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Betaflight GPS Rescue mode is much like “Return to House” on a DJI drone. This function is designed to fly your FPV drone again to its launch level and land it mechanically in a failsafe or when your video feed will get sketchy. On this tutorial, I’m going to stroll you thru establishing GPS Rescue Mode, testing it, and I’ll additionally share some tips about enhancing its efficiency and troubleshooting widespread points.
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Why GPS Rescue is a Recreation-Changer
Betaflight’s default failsafe motion is dropping the quad to the bottom. Now, with the newest GPS Rescue Mode, your drone can return near its launch level and land by itself! That is extremely helpful for long-range flights. Truthfully, I’ve misplaced depend of what number of instances GPS Rescue has saved my drones.
Selecting the Proper GPS Module
Prime Performer – HGLRC M100 Mini
Smallest Price Having GPS – GOKU GM10 Nano V3
Choosing a smaller GPS module helps save weight, but it surely does imply you’ll sacrifice a little bit of sensitivity that comes with fashions with a big antenna.
I even have good expertise with the BN-220 (on common over 20 satellites inside a few minutes). But, it’s outfitted with the older M8 chip, that means it usually takes longer to lock on to satellites in comparison with the newer M10 chips. If you’re struggling to get respectable efficiency with this GPS, you possibly can strive optimizing the settings as proven right here.
Get the BN-220 right here:
If you happen to’re eager about a GPS module with an onboard compass, Flywoo has choices, though it’s not essential for Betaflight’s GPS Rescue mode to work. The modules listed above ought to suffice for Betaflight customers.
Get the BN880 right here:
Era of GPS Chip
Most GPS modules for FPV drones use both an M8 or M10 chip. M10 chips are newer and supply higher efficiency, able to connecting concurrently to 4 International GNSS methods (GPS, Galileo, Glonass, and Beidou). This leads to quicker lock-ons and connections to extra satellites, particularly in areas with interference or restricted sky view. Regardless of their superior efficiency, M10 items aren’t rather more costly than M8 items, making them an economical improve.
Antenna Scratches
Seen scratches in your GPS antenna’s metallic patch? Don’t fear; this isn’t essentially an indication of defect or injury. It’s typically the results of manufacturing facility tuning to make sure optimum frequency. A lot of these antenna have a nominal tuned frequency, however are sometimes impacted by development, parts location and soldering. Inserting small nicks within the centre of the lengthy edges, or corners, can high quality tune its frequency.
Is a Barometer Wanted?
A barometer measures altitude utilizing air strain, and whereas many flight controllers include one built-in, e.g. the BMP280 (such because the Speedybee F405 V4 and RushFPV F722 V2), it’s not a should for GPS Rescue mode. Nonetheless, having a barometer can enhance altitude management. Simply bear in mind, should you’re making use of conformal coating for water resistance, keep away from protecting the barometer.
Some GPS modules supply a built-in barometer for an additional price. In case your flight controller doesn’t have one, including a module with a barometer may very well be useful.
Is a Compass Needed?
A compass (as often known as magnetometer in Betaflight) is for figuring out instructions.
Some GPS modules supply built-in compass, which may be related to the FC through the i2c port (SCL and SDA). Nonetheless, Betaflight Rescue Mode doesn’t require a compass to work, it may possibly work out its course from GPS information.
The truth is, an improperly calibrated compass would possibly trigger extra points than it solves. In my assessments, Rescue mode labored completely high quality with out a compass.
inform if a GPS module has built-in compass? If it has 6 wires or solder pads, it means it has a compass – 5V and GND for energy, TX and RX is for the GPS, and SCL and SDA (i2c port) are for the compass. If it doesn’t have a compass, then there ought to solely be 4 wires/pads – 5V, GND, TX and RX.
Connecting GPS to Flight Controller
Wiring a GPS module to the flight controller is sort of easy. Merely join it on to any out there UART on the FC, (TX to RX, RX to TX), and energy it with 5V.
