27K
Betaflight GPS Rescue mode is much like “Return to Dwelling” on a DJI drone. This characteristic is designed to fly your FPV drone again to its launch level and land it routinely 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.
A few of the hyperlinks on this web page are affiliate hyperlinks. I obtain a fee (at no further value to you) should you make a purchase order after clicking on considered one of these affiliate hyperlinks. This helps assist the free content material for the neighborhood on this web site. Please learn our Affiliate Hyperlink Coverage for extra info.
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. Actually, 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 Value 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 first rate efficiency with this GPS, you possibly can strive optimizing the settings as proven right here.
Get the BN-220 right here:
Should you’re enthusiastic about a GPS module with an onboard compass, Flywoo has choices, though it’s not needed for Betaflight’s GPS Rescue mode to work. The modules listed above ought to suffice for Betaflight customers.
Get the BN880 right here:
Technology 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 programs (GPS, Galileo, Glonass, and Beidou). This leads to sooner 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 unit tuning to make sure optimum frequency. These kinds of antenna have a nominal tuned frequency, however are sometimes impacted by development, elements location and soldering. Putting small nicks within the centre of the lengthy edges, or corners, can tremendous 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. Nevertheless, 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 value. In case your flight controller doesn’t have one, including a module with a barometer may very well be helpful.
Is a Compass Needed?
A compass (as referred to as magnetometer in Betaflight) is for figuring out instructions.
Some GPS modules supply built-in compass, which might be linked to the FC by way of the i2c port (SCL and SDA). Nevertheless, Betaflight Rescue Mode doesn’t require a compass to work, it may possibly work out its route from GPS information.
In truth, an improperly calibrated compass may trigger extra points than it solves. In my exams, Rescue mode labored completely tremendous with out a compass.
How you can 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 kind of simple. 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 price. At 9600 baud, GPS reliability for Rescue Mode is compromised. A {hardware} serial port is your best choice for a steady and dependable connection.
Some flight controllers, just like the Speedybee F405, characteristic 4V5 pads. These are basically the identical as 5V pads however have the additional benefit of drawing energy from USB. That is notably 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 sooner for the reason that VTX isn’t transmitting and inflicting interference. Notice that some FCs may supply 5V pads powered by USB however beneath completely different labels; examine with a multimeter if not sure.
How you can 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 spanking 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 may be on account of 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 not sure what baudrate your GPS module helps, choosing AUTO often 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 Dwelling 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 Kind to boost positioning accuracy.
- Save and Reboot.
After establishing, the GPS indicator on the prime of the configurator ought to gentle up, indicating communication with the FC. A pink 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, examine for
- GPS is just not powered? Strive plugging in battery?
- Incorrect parameters, as an example, improper baud price or protocol.
- Incorrect wiring, strive swapping TX and RX.
How you can examine 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 change. Seeing a stream of binary information means communication is going on.
Run the ‘gpspassthrough‘ command within the CLI can reveal any ongoing information change between the FC and GPS.
Seeing a stream of hieroglyphic binary information characters means communication is going on. Should you 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 at the very least 4 satellites and might take a couple of minutes.
Once 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, referred to as a “chilly begin”. Subsequent begins are usually faster because the module remembers satellite tv for pc positions (for instance once you change battery).
It’s more durable to get a lock indoor. If you must check this inside the home, attempt to get near the home windows with the antenna pointing to the sky.
You will note GPS associated info beneath the GPS tab, the place it exhibits the standing of your lock, your GPS coordinates and placement 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” (often blue) and “PPS” (often pink).
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 price, in 1Hz it ought to flash as soon as per second, whereas in 5Hz it would flash 5 instances a second.
Flashing pink (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 pink LED on the BN-220 module ought to blink (along with the blue LED).
OSD
You’ll be able to show GPS information within the OSD. Try this tutorial about Betaflight OSD if you’re not aware of it. You’ll be able to show GPS coordinates, distance and route to house and extra.
To know what number of satellite tv for pc have been acquired, place the gps sats factor in your OSD. 6-8 is the minimal for rescue mode to work, the extra the higher. Your GPS coordinates will even get extra correct once you purchase extra satellites.
It’s also possible to 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 beneath is right, which might provide you with an accuracy of about 2.5 meters or much less. It may be 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 obtained 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 – similar to ExpressLRS and Crossfire.
