Why Cellular? Reasons for Integrating Cellular C2 in your Drone

Cellular connections with drones is a new way for drones to communicate with your ground station or controller that can either bolster the safety of your current set up or replace the traditional telemetry link used by most non DJI commercial drones built today. A few points to consider if it is worth it to integrate or replace fully your traditional connection devices for that of a cellular connection are:

• Allows for Easier BVLOS

• Can be more Reliable than LOS connection

• Not locked into one network

When considering your operations, if BVLOS is on the table then having a cellular connection can help boost your connection reliability and make operations in more sparsely populated areas easier. It also allows the use for multiple countries or network providers by just piggy backing off of the already existing cellular infrastructure that is there by simply removing a SIM card and swapping it for another. Easy swapping allows for moving from country to country or simply keeping the SIM for moving across your own country. When considering cellular having multiple options for connections regardless of where you are, if you have a cell phone connection then you can have a C2 connection.

Another way that cellular is useful is through long inspection routes where there is already existing infrastructure such as roads, railroads, power lines, etc. Here, there are already existing cellular connections in place and even in the more “remote” areas having a drone up to even 100ft can double your connection strength at times depending on physical obstacles or distance barriers. 

The next way you can look at using cellular is to just make your current operations more reliable than they already are. With cellular connections you can give yourself a good connection constantly with good data rates along with it. Or, if you want something with quicker latency that does not go through the internet you can use cellular as a backup that will always be available to you should you lose primary C2. The benefits of devices like the XRD2 is that the footprint of these devices are so small and easy to mount that the weight and power loss is borderline negligible. It also helps that the antennas can be, well, whatever the user wants, from hard plastic paddles to sticky antennas that just stick onto any smooth surface of the drone (or arm of it if you want). 

How to Set Up an Xbox Controller for a Pixhawk Autopilot And Fly Using Botlink's XRD2

The purpose of this guide is to share how to set up using an Xbox controller with a Pixhawk controlled drone to the extent that it is nearly similar to using a DJI drone in practice. There is already a guide on ardupilot here, for easy setup if you already have the joystick they used in that tutorial and you don’t care for mimicking DJI drones. But here we will be focusing on if you do not have the usual joystick and are using a gamepad as well as some safety precautions as well when setting something like this up. Setting up the controller, overall, is easy to do and is intuitive if you are familiar with the Mission Planner software that needs to be used.

Let's start by starting up the drone itself by using a wired connection, if you are using a wireless connection make sure the propellers are OFF the drone prior to messing with controller settings. After connecting the drone you should use whatever connection you will be using to connect the controller to the laptop/ground control station that you’ll be using (I used a wired USB to USB-C). If you wanted to control it using Botlink’s XRD2 then all you would need to do is swap your connection type in Mission Planner to TCP at 57600 for the baud rate. When connecting after that the IP should be default to what Mission Planner asks and you’re connected! After this we go to Mission Planner and select the Actions menu just below the Primary Flight Display and then at the bottom of that menu select Joystick (Figure 1).

Figure 1

After selecting this menu a submenu within Mission Planner should pop up and give you a giant list of control inputs (Figure 2). Don’t get too concerned with all the info as realistically you should only need Channels 1-4 on the left and at minimum 3 buttons on the right to make sure everything is in order. One thing to keep in mind, the Enable button at the top should say that the whole time, if it ever says Disable then that means the drone is reading your inputs. But as we go through the flow for setting up channels is easy as:

• Select the Auto Detect button for Channel 1 on the left half of the menu

• Move the Pitch joystick to have it read it.

• Continue this same process for Channels 2, 3, and 4 for Bank, Throttle, and Yaw respectively.

• Keep in mind that the drop downs to the left can read different depending on the controller being used, don’t change them to what I have. The same goes for the Reverse checkmark for Pitch. Test fly it before checking that.

• REVERSE THROTTLE USING THE CHECKMARK TO THE RIGHT OF THE CHANNEL.

Figure 2

After we get the channels for controlling the drone we will want to map buttons onto the drone, since this is for keeping a quadcopter as close to a DJI drone as possible we will use 4 buttons mapped as Arm, Disarm, RTL, and PosHold. This will allow us to obviously arm and disarm the drone but also let go of the sticks and the drone will keep its position in space without us needing to do anything else. For setting up buttons we go with this process (Figure 3 for reference):

• Select Detect next to the button you want to use for Arm 

• Press the button on the controller you want to use for this button (I used LB and RB for Arm/Disarm respectively).

