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GEMS Drone Control Over Fiber Solution
1. Solution Overview
GEMS Navigation provides advanced fiber optic solutions for drones. Based on Radio over Fiber (RoF) technology, the DOF solution carries the complete radio link of a drone remote controller over optical fiber, extending reliable command and control from the ground control station to a remote site more than 50 km away — beyond RF line-of-sight limits and immune to electromagnetic interference.
Solution highlights:
- Transparent RF-over-fiber link — works with any drone technology and any remote controller, no protocol conversion required
- Wide frequency coverage — 50–2800 MHz, covering mainstream RC control and video transmission bands
- Long distance — optical transmission distance greater than 50 km
- Outdoor ready — IP67 waterproof housing with built-in temperature control module
- Flexible power — 12 V DC standard; 48 V DC / 220 VAC optional
2. How It Works
Radio over Fiber (RoF) technology transmits high-frequency RF signals over optical fiber cables instead of traditional coaxial cables or wireless links, leveraging the low loss, high bandwidth and electromagnetic interference immunity of optical fiber.
In the DOF solution, the A Unit (Local Unit) is installed at the ground control station together with the drone remote controller, and the B Unit (Remote Unit) is installed at the remote flight site together with its antennas. RF signals between the remote controller and the drone are converted into light, carried over the optical fiber, and re-radiated by the B Unit antennas next to the drone. The drone sees a completely normal radio link, while the pilot gains fiber-grade distance and stability.
The optical link between the A Unit and the B Unit uses round FC-APC fiber connectors.
3. Two Deployment Options
The DOF system supports two coupling methods between the remote controller and the A Unit: wireless coupling and wired coupling. Both options use the same hardware pair (DOF-A Unit + DOF-B Unit) and deliver the same fiber link performance — the difference is only in how the remote controller connects to the local A Unit.
3.1 Option 1 — Wireless Coupling
The remote controller keeps its original antennas and is simply placed near the A Unit at the ground control station. The RF signal is coupled over the air between the controller's antennas and the antennas of the A Unit, then transmitted over fiber to the remote B Unit. No modification to the remote controller is required — deploy in minutes, ideal for quick setup, mobile operations and field trials.
3.2 Option 2 — Wired Coupling (DOF-AB-WIRE)
The remote controller is connected by RF cable directly to the N-female antenna ports of the A Unit, replacing the controller's original antennas. The RF path from the controller to the A Unit becomes fully deterministic — no over-the-air path loss, no coupling alignment. Ideal for fixed ground control stations and long-duration missions that demand maximum link stability.
4. Wireless vs. Wired Coupling — Comparison
| Aspect | Wireless Coupling | Wired Coupling |
|---|---|---|
| Controller-to-A-Unit connection | Over the air, between the controller's own antennas and the A Unit antennas | RF cable connected directly to the A Unit N-female antenna ports |
| Modification to remote controller | None — controller used exactly as delivered | Controller antennas replaced by RF cable to the A Unit |
| Installation effort | Minimal — place the A Unit near the controller and power on | Requires RF cable routing between controller and A Unit |
| RF path stability | Depends on over-the-air coupling between antennas | Deterministic wired path, no coupling alignment needed |
| Recommended use | Quick deployment, mobile ground stations, field trials, demo and training | Fixed ground control stations, long-duration missions, interference-sensitive sites |
| Drone side (B Unit) | Identical in both options — installed at the remote site, antennas facing the drone | Identical in both options — installed at the remote site, antennas facing the drone |
5. Key Benefits
- Reliable long-distance communication — optical transmission distance greater than 50 km
- Extended operational range — break through the RF line-of-sight limit of conventional radio control
- Universal compatibility — works with any drone technology; transparent to existing RC systems
- Drone over Fiber (DOF) — DOF belongs to the RoF (Radio over Fiber) product family; the same fiber infrastructure can also carry GNSS/GPS signals
- Low latency — optical delay of only about 5 ns per meter of fiber, real-time control response
- All-weather operation — IP67 waterproof housing with temperature control module keeps the unit working in extreme heat and cold
6. Technical Specifications
| Parameter | Specification |
|---|---|
| Frequency range | 50–2800 MHz |
| Impedance | 50 Ω (input and all output ports) |
| Gain (up link / down link, TX+RX) | ≤ 43 dB |
| RF output power | ≤ 33 dBm standard / 35 dBm max (B Unit, up link); ≤ 0 dBm nominal (A Unit, down link, adjustable −10 to +10 dBm) |
| RF input power | +36 dBm max damage level (A Unit, up link), recommended operating range +20 to +33 dBm; ≤ +10 dBm (B Unit, down link) |
| Isolation (A / B Unit, input to output) | ≥ 25 dB (typical 30 dB, max 40 dB) |
| Input / output VSWR | ≤ 2.0 : 1 |
| Noise figure | ≤ 6 dB (TX+RX) |
| Pass band ripple | ≤ 3 dB |
| RF connectors | N female (antenna ports and RF ports) |
| Optical fiber connector | Round FC-APC |
| Optical wavelength (TX / RX) | A Unit: TX 1270 nm / RX 1330 nm B Unit: TX 1330 nm / RX 1270 nm |
| Optical output power | ≤ 7 dBm (TX) |
| Optical receiving sensitivity | ≤ −30 dBm |
| Light delay | Approx. 5 ns per meter of fiber |
| Optical transmission distance | Greater than 50 km |
| Power supply | 12 V DC standard (48 V DC / 220 VAC optional) |
| Power consumption | ≤ 18 W (12 V DC, 1.5 A) |
| Waterproof grade | IP67 |
| Operating temperature | −20 °C to +65 °C |
| Storage temperature | −30 °C to +80 °C |
| Unit dimensions | 180 × 173 × 60 mm (D × W × H) |
7. Typical Applications
- Beyond-visual-line-of-sight (BVLOS) inspection of power lines, pipelines, bridges and solar farms
- Tower-top and rooftop drone docking stations ("drone in a box")
- Border, coastal and perimeter security patrol
- Precision agriculture over large-scale farmland
- Flight test ranges and pilot training fields
- Emergency response and temporary communication relay
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Shenzhen (Headquarters)
Tel:(86)755-29644311
Fax:(86)755-29644383
Email: sales@gemsnav.com
Add: F2,Building 6, RunDongSheng Industry Park, Baoan District, Shenzhen, China
Amy Wu /Sales Manager
Nancy Liang/Sales
ZHENG, GUOHUI/Technical support