Why would a compass error disable GPS?

Orientation (compass data) and position (GPS data) are different but related.
When the Spark is moving and getting position information from the GPS that tells the Spark that it is travelling in a different direction from what it's getting from compass data, The Sparks programming can't work with the data conflict.
The solution is to drop data from one source and since the Spark can't fly without a compass but can without GPS, it's the GPS data that gets dropped.

There have been some compass problems with Sparks lately or your issue may have been related to something you did.
I'd be interested in these cases to see where aircraft took off from (was there mag interference close by) When was the last time you calibrated your compass and why.

This may help give some answers to those who have had these problems

Why should the spark not be able to fly without a compass?

Dirk52 Posted at 2017-8-3 10:28
Why should the spark not be able to fly without a compass?

To be clear, positioning take 2 sensors into account which are GPS and COMPASS.
If one or both of them fail, then there will be no positioning available.


You can imagine your self, GPS is like you got a map, and compass is like you know where is you're heading at the moment.

If you know your position on the map, and you need to go some where else on the map, how can you decide which way to go if you don't know which dirrection are north or south or west or east?
It applied vice versa. If you know your current heading, but you dont have any idea where are you on the map right now, how would you do to get into your desired destination?

hallmark007 Posted at 2017-8-3 11:02
To be clear, positioning take 2 sensors into account which are GPS and COMPASS.
If one or both of them fail, then there will be no positioning available.

For positioning you don’t need a compass. Only for automated navigation.

So it is clear when gps is lost the drone switches to atti. No positioning possible.
When there is a wrong compass the drone  also switches to atti to prevent a flyaway. When you get two different headings you can’t know which one is right. So it is safer in atti mode.

Dirk52 Posted at 2017-8-3 11:27
For positioning you don’t need a compass. Only for automated navigation.

So it is clear when gps is lost the drone switches to atti. No positioning possible.

Although I don't agree with compass is only for automation, your spark can't even fly straight without compass. The rest of what you said is just repeating what I said.

hallmark007 Posted at 2017-8-3 11:39
Although I don't agree with compass is only for automation, your spark can't even fly straight without compass. The rest of what you said is just repeating what I said.

You know what a IMU does?

Dirk52 Posted at 2017-8-3 11:27
For positioning you don’t need a compass. Only for automated navigation.

So it is clear when gps is lost the drone switches to atti. No positioning possible.

Compass is definitely used for more than automation.  Calibrate your compass poorly then try to fly your drone.

Dirk52 Posted at 2017-8-3 11:41
You know what a IMU does?

Your obviously trolling again so I'm not interested in getting into it with you, so I will explain what an Imu is then you can go and troll somebody else, and you obviously don't or else I have proved my point that you are trolling again..

This I wrote for people who wanted to know over at Mavic, but remains the same for spark or phantom or MATRICE.

IMU "Inertial measurement unit" .

As far as I see it, IMU calibration on a level surface updates a table of values the flight controller software uses as a reference for a level stationary hover. From there the craft responds predictably to flight commands.  It also likely measures any sensor noise and thermal drift so that these technical imperfections are accounted for when using IMU sensor data in flight. - this is likely why there must be no vibrations during the calibration process.


Bad IMU calibration could cause drift and attitude issues as the flight controller fights to hold the craft in what it thinks is the correct attitude as opposed to the correct physical attitude.


The IMU usually has 2 types of sensors – angle and acceleration and in turn 3 sensors of each type measuring in the X,Y and Z axis. These sensors can, through vibration, aging, impact etc, drift in their response over time and thus an IMU calibration will establish a new reference for the IMU’s level/stationary state that the flight controller can work with to restore stable flight.


Think of calibration as the bringing back into line the measured craft attitude with the true physical craft attitude.


As to how often an IMU calibration is needed, Refer to your manual ; certainly

method007 Posted at 2017-8-3 11:46
Compass is definitely used for more than automation.  Calibrate your compass poorly then try to fly your drone.