• On the right, select the drop down and then find Arm.

• Repeat for Disarm (order does not matter, this could be button 16 and 7 on the list and it would work all the same).

• Do the same for PosHold, but on the drop down select ChangeMode and then select the Settings button.

• This will open a new window with a drop down, there is no “save” button, it will remember what you put in the drop down after closing the window.

• Repeat for RTL.

Figure 3

Prior to exiting out of the Joystick window we need to hit Save at the top of the screen and then hit Enable (Note: MAKE SURE THE DRONE DOES NOT HAVE PROPELLERS ON PRIOR TO PRESSING ENABLE). Now we will go and see if the mapping was correct. Next we go to the top of Mission Planner and select the Set Up Tab and then go to the Mandatory Hardware drop down. Once here we select Radio Calibration and check to see if Pitch, Bank, Throttle and Yaw are all moving how we want. If your indicators in Figure 4 are not moving make sure the drone is powered with a battery, make sure your controller is connected correctly to the GCS, and go back to the Joystick menu and verify that the same settings are there and that at the top it reads Disable and not Enable. 

Figure 4

The last check we need to do is that Arm and Disarm work as intended as well as any mode swapping we decided to map onto the controller. The easiest way to check if the drone responds to mode changing is to check the bottom left of the Primary Flight Display (Figure 5) and check what mode it is currently in and then change it using the controller buttons you mapped. If it changes then there you go, that is working as intended. For checking if Arm and Disarm work I used this process:

Figure 5

MAKE SURE NO PROPELLERS ARE ON THE DRONE PRIOR TO DOING THESE STEPS.

• If your drone has a controller/Transmitter you already use with a hard “Motor Cut off” switch, then enable it. If not and it has a safety switch on the drone, don’t switch it on.

• Once one, or both, of those safety features are enabled go ahead and try to Arm. 

• The drone arming buzzer should sound and it should try to arm but will be denied and then Mission Planner will give you the reason why.

• To check if disarm works as intended, Arm and then immediately Disarm.

• The drone should sound the buzzer and then stop immediately prior to getting the prearm checks and figuring out it can’t arm. 

Now the last thing that needs to be done is a quick test flight. All my test flying was done using Botlink’s XRD2 with an LTE connection, you can use your drone’s telemetry radio that comes with it as well. Some quick pointers for test flying this and for future use are as follows:

• Always keep the drone in PosHold during the first flight to verify controls are working as intended

• Reverse channels as needed (I needed to with my Pitch channel)

• Every controller/joystick is different

• You will need to select Enable in the Joystick submenu every time you start up the drone.

• If you disconnect the controller during flight it has a hard time figuring out you reconnected, just hit Disable/Enable on the Joystick menu until it starts responding again.

• Make sure you have a failsafe for what the drone will do incase your controller disconnects (RTL/Loiter/etc.)

Tips on how to get DJI GO 4 Ready for Survey Flights

When initially configuring a DJI drone to fly there are some easy rules of thumb to follow with the settings and controls given to the pilot. When trying to configure the drone for a survey flight there are a multitude of settings and icons to look out for when setting up the drone. Then there are the others that don’t “pop” out quite as easily to all pilots but are nonetheless important to know and understand. In order, a pilot should look out for these 4 general tips when first using a DJI drone for survey flights: 

1. System Status

2. Status Bar Icons

3. General Settings

4. Camera Settings

System Status

When opening up the DJI app and going into the camera view of your drone, this will allow you to more easily change and edit any settings that you may want to in regards to conducting a survey flight. The first thing that you will encounter when going into the camera view is the top left corner showing the System Status. Usually this needs a bit to give you the thumbs up to fly as it searches for a GPS signal, but it should be ready to go most of the time prior to flight. When it isn’t ready to go, just clicking the text will pull up the system status menu which will display All the statuses that need to be addressed prior to take off. These settings can include simple configuration settings (like max flight altitude or distance) to needing to do manual calibrations like compass calibrations.

One thing to note with the System Status is that the aircraft can take off with select software or calibrations not done. This, very obviously is not good as sometimes aircharts update or maybe your compass calibration is off by over 20 degrees! It is always important to update prior to leaving to the field to fly as then you aren’t surprised by updates or go out and calibrate your drone to the area you are in prior to the day you need to fly to ensure it is correctly calibrated for that area.

