# Solution Draft — Gimbal Camera for High-Altitude Balloon (10km)

## Product Solution Description

A zoom gimbal camera mounted on a balloon at 10km altitude, producing imagery with 10-20 cm/pixel GSD to match an AI detection model trained on 600-1000m altitude data. The system must detect trucks, vehicles, and tracked machinery. Budget: under $30k.

The solution consists of: (1) a zoom gimbal camera with documented serial/TCP control protocol, (2) passive anti-rotation and pendulum damping suspension between the balloon and the camera, (3) a companion computer controlling the gimbal via serial/TCP/MAVLink, and (4) optional computational dehazing to improve image quality through 10km of atmosphere.

```
Balloon (10km)
    │
    ├── Anti-rotation swivel
    │
    ├── Pendulum damper / shock absorber
    │
    └── Camera payload bay (thermally protected)
         ├── Zoom gimbal camera (3-axis stabilized)
         ├── Companion computer (control + image capture)
         └── Power distribution
```

## Existing/Competitor Solutions Analysis

| Solution | Altitude | GSD | Price | Notes |
|---|---|---|---|---|
| UAVOS POD (HAPS) | 15km | 69 cm/pixel | Unknown (>>$30k) | Purpose-built for stratosphere. GSD too coarse for vehicle identification |
| Aerostat systems (SKYSTAR, Hemeria) | 500-3500m | Sub-meter | $28k-500k+ | Lower altitude, includes balloon+winch+camera. Purpose-built but wrong altitude range |
| Military gimbals (WESCAM MX-10) | Any | Sub-cm to m | $100k-500k+ | Best quality but far exceeds budget and has export restrictions |
| DJI Zenmuse H30T | Drone altitude | 5.7 cm @10km | $10,240 | Excellent camera but locked to DJI Matrice drones. Cannot be used on custom balloon platform |

No off-the-shelf solution exists for a $30k camera on a 10km balloon with 10-20cm GSD. All viable approaches use drone gimbal cameras adapted for balloon mounting.

## Architecture

### Component: Zoom Gimbal Camera

| Solution | Sensor / Resolution | Max FL / GSD@10km | FOV@10km | Integration | Additional Sensors | Weight | Price | Fit |
|---|---|---|---|---|---|---|---|---|
| **ViewPro Z40K** | 1/2.3" 25.9MP | ~102mm / 10.3 cm | 606×453m | Serial/TCP, ArduPilot ✅ | AI tracking | ~1kg | $3,000-5,000 | ⭐ Best value — highest resolution for price, largest FOV |
| **A40TR Pro** | 1/2.8" 5MP | 170mm / 11.6 cm | 297×223m | Serial/TCP, ArduPilot ✅ | Thermal + LRF + AI | ~1.5kg | $7,499-7,999 | ⭐ Best multi-sensor — thermal night ops, MIL-STD-810H, tightest pointing |
| **SIYI ZT30** | 1/2.7" 8MP | ~138mm / 12.0 cm | 392×294m | Serial, ArduPilot/PX4 ✅ | Thermal + LRF + wide-angle | ~1.2kg | $6,099-7,309 | Good versatility — 4 sensors, lowest power (9W), wide community support |
| **ViewPro A40 Pro** | 1/2.8" 5MP | 170mm / 11.6 cm | 297×223m | Serial/TCP, ArduPilot ✅ | AI tracking | ~1kg | $2,299 | Budget option — proven 40x zoom, lowest cost, but only 5MP/1080p |
| **Sony α7RV + 400-800mm + T7** | FF 61MP | 800mm / 4.7 cm | 447×298m | Custom integration ⚠️ | None | ~5kg | ~$10,850 | Best image quality — full-frame, best haze resilience, complex integration |
| **Sony RX10 IV + gimbal** | 1" 20MP | 220mm / 11.0 cm | 602×401m | Custom integration ⚠️ | None | ~1.1kg+gimbal | ~$4,200-5,200 | Good sensor quality, wide FOV, but no remote zoom protocol |

