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Satellite laser ranging system for low earth orbiter observations

Design of a small-sized mobile satellite laser ranging system (slr) with a high capability to track fast-moving low earth orbiting satellites including the zenith zone. The main innovation is the pilot project of the semi-automated slr.

Satellite Laser Ranging system (SLR) observations are important for satellite orbit determination. Currently in the orbit are LEO (Low Earth Orbiter) satellites CHAMP, GRACE, ENVISAT, BEC, SUNSAT, WESTPAC, GFO-1, TOPEX, ERS-2, AJISAI, STELLA, STARLETTE and many other of the high orbit satellites (including LAGEOS-I, LAGEOS-II, GPS and GLONASS). The SLR observation reports demonstrate that the observations of these satellites are overcrowded and it is rather difficult to perform the observation programmes. In the year 2005 it is planned to launch the GOCE on a very low orbit. The new satellite gravity missions (CHAMP, GRACE and GOCE) will substantially improve our knowledge of the gravity field and thereby of the (quasi-) geoid. The geoid will be determined to within 1 cm at wavelengths down to 100 km. All these satellites will have an onboard Global Positioning System (GPS), however the SLR observations are important to acquire the higher accuracy orbital measurements. They are very important also for altimeter calibration for the satellites JASON, ENVISAT, ICESAT, etc. The number of Earth exploring LEO satellites with laser reflectors is still growing and the new SLR designed in Riga is expected to be very useful. The main objective of a new project on an SLR telescope mount together with its optical and mechanical components, electronics, computer software and timing system is to design a mobile SLR of small size with a high capability to track fast-moving LEO satellites including the zenith zone. The design of the SLR mount has allowed the minimum size and weight for a system which features a 35 cm primary mirror carried on an alt-alt mount, driven by stepper motors. The entire system, including the mount drive, angular encoders, laser firing control, gating control, rotating mirror control, range, time and meteorological information interfaces, as well as software including predictions, data processing, normal point computation, reporting, communications, etc., will be controlled by a single PC (Personal Computer). The system is expected to have a low weight. It will be fixed in a case and can be moved by almost any vehicle, including small cars, without dismantling the SLR. The final aim is to develop the fully automated system. The main innovation lies in the pilot project of the semi-automated SLR with further attempts to make a fully automated system. Keywords: laser, ranging system, optical system, telescope mount, control electronics.
Acronym: 
LEO SATELLITE
Project ID: 
3 095
Start date: 
01-11-2003
Project Duration: 
37months
Project costs: 
100 000.00€
Technological Area: 
Laser Technology
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.