Status Bar

The Status Bar on the top of the camera view gives you an idea of the health and the most general settings that you have on your drone. From left to right these status symbols are read as: 

• Flight mode: Be sure to have this out of Beginner Mode as this will limit the range of motion and speed of your aircraft!

• GPS Signal Strength: This is what it says, the strength of the GPS signal.

• Visual Navigation Settings: These settings show the bars on the camera view for when you are nearing an obstacle, not necessary for survey flights, but if using the app regularly then having at least forward and backward signals is recommended.

• Controller and Video Signal Strength: These two icons display the strength to the controller and how much quality streaming you have. Selecting either of these status bars will pull up their respective settings for binding in the controllers case to change the quality of video in the video’s case.

• Battery Life: If using Botlink’s Capture app this will be directly displayed as well on that app, it is important to note the battery life prior to launch to be sure if you will have to conduct a battery swap mid survey or not.

• General Settings: All of the settings we just went through plus some extra.

General Settings:

When going through the General Settings, the best rule of thumb is to go through all of them when you first get a DJI and find out what is or is not necessary with what your operations look like. An example would be recording audio with Video Cache, is it necessary for survey flights? No, but would you maybe want to use it for other commercial flights or other events? Maybe, so always make sure you are aware of your settings prior to launching the aircraft as adding something like sound to your videos can fill up your SD card quicker depending on the size of it.

Camera Settings

The last setting that you may want to mess with is the Camera Settings. These settings are usually good as is and the software that DJI provides will auto adjust the settings to give you better photos. But in the event that it doesn’t adjust correctly, in the camera settings menu to the left of the screen allows you to change between video/photos, adjust focus, aperture, and shutter speed. As well if you are interested in photo formats that aren’t .jpeg or the default image size there are settings to adjust that under the photo settings.

All of these settings together should be able to get you to the point where all you have to do is start up DJI GO 4, wait just 10 seconds for all the signals to update, then swapping over to Botlink’s Capture app to start planning and executing your survey flight with ease.

Best Practices for Survey Drone Flights for 3D Mapping

With conducting survey flights with the need of the end product being a 3D map there are a handful of things to consider when going about these operations. These items to consider, and will be discussed here, are as follows:

• Type of Survey

• Platform

• Weather

• Flight Settings

• Post Analysis

Survey Type

When deciding whether or not to do a survey map for a given area it is important to decide what type. For instance a quick survey of the land to find out of any damages, say for a farm after flooding, will only require the shortest of flights and nothing fancy on the camera work to be able to determine the information needed. Once you start needing volumes for soil pile, aggregate, or general lay of the land that isn’t flat you will need a survey conducted that gives more information to pull from.

Choosing a Drone

Picking a drone to use is the first step in the process for conducting 3D drone surveys and the best thing to know is you are looking for flight time/distance, usability, and camera/sensor quality. The flight time and distance per minute is more important than the flat battery life as fixed wing aircraft can fly equal time as a quadcopter, but cover more than 10x the area that the quadcopter at times. So deciding what platform to use is important as well as keeping in mind that most fixed wing platforms can take a bit more to use and understand than an off the shelf DJI quadcopter. Usability is important in where you are operating, there isn’t a need for a fixed wing aircraft when you plan to do multiple, small sections of land/area, and likewise there is a greater need for a fixed wing when you have possibly hundreds of acres of land to survey. And last is to make sure the sensor or camera being used is high enough quality that you don’t have to skirt tree lines in order to take good quality photos.

Weather Conditions

The next step is verifying when good weather is available. This will vary wildly depending on the platform and the drone being used in that platform. For instance, a regular Phantom 4 from DJI can take winds up to about 15 - 20 knots depending on pilot confidence and responsiveness, but other, larger, quadcopters can be rated as high as 35 knots! In the same vein when using a fixed wing drone the airspeed tolerance can be just as variable depending on size and powerplant being used. When using both platforms the best wind conditions will be steady winds with low gusts (1-3 knot difference with gusts) to avoid the aircraft from being thrown around or off course randomly and to save power so servos or propellers don’t have to work harder to stay straight and level. The other consideration that one should have for weather is cloud cover, the best time to fly is with no clouds or overcast skies. When flying with scattered clouds you can sometimes get “ghosting” in the stitching process that makes it harder for one to read the data given so, while it might not be a situation to ground or stop operations it is something worthwhile to consider.

