First person view
First Person View ( English first person view , freely translated: view from the first person perspective '; abbreviated FPV) describes a variant of the RC model building in which the model using camera technology from the perspective of the remote-controlled model, as from the perspective of a driver / Pilot is controlled. FPV can be used on all types of RC models, but also on commercial and military drones . Most often, FPV is used in model aircraft such as quadrocopters or normal model airplanes. In these cases one speaks of camera flight or immersion flight.
Depending on the state, the use of FPV-controlled models may be subject to legal restrictions.
Passive FPV
In this variant, a camera is installed on the model that records a film on a data storage device . So you can then look at the journey or the flight from a first- person perspective . The technical effort for passive FPV is very manageable, because all that is required is a camera that stores the video sequences. Due to the development of surveillance technology, a large selection of ever smaller cameras and signal components is available that require little space in the model and have both low weight and low energy consumption.
Active FPV
The first-person perspective (FPV) is achieved here by a camera (mostly built into the cockpit of the RC model). The signals from the on-board camera are sent to the RC pilot via a transmitter to a receiver . Here the signal is converted again and the images from the camera are displayed in real time on a screen (e.g. notebook or video glasses ). The transmission is almost always analog and takes place so quickly that a delay is imperceptible to the pilot. This creates the impression of being a pilot on the plane ; you control the model directly. As a refinement, swiveling cameras are used that z. T. can be controlled directly via the head movements of the pilot, so that the immersion is even more complete.
The following components are required for active FPV:
FPV camera: When choosing the FPV camera, make sure that the image from the camera copes well with the lighting conditions. This is particularly important in the case of flight models, as a brief loss of view at great speed and distance can quickly lead to the model crashing. In practice, certain analog cameras from the surveillance camera sector have proven their worth. Because of their faster brightness compensation , CCD cameras are better suited for the FPV hobby than those with CMOS sensors. However, small commercially available video cameras are used that have a liveout output and can simultaneously record videos and send a live image to the radio transmitter. Suitable for this is z. B. a GoPro .
- Video transmitter in the model and video receiver on the ground: When selecting a video transmitter and receiver, the range of the transmission of the video signal must be taken into account, as it determines the possible range of the model from the pilot. According to the current state of technology, transmission is almost always analogue. The range of analog video transmitters is limited in Germany and Austria by the permitted output of 10 mW for 2.4 GHz systems and 25 mW for 5.8 GHz systems. The choice of antennas is just as important as the radio range. Directional antennas can significantly increase the range.
Antenna : Due to the power limitation of the transmitter, the range can only be extended by choosing the optimal antenna. Linearly polarized antennas can be used for cars, ships and multicopters. In the case of airplanes, the model and the ground station are better equipped with circularly polarized antennas. This allows the aircraft to fly loops and rolls without the radio signal weakening. Linear antennas must always be aligned parallel to one another, otherwise the signal will be significantly attenuated. In addition, circular antennas do not have the problem of multipathing (reflections of the signal and their different propagation times, which leads to greatly reduced ranges).
- Screen (e.g. notebook or video glasses): What is important for screens is a low latency (particularly problematic with notebooks) and a high tolerance to noise (no blue screen). However, video glasses are recommended.
Optional components are
- Pan / tilt technology for the camera
- Head Tracker : Optional you can get a head tracker (dt head tracking.) Use. This registers the movements of the head and tracks the camera in the model with the help of servos (pan / tilt technology). If the pilot looks to the left while standing on the ground, the model's camera also pans to the left. This makes the FPV experience even more realistic.
- On-screen display : By installing additional sensors and GPS receivers, altitude, distance to the pilot, speed, battery voltage, artificial horizon and the direction to the pilot can be displayed in the transmitted image using the OSD (on-screen display). These data are an important support when controlling the model, as orientation is difficult due to the limited view and the lack of spatial perspective makes it difficult to estimate height and distance. Furthermore, the pilot can hardly rely on his or her orientation experience, since he perceives the spatial environment from a completely new perspective.
