Ground Based – Global Positioning Ssystem Receiver Application Module


The Ground Based - GPS Receiver Application Module (GB-GRAM) is intended to provide a low-cost, standardized "embeddable" GPS product solution utilizing the Joint Chiefs of Staff mandated Selective Availability Anti-Spoofing Module (SAASM) security architecture. The SAASM technology provides enhanced protection for United States and Allied forces operating in hostile environments. The dual-frequency, SAASM-based, L1/L2 GPS receiver is targeted for insertion into a variety of new and legacy Department of Defense and Foreign Military Sales platforms requiring a 24-hour, 7 days a week position, velocity, navigation and timing solution available in all-weather conditions.


Since the GPS Directorate, in partnership with the United States Army Communications and Electronics Command, led the initial contract with Rockwell Collins in May 03, over 91,000 GB-GRAMs have been ordered by more than 45 Department of Defense and FMS product managers and platform integrators. The functions and capabilities of the GB-GRAM have been tailored by the GPS Directorate to suit the needs of user platforms requiring relatively low-dynamics including mounted and dismounted land and waterborne vehicles to include Command and Control, targeting, communications, Intel, PC's and a myriad of other platforms seeking to integrate a small, low-cost, dependable all-weather, GPS capability.


The GB-GRAM embeddable GPS "receiver on a card" is packaged in the Small Serial Interface form factor and has been designed to meet a "standard" set of functional and performance requirements specified in the MIL-PRF-GB-GRAM-300 Performance Specification and the electrical interface specified in the Interface Control Document ICD-GPS-153.


The SAASM technology provides enhanced protection for United States and Allied forces operating in hostile environments. The smaller Type II SSI is designed to replace the current Type I SSI is now available. The Type II is designed to be completely form-fit-function backward compatible with previous Type I SSI cards.

General Characteristics

Power: A modest 3.3VDC at 1.3W steady state tracking
Weight: Less than 100 grams (Type I)
40 grams (Type II)
Dimensions: 2.45" x 3.4" x 0.60" (Type I)
2.45" x 1.76" x 0.285" (Type II)
Price: Contract pricing dependant on quantity
Interfaces: 3 serial ports - BDDP, COM1, COM2
Timing: HAVEQUICK time code
Accuracy: Horiz - < 6.7 meters
Vert - < 12.3 meters
Velocity - < 0.4 meters/second
Time - < 200 nanoseconds
TTFF: < 90 seconds

PRIME CONTRACTOR: Rockwell Collins