Choosing Flight Settings

Flight settings are the most important to your flight as it will determine whether or not you will need to stop and put a new battery in or not as well as determine how much information you will be gathering from the flight. If you need a simple survey flight, doing a simple vertical or horizontal flight with just 85% overlap on the photos will be more than enough to conduct the survey. Grid surveys, going both vertically and horizontally over the area of interest, will offer better 3D object stitching, but typically won’t increase accuracy for a simple survey by a noticeable amount and will just increase flight times. 

Height is the next option for flight settings, but it depends on the camera more than the platform being used. If you want more information with better quality, the best thing to do is start at 200ft then lowering the height of the mission by 10-15 foot increments. Lowering the height will give you more photos to work with as well as them being better quality. To start, depending on the area of use, somewhere between 200ft and 175ft is the best starting point and then decrease from there.

Flight Options for 3D Objects

If you want to make a full 3D object and your object is more than a pile of rock or landscape, then doing both vertical and horizontal passes with camera tilt will be the best option. If it's just one single building or structure then circular patterns can work, but for that to be effective you must do multiple flights at different altitudes and different camera angles. This part is more up to pilot discretion and all of these methods can give you a clear 3D image to varying degrees, just depending on the situation. It also is not a horrible idea to go out to the area you wish to survey and do multiple surveys and save them individually to see how well they pan out, usually you can do one survey per battery so this can be worth your time and save you money down the road easily! Just be cautious of which type you are planning to do, if you’re looking to survey a pile of dirt, the settings talked about previously of 200ft and 85% overlap will be easier and quicker than doing 5-10 circular flights to give you the same information.

Post Analysis

Post analysis will be uploading the images to a stitching software and then going over it yourself either through visually seeing what you needed to or using tools to find volumes, heights, or damages in the image set provided. If going for a 3D map then this part will be most important as most stitching software, after stitching and forming your 3D object, will be finicky about placements for measurements, but the degree for error is still enough that not having perfect placement won’t even take you mildly off accurate calculations.

Again, when using Botlink’s Capture App and then Insites the recommended settings for the most efficient use of time and best picture for the lowest flight time:

• Height - 200ft

• Overlap - 85%

• Gimbal Angle - 90 degrees

• No Grid Pattern
  

Botlink and Innovets Fly Ground Breaking Flight

Botlink and Innovets Fly Ground Breaking Flight

After nearly a year of coordination and development, Botlink and Innovets Aerospace flew over a Department of Defense (DOD) facility using a Commercial-Off-the-Shelf (COTS)Unmanned Aerial System (UAS) to collect imagery

Grand Forks, ND, June 8, 2020: Botlink and Innovets Aerospace are proud to announce a joint collaboration in which they were the first group to receive a waiver to fly a COTS UAS within DOD airspace since DOD instituted a ban on small COTS Unmanned Aircraft in 2018.

Operating from Grand Sky UAS Business and Aviation Park, Innovets and Botlink operated two UASs to collect updated aerial imagery of the park.  This is the first small UAS commercial flight in over two years and the first to operate under a waiver for the ban on COTS UASs within USAF airspace.

The waiver process was conducted in close concert with local Air Force leadership. “This is a team effort. DoD has security concerns regarding the small COTS UAS market, and our goal is to work with our military partners to promote safe and secure operations through the combination of operational protocols and innovative U.S. technology manufacturers” stated Mike Whitted, CEO of InnoVets Aerospace.

Both of the UASs were designed, built and tested by the Botlink team in Fargo.  “Botlink has a long history of taking on the biggest challenges, and creating world-class technology in the UAS market,” said Terri Zimmerman, Botlink CEO, “This is another example of how Botlink is laying the foundation for the future growth of the entire industry.”

About InnoVets Aerospace – InnoVets is a 100% Veteran owned and operated aerospace advisory and services business.  They specialize in commercial/DOD advisory liaison and Unmanned Aerial Systems (UAS) services, including operational procedures development, aviation safety, training, flight planning and scheduling.  For more information visit:  http://innovets.net/

About Botlink - Botlink was founded in Fargo, N.D. with military pilots and engineers with the intent to safely share the benefits of UAS. Botlink is a UAS software and hardware development company, that leads the market in LTE communication technology. Botlink also provides automated UAS control and safety features allowing operators to remain safe and compliant with complex flight regulations. For more information visit: https://botlink.com/

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