Betaflight GPS Rescue mode is similar to “Return to Home” on a DJI drone. It is designed to bring your FPV drone back to the launch point and land it automatically using GPS when your video feed or radio signal gets sketchy, or in the event of a failsafe.
Before Betaflight 4.4, Rescue mode was able to bring your quad back close to the launch point, you have to take over control or the drone would just drop to the ground. In the new version, Betaflight has added the ability to land itself!
However it might not land exactly where it took off, the accuracy depends on your GPS. In my testing it’s close enough, usually within 3-5 meters error. It’s an extremely useful feature in Betaflight nonetheless, especially for long range flying, I’ve lost count how many times GPS Rescue mode has saved me in the past.
Anyway, Rescue mode in Betaflight should be treated as experimental. Do not expect to get your quad back every time, there still a chance you might lose your quad.
Table of Contents
Hardware Requirement
These are the GPS modules I have been using with good results. I stop using BN180 because it’s not programmable to get better performance.
Beitian BN220 – small and affordable, get it here:
- AliExpress: https://s.click.aliexpress.com/e/_DENus9Z
- Banggood: http://bit.ly/2nD6QxP
- Amazon: https://amzn.to/3Xelr1F
Beitian BN880 – has a built-in compass, bigger but slightly better performance, get it here:
- AliExpress: https://s.click.aliexpress.com/e/_Ddxvybl
- Amazon: https://amzn.to/2BctUgg
Some flight controllers come with onboard barometers. It’s not required for GPS Rescue mode to work, but it can significantly improve altitude control. Barometer is used to calculate altitude. If you don’t have this, altitude can be calculated from GPS, it’s just won’t be as accurate as having a dedicated barometer. Some FC with built-in barometer are: Rush Digital F722 V2, Speedybee F405 V3 and Speedybee F7 V3. When you are conformal coating your FC, do not coat the Barometer because it has a hole on it, covering the hole will make it stop working properly.
Compass is not required in Betaflight Rescue Mode, direction is calculated from GPS data. Actually I would isable compass (magnetometer) unless you have calibrated it and confirm it’s working as expected, otherwise it might cause more problems than it solves. In my testing, Resuce mode worked just fine without Compass to be honest.
Software Requirement
Only from Betaflight 4.4, Rescue mode has the ability to land itself. Follow this tutorial to flash your FC to Betaflight v4.4.
Make sure Accelerometer is enabled (in the Configuration tab in Betaflight configurator), and that Angle mode is working as intended.
And you should Setup GPS module in Betaflight (this tutorial includes all the wiring and basic configurations).
To be able to use GPS Rescue mode, you must have at least 8 GPS satellites before take off (by default). You might be able to get it to work with just 6, but the more satellites the more accurate and reliable Rescue mode will be.
To know how many GPS satellites you have, enable the “GPS Sats” OSD elements.
Alternatively you can check this in the Setup page in Betaflight Configurator (under GPS).
What Happens when Rescue Mode is Activated?
Check out GPS Rescue Mode in action:
There are 5 phases to Rescue.
Ascend
The quad climbs to the set altitude (or to the maximum altitude during that flight).
Rotate
The quad turns to home direction.
Fly Home
It starts to fly toward the launch point. It’s not going to be a smooth cruise, it might jiggle left and right as it’s trying to figure out the direction, but it will eventually get home.
Descend
It will hover within a 5x5m area of the launch point, and starts to decent slowly. It won’t be a smooth descend, in my experience the quad would actively trying to slow down during descend, and so the motors make pulsating sounds.
Land
When the drone touches the ground and it will disarm automatically. The motors are terminated on impact, not on altitude.
How to Interrupt Rescue Mode
If you activated Rescue mode using a switch, you can take back control by disengaging that switch and resume flying.
If it’s activated by failsafe:
- the pilot must move the sticks more than 30% to regain control after the radio link comes back after a real failsafe
- wobbling sticks is not needed with a switch induced failsafe, just reset the failsafe switch
GPS Rescue Mode Settings
Settings for GPS Rescue mode are available in the Failsafe tab.
To edit the settings, you need to first select “GPS Rescue” under “Stage 2- Settings“. But if you are not ready to use Rescue mode as failsafe method, just change it back to “Drop” after the configuration.
You have to tweak the settings in Betaflight to make it work for your particular setup and environment. Make sure to check out the Betaflight wiki to fully understand what the parameters do: https://github.com/betaflight/betaflight/wiki/GPS-rescue-mode (this post seems to have been removed, the only resource I can find on github right now is this: https://github.com/betaflight/betaflight/pull/11579).
If after reading the Betaflight WiKi, you still have absolutely no idea what settings you should use, just give the default a try and see what you should change. According to info in the pull request, the default is designed primarily for 5″ freestyle so it might need adjustment on other size drones.
