# Compass Calibration

Compass Calibration is very important; otherwise the flight control system will not work properly. The compass is very sensitive to electromagnetic interference, which can cause abnormal compass data leading to poor flight performance or even flight failure. Regular calibration is required for optimum performance.

When to Recalibrate: - After any firmware/software update - After a crash (minor or major) - Flying in different location to last flight (far away) - When drifting occurs in flight, i.e. Phantom does not fly in straight lines. - When hovering, Phantom wants to fly in a circular pattern (To ilet bowl effect-TBE) - When compass data is abnormal, the rear LED flight indicator will blink Red and Yellow (See “Led Status” section). - Something magnetic (screw driver with magnetic tip, speaker, magnet ...) got close to your compass/aircraft. - Mechanical structure of the Phantom has changed, i.e. changed mounting position of the compass. - If compass calibration is needed before flight, a prom pt will appear on the DJI Vision app’s camera page.

Need to Know: You do not have to calibrate your compass before every flight (meaning: don’t become compass calibration crazy); this is not necessary and may actually increase your chance of having a problem. You don't want to risk introducing any issues that weren't there before by re calibrating too often. DJI reco mmend recalibrating only when moving far away from last flight point.

- Do the Calibration in a WIDE open space . Not in your house, your garage, near your car... - DO NOT carry ferro-magnetic mate rials with you during calibration such as keys or cellular phones. - DO NOT calibrate in areas that could have high ma gnetic EMI interference such as areas that are close to power lines, cell phone towers, parking structures, reinforced concrete or steel reinforcements underground. - DO NOT calibrate beside massive metal objects ( cars, buildings, fences, buried pipes & cables, etc).

Note: Compass Calibration can now also be initiated from DJI Vision - Settings page instead of using the S1 Switch.

Here are some interesting videos to watch and learn from:

- Dji Phantom 2 Compass Calibration Procedure

- DJI Phantom Tutorial - Easily calibrate the compass

- DJI Phantom 2, Vision, Plus: Compass Calibration. How to, where to and some of the why...

Need to Know: (Quote from srandall25) Sometimes the compass can get out of calibration to the point that even the assistant software cannot calibrate the co mpass (it’s probably magnetized and you n eed to degauss it). If that’s the case, a manual intervention with a physical magnet is necessary to bring the compass back into range that the assistant software can deal with. This video: DJI Phantom Resetting the Compass when Calibration fails or this one: Compass Calibration Fix does describe in detail how to fix this

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# Take Good Care of your Compass

According to DJI one possible cause of a fly-away is a conflict between Compass & GPS data as a result of an improper compass calibration. It's been theorized that the conflict generates an error which accumulates until the Autopilot attempts to reorient and/or reposition the aircraft towards the erroneous "corr ect direction" or "correct position" resulting in the now infamous spin-out or fly-away.

The Compass reads geomagnetic information and assists the G PS (Glo bal Position System) to accurately calculate the position and height of the aircraft. The following discussion will describe in more detail the “intimate” relation between the Compass and the GPS module. This should convince you to make sure y ou calibrate your Compass and take good care of it by not flying in areas where the surrounding might affect its accuracy

.

Pa namon Creel wrote:

The compass identifies the nose position along the vertical axis in reference to earth’s magnetic fiel d and it is needed for the controller to hold position and to fly to waypoints in conjunction with the GPS data since the GPS data alone cannot identify the nose position. E.g. Multirotor with good comp ass calibration is on position hold in the air, Nose position is North, GPS data shows the unit moved to the South, controller will rev up the rear two rotors to correct the unit forward, unit moves forward back to its original position, controller happy. Lets say the compass is now out of calibration it and says the nose is pointing north but in fact it is pointing more towards the West, again the GPS data says that the unit moved out of position to the South, controller thinks that the nose is pointing North therefore revs the rear two props up, since the nose is actually pointing west the unit will now move to the west, controller will see the GPS data out of position to the west thus will fire up the left props to move to the east, but in fact will move to the North,... the story goes on and on causing the unit to circle around the point it is supposed to be at.

Cahutch replied:

I found this explanation of the compass function in position hold very enlightening. If the compass is out of calibration in GPS mode, it can cause the Phantom to circle a point in position hold, or if you try to fly it in any direction, it can cause the Phantom to veer off wildly in a random direction. This happened to me once when I accidentally screwed up my compass and it flew off very fast at a high angle and crashed into the street. Unfortunately at the time I didn't know to try switching to ATTI mode to regain control.

In ATTI mode it may still use the compass for orientation hold, but if your compass is out of whack, it won't try to thrust in the wrong direction to correct its position.