- GPS RX – FC TX
- GPS TX – FC RX
- GPS 5V – FC 5V
- GPS GND – FC GND
- GPS SDA – FC SDA (if GPS has a compass/barometer)
- GPS SCL – FC SCL (if GPS has a compass/barometer)
Keep away from utilizing Softserial on your GPS connection, because it’s restricted to a 19200 baud charge. At 9600 baud, GPS reliability for Rescue Mode is compromised. A {hardware} serial port is your only option for a secure and dependable connection.
Some flight controllers, just like the Speedybee F405, function 4V5 pads. These are basically the identical as 5V pads however have the additional advantage of drawing energy from USB. That is significantly useful for these instances when the GPS is taking some time looking for satellites. By utilizing the USB for energy, you keep away from the chance of your VTX overheating whereas ready on the bottom with a LiPo battery plugged in. It additionally helps the GPS lock quicker because the VTX isn’t transmitting and inflicting interference. Word that some FCs would possibly supply 5V pads powered by USB however beneath completely different labels; test with a multimeter if uncertain.
Setup GPS in Betaflight
GPS Rescue mode in Betaflight is repeatedly evolving, so it’s essential to make use of the newest firmware model for brand new options and bug fixes. I like to recommend upgrading to Betaflight v4.5 for this course of: https://oscarliang.com/betaflight-4-5/
First, within the Configuration tab of the Betaflight Configurator, activate GPS for navigation and telemetry beneath the Different Options part. If GPS at all times deactivates after a reboot, it is perhaps attributable to not choosing GPS within the Cloud Construct choices throughout firmware flashing.
Subsequent, within the Ports tab, assign GPS to the suitable UART beneath “Sensor Enter.” Betaflight helps varied baud charges: 9600, 19200, 38400, 57600, 115200. If you’re uncertain what baudrate your GPS module helps, choosing AUTO normally works. If not, 57600 or 115200 are widespread charges in GPS modules.
Within the GPS tab, do the next:
- Choose UBLOX because the Protocol, which is the usual for many GPS.
- Allow Auto Config.
- Allow Use Galileo – it improves positioning accuracy.
- Allow Set House Level As soon as to forestall resetting the house location with every arm/disarm cycle till you unplug the battery.
- Select Auto-detect for Floor Help Sort to reinforce positioning accuracy.
- Save and Reboot.
After establishing, the GPS indicator on the prime of the configurator ought to mild up, indicating communication with the FC. A purple icon means GPS is speaking to the FC however with out a lock, and a yellow icon signifies a profitable GPS lock.
If the GPS indicator stays off, test for
- GPS is just not powered? Strive plugging in battery?
- Incorrect parameters, as an illustration, mistaken baud charge or protocol.
- Incorrect wiring, strive swapping TX and RX.
test if GPS is working?
Questioning in case your GPS module is speaking to the flight controller? The ‘gpspassthrough’ command within the CLI can reveal any ongoing information trade. Seeing a stream of binary information means communication is going on.
Run the ‘gpspassthrough‘ command within the CLI can reveal any ongoing information trade between the FC and GPS.
Seeing a stream of hieroglyphic binary information characters means communication is going on. If you happen to see nothing, there could also be a difficulty with energy, UART connection, or your setup.
Ready for GPS Lock
Getting a GPS lock, or “3D repair,” requires locking onto a minimum of 4 satellites and may take a couple of minutes.
While you energy up the GPS module for the primary time in a brand new location, it at all times takes longer to seek for satellites, often known as a “chilly begin”. Subsequent begins are usually faster because the module remembers satellite tv for pc positions (for instance whenever you change battery).
It’s tougher to get a lock indoor. If you must take a look at this inside the home, attempt to get near the home windows with the antenna pointing to the sky.
You will notice GPS associated info beneath the GPS tab, the place it exhibits the standing of your lock, your GPS coordinates and site on a map, verifying the accuracy of your GPS lock.
LED Indicators
On most GPS such because the BN220, BN180 and BN880, there are two LED indicators, labelled “TX” (normally blue) and “PPS” (normally purple).
