First-person view (radio control)

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First-person view (FPV), also known as remote-person view (RPV), or simply video piloting, is a method used to control a radio-controlled vehicle from the driver or pilot's view point. Most commonly it is used to pilot an unmanned aerial vehicle (UAV) or a radio-controlled aircraft. The vehicle is either driven or piloted remotely from a first-person perspective via an onboard camera, fed wirelessly to video goggles or a video monitor. More sophisticated setups include a pan-and-tilt gimbaled camera controlled by a gyroscope sensor in the pilot's goggles and with dual onboard cameras, enabling a true stereoscopic view.

Airborne FPV[edit]

An assortment of FPV aircraft of the popular "Sky Hunter" design at an FPV meetup in Colorado in July 2013

Airborne FPV is a type of remote-control (RC) flying that has grown in popularity in recent years. It involves mounting a small video camera and an analogue video transmitter to an RC aircraft and flying by means of a live video down-link, commonly displayed on video goggles or a portable monitor. When flying FPV, the pilot's view is that of a would be real pilot on board the aircraft and as such does not need to maintain visual line of sight (LOS) of the aircraft compared with regular RC flying. As a result, FPV aircraft can be flown well beyond visual range, limited only by the range of the remote control and video equipment in use. FPV became increasingly common throughout the late 2000s and early 2010s. It is currently one of the fastest growing activities involving RC aircraft, and has given rise to a small but growing industry providing products specifically designed for FPV use. FPV aircraft are frequently used for aerial photography and videography and many videos of FPV flights can be found on popular video sites such as YouTube and Vimeo. For this purpose, many FPV pilots utilize a second, lightweight high-definition on-board camcorder such as a GoPro camera in addition to their standard definition video link(s).

Records[edit]

The current round-trip distance record for an FPV aircraft is 68.9 miles (horizontal distance). Altitudes of up to 33,103 meters above ground (launch site) level have also been achieved, with a mix of weather balloon and RC glider equipment used.[1]

The current speed record for a FPV aircraft is a GPS verified 353 km/h (219 mph) video on YouTube, attained by a UK pilot Benjamin Blackburn flying a modified Multiplex Funjet Ultra.

Equipment[edit]

A FPV pilot flies his aircraft using video goggles while a spotter aims a directional antenna at the plane.

There are two primary components of a FPV setup: the airborne component and the ground component (typically called a ground station). A basic FPV system consists of a camera and an analogue video transmitter on the aircraft with a video receiver and a display on the ground. More advanced setups commonly add in specialized hardware, including on-screen displays with GPS navigation and flight data, stabilization systems, and autopilot devices with "return to home" capability—allowing the aircraft to fly back to its starting point autonomously in the event of a signal loss. Another common feature is the addition of pan and tilt capability to the camera, provided by servos. This, when coupled with video goggles and "head tracking" devices creates a truly immersive, first-person experience, as if the pilot was actually sitting in the cockpit of the RC aircraft.[2] Receiving equipment - commonly referred to as the "Ground Station" - generally consists of an analog video receiver (matching the frequency of the transmitter on board the aircraft) and a viewing device. More complex Ground Stations often include a means to record the received image along with more sophisticated antennas for achieving greater range and clarity.

Aircraft types[edit]

FPV flying wing in flight, captured by the HD camera of another FPV airplane.

Any model aircraft can be modified for FPV. The two most common choices are Fixed Wing aircraft and Multirotors, although early adopters have converted model helicopters.

Fixed wing[edit]

Fixed-wing airframes are generally medium-sized planes with sufficient payload space for the video equipment and large wings capable of supporting the extra weight. By far the most common type of fixed wing aircraft is that with a pusher propeller configuration. This allows for a "prop free" image on either the live video feed or the High Definition recording. Examples of these aircraft include the Multiplex EasyStar, Skywalker 1680 (and subsequent variants thereof), Hobbyking Bixler (and subsequent variants thereof) and Ritewing Zephyr "flying wing" style aircraft. Flying wing designs are popular for FPV, as many pilots believe they provide the best combination of large wing surface area, speed, maneuverability, and gliding ability.

RF Power and Noise[edit]

Think of standing inside a room with many obstacles inside of it, couches, walls, ETC. If you placed a subwoofer in one end of the room, you would find if placed correctly you can hear the subwoofer very clear. The lower frequency tends to find its way across objects and get around obstacles. Now if you try to play some really high pitched music inside the same room at the same volume, you might find you cant hear it as well, or it echoes alot. This is much how radio waves travel. Now if you find the resonant frequncy of the box the speakers are in (for example a tuned antenna) and play the frequency the box is tuned at, you will find that the sound will be much stronger. Now lets say the whole room is full of people. You will find you need more power to hear the speakers. This is where RF power comes into play, you will need more power to punch through the noise before you can hear it again. The misconception that more power means more range is not true. As long as your antennas are properly tuned and resonant, and you have them placed correctly, along with a low noise floor, extreme range is possible. (20 miles has been flown on less than 500MW before) if you live in a very noisy area, such as a city or near towers, more power is needed to get through the noise. But remember that the amount of directivity of your antennas can also help mitigate noise issues if you point the antennas away from the noise.

