Semi-Automatic Ground Environment (SAGE) (Read 1,655 times)

Pat: One of our members who posted recently sounded like he/she was a "scope dope" and may be able to help with info. I had heard the same stories about SAGE capabilities as were listed in the Air Force Mags article on the six.

Forgot to mention that each Six had a unique aircraft address dialed up on its data link receiver so the SAGE commands received were specific to each aircraft.

I started a SAGE page on the site at www.f-106deltadart.com/sage_system.htm any input, corrections, complaints are welcome.

Great start Pat. I've got some more stuff on the Six I'll send you. Meanwhile, first paragraph under the SAGE / Six area might be a bit of a stretch. Pilot still had to lock on target, select and arm the weapon, and pull the trigger to fire. He also maintained throttle control.

By the way, TDDL should be Time Division Data Link, not Time Delay. My bad.

Pat, here's the additional info on SAGE. Please use as you see fit.

SAGE and the F-106
The primary means of communication between SAGE and the F-106 was accomplished using time division data link (TDDL). Signals from the SAGE AN/GKA-5 transmitter were received by the F-106 data link receiver; either an AN/ARR-60 or AN/ARR-61. SAGE provides two modes of control for interceptor command and navigation: close control and modified close control. The SAGE transmission would dictate which of the two modes would be dominant in a given scenario.

Close Control (CC). The primary mode of the data link was close control. In this mode, the SAGE transmitter would send an encoded message to the aircraft data link receiver which would check it for validity and proper aircraft address before sending the information on to the MA-1 computer. The MA-1 computer would in turn use this information to send commands for mach, altitude and heading to the Automatic Flight Control System (AFSC) and cockpit displays for vectoring the interceptor towards the target. While the AFSC could automatically accomplish the altitude and heading commands, the pilot needed to manually adjust the throttle to achieve the command speed.

Modified Close Control (MCC). When an F-106 was paired up with a target, in addition to the altitude, speed and heading CC commands for the interceptor, SAGE would also send MCC messages that contained extensive target information. The data link receiver would validate the messages and pass them on to the MA-1 computer. The MA-1 computer would use this information to calculate the tactics required and send the corresponding speed, altitude and heading commands to the cockpit displays and AFSC. Two types of MCC messages were transmitted by SAGE: MCC-Region Origin (MCC TACAN) and MCC-Interceptor (MCC-NO TACAN). In MCC Region Origin, target X and Y coordinates were referenced with respect to the SAGE origin. In MCC-Interceptor, target position was referenced with respect to the interceptor. The default mode was MCC-Region Origin. MCC-Interceptor usually had to be requested by the pilot except when MCC messages where sent as backup messages during the CC dominant mode.

In the Cockpit. TDDL interaction between SAGE and the F-106 was controlled in the cockpit using the Data Link Converter Receiver Control Panel located on the right console. The pilot could select a SAGE frequency using one of 26 preset channels, or manually insert a four digit channel. Using the Address Select switch, the pilot could select one of 32 aircraft addresses that would be compared to the aircraft address embedded in the SAGE signal as one of the means for validating the transmission. The receiver also accommodated back-up data link voice communication.

The Display/Automatic Mode Selector Switch on the main instrument panel determined what data link information was displayed and how intercept tactics would be executed. There were two positions for the switch: MAX RANGE and DL MIN TIME. Each had different meanings depending on which data link mode was dominant (CC or MCC). For example if by SAGE command the dominant mode was CC, then there was no difference between the MAX RANGE and DL MIN TIME settings because SAGE was performing and issuing the interceptor guidance calculations. However, if the dominant mode was MCC, the position of the switch governed the profile and tactics commanded by the MA-1 computer to approach and attack the target. Typical tactics included: cutoff, pursuit, stern before offset, stern after offset and non-commit. The pilot could determine the selected tactic by setting his Homing Point Selector Switch to “U” and monitoring the target altitude marker on the AVVI. The marker would position at an altitude corresponding to one of the above tactics for a period of time, and then revert back to its normal function.
Additional TDDL displays in the cockpit included the positioning of target and interceptor “bugs” on the Tactical Situation Display (TSD), command airspeed and mach on the Airspeed Mach Indicator (AMI), command altitude and target altitude on the Altitude Vertical Velocity Indicator (AVVI), command bank and steering on the Attitude Direction Indicator (ADI), command heading and target course and bearing on the Horizontal Situation Indicator (HSI) and time to offset and target range and azimuth relative to interceptor on the radar scope. The proper functioning of the data link was indicated by the Computer Mode Annunciator on the main instrument panel, which could display either “DL” for current data link, “DR” for dead reckoning or a barber pole if target information is over one minute old or no MCC data link was received during attack. Once the pilot locked the radar onto the target, all data link information was suspended while the MA-1 computer conducted the attack and firing sequence. Upon completion of the attack and selection of AUTO NAV by the pilot, data link information would resume for return to base vectoring.

Dude:

Thanks for all this. I'm a former Air Force Russian-language comint operator who flew missions against the Soviet Union in '64-'66 (RC-130s out of Rhein-Main AB). During that time the Sovs were using a system roughly equivalent to SAGE, and guiding MiG-21s with it. I've been studying the Soviet system and, as you might expect, in many features it parallels SAGE. But your data is the most detailed I've found yet for how SAGE actually worked for American pilots. Please keep it up!

If anyone's interested I'll post data about the Soviet system as I get it together. I've a manual for the 1963 version and it's very detailed on ground usage and has an overview for how the groung-air datalink worked.