Flashing blue (TX) signifies UART connection. Whether it is off, then the GPS is just not sending information out. That is additionally an indicator of the refresh charge, in 1Hz it ought to flash as soon as per second, whereas in 5Hz it’s going to flash 5 instances a second.
Flashing purple (PPS) signifies the 2D/3D repair standing of the GPS. If “PPS” is off you then don’t have a repair but.
When it will get a 3D repair, the purple LED on the BN-220 module ought to blink (along with the blue LED).
OSD
You may show GPS information within the OSD. Try this tutorial about Betaflight OSD if you’re not conversant in it. You may show GPS coordinates, distance and course to residence and extra.
To know what number of satellite tv for pc have been acquired, place the gps sats ingredient in your OSD. 6-8 is the minimal for rescue mode to work, the extra the higher. Your GPS coordinates can even get extra correct whenever you purchase extra satellites.
You may also show HDOP subsequent to the variety of satellites. HDOP is a measurement of the well being of the GPS locks. A HDOP worth of 1 or under is good, which might provide you with an accuracy of about 2.5 meters or much less. It is perhaps oversimplying, however simply consider it as how a lot the drone can be drifting horizontally in meters.
To do that, go to the CLI, and enter:
set osd_gps_sats_show_hdop = on
save
Radio Telemetry
Upon getting GPS setup and acquired a lock, go to the radio’s telemetry web page, choose “Uncover new sensors”. Some GPS associated new sensors ought to seem together with GPS coordinates. This solely works in case your radio system helps Telemetry – reminiscent of ExpressLRS and Crossfire.
This lets you log GPS coordinates in your radio, it means that you can hold observe of the final identified place of your plane. This may be useful for looking for the misplaced quadcopter should you can’t see the coordinates in your DVR.
Testing Angle Mode
Betaflight’s GPS Rescue mode depends on Angle mode — a self-leveling flight mode — to stabilize the drone. Due to this fact, it’s important to make sure Angle mode is functioning accurately.
First, confirm that the Accelerometer is enabled within the Configuration tab.
Subsequent, proceed to the Setup tab and calibrate the Accelerometer on a degree floor. Failure to take action would possibly consequence within the drone drifting whereas in Angle mode.
To check Angle mode, strive hovering the drone to see if it’s self-levelling as anticipated. Bear in mind, Angle mode makes use of solely the Accelerometer and Gyro, so it received’t hold the drone completely stationary like a DJI drone would. A slight drift attributable to weight distribution and wind is regular, so long as the drone stays secure. If drifting is noticeable, you possibly can trim the accelerometer within the Configuration tab to attenuate it (however unlikely to utterly remove it so don’t fear).
Additionally, pay attention to the throttle place throughout hover. This worth shall be helpful when establishing Rescue mode later.
Enabling GPS Rescue Mode in Failsafe
Navigate to the Failsafe tab within the Betaflight Configurator. If you happen to can’t discover this tab, be sure you’ve enabled the “Skilled Mode” choice on the prime of the display screen (subsequent to the Replace Firmware button).
Beneath Stage 2, choose GPS Rescue. Now, in case your drone enters failsafe, it’s going to set off GPS Rescue Mode.
So, what precisely is failsafe, and what are stage 1 and stage 2? Right here’s a fast rundown: Your drone enters failsafe upon shedding radio sign. By default, it could simply drop to the bottom, however with Rescue Mode, it’s going to try to return residence.
Throughout a failsafe, your drone will first enter Stage 1, pausing briefly (guard time) to see if the sign returns. If not, it progresses to Stage 2, activating Rescue mode to carry the quad again.
Whereas setting GPS Rescue as your failsafe technique is helpful, it’s not fitted to all environments. As an example, it’s not advisable in bando, forests, stadiums, or indoors. Shedding management beneath a tree or inside a constructing might consequence within the drone crashing into obstacles when Rescue mode engages.
In case you have no GPS lock when it failsafes, the quad will (ought to) simply drop to the bottom.