### GSD Calculation Reference

```
GSD = (pixel_pitch × altitude) / focal_length

Example for Z40K:
  pixel_pitch = 6.17mm / 5888px = 1.048µm
  GSD = (0.001048mm × 10,000,000mm) / 102mm = 102.7mm ≈ 10.3 cm/pixel
```

### Component: Passive Stabilization System

| Solution | Mechanism | Advantages | Limitations | Cost | Fit |
|---|---|---|---|---|---|
| Anti-rotation swivel + pendulum damper | Mechanical swivel bearing at suspension point, viscous/spring dampers on suspension lines | Proven in aerostat/balloon systems, no power needed, reduces rotation to near-zero | Adds weight (1-3kg), requires custom fabrication | $1,000-3,000 | Recommended baseline |
| Passive pendulum (long suspension line) | Increase distance between balloon and payload (5-10m line) | Simple, reduces oscillation frequency | Doesn't eliminate rotation, adds deployment complexity | $200-500 | Supplement to swivel |
| Reaction wheel (active) | Motorized flywheel counters rotation torque | Eliminates rotation completely | Adds complexity, weight, and power draw | $2,000-5,000 | For demanding pointing requirements |

### Component: Companion Computer Integration

For this project, the existing GPS-Denied system runs on Jetson Orin Nano with MAVLink/MAVSDK. The gimbal camera integration would use the same companion computer architecture:

| Approach | Protocol | Camera Support | Complexity | Fit |
|---|---|---|---|---|
| ArduPilot Lua driver (Viewpro) | Viewlink serial | A40 Pro, Z40K, A40TR Pro | Low — use existing ArduPilot driver | Best for Viewpro cameras |
| MAVLink Gimbal Protocol v2 | MAVLink serial | SIYI, Viewpro (via proxy) | Low-Medium — standard protocol | Best for SIYI cameras |
| Custom serial integration | Manufacturer protocol | Any with serial API | Medium — write custom driver | Fallback for any camera |
| USB/HDMI + Gremsy SDK | USB + CAN | Sony + Gremsy T7 | High — separate camera and gimbal control | Only option for Sony approach |

### Component: Image Preprocessing (Atmospheric Haze Mitigation)

| Solution | Approach | Advantages | Limitations | Cost | Fit |
|---|---|---|---|---|---|
| Dark Channel Prior dehazing | Classic computer vision algorithm | Fast, no training needed, well-proven | May introduce artifacts, struggles with sky regions | Free (OpenCV) | Good baseline |
| CNN-based dehazing (AOD-Net, DehazeFormer) | Deep learning single-image dehazing | Better quality than classical, handles complex haze | Needs GPU, adds latency (~50-100ms) | Free (open source) | Better quality, adds processing time |
| Multi-scale Retinex (MSR) | Contrast enhancement | Simple, fast, improves visibility | Not true dehazing, may amplify noise | Free (OpenCV) | Quick alternative |
| No dehazing (sunny weather) | Direct use | No processing overhead | May reduce AI model accuracy in hazy conditions | Free | Acceptable for clear conditions |

## Recommendations

### Primary Recommendation: ViewPro Z40K ($3,000-5,000)

**Rationale**: Best value proposition for this specific use case.
- 25.9MP resolution — by far the highest among integrated gimbal cameras in this price range
- 10.3 cm/pixel GSD at max zoom — directly matches training data range
- 606×453m FOV — covers the largest ground area per frame, meaning more vehicles visible per image
- 4K video output for live monitoring
- Documented Viewlink serial protocol with existing ArduPilot driver
- ~1kg weight, ~15-25W power
- $3,000-5,000 leaves ample budget for integration, spares, and contingency

**Total estimated system cost**: $5,000-8,000 (camera + passive stabilization + integration hardware)

### Secondary Recommendation: A40TR Pro ($7,499-7,999)

**When to choose instead**: If you need night/thermal operation, laser ranging for target distance, or require MIL-STD-810H environmental certification. The thermal camera enables 24/7 operation and backup detection when optical imagery is degraded.

