New GPS handheld receiver planned for '04: fast processors, advanced displays will simplify satellite-guided navigation in the field.

• Author: Sheehy, Christian B.

The U.S. Defense Department is preparing to test a next-generation Global Positioning System handheld receiver that will be lighter and easier to operate than current devices, officials said.

The new system, known as the Defense Advanced GPS Receiver (DAGR), will replace the so-called Precision Lightweight GPS Receiver (PLGR).

The two companies competing in the DAGR program are Raytheon Space and Airborne Systems, in El Segundo, Calif., and Rockwell Collins, of Cedar Rapids, Iowa. These firms received contracts valued at $357.1 million and $361.1 million, respectively.

Each contractor will supply the GPS Joint Program office with 250 test units by May 2003. The JPO will oversee the selection process in the fall of 2003. Operational testing and low-rate production could begin sometime in late 2004. The next phase of the program could be worth between $300 million and $400 million.

"Simply put, DAGR will reduce the logistical burden on the war fighter, enabling greater tactical situational awareness in less time, using less equipment," said Air Force Maj. Keith Hirschman, project officer for the DAGR program. "Not only will DAGR provide the soldier with ready-to-use data in one-sixth the time of PLGR, but it will do it with less than half the battery consumption, in a package less than half the weight and only two-thirds the footprint."

PLGR technology has for a decade now enabled soldiers to use coordinated position, velocity and timing data in continuously mobile, unfriendly environments. The performance of the PLGR depends on a single frequency (L1) for reception and switchover from commercial to encrypted GPS signal.

DAGR technology proposes to eliminate this reliance on one frequency by adding a second frequency (L2), enabling soldiers to obtain position information with greater accuracy, in less time, said officials.

"In essence, DAGR has twice PLGR's capability of receiving clear satellite signal transmissions," said Mike Fleenor, business director for land navigation at the Raytheon Company. "Attempts at jamming or spoofing signals, where successful against PLGR, are less likely to be effective using dual-frequency DAGR, since the bandwidth of each frequency will be available for signal acquisition."

To prevent unauthorized users from logging on a U.S. receiver, the GPS Joint Program Office implemented a security technique built around a dual-key architecture for controlling access to military encrypted P(Y) code. Color-coded, red or black, cryptographic keys represent the basic authorization levels for operating in classified P(Y) code.

The addition of a now-mandatory GPS security device called the Selective Availability Anti-Spoofing Module (SAASM) into DAGR will offer the user the guarantee that, in the event of enemy capture, the receiver encrypted architecture will be fully resistant to any attempts at reverse-engineering its components.

At the crux of military GPS security is the reliance on Precise Positioning Service-Security Module (PPS-SM) data storage and processing. Supporting a network of digitally-based receivers, PPS-SM and an Auxiliary Output Chip (AOC) produce the GPS encrypted P(Y) code, a...