Interactive VOR Navigation Simulator
How does a VOR receiver show an aircraft's position relative to a selected course? This free interactive simulator lets you explore VOR radials, OBS course selection, CDI needle movement, and TO/FROM indications as the aircraft moves around a ground station.
Compare two classic VOR displays, a horizontal situation indicator (HSI), and a radio magnetic indicator (RMI). Observe inbound and outbound navigation, course interception, station passage, and wind effects. The simulator also illustrates reverse sensing on conventional VOR indicators; the HSI uses a different course presentation.
VOR Navigation Simulator
Move the aircraft, select a VOR course with the OBS, and fly different headings. Compare two conventional VOR needle styles (sliding and pivoting), an HSI, and the VOR bearing needle of an RMI. All four displays follow the same aircraft.
Drag the aircraft or click a position. Orange shows the radial FROM the station; blue shows the OBS course. Thin red dashed lines mark ±10° from the OBS course, where a conventional VOR CDI reaches full scale. At shorter VOR distances, the same lateral offset produces a larger angle. Try Fly in Intercept to see the needle cross center gradually.
* Map distance is calculated from aircraft position for teaching purposes; a basic VOR receiver does not measure distance. Magnetic bearings are idealized. The RMI displays only its VOR pointer; an ADF source is not modeled. Signal loss, NAV/HDG failures and reception limits are not simulated. The TO/FROM transition width and station-passage uncertainty are illustrative, not equipment-calibrated. For ground study only — not for navigation.
Comparing the Four VOR Instruments
The same aircraft position can look very different on cockpit navigation instruments. This simulator displays two conventional VOR indicators, an HSI, and an RMI together so you can compare what each one shows as the aircraft moves or the pilot changes the OBS and heading.
Classic VOR: Two Needle Styles
The two classic VOR indicators use different mechanical-looking presentations: one needle pivots, while the other slides sideways. With the same OBS setting and aircraft position, both show the same left/right course deviation and TO/FROM information. Compare how each needle moves as you change the selected course.
HSI: Course and Heading Together
The horizontal situation indicator (HSI) combines a heading compass card with the selected course and its deviation. Change the aircraft's heading while keeping the OBS unchanged: the course symbol changes its orientation relative to the airplane. The HSI gives a heading-referenced picture rather than a fixed-face needle presentation.
RMI: Bearing to the Station
The radio magnetic indicator (RMI) uses a pointer to show the bearing toward the tuned VOR station against a heading compass card. Unlike a CDI, it does not show deviation from an OBS course. Try changing only the OBS: the RMI bearing does not change. Then change the heading and observe the pointer's new position relative to the aircraft's nose.
What Should You Compare in the Six Scenarios?
In Track inbound, Track outbound, and Intercept, compare the two CDI presentations with the HSI course display. At the same time, notice that the RMI answers a different question: where is the station relative to the airplane's heading?
In Reverse sensing, compare conventional CDI interpretation with the heading-referenced HSI presentation. In Crosswind tracking, compare the aircraft's heading with its actual movement across the map. During Station passage, the simulator briefly blanks close-in indications for clarity; real VOR indications may fluctuate instead, and their behavior depends on conditions and equipment.
VOR Instrument Simulator: Key Questions
Why do the two classic VOR needles move differently?
This simulator includes two conventional VOR presentations. One needle pivots around a point, while the other slides left or right. They represent the same course deviation for the same OBS setting and aircraft position. The difference is how the indication is drawn, not a different radial or a different navigation signal.
Why does the HSI change when I turn the aircraft without moving it?
The HSI includes a heading-referenced compass card. When you change the heading, the selected course appears at a different angle relative to the aircraft symbol. If the aircraft's position and OBS setting remain unchanged, the VOR course deviation itself does not change merely because you turned the aircraft.
Why does changing the OBS not move the RMI bearing pointer?
An RMI bearing pointer indicates the direction of the tuned VOR station relative to the aircraft's heading. It is not controlled by the OBS course selection. With position and heading unchanged, rotating the OBS does not change the RMI pointer. Changing the heading changes the pointer's position relative to the aircraft symbol; moving the aircraft can change the bearing itself.
Does the HSI have the same reverse-sensing presentation as a classic VOR?
A conventional VOR CDI can be misinterpreted when the OBS is set for the opposite direction from the course the pilot intends to fly. The HSI presents the selected course in relation to the aircraft's heading, making its orientation easier to see. It does not automatically choose the correct course. The simulator's reverse-sensing scenario is intended to highlight this difference in interpretation.
Why do the simulator needles disappear near the station?
The simulator uses a simplified close-in area where it blanks some indications to represent station-passage uncertainty. In a real airplane, indications may fluctuate rather than simply disappear. The behavior depends on geometry, altitude, signal reception, and the installed equipment. The simulated area is not an actual VOR coverage or accuracy limit.