This lets you log GPS coordinates in your radio, it permits you to hold monitor of the final recognized 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. Subsequently, 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 stage floor. Failure to take action may 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 on account of weight distribution and wind is regular, so long as the drone stays steady. If drifting is noticeable, you possibly can trim the accelerometer within the Configuration tab to reduce it (however unlikely to fully eradicate it so don’t fear).
Additionally, be aware of 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. Should you can’t discover this tab, be sure you’ve enabled the “Professional Mode” choice on the prime of the display (subsequent to the Replace Firmware button).
Beneath Stage 2, choose GPS Rescue. Now, in case your drone enters failsafe, it would 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 might simply drop to the bottom, however with Rescue Mode, it would try to return house.
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 deliver the quad again.
Whereas setting GPS Rescue as your failsafe methodology is useful, it’s not fitted to all environments. For example, it’s not advisable in bando, forests, stadiums, or indoors. Dropping management beneath a tree or inside a constructing might consequence within the drone crashing into obstacles when Rescue mode engages.
You probably 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 entails 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 route.
- Fly Dwelling: The drone begins its journey again to the launch level. The flight may not be a clean cruise, exhibiting some lateral actions because it navigates house, however it would finally arrive.
- Descend: As soon as close to the launch level, inside a 5x5m space, it begins descending slowly. The descent may be uneven, with the motors making pulsating sounds because the drone tries to decelerate.
- Land: Upon touching the bottom, the drone routinely disarms, with motors terminating primarily based on influence, not primarily based on altitude.
How you can Cease Rescue Mode
If Rescue mode was activated by way of 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 by way of a change, merely disengage the failsafe change — no must wiggle the sticks.
GPS Rescue Settings Defined
Settings for GPS Rescue mode can be found within the Failsafe tab.
You must tweak the GPS Rescue settings in Betaflight to your particular setup and surroundings. I extremely advocate visiting the Betaflight wiki to know a full understanding of what every parameter entails: https://github.com/betaflight/betaflight/pull/11579. The default settings supply a stable place to begin, particularly for five″ freestyle drones.
Right here, I’ll stroll you thru the settings, sharing the values I take advantage of on my 5″ freestyle drone and the reasoning behind every alternative.
Accessing all settings is easy by way of CLI—simply enter get gps_rescue for a complete checklist of GPS-related parameters. Nevertheless, adjusting them within the GUI (Failsafe tab) tends to be extra user-friendly.
Altitude Mode: It determines the altitude at which the quad returns house.
- Most altitude is the very best altitude your quad is flown throughout that flight
- Mounted altitude is only a predefined worth
- Present altitude is no matter peak that the quad is at when GPS rescue mode is activated
Your best option varies with every flight’s context and surroundings. Most altitude is usually a protected choice, but it surely’s not at all times the best choice. For example, should you was diving a mountain in that flight, you would be losing vitality climbing again to the max altitude when Rescue mode is activated. Be adaptive to the completely different surroundings and missions.
Preliminary Climb (meters): The space the quad will climb, above the present altitude, when a rescue is initiated and the altitude mode is about to Present Altitude. Additionally added when in Max Altitude Mode.
Return Altitude (meters): Solely applies in Mounted Altitude mode. This determines the drone’s return altitude relative to its takeoff level. It must be excessive sufficient to clear any obstacles like timber and buildings however not so excessive that it excessively consumes battery throughout ascent. For my flying spots, which options tall timber and hills, I’ve bumped this as much as 50 meters.
Ascend/Descend Fee (meters/second): These charges rely in your surroundings, climate, and quad’s energy. For my 5″ setup, the defaults ought to work properly. If utilizing Li-ion packs or low C-rating LiPo, think about a decrease ascend price.
Return floor pace (meters/second): That is the pace 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 route can be extra correct and replace sooner in larger pace (within the absence of a compass). Don’t set it to decrease than 2m/s or orientation received’t work. Notice when coming into this worth in GUI, the unit is completely different than CLI (which is cm/s).
Most Pitch Angle: This setting caps the drone’s tilt angle. The next angle results in extra aggressive returns and better pace. Possibly helpful for heavier, excessive drag and low authority drones. In windy circumstances, a better angle may be needed for sustaining pace, particularly for smaller quads. Nevertheless, with an excessively steep angle the drone might lose altitude and crash. Not sure of what to set? Beginning with the default worth of 40 levels is a protected guess—it’s labored properly for my setup.
Descend Distance (meters): That is the distance from house our drone begins to descend. I stick to the default right here.