Sure uses dji the compass for more than automation. You can’t even lift off with bad compass. But you don’t need it for flying. The compass gives you only the course how your drone is heading on the map. This is important for all intelligent modes and rth and so on. The imu can hold your aircraft on perfect heading, but you have no idea in which direction the heading is. So a loss of compass doesn’t mean your aircraft will drop.

To say you need a compass or the drone can’t fly or fly a straight line is not correct.

Dirk52 Posted at 2017-8-3 11:53
Sure uses dji the compass for more than automation. You can’t even lift off with bad compass. But you don’t need it for flying. The compass gives you only the course how your drone is heading on the map. This is important for all intelligent modes and rth and so on. The imu can hold your aircraft on perfect heading, but you have no idea in which direction the heading is. So a loss of compass doesn’t mean your aircraft will drop.

To say you need a compass or the drone can’t fly or fly a straight line is not correct.

Ridiculous Imu holds your Aircraft on correct heading, I don't think you know what your saying Imu does a completely different job with your aircraft. Read my last post.

hallmark007 Posted at 2017-8-3 11:49
Your obviously trolling again so I'm not interested in getting into it with you, so I will explain what an Imu is then you can go and troll somebody else, and you obviously don't or else I have proved my point that you are trolling again..

This I wrote for people who wanted to know over at Mavic, but remains the same for spark or phantom or MATRICE.

You see that the imu can hold the heading with no problem. So it is wrong what you are saying you can’t fly with no compass or no straight line.
All little drones without a compass are just rotating around themselves? I think you are trolling..

hallmark007 Posted at 2017-8-3 11:55
Ridiculous Imu holds your Aircraft on correct heading, I don't think you know what your saying Imu does a completely different job with your aircraft. Read my last post.

It CAN hold the heading when compass is lost! Read and understand.

Dirk52 Posted at 2017-8-3 12:02
It CAN hold the heading when compass is lost! Read and understand.

It can't hold a heading without input from controller so if you bank left and then straight it's Imu that gets signal from cpu to straighten aircraft they same way as when you let go sticks your Imu tries to maintain a level hover.

Your flogging a dead horse here again , don't be afraid of learning something,

hallmark007 Posted at 2017-8-3 12:06
It can't hold a heading without input from controller so if you bank left and then straight it's Imu that gets signal from cpu to straighten aircraft they same way as when you let go sticks your Imu tries to maintain a level hover.

Your flogging a dead horse here again , don't be afraid of learning something,

You have no idea what you are taking.
How fly all the drones without a compass?

Dirk52 Posted at 2017-8-3 11:53
Sure uses dji the compass for more than automation. You can’t even lift off with bad compass. But you don’t need it for flying. The compass gives you only the course how your drone is heading on the map. This is important for all intelligent modes and rth and so on. The imu can hold your aircraft on perfect heading, but you have no idea in which direction the heading is. So a loss of compass doesn’t mean your aircraft will drop.

To say you need a compass or the drone can’t fly or fly a straight line is not correct.

If your compass is calibrated wrong, you don't fly straight.

I'm talking about an actual existing product - you seem to be talking about theoretical products?  Is there a drone DJI has made where if the compass is messed up you can still fly it in all directions without issue?

method007 Posted at 2017-8-3 12:09
If your compass is calibrated wrong, you don't fly straight.

I'm talking about an actual existing product - you seem to be talking about theoretical products?  Is there a drone DJI has made where if the compass is messed up you can still fly it in all directions without issue?

https://www.rcgroups.com/forums/ ... 325&postcount=4

method007 Posted at 2017-8-3 12:09
If your compass is calibrated wrong, you don't fly straight.

I'm talking about an actual existing product - you seem to be talking about theoretical products?  Is there a drone DJI has made where if the compass is messed up you can still fly it in all directions without issue?