Antennas[edit]

Antennas are the most important part of the FPV airplane and ground station. Since most 'off the shelf" systems come with a poorly tuned sleeve dipole inside a rubber antenna, range can be greatly reduced and power consumption and heat dissipation greater due to them not being resonant with the transmitter and receiver. this means alot of wasted energy, range, and sometimes funds due to transmitters burning up due to poorly matched antennas. when the FPV Craze first started, Linear antennas were most common. mainly consisting of Biquad, Patch, and Dipole antennas on the ground, and Vee or vertical dipoles on the plane. although these antennas perform excellent, they tend to drop out on sharp turns or climbs since the top and bottom of the antenna has a null zone. in Mid 2010, An electrical Enginneer by the name IBCRAZY, AKA Alex Greve, Redesigned and made popular existing antennas utilizing Circular Polarization, and near perfect radiation patterns with no null zones. Some of the first antennas being the Cloverleaf, Pinwheel, And Madmushroom as common trasmitter antennas, and the Helical, Crosshair, Circular Patch, and Pepperbox being receiver antennas. The antennas produced anywhere from 2DB of gain on the Circular Omnis, and 10-16DB on the Directional Receiver antennas. the antennas could also be mismatched, meaning one could run a Omni on the plane, for example a Skewplanar, and use a pinwheel on the ground, as long as the polarization pattern matched. most antennas are built using these two kinds of polarization; Right Hand Circular Polarization (RHCP) and Left Hand Circular Polarization (LHCP). using this method of polarization mitigates the problem of multipathing which affected linear systems greatly, mainly on 2.4 and 5.8GHZ. Multipathing signals can bounce off buildings, the ground, hills, and water, taking slightly longer than the original signal to get to the receiver from the plane which causes distorted images and reduced range. with these antennas one can also change polarization to reduce interference from other people using the same band and the antennas will reject the opposite polarization signal better than a linear antenna. The most common use for Circular Polarization is on 5.8GHZ,since 5.8 tends to have terrible penetration ability and bounces off objects. with circular polarization and decent antennas, flights as far as 5-10 miles have been made. however circular polarization is most commonly found on Multirotors and the Immersion RC line of fatshark goggles providing short range video contacts with aerial photography rigs. Range is another contributing factor. since lower frequency units such as UHF LRS systems and VHF systems can travel hundreds of miles on low power due to their penetrative capabilities, the higher frequencies used in the FPV scence tend to be more reflective due to their very short wavelength.


Multi-rotor[edit]

Multicopters, especially quadcopters, have fast been gaining popularity as agile camera platforms capable of filming high quality video while hovering and maneuvering in tight spaces. This increase in popularity has come about mainly due to new manufacturing techniques and a reduction in component costs, making this side of the FPV hobby more accessible to a wider audience.

Radio frequencies[edit]

The most common frequencies used for video transmission are: 900 MHz, 1.2 GHz, 2.4 GHz, and 5.8 GHz.[2] Specialized long-range UHF control systems operate at 433 MHz (for amateur radio licensees only — especially with two European nations having exclusive allocations for them, and secondary usage in much of North America) or 869 MHz[2] and are commonly used to achieve greater control range, while the use of directional, high-gain antennas increases video range. Sophisticated setups are capable of achieving a range of 20–30 miles or more. In addition to the standard video frequencies, 1.3 GHz and 2.3 GHz have emerged as the common frequencies get more crowded.[3]

A typical analog FPV video feed with an on-screen display (OSD) readout showing navigation data.

Regulations and safety[edit]

The ability of FPV aircraft to fly far beyond the visual range of the pilot and at significant altitudes above the surface has raised some safety concerns regarding risks of collisions with manned aircraft or danger to persons and property on the ground, causing some national aviation authorities to restrict or prohibit FPV flying.

Despite safety concerns and the somewhat higher risk of crashing at a significant distance from the pilot due to lost video or control links, there has never been a recorded incident of an accident involving an FPV aircraft causing serious injury or damage to property. FPV planes are generally constructed from light foam based materials and thus pose much less risk upon crashing than larger, more powerful aircraft flown by traditional radio-control such as wooden or composite Internal Combustion or Jet Propulsion models. FPV pilots frequently take additional safety measures such as avoiding flying above populated areas or at high altitudes where manned aircraft are likely to be present, and utilizing autopilots with "return to home" capability which automatically fly the aircraft back to the pilot in the event of a signal loss. Such precautions ensure that FPV flights can be undertaken safely and minimize the risk of losing the aircraft or damaging property.