Here I will go through the settings and share with you what values I use on my 5″ freestyle drone and why.
All the settings are also accessible In CLI, enter get gps_rescue and you will get a whole list of GPS related parameters. But it’s easier to change them in the GUI (in Failsafe tab).
Angle – This is the maximum angle the drone can tilt in degrees. In strong wind, you might need a higher angle to achieve the desired speed. This is especially true for smaller quads. However if the angle is too steep the drone might struggle to stay in the air so it also depends on the power of the quad. If you set a big angle you should expect some overshoot.
If you are not sure, just try the default value and see how it perform in testing.
You need to enable Accelerometer and need to be calibrated/trimmed properly for this to work accurately. If your ACC is faulty, rescue mode might not work correctly for you. Verify by flying in Angle mode.
I just leave it at default, 40, it works well for my 5″.
Initial Altitude (meters) – at what minimum height the drone returns home relative to the take off point. It should be high enough to avoid trees, buildings and power lines. But not too high it takes a long time and too much battery to ascend. I increased it to 50m as we got some tall trees and hills here.
Descend Distance (meters) – at what distance from home our drone starts to descend. I leave it at default.
Minimum distance to home (meters) – The minimum distance to home when rescue mode is allowed. There’s a hard limit in Betaflight 4.4, 20m with 2m altitude, you can’t set it lower than that.
I leave it at default, 30m.
Ground speed (meters/second) – Note when entering this value in GUI, the unit is different than CLI (which is cm/s). This is the speed at which the quad travels during Rescue. The default 5m/s is 18km/h which I find too slow, I doubled that to 10m/s which is 36km/h. The quad’s travel direction would be more accurate and update faster in higher speed (when a compass is not used and the orientation derives from GPS). Do not set it to lower than 2m/s or orientation won’t work.
Throttle minimum, Throttle maximum, Throttle hover – these are the min, max and hover throttle values you want to use during Rescue mode. Set maximum so the quad isn’t too fast/jerky (it should be above your hover point), set min to keep the props spinning at a reasonable rate (it should be lower than your hover point).
To set hover point, you need to determine an accurate value. Test your quad and see at exactly what throttle it hovers (just enough throttle to keep the quad afloat), literally every quad is different. Use the “Throttle %” OSD element to get the exact value instead of just guessing. According to info in the pull request, “the correct value should cause the quad to climb a bit while in level mode… If these values are set too low, the quad will drop early in the rescue – possibly into the water!”.
Ascend rate, Descend rate (meters/second) – pretty self-explanatory. Adjust these based on your environment, weather condition and your quad’s power. I normally just leave it to default for my 5″ and it works pretty well. If you use Li-ion packs or low C-rating LiPo, maybe use a lower Ascend rate.
Minimum Satellites – Your quad won’t arm if the GPS has fewer satellites than this value. The recommended number of Sats is 8 for reliable rescue mode. 5 or 6 might still work, but it will be sketchy. For me it only takes a minute or two to get 10-20 satellites, so I just leave it at the default, 8.
Note that if you take off before the GPS reach the minimum amount of satellites, it won’t know where home is exactly. More satellites means better position accuracy, you can reduce the number of sats but the position accuracy will go down.
By enabling “Allow arming without fix“, you can still arm the quad when satellite locks is below the “minimum Satellites” number. I usually enable this because it’s more flexible – I don’t have to wait around when I just want some quick flights in my familiar local park. But whenever I am flying in a new spot, over water or diving down cliffs, I always wait for satellite lock.
Beware that GPS Rescue WILL NOT work for that flight if you arm before getting a satellite lock (because it doesn’t know the home position).
If you have trouble getting these many sats (or it takes a long time), check out my tutorial on how to boost your GPS receiver performance. Get a new GPS if you must, they only cost $10-$15, a great investment for protecting your $300 quad!
Altitude Mode – it determines the altitude at which the quad returns home.
- Maximum altitude is the highest altitude your quad was flown during flight
- Fixed altitude is just a user defined value
- Current altitude is whatever height that the quad was at when GPS rescue mode was activated
The option depends on your environment. Maximum altitude is probably the safest option in my opinion, but if you flew way too high in that flight, you could be wasting energy climbing back to that altitude when Rescue mode is activated.
Sanity Checks – when set to “ON”, it constantly monitors GPS Rescue mode conditions, for example:
- is GPS still connected
- are we getting good number of satellite fix
- are we at least 100 meters away from home? (distance can be changed)
- are we getting closer to the home, and we didn’t hit an obstacle
If any of these conditions are not met, it will abort rescue mode and your quad will just disarm and drop to the ground. So yea, it’s not ideal if you are flying over unrecoverable places like ocean or mountains, but generally, it should be on for safety reasons.
