The history of the PS Logger® is one of continuous development, beginning in 1979 with the collaboration between OYO Corporation Japan, the parent company of Robertson Geo and Prof. Kitsunezaki (Akita University).
The new system was introduced by OYO as Suspension S Wave logging:
The updated development of 1984 improved the structure of the source to generate both P-wave and S-wave with the “new Suspension PS Logging System” being introduced:
A new source of improved efficiency called HS Source was introduced and development, sales and manufacture was transferred exclusively to Robertson Geo in 1988:
Robertson Geo has continually developed and updated the PS Logger® with customers and its own service teams deploying the system globally acquiring important high value data from many thousands of boreholes.