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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 robotically in a failsafe or when your video feed will get sketchy. On this tutorial, I’m going to stroll you thru organising GPS Rescue Mode, testing it, and I’ll additionally share some recommendations on enhancing its efficiency and troubleshooting widespread points.
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Why GPS Rescue is a Sport-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 rely 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, nevertheless it 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 geared up with the older M8 chip, which means it typically 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’ll be able to attempt optimizing the settings as proven right here.
Get the BN-220 right here:
For those who’re focused on 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:
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 World GNSS programs (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 far 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 harm. It’s usually 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 building, elements location and soldering. Inserting small nicks within the centre of the lengthy edges, or corners, can nice 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, when you’re making use of conformal coating for water resistance, keep away from masking 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 Mandatory?
A compass (as generally known as magnetometer in Betaflight) is for figuring out instructions.
Some GPS modules supply built-in compass, which will be related to the FC by way of the i2c port (SCL and SDA). Nonetheless, Betaflight Rescue Mode doesn’t require a compass to work, it could work out its path from GPS information.
In truth, an improperly calibrated compass would possibly trigger extra points than it solves. In my exams, Rescue mode labored completely nice with out a compass.
How one 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 accessible 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 to 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, characteristic 4V5 pads. These are basically the identical as 5V pads however have the additional benefit of drawing energy from USB. That is significantly useful for these instances when the GPS is taking some time looking for satellites. Through the use of 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. Be aware that some FCs would possibly supply 5V pads powered by USB however underneath totally 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 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 underneath the Different Options part. If GPS all the time deactivates after a reboot, it may 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 underneath “Sensor Enter.” Betaflight helps numerous 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 stop resetting the house location with every arm/disarm cycle till you unplug the battery.
- Select Auto-detect for Floor Help Kind to reinforce positioning accuracy.
- Save and Reboot.
After organising, the GPS indicator on the prime of the configurator ought to gentle 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, examine for
- GPS is just not powered? Attempt plugging in battery?
- Incorrect parameters, as an illustration, incorrect baud charge or protocol.
- Incorrect wiring, attempt 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 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. For those who 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 at the very least 4 satellites and might take a couple of minutes.
If 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, generally known as a “chilly begin”. Subsequent begins are usually faster because the module remembers satellite tv for pc positions (for instance if 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 underneath 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” (often blue) and “PPS” (often 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 should 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’ll be able to show GPS data 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 path to residence and extra.
To know what number of satellite tv for pc have been acquired, place the gps sats component 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 if you purchase extra satellites.
You may as well 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 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 could 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 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 lets you maintain monitor of the final recognized place of your plane. This may be useful for looking for 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 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 outcome within the drone drifting whereas in Angle mode.
To check Angle mode, attempt hovering the drone to see if it’s self-levelling as anticipated. Keep in mind, Angle mode makes use of solely the Accelerometer and Gyro, so it gained’t maintain 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’ll be able to trim the accelerometer within the Configuration tab to reduce it (however unlikely to utterly remove it so don’t fear).
Additionally, pay attention to the throttle place throughout hover. This worth can be helpful when organising Rescue mode later.
Enabling GPS Rescue Mode in Failsafe
Navigate to the Failsafe tab within the Betaflight Configurator. For those who can’t discover this tab, ensure you’ve enabled the “Professional Mode” choice on the prime of the display (subsequent to the Replace Firmware button).
Below Stage 2, choose GPS Rescue. Now, in case your drone enters failsafe, it should 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 dropping radio sign. By default, it could simply drop to the bottom, however with Rescue Mode, it should 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 deliver the quad again.
Whereas setting GPS Rescue as your failsafe methodology is helpful, it’s not suited to all environments. For example, it’s not advisable in bando, forests, stadiums, or indoors. Dropping management underneath a tree or inside a constructing might outcome 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 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 path.
- 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 residence, however it should ultimately 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 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 swap, regaining full management is so simple as disengaging that swap.
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 swap, merely disengage the failsafe swap — no have to wiggle the sticks.
GPS Rescue Settings
Settings for GPS Rescue mode can be found within the Failsafe tab.
It’s a must to tweak the settings in Betaflight to make it work to your specific setup and setting. Be certain that to take a look at the Betaflight wiki to completely perceive what the parameters do: https://github.com/betaflight/betaflight/pull/11579). The default is a reasonably 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 checklist of GPS associated parameters. But it surely’s simpler to alter 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 a better 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 will depend on the ability of the quad. For those who set a giant angle it is best to anticipate some overshoot.
If you’re unsure, simply attempt the default worth and see the way it carry out in testing.
You want to allow Accelerometer and should 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 properly for my 5″.
Preliminary Altitude (meters) – at what minimal peak the drone returns residence relative to the take off level. It must be excessive sufficient to keep away from timber, 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 obtained some tall timber 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’ll be able to’t set it decrease than that.
