BRB Lora Overview

System Overview

High-power rocket telemetry has two main challenges: maintaining reliable long-range communications and operating in an RF environment where dozens of transmitters may be active at the same time. Traditional single-channel systems, or packet systems without synchronization, tend to suffer from packet collisions and receiver congestion as the number of transmitters increases.

The BigRedBee LoRa GPS tracking system was designed specifically for these conditions. By coordinating both time and frequency, it allows many trackers to operate simultaneously while maintaining reliable long-range communications.

Timing and Synchronization

Every transmitter and receiver uses the GPS pulse-per-second (PPS) signal as a common time reference. Because all units are synchronized to GPS time, they remain aligned without accumulating clock drift. This provides a stable timing reference that allows all communication events to occur at precisely scheduled times.

Frequency Hopping

Rather than transmitting on a fixed frequency, the system uses a pseudo-random frequency-hopping sequence. Both the transmitter and receiver independently calculate the same hop sequence from shared parameters and GPS time, so no coordination messages are required.

Since the receiver always knows which frequency should be active at any moment, it can switch directly to the correct channel instead of scanning continuously. This reduces acquisition time and improves reliability.

Time Slots

The system also divides each one-second interval into multiple transmission time slots. Each tracker transmits only during its assigned slot, greatly reducing the chance that two transmitters will interfere with one another. This becomes especially important at large launches where many trackers are operating simultaneously.

Frequency Bands

The system is available for both the 900 MHz ISM band and the 70 cm amateur radio band. The 70 cm version gives licensed amateur radio operators an alternative when the 900 MHz band becomes crowded, providing additional flexibility for launches with heavy RF activity.

Result

By combining GPS synchronization, deterministic frequency hopping, and scheduled transmission time slots, the BigRedBee telemetry system continues to operate reliably even as the number of active transmitters grows. Instead of relying on higher transmit power or a single operating channel, the system reduces interference through careful coordination of when and where each transmission occurs. This approach provides dependable long-range telemetry under the RF conditions commonly encountered at large rocket launches.