Multi-Vehicle GPRS Tracking System

I want to build a turnkey GPRS-based tracking solution for a small fleet of up to ten vehicles. The platform must stream each vehicle’s live GPS position, keep a searchable log of every route taken, raise instant geofencing alerts, and give me remote engine-cut capability together with reliable petrol-level monitoring.

Hardware
• A compact on-board unit that pairs a high-sensitivity GPS receiver with a quad-band GSM/GPRS modem.
• Wired inputs for ignition status, fuel-level sensor and an output relay for safe engine cut-off.
• Over-the-air firmware update support so I never have to recall a device for basic fixes or tweaks.

Firmware & Protocol
The device should package GPS, fuel and status data in efficient binary or JSON packets and push them to my server over GPRS at configurable intervals (default 10 s when moving, 60 s when idle). MQTT or a lightweight TCP protocol is preferred for low latency. Downlink commands must allow engine cut/restore, geofence table updates and sampling-rate changes.

Server & Interface
A cloud-hosted backend (Node.js, Python or PHP with MySQL/PostgreSQL) will ingest the data, persist it and expose REST/WebSocket endpoints to a responsive web dashboard and an Android/iOS app. The interface should:
• Render live positions on Google Maps/OpenStreetMap.
• Replay any day’s route with speed and stoppage markers.
• Let me draw circular or polygon geofences and set per-fence SMS/email/push alerts.
• Show real-time fuel level and trend reports.

Acceptance criteria
1. Live location latency under 5 s on a 3G connection.
2. Engine cut/restore executes within 10 s of command.
3. Fuel readings accurate to ±5 %.
4. Geofence alerts delivered within 10 s of breach.
5. Full-day route history retrievable in under 3 s.

Please include schematics, BOM, Gerber files, compiled firmware, server source code, and installation documentation so production and deployment are straightforward.