It is vitally important that all drone fishing pilots understand the various GPS flight modes and non-GPS flight modes. Most UAV GPS systems are highly accurate and reliable, however the GPS signal from satellites can be interrupted due to interference from various sources. Due to the possibility of GPS interference all drone pilots must be aware at all times of this possibility and be ready to take action to avoid losing the drone. Failure on the part of the drone pilot to understand and be proficient in flying in both GPS and non-GPS flight modes could result in loss of the drone, and the situation will be deemed as user error – not a failure of the drone itself.
When drone fishing, a pilot requires a high level of skill in flying in ATTI/ALT Hold mode due to the chances that the drone will be over water and in the event of an issue, this non-GPS flight skill becomes even more critical.
Global Navigation Satellite System ‘GNSS’
The Global Navigation Satellite System or GNSS comprises of 4 main satellite constellations being.
GPS – The USA’s Navstar Global Positioning System
GLONASS – The Russian Federations Global Navigation Satellite System
Galileo – The European Unions global navigation satellite system
Beidou – China’s GNSS
Depending upon the GPS module your UAV uses, will determine the strength of signal and the number of Global Navigation Satellite systems ‘GNSS’ it will connect to. Most GPS modules will connect to at least 2 concurrent satellite networks’ being GPS and GLONASS, and some can connect to 3 or more satellite networks and include Galileo and BeiDoh. Usually at any given moment in time there will be at least 24 GNSS satellites in orbit over a 12-hour period.
GPS interference and what causes it
GPS interference can be caused due to several factors such as intentional or unintentional GPS jamming, space weather/atmospheric conditions, Electromagnetic fields, and near band width RF interference from other sources.
GPS signal failure – Understanding and what to do in the event of signal interference
The majority of UAV’s have several GPS flight modes such as Loiter, POS Hold, RTL – ‘return to land’. These GPS flight modes are what most drone pilots use when flying their UAV and are unaware of non-GPS flight modes and when to use them.
Most UAVs utilise a GPS module and a barometer.
GPS module: Holds the horizontal position of the drone.
Barometer: Also known as a pressure sensor, it measures the atmospheric pressure and maintains the drone’s height. The drone’s initial height is determined at the start-up stage, and therefore it is vitally important not to move the drone until this start-up procedure is finished.
Non-GPS flight modes such as ALT Hold, Altitude Hold or ATTI mode utilise the Barometer solely and it holds the drone’s height, but not its horizontal position. If wind is blowing in one direction it will naturally push the drone in the direction of the wind.
When to use a non-GPS flight mode
Some advanced drones will advise the pilot that there is a GPS glitch or loss of signal, but many do not. If you have ever heard someone, say, ‘My drone just flew off’, it is more than likely the drone suffered a loss of GPS signal or interference and the drone lost control. If ever this occurs the pilot must select a non-GPS mode such as ALT Hold, Altitude Hold or ATTi mode immediately, and this will require the pilot to have the necessary skills to maintain its horizontal position and manually fly the drone to safety.
It is incredibly important for the safety of the drone that all pilots practice flying in a non-GPS flight mode. If the pilot is not proficient in flying in a non-GPS mode, the chance of losing the drone is highly probable due to a GPS glitch and the incident is determined to be user error – not a malfunction of the drone and warranty is not covered.
Many advanced drones such as the BARRA-CUDA will provide visual and verbal broadcasts informing the pilot in the event of a GPS glitch, and some will after a period automatically select a non-GPS flight mode and advise the pilot.
Practice safely in a non-GPS flight mode
Whenever learning to fly in a non-GPS flight mode you should only attempt this when the wind speed is less than 20kph or lower is advisable. The more you practice the better you will get, and your hand eye coordination will improve – it is a bit like when you flew the drone towards you for the first time and the control sticks left and right are opposite.
When switching to a non-GPS flight mode you will need to adjust the left or right sticks to counter the wind direction and hold position – You are the GPS!
Once you have mastered holding horizontal position then you can begin learning to fly forwards and backwards in addition to maintaining the drone’s horizontal position. Simple exercises such figure of eights will greatly improve your flight skills.
Do’s
- Always fly and maintain a minimum altitude of 20 metres.
- Determine the direction of the wind – as wind direction will determine which way the drone will be moving.
- Always position yourself in the middle of an oval and away from trees or other obstacles and away from people.
- Keep the drone within a circumference of 5-10 metres – if the drone gets away from you simply switch back to a GPS flight mode, bring the drone back to position and try again.
Don’ts
- Never panic as the drone will hold its height – if ever the drone get’s away from you simply return to a GPS flight mode and bring the drone back and try again.
- Never fly in wind speeds exceeding 20kph and lower wind speeds are advisable – be away if you are flying at a park or suburbia wind turbulence will increase the difficulty to control the drone.
- Never fly near obstacles or people.
While all of this may seem daunting, practice does makes perfect. If you recall your first attempt at flying your drone you may have been overwhelmed, but in time and with practice your skills improved, and you became proficient.
