SAR-Lupe
SAR-Lupe is a German satellite reconnaissance system. It consists of five identical small satellites and a ground station for satellite control and for image analysis. It is the world's third reconnaissance system with synthetic aperture radar technology, which can be independent of weather and time of day high-resolution images provide from any point on Earth. Previously, such systems were only in the United States and Russia in use, now also in Japan and Italy. Usable in the global exploration system in December 2007, the full range of services was achieved in 2008.
- 2.1 SAR-Lupe 1
- 2.2 SAR - Lupe 2
- 2.3 SAR-Lupe 3
- 2.4 SAR-Lupe 4
- 2.5 SAR-Lupe 5
- 3.1 client
- 3.2 Contractor
- 3.3 Collaborations ( E -SGA and FSLGS )
Technology
General values for the satellite
The satellites were brought into orbit in the years 2006 to 2008 Russian Kosmos- 3M carrier rocket from the Plesetsk spaceport (Northern Russia). The first satellite is in orbit since December 2006, and was successfully put into service in January 2007. As more satellites followed SAR-Lupe 2 on 2 July 2007, SAR-Lupe 3 on 1 November 2007, SAR-Lupe 4 on 27 March 2008 and SAR-Lupe 5 on July 22, 2008.
The weight of each satellite is approximately 720 kg, its size is set to 4 × 3 × 2 m. The estimated life span of 10 years, with an expected reliability of 97 % per year. The average power consumption is given as about 250 watts.
The satellites orbit in three different orbital planes in near polar orbit with an inclination of 98 degrees and an average orbital altitude of 500 km.
Since both the solar cell as well as the directional antennas are pivotally mounted on the satellite, the satellite has to be oriented differently depending on the operating mode. The alignment is done with the help of magnetic coils and reaction wheels. In addition, hydrazine thrusters are used for orbital control.
Imaging methods
Radar
The satellites use a Synthetic Aperture Radar (SAR ), regardless images can be obtained with the light and weather of each ratio. The SAR technique allowed by repeatedly picking a target from different angles and the appropriate post-processing of the data, a significantly higher resolution than its normal radar. The pulse repetition frequency for inclusion in the " high resolution mode " (spot light) is emitted sequentially focused at points approximately 11 seconds, the power thereby given subject to confidentiality. The parabolic radar antenna has a diameter of about 3 m and is immovably mounted on the satellite, so it must be turned completely to sight a target.
Radar technology has over optics besides the weather independence even more benefits for military reconnaissance: Sun Elevations can be better measured and moving speeds are determined. Since radar waves of water and metal are reflected particularly well, people and technical equipment (eg vehicles or mines ) can be recognized particularly well. This can partly be solved even through trees or camouflage nets. However, it is technically possible at least, with the help of a jammer ( jammer ) to impede or block the radar at all.
Einsatzmodi and the "magnifying glass " capability
The overflight can (normal, ground speed about 7 km / s, suitable for large-scale observation) in the modes ' Strip-Map ' done well ' spot - light' (high res ): in the latter, the satellite rotates so that the movement relative to the bottom ( at least partially ) is compensated and thus a higher resolution can be achieved.
The name "magnifying glass" comes from the ability to take particularly interesting destinations with a much higher resolution. According to the manufacturer, this is so far unique. This is made possible, inter alia, by combining the SAR technique ( possibly with two or more satellites at the same time ) and the spot -light maneuver in conjunction with the image edit software, which summarizes the parameters. When using the magnifying glass acts physically seen each particular movement of the target negative with respect to the resolving power, so the target should be as static. It is not publicly known how just affects the spot -light maneuvers on energy consumption and amount of data ( storage space and transmission bandwidth ). Also known are the time required to again return the satellite in the receiving position and how often such Mitziehmanöver is feasible. Swirl stabilization and trajectory control operations continuously consume energy, which can be partially offset by solar cells.