I go away it at default, 30m.
Floor velocity (meters/second) – Be aware when coming into this worth in GUI, the unit is totally 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 path could be extra correct and replace quicker in increased 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 gained’t work.
Throttle minimal, Throttle most, Throttle hover – these are the min, max and hover throttle values you wish 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 affordable charge (it must be decrease than your hover level).
To set hover level, it’s good 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 totally different. Use the “Throttle %” OSD component to get the precise worth as a substitute of simply guessing. In response to data 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. Alter these primarily based in your setting, climate situation and your quad’s energy. I usually simply go away it to default for my 5″ and it really works fairly properly. For those who use Li-ion packs or low C-rating LiPo, perhaps use a decrease Ascend charge.
Minimal Satellites – Your quad gained’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 will likely 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.
Be aware that when you take off earlier than the GPS attain the minimal quantity of satellites, it gained’t know the place residence is precisely. Extra satellites means higher place accuracy, you’ll be able to cut back the variety of sats however the place accuracy will go down.
By enabling “Enable arming with out repair“, you’ll be able to nonetheless arm the quad when satellite tv for pc locks is under the “minimal Satellites” quantity. I often 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 each time I’m flying in a brand new spot, over water or diving down cliffs, I all the time watch for satellite tv for pc lock.
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 hassle getting these many sats (or it takes a very long time), try my tutorial on how one can increase your GPS receiver efficiency. Get a brand new GPS when you should, they solely price $15, a terrific funding for safeguarding 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 person outlined worth
- Present altitude is no matter peak that the quad is at when GPS rescue mode is activated
The choice will depend on your setting. Most altitude might be the most secure choice in my view, nevertheless it’s not all the time the correct choice say when you had been diving a mountain in that flight, you can be losing power climbing again to the max altitude when Rescue mode is activated. Be adaptive to the totally different setting and missions.
Sanity Checks – when set to “ON”, it always displays GPS Rescue mode situations, for instance:
- is GPS nonetheless related
- are we getting good variety of satellite tv for pc repair
- are we at the very least 100 meters away from residence? (distance will be modified)
- are we getting nearer to the house, and we didn’t hit an impediment
If any of those situations are usually not met, it should abort rescue mode and your quad will simply disarm and drop to the bottom. So yea, it’s not splendid if you’re flying over unrecoverable locations like ocean or mountains, however typically, 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 swap 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 solely, 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.
How one can Manually Activate GPS Rescue?
Aside from failsafe, you can too manually activate GPS Rescue by flipping a swap in your radio transmitter. It’s helpful in emergency conditions like dropping orientation (e.g. when flying LOS) or your FPV system stops working, you may 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
In the course of the stage 1 of a failsafe, the drone will go into channel fallback, which suggests every radio channel can be set to particular values. You would possibly wish 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. If 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 incorrect because it fails one of many sanity checks and trigger the drone to only drop to the bottom.
A workaround could 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, heart 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!
How one can Take a look at GPS Rescue
Right here’s how I’d check GPS Rescue.
Initially, assign a swap to GPS Rescue and ensure it could certainly deliver your quad residence as meant. If something goes incorrect, disengaging the swap ought to provide you with full management once more.
Subsequent, assign a swap to Failsafe within the Modes tab in Betaflight. It emulates full failsafe mode in Betaflight (similar to if you lose RC sign). It is a lot safer than testing by turning off your radio, as a result of you’ll be able to disengage anytime you need utilizing a swap.
Be aware that that is just for testing GPS Rescue mode, as quickly as you end testing, it is best 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 swap. At this level your quad will go into Rescue mode, and your radio controls can be locked out. Now examine when you can deactivate failsafe and take again management.
If you find yourself testing this on the bench, with the USB cable related, the Rescue mode field gained’t flip yellow like different modes. That is nice so long as the small yellow bar can transfer to the activation vary.
It’s helpful to have these GPS associated data in your OSD, they are going to enable you perceive what your quad is doing. You may as well 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 check it in an open subject 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 swap, 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’re flying residence. If it’s pointing down, means you’re flying away from residence. The arrow may be pointing the incorrect path initially, that is regular. Simply be certain the quad isn’t flying the exact opposite path.
You’ll be able to give up failsafe mode by flipping the swap at any time and resume full management.
For those who don’t disengage, it should keep it up flying residence. When the quad reaches residence, it should hover for a bit and begins to slowly descend however the motors can be pulsating… till it hits the bottom and disarms robotically.
Repeat the process many times till you’re feeling snug with it.
As soon as you’re performed with testing, take away Failsafe from the Modes tab.
Suggestions
Finest Locations to Mount GPS Module
Be certain that the GPS eramic patch antenna has a transparent view of the sky for locking onto satellites, and nothing is masking it which might weaken GPS sign, particularly conductive supplies similar to carbon fibre, electrical wires, and steel.