This is probably responsible for many flyaways. If the Phantom is trying stay at a specific position, but is revving up the wrong motors to correct, it will move further and further out of position accelerating away from where it's trying to get back to. The pilot is unable to correct it in GPS mode be cause the phantom doesn't know it's pointed in the wrong direction. When you give control input in GPS mode you change the GPS coordinates it's attempting to stay at but the original problem is still there so it just co ntinues to fly off in the wrong direction.

So many lost or crashed Phantoms all because of a bad compass calibration. And switching to ATTI mode as soon as the problem started might have saved them.

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# How to avoid Flyaway

A flyaway is a scenario where the Phantom pilot will suddenl y lose control of the Phantom during a flight resulting in lost or damaged units.

(Quote from Visioneer) “Every new technology must have a boogey-man, and for the Phantoms it's "flyaway". The classic flyaway is described as follows, "I did everything right, and was having a great flight. Then it started acting hinky and I couldn't get it to respond. I tried everything I could think of, and finally switched off the transmitter to activate RTH ... but it just flew off to who knows where". There is much discussion on the cause of flyaway and there's a multitude who blame design faults. There are probably also as many folks who don't buy the design flaw theory and suspect pilot error of some kind, generally in the set up or pre-flight routine. DJI has tweaked the firmware to mitigate some types of interference issues, but the problem is there's been no real study of the failed craft (most are not recovered) so no one really KNOWS what the cause(s) may be. The best (only useful?) advice to date is to make sure you have loaded the best firmware (transmitter and Phantom), follow the pre -flight routine religiously, avoid flying in areas with potential electromagnetic interference, let the Phantom hover a few feet off the ground for several minutes at the beginning of each flight, and watch closely for the loss of GPS lock or any unexpected behaviour (e.g., doing its own thing or not doing what it's told). In the case of any unexpected behaviour, get her down now and start over.”

Be sure you watch: How to avoid DJI Phantom Fly-Away and DJI Phantom "Flyaways" - Simon's take on the subject or this DJI Phantom 2 - How-To Avoid Flyaways, Update

There are basically 3 main things y ou need to perform before taking off:



### 1. Calibrate Your Compass You should always remember to calibrate your compass. DJ I will never really know where every Phantom will land in the world, as they shipped to different countries. As you would expect, there are different declinations of Magnetic North around the world. So it is important to calibrate the compass when you fi rst get your DJI Phantom. This process will tell the Phantom exactly where it is in the world. See the “Compass Calibration” Section for details.



### How to tell if your DJI Phantom needs calibration? 1. The Phantom wants to fly in a circular pattern. For exampl e, if you fly forward and stop but the Phantom then starts to fly in a circle and looks like its looking for an area to stop. It’s time to calibrate

2. If you fly forward but the Phantom flies to the left and if you fly back and it flies to the right. This indicates that the GPS and compass of the DJI Phantom is conflicting with each other. Time to calibrate.



### 2. Set Home Point Before you take off, be patient and allow the DJI Phantom to find and mark its home point. It needs time to identify satellites in the sky to pinpoint s its location. Don’t just plug in the battery and take off. Let it sit on the ground – up to 2 minutes and make sure you see blinking green light for at l east 10 to 15 seconds. This tells you that it has successfully received signals from GPS satellites.

The DJI Phantom needs a minimum of 6 to 8 satellites detected for a minimum of 10 seconds before it can really marked its home point.

When the DJI Phantom flashes rapid green lights after take off, you know that it has marked its home position.



### 3. Watch out for EMI Be aware of any possible high electromagnetic interference in your location. Before taking off check and look out for high power lines and cell phone towers near you, avoid these at all cost. If something is transmitting a similar frequency (2.4Ghz/5.8Ghz) as your controller and has a hi gher signal. It will take over the DJI Phantom controls resulting in possible Flyaway.

Remember to update your Phantom firmware to the latest version as the software developers at DJI are constantly looking for better ways to provide you with an enjoyable and safe flying experience.

Final point is exercise good judgment and common sense. If you notice your Phantom is doing weird things, just be cautious and land as soon as possible. Better be safe than sorry.

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# Recovering from a Flyaway

(Text from BenDronePilot)

So you're flying your Phantom on a nice or not so nice day. Enjoying your flight and suddenly the worst happens. It begins to do things it's not supposed to do and or takes off on its ow n. Following these helpful tips should set you straight.

1) Take a deep breath

2) Don't panic

3) If it begins to fly away you can panic now. (just kidding) please refer back to steps one and two.

4) If you have Naza-M enabled and your bird begins fl ying erratically that could be a GPS lock and or a compass problem. Switch to ATTI mode to help stabilize y our plane and bring it back IMMEDIATELY to land.