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 must be above your hover level), set min to maintain the props spinning at an inexpensive price (it must be decrease than your hover level). I left Throttle Min/Max at default.
To set Throttle Hover, it’s worthwhile to decide an correct worth. Check fly 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 factor 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 stage mode… If these values are set too low, the quad will drop early within the rescue – probably into the water!”.
Minimal Distance to Dwelling (meters): If Rescue begins too near house (inside this minimal distance), the drone will fly away on its present heading till this distance from house, and begin the conventional Rescue behaviour. I go away this on the default 15 meters.
Minimal Satellites: A minimal of 8 satellites ensures dependable Rescue mode operation. Should you take off earlier than the GPS attain the minimal quantity of satellites, it received’t know the precise house location. Extra satellites imply higher accuracy. I go away this on the default, 8.
Enable Arming With out Repair: This selection supplies flexibility by permitting arming with out a GPS lock. I allow this for the comfort of check flights, however make sure you get a GPS lock for once you intend to make use of GPS Rescue Mode.
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).
You probably have hassle getting these many sats (or it takes a very long time), try my tutorial on methods to enhance your GPS receiver efficiency. Get a brand new GPS should you should, they solely value $15, a fantastic funding for safeguarding your $300 quad!
Sanity Checks: When set to “ON”, it displays GPS Rescue mode circumstances, for instance:
- Is the GPS nonetheless linked to the FC?
- Are we getting a very good variety of satellite tv for pc locks?
- Are we at the very least 20 meters away from house?
- Are we getting nearer to the house, and we didn’t hit an impediment?
If any of those circumstances should not met, it would abort rescue mode and your quad will simply disarm and drop to the bottom. So yea, it’s not ideally suited if you’re flying over unrecoverable locations like ocean or mountains, however usually, it must be on for security causes.
The Betaflight wiki additionally recommends setting Sanity Checks to “Failsafe Solely” if you’re having hassle 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 well-liked choice.
It’s dangerous to show off Sanity Examine fully, you may get an indefinite flyaway. In Betaflight 4.4, there may be 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.
How you can Manually Activate GPS Rescue?
Moreover failsafe, you may have the choice to manually set off GPS Rescue by flipping a change in your radio transmitter. This characteristic is useful throughout emergencies, similar to shedding your method or encountering points together with your FPV system, permitting your drone to autonomously return house.
Go to the Modes tab in Betaflight Configurator and assign an AUX channel particularly for GPS Rescue Mode. Should you’re new to configuring modes, try my tutorial right here: https://oscarliang.com/betaflight-modes/
Throttle Channel Fallback
Throughout Stage 1 of a failsafe, your drone goes into channel fallback, that means every radio channel is about to predefined values. It’s smart to assessment these values to make sure security.
By default, the Channel Fallback for Throttle is about to “Auto,” which reduces the throttle to zero, leads to the motors stopping momentarily in the course of the guard time. This interruption might destabilize the drone earlier than GPS Rescue kicks in, doubtlessly failing a sanity examine and inflicting the drone to drop to the bottom.
One resolution is to regulate the Throttle Channel Fallback from “Auto” to “Maintain,” sustaining the final throttle worth all through the guard time, stopping motor stalling.
Nevertheless, I personally favor setting the throttle to the hover worth, in addition to centering all roll/pitch/yaw channels, and interesting Angle mode. This fashion, the quad ranges itself and doesn’t ascend or descend when failsafe occurs, earlier than GPS Rescue engages.
Bear in mind, by no means set throttle to zero throughout Stage 1 of failsafe!
How you can Check GPS Rescue
Testing GPS Rescue is a vital step earlier than counting on it in real-world eventualities. Right here’s my strategy to making sure it really works as anticipated.
The Setup
First, assign a change in your radio to GPS Rescue to substantiate it may possibly certainly deliver your drone house. Ought to something not go in accordance with plan, flicking the change off ought to instantly return management to you.
Subsequent, allocate one other change to Failsafe within the Modes tab. This simulates a full failsafe occasion, similar to shedding RC sign, however in a a lot safer method since you possibly can exit the mode at any time when needed utilizing the change. It’s vital to notice that this setup is strictly for testing functions. When you’re completed, bear in mind to take away Failsafe within the Modes tab.
With the propellers eliminated, head to the Modes tab and be certain that activating the Failsafe change certainly triggers Rescue mode, throughout which your radio sticks shall be momentarily locked out. Confirm should you can exit failsafe mode and regain management easily.