**Trade-off**: 5MP EO resolution is significantly lower than Z40K's 25.9MP, resulting in 4x smaller ground coverage per frame. For pure AI detection in daylight, Z40K is better.

**Total estimated system cost**: $9,000-12,000

### Alternative: Sony α7RV + FE 400-800mm + Gremsy T7 (~$10,850)

**When to choose**: If atmospheric haze proves too degrading for small-sensor cameras, the full-frame sensor provides significantly better contrast and SNR. This is the "maximum image quality" option.

**Risks**:
- Camera+lens weight (3,140g) is at the Gremsy T7 payload limit (3,175g) — virtually no margin
- No turnkey integration — requires custom camera control, zoom control, and photo trigger
- Sony camera rated 0-40°C only (balloon thermal protection must maintain this range)
- Most complex and heaviest system

**Total estimated system cost**: $13,850-15,850

## Testing Strategy

### Integration / Functional Tests
- Mount camera on test platform, verify serial/TCP control of zoom, pan, tilt, and photo capture
- Verify image capture at different zoom levels and calculate actual GSD against predictions
- Test passive stabilization mock-up with simulated balloon motion (pendulum, rotation)
- Verify power budget under sustained operation (camera + gimbal + companion computer)

### Non-Functional Tests
- Ground-level test: photograph known-size vehicles from maximum available height and verify AI model detection at target GSD (resize images to simulate 10km GSD)
- Atmospheric test: if possible, test from lower altitude (1-2km) and compare image quality with/without dehazing
- Duration test: run camera continuously for 4+ hours to verify thermal stability and reliability
- Balloon integration test: short tethered balloon flight at lower altitude to validate stabilization and control

## References

- NIIRS Civil Reference Guide — https://irp.fas.org/imint/niirs_c/guide.htm
- Atmospheric resolution limit — https://opg.optica.org/josa/abstract.cfm?uri=josa-56-10-1380
- GSD formula — https://support.pix4d.com/hc/en-us/articles/202558849
- Airmobi A40 Pro — https://www.airmobi.com/product/a40-pro-40x-optical-zoom-3-axis-ai-tracking-gimbal-camera/
- ViewPro Z40K — https://www.viewprouav.com/product/z40k-single-4k-hd-25-times-zoom-gimbal-camera.html
- A40TR Pro — https://www.airmobi.com/product/a40tr-pro-40x-eo-ir-lrf-ai-object-tracking-gimbal-camera/
- SIYI ZT30 — https://shop.siyi.biz/products/siyi-zt30
- DJI H30T — https://enterprise.dji.com/zenmuse-h30-series/specs
- LOONG VT500Rs — https://www.loonguav.com/vt500rs
- Sony FE 400-800mm — https://alphauniverse.com/stories/sony-unveils-specialty-400800mm-f6-38-g-oss-super-telephoto-zoom-g-lens/
- Gremsy T7 — https://gremsy.com/gremsy-t7-spec
- Viewpro Viewlink Protocol — https://www.viewprotech.com/index.php?ac=article&at=read&did=510
- ArduPilot Viewpro Driver — https://github.com/ArduPilot/ardupilot/pull/22568
- MAVLink Gimbal Protocol v2 — https://mavlink.io/en/services/gimbal_v2.html
- UAVOS POD — https://uasweekly.com/2026/02/02/uavos-unveils-stratospheric-earth-observation-payload/
- Balloon stabilization — https://iastatedigitalpress.com/ahac/article/5570/galley/5436/view/
- Sony RX10 IV — https://www.bhphotovideo.com/c/product/1361560-REG/
- Foxtech Seeker-30 TR — https://store.foxtech.com/seeker-30-tr-30x-optical-zoom-camera-with-3-axis-gimbal/