Future trends and expected technological evolution - Access time
From INVESaTWIKI
[edit]
Future trends and expected technological evolution - Access time
One of the characteristics of Earth observation satellites systems is the access time, i.e. the time needed to make available to a user an image he requested. This time is composed of three parts:
- Programming: elaborating the command then sending this command to the satellite.
- Note: The following have to be taken into consideration: list of requests and priorities, availability of the satellite, visibility of the satellite from ground station (antenna), proximity of the satellite to the scene to be observed, etc.
- Taking the image: The satellite from an orbital position where it can see the scene is oriented towards it and captures the image and then stores it on board for later retransmitting it to ground stations.
- Distributing of the image: when the satellite arrives in visibility zone of a station, it transmits the image and the image is received by the ground, which transmitted to a processing centre. Later the image is served to the user its demand.
Currently the Earth observation satellites, in Low Earth Orbit (LEO), operate with a very small number of stations transmitting order and command, and receiving image data. To improve the access time several tracks are possible:
- Increase the number of stations and the number of satellites in orbit.
- Interconnect the stations with the processing centre and the users through high-speed telecommunication links (Internet or VSAT or other).
- Develop software and more generally tools to ease processing of image data. [1]
[edit]
References
[1] D.Hernandez
"Possible scenario for future mission in Earth observation".
