How to to get maximum aircraft speed

Shorter answer to maximize aircraft speed: 

• Fly in bright light conditions (hard during winter)
• Open your aperture up all the way if you can
• Step up the ISO (I wouldn't exceed 800) 
• Fly higher
• Use less along track overlap (but you usually have to make up for it with more across track overlap so it is a wash)
• Use the fastest SD card you can find and change the SD card write speed in the settings to 2 seconds/image (will only work reliably on certain cameras)

OK. I just did the experiment again. I am using a DJI Air 2S, the f stop is not adjustable, but the ISO is. I flew in mid afternoon when the sun was still pretty high. I have done the intervalometer test and got 60 photos in 120 s, so I set the photo interval to 2 s. I have "Slow Aircraft According to Light Conditions" OFF. Return speed is set to 10 m/s.

I created a new mission with a height of 60 m. I set the ISO to 3200 (I wouldn't want to fly a real mission at that ISO, but this is an experiment). I set the ISO while the drone was in the ascent phase, so all photos were taken at 1/2000 s, ISO 3200, f/2.8 (this is from the exif data).

My camera is 5472 x 3648 pixels with a field of view of 78.6°, so I calculate a GSD of 1.38 cm at 60 m (you might calculate a slightly different value). If I wanted a smear of 2 x GSD (I would actually want it quite a bit smaller), then the maximum drone speed should be 2.78 cm in 1/2000 s or 55 m/s.

If the Frame Rate is the limiting issue, then I can take one photo every 2 s. My photo footprint, is, I think, 51 x 76 m. I have an along-route overlap of 83%. So the drone shouldn't move more than 17% of 51 m in 2 s, or a maximum speed of 4.335 m/s.

Both these numbers, 55 m/s and 4.3 m/s are higher than the actual flight speed of 2 m/s.

My question remains: is there a way to get the drone to fly at a speed closer to the maximum allowed by smear and Imaging Frame Rate?

If the slowing for light conditions is turned off the speed does not get adjusted and has NOTHING to do with your exposure times or camera settings. 

But... your most recent flight is showing that it is still getting adjusted. You can see this in the "App_Warning" column in the CSV log files.

Also, in another log file I see that you are collecting RAW images. That will REALLY slow you down since the camera than takes 5 seconds to write each image. 

So first things first: make sure RAW data collection is actually turned off as well as the light conditions slowing. 

What was showing in the exposure time numbers in the video panel while flying? Roughly 1/2000?

What do you have your "Ground Smear Limit" set to in the Settings? Might you have changed that to a value other than 2X?

Sadly, we don't record the raw exposure time but the value we get is what is shown in the video panel exposure text. The log file does have the ground smear value and the speed in it so the those numbers all jive with an exposure time of 1/2000. 

It feels like we are talking past each other, but let me try to address each of your comments (some of which are definitely making me think).

your most recent flight is showing that it is still getting adjusted. You can see this in the "App_Warning" column in the CSV log files.

I am pretty sure that the adjustment (at 15:59:27.476) is Map Pilot Pro slowing the drone down to 2.1 m/s, and is not an adjustment for smear. I definitely had "Slow Aircraft According to Light Conditions" OFF.

Also, in another log file I see that you are collecting RAW images. That will REALLY slow you down since the camera than takes 5 seconds to write each image. 

You are completely right. I did exactly the test that help documents suggested using the intervalometer in the Go Fly app, and it indicated that the drone had no problem writing 60 images in 120 seconds, with raw on. Obviously, I did something wrong with this test, and I'll do the test again, and I'll also turn raw OFF because it clearly leads to image intervals that are too long.

What was showing in the exposure time numbers in the video panel while flying?

"1/200…", which I assume means 1/2000 s. As I said, I got the exposure times from the exif data in the photos.

What do you have your "Ground Smear Limit" set to in the Settings?

As I said, "Slow Aircraft According to Light Conditions" was OFF. If I turn it on, then the limit is set to 0.5 x GSD. While the flight was running, Motion Blur was 0.1 cm, reported by MPP, so that should not have been a problem.

