3.6° N · 705 km · swath 185 km
Inclination 98.21° · retrograde, sun-synchronous
Satellite
Footprint
Mapping drone
L0 · Raw instrument counts
L1 · Calibrated, geolocated
L2 · Analysis-ready: reflectance or backscatter
L3 · Composite of many acquisitions
Catalog
Collection
Item · one scene
Assets · COG bands, metadata
COG overviews · coarse to full resolution
Ground station · tracking antenna
Bow Valley, Alberta
Intro.
Earth observation & GeoAI · Explainer
Seven steps of an Earth-observation chain, each worked live: the orbit that sets the revisit, the geometry that sets the resolution, the pass that sets the data volume, the processing levels, a change-detection pass, a drone campaign and the catalogue that serves it. Every number below is computed live from your inputs.
01 · Orbit and revisit
A sun-synchronous orbit precesses with the Sun, about 0.9856° a day, so every pass crosses a latitude at the same local time. The Earth’s oblateness supplies the precession, so altitude fixes the inclination: cos i = −2Ω̇a7/2 / (3J₂Re²√μ). Kepler gives the period, T = 2π√(a³/μ). With the swath and the orbits a day, that sets how long the equator takes to cover at nadir.
02 · Acquisition geometry
A synthetic aperture radar looks sideways and resolves the ground by the timing of its echoes, so its ground resolution improves as the incidence angle grows. An optical imager resolves by angle, so its pixels stretch as it points away from nadir. Radar slant-range resolution is c/2B and its ground-range resolution divides that by sin θ; the optical across-track pixel grows as 1/cos²θ.
Sensor
Chirp bandwidth
03 · Downlink
A ground station can only work a satellite above its elevation mask: terrain, buildings and the atmosphere set it. The pass is the arc of the orbit above that cone; its length times the link rate is the data volume. The overhead pass is the longest: the Earth central angle λ = arccos(Re cos ε / (Re + h)) − ε sets it, and every pass off the ground track is shorter.
Downlink rate
04 · Processing levels
Level 0 is the instrument’s raw stream. Level 1 is calibrated and located. Level 2 is a physical quantity per pixel, surface reflectance or backscatter, and is analysis-ready when it meets the CEOS ARD requirements. Level 3 composites many acquisitions into one. A scene’s volume is its pixels times bands times bit depth.
Scene width
Steps: 1 · 3 · 10 · 20 · 30 · 60 mBands × bit depth
05 · GeoAI change detection
On the Bow Valley terrain, slope failures are seeded on ground steeper than 32°, and a detector scores every analysis cell (369 × 590 m). Raise the threshold and false alarms fall while misses rise. Red cells are detections; outlined cells are the seeded failures.
06 · Drone campaign
For a mapping camera, the ground sample distance is sensor width times altitude over focal length times image width. Altitude and overlap then set the line spacing, the photo count and the time in the air.
Camera class
07 · Catalogue and tiles
A SpatioTemporal Asset Catalog describes every scene as an item with assets. A Cloud-Optimized GeoTIFF stores overviews and internal tiles, so a client reads a few kilobytes over HTTP range requests instead of the whole file. At zoom z a Web Mercator pixel spans 2πR / (256 · 2z) at the equator.
Seven steps of an Earth-observation chain, each worked live: the orbit that sets the revisit, the geometry that sets the resolution, the pass that sets the data volume, the processing levels, a change-detection pass, a drone campaign and the catalogue that serves it. Every number below is computed live from your inputs.
A sun-synchronous orbit precesses with the Sun, about 0.9856° a day, so every pass crosses a latitude at the same local time. The Earth’s oblateness supplies the precession, so altitude fixes the inclination: cos i = −2Ω̇a7/2 / (3J₂Re²√μ). Kepler gives the period, T = 2π√(a³/μ). With the swath and the orbits a day, that sets how long the equator takes to cover at nadir.
A synthetic aperture radar looks sideways and resolves the ground by the timing of its echoes, so its ground resolution improves as the incidence angle grows. An optical imager resolves by angle, so its pixels stretch as it points away from nadir. Radar slant-range resolution is c/2B and its ground-range resolution divides that by sin θ; the optical across-track pixel grows as 1/cos²θ.
A ground station can only work a satellite above its elevation mask: terrain, buildings and the atmosphere set it. The pass is the arc of the orbit above that cone; its length times the link rate is the data volume. The overhead pass is the longest: the Earth central angle λ = arccos(Re cos ε / (Re + h)) − ε sets it, and every pass off the ground track is shorter.
Level 0 is the instrument’s raw stream. Level 1 is calibrated and located. Level 2 is a physical quantity per pixel, surface reflectance or backscatter, and is analysis-ready when it meets the CEOS ARD requirements. Level 3 composites many acquisitions into one. A scene’s volume is its pixels times bands times bit depth.
On the Bow Valley terrain, slope failures are seeded on ground steeper than 32°, and a detector scores every analysis cell (about 370 × 590 m). Raise the threshold and false alarms fall while misses rise. Red cells are detections; outlined cells are the seeded failures.
For a mapping camera, the ground sample distance is sensor width times altitude over focal length times image width. Altitude and overlap then set the line spacing, the photo count and the time in the air.
A SpatioTemporal Asset Catalog describes every scene as an item with assets. A Cloud-Optimized GeoTIFF stores overviews and internal tiles, so a client reads a few kilobytes over HTTP range requests instead of the whole file. At zoom z a Web Mercator pixel spans 2πR / (256 · 2z) at the equator.
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