X-band radar (SAR), 3 m and 1 m

Synthetic aperture radar sees through cloud and in the dark. Calm water is black, buildings and steel return bright, and two passes show what moved.

Grey radar image of farmland, field boundaries and circular pivots visible as different brightness — Radar backscatter (VV), 28 July 2025. Field texture and pivot circles show up although radar measures roughness and moisture, not colour. Imagery: Contains modified Copernicus Sentinel data (2025), Sentinel-1 C-band, radiometrically terrain corrected. Perihel radar is X-band at higher resolution.

Specification

PH-R payload on the Perihel standard bus, orbit 525 km sun-synchronous.

Frequency	X-band, 9.65 GHz
Imaging modes	StripMap 3 m, Spotlight 1 m
Swath width	30 km StripMap, 6 km Spotlight
Polarisation	Single: HH or VV, chosen per tasking
Incidence angle	20° to 45°
Noise floor (NESZ)	−22 dB
Radiometric accuracy	1 dB, 3-sigma
Revisit, one satellite	3 days; any light, any weather
Daily capacity	Up to 18,000 km² StripMap
Antenna	Deployable 3.2 m by 0.5 m phased array
Power during acquisition	Peak 600 W, 10 minutes of imaging per orbit
Downlink	X-band, 800 Mbit/s

Products and formats

Every scene is delivered as a cloud-optimised GeoTIFF with a STAC item. Levels are cumulative: you can order L1B and reprocess to L2 later.

Product levels
Level	Content	Format	Delivery after downlink
SLC	Single-look complex, phase preserved, slant range	SICD (NITF 2.1), complex int16	35 min
GRD	Ground-range detected, multi-looked, calibrated backscatter	COG GeoTIFF, float32	40 min
GEC	Geocoded and terrain corrected, speckle filtered option	COG GeoTIFF	50 min
Change	Coherence and amplitude change between two passes	COG GeoTIFF	60 min after second pass
Masks	Flood extent and ship detections	GeoJSON polygons and points	45 min

Example products

Radar image of a farmed plain before the flood, mid-grey fields — Before: 1 September 2023.

The same radar image after the flood, large black areas where water covers the fields — After: 13 September 2023. Open water is black.

Imagery: Contains modified Copernicus Sentinel data (2023), Sentinel-1 C-band VV, Thessaly, Greece, after Storm Daniel.

Resolution and revisit

Revisit of a mid-latitude point improves with every satellite you add to the plane. See the coverage page for the ground tracks.

Revisit by fleet size
Satellites	Revisit
1	72 h
3	24 h
6	12 h
12	6 h

Try the coverage calculator

Typical uses

Flood mapping: Open water is dark in radar. A before and after pair gives flood extent through the storm cloud.
Maritime surveillance: Ship detection and dark-vessel alerts in open sea, with length estimates.
Ground motion: Millimetre-scale subsidence of pipelines, dams and city blocks from repeated passes.
Infrastructure and mining: Stockpile change, tailings dam movement and construction progress under cloud.

Sample delivery

Each scene arrives with a STAC item that any STAC client reads. Query it through our API or find it next to the data in your own bucket.

Delivered item, abbreviated

{
  "type": "Feature",
  "stac_version": "1.0.0",
  "id": "PH-RAD-20250728-173012-0412",
  "collection": "perihel-radar-grd",
  "properties": {
"datetime": "2025-07-28T17:52:40Z",
    "perihel:level": "GRD",
    "gsd": 3,
    "sar:frequency_band": "X",
    "sar:polarizations": ["VV"],
    "sar:instrument_mode": "SM",
    "sat:orbit_state": "descending",
    "view:incidence_angle": 34.2
  },
  "assets": {
    "data": { "href": "s3://your-bucket/perihel/perihel-radar-grd/PH-RAD-20250728-173012-0412.tif",
              "type": "image/tiff; application=geotiff; profile=cloud-optimized" },
    "metadata": { "href": "s3://your-bucket/perihel/perihel-radar-grd/PH-RAD-20250728-173012-0412.json" }
  }
}

Questions about radar

Task a radar satellite

Tell us the area and the revisit you need. An engineer replies with orbit, sensor and fee.

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