The group of high-professional researchers in the development and implementation of high-speed signal processing systems led by scientist Yury Artyukh has been dealing with high-precision time counting problem from 1970th. In 1970-1990th the group had leading positions in USSR in the area of high-precision time-of-flight measurements. The most of Soviet Satellite Laser Ranging (SLR) stations have been equipped by the timing systems made in Riga. Previous time counter devices could not provide the measurement of the overlapping time intervals, until in the 1990th the first Event Timer – the device providing epoch registration of incoming events was developed.
Such Event Timer (ET) was especially needed for the first laser-ranging of the moon – the natural satellite of the Earth because the time-of-flight for ranging of the retroreflectors at the moon is in the range from 2.42 s up to 2.71 s. In case of using the time counters the laser ranging repetition period should be about 3 s or frequency about 0.35 Hz. The ET allows increasing the laser ranging of the moon up to kHz and higher.
EDI research in the area of Digital Signal Processing (DSP) technology in 1990 – 2000th has led to innovative DSP-based technology for the high-precision event timing.
The DSP-based approach developed under the leadership of Yury Artyukh not only provides for excellent performance characteristics of ETs, but it also leads to almost full replacement of the highly specialized hardware by typical DSP facilities, reducing the hardware implementation cost. An attractive price-performance ratio has made these instruments quite competitive as compared to the other instruments similar in functionality and quality. The last most advanced model A033-ET for a terrestrial application provides a sub-millimetre accuracy and up to 20 million events per second registration rate. A033-ET became widely used around the world in KHz Satellite Laser Ranging (SLR) to provide a millimetre ranging accuracy and about half of all SLR stations in the world have this ET.
In 2011 on the basis of a Licensee Agreement, the rights for manufacturing and distributing of A033-ET was transferred to Eventech Ltd (Latvia). Today, thanks to great efforts of the Eventech more than 100 A033-ET are sold to USA, China, Germany, Finland, England, Austria, Poland, Lithuania, Russia, Korea, Japan. Eventech carries out the market research of applications of event timers, not only in SLR and Time Transfer by Laser Link but also in other fields of science and technology and has found their application in gravimetry, LIDAR and 3D-scan systems, TOF-spectrometry and others. In 2016 Eventech won a grant from the European Space Agency (ESA) for the development of a multi-purpose event timer for space applications. EDI as a subcontractor of the Eventech has developed such timer and carefully tested with a space environment simulation. The verification results are highly appreciated by ESA, and they have proposed to participate in a number of space missions using the developed event timer for LIDAR systems and for altimetry in the space-ship equipment.
Executing research projects and contracts related to the development of high precision and high-performance ET for different applications, EDI has developed the family of compact ETs and each of these ETs are carefully tested. EDI has experience in creating application-specific timing systems and in testing with sub-picosecond accuracy.
Besides the experience and self-developed methodology of subpicosecond ET testing, EDI has all necessary equipment for testing purposes including self-developed high stability test generators, different arbitrary frequencies generators, high performance oscilloscopes, optical table with necessary components for laser pulse generation, splitting, reflection and receiving, wide range temperature and humidity chamber and vibration system.