Military GPS User Equipment

During the 1980s, development of initial-generation military receivers proceeded, leading to production of multiple types of military receivers in the early 1990s [39]. Airborne and shipborne receivers processed five channels in parallel, while receivers for ground vehicles and manpack were one- and two-channel receivers that employed sequential processing, where one or two channels were tracked at a time.

A two-channel receiver, known as the Small Lightweight GPS Receiver (SLGR), processed only the C/A-signal and was used extensively in Operation Desert Storm [39]. Example early military receivers are shown in Figure 3.6.

Figure 3.6. Early military receivers: Manpack Global Positioning System (GPS) receiver circa 1980 (left), RCVR-3A Airborne GPS receiver circa 1988 [40] (right). Images © Rockwell Collins, used with permission. Source: Reproduced with permission of Institute of Navigation

DARPA-sponsored developments led to the Miniature GPS Receiver (MGR) and later, the Precision Lightweight GPS Receiver (PLGR), a handheld receiver that was touted for weighing less than 4 kg. Each took advantage of rapidly advancing microelectronics technology to provide greater capability and lower power consumption in a smaller package. Adaptive anti-jam antenna systems were also introduced in the 1990s, using multi-element antenna arrays known as controlled reception pattern antennas (CRPAs) and antenna electronics that formed spatial nulls in the direction of jammers.

More recent military receivers provided similar functionality with reduced size, weight, and power. The Defense Advanced GPR Receiver (DAGR), introduced in 2004, weighs less than half of the PLGR, while the Miniature Airborne GPS Receiver (MAGR) weighs one-third of the RCVR-3A [41]. They are portrayed in Figure 3.7. Distinctively, the helical antenna of the PLGR is replaced by embedded patch antennas in the DAGR.

Figure 3.7. Followon military receivers: PLGR and DAGR (left), and MAGR (right). Images © Rockwell Collins, used with permission. Source: (Left) Reproduced with permission of Defense Industry Daily. (Right) Reproduced with permission of GlobalSecurity.org

Development of next-generation military receivers, known as Military GPS User Equipment (MGUE), has proceeded since the mid-2000s. These receivers are known as YMC/A receivers for their ability to receive P(Y)-, M-, and C/A-signals. After delays and cost overruns, MGUE full production is currently planned for sometime after 2020.