Faster Home Point

[msinger]

If I start up the drone, get the home point and GPS fix and then land it and change out the battery, will all that data "hold?"

No. The home point is set each time the motors are started. It's not an internal setting that is stored/remembered.

 

[G Lee]

Not disputing msinger at all but ive heard the home point mess. before and after motor start.

 

[msinger]

ive heard the home point mess. before and after motor start.

Can you explain some more? I'm not sure what you're trying to say.

 

[Thomas B]

Not disputing msinger at all but ive heard the home point mess. before and after motor start.

So prove it to yourself... take off, let the home point set. Fly 2-3 minutes. And RTH. Then pick up the drone and move, even a few hundred feet, and repeat... the drone wil then RTH to the second location.

 

[G Lee]

Yes sir , i power on rc then ac wait for update mess. then start motors. But ive also done the same and start motors and wait for the update and then get it so from my exp. it works both ways.

 

[Meta4]

Still looking for an answer to this question....If I start up the drone, get the home point and GPS fix and then land it and change out the battery, will all that data "hold?"

Yes, that should give you a hot start.
The GPS almanac data will be up to date allowing the GPS to acquire satellites quickly and record your new home point quickly.
Try it and see.

 

[Meta4]

Not disputing msinger at all but ive heard the home point mess. before and after motor start.

He meant power up rather than motor start.
The recorded home point is lost when you power down and a new one is recorded after powering up, as soon as your Mavic gets a good location fix.

 

[G Lee]

So far as the OP , i tried both ways props not on and props off and diff. locations tonight but nothing speeds up the homepoint update. I think ZX14R said it all. grasshopper way works. Thx all for replies.

 

[Mike4884]

There are always myths to shoot down.

The IMU has nothing to do with GPS and makes no difference at all.

Cloud cover makes no difference to GPS.

Your drone's GPS acquisition time will vary.
If you have a clear, unobstructed skyview and have flown recently in the same area, the GPS will know where the sats are already and get a fast lock. (hot start).
If it's been a longer time since the drone was used, it will take longer (cold start).

Time to first fix - Wikipedia

en.wikipedia.org

If you want to have a fast startup, you should start the drone and get a good fix and shut down.
Then when you want to fly again soon after, it's going to get GPS faster.

While this is true.... He might not know that his IMU's are taking a while to warm up....maybe acquiring satellites is not the problem. I remember I had a phantom 4 that would take about a minute and a half to warm up and then finally give me gps go ahead....(pretty sure this does this after IMU warms up)
So I calibrated IMU while it was cold and startup times were significantly faster 20 to 30 seconds IMU would be done warming up and I would get GPS lock right after. Don't know why that made a difference but it really did so every single flight after.

 

[GadgetGuy]

Yes, that should give you a hot start.
The GPS almanac data will be up to date allowing the GPS to acquire satellites quickly and record your new home point quickly.
Try it and see.

Certainly works for me! Get your GPS almanac data updated for the location with a spare partially depleted battery, and then swap batteries with a fresh 100% battery for fastest satellite acquisition to maximize flight time! This happened to me by accident the first few times, when I grabbed the wrong battery initially. Now I always carry a spare battery I don't intend to fly with, just for updating GPS almanac data.

 

[G Lee]

Yes i had slow start with my P3A and did the IMU cali and it seem to help. I remember someone stressing the importance of it being as cold as possible for that cali to be effective. So i did the IMU cali on the M2P , no joy.

 

[gnirtS]

Homepoint is set (i) when it first gets a good GPS lock and then (ii) again on takeoff IF you've moved the drone a bit between those times.
IT certainly downloads and saves almanac data (as all GPS should) to speed up an initial fix if possible, as someone else mentioned, lock times after a battery swap are significantly faster.

IMU calibration will do absolutely nothing for home point (and wouldnt be on a P3 either). Its entirely GPS based. Ultimately if you have a clear sky it'll be faster than one with buildings, trees and so on blocking quadrants of it.

 

[RadioFlyerMan]

Still looking for an answer to this question....If I start up the drone, get the home point and GPS fix and then land it and change out the battery, will all that data "hold?"

My first GPS acquisition of the day takes the usual long time to reach a minimum of 10. With subsequent flights within a few minutes after changing the battery, the GPS sats are still there with little to no wait (and I live in a forest). Since I'm using Super-Patcher, it's common to see 22 to 27 sats at altitude.

 

[NatureMate]

So i could take off and then reset home point to RC??

 

[GadgetGuy]

So i could take off and then reset home point to RC??

As long as you have GPS capability in your device attached to the RC. If an iPad, either a cellular iPad (cell contract not needed) , or a BT connected GPS device on a WiFi only iPad.