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Betaflight GPS Rescue mode is just 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 robotically 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 recommendations on enhancing its efficiency and troubleshooting frequent 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 most recent 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 rely of what number of instances GPS Rescue has saved my drones.
How one can Select the Finest GPS?
Listed here are the issues when selecting an excellent GPS for Rescue mode:
- M10 GPS is one of the best.
- It Ought to Help UBLOX protocol, keep away from NMEA protocol because it solely helps 1Hz replace charge and that’s too gradual.
- Get the most important GPS you may comfortably slot in your drone – greater GPS comes with greater antenna and it’s higher for sign.
- In case your GPS doesn’t reliably offer you greater than 10 satellites out of doors, it’s dangerous to make use of.
GPS Suggestions
See my GPS testing right here: https://oscarliang.com/gps-review/
High Performer: GEPRC M1025Q
High Performer: HGLRC M100 5883
Smallest Value Having: GOKU GM10 Nano V3
Smallest Value Having: FlyFishRC M10 Mini
Smallest Value Having: HGLRC M100 Mini
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.
Technology of GPS Chip
Most GPS modules for FPV drones use both an M8, M9 or M10 chip. M10 chips are the most recent and provide one of the best efficiency, able to connecting concurrently to 4 World GNSS methods (GPS, Galileo, Glonass, and Beidou). This ends in quicker lock-ons and connections to extra satellites. Regardless of their superior efficiency, the value of M10 GPS is just like M8, making them a cheap improve.
Antenna Scratches
Seen scratches in your GPS antenna’s metallic patch? Don’t fear; this isn’t essentially an indication of defect or harm. It’s usually the results of manufacturing unit tuning to make sure optimum frequency. These kind of 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). Barometer isn’t essential for Rescue mode, however it could enhance altitude estimations accuracy, ends in higher altitude management and extra dependable landings. Simply bear in mind, when you’re making use of conformal coating for water resistance, keep away from coating the barometer.
Some GPS modules provide a built-in barometer for an additional value. In case your flight controller doesn’t have one, including a module with a barometer could possibly be helpful.
Is a Compass Essential?
A compass (as often called magnetometer in Betaflight) is for figuring out which path the drone is heading.
Betaflight GPS Rescue Mode DOES NOT require a compass to work, however utilizing one can enhance Rescue mode efficiency, particularly in conditions with crosswinds or throughout place maintain, as a result of it gives correct heading info no matter motion path. With out a compass, Betaflight estimates heading from GPS information, which could be inaccurate when the drone is drifting (like in a crosswind), inflicting inefficient corrections.
Nevertheless, whereas a compass can improve efficiency, it provides complexity. It requires cautious setup in Betaflight, additional wiring, correct mounting orientation, and calibration. It’s additionally delicate to electrical noise, which might result in inaccurate readings. For most individuals, a compass isn’t essential until you’ve particular necessities.
Some GPS modules have built-in compass: GPS with out compass have 4 wires, whereas these with a compass usually have 6 wires. The 2 additional wires are to hook up with the i2c port on the flight controller (SCL and SDA).
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)
- GPS SCL – FC SCL (if GPS has a compass)
Keep away from utilizing Softserial in 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 steady 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 notably useful for these instances when the GPS is taking some time trying to find satellites. By utilizing the USB for energy, you keep away from the danger of your VTX overheating whereas ready on the bottom with a LiPo battery plugged in. It additionally helps the GPS lock quicker for the reason that VTX isn’t transmitting and inflicting interference. Observe that some FCs may provide 5V pads powered by USB however beneath completely different labels; examine with a multimeter if not sure.
How one can Setup GPS in Betaflight
GPS Rescue mode in Betaflight is repeatedly evolving, so it’s essential to make use of the most recent 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 all the time deactivates after a reboot, it could be as a consequence 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. In case you are not sure what baudrate your GPS module helps, choosing AUTO normally works.
The really helpful baud charge for 10Hz GPS information charge is 38400 or 57600. There’s little to be gained by utilizing 115200 with 10hz, however utilizing decrease baud charges cut back the CPU load and are extra immune to electrical noise.
| GPS Information Charge | Baud Charge | CPU Load | Feedback |
| 20Hz | 115200 | Highest | M10 solely; check rigorously! |
| 10Hz | 38400 or larger | Medium | 10Hz and 57600 is really helpful for GPS Rescue |
| 5Hz | 19200 or larger | Medium | Okay settings for normal use |
| 1Hz-2Hz | 9600 or larger | Least | Too gradual for clean GPS rescue, OK for easy place/pace data |
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 stop 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 pink icon means GPS is speaking to the FC however with no lock, and a yellow icon signifies a profitable GPS lock.