The Betaflight wiki also recommends setting Sanity Checks to “Failsafe Only” if you are having trouble with the option “On” during testing. It turns Sanity Checks off when Rescue mode is activated by a switch but only turns it on when it’s in failsafe. This is also my preferred option.
It’s more risky to turn off Sanity Check entirely, you might get an indefinite flyaway. In Betaflight 4.4, there is now a limit of 20s of sanity failure even if all sanity checks are off. It is a safety thing. Never fly with all sanity checks off.
How to Activate GPS Rescue
There are two ways to activate GPS Rescue mode, either by Failsafe, or by a switch on your transmitter.
It’s useful to assign a switch to GPS Rescue as an emergency mode, in situations like losing orientation (e.g. when flying LOS) or your FPV system stops working, you can activate it manually.
Go to the Betaflight Modes tab and add a AUX channel for GPS Rescue Mode.
But the best use for Rescue mode is Failsafe in my opinion. By default your quad just drops to the ground when failsafe happens, how wonderful would it be if it can come back home like a DJI drone? Well here is how to do it.
To set up Rescue mode for failsafe, go to the Failsafe tab in Betaflight Configurator. If you don’t see it, you have to first enable “Expert Mode” option (next to Update Firmware button on the top).
You drone goes into failsafe when you lose radio signal.
In a failsafe there are two stages, your drone will go into Stage 1 first, it will just sits there for a second (Guard Time, you can change how long) before entering Stage 2. This is to see if the signal can come back, if so your control will resume. You can also do different things during Stage 1, like Channel Fall Back (setting each channels to specific values).
If signal doesn’t come back after Stage 1, then it will go into Stage 2 which is GPS Rescue as we have selected above, you quad should now fly home.
It is nice to be able to set GPS Rescue as your failsafe method, but it’s not for everyone as it really depends on the environment. For example I wouldn’t use GPS Rescue mode if I am flying in a forest, bando, stadium or garage. Imagine losing your control link while under a tree, or inside a building. Your failsafe would kick in, and Rescue mode would immediately send your quad into the branches or the ceiling, which isn’t very helpful!
If you have no GPS fix when it failsafes, the quad will (should) just drop to the ground.
Throttle Channel Fallback
The default Channel Fallback setting for Throttle is “Auto”, which drops the throttle to zero when Stage 1 failsafe is activated. When you change Stage 2 failsafe from the default value “Drop” to “GPS Rescue”, in the event of a failsafe the motors will momentarily stop for the Guard Time (1.5 seconds by default in BF4.4). This might destabilize the quad while GPS Rescue kicks in, and Betaflight thinks there’s something wrong as it fails one of the sanity checks and cause the drone to just drop to the ground.
A workaround would be to set the Throttle Channel Fallback setting from “Auto” to “Hold”, so the throttle value is held at its last commanded position for the Guard Time to avoid the motor stalling.
Even better, I normally set throttle to the hover throttle value, center all the roll/pitch/yaw sticks, and put the quad in Angle mode, so as soon as Failsafe happens the quad just levels out and stays there until Rescue mode kick in (if my radio signal doesn’t come back).
Never set throttle to zero in stage 1 failsafe!
How to Test GPS Rescue
Here’s how I test GPS Rescue.
First of all, assign a switch to GPS Rescue and make sure it can indeed bring your quad home as intended. If anything goes wrong, disengaging the switch should give you full control again.
Next, assign a switch to Failsafe in the Modes tab in Betaflight. It emulates full failsafe mode in Betaflight (just like when you lose RC signal). This is a lot safer than testing by turning off your radio, because you can disengage anytime you want using a switch.
Note that this is only for testing GPS Rescue mode, as soon as you finish testing, you should remove it in the modes tab.
Remove all props, go into the Modes tab and verify that Failsafe mode can actually get activated by the switch. At this point your quad will go into Rescue mode, and your radio controls will be locked out. Now check if you can deactivate failsafe and take back control.
When you are testing this on the bench, with the USB cable connected, the Rescue mode box won’t turn yellow like other modes. This is fine as long as the small yellow bar can move to the activation range.
It’s useful to have these GPS related info on your OSD, they will help you understand what your quad is doing. You can also have Flight Mode enabled, it’ll say “RESC” when Rescue mode is activated, “Air” when your quad is in rate mode, and “Angle” when it’s in angle mode.
Now test it in an open field with no obstacles and people.
Make sure you have enough locked satellites in the OSD before arming.
Fly in a straight line, 100-200 meters away.
Activate Failsafe mode using the switch, shortly your quad should enter GPS Rescue mode (watch the flight mode in OSD).
