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This report describes the theory and operation of a multipulse correlator for the DNA 617 radar now located at Chatanika, Alaska. The hardware correlator is of a novel design that utilizes patch-wire programming to select the particular lags that are to be computed. The unit can deliver as many as 40 8-bit-by-8-bit signed products every 20 micrometers, at any of 48 3-km range gates that are specified under computer control. (Modified author abstract)

The report summarizes the 1973 SRI research efforts associated with the Chatanika incoherent-scatter radar. Additions and improvements to the radar hardware are described. New software and modifications to existing software were implemented. The functions of these programs are described. Over 180 hours of data were recorded during the year and the dates, times, and purposes of radar operation are listed. The research results are summarized in the form of abstracts of papers that have resulted from the project efforts. (Author)

The report describes the ionospheric studies performed between June 1969 and May 1970 using the DASA Project 617 incoherent-scatter radar. During this time period, significant improvements were made in the radar system to allow nearly real-time processing of the data and to increase the accuracy, time resolution, and altitude extent of the measurements. The 1970 measurements presented here are the first to be made using the new system. The daytime F- layer over Palo Alto between 1967 and 1969 was studied to determine (1) its seasonal behavior, (2) its day-to-day variations, and (3) its correlation with solar geophysical indices. Continuous 48-hour data runs were made in 1969-1970 and were used to study the ionosphere's diurnal behavior as well as its seasonal behavior during the sunrise and sunset periods. A new type of measurement, the determination of ionospheric vertical velocities, was made for the first time in 1970. Increased upward velocities during the sunrise period were found to exist. Observations of the F-layer during two partial solar eclipses were made and are reported. (Author), See also Part A, AD-873 313L.

This report describes in detail the use of the Project 617 radar for making incoherent scatter measurements of the ionosphere. The data processing and analysis methods are fully explained, including all the assumptions, interpolations, and extrapolations. Two new major computer programs were implemented. Portions of the radar hardware that are especially important to the incoherent scatter measurements and portions that have been developed, modified, or improved during the past year are also described. The development and implementation of a digital autocorrelator, in combination with new computer software, has resulted in an order-of-magnitude improvement in data processing time, as well as a significant improvement in measurement accuracy. (Author)

The report describes the ionospheric studies performed between July and November 1971 using the DNA Project 617 incoherent-scatter radar. The diurnal and (to some extent) seasonal behavior of the auroral ionosphere has been studied using 24-hour continuous data. Measurements on the auroral E-layer have shown densities as high as 1.8 x 10 to the 12th power el/cc. Other characteristics of the auroral E layer that have been studied include its thickness, electron-density gradient, production rate, and recombination coefficient. Velocity measurements have been made that show the normal as well as disturbed behavior. Ionization drift velocities as high as 200 m/s have been measured. The latitudinal distribution of ionization over several degrees of magnetic latitude has been observed and on several occasions the position of the northern boundary of the plasma trough has been determined. Also described are cooperative experiments in progress with satellites, the Homer multifrequency auroral radar, and various auroral-zone geophysical measurement programs. (Author)