If the GPS indicator stays off, examine for
- GPS isn’t powered? Strive plugging in battery?
- Incorrect parameters, as an example, improper baud charge or protocol.
- Incorrect wiring, strive swapping TX and RX.
How one 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 occurring.
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 occurring. If you happen to see nothing, there could also be a problem with energy, UART connection, or your setup.
Ready for GPS Lock
Getting a GPS lock, or “3D repair,” requires locking onto not less than 4 satellites and may take a couple of minutes.
Whenever you energy up the GPS module for the primary time in a brand new location, it all the time takes longer to seek for satellites, often called a “chilly begin”. Subsequent begins are typically faster because the module remembers satellite tv for pc positions (for instance whenever you change battery).
It’s more durable to get a lock indoor. If it’s a must to 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 reveals 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 pink).
Flashing blue (TX) signifies UART connection. Whether it is off, then the GPS isn’t 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 pink (PPS) signifies the 2D/3D repair standing of the GPS. If “PPS” is off then you definitely 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 possibly can show GPS data within the OSD. Try this tutorial about Betaflight OSD if you’re not acquainted with it. You possibly can show GPS coordinates, distance and path to residence and extra.
To know what number of satellite tv for pc have been acquired, place the gps sats aspect in your OSD. 6-8 is the minimal for rescue mode to work, the extra the higher. Your GPS coordinates may 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 beneath is right, which might offer you an accuracy of about 2.5 meters or much less. It could 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
After you have 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 – resembling ExpressLRS and Crossfire.
This lets you log GPS coordinates in your radio, it lets you preserve monitor of the final recognized place of your plane. This may be useful for trying to find the misplaced quadcopter when 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 appropriately.
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 may end result 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 gained’t preserve the drone completely stationary like a DJI drone would. A slight drift as a consequence of weight distribution and wind is regular, so long as the drone stays steady. If drifting is noticeable, you may trim the accelerometer within the Configuration tab to reduce it utilizing stick instructions on the bottom (however unlikely to utterly eradicate it so don’t fear).
Additionally, be aware of the throttle place throughout hover (with a half discharged battery). This worth shall be helpful when establishing Rescue mode later.
Disabling Magnetometer
As really helpful by Betaflight Builders, until you’re completely certain that your Magnetometer (aka compass) has been correctly calibrated and is working appropriately, in any other case it’s best to disable it (within the Configuration tab, beneath Accelerometer and Barometer). Betaflight Rescue Mode doesn’t rely on Magnetometer so it’s high quality to disable it.
To examine in case your magnetometer is working, examine the compass worth in your telephone (set to indicate True North, not Magnetic North), with the heading on Configurator’s major opening display screen, the GPS tab in Configurator, or the Sensors tab debug line 5 in debug mode GPS_RESCUE_HEADING, and examine that each are inside 10 levels of one another. If the heading all the time begins at North, and follows quick actions shortly however then jumps to another worth, the Magazine isn’t proper.
Keep away from Utilizing 8K/8K
As per builders suggestions, keep away from 8K PID Loop Frequency, use 4K or decrease. That is because of the CPU intensive nature of Rescue Mode, particularly with excessive baud charge resembling 56700 or larger. Reducing PID looptime will go away extra CPU headroom for Rescue mode to work extra reliably.
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 to’ve enabled the “Professional Mode” choice on the prime of the display screen (subsequent to the Replace Firmware button).
Underneath 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 will simply drop to the bottom, however with Rescue Mode, it’s going to try and 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 convey the quad again.
Whereas setting GPS Rescue as your failsafe technique is useful, it’s not suited 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 may end result within the drone crashing into obstacles when Rescue mode engages.
When 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:
- Self Stage: The drone allows Angle Mode and self degree.
- Ascend: The drone climbs to a user-configured altitude.
- Rotate: It turns in the direction of the house path.
- Fly House: The drone begins its journey again to the launch level. The flight may not be a clean cruise, because the drone may pitch forth and again making an attempt to manage its pace.
- Descend: As soon as close to the launch level, it begins descending slowly. The descent could be uneven, with the motors making pulsating sounds because the drone tries to decelerate.
- Land: Upon touching the bottom, the drone robotically disarms, with motors terminating primarily based on affect, not primarily based on altitude.
How one 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 have to 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 atmosphere. I extremely advocate visiting the Betaflight wiki to understand a full understanding of what every parameter entails: https://github.com/betaflight/betaflight/pull/11579. The default settings provide a strong start line, particularly for five″ freestyle drones.