Pay attention to the home arrow in Betaflight OSD, if it’s pointing up, it means you are flying home. If it’s pointing down, means you are flying away from home. The arrow might be pointing the wrong direction at the beginning, this is normal. Just make sure the quad isn’t flying the complete opposite direction.
You can quit failsafe mode by flipping the switch at any time and resume full control.
If you don’t disengage, it will carry on flying home. When the quad reaches home, it will hover for a bit and starts to slowly descend but the motors will be pulsating… until it hits the ground and disarms automatically.
Repeat the procedure again and again until you are feeling comfortable with it.
Once you are done with testing, remove Failsafe from the Modes tab.
Tips
Words from Betaflight Devs
I recommend 10 satellites. [And] Wait for 30s after [you have] 10 satellites for altitude to stabilise [before taking off].
Always confirm normal GPS Rescue behaviour at the start of a critical flight by testing with the failsafe switch. Set the switch to immediately enter Stage 2. You can enter and leave GPS Rescue via the switch with immediate on and off effect. Check that the quad rotates and flies towards home and does the right things before you are so far away that a true failsafe may occur.
ALWAYS CHECK that the Home Arrow points directly back towards home after takeoff! Sometimes, if you take off and spin around during arming or immediately on takeoff, the quad’s attitude information can become corrupted, and the Home Arrow can point the wrong way. It’s best to arm cleanly and fly away from Home in a straight line at a reasonable speed immediately after takeoff. Watch the Home Arrow carefully to ensure it quickly points back to Home. If the Home Arrow points the wrong way when a failsafe occurs, the GPS Rescue will initially fly off in the wrong direction, and in some cases, you may lose the quad.
Wrong direction in Rescue?
Without a compass, your quad can still work out direction using GPS coordinates. By flying forward the drone can calculate which way it’s going by comparing the current position and the previous position. That’s why at the beginning, your quad might be wandering around or even flying towards the wrong direction but eventually it should correct itself. If your GPS signal is weak or updating too slowly it can take longer to correct.
If you are using a compass and it’s flying the wrong direction, then maybe there’s something wrong with the compass, or maybe it’s not calibrated properly. In this case try turning off the magnetometer (compass) and try again. If it works now, it proves your compass is the source of the problem.
If your yaw is jerky during Rescue mode, your GPS might be updating too slowly (e.g. 1Hz), try to increase it to 5Hz or even 10Hz following this guide (only works on certain GPS modules).
Edit History
- Oct 2018 – tutorial created
- Aug 2020 – updated, GUI changes, CLI parameter names changes, added throttle min/max/hover values
- Feb 2023 – updated for BF4.4 (with auto landing capability)
91 comments
Very coo! What happens if you have no satellites and the quad goes into failsafe?
it should just drop to the ground.
Merci beaucoup pour cette belle explication 👏👏👏
Hello Oscar!
Thank you for your post, it helped me a lot! I could set up the GPS properly, but after I updated the firmware for the Betaflight 4.3, the GPS is not working anymore. No gps sign, nor any gps data on the gps tab. Do you know any solutions? I used the same settings as before. (HGLRC M80pro with a geprc cinelog 35 flight controller and caddx vista.)
Thank you for your help!
it’s really great that you take the trouble to write all this information together instead of putting it all in one youtube video. thank you very much for the hard work. please go on!
hej i have the tyro 119 with the accst taranis x9d
build it all and it all works
if i install all the modes on bf it works until i come to gps rescue or failsafe
then nothing on the quad will work even if i put all the modes back
need to restart the quad and the taranis and start all over again.
then if i do all the basic stuff the quad and taranis work and i can fly but nog with gps if i put it on it is okay but when i want to set the failsafe or gps rescue it is again blocked up and need to restart
WHO CAN HELP!!!
I have the same exact problem, it will get stuck in rescue / fail-safe mode and wont come out when you flip the switch or turn on the radio and all controls are locked out until FC is rebooted
Hi Oscar, I saw a reviewer saying that GPS rescue triggers on critical low battery? Is this true?
Hi Oscar, some say put throttle in hold some say leave it in auto, I trust you so you tell us please
Hi, is there a way to warm start the gps position ? i.e. connect the drone to a mobile phone, and send it the current position ?
TBS CROSSFIRE/ TRACER – MAVLink by WiFi
Ground control software like Mission Planner or APP QGroundControl
How it going Oscar I have a novice 4 that I enabled gps rescue to an aux switch now I can’t arm it in drop or land mode in the osd anymore? Before I assigned the switch I could arm in drop or land but couldn’t in gps ” I know because I didn’t have the required 6 sats” also the arm without fix was disabled from the factory all I wanted was gps rescue on an aux switch now I have lost the ability to arm in drop or land and even gps unless I get the minimum sats why is this happening? Also my 3d fix says false but
with this model all I was so supposed to be able to do was enable gps rescue which was done factory already and just assign my aux switch and that’s it but now I’m having these issues unless I turn off take off without a fix Thanks man I would love to hear back for this issue
If you enable “warning” in OSD element, that should tell you why it’s not arming on the screen?
