When it comes to the camera for CubeSat, space experts and engineers have used commercial off-the-shelf (COTS) innovations to improve reliability and the efficiency of the delivered results. Additionally, several experiments regarding the COTS sub-systems and components are being studied in universities.
The resolution of the CubeSat camera is all about resolving power; it is about the details visible within an image. And in this article, we will discuss everything there is about the camera resolution for CubeSat cameras.
What Are The Various Types Of Resolutions For A CubeSat Camera?
When selecting any camera for a CubeSat satellite mission, it is essential to know about various factors like integration, lead times, costs, and testing requirements. Additionally, you also need to know about the physical requirements of the systems.
Let us learn about some types of CubeSat camera resolution that you need to assess so that you can choose the right payload for your needs:
1. Spatial Resolution
When it comes to remote sensing, spatial resolution can be described as the smallest size of an object distinguished from its surrounding features or objects. The ability to separate or ‘resolve’ the small details is one of the many ways of describing spatial resolution. Spatial resolution by satellite sensor systems is mostly expressed in meters.
2. Spectral Resolution
By definition, spectral resolution refers to the size and number of bands in an electromagnetic spectrum that a remote sensing platform can capture. For instance, certain satellites use multispectral scanners to capture images using four spectral bands (two near-infrared, red, and green bands). On the other hand, satellites with hyperspectral resolution can capture more than a hundred bands on the electromagnetic spectrum.
3. Radiometric Resolution
Radiometric resolution can be defined as the sensitivity of a remote sensing platform capable of detecting slight differences in energy. In most cases, the remote sensing platform can be a passive or active sensor. Passive sensors utilize the electromagnetic radiation that reflects from the earth’s surface. In contrast, active sensors will use machine-made electromagnetic energy to record the radiation emitted back to the sensor.
4. Temporal Resolution
Temporal resolution is defined as the frequency of the imagery that is being recorded over a particular area. For instance, a satellite will observe and capture the same location for some days. Depending on the phenomenon being observed or questioned, this resolution can play an essential role in selecting the imagery.
Selecting An Appropriate Payload
Of course, there is no way of determining which CubeSat camera is the best for a type of mission. Hence selecting the suitable optical payload is a critical decision. Most end up underestimating the complexity of the choices that need to face while understanding the types of products in the market.
Some critical factors that will help you make the right choice include:
At times, engineers can forget that they are developing CubeSat camera modules for specific applications. An optical payload is so much more than just a simple space technology that can help take nice and Instagram-worthy pictures from space. You can consider it as a complex measurement system.
You need to ask yourself specific questions – what type of data and insight do you want to gather from this data. You also need to ensure that you can move on with the error levels included in the end-product.
2. Volume And Size
While optical and electronic miniaturization has developed in the past few years, it is essential to realize that some limitations exist with the small CubeSat camera size. Of course, the performance between a 1kg optical payload and a 100kg one will still be significant.
The limitations of the satellite’s size are more evident with CubeSats. Certain aspects cannot be exceeded, like structural, thermal, and physical limits; therefore, you should not expect miracles from these optical systems.
3. Modulation Transfer Function (MTF)
When it comes to spatial resolution, the figure of merit is Modulation Transfer Function (MTF), not Ground Resolved Distance (GRD) or Ground Sampling Distance (GSD). While these two parameters are crucial, you must use the proper comparison tools when choosing the suitable payload.
You need to ask yourself specific questions – what is CubeSat camera, and what type of MTF am I looking for? The kind of MTF you choose will eventually depend on the error margin that you can accept and the application. For high-end systems, you will require crisp images, which means you need an MTF of at least 20%.
4. Thermal Environment
One of the essential benefits of the CubeSat camera is that it can operate in a wide range of temperatures. However, the mistake here that most people make is the procurement of the optical payload.
As most of us already know, these cameras are susceptible to environmental changes; a slight movement can result in drastic performances. In the case of the thermal environment, you must be sensitive to the radial and axial temperature differences across the payload so that you get the best imagery.
In this article, we have learned about the basics of CubeSat camera resolution. The resolution is critical as it will dictate the type of images you get. Therefore, you need to take some time and consider all factors before choosing the right kind of optical payload for the satellite.