United Kingdom[edit]

The United Kingdom requires that FPV pilots fly with a competent person who is responsible for observing the path of the aircraft for the purposes of collision avoidance and safety, the CAA has recently agreed that this competent person does not have to be capable of flying the aircraft but has been properly briefed by the pilot. The maximum altitude has been raised to 1000 feet (304.8 meters) AGL for aircraft weighing up to 3.5 kg.[4]

United States of America[edit]

In the United States, FPV operations and unmanned aircraft generally may be subject to regulation by the following entities:

Federal Aviation Administration[edit]

The legal status of FPV and model aircraft in general under federal aviation law is currently unclear. In March 2014 in the case Huerta v. Pirker, an administrative law judge with the National Transportation Safety Board (NTSB) dismissed an FAA enforcement action against a model aircraft operator under 14 CFR 91.13 (prohibiting careless and reckless operation of an aircraft), ruling that model aircraft are not legally classified as "aircraft" and that they are not subject to any current Federal Aviation Regulations (FARs).[5] This decision was appealed to the full NTSB. On November 17, 2014 the NTSB issued a ruling reversing the administrative law judge's decision and holding that model aircraft are legally considered "aircraft" at least for the purposes of 14 CFR 91.13, and remanded the case to the administrative judge to determine whether Pirker's actions constituted reckless operation.[6] It remains unclear what other provisions of the Federal Aviation Regulations are applicable to model aircraft, but it is likely that every regulation applicable to "aircraft" generally would potentially apply under this standard.

On June 18, 2014 the Federal Aviation Administration (FAA) issued a notice of interpretation regarding the Special Rule for Model Aircraft in Section 336 of the FAA Modernization and Reform Act passed by Congress in February 2012, which exempted model aircraft meeting certain criteria from future FAA rulemaking.[7] In this document, the FAA stated its position that model aircraft flown using FPV video goggles do not satisfy the definitional requirement in Sec. 336 that model aircraft be "flown within visual line of sight of the person operating the aircraft," and that, "Model aircraft that do not meet these statutory requirements are nonetheless unmanned aircraft, and as such, are subject to all existing FAA regulations, as well as future rulemaking action, and the FAA intends to apply its regulations to such unmanned aircraft."[7] This could potentially subject FPV hobbyists to regulations requiring a pilot's certificate as well as aircraft certification and registration requirements, which are not currently available for unmanned aircraft operators. In the long term, the FAA is developing regulations for small unmanned aircraft systems which may or may not impact FPV flight.

The notice of interpretation further stated that even model aircraft that do qualify for the Sec. 336 exemption are legally considered aircraft, and the FAA has authority to pursue enforcement actions against model aircraft operators who do not comply with certain provisions of Part 91 of the Federal Aviation Regulations, including 14 CFR 91.113, which requires that "vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft." Because the FAA has not yet sought to enforce this regulation against unmanned aircraft operators, whether it applies to model aircraft and what actions are necessary for compliance are currently unknown. However, the FAA has stated numerous times that it does not believe video-piloted unmanned aircraft are capable of "seeing and avoiding" other aircraft as required by this regulation, implying that the FAA views FPV operations as a violation of this regulation and therefore subject to potential enforcement action.

Federal Communications Commission[edit]

There are additional legal implications related to the use of radio frequencies for command and control of FPV aircraft. Licensed amateur radio operators are expressly allowed to use amateur radio frequencies for telecommand of model aircraft. However, the Federal Communications Commission prohibits using amateur radio frequencies for commercial activity (generally any form of economic grain or for-profit activity). The FCC has not yet addressed the issue of creating designated command and control frequencies for commercial unmanned aircraft, and most civilian unmanned aircraft continue to use amateur radio frequencies, even when used for commercial purposes. Though it has not so far pursued any enforcement actions related to use of amateur radio frequencies for commercial unmanned aircraft, the FCC has the authority to levy civil forfeitures and fines into the tens of thousands of dollars for violations of its regulations.

National Park Service[edit]

Under a 2014 edict from the National Park Service, model aircraft and other unmanned aircraft operations are prohibited on all land administered by the National Park Service, with some exceptions for preexisting model aircraft fields that were established prior to the adoption of this rule. Because the National Park Service does not have jurisdiction over airspace, which is exclusively governed by the FAA, this rule only applies to unmanned aircraft flown from National Park Service land. It does not apply to overflight of National Park Service land by unmanned aircraft operated elsewhere.

State and Local Governments[edit]

There are a wide variety of state and local laws and ordinances affecting model aircraft in general and FPV specifically. Many state and local governments restrict or prohibit model aircraft from being flown at local parks. Some state laws purport to restrict or prohibit aerial photography using unmanned aircraft, though such laws would likely be found invalid if challenged in court due to federal preemption, as the FAA has exclusive regulatory jurisdiction over all aircraft and airspace from the surface up. Any laws restricting aerial photography of areas where no reasonable expectation of privacy exists would also likely be vulnerable to challenges under the First Amendment to the United States Constitution.