What Occurs after Rescue Mode is Activated?
Watch GPS Rescue Mode in motion right here:
Rescue mode includes 5 phases:
- Ascend: The drone climbs to a predetermined altitude or the utmost altitude reached throughout that flight.
- Rotate: It turns in the direction of the house course.
- Fly House: The drone begins its journey again to the launch level. The flight may not be a easy cruise, exhibiting some lateral actions because it navigates residence, however it’s going to finally arrive.
- Descend: As soon as close to the launch level, inside a 5x5m space, it begins descending slowly. The descent is perhaps uneven, with the motors making pulsating sounds because the drone tries to decelerate.
- Land: Upon touching the bottom, the drone mechanically disarms, with motors terminating primarily based on influence, not primarily based on altitude.
Cease Rescue Mode
If Rescue mode was activated through a change, regaining full management is so simple as disengaging that change.
If activated by failsafe:
- If it’s an actual failsafe triggered by a loss radio hyperlink, the pilot should transfer the sticks greater than 30% to regain management after radio hyperlink comes again.
- If the failsafe was triggered manually through a change, merely disengage the failsafe change — no have to wiggle the sticks.
GPS Rescue Settings
Settings for GPS Rescue mode can be found within the Failsafe tab.
You need to tweak the settings in Betaflight to make it work on your specific setup and surroundings. Be sure to take a look at the Betaflight wiki to totally perceive what the parameters do: https://github.com/betaflight/betaflight/pull/11579). The default is a fairly good start line, which is designed primarily for five″ freestyle drones.
Right here I’ll undergo the settings and share with you what values I exploit on my 5″ freestyle drone and why.
All of the settings are additionally accessible In CLI, enter get gps_rescue and you’ll get a complete listing of GPS associated parameters. But it surely’s simpler to vary them within the GUI (in Failsafe tab).
Angle – That is the utmost angle the drone can tilt in levels. In robust wind, you would possibly want the next angle to attain the specified velocity. That is very true for smaller quads. Nonetheless if the angle is just too steep the drone would possibly battle to remain within the air so it additionally is determined by the facility of the quad. If you happen to set a giant angle you need to count on some overshoot.
If you’re undecided, simply strive the default worth and see the way it carry out in testing.
You might want to allow Accelerometer and must be calibrated/trimmed correctly for this to work precisely. In case your ACC is defective, rescue mode may not work accurately for you. Confirm by flying in Angle mode.
I simply go away it at default, 40, it really works effectively for my 5″.
Preliminary Altitude (meters) – at what minimal top the drone returns residence relative to the take off level. It ought to be excessive sufficient to keep away from bushes, buildings and energy traces. However not too excessive it takes a very long time and an excessive amount of battery to ascend. I elevated it to 50m as we acquired some tall bushes and hills right here.
Descend Distance (meters) – at what distance from residence our drone begins to descend. I go away it at default.
Minimal distance to residence (meters) – The minimal distance to residence when rescue mode is allowed. There’s a tough restrict in Betaflight 4.4, 20m with 2m altitude, you possibly can’t set it decrease than that.
I go away it at default, 30m.
Floor velocity (meters/second) – Word when coming into this worth in GUI, the unit is completely different than CLI (which is cm/s). That is the velocity at which the quad travels throughout Rescue. The default 5m/s is 18km/h which I discover too gradual, I doubled that to 10m/s which is 36km/h. The quad’s journey course can be extra correct and replace quicker in larger velocity (when a compass is just not used and the orientation derives from GPS). Don’t set it to decrease than 2m/s or orientation received’t work.
Throttle minimal, Throttle most, Throttle hover – these are the min, max and hover throttle values you need to use throughout Rescue mode. Set most so the quad isn’t too quick/jerky (it ought to be above your hover level), set min to maintain the props spinning at an inexpensive charge (it ought to be decrease than your hover level).