You know google?
https://www.rcgroups.com/forums/ ... 7045325&postcount=4
Better you read everything about drones and compass:
https://www.rcgroups.com/forums/showthread.php?2847425-Will-it-fly-without-a-compass

method007 Posted at 2017-8-3 12:09
If your compass is calibrated wrong, you don't fly straight.

I'm talking about an actual existing product - you seem to be talking about theoretical products?  Is there a drone DJI has made where if the compass is messed up you can still fly it in all directions without issue?

He's always talking about theoretical something or other.

hallmark007 Posted at 2017-8-3 12:17
He's always talking about theoretical something or other.

What’s about that?

http://forum.dji.com/forum.php?m ... &fromuid=388548

Dirk52 Posted at 2017-8-3 12:13
You know google?
https://www.rcgroups.com/forums/ ... 7045325&postcount=4
Better you read everything about drones and compass:

Like method said I'm talking about spark, read my post I mention Spark numerous times. Your just doing what you usually do when your wrong.

Your wrong about my opening post your wrong about compass in spark your wrong about IMU, maybe you should read and you might learn something.

It's not that long ago you thought Spark stayed in the air by using front sensors only. I'm still laughing about that one.

Normally people partake in threads to learn or help but you continue to try to disrupt without really knowing what your talking about.

hallmark007 Posted at 2017-8-3 12:31
Like method said I'm talking about spark, read my post I mention Spark numerous times. Your just doing what you usually do when your wrong.

Your wrong about my opening post your wrong about compass in spark your wrong about IMU, maybe you should read and you might learn something.

Oh? Nothing more about the „a drone can’t fly without a compass or can’t hold the heading“?
Go, read and learn something before trying to teach others wrong informations!

Just for you, a IMU can hold the heading and the drone can perfectly fly straight lines in all directions. A compass is not necessary (just wanted from dji).
You started with a wrong opening.. so it needed to be corrected. Mission complete.

And about the spark and staying in the air.. it was a possibility how the spark could manage this. Nothing more. You should better read and understand others posts.Method asked about a dji drone that can fly without a compass, I showed it to him.. again for you, read and understand!

I just want to say for anyone reading this,
IMU can't hold a heading , it can maintain a heading but only with input from controller, if controller pushes stick forward to fly in a straight line then IMU keeps that heading on instructions from controller. So IMU can't maintain heading without controller giving instructions.
So ignore what dirk52 said and also information in opening post is correct for spark.

You also need to ignore his comment about spark not needing a compass, that's about the most ridiculous thing I've heard him say since he said that spark stays in the air only using front sensors.

I just want to say for everyone reading this, read about what a IMU can do.
Don‘t believe what hallmark says about it. He think a imu can‘t hold a heading. So all small drones with no compass and the old nazas were never been flying.
Read my post with the links, read from other people about flying with no compass.
That the spark could fly with no compass is theoretically possible, dji needs only to allow this.
And who thinks dji doesn’t use he imu also for heading should read the topics about „warning imu heading exception“.

Dirk52 Posted at 2017-8-3 13:26
I just want to say for everyone reading this, read about what a IMU can do.
Don‘t believe what hallmark says about it. He think a imu can‘t hold a heading. So all small drones with no compass and the old nazas were never been flying.
Read my post with the links, read from other people about flying with no compass.

WARNING IMU HEADING EXCEPTION , WHAT DOES IT MEAN AND HOW IS IT CAUSED.

Dirk52 Posted at 2017-8-3 13:26
I just want to say for everyone reading this, read about what a IMU can do.
Don‘t believe what hallmark says about it. He think a imu can‘t hold a heading. So all small drones with no compass and the old nazas were never been flying.
Read my post with the links, read from other people about flying with no compass.

He obviously can't find it on google, hehe.....

Since only 2 people are posting in this thread and yet it is getting heated, I will close it. Please feel free to keep the conversation going via PM.