rolling shutter distortion during flight.⁴

• RTK (Real-Time Kinematic) Integration: In the dense urban canyons of Singapore, GPS multipath interference is common. RTK-enabled drones provide centimeter-level positioning, ensuring that every identified defect is tagged with a precise coordinate for maintenance teams to locate on-site.⁵

2. Navigating the Singapore CAAS Regulatory Framework (2025 Update)

Operating a drone for commercial roof inspections in Singapore isn’t just about the hardware; it’s about the legal “Permit-to-Fly.” Under the Civil Aviation Authority of Singapore (CAAS) 2025 guidelines, strict compliance is required for all business-use cases.⁶

Registration and Broadcast Remote ID (B-RID)

As of December 1, 2025, all Unmanned Aircraft weighing above 250g must be equipped with Broadcast Remote ID (B-RID).⁷ This “digital license plate” allows CAAS and security agencies to monitor UA activity in real-time, ensuring airspace safety in our busy flight corridors.⁸

Professional Licensing Requirements

For solar panel inspections (a commercial activity), the operator must possess:

1. UA Pilot Licence (UAPL): Mandatory for any commercial operation or any UA weighing >7kg.⁹

2. UA Operator Permit (UOP): Issued to the business entity, ensuring the company has a robust safety management system and operations manual.

3. Activity Permit (AP): Required for each specific inspection site, especially if the location is within 5km of an aerodrome (e.g., Paya Lebar Airbase or Changi Airport) or within a “No-Fly Zone.”¹⁰

3. Best Drones for Roof Inspections

Choosing the right platform depends on the scale of the roof and the depth of data required. Below are the leading technical specifications for the current market leaders in Singapore.

A. DJI Mavic 3 Thermal (M3T) – The “Compact Workhorse”¹¹

The M3T is currently the industry standard for rapid deployment in Singapore’s residential and mid-sized commercial sectors.

• Thermal Resolution: 640 × 512 @ 30fps.¹²

• Visual Camera: 48MP Wide, 1/2″ CMOS.¹³

• Key Advantage: Its foldable design makes it ideal for urban mobility (easy to carry into HDB lifts or up cat-ladders).¹⁴ It supports the RTK module for high-precision mapping.¹⁵

B. DJI Matrice 350 RTK (M350) – The “Industrial Giant”¹⁶

For large-scale industrial rooftops or floating solar farms (like Tengah Reservoir), the M350 is the gold standard.¹⁷

• Payload Flexibility: Can carry the Zenmuse H30T, which offers superior thermal sensitivity and laser range-finding.¹⁸

• Weather Rating: IP55. Singapore’s unpredictable “Sumatra Squirts” (sudden rain) can ground smaller drones, but the M350’s ingress protection allows for a safer return to home (RTH) in light rain.

C. Autel EVO II Dual 640T V3

A strong contender for those looking for an alternative to the DJI ecosystem.

• No Geofencing: Unlike DJI, Autel does not use “No-Fly Zone” lockouts within its software. While this provides more freedom, it puts a higher responsibility on the pilot to ensure CAAS permits are in order before take-off.

Part 1 Summary Table: Technical Comparison

1. The Technical Workflow: Precision Flight Planning

To ensure that a solar inspection is technically valid for insurance or warranty claims, the flight must be executed with mathematical precision. The most critical metric here is Ground Sample Distance (GSD).

Calculating Ground Sample Distance (GSD)

GSD is the real-world distance between the centers of two consecutive pixels. For solar inspections, a GSD of 1 cm/pixel to 3 cm/pixel is required to detect micro-cracks or specific cell failures.

The formula to calculate GSD for a drone is:

Where:

• $S_w$: Sensor width (mm)

• $H$: Flight height / Altitude (m)

• $F_l$: Real focal length (mm)

• $I_w$: Image width (pixels)

Practical Example: Using a DJI Mavic 3 Thermal (Sensor width 6.4mm, Focal length 4.4mm, Image width 640px) at an altitude of 30 meters:

Note: To achieve the desired 2 cm/pixel resolution, the pilot would need to fly closer (approx. 9 meters) or use a higher-resolution sensor like the Zenmuse H30T.

2. Defect Classification: What the Thermal Data Reveals

Once the flight is complete, the radiometric data must be analyzed. In Singapore’s high-irradiance environment (often exceeding $1000 W/m^2$), anomalies are categorized by their $\Delta T$ (Temperature Difference) compared to a “healthy” reference cell.

3. The Software Ecosystem: Turning Imagery into Insights

Raw images are useless without processing. In Singapore, professional firms typically utilize one of three major platforms:

• DJI Terra: Best for users within the DJI ecosystem. It excels at local, offline processing—ideal for sensitive government or defense sites in Singapore where data sovereignty and “Air-Gapped” processing are required.

• DroneDeploy: A cloud-based leader. Its “Social” features allow a facility manager in Paya Lebar to share a 3D orthomosaic with a contractor in Tuas instantly. Its AI-driven “Solar Inspection” tool automatically tags defects.

• Raptor Maps: The gold standard for utility-scale solar. It provides a “Digital Twin” of the entire solar farm, allowing O&M teams to track the degradation of individual panels over a 20-year lifecycle.

4. ROI Analysis: The Economic Case for Singapore

For Singaporean facility managers, the transition from manual “I-V Curve Tracing” to drone inspections is driven by three financial levers:

A. Labor Cost Reduction

Traditional manual inspections for a 10 MW industrial rooftop can take 10 to 15 days of work-at-height (WAH) labor. A drone can complete the same area in 3 to 5 hours.

• Manual Cost: ~$10,000 (manpower, scaffolding, safety permits).

• Drone Cost: ~$2,500 (pilot fee + processing).

• Savings: ~75%.

B. Yield Optimization

A single bypassed string (1/3 of a panel) may go unnoticed for years during manual checks. Identifying and replacing these faulty components can increase total energy yield by 3% to 5%. In a landscape where electricity tariffs remain volatile, this represents thousands of dollars in recovered revenue annually.

C. Safety & Compliance (BCA TR 78)

The Building and Construction Authority (BCA) of Singapore introduced TR 78, the Technical Reference for using drones in building inspections. Adhering to drone-based workflows significantly lowers a company’s insurance premiums by reducing the “Risk of Fall from Height”—the leading cause of workplace fatalities in Singapore.

Conclusion: The Future is Automated

As we head into 2026, the focus is shifting toward “Drone-in-a-Box” (DIB) solutions, such as the DJI Dock 2. These systems allow for scheduled, autonomous inspections without a pilot needing to be physically present on the roof, providing 24/7 monitoring of Singapore’s green energy infrastructure.