Resolution
In slow mode resolutions of less than one meter can be achieved. This refers thereby possibly only on the vertical resolution (transverse to the direction of flight). Note that the inclination angle of the satellite to the target area also affects the resolution. According to the manufacturer, the resolution is higher than the American and Russian radar satellites. The manufacturer sample images have edges widths of 5.5 × 5.5 m in " high resolution " and 60 × 8 m in " high resolution ". The width should be instrumental in actually limited by the radar technology, the length ( in the strip - map mode ) either through the internal data processing or the power supply. But it is certain that a real surface coverage only with considerably more satellites is possible; a restriction, each satellite system. Accurate information about the resolution regarding altitude and speed are not publicly available.
Was previously announced that in Afghanistan a previously unknown cemetery in the natural soil is under a German ISAF camp, which has tracked in 2007, the SAR-Lupe.
Ground station
The ground station was built from 2004 to 2006 in Gelsdorf near Bonn.
The base station is divided into two segments, the user (NBS ) and the satellite ground segment ( SBS). The former is basically taken over the target selection and evaluation of the images, the SBS takes care of the technical control, data exchange, and imaging ( the satellite itself makes no preprocessing, but provides only raw data).
Transmitting the data to the ground station
A link to the ground station is in principle only possible when the satellite is directly above it. For this reason, the recorded data must first be stored before they are received and processed at the base station. Due to the available on-board memory of about 128 GB, the number of images per day is limited to about 30 (maybe this limitation is set but also by the power supply or transmission bandwidth ).
For data transmission, the X-band is used ( via the same parabolic mirror, the radar emission), control and telemetry data is exchanged encrypted via S-band ( directly to the ground station or via inter-satellite link).
The average response time (time from customer request to return the pictures ) is 11 hours 95 % of the requests are, however, take up to 19 hours to complete. From a possible drastic reduction of hours by telemetry ships or mobile stations, as in the United States and Russia default, nothing is publicly known.
Comments
All technical values for capacity are given in the publicly available sources with only minimum values. It may well be that the actual maximum resolution is much higher. Maybe this value is about 50 cm, ie roughly twice as high as officially stated.
Release dates
SAR-Lupe 1
The first satellite was delivered on 21 September 2006 to the Federal Office of Defense Technology and Procurement. Before the start of the satellite went through extensive testing in order to test satellite center of IABG.
For the start of the Cosmos 3M launch vehicle had to be modified because the SAR -Lupe satellites are too large for the standard version. A special adaptation of the payload fairing solved the problem. The new fairing has been tested in early 2005 on a flight of Kosmos 3M with a Russian satellite successfully.
SAR-Lupe 1 was launched on 19 December 2006 14:00:19,562 clock (CET) in Plesetsk with a Cosmos -3M rocket. About 90 minutes later, the first data was received. The satellite has reached its orbit is stable, responds to commands and sends data.
On 8 January 2007, the satellite control was handed over to the military ground station. January 19, 2007 announced the manufacturer OHB Technology of Bremen, that the functionality of the entire image acquisition chain ( radar image, attitude control, transmission, processing) was demonstrated: in all shooting images were successfully delivered to the expected quality.
SAR-Lupe 2
The original launch date for SAR - Lupe 2 on 1 July was postponed by one day due to strong winds aloft. SAR-Lupe 2 was then started on July 2, 2007 at 19:38:41 UTC with a Cosmos -3M rocket from the Russian space center Plesetsk south of Archangelsk. The radar satellite was exposed about a half hour later in its low Earth orbit at about 500 km altitude. A first life signal was received at 20:41 UTC clock on the ground station Kerguelen in the southern Indian Ocean. The direct contact between the control center and the satellite as planned made 92 minutes after the start. SAR-Lupe 2 functioning properly after the first tests in orbit, so that was already started with the commissioning of the night. The fold out the antenna was successful.
