to the equipment and facilities.  The OCS has been augmented with a transportable GA capability

and Back Up MCS capability.

1.6.4.3  User Segment (1986 to Present)

1.6.4.3.1  GPS JPO Activities

In April 1985, the contractor was selected for the Phase III production GPS UE.  Low rate initial

production of the UE was begun and the first set was delivered to the JPO in June 1988.  In

January 1992, full rate production of the UE was approved.  The Phase III production UE

includes the 5 channel Receiver 3A (R 2332/AR) for airborne use, the 5 channel Receiver 3S (R 

2331/AR) for shipboard use, the 2 channel Receiver OH (R 2399/AR) and UH (R 2400/AR) for

helicopter use, and the RPU 1 (R 2401/U) for manpack and ground vehicle use.

In 1989, a contract was awarded for 2 channel SPS C/A code receivers to be used primarily for

demonstration and training.  These receivers are known as the Small Lightweight GPS Receiver

(SLGR, AN/PSN 10).  They are suitable for vehicle mounting or handheld use.  In 1990, a large

second purchase was made.  Although originally intended for nontactical use, these receivers were

used extensively in support of Operation Desert Shield and Operation Desert Storm.

In November 1990, a contract was awarded to develop a 5 channel 3/8 ATR (Air Transport

Rack) size Miniature Airborne GPS Receiver (MAGR) for use in aircraft where space is severely

limited.  The contract to deliver operational models was awarded in April 1993 with the first

delivery occurring in July 1994.  Two versions of the MAGR have been produced.  One version

uses an RF interface directly from the antenna (R 2512/U) the other (R 2514/U) uses an IF

(intermediate frequency) interface from an antenna electronics unit.

In February 1993, a contract was awarded to produce a hand held PPS GPS receiver.  Designated

the Precision Lightweight GPS Receiver (PLGR, AN/PSN 11), it weighs less than 4 pounds, is

self contained as a handheld unit, and can be adapted for vehicle mounting.  Delivery of the PLGR

began in September 1993.

In the 1990s, the GPS JPO has continued to sponsor activities to improve the functions and

performance of military GPS receivers.  Activities are continuing that will improve anti jamming

performance of GPS antennas, antenna electronics units, and receiver signal processing.  In

1994, procurement efforts were begun for a new Controlled Reception Pattern Antenna (CRPA).

The new CRPA will be compatible  with the form, fit, and function of the existing CRPA

system procured by the JPO.  Efforts are also underway that will allow Receiver Autonomous

Integrity Monitoring (RAIM) to be implemented where enhanced GPS integrity or compatibility

with civil aviation is desired.  Other efforts are underway to add differential GPS (DGPS) to

future military PPS receivers, to support new applications, such as precise positioning and aircraft

precision approach.  Additional programs that are underway or under consideration include a

space based GPS PPS receiver, a miniaturized PLGR, and a Survey GPS Receiver (SGR).  Since

1993, the GPS JPO has been developing standards for a next generation PPS receiver module that

can be embedded in other military systems.  The JPO will not procure embedded GPS receivers

(EGRs), but will provide technical support so that other military programs can procure the EGR

as part of another system.

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