Right here, I’ll stroll you thru the settings, sharing the values I exploit on my 5″ freestyle drone and the reasoning behind every alternative.
Accessing all settings is simple 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 residence.
- Most altitude is the very best altitude your quad is flown throughout that flight
- Fastened altitude is only a predefined worth
- Present altitude is no matter top that the quad is at when GPS rescue mode is activated
The only option varies with every flight’s context and atmosphere. Most altitude could be a protected choice, but it surely’s not all the time the suitable choice. As an example, when you was diving a mountain in that flight, you can be losing vitality climbing again to the max altitude when Rescue mode is activated. When flying over ocean the place there’s no obstructions, mounted altitude could possibly be an excellent choice. Use frequent sense, be adaptive to the completely different atmosphere and missions.
Preliminary Climb (meters): The space the quad will climb to this top above the present altitude, when a rescue is initiated and the altitude mode is ready to Present Altitude. Additionally added when in Max Altitude Mode.
Return Altitude (meters): Solely applies in Fastened Altitude mode. This determines the drone’s return altitude relative to its takeoff level. It ought to be excessive sufficient to clear any obstacles like bushes and buildings however not so excessive that it excessively consumes battery throughout ascent. For my flying spots, which options tall bushes and small hills, I’ve bumped this as much as 50 meters.
Ascend/Descend Charge (meters/second): These charges rely in your atmosphere, climate, and quad’s energy. For my 5″ setup, the defaults ought to work effectively. If utilizing Li-ion packs or low C-rating LiPo, think about a decrease ascend charge.
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 approach too gradual for many drones, I usually double that to 12m/s (43km/h) for micro drones, or 17m/s (60km/h) for five″ and seven″ drones. The quad’s journey path can be extra correct and replace quicker in larger pace (within the absence of a compass). Don’t set it to decrease than 2m/s or orientation gained’t work. Observe 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. Perhaps helpful for heavier, excessive drag and low authority drones. In windy circumstances, a better angle could be essential for sustaining pace, particularly for smaller quads. Nevertheless, with an excessively steep angle the drone may lose altitude and crash. Uncertain of what to set? Beginning with the default worth of 40 levels is a protected wager—it’s labored effectively for my 4inch and 5inch setup.
Descend Distance (meters): That is the distance from residence 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 ought to be above your hover level), set min to maintain the props spinning at an affordable charge (it ought to be decrease than your hover level). I left Throttle Min/Max at default.
To set Throttle Hover, it is advisable to decide an correct worth. Check fly your quad and see at what throttle it hovers (simply sufficient throttle to maintain the quad afloat). Use the “Throttle %” OSD aspect to get the precise worth as a substitute of simply guessing. Ideas, the perfect worth ought to trigger the quad to climb a bit whereas in degree mode, if the hover worth is ready too low, the quad will drop early within the rescue – probably into the water! And the hover throttle worth goes to be barely completely different is determined by battery voltage, so that you may marvel, what throttle worth ought to I exploit? Nicely you bought to ask your self, at what battery voltage you’re more than likely going to get a failsafe? It’s acquired to be when the drone is the fartherest from you proper? And you’re most likely simply earlier than half approach via the battery, round 3.8V to three.9V. So use the hover throttle worth at this voltage.
Minimal Distance to House (meters): If Rescue begins too near residence (inside this minimal distance), the drone will fly away on its present heading till this distance from residence, and begin the traditional Rescue behaviour. I go away this on the default 15 meters.
Minimal Satellites: A minimal of 8 satellites ensures dependable Rescue mode operation. If you happen to take off earlier than the GPS attain the minimal quantity of satellites, it gained’t know the precise residence location. Extra satellites imply higher accuracy. I go away this on the default, 8.
Permit Arming With out Repair: This selection gives flexibility by permitting arming with no GPS lock. I allow this for the comfort of check flights, however make sure you get a GPS lock for whenever you intend to make use of GPS Rescue Mode.
Beware that GPS Rescue WILL NOT work for that flight when you arm earlier than getting a satellite tv for pc lock (as a result of it doesn’t know the house place).
When you have bother getting these many sats (or it takes a very long time), take a look at my tutorial on easy methods to increase your GPS receiver efficiency. Get a brand new GPS when you should, they solely value $15, a fantastic funding for shielding your $300 quad!
Sanity Checks: When set to “ON”, it displays GPS Rescue mode circumstances, for instance:
- Is the GPS nonetheless related to the FC?
- Are we getting an excellent variety of satellite tv for pc locks?
- Are we not less than 20 meters away from residence?
- Are we getting nearer to the house, and we didn’t hit an impediment?
