• • • • • • • • •
Automatic glideslope intercept Navigation fix maneuvering H aiding pattern Wind Freeze mode Sensor definition Training display assignment Scenario generation and control Increased target capacity (to 32).
When Sperry Univac was awarded the ARTS 111 contract for the installation of automated ATC systems at 62 major airports in the US systems testing required a more sophisticated target generator. Since target detection was done by the software instead of digitizer hardware. the target generator was changed to generate target replies rather than target reports. Target replie s were generated on a sweep-bysweep (radar interrogation) basis; a hit or miss could be specified for each sweep (up to 45 sweeps). With thi s approach the target generator could be used to test the target detection software as well as the tracking functions. Another enhancement was that the rates of cha nge to parameters could be specified (e.g .. turn rate. rate of climb/ descent. and rate of veloci ty change). Al so. the mode C alt itude validity and mode 3 1A beacon code validity could be specified. This version of the target generator could simulate up to six targets. For ARTS 111 the target generator program had to be recoded for a different processor. The next FAA project was for a M inimum Safe Al titude Warning System (MSAW) for all ARTS Ill-equipped airports. MSAW provides warning signals to air traffic con troll ers when con trolled aircraft are threatened with becoming
'controlled flight into terrain '. Testing MSAW required extensive simulation because of the need for a carefully controlled environment and the impracticality of using targets of opportunity or test aircraft to create low altitude situations. The use of scenarios was important because the situation could be replayed identically each time with no need for operator keyboard entries. Adjustments of system parameters and input data could be made until optimum test conditions were obtained. The automatic glideslope intercept function was also used extensively to test approach path monitoring warnings. For demonstration of metering and spacing for the ARTS Ill system. the target generator program was further expanded to provide several functions. including the following : • • • • •
Fix navigation Metering and spacing controller ILS capture Fast time Command feedback Error simulation.
The first three functions will be described later; however. command feedback and error simulation are unique to metering and spacing. Command feedback provides a means of associating target generator commands with metering and spacing commands so th at the simulated aircra ft can be controlled withou t operator 1ntervent1on. Error simulation creates a more realistic testing environment by allowing for the failure of targets to report a certa in percentage of the time on a scan-to-scan basis. called blip-scan error and to allow targets to simulate performance
errors. which live aircraft may make when performing maneuvers. The Conflict Alert project provides for controllers to be alerted of predictions of aircraft potentially coming too close to other controlled aircraft . For the Conflict Alert system acceptance testing. the scenario generation and control capability was used extensively because of the difficulty in using live aircraft to create conflict situations. No additional functions had to be added to the target generator program for this test . In 1976 Sperry Univac began work on an ATC systems project to implement the following: •
CDR - Addition of a continuous data-recording capability at all ARTS-Ill-equipped airports • EARTS - An enroute system at Anchorage. Honolulu. Neliis AFB. and San Juan • ARTS II IA - Installation of enhanced version's of the ARTS Ill system at 2 9 airports • New York TRACON - Replacement for. and expansion of. the Common I FR Room for controlling traffic at JFK. La Guardia. Newark. lsl1p and Westchester airports. The target generator and scenario generator software were used 1n essentially th eir current evolved state of enhancement. combining the functions developed for many of the previous proiects. The scenario generator was modified to include all operational keyboard commands rather than JUSt target generator-re lated commands as origi nally designed. The New York TRACON ATC system required the most extensive target s1m ulat1on . In add1t1on to its use during a very complex and lengthy acceptance test. the target generator 1s an integral part of t he operational software. It 1s used for cont roller trai ning purposes and for subsequent software baseline testing as the operational functions are expanded . The capacity test for the New York TRACON system presented a unique problem . Because the system receives input from four rada rs. and the required capacit y for each sensor was 300 tracks. the large volume of data could not be generated 1n rea l-time or stored in the available memory. A special version of the target generator was developed to generate the data off-line and to store 11 on a disc pack. then to read the data from the disc during the ca pacity test For a military ATC system the target generator was once again extensively