To set hover level, you might want to decide an correct worth. Take a look at your quad and see at precisely what throttle it hovers (simply sufficient throttle to maintain the quad afloat), actually each quad is completely different. Use the “Throttle %” OSD ingredient to get the precise worth as a substitute of simply guessing. In line with information within the pull request, “the right worth ought to trigger the quad to climb a bit whereas in degree mode… If these values are set too low, the quad will drop early within the rescue – presumably into the water!”.
Ascend charge, Descend charge (meters/second) – fairly self-explanatory. Modify these primarily based in your surroundings, climate situation and your quad’s energy. I usually simply go away it to default for my 5″ and it really works fairly effectively. If you happen to use Li-ion packs or low C-rating LiPo, perhaps use a decrease Ascend charge.
Minimal Satellites – Your quad received’t arm if the GPS has fewer satellites than this worth. The advisable variety of Sats is 8 for dependable rescue mode. 5 or 6 would possibly nonetheless work, however it is going to be sketchy. For me it solely takes a minute or two to get 10-20 satellites, so I simply go away it on the default, 8.
Word that should you take off earlier than the GPS attain the minimal quantity of satellites, it received’t know the place residence is strictly. Extra satellites means higher place accuracy, you possibly can scale back the variety of sats however the place accuracy will go down.
By enabling “Permit arming with out repair“, you possibly can nonetheless arm the quad when satellite tv for pc locks is under the “minimal Satellites” quantity. I normally allow this as a result of it’s extra versatile – I don’t have to attend round after I simply need some fast flights in my acquainted native park. However every time I’m flying in a brand new spot, over water or diving down cliffs, I at all times watch for satellite tv for pc lock.
Beware that GPS Rescue WILL NOT work for that flight should you arm earlier than getting a satellite tv for pc lock (as a result of it doesn’t know the house place).
In case you have bother getting these many sats (or it takes a very long time), take a look at my tutorial on how you can increase your GPS receiver efficiency. Get a brand new GPS should you should, they solely price $15, a fantastic funding for shielding your $300 quad!
Altitude Mode – it determines the altitude at which the quad returns residence.
- Most altitude is the very best altitude your quad is flown throughout that flight
- Fastened altitude is only a consumer outlined worth
- Present altitude is no matter top that the quad is at when GPS rescue mode is activated
The choice is determined by your surroundings. Most altitude might be the most secure choice in my view, but it surely’s not at all times the best choice say should you have been diving a mountain in that flight, you could possibly be losing vitality climbing again to the max altitude when Rescue mode is activated. Be adaptive to the completely different surroundings and missions.
Sanity Checks – when set to “ON”, it always screens GPS Rescue mode circumstances, for instance:
- is GPS nonetheless related
- are we getting good variety of satellite tv for pc repair
- are we a minimum of 100 meters away from residence? (distance may be modified)
- are we getting nearer to the house, and we didn’t hit an impediment
If any of those circumstances will not be met, it’s going to abort rescue mode and your quad will simply disarm and drop to the bottom. So yea, it’s not supreme if you’re flying over unrecoverable locations like ocean or mountains, however usually, it ought to be on for security causes.
The Betaflight wiki additionally recommends setting Sanity Checks to “Failsafe Solely” if you’re having bother with the choice “On” throughout testing. It turns Sanity Checks off when Rescue mode is activated by a change however solely turns it on when it’s in failsafe. That is additionally my most popular choice.
It’s extra dangerous to show off Sanity Examine totally, you would possibly get an indefinite flyaway. In Betaflight 4.4, there’s now a restrict of 20s of sanity failure even when all sanity checks are off. It’s a security factor. By no means fly with all sanity checks off.
Manually Activate GPS Rescue?
Aside from failsafe, you too can manually activate GPS Rescue by flipping a change in your radio transmitter. It’s helpful in emergency conditions like shedding orientation (e.g. when flying LOS) or your FPV system stops working, you will get the drone to fly again residence by itself.
Go to the Modes tab and add a AUX channel for GPS Rescue Mode. Unfamiliar with the Modes tab? See my tutorial right here: https://oscarliang.com/betaflight-modes/
Throttle Channel Fallback
Throughout the stage 1 of a failsafe, the drone will go into channel fallback, which implies every radio channel shall be set to particular values. You would possibly need to assessment these values for optimum security.