If that doesn’t say it, you can follow my troubleshooting guide to find out why it’s not arming.
What is low throttle delay
Hi Oscar, Ive set up GPS rescue on my Iflight XL5 Quad HD. Im having issues my GPS Rescue. When I activate via an Aux switch to test it, the quad does not fly towards where it took off from. For what ever reason it always seems to fly off in the same direction no matter how many sats I have. In BF I have it set to a Minimum of 8 sats. The GPS unit has a compass and I have that connected, activated and calibrated. It seems that home point is never correctly set when I take off… Im at a loss as to what could be the issue. The GPS unit sits off the back of the quad underneath the DJI antennas. I’m running crossfire and that antenna is below and behind GPS unit. Do you think these could be causing some sort of issue?? Appreciate your thoughts. Cheers Matt
Have you tried disconnecting the compass in Betaflight (and the wires)? It should work without compass.
Also get the GPS co-ordinate of your home position from the OSD, and check it in google map see if the location is correct?
Hi Oscar. I tested failsafe by switching off my radio while the copter was about 5 meters in the air. I noticed that there was about a 1 second pause between when the motors stopped spinning and the GPS rescue kicked in, causing the copter to fall a few meters towards the ground before rising up again. How can I set it up so that the instant the signal is lost the GPS rescue will activate before the motors stop spinning?
My stage 2 guard time was set to 0.4 seconds by default, and throttle fallback was set to Auto.
Would setting the stage 2 guard time to 1 second, or setting throttle fallback to set = 1500 prevent this motor pause at signal loss?
Thanks
Steve
Can you try the following:
assign a Aux channel to rescue mode.
in Failsafe tab, Channel fallback settings, set that channel value to activate Rescue mode.
When Failsafe kicks in, Rescue mode should be activated immediately.
This is really useful. I tested my set up today, on a switch, and everything worked except regaining control.
It came back to me then hovered up and down in front of me. I could not regain control at all.
Reading more into it, I think it may be down to stick deflection. The default is set to 30% which means you need to move a stick more than 30% to regain control.
But flicking the switch out of rescue mode did nothing… would that be the same reason? Because in essence it’s locked in rescue mode until I move a stick more than 30%?
Same for me. You have to move the stick to regain control. I don’t understand, why this is not mentioned at all in Oscars article above!? Can you please comment @Oscar
This feature was introduced in Betalight 4.2 whereas I think this article and wiki it was based off at the time were referencing 4.1 where it was not a feature and it was instead recommended to manually switch GPS rescue mode via switch following failsafe. This is no longer required in 4.2 onwards with this new feature (called failsafe_stick_deflection in cli).
Hi Oscar, thanks for the helpful guides, I conformal coated my kakute f7 forgetting about the barometer, my altimeter now gives weird readings, if I setup gps rescue and the board will it have an effect?
You can disable Barometer in the “Configuration” tab, then altitude will be calculated from GPS data instead.
The blue light on the gps flashes, but the gps isn’t activated on the beta light, do you know why?
Hey oscar! Thanks for the step by step instructions. My drone’s gps rescue mode works perfectly but now i don’t know what happened. When i activate the gps rescue through a switch, the drone stumbles/stalls while turning. I did another test but this time the drone was already facing the home direction and when gps rescue activated, the drone Ascended and flew back home perfectly. May i know what causes the stall during yaw/turning?
Just the way it is right now, it has no way of knowing which direction it’s facing as it’s not using a compass, it can only work it out by flying forward and work it out that way that’s why it’s constantly adjusting its course.
Hey Oscar, I just wanted to say thankyou for all your different how to pages ,, I dont know anyone else who flys ,, your pages helped me with alot of different issues
Hello,
I believe I have my Gps rescue set up, it locks on to the satellite’s, but in BF the modes page….I don’t get the gps rescue tab turning yellow when I activate the switch, the marker goes into the yellow range on the slider but the GPS Rescue tab on the left does not turn yellow.I did test the switch in the air 150 meters away, and the quad tumbled from the sky and I lost video as soon as switch flipped? [email protected]
Put “Flight Mode” in your OSD, in Rescue mode it should change from “Acro” to “Resc”.
