Magnetic Recording of Radar Data

Abstract

The methods presently utilized for magnetic recording of radar data are explained with reference to basic radar types. The PPI radar has a time continuous video signal and generally requires a transient free recorder of moderate data bandwidth. In addition, means must be provided to record the azimuth information in either synchro, sine-cosine or digital form. Such means are available and recommended approaches for each type of data are given. Time discontinuous radar such as the missile tracking monopulse group may utilize recorders normally designed for video service if certain pulse spacing criteria are observed. The wider data bandwidth of this type of signal makes the use of rotary head recorders mandatory. There are many applications for radar recording. Some of those described include operator training, debriefing and scoring and operational evaluation of the radar facility. The radar recorder can be a significant aid in data analysis for signature determination of satellites and planetary mapping. The radar recorder also furnishes a close facsimile of the operating radar signal for system evaluation when there are no targets to observe or when the main radar is shut down for any reason. As an illustration of the application of magnetic recording to the radar system an airborne data acquisition recorder is described along with a companion ground reproducer. These two units are presently in use in the evaluation of an airborne radar system and offer significant advantages over previously available recording equipment. The development of time base stable magnetic tape recorders capable of handling data bandwidth in excess of 5 MHz has added another facet to the instrumentation field - that of recording radar data on a real time basis for analysis at a later time. The discussion that follows illustrates the methods used in magnetic recording of radar data and cites a typical recording system.