The default Channel Fallback setting for Throttle is “Auto”, which drops the throttle to zero when Stage 1 failsafe is activated. While you change Stage 2 failsafe from the default worth “Drop” to “GPS Rescue”, within the occasion of a failsafe the motors will momentarily cease for the Guard Time (1.5 seconds by default in BF4.4). This would possibly destabilize the quad whereas GPS Rescue kicks in, and Betaflight thinks there’s one thing mistaken because it fails one of many sanity checks and trigger the drone to only drop to the bottom.
A workaround can be to set the Throttle Channel Fallback setting from “Auto” to “Maintain”, so the throttle worth is held at its final commanded place for the Guard Time to keep away from the motor stalling.
Even higher, I usually set throttle to the hover throttle worth, middle all of the roll/pitch/yaw sticks, and put the quad in Angle mode, in order quickly as Failsafe occurs the quad simply ranges out and stays there till Rescue mode kick in (if my radio sign doesn’t come again).
By no means set throttle to zero in stage 1 failsafe!
Take a look at GPS Rescue
Right here’s how I might take a look at GPS Rescue.
To begin with, assign a change to GPS Rescue and ensure it may possibly certainly carry your quad residence as meant. If something goes mistaken, disengaging the change ought to provide you with full management once more.
Subsequent, assign a change to Failsafe within the Modes tab in Betaflight. It emulates full failsafe mode in Betaflight (similar to whenever you lose RC sign). This can be a lot safer than testing by turning off your radio, as a result of you possibly can disengage anytime you need utilizing a change.
Word that that is just for testing GPS Rescue mode, as quickly as you end testing, you need to take away it within the modes tab.
Take away all props, go into the Modes tab and confirm that Failsafe mode can really get activated by the change. At this level your quad will go into Rescue mode, and your radio controls shall be locked out. Now test should you can deactivate failsafe and take again management.
When you find yourself testing this on the bench, with the USB cable related, the Rescue mode field received’t flip yellow like different modes. That is high quality so long as the small yellow bar can transfer to the activation vary.
It’s helpful to have these GPS associated information in your OSD, they’ll aid you perceive what your quad is doing. You may also have Flight Mode enabled, it’ll say “RESC” when Rescue mode is activated, “Air” when your quad is in charge mode, and “Angle” when it’s in angle mode.
Now take a look at it in an open discipline with no obstacles and other people.
Ensure you have sufficient locked satellites within the OSD earlier than arming.
Fly in a straight line, 100-200 meters away.
Activate Failsafe mode utilizing the change, shortly your quad ought to enter GPS Rescue mode (watch the flight mode in OSD).
Take note of the house arrow in Betaflight OSD, if it’s pointing up, it means you might be flying residence. If it’s pointing down, means you might be flying away from residence. The arrow is perhaps pointing the mistaken course firstly, that is regular. Simply ensure that the quad isn’t flying the exact opposite course.
You may stop failsafe mode by flipping the change at any time and resume full management.
If you happen to don’t disengage, it’s going to keep it up flying residence. When the quad reaches residence, it’s going to hover for a bit and begins to slowly descend however the motors shall be pulsating… till it hits the bottom and disarms mechanically.
Repeat the process repeatedly till you’re feeling snug with it.
As soon as you might be completed with testing, take away Failsafe from the Modes tab.
Ideas
Greatest Locations to Mount GPS Module
Be sure the GPS eramic patch antenna has a transparent view of the sky for locking onto satellites, and nothing is protecting it which may weaken GPS sign, particularly conductive supplies reminiscent of carbon fibre, electrical wires, and steel.
Keep away from EMI from different electrical parts in your quad. Widespread RF interference sources that may influence GPS efficiency are HD digital camera and video transmitter. Mount your GPS as distant from these gadgets as potential.
