Tel:
+86-0431-81785188
On September 20, 2024, Chang Guang Satellite Technology Co., Ltd. (hereinafter referred to as "Chang Guang Satellite") launched the Jilin-1 Wide-Band 02B01-06 satellites into space. These six satellites are consistent in model and are small-batch produced ultra-wide, high-resolution optical remote sensing satellites.
While achieving a spatial resolution of 0.5 meters, these satellites have an impressive swath width of 150 kilometers and weigh only 230 kilograms, making them the lightest and broadest optical remote sensing satellites with sub-meter resolution internationally.
Internationally, optical remote sensing satellites with sub-meter resolutions of 0.5 meters typically have imaging swath widths ranging from 5 to 20 kilometers. This figure is an order of magnitude lower than the swath width of the Jilin-1 Wide-Band satellites. Does this mean that their imaging coverage capability is also an order of magnitude lower? The answer is no. Sub-meter satellites with lower swath widths generally emphasize agile performance, capable of compensating for the swath width deficiency via large-angle, rapid maneuver imaging. So, which is better: ultra-wide swath or agile sub-meter optical remote sensing satellites?
The imaging swath width of a remote sensing satellite refers to the ground width range that its camera (sensor) can cover in a single shot or scan, representing its field of view in one imaging session. For the same spatial resolution, the larger the swath width, the larger the ground area it can capture in one imaging session, enhancing its imaging ability. However, for the same camera, spatial resolution and swath width are two mutually restricting metrics; similar to the human eye analogy, observing a target up close for details reduces the field of view (swath width), and conversely, a larger field of view blurs the target details.
Ultra-wide swath refers to a very large width of the imaging strip in a single imaging session. Medium- and low-resolution remote sensing satellites can reach thousands of kilometers, whereas there is no defined boundary for ultra-wide swath sub-meter optical satellites; here, it is defined as a swath width greater than 100 kilometers. Currently, the only commercially operating ultra-wide swath sub-meter optical remote sensing satellites in orbit are the ten wide-band satellites of Chang Guang Satellite and the Siwei Gaoge III-01 satellite from China Siwei.
Agile remote sensing satellites are those with rapid response, high maneuverability, and flexible imaging capabilities, capable of making quick and precise maneuvers in different orbital directions to achieve multiple and multi-angle observations of ground targets, supporting various mission modes, including but not limited to multi-target observation, multi-strip mosaic imaging, and multi-angle stereo imaging.
Ultra-wide swath sub-meter optical remote sensing satellites achieve both high resolution and wide swath, thereby somewhat achieving the best of both worlds. Their advantages include:
Ultra-wide swath greatly enhances the ability to acquire sub-meter high-resolution data.
Ultra-wide swath in a single imaging session improves the consistency of radiation data, aiding in subsequent image data color balancing and mosaicking. Despite the clear swath advantage.
The greatest advantage of ultra-wide swath sub-meter satellites lies in their ultra-wide swath, whereas agile satellites' greatest strength lies in their flexible imaging. The advantages of agile sub-meter optical remote sensing satellites are:
Agile and flexible imaging improves image acquisition efficiency, better meeting users' custom imaging needs. Satellites can quickly adjust their posture to achieve multi-angle and multi-directional imaging; multi-strip mosaicking expands the imaging swath; large-angle side-sweep imaging effectively broadens the geographical range that can be captured, shortening revisit times for point targets.
Less affected by weather, imaging areas can be planned based on historical weather data and weather forecasts. Smaller swath allows multiple maneuver imaging sessions to more effectively avoid cloud and rain interference.
Swath width is an important metric for sub-meter optical remote sensing satellites, but it's insufficient for comprehensively evaluating their capabilities. Choosing between ultra-wide swath and agility represents two different technical routes, both responding to market user needs, aiming to enhance the imaging acquisition capability of sub-meter optical satellites.
If we must determine which is better, it ultimately depends on the image products. It might not be important which is stronger, agility or ultra-wide swath, as having the capability to possess both would be ideal. A constellation network comprising both ultra-wide swath and agile sub-meter optical remote sensing satellites would achieve superior sub-meter optical imaging capability.