5) When flying, if you see your bird behaving in any other way that feels out of the "norm" for you then immediately fly your bird back, if you have control or land it wherever you can in a safe place and walk to it.

6) Your Phantom will keep a log of its last known GPS posi tion as long as you have stable Wi-Fi. Keep the Wi-Fi range extender pointed as directly as possible towards your Phantom to maintain Wi-Fi and thus GPS location within the DJI app. Also make sure your Remote Control antenna is pointed straight up and not sideways as seen in many people videos.

7) Reference how much battery life is remaining before the crash so you can have an idea of how far it may travel should it be in the process of flying away from you. Also note the Radar screen of where its current position is relative to you, should you not have an actual Visual of your Phantom. Again making sure to try to keep your Wi-Fi range extender pointing in its direction to ma intain connection as long as possible.

8) Flip S1 switch down to FAILSAFE or turn off Remote C ontrol at last resort to activate the failsafe return to home function. Keep in mind that if you're below 20m/66ft when hitting Failsafe, the Phantom will climb up to 20m/66ft, so it there are obstacles (higher th an 20m/66ft) between you and your Phanto m then your Phantom WILL run into said obstacles as by default it flies in a straight line above the home position before descending. That’s why it’s always a good idea to climb up (if possible) before hitting the Failsafe.

Your bird is on the ground now. Steps for recovering a do wned Phantom once you believe it's on the ground. It is of vital importance you begin your search IMMEDIATELY to take advantage of certain features of your Phantom that you can use as a means to locate it.

1) If you had a Visual of your Phantom as it reached the ground run to it immediately.

2) If you didn't have visual range but had a Wi-Fi connection, refer to the last known position using either the “Radar Screen” or “Find my Phantom” within the DJI app and go to that location as a starting point for your search.

3) Call some friends to help you search.

4) Provided you've not lost power to the Vision Camera in your fly away or crash event, you can take advantage of the Visions Wi-Fi connection as a means to track it from greater dist ance. It would also have been helpful if the vision's WiFi itself wasn't hidden as it would make this process a bit easier . But what you will do is circle the perimeter of the last known location and cycle the power on the Wi-Fi repeater fr om time to time, then try to make a connection to your Phantom. Keep doing this at set intervals and with the Wi -Fi repeater antenna pointing in different directions. Wait about 30 seconds to a minute after each power up and then try to connect wi th your smart phone. If you make the connection it's a simple matter to find your Phantom by using the Find you Phantom function in the app.

5) Continue searching in a grid pattern, fanning out if you have more than one person looking. You should be constantly trying to regain a Wi-Fi connection as you do this. Also ask any bystanders if they saw your Phantom flying and or landing anywhere.

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# Naza-M and IOC: Why and How

This is one (if not) the best description of Naza-M and IOC. Source: http://www.pattayadays.com/2014/03/naza-mode-on-the-phantom-2-vision/

The Phantom 2 Vision is a fine machine. But the documentation can be sparse in places, and hard to track down. Consequently there is a feature of the machine which you may never have heard about, but which gives you so many more flying options; or you may have heard about it but can either not find out how to enable it, or are keeping away because DJI tells you it is for advanced fliers only. Nonsen se; it’s called the Naza-M and your flights will be more pleasurable and safer if you have it enabled.

First I will tell you what it does; then if you like the sound of what it can do, I will tell you how to enable it.

By default your Phantom is set in Vision 2 mode. In this mode, the two shiny switches on top of the transmitter serve no purpose (apart from the right hand one which you frantically toggle as if attempting to bring it to orgasm in order to initiate the compass calibration mode). So when you fly, it doesn’t matter what position the switches are in.

In Naza-M, these 3 position switches offer a number of functions; with “normal” flight being achieved with both switched in the up position. And this is why DJI says that this mode is not for beginners; because apparently beginners are not capable of checking that the switches are up before flying. Assuming you have the intellect to ensure that the switches are in the upright position before flying, then Naza-M may be for you.

So, switches up and start to fly, and the Phantom will fly exactly the same in Naza-M as it did in Vision/Phantom mode.

Now let’s play with the switches, starting with right hand si de (S1). In the default top position you are flying in GPS mode, meaning that the Phantom will attempt to maintain the same position in space when you take your hands off the stick. Move the switch to the middle position and you are now flying in Attitude mode, or Atti for short (or A if you are really trying to abbreviate to the maximu m [or max, or M]). In this mode, your Phantom will a ttempt to main tain height and direction by means of the barometer a nd compass; but GPS is switched off; so your craft will drift with the wind (if there is no wind at all, you probably won’t notice any difference).

