Small satellites have grown dramatically over the past decade—and they are still growing fast and furiously. In this post, you'll learn about how to achieve mission success for satellites and how GPS disciplined oscillators (GPSDOs) can do the trick.
A Growing Space
The initial surge of small satellites has been attributed to the curiosity of research and development. Much of this research is affiliated directly with universities, research centers, or government bodies such as NASA and NOAA. New technology development includes payloads such as:
- Science instrumentation
- Communications
- Radar applications
- Sensors
Small satellites soon took on the platform of a cubesatellite. Cubesatellites are essentially a form factor for a satellite design highly driven by the need for standardization to keep costs down for launch vehicle compatibility. The success of this initial surge of smallsats has caused the private industry to provide their undivided attention to the concept as a means for profitable business opportunities.
With launch vehicle costs going down and large-scale manufacturability becoming commonplace for the cubesatellite platform, many startups have been receiving generous investments from venture capital firms for their business propositions.
The Importance of Timing in Cubesatellite Missions
Big data has been the business plan for quite a few of these small startups. Some examples are:
- Tracking maritime vessels
- Weather forecasting
- Tracking emissions to determine carbon footprints geographically
- Obtaining world imagery in a timely fashion
Although these startups have different missions, there is one item that remains constant, which is utilizing the cubesatellite platform as a means to an end to support their value proposition within the big data industry. Connectivity is another application (not necessarily using cubesatellites as the platform) that has also been getting a lot of media outlet attention, since global coverage requires a much larger LEO constellation size. There is one critical component within the cubesatellite design that many of these startups consider as an instrumental portion for having successful and reliable missions.
The concept of timing amongst satellites within a constellation has become a significant technical challenge. By way of example: For a very large LEO constellation providing connectivity, a satellite is constantly traversing in its orbital plane at fast speeds. As it leaves a particular coverage area, it needs to coordinate a handover to the next satellite approaching that very same coverage area. There is a need for high precision timing so that this handover goes seamless without any data loss.
Reliable connectivity service is one of the primary criteria for user experience, and precision timing is one of the key enablers for good user experience. Another example that is more applicable and prevalent for a cubesatellite platform is the need for time synchronization amongst multiple satellites to perform a mission task in concert. Examples include tracking a maritime vessel, taking an image, or even relaying mission data through inter-satellite links to downlink the data to a ground station.
The Timing Solution for Mission Success: GPSDOs
A great way achieve mission success is by using a GPSDO. GPSDOs work well as a source of timing because the satellite’s signals must be extremely accurate to provide positional accuracy for GPS in navigation. These signals are accurate to the nanosecond and provide a good reference for timing.
In the next post, we will further discuss the design, architecture, and functionality of GPSDOs—so stay tuned!
