Let us calibrate. Let us eradicate. Let Us Drone.

In a perfect world, we would be able to fly our drones whenever and wherever we felt like it; never getting any errors or malfunctions. But this world isn's perfect, and we have annoying things like jobs that dictate when we can fly, and the FAA to say where we can fly. When Saturday finally does come around and our location is in the green, we get VPS errors *sigh*. All is not bad though, it's still Saturday, and I'm going to tell you how to get rid of those vision system errors on your Phantom 4 Pro.

In this post, we will talk about common reasons for vision system errors on the Phantom 4 Pro (applicable to the other Phantom 4's) and how to calibrate the vision system to eradicate those errors. 

What is the Vision System

DJI has worked very hard to make their drones user-friendly. The remote control helicopters I would fly as a teenager were incredibly difficult to maneuver compared to any of DJI's drone lineup. Why is this? The incorporation of GPS and a Vision Positioning System (VPS) to keep the aircraft extremely steady are certainly two of the reasons.

The Vision System on the Phantom 4 Pro is comprised of two ultrasonic sensors (located on the bottom) and three stereo vision sensors (located on the back, front and bottom).

Ultrasonic sensors emit high-frequency sound waves that bounce off surfaces back to the drone to provide distances of objects.

Stereo vision sensors are cameras that feed images to the drones processor, which is then able to identify the depth of objects by using software that assigns colors to corresponding distances.

This is a basic description of the VPS, and although not part of the VPS, I should note that the Phantom 4 Pro (and P4 Pro V2.0) have infrared sensors on the sides as well. What isn't widely known is that those infrared sensors only work when the drone is in beginner or Tripod mode. Sure, it's still nice to have them, but don't expect the infrared sensors to save your butt if you're rolling towards a wall at 20 MPH.

If you have the original Phantom 4 or Phantom 4 Advanced, you will not have sensors on the back or sides of your drone.

Common reasons for Vision System errors

Ever receive one of the following messages while flying your Phantom 4 Pro?

• “Downward Vision Sensor Calibration Error. Precision Landing May Fail”. Well, that's not good.
• “Vision Sensor Communication Error (10c00)”
• “Vision System Error”
• “Forward Vision Sensor Calibration Error. Precision Landing and Obstacle Avoidance May Fail”
• “Restart Aircraft. Contact DJI Support if the Problem Persists.”
• “Vision System Error (f00400)”
• “Recalibrate Vision System using DJI Assistant 2”
• “Recalibrate the Vision System. Use DJI Assistant on Mac or PC.”

It may be difficult to ascertain why you are getting errors with the VPS, but I have compiled a list of some common instances where people have gotten errors.

Problem: You may get an error or the drones VPS might just not operate correctly when flying over water. This is clearly stated in the manual: “The performance of your Vision System and Infrared Sensing System are affected by the surface being flown over”, and under the types of surfaces listed we see “Flying over water or transparent surfaces”.
Solution: A lot of people have recommended turning off the VPS when flying over water. I usually don't (unless I am flying low), but it is worth a shot if you are getting errors or notice erratic behavior while flying over water. To disable vision positioning, go to settings>visual navigation settings>advanced settings>enable vision positioning. 

Problem: You receive a vision system error after a firmware update. 
Solution: Try calibrating the VPS. If that doesn't work, try refreshing the firmware. You can refresh the firmware with DJI Assistant 2 or within the DJI GO 4 App.

Problem: You receive a vision system error with your brand new drone. 
Solution: Calibrate the VPS. We all know how much of bumpy ride packages go through in the mail, and your P4 Pro doesn't love all that jarring action.

Problem: VPS error after a crash.
Solution: Well, we can't be too surprised if we get a VPS error, along with a few other errors if you crash the drone. Not only should you calibrate the VPS after a crash, but it would also be wise to calibrate the IMU and compass. Do a thorough inspection of the drone to make sure everything is structurally sound as well!

Problem: VPS error after a DJI GO 4 App update. 
Solution: Forceclose the app and see if the error is still present upon reopening it. If it's still there, delete the app and download it again. If none of this works, consider rolling back the app to the previous version. I can’t speak much to this as I have never tried it, but here are YouTube tutorials on how to undertake such a task: click here for Apple, and here for Android.

Problem: VPS error after installing the HDMI output module.
Solution: After installing the HDMI module it is very important to refresh the firmware, even your AC and RC are currently on the latest firmware update.

Problem: VPS error after the drone came into contact with moisture. A guy reported that after landing in the snow he got a VPS error, but the drone wouldn't calibrate with DJI Assistant 2. Turns out moisture had fogged up one of the downward stereo vision sensors.
Solution: After letting it dry out for a couple of days he was able to calibrate the VPS with no problem.

Problem: You may have a bad VPS module. 
Solution: If you've tried everything and are still getting vision system errors, there is a chance that the VPS module is bad. DJI offers a 6-month limited warranty for the VPS on the Phantom 4 Pro. In my article Is My DJI Drone or Gimbal Under Warranty? Check Here I explain how to go about initiating a return.

How to calibrate the Vision System on the P4 Pro 

Calibrating the vision system is a relatively simple process, and it takes about five minutes. You will need DJI Assistant 2 for the calibration.

1. Make sure that you are on the latest firmware update.
2. If you haven't already, download DJI Assistant 2 from DJI's website here.
3. Set the resolution of your computer screen to 1600×900.
4. Ensure that you have at least a 50% charge in your battery.
5. Connect your Phantom 4 Pro to a computer with a USB cable.
6. Power on the drone.
7. Launch DJI Assistant 2.
8. Click on Phantom 4 Pro.
9. Click on “Calibration” which you should see on the lefthand menu.
10. Follow the tutorial that will walk you through the steps of calibrating. Note: when I was calibrating the downward sensors, the gimbal make a funny sound, like it was screaming at me. After researching this, others have heard the same sound and claimed that it was “normal”. 
11. After you have tilted your drone in every which way, DJI assistant 2 will begin the calibration, which takes about a minute.
12. Upon completion of the calibration process, DJI Assistant 2 will ask you to restart the drone.
13. Ta-da! You did it, and hopefully, all VPS errors will be gone when you open DJI GO 4.

If you'd prefer, here is a YouTube tutorial video that walks you through each step.

It's very important to set the screen resolution

In order for the calibration to work, your computers screen resolution should be set to 1600 x 900. I have an older 27″ iMac which has a default screen resolution of 2560 x 1440, and I could not calibrate the VPS. I kept getting a “Frame Alignment Error”, and when I clicked on “calibrate” I was met with a white screen.  I kept thinking “where are those darn dots that I see in the tutorial video”. Well, after conducting some research I learned that the resolution needs to be set to 1600 x 900. When I changed the screen resolution under the display settings, the calibration worked flawlessly.

If you have an Apple computer, go to settings>displays>scaled>click 1600 x 900. If you have a PC, the steps may be a bit different, but there should still be a “displays” section under settings where you can adjust the resolution.

Trevor's take

I'll admit it, I can be lazy. I flew for months with a message on the DJI GO 4 App that read “Recalibrate the Vision System. Use DJI Assistant on Mac or PC.” When I went to calibrate the VPS on my iMac, I ran into the issue I mentioned above where the screen resolution was too large. I didn't know that the screen resolution size was the culprit at the time, and I was too lazy to figure out why because, after all, my drone seemed to be flying just fine. When I realized how simple the remedy was, I frowned at myself for dragging my feet.

If you're reading this and currently have a VPS error message displaying on your app, I hope that this post provided some value for ya. What's your experience with the vision positioning system? Have you experienced other errors or problems that weren't mentioned above? Comment below!