High resolution imagery is processed from the
satellite, this imagery is of impressive detail, with a resolution of
this is not quite good enough to determine the make of car but it can
seen from an altitude of 800Km. While we cannot download this data
from the satellite we are able to supply within days, making it ideal
many purposes such as disaster management, military applications, urban
applications etc in remote regions where data can be otherwise
to gather. below is an example of a quickbird sub-scene.
We are further able to deal with Ikonos data, though the slow delivery
makes this more useful for less time pressurized projects, it does
have the advantage of being far more cost effective if archived data is
OSIS owns and operates the only privately owned satellite reception ground station in South Africa (The only other one is run by the parastatal, CSIR). Due to the initial high start up costs of this equipment the first system was purchased in partnership with Climate Systems Analysis Group (CSAG) a department of the University of Cape Town in 1999 over a 3 year agreement after which the equipment reverted to OSIS. Since then the formal agreement has run out but the agreement has continued on bi-annual terms due to the initial successful implementation.
The demand for the derived products from the systems have been so great that we have purchased and commissioned a second entire system to ensure total redundancy and 100% reliable data feed for our clients. In the picture below the 2 sets of control units can be seen alongside each other on the shelf.
The reception equipment has been supplied by an English company, who have proven to be very reliable and provide excellent quality equipment (over 3 years operation on the one unit before the only failure on the unit) and consists of several modules. One section controls the tracking of the dish and consists of a 2 dimensional tracking parabolic dish with an azimuth and elevation rotators that allows the dish to track the satellite as it passes across the sky. The rotators are controlled via and auto-tracking unit and control box that is in turn controlled by a computer running the tracking software (the units can be seen on the photo below, the 2 silver units and the 2 top grey units). The other section receives the data transmitted by the satellite and this consists of the helical antenna and very high gain pre-amplifier attached directly to the antenna which is positioned at the focus point of the parabolic dish. The amplified signal then enters the receiver module (grey module with one gauge in photo) that receives the signal at the correct frequency and passes it on the decoder (bottom right modules) which process the signal to a computer readable format which in turn is passed on to the computer for further processing.
The entire data reception, assimilation and satellite tracking is controlled by the software provided with the equipment, unfortunately the software runs on MS Windows, which has proven to be the only point of weakness of the system, due to regular system crashes (These two machines are the only Microsoft OS systems at OSIS). The software is otherwise reliable and easy to use and provides a good user interface for the system. (A screen shot of the main tracking and reception window is provided below)
The raw data is continually streamed to the Linux computers where the data is processed into a industry standard format using custom software that converts the data to a format that is read by image processing software.
OSIS uses custom non interactive software to process the images into the published product allowing for no necessary user intervention in the entire process of reception to publication allowing more time for personnel to interpret the final product.
Initial product generation and data investigation is done using high end remote sensing software that is highly flexible allowing for data algorithms and manipulation techniques to be developed and tested. As this software can process nearly every type of satellite data available, we are able to process Ikonos, Quickbird, Landsat, Radar, EOS/Modis, Spot, Seawifs imagery as well others for special applications on request.
Affiliated to the Noaa Satellite Imagery that is received is the 10 channel data from the Chinese Feng Yun 1d satellite , the sensor is similar to the Noaa polar orbiters however it has 4 channels in the visible spectrum, thus the data can provide true colour image as well as provide information on biological activity in the ocean.