Satellite Surveillance Systems for Real-Time RF Intelligence Collection

How Teledyne SP Devices’ High-Speed Digitization and Edge Processing Enable Scalable Monitoring of Satellite Signals Across Multiple Frequency Bands

Satellite monitoring provides continuous observation of satellite communications and navigation signals to ensure link quality, detect interference, and verify compliance with spectrum regulations. These systems offer a comprehensive and consistent view of uplink and downlink behavior, which is essential for applications ranging from GNSS integrity and spectrum monitoring to interference detection and system validation.

Surveillance Objectives and System Architecture

The primary goal of satellite monitoring is to maintain the integrity of space-to-ground and ground-to-space links. This includes verifying the quality of uplinks and downlinks, detecting unintentional or malicious interference, and supporting regulatory compliance.

From an architectural perspective, surveillance systems are generally structured around three elements:

1. Space segment: satellites equipped with transponders and antennas operating in defined frequency bands.
2. Ground segment: monitoring stations equipped with large antennas, RF front-ends, and digitizers.
3. User segment: specialized software and hardware for analyzing and visualizing captured data.

Frequency Bands and Sampling Considerations

Satellite services operate on designated radio frequency bands, each divided into uplink and downlink sub-bands in bidirectional systems to minimize mutual interference. Downlinks are typically allocated to the lower portion of a band due to lower atmospheric attenuation, while uplinks occupy higher frequencies to support higher data rates. Sub-band definitions vary by system; for example, Galileo uses “E” designations in the L band rather than the “L” nomenclature used by other GNSS constellations.

From a monitoring perspective, this diversity makes frequency planning and sampling strategy crucial. The sampling rate must ensure that the useful signal occupies a single Nyquist zone, with out-of-band components removed by analog filtering. For direct sampling, this typically translates to minimum rates of approximately:

• 2 GSPS for the L band
• 4 GSPS for the S band
• 8 GSPS for the C band
  assuming appropriate band-pass filtering.

Front-End Digitization and Signal Capture

Modern monitoring stations rely on wideband digitizers to convert analog RF signals into digital data streams. Devices such as the Teledyne SP Devices ADQ35-WB support direct sampling of L and S band signals without frequency mixers, reducing system complexity and calibration effort. With 12-bit resolution and a usable input bandwidth of up to 9 GHz, these digitizers enable flexible deployment across multiple satellite bands. External low-noise amplifiers and anti-aliasing filters remain essential to preserve signal fidelity and prevent spectral folding during analog-to-digital conversion.

The choice of sampling rate has a direct impact on data integrity and downstream processing efficiency. For example:

• Sampling the L band at 5 GSPS fully places the signal within the first Nyquist zone.
• Undersampling the S band at 4 GSPS confines the signal within the second Nyquist zone with sufficient guard bands.

Incorrect rates may split the signal across Nyquist boundaries, introducing unavoidable spectral folding.

FPGA Preprocessing and Data Reduction

Raw data rates from wideband digitizers can exceed practical transfer and storage limits. At 10 billion samples per second and 2 bytes per sample, a single channel generates roughly 20 GB/s. To manage this volume, embedded FPGA processing is used to reduce data rates before transfer over PCIe links.

Two approaches are particularly relevant for satellite monitoring:

1. Binary compression: reduces the number of bits per sample, allowing continuous streaming within PCIe bandwidth limits while preserving full-band information.
2. Digital downconversion: implemented using oscillators, filters, and numerically controlled decimation stages on FPGAs, translating selected RF channels to baseband or intermediate frequencies. This both reduces data rates and improves signal-to-noise ratio through coherent filtering and processing.

High-Speed Data Transfer and GPU Processing

For real-time or near-real-time analysis, PCIe-based architectures are preferred. Peer-to-peer data transfer enables digitizers to send data directly to GPUs via DMA, bypassing the host CPU and system memory. This minimizes latency and allows aggregate data rates approaching PCIe Gen5 limits, supporting simultaneous streams from multiple digitizers.

GPUs complement FPGA processing by handling computationally intensive but less latency-critical tasks, such as channelization, demodulation, and long-term statistical analysis. For example, extracting individual Galileo sub-bands from a wideband L-band capture can reduce hundreds of MHz of spectrum to a few gigabytes per second, well within the capabilities of modern GPUs.

High-Speed Recording and Storage Strategies

When long-duration recordings are required, storage bandwidth can become a limiting factor. RAID configurations using NVMe SSDs connected via PCIe cards allow parallel writes across multiple drives. Enterprise-class SSDs maintain sustained write speeds over long periods, supporting cumulative recording rates of tens of GB/s and total capacities at the petabyte scale per site. Consumer-grade drives remain suitable for shorter captures but experience throughput degradation once internal SLC caches are exhausted.

Relevance for Modern Satellite Monitoring

By combining wideband digitization, FPGA-based preprocessing, GPU acceleration, and scalable PCIe storage, modern satellite monitoring systems provide a cost-effective and flexible foundation for RF intelligence collection. This architecture supports evolving requirements such as multi-band monitoring, real-time interference detection, and large-scale data capture, making it suitable for both operational monitoring networks and research-focused measurement campaigns.

Glossary

Source: Teledyne SP Devices

January 26, 2026