Announcing Two New Sensors for the DJI M300 RTK
Is the DJI M300 RTK now the best drone for land surveying?
With the announcement of these two new sensors, the answer might be yes. This article breaks down the best land surveying and mapping sensors for the DJI M300 RTK.
DJI just announced two new payloads for the Matrice 300 RTK:
Zenmuse P1 - shipping March 2021
Zenmuse L1 - shipping January 2021
DJI designed both payloads for surveying and mapping. This announcement is good news for land surveyors because, until now, the payloads for the M300 were fantastic for inspection but not very good for photogrammetry and the production of topographic and planimetric surveys.
Most people purchase the M300 with the H20T sensor. It is a multi-sensor payload, which is fancy and offers flexibility. But, the actual sensor that we would use for photogrammetry is not as good as the built-in 1-inch 20MP CMOS sensor with a mechanical shutter that the Phantom 4 RTK has. So, you would get better accuracy from the Phantom 4 RTK than you would from the M300 with the H20T – Quad-Sensor Solution. That is because both cameras are subpar for photogrammetry, the wide camera is only 12 MP, and the zoom is not very good for photogrammetric processing. Fortunately, the Zenmuse P1 appears to be a phenomenal sensor for photogrammetry workflows, which has us very excited.
Here’s what we know so far. Per DJI, we expect the Zenmuse P1 to start shipping in March 2021 and the Zenmuse L1 sometime in January 2021. Because of our distributor agreement we cannot share the official pricing in this article. Please let us know if you would like a quote for the DJI Matrice 300 RTK and these sensors.
Aerotas will support and sell both sensors once they become available. And, Aerotas will process the data for both photogrammetry and LiDAR.
Zenmuse P1 - Photogrammetry
The Zenmuse P1 has a 45 MP sensor and a global mechanical shutter. These specs are excellent for photogrammetry. By comparison, the Phantom 4 RTK has a 20 MP sensor, and that data is of very high quality. With a 45 MP sensor, you will be able to fly higher, save time collecting data in the field, and still get 0.1’ vertical accuracy.
There is little question about whether or not the M300 RTK with the P1 package will be good or not - it will be a great drone! But, it will also be a very expensive drone. The main question is - will the improved performance be worth the significantly increased price for most surveyors? The answer probably depends on the type of projects you are doing and your budget.
Full-frame Camera
45 MP Sensor
Global Mechanical Shutter
3-axis Stabilized Gimbal
The Zenmuse P1 is offered with these lens options.
Multiple Fixed-focus Lens Options
DJI DL 24mm F2.8 LS ASPH (with lens hood and balancing ring/filter), FOV 84°
DJI DL 35mm F2.8 LS ASPH (with lens hood and balancing ring/filter), FOV 63.5°
DJI DL 50mm F2.8 LS ASPH (with lens hood and balancing ring/filter), FOV 46.8°
The P1 will include the 24mm stock, with the 35mm and 50mm sold separately. Please contact us for pricing.
DJI claims that you can “generate orthomosaics without GCPs using the P1.” Aerotas firmly believes that no control is not good enough for survey work. You absolutely need ground control to localize your project and have some ability to detect errors and account for rotation.
When appropriately deployed, the DJI RTK system can calculate image geolocation with high precision but low accuracy. Aerotas has developed a workflow that enables surveyors to lock the relative accuracies in photogrammetry processing and shift the entire project to match the GCPs that the surveyor shot using a more accurate instrument. This workflow ensures full-site accuracy without the need for manual PPK processing or ground control distributed throughout the entire site.
Zenmuse L1 - LiDAR
We are very excited about this LiDAR + RGB solution for aerial surveying. The Zenmuse L1 integrates a Livox LiDAR module, a high-accuracy IMU, and a camera with a 1-inch CMOS on a 3-axis stabilized gimbal. When used with Matrice 300 RTK, the L1 efficiently captures the details of complex structures and promises to deliver highly accurate models.
Livox Lidar Module
RGB Camera (similar specs to the camera on the P4RTK)
20MP
1-inch CMOS
Mechanical Shutter
High-accuracy IMU
In the past, a good LiDAR setup would cost North of $170,000. But, the price for this LiDAR solution is very competitive. Please contact us for pricing.
The L1 is a more complicated product. The LiDAR module, by itself, will definitely have lower accuracy than even the Phantom 4 RTK. Even DJI’s typically optimistic accuracy recommendations (~0.2’ vertical and ~0.3’ horizontal at 150’ AGL altitude) are worse than what the Phantom 4 RTK can produce with photogrammetry.
So in non-vegetated areas. The P1 will be superior to the L1. However, it is in areas with light to moderate vegetation where the L1 can shine. The likely best workflow will be to use a combination of photogrammetry and LiDAR data to get the best of both worlds, which can be done because the L1 has a 20MP global shutter camera in addition to the LiDAR. A project will have to have both photogrammetry and LiDAR processed, and then as part of the data processing step, the highest quality data from each sensor will be merged into a final product.
Thankfully, Aerotas has already worked on these complex workflows and will be able to get the highest quality results from day one with the L1. But make no mistake, the L1 is NOT for everyone, and it is not universally better. It is only better when there is vegetation to deal with. If your primary focus is on moving dirt, or if you operate in desert environments, then the L1 is most certainly NOT for you.
Open Questions
While we are optimistic about these platforms, Aerotas will wait to test the entire system before providing concrete recommendations. We are confident the answers to these questions will be satisfactory, but they will need to be addressed and tested in real-world conditions first.
What is the real-world accuracy of these payloads?
LiDAR, in particular, is subject to a lot of sources of noise in the real world. We are skeptical of the DJI marketing numbers.
What is the actual price / ROI on these? Will they make business sense?
How complicated is the workflow? Since it’s a first-party payload, it’s likely very good, but Aerotas needs to test.
Can the data be easily integrated into 3rd party software for processing, or will DJI attempt to “black-box” the whole thing, restricting analysis abilities? I.e. will you be locked into using DJI Terra?
Comparison & Rough Pricing
All In Price
Camera
LiDAR
Accuracy
Complexity
Good For
Phantom 4 RTK
~$12,000 $
20MP Global Shutter
n/a
0.1’
Medium
Most projects
M300 RTK + P1
~$35,000 $$$
45MP Global Shutter
n/a
0.1’
Medium
Large projects, high detail requirements, challenging flight conditions
M300 RTK + L1
~$45,000 $$$$
20MP Global Shutter
Yes
0.3’
High
Vegetated project sites
In short this is an exciting announcement. The M300 RTK + P1 sensor could very well become our most recommended system for drone surveying and the creation of topographic and planimetric surveys. And, the L1 might finally put drone-based LiDAR within reach. But, there are still many unanswered questions. As soon as we get a hold of the hardware we will update you with our findings and recommendations.