If any of those circumstances usually are not 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 typically, 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 well-liked choice.
It’s dangerous to show off Sanity Examine completely, you may 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.
How one can Manually Activate GPS Rescue?
In addition to failsafe, you’ve the choice to manually set off GPS Rescue by flipping a change in your radio transmitter. This function is useful throughout emergencies, resembling shedding your approach or encountering points together with your FPV system, permitting your drone to autonomously return residence.
Go to the Modes tab in Betaflight Configurator and assign an AUX channel particularly for GPS Rescue Mode. If you happen to’re new to configuring modes, take a look at 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 ready to predefined values. It’s clever to evaluation these values to make sure security.
By default, the Channel Fallback for Throttle is ready to “Auto,” which reduces the throttle to zero, ends in the motors stopping momentarily in the course of the guard time. This interruption may 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 choose setting the throttle to the hover worth, in addition to centering all roll/pitch/yaw channels (set them to 1500 or auto), and prompts the change for Angle mode. This fashion, the quad ranges itself out when failsafe occurs, earlier than GPS Rescue engages.
Bear in mind, by no means set throttle to zero throughout Stage 1 of failsafe!
How one can Check GPS Rescue
Testing GPS Rescue is an important step earlier than counting on it in real-world eventualities. Right here’s my method to making sure it really works as anticipated.
The Setup
First, assign a change in your radio to GPS Rescue to substantiate it could certainly convey your drone residence. Ought to something not go based on 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 may exit the mode every time essential utilizing the change. It’s necessary 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 make sure that activating the Failsafe change certainly triggers Rescue mode, throughout which your radio sticks shall be momentarily locked out. Confirm when 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 appropriately.
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 charge mode, and “Angle” in angle mode.
Subject Testing
For an precise check, select an open space free from obstacles and folks, with mushy grass. Guarantee you’ve a legitimate residence level earlier than taking off – ideally the OSD ought to present not less than 8 satellites or extra.
Take off and fly 50-100 meters away, near the bottom, then set off Failsafe mode utilizing the change. The quad ought to promptly change to GPS Rescue mode, indicated by flight mode within the OSD because it adjustments from AIR to RSC.
Take note of the house arrow within the OSD; when it’s pointing up, means you’re heading residence, when pointing down means you’re flying away. Initially, the arrow may level within the improper path if you’re not utilizing a magnetometer, which is regular because it takes 5 to 10 seconds for Betaflight to work out which path it’s heading—simply make sure the drone isn’t flying the exact opposite path after 10 seconds.
You possibly can stop failsafe mode at any time by flipping the change, regaining full management instantly.
If you happen to select to not disengage, the drone will proceed flying again to the launch level. Upon arrival, it’s going to hover briefly earlier than beginning a gradual descent, throughout which the motors could pulsate, till it safely lands and disarms robotically.
You could need to repeat this course of a number of instances, till you’re assured within the system’s reliability. After thorough testing, don’t neglect to take away Failsafe from the Modes tab.
Ideas and Troubleshooting
Finest 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 overlaying 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 parts 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 far-off from these units as attainable.
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 middle, ought to all the time face upwards. Guarantee no parts impede this facet. Within the following picture for instance, the ceramic antenna is going through up.
The place to Mount GPS
Listed here are the issues when mounting your GPS on a quad:
- Tthere’s nothing blocking the GPS unit
- The ceramic antenna is pointing to the sky
- Best mounting spots embrace the highest of your quad, far-off from VTX and RX antennas
- Stay away from potential radiation sources like HD cameras that may lack correct EMI shielding
Listed here are a number of mounting concepts:
On prime of your GoPro/HD digicam.
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.
One among my favorite methods is to put in the GPS on the battery strap.
Getting a GPS Lock Sooner
Most GPS modules function a small battery to retailer satellite tv for pc information and time, aiding quicker 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 persistently takes lengthy to lock, examine if its battery is depleted utilizing a multimeter. Reduce interference as a lot as attainable—as an example, by relocating a strong VTX, particularly when you’re on a 1.3GHz FPV setup. Climate circumstances like cloudy days may also affect GPS sign high quality.
For extra recommendations on optimizing BN220 for elevated satellite tv for pc locks, take a look at my devoted tutorial: https://oscarliang.com/gps-settings-u-center/
Ideas immediately from Betaflight Builders
I like to recommend 10 satellites. [And] Look forward to 30s after [you have] 10 satellites for altitude to stabilise [before taking off].
All the time verify regular GPS Rescue behaviour initially of a important flight by testing with the failsafe change. Set the change to right away enter Stage 2. You possibly can enter and go away GPS Rescue by way of the change with fast on and off impact. Examine that the quad rotates and flies in the direction of residence and does the suitable issues earlier than you’re so far-off {that a} true failsafe could happen.
