NetSim Astra

3D globe visualization

Interactive CesiumJS globe with satellite orbits, ground markers, heatmap overlays, and footprint polygons, with playback for time-series results.

Link budget analysis

Full link budget: EIRP, free space path loss, antenna pattern gain, clutter, polarization, and ITU-R P.618 atmospheric losses.

Coverage prediction

Animated coverage heatmaps over a region at configurable grid resolution. Click any point for a full link-budget breakdown.

Point & footprint

Track received power at a fixed location over time, and map per-satellite coverage footprints from an Rx-power threshold.

Walker constellation

Generate Walker Delta or Star constellations with configurable planes, satellites per plane, altitude, and inclination. Scale to 100 planes, 360 satellites per plane, and altitudes up to 36,000 km, from LEO to GEO.

Real satellites (TLE)

Track Starlink, OneWeb, GPS and more using live TLE data from CelesTrak or N2YO, with a configurable polling interval.

Single fixed satellite

Place a stationary satellite at any position for antenna-pattern testing and deterministic, single-timestep coverage analysis.

Geostationary orbits

Analyze GEO and inclined geosynchronous satellites by manual entry, presets (INSAT/GSAT), or live TLEs. GEO adds multibeam CINR.

Received power

• EIRP, receive gain, and antenna pattern gain at the off-axis angle
• Free space path loss, clutter, polarization, and additional losses
• Click any heatmap point for the full breakdown

RF parameters

• TX power, antenna gain, EIRP, RX gain, system margin
• Bands: L, S, X, Ku, K, Ka, Q/V
• Additional losses and polarization loss

Antenna pattern models

• Gaussian: simplified analytical model
• Bessel (3GPP TR 38.811): circular aperture
• ITU-R S.672-4: FSS reference pattern
• Phased array (URA): beam shaping for 5G NTN
• Custom: imported CSV or Ansys HFSS FFD patterns

ITU-R P.618 propagation

• Rain fade and gaseous absorption
• Cloud attenuation and tropospheric scintillation
• Link availability via exceedance conversion

Clutter loss

• Terrain attenuation from ESA WorldCover land classes
• Defaults from 0.5 dB over water to 8 dB in built-up areas
• Per-class values and fallback editable, saved with the project
• Applied per ground point in coverage grids

Off-axis & elevation

• Antenna gain evaluated at the true off-axis angle
• Minimum elevation mask for visibility
• Slant range and geometry from satellite position

Imported patterns

• CSV gain tables over off-boresight and azimuth angles
• Ansys HFSS Far-Field Data (FFD) import
• 2D interpolation for asymmetric beams and measured sidelobes
• Usable in point, coverage, footprint, and multibeam analyses

View Pattern tool

Inspect any antenna pattern before running a simulation: beam shape, sidelobe structure, and pattern quality, for the analytical models and imported patterns alike.

Carrier-to-noise

Carrier-to-noise density ratio (C/N₀, dB-Hz) and carrier-to-noise ratio (C/N, dB) from the receiver system noise temperature and channel bandwidth, to judge whether a link will close, not just its signal strength.

Figure of merit

Receiver figure of merit (G/T, dB/K) from receive gain and system noise temperature, to compare receiver and antenna configurations. A default 290 K is used when no temperature is specified.

Frequency shift

Doppler shift from the radial velocity between satellite and ground station. Positive when approaching, negative when receding; a 550 km LEO satellite reaches roughly ±280 kHz at Ku-band (12 GHz), scaling to about ±37 kHz at L-band.

Digital link BER

Bit error rate for BPSK, QPSK, OQPSK, 8PSK, 16QAM, and 64QAM from E_b/N₀ and the configured bit rate, with a code-rate based coded-BER estimate and symbol rate, in point, coverage, and multibeam analyses.

Flux density outputs

• Free-space PFD (dBW/m²) from effective EIRP and slant range
• PFD after atmospheric attenuation
• Spectral PFD normalized to a selectable reference bandwidth
• Reported per point, per grid cell, and per beam in multibeam runs

Limit masks and margin

• Article 21-style elevation-dependent limit mask (L₀ up to 5°, linear to L₂₅ at 25°)
• Built-in presets for C-band (3.7–4.2 GHz) and K-band (17.7–19.7 GHz)
• Custom limits and reference bandwidth
• PFD margin output: positive when below the selected limit

Save and load projects

Store a complete configuration, constellation, RF parameters, and analysis settings, as a JSON project, then reload it with every field repopulated.

TLE storage

Save live TLEs with their capture time and source alongside the project. Reload with the saved TLEs for identical positions, or fetch fresh ones for the current sky.

Record and replay

Record a live session and replay it later exactly as captured, with the same playback and scrubbing controls as synthetic runs.

Interactive 3D globe

• Heatmaps, footprint polygons, satellite markers, and ground links
• Click any heatmap point for satellite ID, Rx power, elevation, distance, gain, and losses
• Playback for synthetic modes: play/pause, restart, speed 1x–50x, timeline scrubbing
• Recording controls for live modes with elapsed and total time

CSV export

• point_analysis.csv – received power time series
• coverage_grid.csv – per-point coverage results
• satellite_footprint.csv – footprint boundaries
• multibeam_cinr.csv – CINR per beam
• access_intervals.csv / gap_intervals.csv – from the access report
• Link-quality, BER, and PFD fields included: C/N₀, C/N, G/T, E_b/N₀, BER, PFD margin