Why would you want to use this? Maybe you have been flying upwind. For an easy return, flip it into Attitude mode and let it drift back to you. Wind direction permitting, it can also be useful for smooth video. Fly upwind, start your video, and then turn on Attitude mode and let the video run as your Phantom is born along on the wind.

The bottom position of S1 initiates the Failsafe/Return to Home (RTH) procedure; whereby your Phantom climbs to 20 metres if it is lower than that, flies back to the starting point and then gently lands at your feet to the applause of admiring onlookers. Normally, Failsafe triggers on when you ha ve lost contact with your Phantom; but there are times when you may want to initiate it even though you have a connection. The first is to impress those onlookers (I have been guilty of that); and the second maybe when you have ha d enough flying and just want to let your Phantom come home on its own. The problem is that in Phantom mode, th e only way you can trigger Failsafe is to turn off the
transmitter. This is all well and good if your Phantom does then return to home and land; but if it decides to bugger off instead, there is nothing you can do to reconnect; and you wi ll left looking like a fool in front of an expectant crowd.

In Naza-M, the bottom position of S1 will initiate Failsafe/RTH, but you can regain control by flicking up the switch at any time. Much better.

On the left we can find S2, home of the Intelligent Orientati on Control (IOC) functions. In the up position (or in Vision 2 mode), IOC is off. And there you are, your Phantom a zillion metres high and a zillion metres away; and you want to bring it home. To do that, you need to know where the front of the craft is pointed so you can bring it back towards you. Unfortunately, given the shape of the thing, it can be impossible to know which is the front just by looking at it, especially from a zillion metres away. So you have to squint at the display on the phone to work out orientation (assuming you haven’t lost WiFi contact) and then mentally ca lculate which stick to throw to bring it back; by which time the batteries have died and it has landed in a swamp.

Hello S2! Flick the switch to the bottom position and you are now in Home Lock mode. Then pull back on the right hand stick and the Phantom will return to its starting point, irrespec tive of the direction in which it is pointed. I find this massively useful. Whenever I have finished with a flight, I turn on Home Lock and just bring it home; so easy.

Page 32The middle position is less ob viously useful. It’s called C ourse Lock and when it is enab led, the Phantom will respond to the sticks as if it is aligned in the direction it was facing at time of take off. So if your Phantom was facing East when you took off and is now pointing North, pushing the right stick forward will send it north. Flick onto Course Lock and pushing the stick will send it East.

Still, access to Atti, Failsafe, Course Lock a nd Home Lock modes is worth having, so How do you switch to Naza-M?

Connect your Phantom to your computer and turn it on. Start up the Assistant software and on the top right hand side you will see a button set to “Phantom”. C lick on it to change to Naza-M: read and u nderstand the warning then proceed.

Next, as you flick S1 you will see the options change in the control mode switch. In the down position you will see you
have selectable choices

.

Page 33Make sure you have selected Failsafe; which triggers the Return to Home mode. Another option is Manual, which removes all the limits of the flight system and allows advanced pilots to perform rolls and other aerobatics, and pilots like me to convert my Phantom to a pile of plastic in a couple of seconds. Unless you’re a very experienced flyer, you probably don’t want to try Manual mode.

Need to Know: After switching to Naza-M, you must also activate IOC. Select the ADVANCED tab and place a
checkmark in the IOC box. Without this step, the S2 switch won’t do squat

.

Turn off the Assistant software and turn off and disconnect the Phantom. You are now all set to use Naza-M. Just remember to check your switch positions before turning on your Phantom ( S1 and S2 must be on TOP position ).

Look under the “What to do Be fore your First Flight OR After any Softwar e/Firmware Update OR After a Crash” section for some nice tutorials on how to turn Na za-M /IOC on and to what expect when th ey are on. Also be sure to read the “Know your S1/S2 switches” section.

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# Failsafe

Manual Failsafe ( Always give extra elevation before you hit Failsafe!!!) Switch S1 into the bottom "Failsafe" position (Just turning off the Remote Control will accomplish the same thing). Phantoms tail lights turned rapid Yello w flashing followed by it ascending to 20m/66 feet or to your manually set RTH altitude (If its height is higher than that, it will stay at that height), flying over its orig inal "Home Point”(RTH), pausing a bit before descending (~15 sec). If Needed: before allowing it to land put S1 switch into the center position(ATTI) to regain control followed by switching S1 to the top position for "GPS" mode.

Need to know: With the latest DJI’s update, we now have the ability to change the default Return to Home(RTH) altitude (20m/66ft) using the VISION app or the Assistant software.
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### This was taken from the Naza-M Guide. It gives a more detailed description of Failsafe

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# IOC Flight - Course Lock & Home Lock

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