One widespread mistake is mounting the GPS the wrong way up. The GPS receiver antenna ought to be dealing with up, it’s a flat sq. with small steel round half within the center. There ought to be no parts in any respect on this aspect. For example, that is the ceramic antenna in a GPS receiver, it ought to be dealing with up.
Be sure there’s nothing blocking or interfering with the GPS unit at anytime. Mount it on prime of your quad, as distant from the VTX / RX antennas as potential (many radio receivers can really transmit sign as effectively attributable to their two-way communication nature when telemetry is enabled). Additionally beware some HD cameras would possibly produce radiation that may have an effect on your GPS sign as effectively in the event that they don’t have the suitable shielding.
Listed below are some concepts the place/how you can mount the GPS module in an FPV drone.
On prime of your GoPro/HD digital camera.
On prime of your body in case you have an under-slung battery.
Utilizing a mast to maintain the GPS as distant from the quad as potential. However most likely a foul thought to have it so near the VTX antenna on this instance…
The rule of thumb is that the GPS should see the sky always (besides when you’re doing a roll or inverted yaw spin).
Earlier than your flight, it may possibly take some time to get a GPS lock. You would possibly need to energy in your quad and GPS beforehand to “heat up” first, e.g. on the best way to the flying discipline.
Get a GPS Lock Quicker
Most GPS modules have a small battery, which is used to retailer satellite tv for pc info and time for a quicker lock.
After the GPS module will get a satellite tv for pc lock, it remembers all of the satellite tv for pc places, so after you modify the drone’s battery (the GPS module is powered off briefly), the GPS lock normally can resume virtually instantly. However when the GPS doesn’t have satellite tv for pc info saved in reminiscence, or the satellites it remembers are not in view, it’s going to take for much longer to get a lock.
That is why some folks powered on their quad (or simply the GPS module) previous to their flight simply to get a lock, so that they don’t have to attend round earlier than taking off.
In case your GPS at all times takes a very long time to get a lock, it’s value checking if the battery is useless (with a multimeter). Additionally ensure that there’s as little interference to the GPS as potential, for instance if you’re using1.3GHz FPV setup, strive transferring highly effective VTX away from the GPS. Cloudy day can even impact GPS sign high quality.
Additionally take a look at my publish about optimizing GPS settings to get extra satellite tv for pc locks.
Phrases from Betaflight Devs
I like to recommend 10 satellites. [And] Await 30s after [you have] 10 satellites for altitude to stabilise [before taking off].
At all times affirm regular GPS Rescue behaviour at the beginning of a essential flight by testing with the failsafe change. Set the change to instantly enter Stage 2. You may enter and go away GPS Rescue through the change with speedy on and off impact. Examine that the quad rotates and flies in the direction of residence and does the best issues earlier than you might be so distant {that a} true failsafe could happen.
ALWAYS CHECK that the House Arrow factors straight again in the direction of residence after takeoff! Generally, should you take off and spin round throughout arming or instantly on takeoff, the quad’s perspective info can turn into corrupted, and the House Arrow can level the mistaken manner. It’s finest to arm cleanly and fly away from House in a straight line at an inexpensive velocity instantly after takeoff. Watch the House Arrow fastidiously to make sure it shortly factors again to House. If the House Arrow factors the mistaken manner when a failsafe happens, the GPS Rescue will initially fly off within the mistaken course, and in some circumstances, chances are you’ll lose the quad.
Improper course in Rescue?
With out a compass, your quad can nonetheless work out course utilizing GPS coordinates. By flying ahead the drone can calculate which manner it’s going by evaluating the present place and the earlier place. That’s why firstly, your quad is perhaps wandering round and even flying in the direction of the mistaken course however finally it ought to appropriate itself. In case your GPS sign is weak or updating too slowly it may possibly take longer to appropriate.
If you’re utilizing a compass and it’s flying the mistaken course, then perhaps there’s one thing mistaken with the compass, or perhaps it’s not calibrated correctly. On this case strive turning off the magnetometer (compass) and check out once more. If it really works now, it proves your compass is the supply of the issue.