Something else I found with beta flight. So instead on the Failsafe tab you can set the value of a switch so that it’s in the active mode. So setting RTH switch to 1800 will have it activate that if it comes within range but forgot to turn on the switch
I tried setting set gps_rescue_min_sats = 0 in betaflight 4.2 and the entry is invalid. The lowest you can put seems to be 5
if you want to take off without GPS fix, just do this in CLI:
set gps_rescue_allow_arming_without_fix = ON
Great information Oscar,
I already set up rescue mode in betaflight and assign 1 switch on my TX for rescue mode,
Should I set in failsafe in my transmitter as well?
in my TX there is Failsafe mode = not set / hold / custom / no pulses, last time I use custom set (position to arm, level, rescue mode) but it disarm after failsafe 2 seconds, should I just set it to NO PULSE?
Yes, although failsafe always gets triggered first in Betaflight and that’s all you need, just set it to No Pulse in your radio anyway.
Hi Oscar,
So I lost video, hit the switch for Rescue but wasn’t sure so hit throttle anyway, I fly in Acro always, and I did manage to get the quad back but noticed on the HD footage it was fighting my throttle inputs and possibly stick bumps. Curious if that somehow ruins the FC or it just keeps fighting my stick inputs and prolongs my return?
Hey Oscar I installed RDQ mini 8 gps on kakute f7 and when I set a switch and checked in modes tab gps rescue doesnt highlight when switched on. I know in flight it has to be 100 meters away but when testing on the bench I think the mode should highlight like all other switched modes. Any idea what’s going on?
Hi Oscar. I have set up gps rescue on my quad with the matek 405 std flight controller and all seems to be working well thanks to your great instructions. My only concern is, and bear in mind I have only tested this with the props off on a bench, I have assigned rescue mode to a spare switch on the radio, and when I flick it, sure enough, rescue shows on the goggles screen, my worry is that when I arm the quad on the bench near the window, if I then press the rescue mode switch, it cuts the quads motors, is this just because it hasn’t taken off and gone anywhere yet. Many thanks. Ian.
you are too close, it has to be at least certain distance from the launch location (set in the CLI commands)
hi oscar, thank you very mutch for the description. it works fine.
for eachine x220hv @4s it is very important to change the default values form this parameter to:
gps_rescue_throttle_hover = 1400
gps_rescue_throttle_min = 1250
otherwise the drone fly back in rescue-mode like a frog. the motor seams to stopp every second an then start again and so on. this because the default value (1280) is to low for hovering. also the …trotte_min ist too low. you have to determine this paramter for your own drone.
Great write-up Oscar! Thank you. I set mine up but when it reached 100m from home it shut-off motors and crashed. :( Any suggestions?
because you set distance to 100m? you should just take over control as soon as you have signal, it’s not designed to return to home like DJI drones.
Hi Oscar,
Bravo !!! This blog is great,
Pls Help I’m still confuse and had a question when GPS rescue set with the fail safe logic not using switch as per below,
set failsafe_procedure = GPS-RESCUE
save
I know it will happen “automatically” during e.g rx loss…, and after the rx signal back to normal what will happen with fail safe procedure? can I control back my quad or let it land? under authority of failsafe?
You will regain control as soon as signal is back. Please read the section “Using GPS_Rescue for Failsafe” again, it tells you how it works and how it should be setup.
I ask you a question, does the GPS on the drone help stabilize it, kind of like dji that when they are with connected satellites are stuck in a place?
I believe gps rescue only helps you get back your quad not stabilise it at least in betaflight
Te hago una consulta el gps en el dron lo ayuda a estabilizarlo, tipo casi como los dji que cuando estan con suficientes satelites conectados se quedan clavado en un lugar ?
Oscar question how would I have gps rescue on a switch and also have my Fail-Safe set to either work like normal no gps rescue and have gps rescue activate when wanted on the same switch? Just in case I have rx loss in a bad area I don’t want it to activate GPS rescue like a bando spot or low clearance area…so I wanna have the betaflight Fail-Safe to be setup with a switch but have two options for Fail-Safe on a switch and a sepy switch for gps rescue all by itself? Is this possible?
Hi Oscar,
Many thanks for sharing this…. Test the GPS rescue with switch and works great.
Pls advice which failsafe mode i should choose in TX? I am using Tarani Xlite with r9 lite module. Should i just put “no pulse” or make it “Custom” and than set to activate GPS Rescue switch.
Thanks before
it shouldn’t matter as long as you use SBUS or FPort, because it has a failsafe flag in the protocol to notify the FC, but setting it to no pulse is probably the safest.
This looks great, thanks for the report. I lost video above a river last weekend and almost lost the quad… Luckily video came back.
However, I am running a full KISS (V1) setup. Is it possible to setup such a system on a KISS quad?
Not unless KISS support GPS. You’d have to check with KISS customer service, I am not sure if this is possible.
Hello Oscar!
How i need to set my failsave in crossfire, should i set it to cut, and in betaflight to gps rescue? is this ok? i use betaflight 4.0, and rth on a switch works perfect.