SAR-Lupe 3
SAR-Lupe 3 was completed in the fall of 2007 and was successfully launched on 1 November 2007 with a Cosmos -3M rocket from the Russian space center Plesetsk from. With this launch, the experimental communication payload Rubin-7/AIS was as an additional passenger on board the rocket.
SAR-Lupe 4
On March 27, 2008 at 18:15 hours SAR-Lupe 4 was started successfully. The launch had previously been postponed twice due to bad weather conditions.
SAR-Lupe 5
The fifth and so far last satellite of the system was successfully launched at 4:40 clock CEST on 22 July 2008, a Kosmos- 3M rocket from the Russian space center Plesetsk from.
History and manufacturing
The SAR-Lupe system is actually a low-cost solution: the predecessor project Horus was canceled because the cost of up to 5 billion marks of the federal government were too high. Thus in 1998 began working with the SAR - Lupe system, which was originally only should have cost about 370 million euros. In 2008, the Bundeswehr plan current total expenditure totals 746 million euros. This was achieved firstly by limitations in performance ( as, for example, the radar can not be pivoted must instead the entire satellite will be rotated ), but especially by the use of already existing items, the small satellite design and by the award of subcontracts on the respective best suppliers ( less than half of the items are from Germany ). The final contract was finally signed on 17 December 2001.
Client
The system is under the Bundeswehr, the German Federal Ministry of Defence client are ( FMOD ) and the Federal Office of Defense Technology and Procurement ( BWB). The newly formed "Department satellite-based reconnaissance " (Abt SGA ) of the Strategic Reconnaissance Command ( KdoStratAufkl ) operates the user ground segment. The nominal strength of this department is 31 officers, 39 NCOs and 23 civilian employees.
The following services can take the system to complete:
- Operational Command of the German Armed Forces ( EinsFüKdo Bw )
- Forces Command of the armed forces ( TSK FüKdo )
- Geoinformation Office of the German Federal Armed Forces ( AGeoBw )
Contractor
The preparation of the SAR-Lupe system is subject to a consortium of European companies, led by OHB -System AG, which is also responsible for the overall management and operates the satellite ground segment.
Contractor for the satellite bus are OHB-System, Carlo Gavazzi Space, OHB Teledata, STS Systemtechnik Schwerin and RTG Aero - Hydraulic and for the SAR payload Tesat Spacecom, Thales Alenia Space, SAAB Space and RST Radar Systemtechnik. In addition, OHB are responsible for the ground segment OHB-System, Carlo Gavazzi Space and EADS. For satellite launches Cosmos and Rosoboronexport were tasked with the start and Inbetriebsnahmephase DLR GSOC. RST was responsible for the interpretation of SAR sensors and the development of the SAR processor.
Collaborations (E -SGA and FSLGS )
On July 30, 2002, a cooperation agreement with the French army was closed in Schwerin, which uses the Helios system for optical satellite reconnaissance. Due to the complementary, the two systems well, they are to be coupled. The interface that allows the French military, to gain access to the SAR-Lupe satellite, called FSLGS ( "French SAR-Lupe ground segment "). In return, the French are a way to access the Helios system.
On 1 December 2006, the OHB Technology was awarded by the Federal Office of Defense Technology and Procurement to order for the realization of the reconnaissance system. The order is worth around 87 million euros.
It is hoped that other EU countries participate with other satellites. The aim is to creating, a joint reconnaissance system for the EU. This has been already taken into account in the technical planning phase: the system is modular and easily expandable. The entire multinational system network is being developed under the name E -SGA ( " Europeanization of Satellite -Based Reconnaissance ").
Follow-up system
The Bundeswehr plans to create three new satellites for about 800 million euros. The overall project management should be at the Bremen company OHB -System AG again. The new system called SARah should be available in its entirety in 2019 and replace the previous SAR -Lupe satellites after their service life. The three new satellites (two with the existing radar technology, one with a so-called phased array radar) will be larger and more powerful.
In addition, should be purchased to reduce the related dependency of France for 170 million euros, a satellite for optical reconnaissance.