ALWAYS CHECK that the House Arrow factors immediately again in the direction of residence after takeoff! Typically, when you take off and spin round throughout arming or instantly on takeoff, the quad’s angle info can change into corrupted, and the House Arrow can level the improper approach. It’s finest to arm cleanly and fly away from House in a straight line at an affordable pace instantly after takeoff. Watch the House Arrow rigorously to make sure it shortly factors again to House. If the House Arrow factors the improper approach when a failsafe happens, the GPS Rescue will initially fly off within the improper path, and in some circumstances, you could lose the quad.
Flawed Path in Rescue Mode?
With out a compass, rescue mode ought to nonetheless work because the quads calculate path via GPS information comparability.
Initially, your quad could be wandering round and even flying in the direction of the improper path however finally it ought to self-correct. With weak GPS connection, it could take longer to right.
In case you are utilizing a compass and it’s flying the improper path, 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 take a look at 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 could 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).
Checking GPS Accuracy (HDOP/PDOP)
HDOP and PDOP are measurements of how correct your GPS is. Decrease values imply higher accuracy. In INAV they use HDOP and in Betaflight 4.5, they use PDOP.
HDOP (Horizontal Dilution of Precision) and PDOP (Place Dilution of Precision) are each measures of GPS accuracy, however they concentrate on completely different facets. HDOP primarily displays the accuracy of horizontal place (longitude and latitude), whereas PDOP considers the accuracy of each horizontal and vertical positioning (latitude, longitude, and altitude).
You possibly can show PDOP in Betaflight OSD by coming into set osd_gps_sats_show_hdop = ON within the CLI. Here’s what the worth means:
- 1.0 to 1.5: Glorious accuracy, very steady GPS lock.
- 1.5 to 2.0: Acceptable, minor drifting may happen.
- 2.0 to three.0+: Poor accuracy, vital place drift is frequent.
Extra satellites usually decrease your PDOP/HDOP, bettering GPS accuracy. Digital interference, particularly from units like GoPro cameras or Wi-Fi, can negatively have an effect on PDOP/HDOP and trigger instability in GPS maintain mode.
Keep away from Softserial
Keep away from utilizing Softserial for GPS Rescue because it’s too gradual. You could use it to show GPS associated data on the OSD, but it surely’s merely not dependable sufficient for GPS Rescue. It’s finest to make use of a {hardware} serial port (any TX and RX pins on the FC), and set baudrate to not less than 57600.
Not Getting GPS Lock
Interference out of your quad’s electronics, such because the VTX, telemetry-equipped radio receivers, and even wires carrying vital present, can hinder your GPS’s skill to lock onto satellites. If you happen to’re going through difficulties reaching 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 unique 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 may also help you get a faster GPS lock. However, it’s advisable to mount your GPS so far as attainable from each the VTX and RX antennas to reduce potential interference.
- Shielding Electrical Wires: shielding wires that conduct vital 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 intrude together with your GPS. Nearly all of pilots use 5.8GHz, which typically avoids this drawback. Nevertheless, given the weak GPS sign—originating from satellites in area—even sturdy close by indicators could cause interference. Thus, positioning the GPS module away from any transmission sources is essential.
Operating GPS wires beneath the VTX could cause points, notably if the VTX lacks enough 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 includes grounding the VTX’s shielding. Alternatively, shielding the wires between the GPS and FC—and making certain they’re grounded—may provide an answer.
I attempted to defend wires with foil in certainly one of my builds, then related the foil to a floor pad on the FC. After wrapping it with material tape to stop short-circuiting the body, I seen minimal enchancment. Whereas some have reported optimistic outcomes with this modification, it’s price exploring if different simple options are unavailable.
Did not Activate GPS After Updating Betaflight
If you happen to’re unable to allow GPS after flashing the most recent Betaflight model, it’s attainable that some options together with GPS have been excluded from the compiled firmware – a brand new function referred to as Cloud Construct System.
To confirm if that is the issue, enter the next command within the CLI:
function 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 have to reflash your FC. This time, make sure 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—at the moment, solely 4 and seven decimal choices can be found. This choice immediately influences how precisely you may pinpoint a location on a map primarily based on the GPS information.
The “Decimal Levels” Wikipedia web page gives 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 whereas your GPS can report coordinates to a really high quality decision, the precise accuracy—how shut these coordinates are to the actual location—could fluctuate.
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 function.
- Mar 2024: BF4.5 replace.
- Apr 2025: up to date
