Technical solutions for the detection of communication terminals of various types, such as small satellite terminals (VSAT, Very Small Aperture Terminals), also in an urban environment, are of interest to the following users:
- Operators of VSAT networks to detect faults in the network caused by defective or incorrectly installed satellite terminals.
- Network agencies and regulatory authorities for the location and identification of illegally operating satellite terminals.
- Sovereign authorities and governmental services for the detection and location of satellite terminals, their operators and reconnaissance purposes (META data, content).
Goal of the project is the design, development and assessment of a payload, which allows the reception and the processing of the emitters to be located.
Today, systems are in operation that correlate the downlink signals from satellite terminals using the primary satellite and a secondary satellites (both in geostatio-nary orbits, about 36 thousand km above ground level) in two receiver channels. The location accuracy that can be achieved with this depends, among other things, on the following factors:
- Accurate knowledge of the ephemeris of the satellites.
- Antenna diagram of the emitter.
- EIRP (Effective-Isotropic-Radiated-Power) of secondary satellites.
- Availability and geometric constellation of secondary satellites.
In the L-band, the location precision is about 20 km, with an additional reference station about 9 km. Today Ku-band and spotbeam technology are increasingly used. The performance of the described location method is considerably reduced.
The use of two or more low-flying (160 km to 2,000 km) small satellites in a suitable flight constellation results in decisive advantages:
- No restriction on the frequency of the signals.
- The complicated determination of the ephemeris data of foreign satellites is not necessary. Just the position data of own satellites is necessary.
- Strong reception signals due to low signal travel.
- Short-duration and TDM signals are easier to receive and evaluate.
- Covering any area of the earth, regardless of the location of the emitters and geometric constellations.
- Various location methods are possible: TDOA, FDOA, AOA, combination of direction finding results from different locations.
The costs of the systems currently in use and those of the proposed system are roughly comparable. A standard Cube-Sat with all important components (power supply, space-link, computer, bus system, position control, etc.), including launch, track control and insurance costs today approximately 1 -1.5 million euro. In the future, satellite-based systems will be more cost-effective; the cost of orbital miniature satellites has declined considerably in recent years and will continue to drop as a result of standardized mass production for Cube and PocketQube satellites as well as falling launching costs.
|Title||LEOSig - Low earth orbit based signal intelligence|
|Short description||Small satellites (nanosatellite) in a low Earth orbit (LEO) allow the localization of dedicated electromagnetic emitters on the Earth's surface. The results provide information on the preparation of special situation picture images.|
|Technology||Location, LEO satellites, signal processing, tracking, sensor data fusion, software.|
|Markets||Network operators, operators of satellite communication systems, security oriented governmental services.|
Links and downloads
- DITS Projekte [pdf]
- DITS Projects [pdf]
- LEOLoc Informationsblatt [pdf]
- LEOLoc Information flyer [pdf]
- Wiki: CubeSat
- Wiki: VSat
- Wiki: VSat