Skyroot Aerospace vs. Agnikul Cosmos: Launch Vehicle Telemetry and Avionics Software Stacks

Real-Time Embedded Systems: Guidance, Navigation, and Control (GNC)

Avionics systems in orbital launch vehicles (such as Skyroot's Vikram series and Agnikul's Agnibaan) require hard real-time operating systems (RTOS) to manage guidance, navigation, and control (GNC) loops. A GNC algorithm must query inertial measurement units (IMUs), parse GPS/NavIC coordinates, compute thrust vector control (TVC) nozzle actuator positions, and command cold-gas thrusters. These tasks operate on strict scheduler deadlines (typically sub-millisecond loops).

Both aerospace startups leverage redundant microcontroller boards running FreeRTOS or proprietary RTOS solutions. The avionics stack is written in C and C++, compiled with strict optimization levels, and verified using static analysis and hardware-in-the-loop (HIL) simulation. A hardware-level watchdog timer resets the system if a flight computer crashes, instantly failing over to a backup secondary flight system.

Radio Frequency (RF) Downlink and Telemetry Packets

During launch, rocket telemetry must be downlinked in real-time to ground telemetry tracking stations. Bandwidth is constrained by RF propagation limits, usually utilizing S-band frequencies. Avionics systems packetize data into structures consisting of timestamp offsets, sensor values, actuator telemetry, and error correction headers.

Packet payload sizes are highly optimized. Instead of transmitting raw 32-bit floats for every temperature sensor, values are scaled and converted into 10-bit or 12-bit integers. Telemetry data are structured according to CCSDS (Consultative Committee for Space Data Systems) guidelines. Redundancy is built-in; flight computers store high-frequency datasets on internal black-box flash systems to recover flight logs in case of mission anomalies.

Ground Control Data Engineering

On the ground, RF telemetry streams are demodulated, decrypted, and parsed by ground-station software. The parsed stream is routed to high-speed data buses. Ground control software uses time-series databases (like InfluxDB) or columnar analytic databases (like ClickHouse) to handle high-frequency data ingest (often exceeding 50,000 data points per second).

Ground controllers monitor Grafana dashboards displaying trajectory errors, rocket chamber pressure, nozzle temperature, and battery charge states. If variables drift from pre-launch flight limits, automated alerting systems trigger warning flags on flight controllers' consoles.

Avionics Telemetry Packet Structure (C Code)

Hardware-in-the-Loop (HIL) Flight Simulation Testing

Before launching a rocket, aerospace engineers must validate guidance, navigation, and control algorithms in environments that mimic flight conditions. Hardware-in-the-loop (HIL) simulation connects the physical flight computer and actuator controller to a real-time simulator. This system injects simulated sensor inputs (IMU rates, NavIC coordinates, aerodynamic pressures) and captures the computer's actuator commands to evaluate flight trajectories.

Skyroot Aerospace runs HIL tests using dedicated real-time simulators running flight models compiled in MATLAB/Simulink. Flight telemetry interfaces are tested for data dropouts and signal jitter. Agnikul Cosmos integrates HIL testing with its custom 3D-printed engine testing loops. This enables engineers to validate throttle control valves under closed-loop pressure feedback. HIL testing minimizes the risk of software regressions during real launches.

Core Takeaways for Product Teams

Building high-scale software applications in India requires a deep understanding of local constraints, high latency networks, and rapid regulatory updates. Product managers and engineering leads must prioritize structural data integrity, strict audit logs for compliance, and telemetry monitoring at the edge. By designing architectures that balance user experience with regulatory requirements, platforms can successfully minimize churn, optimize transaction success rates, and build robust technology stacks that support sustainable growth in India's competitive digital economy. Keeping stacks aligned with RBI and government portals is no longer optional; it is the core foundation of product engineering.