Whereas bench testing with a USB connection, the Rescue mode indicator may not illuminate as different flight modes do. Nevertheless, so long as the small yellow bar bar strikes into the activation zone, it’s working accurately.
Incorporating GPS-related info into your OSD is useful, offering insights into the drone’s standing. The Flight Mode indicator is especially useful, displaying “RESC” when in Rescue mode, “Air” in price mode, and “Angle” in angle mode.
Discipline Testing
For an precise check, select an open space free from obstacles and other people. Make sure the OSD exhibits a adequate variety of locked satellites earlier than arming.
Take off and fly in a straight line for 100-200 meters, then set off Failsafe mode utilizing the change. The quad ought to promptly change to GPS Rescue mode—observe this transition within the OSD’s flight mode show.
Take note of the house arrow within the OSD; when it’s pointing up, means you’re heading house, when pointing down means you’re flying away. Initially, the arrow may level within the improper route, which is regular because it takes just a few seconds for Betaflight to work out which route it’s heading—simply make sure the drone isn’t flying the exact opposite route.
You’ll be able to give up failsafe mode at any time by flipping the change, regaining full management instantly.
Should you select to not disengage, the drone will proceed flying again to the launch level. Upon arrival, it would hover briefly earlier than beginning a gradual descent, throughout which the motors could pulsate, till it safely lands and disarms routinely.
Repeat this course of just a few instances, till you’re assured within the system’s reliability. After thorough testing, don’t neglect to take away Failsafe from the Modes tab.
Suggestions and Troubleshooting
Greatest Locations to Mount GPS Module
Ensuring your GPS module’s ceramic patch antenna has an unobstructed view of the sky is essential for fast and dependable satellite tv for pc lock-on. Something protecting it, notably conductive supplies like carbon fiber, electrical wires, or metallic, can considerably weaken the GPS sign.
Avoiding EMI
Electromagnetic interference (EMI) from different electrical elements in your quad may also have an effect on GPS efficiency. Notable sources of RF interference embrace HD cameras and video transmitters. To mitigate this, mount your GPS as distant from these gadgets as potential.
Correct Mounting Orientation
A standard error is mounting the GPS the other way up. The receiver antenna, identifiable by its flat sq. form with a small metallic round half within the heart, ought to at all times face upwards. Guarantee no elements impede this aspect. Within the following picture for instance, the ceramic antenna is going through up.
Placement Methods
Ensure there’s nothing blocking the GPS unit always. Ultimate mounting spots embrace the highest of your quad, distant from VTX and RX antennas, and away from potential radiation sources like HD cameras missing correct shielding. Listed here are just a few mounting concepts:
On prime of your GoPro/HD digital camera.
On prime of the body if utilizing an under-slung battery setup.
On a mast to raise the GPS away from the quad. Nevertheless, be cautious of proximity to VTX antennas.
Getting a GPS Lock Sooner
Most GPS modules characteristic a small battery to retailer satellite tv for pc information and time, aiding sooner lock-on. As soon as the GPS has locked onto satellites, it retains their positions for fast reconnection after battery adjustments. In case your GPS constantly takes lengthy to lock, examine if its battery is depleted utilizing a multimeter. Decrease interference as a lot as potential—as an example, by relocating a robust VTX, particularly should you’re on a 1.3GHz FPV setup. Climate circumstances like cloudy days may also influence GPS sign high quality.
For extra tips about optimizing BN220 for elevated satellite tv for pc locks, try my devoted tutorial: https://oscarliang.com/gps-settings-u-center/
Strategies immediately from Betaflight Builders
I like to recommend 10 satellites. [And] Await 30s after [you have] 10 satellites for altitude to stabilise [before taking off].
All the time verify regular GPS Rescue behaviour in the beginning of a vital flight by testing with the failsafe change. Set the change to right away enter Stage 2. You’ll be able to enter and go away GPS Rescue by way of the change with instant on and off impact. Examine that the quad rotates and flies in the direction of house and does the best issues earlier than you’re so distant {that a} true failsafe could happen.
ALWAYS CHECK that the Dwelling Arrow factors immediately again in the direction of house after takeoff! Generally, should you take off and spin round throughout arming or instantly on takeoff, the quad’s angle info can change into corrupted, and the Dwelling Arrow can level the improper method. It’s greatest to arm cleanly and fly away from Dwelling in a straight line at an inexpensive pace instantly after takeoff. Watch the Dwelling Arrow rigorously to make sure it rapidly factors again to Dwelling. If the Dwelling Arrow factors the improper method when a failsafe happens, the GPS Rescue will initially fly off within the improper route, and in some circumstances, chances are you’ll lose the quad.