Thanks for Help!
Yea sounds good to me.
To add some feedback, in case it helps others: Adjust `gps_rescue_angle` with caution!
The default GPS Rescue Mode variables tested correctly on my 7″ SuperG+ running Betaflight 3.5.7. I sometimes fly during moderate wind where 32 degrees of pitch is insufficient, so I increased `set gps_rescue_angle` from 32 to 40 degrees. During testing, however, gps_rescue_angle=40 consistently caused the quad to reach altitude, then descend towards 0 altitude as it headed towards home (well before reaching `gps_rescue_descent_distance`). The quad would have crashed into the ground had I not taken control. I tried 4S, 5S, and 6S batteries with the same results. Increasing `gps_rescue_throttle_max` from 1600 to 1800 did not help. This is odd, as the quad is well tuned and I have no problem maintaining altitude when flying at a 40+ degree pitch.
All is well with gps_rescue_angle=32. Hopefully it’s not too windy when I need a rescue!
@jerrod I have gps mode enabled. I know this because I can see my long and lat on my OSD. I can see how many gps satalights im locked into.
But when I go into modes there is no rescue mode. It’s as if my version doesn’t support it but I’m using 3.5.6 and every guide says 3.5+.
@Tdub – in your config tab you have to enable GPS mode. Almost exactly half way down the page, on the right column.
@Oscar – I think you might have it backwards. My gps return to home works the other way – up arrow is toward home, down arrow means you’re traveling away from home.
Thanks for the article Oscar!
That’s what i mean exactly.
I’ve set up a GPS module via an open port. I have it communicating, I can see my GPS stats on my OSD but when I go into “modes” I do not have a “GPS Rescue” option. I have “Beep GPS Satellite Count” but no rescue mode. How do I enable that mode?
Hi, I set my Cl Racing F4S board and HGLRC Neo-8M GPS up exactly the way you wrote. I made a simple flight
in the front yard. The quad was only about 5 feet off the ground and flew out about 35 feet, stopped, turned around but all of a sudden it went full throttle and shot up only to either I killed the motors or the motors quit and it fell to the pavement nose first. (miraculously there was no damage except the ice that it hit) I have no idea what caused that to happen.
Now when I got the quad in the air again I didn’t touch Rescue or anything and as the quad was hovering in front of me the motors suddenly quit and it fell to the ground. I was informed that maybe the quad is going into failsafe mode. The board is new as is the Rx, was a clean build and everything is working.
I now understand that Rescue if activated closer than 100m will kill the motors but what happens if you are coming back on Rescue will it kill the motors when it comes within the 100m?
https://www.youtube.com/watch?v=BWmHsctdpck&t=1s
Thank you, your information is very valuable to us.
Jim
Hi Oscar (or anyone else, that can help) Ive type in get gps in the cli and I dont have set gps_rescue_min_dth = 100. If I try to add it in it comes back with ###ERROR### Invalid name. Is there a clever way of adding this command into the B/F 3.5.1 thats on my G730L please? Im stumped :(
This command is for the future version of Betaflight 4.0 (still in Beta).
For current stable Betaflight 3.5.X, use this command instead:
set gps_rescue_min_descent_dist = 100
I have tried both commands and am getting the invalid name on both. I have betaflight 3.5.6 installed. Any other recommendations?
can you try “get gps_rescue_” and try find it?
Hi Oscar, one question to ask ,
If I set failsafe on my transmitter for quad to power down the motors and drop , and I was to set up gps RTH as failsafe also ,
Question, what failsafe will the quad take orders from ?
Will it drop or RTH?
Thank you Oscar I’m learning a lot for your blog
Very new to the hobby
look at these as layers… TX, RX and FC, these are all layers.
The closest layer to your motors is the FC, so the quad will react to the FC failsafe layer first.
This is assuming you are using SBUS or CRSF, where the RX will send a “Failsafe flag” to the FC.
home arrow in Betaflight OSD says wrong direction and when turn on rescue going away from me——-why
not enough satellites? Or GPS module is interfered by VTX? Try further separation.
Hello Oscar! I have a question and think may know now but want to MAKE SURE…For the first trial with the rescue mode has me puzzled but I think that may be clear now as well…. Okay first time I tried it, it seemed to start to work, it went straight up I guess the the altitude have set but then dropped from the sky?! Now I think that is prob due to I turned GPS Rescue back off then tried to turn it back on, and after reading your article that seems to make it drop??…I think? as well as I “may” have disarmed it and rearmed it to try to get the “failsafe” rescue to kick in and prob re-set the “home” location?! Alright I am about to try it again now after doing some adjusting, BUT MY BIG question is “Which way should the arrow point for home” down?? For if I remember correctly I did watch someones video on this after my failure, and I believe and PLEASE TELL ME, when arrow is pointing downward is that pointing to “home” for I just flew it and seems that was direction it was when I was some distance away, and in the video I watched I DID notice that when rescue is activated the arrow JUMPS STRAIGHT UP on it’s return, so I still am confused?!! So which way should the arrow be pointing when I have it away from me and should be pointing “home”?? PLEASE let me know for need to test it again, but I almost lost it the first time just got lucky finding it somewhat. Thanks I greatly appreciate it!