Academy of Model Aeronautics[edit]

The Academy of Model Aeronautics' (AMA) official Safety Code's rules (which governs flying at AMA affiliated fields) allows FPV flight under the parameters of AMA Document #550, which requires that FPV aircraft be kept within visual line of sight with a spotter maintaining unaided visual contact with the model at all times.[8] Because these restrictions prohibit flying beyond the visual range of the pilot (an ability which many view as the most attractive aspect of FPV), most hobbyists that fly FPV do so outside of regular sanctioned RC clubs' membership and those clubs' flying fields.

Canada[edit]

The Canadian equivalent of the AMA, the MAAC, has similar regulations to that of the AMA for FPV piloting, as part of what is viewable at their organization's documents page.

Australia[edit]

In Australia the operation of FPV aircraft is subject to laws and regulations regarding radio spectrum use which is enforced by the ACMA (Australian Communications and Media Authority) and the use of airspace as enforced by CASA (Civil Aviation Safety Authority).

All unmanned aeronautical activities in Australia are ruled by CASR (Civil Aviation Safety Regulations) Part 101[9] which includes sections for UAV's and model aircraft among other operations. It is currently under review and new regulations specifically relating to UAV's and model aircraft are anticipated.

  • Any commercial use (i.e. any form of payment or benefit) of an unmanned aircraft results in the operations falling under the Unmanned Aerial Vehicle (UAV) Operations Section, CASR 101-1. This section requires formal licensing, training and documentation procedures to be approved and followed. These requirements will typically require an outlay in the order of thousands of dollars which places commercial operations beyond the reach of most hobbyists. This is one area currently under review by CASA with initial reports indicating a potential option of simpler registration for light-weight UAV's without requiring formal certification.
  • Non-commercial use is governed by section 101-3[10] which includes requirements that:
    • No commercial benefit is to be obtained from operating the model – to be flown only for sport or recreational purposes
    • Maximum weight of 150 kg (models over 25 kg must be operated within a club setting under additional conditions)
    • Models under 100 grams are exempt from regulation
    • Only to be flown in daylight unless under written procedures of an authorised organisation (such as the MAAA)
    • The model must remain within continuous direct sight of the operator
    • When within 3 nautical miles of an aerodrome or when within controlled airspace, flight is limited to 400 ft above ground level

Practical considerations[edit]

  • The MAAA (Model Aeronautical Association of Australia) has published a "First Person View (FPV) Policy". In order to comply with the CASR rules they require that the pilot using FPV is not the actual pilot in charge of the model and that a second pilot must have the model in sight at all times, being capable of taking control of the aircraft without any action from the FPV pilot.[11] This has the effect of making the FPV pilot a "guest pilot" for the flight, with all responsibility for the safety and operation of the flight resting with the line-of-sight pilot.
  • While holding an amateur radio license will allow an FPV operator to use transmitter power levels sufficient for flights beyond a few hundred metres, the CASR 101-3 requirement for the model to be in direct sight of the pilot remains a legal stumbling block for the hobby.

FPV ground vehicles[edit]

Any remote-controlled vehicle capable of carrying a small camera and video transmitter can be operated by FPV. Accordingly, FPV systems are also commonly used on remote-control cars and other ground-based models, though the effective range of such setups will typically be much less than a similar aerial system due to ground obstructions blocking the radio signal.

References[edit]

  1. ^ "Personal Bests.". Retrieved 9 September 2012. 
  2. ^ a b c Windestål, David. "The FPV Starting guide". RCExplorer. Retrieved 2 June 2013. 
  3. ^ "FPV Distance Records – By Airframe". RC Groups (forum). Retrieved 14 September 2011. 
  4. ^ "Small Unmanned Aircraft – First Person View (FPV) Flying". Civil Aviation Authority. Retrieved 21 August 2014. 
  5. ^ "Huerta v. Pirker". NTSB Office of Administrative Law Judges. 
  6. ^ "Huerta v. Pirker Decision". National Transportation Safety Board. Retrieved 24 November 2014. 
  7. ^ a b "Interpretation of the Special Rule for Model Aircraft". Federal Aviation Administration. 
  8. ^ "AMA Document #550". Academy of Model Aeronautics. 
  9. ^ http://www.casa.gov.au/scripts/nc.dll?WCMS:STANDARD::pc=PC_91039
  10. ^ http://www.casa.gov.au/wcmswr/_assets/main/rules/1998casr/101/101c03.pdf
  11. ^ http://d1070190-1981.myweb.westnethosting.com.au/maaa/mops/MOP066-Policy-FPVs.pdf