Flawed Path in Rescue Mode?
With out a compass, rescue mode ought to nonetheless work because the quads calculate route by GPS information comparability.
Originally, your quad may be wandering round and even flying in the direction of the improper route however finally it ought to self-correct. With weak GPS connection, it may possibly take longer to right.
If you’re utilizing a compass and it’s flying the improper route, then perhaps there’s one thing improper with the compass, or perhaps it’s not calibrated correctly. On this case strive turning off magnetometer in Betaflight 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 may be 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 price, and with 9600 baudrate the GPS is just not dependable sufficient for GPS options. It’s greatest to make use of a {hardware} serial port (any TX and RX pins on the FC), and set baudrate to at the very least 57600.
Not Getting GPS Lock
Interference out of your quad’s electronics, such because the VTX, telemetry-equipped radio receivers, and even wires carrying important present, can hinder your GPS’s potential to lock onto satellites. Should you’re going through difficulties attaining a GPS lock, think about the next steps:
- Energy the Flight Controller (FC) by way of USB to examine if it powers the GPS module. If not, transfer the GPS module’s energy connection to a special pad on the FC that will get energy from the USB port.
- Isolate the FC’s Energy Provide: Powering solely the FC with out the VTX will help you get a faster GPS lock. Nonetheless, it’s advisable to mount your GPS so far as potential from each the VTX and RX antennas to reduce potential interference.
- Shielding Electrical Wires: shielding wires that conduct important present can mitigate interference. These wires can act like antennas, doubtlessly disrupting GPS indicators.
GPS satellites function on two frequencies, L1 1575.42MHz and L2 1227.60MHz. Consequently, a 1.3GHz FPV setup may intervene together with your GPS. The vast majority of pilots use 5.8GHz, which usually avoids this downside. Nevertheless, given the weak GPS sign—originating from satellites in area—even robust close by indicators may cause interference. Thus, positioning the GPS module away from any transmission sources is essential.
Working GPS wires beneath the VTX may cause points, notably if the VTX lacks ample RF shielding. This RF noise can compromise GPS performance. For instance, the Avatar VTX V1 was recognized to trigger GPS issues when wires are routed beneath it. A possible repair entails grounding the VTX’s shielding. Alternatively, shielding the wires between the GPS and FC—and making certain they’re grounded—may supply an answer.
I attempted to defend wires with foil in considered one of my builds, then linked the foil to a floor pad on the FC. After wrapping it with fabric tape to forestall short-circuiting the body, I seen minimal enchancment. Whereas some have reported optimistic outcomes with this modification, it’s value exploring if different simple options are unavailable.
Didn’t Activate GPS After Updating Betaflight
Should you’re unable to allow GPS after flashing the newest Betaflight model, it’s potential that some options together with GPS had been excluded from the compiled firmware – a brand new characteristic referred to as Cloud Construct System.
To confirm if that is the issue, enter the next command within the CLI:
characteristic gps
Ought to the CLI reply with “gps not out there,” it signifies that the GPS performance was not included in your FC’s Betaflight firmware. To resolve this, you’ll must reflash your FC. This time, be certain that the GPS choice is chosen within the Cloud Construct system throughout compilation: https://oscarliang.com/flash-update-betaflight/#Cloud-Construct-System
Understanding GPS Coordinates Precision
When displaying GPS coordinates within the OSD, you’re supplied with choices to decide on the variety of decimal locations proven—presently, solely 4 and seven decimal choices can be found. This choice immediately influences how precisely you possibly can pinpoint a location on a map primarily based on the GPS information.
The “Decimal Levels” Wikipedia web page supplies an in depth desk evaluating diploma precision to bodily distance:
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
It’s essential to distinguish between accuracy and precision on this context. The GPS could show a excessive diploma of precision (variety of digits), however not all decimal locations could replicate true accuracy. Which means that whereas your GPS can report coordinates to a really tremendous decision, the precise accuracy—how shut these coordinates are to the actual location—could range.
Edit Historical past
- Oct 2018: Tutorial creation.
- Aug 2020: Updates for GUI and CLI parameter adjustments, addition of throttle settings.
- Feb 2023: BF4.4 replace with auto-landing characteristic.
- Mar 2024: BF4.5 replace.
