An OSD is some equipment that’s not necessary for FPV flying, certainly at the beginner stage. But as you progress can be a very useful tool as your system gets more advanced. There are many many OSD`s available out there, no two are the same, all have lots of features. Some are like flying in a F-16 fighter Jet others are more simple.
Lets breakdown what most display as a standard OSD
Current Sensors :
One of the most common features of an OSD is the current reading feature. This is explained further down the page but a good feature with these is the fact the OSD can run off the power provided by the current sensor. The OSD has output pins in 12 and 5 volts to power your Video Transmitter and FPV Camera also. This is very useful especially for keeping interference down and wiring to an absolute minimum.
Most if not all OSD`s connect via a GPS ( Global Positioning Sensor ) sensor to the Global Positioning Network. They display the GPS coordinates of your plane in real time so you can tell at any point exactly where it is on the planet. As well as the coordinates other values can be obtained by the link to work out the planes height, its direction of flight, its ground speed. These can all be displayed to the pilot via the goggles. In the event of a crash if your recording your flight you can refer to the last know GPS coordinates and find your plane relatively easily with a 3G phone.
Battery Info :
Most if not all OSD units provide flight battery information, some provide video battery information also. The information will consist of battery voltage, current being used in real time and mah of battery used. This is very useful for monitoring when your at your batteries end of capacity and its time to land
Alarms can be set on all OSD units so alert you when user defined values have been breached. Normally by flashing the information to attract attention to itself. You can have alarms for variables such as : Max distance, Max Height, Min height, Battery capacity etc
Home Position :
Some OSD`s have the facility to point to home via a graphic, so if you get lost or just loose your bearings for a brief time an arrow will point to where you are stood so you can return safely
Artificial Horizon :
Some OSD`s but not all are equipped with an artificial horizon. This is a virtual horizon like seen in fighter jets.
Antenna Tracking :
Again some but not all have the facility to transmit telemetry data via an audio channel to your ground station so your antenna tracker can point the antenna straight at the plane to receive the best picture possible
This is a feature that some provide to display your RSSI signal strength. The RSSI signal strength is a voltage produced by the Rc link receiver. The further you fly away the weaker the signal. The OSD displays a percentage of signal giving you an indication of when to turn round
RTH stands for Return To Home, a feature not many have, it can guide the plane if the Rc link is lost back to yourself using various sensors and circle the plane above you to regain control and land.
Here’s a few examples :
This is the EZOSD, made by ImmersionRC its available for around £150. Not the cheapest of OSD`s available but one of the best. Many features including antenna tracking and live telemetry. Its a very simple uncluttered system that’s very popular with flyer’s. The one great feature with this system is when coupled up with immersion video transmitters that everything is plug and play. No soldering or guess work its all done for you.
Hornet OSD with FY31AP
This OSD comes with the usual features of most OSD`s with the added features of being plug and play with its own Auto Pilot system. The Auto Pilot will interact with the OSD and the OSD will display the Auto Pilots state so you know exactly what mode you are in. This system will not only monitor your essentials such as lipo state, GPS quality, Current being used, but will also stabilize your plane, circle a spot you pick and return your plane to you if you have any problems or run out of RC range.
The Blackstork II is a more budget orientated OSD, it has basic features but doesn’t support antenna tracking, telemetry or RTH. For basic information display needs it will do the job. Its display is easy to see, outlines fonts so sticks out what ever the background footage. It is a no frills unit, but as an entry level option, could be worth considering.
The RVOSD is a feature packed OSD as you can see from the screen shot a wealth of information is displayed as well as artificial horizon. Some prefer not so much of a cluttered screen though which can spoil the view. As with most OSD choices the decision is personal.The generation 5 is now available which like the FY31AP uses gyros, accelerometers and GPS to stabilize the plane and return to home. A multitude of screens to choose from and very user friendly. Its a very capable unit.