In case your yaw is jerky throughout Rescue mode, your GPS is perhaps updating too slowly (e.g. 1Hz), attempt to improve it to 5Hz and even 10Hz following this information (solely works on sure GPS modules).
Keep away from Softserial
Keep away from utilizing Softserial for GPS, because it solely helps as much as 19200 baud charge, and with 9600 baudrate the GPS is just not dependable sufficient for GPS operations. It’s finest to make use of a {hardware} serial port (any TX and RX pins on the FC), and set baudrate to a minimum of 57600.
Not Getting GPS Lock
Interference from different electronics reminiscent of your VTX, radio receiver in case you have telemetry, and even close by wires that carry plenty of present can stop the GPS from getting a lock. In case you have bother getting a GPS lock, strive the next:
- Attempt to energy your FC from USB and see if that powers up your GPS module. If not, attempt to transfer your GPS module energy to a different pad on the FC that will get energy from the USB port
- Powering solely the FC with out the VTX ought to make it simpler for the GPS to get a lock, when you get a lock, it ought to keep locked usually even when the VTX is powered on. But it surely’s nonetheless a good suggestion to mount your GPS as distant from VTX antenna and RX antenna as potential
- Shielding close by wires can even assist typically. Wires carrying present are like antennas, they may additionally probably mess with GPS
GPS satellites transmit information on two frequencies, L1 1575.42MHz and 1227.60MHz, therefore 1.3GHz FPV could cause interference to your GPS. Most individuals run 5.8GHz so this shouldn’t be a difficulty. However since GPS sign is so weak (it’s all the best way from house in spite of everything), any highly effective sign close by could cause interference, due to this fact you need to mount the GPS module as distant from any transmitting sources as potential.
While you run your GPS wires to the FC beneath the VTX, it may possibly additionally trigger points as sure VTX’s don’t have correct RF shielding and the RF noise is sufficient to mess up your GPS. For instance the Avatar VTX is thought to trigger GPS situation when working wires beneath it. Options may very well be correctly grounding the VTX shielding, however you could possibly additionally attempt to protect the wires between the GPS and FC, and ensure to floor it.
I attempted shielding the wires with some foil in certainly one of my quads, then join the foil to a floor pad on the FC (to floor it). Lastly wrap it with some material tape so it doesn’t brief the body. Some folks reported good consequence with this modification, for me the advance is little, but it surely’s value a shot if there’s no different simple resolution.
Can’t allow GPS after flashing Betaflight
It’s potential that GPS was excluded from the compiled firmware as a result of new Cloud Construct system in Betaflight 4.4.
To substantiate that is the case, enter this command in CLI:
function gps
If CLI returns “gps not out there”, then it means the GPS function isn’t a part of the betaflight firmware in your FC. On this case you’ll have to reflash your FC, this time you need to ensure that GPS included in the Cloud construct system choice when compiling it.
GPS Coordinates Decimals
To show GPS coordinates within the OSD you’ve the choices to pick out what number of decimals to show (presently solely 4 and seven decimals can be found). It impacts how exact the place is whenever you seek for the coordinates on a map.
On Wikipedia web page “Decimal Levels” there’s a desk on Diploma Precision vs. Size.
decimal locations levels distance ------- ------- -------- 0 1 111 km 1 0.1 11.1 km 2 0.01 1.11 km 3 0.001 111 m 4 0.0001 11.1 m 5 0.00001 1.11 m 6 0.000001 11.1 cm 7 0.0000001 1.11 cm 8 0.00000001 1.11 mm
Watch out for the distinction between accuracy and precision. Your GPS could report any variety of digits (its precision) however lots of the decimal locations is perhaps simply inaccurate (accuracy)1.
Edit Historical past
- Oct 2018 – tutorial created
- Aug 2020 – up to date, GUI modifications, CLI parameter names modifications, added throttle min/max/hover values
- Feb 2023 – up to date for BF4.4 (with auto touchdown functionality)
- Mar 2024 – up to date for BF4.5