- Telemetry : In addition to the display in the OSD, modern high-quality radio remote controls offer the possibility of important measurement data such as battery voltage, flight altitude and much more. via a return channel on the display of the remote control. By specifying minimum values (e.g. battery voltage), an alarm can be triggered that informs the pilot about the remaining capacity of the battery so that a flight model can land before an impending crash. The use of telemetry is possible with various systems, e.g. Sometimes even with the inclusion of smartphones and specially developed apps that can even record the flight route and then display it on a map.
- Gyroscope- based stabilization systems for model aircraft. These are most commonly used to stabilize the aircraft for quieter aerial photography.
- Return-to-home : A return-to-home function has now been built into some of these systems, which automatically flies an aircraft back to the previously determined take-off location, for example in the event of a problem.
- Antenna tracker : An antenna tracking system can be used to track directional antennas, which tracks the directional antenna to the model and thus offers the FPV pilot a greater radius of action. For this purpose, the position data sent back by the aircraft are evaluated and the antenna is aligned accordingly to the aircraft via a stepper motor.
FPV frequencies
1.3 GHz band: 1080, 1120, 1160, 1200MHz
2.4 GHz band: 2370, 2390, 2410, 2430, 2450, 2470 , 2490, 2510MHz
3.3 GHz band: 3310, 3320, 3330, 3345, 3355, 3370, 3380, 3395, 3405, 3420, 3430, 3445, 3455, 3470, 3480, 3495MHz
5.8 GHz band:
- 5645, 5658, 5665, 5685, 5695, 5705MHz
- 5725, 5732, 5733, 5740, 5745, 5752, 5760, 5765, 5769, 5771, 5780, 5785, 5790, 5800, 5805, 5806, 5809, 5820, 5825, 5828, 5840, 5843, 5845, 5847, 5860, 5865, 5866 MHz
- 5880, 5885, 5905, 5917, 5925, 5945 MHz
According to the manufacturer, these frequency specifications are for international use. The TV transmitter usually generates 25 mW. But there are also amplifiers up to 2 watts. In Germany, the 1.3 and 3.3 GHz bands are not allowed at all. The frequencies legal in Germany are limited to 2400–2483 MHz and 5725–5875 MHz, marked in bold in the table . The maximum transmission power is 2.4 GHz at 10 mW and 5.8 GHz at 25 mW.
Legal guidelines
Germany
With the amendment to the air traffic regulations of March 30, 2017, the operation of unmanned aviation devices with the help of video glasses or another visual output device was explicitly regulated in Section 21b for the first time. After that, an FPV flight is generally permitted and is not counted as being out of sight of the driver. Up to a take-off mass of 250 g, an altitude of 30 m must not be exceeded. If the weight exceeds 250 g, another person must also have the aircraft in sight at all times and observe the airspace so that the controller can be informed of any immediate dangers.
United States
The Federal Aviation Administration issued a guideline for the first time restrictions on its use in June 2014 . Airworthy models for private leisure activities must therefore weigh less than 25 kg and be visible to the pilot during use without the use of aids. Control by “First Person View” is so severely restricted because the authorities consider the pilot's field of vision to be too limited and classify the risk of an accident as correspondingly higher.
Switzerland
From mid-2020, Switzerland will be based on the EU guidelines for flying drones. Flying with video glasses is only permitted if someone with direct visual contact with the drone can intervene at any time, as is the case with the FPV drone races. Otherwise, authorization from the FOCA is required. Without direct visual contact, there is a high risk that I could collide with another aircraft whose pilot does not see my drone either. Flying drones out of sight is not permitted without a permit. The FOCA regulates the approval process.
Web links
- Press article: DMFV Competence Unit FPV positions itself
- X-ray image of an FPV model airplane and ground station
Individual evidence
- ↑ Federal Network Agency. (PDF; 48 kB) Accessed April 24, 2019 .
- ↑ "US aviation authority clarifies model aircraft laws" BBC June 30, 2014, viewed June 30, 2014
- ^ Federal Office of Civil Aviation FOCA: Rules and general questions about drones. Retrieved May 2, 2020 .