But, still, the question I am trying to answer is: if I get all the pieces together to allow higher flight speeds (high shutter speed to avoid smear, JPEG file format to get photo interval under 2 s, lower front/back overlap between photos), will MPP fly faster, or is the speed shown in the mission plan the absolute maximum that I can get? I am hoping that if I make some tradeoffs (JPEG, not RAW; higher ISO; lower front/back overlap) I should be able to fly at 4 or 5 m/s at an altitude of 60 m, but it seems that MPP will not allow this. Can you confirm this or not? If true, do you think this constraint will change in the future?

I now see that with 83% along track overlap and the Air 2S selected in the Settings with the RAW enabled it will slow down to 2.1 m/s. The DJI docs state that they need 5 seconds to write out the much larger RAW files. Your test may or may not have actually written the files that fast but we aren't going to have it go faster than what DJI says to do to ensure reliable operation. 

With the information in the exposure text string I was trying to see if there was some discrepancy in how the speed was being calculated but it sounds like that wasn't it. The currently reported exposure settings are displayed at the top of the video preview panel. 

Turning the GSD limit to .5X GSD will slow the aircraft down, not speed it up. 

In your quest for a faster speed the exposure time does not come into play at all if the light conditions slowing is turned off. Assuming flight at 60m and just using JPG instead of RAW will get you up to 5.3 m/s from 2.1 m/s. Going down to 80% from 83% will get you up to 6.2 m/s. 75% will get you up to 7.8 m/s. You would probably get more bang for your buck by changing the altitude at the cost of GSD. Flight at 97 meters with 83% overlap will allow you to fly at 10 m/s.

Keep in mind, the fastest you are going to be able to fly is 10 m/s since you are on an aircraft that does not support waypoint flight (15 m/s max). The Virtual Stick controls your aircraft uses are kind of hokey but are what DJI has provided. 

I'll give that advice a try. We expect 5 days of rain, so I can't do anything for a while...

Thanks

Again, I apologize for how long this conversation has gotten, but I want to follow up with a few more (I hope, final) comments.

1. I redid the camera speed test with the DJI Intervalometer function. I found that for my DJI Air 2S, I can take 60 photos in 120 seconds whether the setting is JPEG or JPEG+RAW. I have a "SanDisk 128GB Extreme microSDXC UHS-I Memory Card - Up to 160MB/s" in my drone. This is why I was hoping to use RAW+JPEG setting in MapPilotPro.
2. Zane mentions that DJI specs (?) suggest a minimum photo interval of 5 seconds when shooting RAW + JPEG, and it is clear that when I use RAW + JPEG in MPP, I get photos separated by about 5 seconds. I wonder if this is because of limitations of the camera write speed (which it doesn't seem to be), or if it is because MPP follows outdated or inappropriate limitations suggested by DJI. It might be worthwhile for Zane to look into whether he can use shorter intervals.
3. Zane is right, when I change the setting to take photos just in JPEG, my flight speed in MPP for a particular mission plan (60 m altitude) goes from 2.1 to 5+ m/s, which is exactly the answer I was seeking. I suggest that the documentation for MPP be reviewed, because, even though I think I read everything relevant, the impact of shooting in raw on flight speed was not clear to me. I thought shutter speed and "smear" was the only issue in setting flight speed, but clearly a 5 s interval between photos will limit flight speed, and I didn't fully grok this fact.
4. There is a setting in MPP for photo interval, which defaults to 2.5 s, but can be set as low as 2 s. However, it appears that if you are taking photos in raw, this setting is changed to 5 s, but displays as 2 s. The display in the program should reflect the actual photo interval being used.

1. Are all of the RAW files actually there and valid? We are only doing what the specs say... 

2. The SDK docs actually say it only supports an image every 10 seconds: https://developer.dji.com/api-reference/ios-api/Components/Missions/DJIWaypoint.html#djiwaypoint_shootphototimeinterval_inline

3. We don't generally recommend shooting RAW. Ever. We figured when it flew slowly people would figure that out... Also: https://support.dronesmadeeasy.com/hc/en-us/articles/211429203-RAW-Image-Collection

4. Correct. RAW is a weird case that gets handled as a special case since it weird. 

We don't think it is going to work in most cases but we have added a RAW mode specific SD card write speed setting in version 5.4.15. The default is one image per 5 seconds so we don't get a whole bunch of people having issues right away but you are free to step it up if you think your card/camera can keep up. 

Thank you, Zane. Can’t wait to try it.