If the arrow points up in OSD, means it’s flying away from home. If it points down, it means the quad is facing home.
please could you help I have put gps on my quad tested it in my garden with props off so got 8 sats come up when I flicked the switch the motors go very fast ,my question is why should it do this when it is not 100 m away ,should it have gone into failsafe and cut the motors ,I have set all the cli commands as you have and am running 3.5.1
Hi Oscar, would you know why I can get Rescue mode to work faultlessly when I activate it with a switch but when I try to activate it with failsafe either with Failsafe set to a switch or by turning off the transmitter it just disarms.
Rescue mode only works when the quad is further than 100m away (or any distance you set), within this distance you quad will just drop/disarm.
If this is not the case then you need to play with Insanity-Check’s options.
When testing GPS Rescue, make sure you land and disarm between tests. This is because the rescue altitude is set to the highest altitude you reach during flight or the minimum setting number (whichever is greater, ie. the quad will never descend when rescue is activated, it will only ascend or maintain altitude). If you do multiple rescue tests without disarming, then the minimum altitude can stack higher and higher depending on how high you are flying and each test the quad will climb a little bit higher due to the altitude error stacking.
Thanks for explaination!
What will drone doing when he returns to home, will it land automatically and disarm? For example if i have problems with radio.
No, it will not land but drop. Make sure to regain control.
Does anyone know whether this is possible using a FRSky GPS module? I have a feeling it’s not, and that the FrSKy only connects to the FrSky receiver not directly to the flight controller.
Hello Oscar. Thank you for the wonderful post.
Hi Oscar. Thank you so so much for this information. I have a question based on the last section of your blog. If I set Gps rescue to failsafe and I experience failsafe and lose video at the same time. My quad starts heading back and it reconnects to my quad, but I am flying blind. U said set the switch to failsafe as well. How do I set both up, failsafe and switch if I can only chose one mode. Please advice. Thank you. I have learnt a lot.
Setup GPS Rescue mode on a switch, so when failsafe happens, you should also flip the GPS Rescue mode switch.
Good information Oscar. I installed mine a couple of weeks ago (mini ublox M8N) strictly for lost quad location. I went out to check it out but due to a FC malfunction my quad went wildly out of control before i had a chance to ‘test’ the install. Long story short, got my GPS coordinates from my DVR, plugged them into my smartphone and it got me within 50 feet of my quad. :) With out the GPS i probably would have been hours trying to find the quad.
that’s good to hear bro!
I have experience the “drone falling out of the sky” issue. My question is: Why would sanity check make the quad behave properly when it doesn’t do that by arming through a switch. Have you test that? I have sanity check off because of this reason as of right now.
it’s really a hit and miss issue at the moment with Sanity Check. Make sure you understand the risk of turning it off. Sometimes it’s better to lose your quad than damaging something or someone more important.
Hi Oscar ! there’s one important detail in:
set gps_rescue_initial_alt = 50
where 50 is Alt in meters. this value means Absolute alt or above takeoff ?
because in my place Absolute hight ( ground level ) is about 180 meters so if I write 50 meters my drone becomes a suicide machine )))
It’s the height from ground :) so setting that to 50 would be 230m in your cause
Hi Oscar,
non-failsafe scenario question:
is it possible to take back the control if the mode was activated previously w. a switch?
If I turn the mode off w. the switch within the minimum range (before the quad “lands”) it falls from the sky.
BF3.4
thanks,
WP
Yea if it was activated with a switch, you can put it back in acro mode anytime using that switch. What’s your Sanity setting?
Thanks for this post! My next build will probably be a 6inch for mid/long range with gps, so this tutorial it’s perfect
When I first tested this (less than descent distance) it just disarmed in flight.Does any modification beed to be made to the sanity checks tonprevent this?
You can try
set gps_rescue_sanity_checks = RESCUE_SANITY_FS_ONLY
or even OFF, but that’s not recommended according to the wiki.
You need to be beyond the minimum range of 100m, maybe its set as part of descent distance, not sure on that. The disarm I believe is a safety measure so the drone doesn’t fly autopilot straight into you being so close to its home coordinates. Personally I would like to see a safety check added that if it is activated by switch within the 100m range, it simply does nothing but beeps an alarm onscreen “proximity” or something instead of dropping out of the sky.