Keep away from EMI from different electrical elements in your quad. Widespread RF interference sources that may affect GPS efficiency are HD digital camera and video transmitter. Mount your GPS as far-off from these units as potential.
One widespread mistake is mounting the GPS the other way up. The GPS receiver antenna must be going through up, it’s a flat sq. with small steel round half within the center. There must be no elements in any respect on this facet. For example, that is the ceramic antenna in a GPS receiver, it must be going through up.
Be certain that there’s nothing blocking or interfering with the GPS unit at anytime. Mount it on prime of your quad, as far-off from the VTX / RX antennas as potential (many radio receivers can really transmit sign as properly as a consequence of 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 properly in the event that they don’t have the suitable shielding.
Listed below are some concepts the place/how one 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 far-off from the quad as potential. However in all probability 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 if you end up doing a roll or inverted yaw spin).
Earlier than your flight, it could take some time to get a GPS lock. You would possibly wish to energy in your quad and GPS beforehand to “heat up” first, e.g. on the way in which to the flying subject.
How one can 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 areas, so after you alter the drone’s battery (the GPS module is powered off briefly), the GPS lock often 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 should take for much longer to get a lock.
For this reason 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 all the time takes a very long time to get a lock, it’s price checking if the battery is lifeless (with a multimeter). Additionally be certain there’s as little interference to the GPS as potential, for instance if you’re using1.3GHz FPV setup, attempt transferring highly effective VTX away from the GPS. Cloudy day also can impact GPS sign high quality.
Additionally try my put up about optimizing GPS settings to get extra satellite tv for pc locks.
Phrases from Betaflight Devs
I like to recommend 10 satellites. [And] Look ahead to 30s after [you have] 10 satellites for altitude to stabilise [before taking off].
At all times verify regular GPS Rescue behaviour firstly of a essential flight by testing with the failsafe swap. Set the swap to instantly enter Stage 2. You’ll be able to enter and go away GPS Rescue by way of the swap with instant on and off impact. Examine that the quad rotates and flies in the direction of residence and does the correct issues earlier than you’re so far-off {that a} true failsafe might happen.
ALWAYS CHECK that the Dwelling Arrow factors straight 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 turn into corrupted, and the Dwelling Arrow can level the incorrect means. It’s finest to arm cleanly and fly away from Dwelling in a straight line at an affordable velocity instantly after takeoff. Watch the Dwelling Arrow fastidiously to make sure it rapidly factors again to Dwelling. If the Dwelling Arrow factors the incorrect means when a failsafe happens, the GPS Rescue will initially fly off within the incorrect path, and in some circumstances, chances are you’ll lose the quad.
Improper path in Rescue?
With no compass, your quad can nonetheless work out path utilizing GPS coordinates. By flying ahead the drone can calculate which means it’s going by evaluating the present place and the earlier place. That’s why initially, your quad may be wandering round and even flying in the direction of the incorrect path however ultimately it ought to right itself. In case your GPS sign is weak or updating too slowly it could take longer to right.
If you’re utilizing a compass and it’s flying the incorrect path, then perhaps there’s one thing incorrect with the compass, or perhaps it’s not calibrated correctly. On this case attempt 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 may be updating too slowly (e.g. 1Hz), attempt to enhance 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 at the very least 57600.
Not Getting GPS Lock
Interference from different electronics similar to your VTX, radio receiver in case you have telemetry, and even close by wires that carry a whole lot of present can stop the GPS from getting a lock. When you have hassle getting a GPS lock, attempt 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 far-off from VTX antenna and RX antenna as potential
- Shielding close by wires also can assist typically. Wires carrying present are like antennas, they may additionally doubtlessly 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 problem. However since GPS sign is so weak (it’s all the way in which from house in any case), any highly effective sign close by could cause interference, due to this fact it is best to mount the GPS module as far-off from any transmitting sources as potential.
If you run your GPS wires to the FC underneath the VTX, it could 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 understood to trigger GPS challenge when operating wires underneath it. Options may very well be correctly grounding the VTX shielding, however you can 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 considered one of my quads, then join the foil to a floor pad on the FC (to floor it). Lastly wrap it with some fabric tape so it doesn’t quick the body. Some folks reported good outcome with this modification, for me the advance is little, nevertheless it’s price a shot if there’s no different straightforward 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 verify that is the case, enter this command in CLI:
characteristic gps
If CLI returns “gps not accessible”, then it means the GPS characteristic isn’t a part of the betaflight firmware in your FC. On this case you’ll have to reflash your FC, this time it is best to be certain GPS included in the Cloud construct system choice when compiling it.
GPS Coordinates Decimals
To show GPS coordinates within the OSD you could have the choices to pick out what number of decimals to show (at the moment solely 4 and seven decimals can be found). It impacts how exact the place is if 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 might report any variety of digits (its precision) however most of the decimal locations may be simply faulty (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
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