Multiple Aircraft Tracking System for Coordinated Research Missions

Abstract

The Multiple Aircraft Position System (MAPS) was developed by the Convective Storms Division of the National Center for Atmospheric Research, in response to the need for aircraft position in the coordination of large field projects involving several research aircraft. Radio interferometer techniques are used to provide rapid, accurate determination of positions for up to 10 aircraft furnished with special airborne radio beacons. Three remote interferometer array sites receive the signals from the airborne beacons, each transmitting at a unique frequency. Each remote site is tuned to one beacon frequency at a time according to a programable polling sequence; several phase difference measurements are made from the received signal. These data then are telemetered to a central control station where they are transferred to a computer that calculates the direction cosines from each remote site to the airborne beacon, and thus determines the position of the beacon. The aircraft positions then are immediately available for display. The deployment of MAPS near Miles City, Mont, for the 1981 Cooperative Convective Precipitation Experiment (CCOPE) field program is described. Science Laboratory of the New Mexico State University, using techniques that had been used to track rockets at White Sands Missile Range. The interferometer receivers and some of the data handling equipment were purchased from the Physical Science Laboratory. From experience gained during several field tests in Colorado, major changes in the system design were made by CSD, and the system was first deployed as a developmental system for testing in the Miles City area in 1980. Further refinements were made after those tests, prior to the first use of MAPS in field operations during the Cooperative Convective Precipitation Experiment (CCOPE) field program in 1981 (cf, Knight, 1982). The following sections will briefly describe how MAPS works, as well as some of the major problems to be overcome with this type of system. It should be noted that MAPS was not designed to be a general-purpose aircraft tracking system, but was tailored to the requirements of CSD's field programs. Some of the features specific to the CCOPE 1981 field program will be discussed.

Early electrification and precipitation development in a small, isolated Montana cumulonimbus

“…The Multiple Aircraft Position System (MAPS) [Johnson and Fink, 1982], developed by the Convective Storms Division of NCAR was used to determine the position of the aircraft. In this study the MAPS positions were augmented by radar returns of the aircarft from the CP-2 radar and from position information recorded on the aircraft.…”

Convection Initiation and Downburst Experiment (CINDE)

“…Unique transponder codes for CINDE aircraft were extracted from the FAA tracking-radar data stream, fed into MOCCA, and overlaid on the radar display. While not as accurate as the aircraft tracking system described by Johnson and Fink (1982) for research applications in CCOPE, this tracking system was nevertheless quite suitable for research coordination and for issuing advisories regarding hazardous weather avoidance.…”

The Cooperative Convective Precipitation Experiment (CCOPE), 18 May-7 August 1981

“…Many participants commented on the value of this communal lunch arrangement for the morale and smooth running of the whole operation.6 The aircraft tracking system (MAPS, or Multiple Aircraft Position System) was developed for CCOPE and is the subject of a brief article byJohnson and Fink (1982). Likewise, the operations room set-up is described in another brief article byBiter and Johnson (1982).Downloaded from http://journals.ametsoc.org/doi/pdf/10.1175/1520-0477(1982)063<0386:TCCPEM>2.0.CO;2 by guest on 05 September 2020…”